There are several concerns regarding the risk of excessive bleeding following minor oral surgery in anticoagulated patients and those on antiplatelet medication. Most of these are unfounded for dentoalveolar procedures. In most dentoalveolar procedures, we have the advantage of a bony cavity where physical pressure can be effectively applied to obtain hemostasis. This can be further augmented with other local hemostatic measures (sutures, surgical R, AbgelR, etc.). This obviates the need to stop antiplatelet drugs (read following content). However, in patients on dual antiplatelet therapy, the authors suggest caution when operating in critical areas like the foor of the mouth as hematomas can cause airway embarrassment.

Conventional antiplatelets bind irreversibly to platelets and the normal clotting process is restored only with the production of new, unaffected platelets (Fig. 3.5, Table 3.3). It takes 5–10 days for platelets to be produced in the quantity required to produce a clinically normal platelet action. In the interim, if a procedure causes excessive bleeding, the only reliable way to ensure hemostasis is platelet transfusion. However, the newer ones are reversible and can be stopped for 24 h prior to the procedure as a "switch on-switch off"

**Fig. 3.5** Mechanism of action of commonly used antiplatelet drugs

**Table 3.3** Commonly used antiplatelet agents and their characteristics [15]

drug. But these are very expensive and most of the belowpoverty-line patients are likely to be on older antiplatelets for some time to come.

Deep Vein Thrombosis and Pulmonary Embolism. Myocardial infarction. Acute Ischemic Stroke

#### **<IP_ADDRESS> Maxillofacial Surgery**

Patients who need procedures with low risk of bleeding (e.g., fxation of fracture of the parasymphysis) may continue oral antiplatelet/anticoagulation therapy. This applies especially to high-risk patients (e.g., mechanical heart valves). However, when the risk of bleeding is obvious, it outweighs the beneft of continuing antiplatelet/anticoagulant therapy. In such cases, heparin is used as bridge therapy.

#### **<IP_ADDRESS> Bridging with Heparin**

In cases where the patient is at high risk for a thromboembolic episode, a "bridge"—a balance between surgical bleed and risk of thrombosis may be achieved either with intravenous unfractionated heparin or with subcutaneous lowmolecular-weight heparin [16].

#### **<IP_ADDRESS> Anticoagulants and Oral/Maxillofacial Surgery**

While several indications exist for the use of anticoagulants, the authors have noted that there is signifcant resistance in the medical community to prescribe anticoagulants in these cases and they are often replaced by antiplatelets in India. This is especially true for the rural patient who may not have regular access to monitor his anticoagulation status. However, in urban centers, NOAC are in regular use.

Common indications for anticoagulation—prevention of thrombotic events in:

Mechanical Heart Valves. Atrial Fibrillation.

The target International Normalized Ratio (INR) range for most conditions is between 2.5 and 3.5.

#### **<IP_ADDRESS> Minor Oral Surgery**

It is beyond doubt that warfarin/acetrom therapy need not be discontinued and INR need not be normalized prior to dentoalveolar surgery. The risk of a thrombotic episode does not justify the risk of a minor bleed that can be controlled by local measures [17]. Simple dentoalveolar surgery (e.g., three simple extractions) can be safely performed with an INR of 3.5 or less with appropriate local hemostatic measures [18]. However, it is imperative that the patient is closely followed. It is sensible to schedule these procedures in the morning.

#### **<IP_ADDRESS> Major Maxillofacial Surgery**

Depending on the indication for anticoagulant therapy and the drug used, the decision regarding the control of anticoagulation is made. Ideally the prescribing physician is involved in decision making (Fig. 3.6) (read following content).

#### **3.5.5 Infective Endocarditis Prophylaxis**

Much has changed over the years with regard to infective endocarditis (IE) and antibiotic prophylaxis. Since the guidelines change by the year, the authors strongly recommend that the surgeon takes recourse to his smartphone to keep abreast of the changing scenery (Tables 3.4 and 3.5).

**\***OAC; Oral anticoagulant,POD; Post-operative day, INR; International normalized ratio, LBR; Low bleeding risk, SBR; Standard bleeding risk, HBR; High bleeding risk, CrCl; Creatinine clearance ©Association of Oral and Maxillofacial Surgeons of India

**Fig. 3.6** Perioperative management of oral anticoagulants [19]

#### **3.5.6 Implantable Cardioverter Defbrillators (ICD)**

An ICD is a battery-powered device implanted in a patient that generates a small electrical impulse. Indications are patients at risk of sudden cardiac death—ventricular fbrillation/ventricular tachycardia, malignant ventricular tachyarrhythmias. ICDs are also used to treat Brugada syndrome [21].

#### **<IP_ADDRESS> Implications**

Bleeding: patients may either be on antiplatelets or anticoagulated. (read earlier content).

Devices: Electrocautery, especially monopolar diathermy, may interfere with the device and this may have to be turned to a "safe mode" by the electrophysiology technician. The concerned cardiologist should be able to assist with the technical details.

Infective endocarditis prophylaxis: Risk being low, current guidelines DO NOT recommend prophylaxis for these patients.

#### **3.6 Impact of Central Nervous System Disorders in Maxillofacial Surgery**

Of the many conditions which affect this system, the effects of epilepsy and stroke are most commonly encountered in maxillofacial surgical practice.

**Table 3.4** AHA, ESC, and NICE guidelines for infective endocarditis prophylaxis

**Table 3.5** Revised AHA guidelines for infective endocarditis prophylaxis [20]

Note: *i.m* intramuscular; *i.v* intravenous

a Or other frst- or second-generation cephalosporins at equivalent adult and pediatric dose

b Cephalosporins should not be given to a patient with a history of anaphylaxis, angioedema, or urticaria with penicillin or ampicillin

#### **3.6.1 Epilepsy**

A seizure is a result of excessive electrical discharges in a group of brain cells, whereas epilepsy is described as a disease characterized by recurrent seizures. A single seizure does not constitute epilepsy, which is defned as having at least two or more unprovoked seizures. The incidence worldwide is approximately 0.5–0.9%, affecting over 50 million individuals [22].

Etiology of epilepsy can be divided as primary or idiopathic, where the cause is unknown and this constitutes the vast majority of cases. In secondary or acquired epilepsy, the cause can be determined and these include metabolic, genetic, structural, and functional abnormalities.

An increase in the incidence in the elderly can be attributed to conditions such as stroke, tumors, trauma, and Alzheimer's disease. Systemic conditions include diabetes, hypertension, infections, electrolyte imbalances and dehydration, or lack of oxygen. Withdrawal from high-dose, long-term use of drugs such as cocaine, heroin, barbiturates, amphetamines, and alcohol can also precipitate seizures [23]. Seizures generally last for a few seconds to minutes. Although many types exist, they are broadly divided into two groups (Fig. 3.7).

Primary generalized seizures—which begin with involvement both sides of the cerebral hemispheres.

Partial seizures—start in a localized area [25].

#### **<IP_ADDRESS> Basic considerations**

While recording history, the duration, type, frequency of the seizure as well as the most recent episode must be recorded as well as the type of medication taken, if any. If the patient is aware of how the seizure starts, if there is any warning or "aura," this too must be noted [23].

Several factors are capable of provoking seizures. These include improper use of medication, lack of sleep, drug abuse, drug interactions, hypoglycemia, electrolyte imbalance among others. Antiepileptic drugs should generally be continued without alteration.

#### **<IP_ADDRESS> Outpatient maxillofacial considerations**

If seizures are predictable, then appointments should be scheduled accordingly. Frequency of seizures determines the urgency of treatment. Procedures, unless emergent, should be postponed if frequency of seizures is high. The clinician must reduce anxiety to the patient. Short morning appointments are ideal. Sudden bright lights, noise, or movements must be avoided as these may trigger a seizure [23].

#### **<IP_ADDRESS> Major Surgical Considerations**

Trauma is a common consequence of seizures and may result in lacerations of the face or oral cavity and fractures of the maxillofacial skeleton. Other injuries include hematomas, dislocation of temporomandibular joint (TMJ) fracture/loss of teeth. An electroencephalogram (EEG) along with imaging such as CT/MRI is recommended if there is no previous seizure history. Open reduction should be preferred over closed for treatment of facial fractures, as further episodes of seizures might lead to aspiration if intermaxillary fxation (IMF) is attempted [25].

Local anesthetic is considered safe in well-controlled epileptics, as is sedation. General anesthesia is preferred in uncontrolled epileptics, especially if coupled with a mental defcit, as a seizure might be triggered due to stress from diffculties in communication. One drawback of general anesthetic is temporary anoxia to the brain, which itself might trigger a seizure [26].

#### **<IP_ADDRESS> Precautions, complications, & management**

As mentioned earlier, appropriate recording of history gives an insight into planning the procedure, particularly for elective surgeries. Objects with the potential to cause harm must be kept away from the vicinity of the patient. Antiepileptics such as phenytoin have been known to cause gingival enlargement, which can be managed either by surgery or by a change in medication. Aspirin, antifungal azoles, metronidazole can interfere with phenytoin. Propoxyphene and erythromycin can interfere with carbemezepine. Contraindicated drugs are chlorpromazine, fumazenil, ketamine, lignocaine in large doses and quinolones, tramadol, and tricyclic antidepressants [25].

#### **<IP_ADDRESS> Management of an acute episode on the dental chair**

If possible, all foreign body/material should be removed from the oral cavity. The chair should be reclined to a supine position with the patient turned onto their side to minimize the

©Association of Oral and Maxillofacial Surgeons of India

risk of aspiration. Passive restraint is used only to prevent them from falling out of the chair. A recurrent seizure or a seizure of more than 3 min requires drug administration. The patient should be monitored to prevent airway obstruction. After the patient recovers, appropriate medical consults should be arranged. Elective treatment should be postponed [23]. However, prolonged seizures, which continue in spite of medication, may lead to status epilepticus, which may be fatal if untreated. Airway patency and peripheral venous access are frst line of management. If seizures persist even after administration of drugs such as lorazepam or diazepam, the patient must be shifted to the hospital for further management.

#### **3.6.2 Stroke**

Stroke (cerebrovascular accident) is a serious, occasionally fatal neurologic event characterized by the rapid appearance of a focal defcit of brain function. It is estimated that 85% of patients presenting with stroke would have sustained a cerebral infarction because of inadequate blood fow to a part of the brain, with the remainder suffering from an intracerebral hemorrhage. Often, survivors of cerebrovascular accidents are left debilitated in motor function and/or speech [27].

A stroke may be a result of hemorrhage or ischemia as given later (Fig. 3.8).

The initial presentation of stroke includes loss of combination of sensory and motor functions with occasional loss of consciousness. The presenting features include hemiparesis or paraparesis, dysphagia, ataxia, aphasia, dysarthria, loss of vision. Early detection is by assessing facial and arm weakness and any slurring of speech. Mechanism of stroke may be ischemic, primary intracerebral hemorrhage, and subarachnoid hemorrhage. The oral impact of stroke includes facial weakness, dysphagia, and speech impairment [29].

#### **<IP_ADDRESS> Basic Considerations**

At the outset, it is paramount to assess the extent of disability of the patient—both physical and mental, as this is vital in determining whether performing the procedure is safe in the outpatient setting. There may be a dependence on others for basic needs. History of past strokes needs to be elicited: including dates, severity and current neurological defcit. Treatment is performed in consultation with the neurologist and precautions according to the specifc characteristics of the stroke.

#### **<IP_ADDRESS> Maxillofacial considerations**

Outpatient appointments must be ideally scheduled in the morning and must be of short duration. Patients must be treated in an upright position as much as possible, as they are more prone to aspiration due to impaired protective refexes. Another important consideration is diffculty in oral hygiene maintenance due to facial weakness and xerostomia, which may be observed as a side effect of medications prescribed [24]. Although procedures must be deferred for as long as possible, in unavoidable circumstances such as trauma or progressing head and neck cancers, general anesthesia is reasonably safe. Shorter duration surgery, intraoperative monitoring and maintaining cerebral perfusion, anticoagulation status, and precaution all aid in reducing the incidence of a further episode.

Antiplatelets and anticoagulation: Ref previous section.

#### **<IP_ADDRESS> Precautions**

Monitoring of Blood pressure pre- and postprocedure is vital, procedures should be deferred if systolic is >180 mmHg or diastolic is >110 mmHg. Poststroke patients are usually on antiplatelet or anticoagulant medications; hence, coagulation status must be ascertained prior to any procedure. Vasoconstrictors are to be used cautiously as they can increase the risk of adverse outcomes like cerebral hemorrhage due to acute hypertension [29].

Opiods are best avoided as they may result in severe hypotension and benzodiazepines may cause respiratory depression. The practitioner must be mindful that sudden loss of consciousness could result from stroke, and emergency management is the protection of airway and shift to hospital [24].

**Fig. 3.8** Common causes of stroke [28]

### **3.7 Impact of Psychiatric Disorders in Maxillofacial Surgery**

Psychiatric and psychological disorders are of rising concern in modern society, affecting all aspects of a patient's life, including oral health. Poor oral hygiene is usually due to a combination of lethargy, side effect of medications, and possibly fear of treatment [30]. Common disorders encountered in practice are related to mood, anxiety, substance dependence, eating, or somatoform in nature [31].

Occasionally, oral symptoms may be the initial or single manifestations of the underlying issue. Patients who present with atypical facial pain with vague symptoms, oral dysesthesia, abnormal sensation or movement, salivation often with no identifable physical cause could be suffering from undiagnosed underlying emotional disturbances. Early detection in such cases benefts both the patient and the practitioner [32, 33].

#### **3.7.1 Maxillofacial Considerations**

Pain related to the TMJ and associated structures seems to be another condition, which fts into the previous category, commonly seen and treated by the maxillofacial surgeon. In the absence of an identifable organic cause, there must be a low threshold for considering an underlying emotional disturbance.

Patients with diagnosed psychiatric conditions and on medication present with obvious oral symptoms. Most common among these are dental caries and periodontal disease. The primary cause of these is due to decreased salivary fow or xerostomia, which is a side effect of medications, including tricyclic antidepressants, lithium carbonate, phenothiazines, and benzodiazepines. Sialorrhea or excessive salivation is a well-known side effect of clozapine and reduction in dose may be of use [32]. Candidiasis is another condition, which may manifest due to xerostomia, especially in denture wearers. Fear of dental treatment is well known. However, recognition of the nature and extent of this fear is important to prevent noncompliance. Anxiety disorders and phobia often stem from two types of experiences, a painful or traumatic procedure, usually at a young age, or a negative interaction with healthcare professional [32]. A specifc maxillofacial consideration in this respect is suturing of facial wounds under local anesthetic, in young children. The authors recommend sedation if not a general anesthetic, particularly in extremely young children, where such procedures are required.

Alcohol, tobacco, and drug abusers are particularly tricky to treat, be it minor or major maxillofacial surgery. The amount of local anesthetic required to produce adequate analgesia tends to be higher in such patients. These groups of patients are at a higher risk of developing oral cancer. Effects of withdrawal can be signifcant and this must be kept in mind preoperatively, intraoperatively, and postoperatively especially where procedures of long duration and extended stay are planned. Use of drugs like chlordiazepoxide might be required to offset delirium tremens, particularly in the postoperative period. Head and neck cancer particularly affects the psyche, making a psychologist a very important member of the multidisciplinary team.

Patients suffering from clefts of the orofacial region require multiple surgeries at various stages of their life and the effects of surgery and rehabilitation can be debilitating on both the child and the parents. Timing of surgeries is vital as they disrupt the life of the entire family of the child and for this parental counselling is extremely important [33].

While management of trauma might be comparatively straightforward, one must not underestimate the effect on the psyche in the recovery phase, especially if this is coupled with post-traumatic stress disorder (PTSD). Although these injuries are among the most common treated, these can lead to depression, drug abuse, antisocial behavior, especially in those with a post-traumatic residual defect [34].

Orthognathic surgery, while primarily carried out for cosmetic reasons, occasionally may be performed for functional reasons, as in obstructive sleep apnea. Counselling prior to surgery is useful and the entire process can take up to 3 years. Serious psychological and psychosocial problems have been reported [33].

While awareness of maxillofacial surgery and its benefts is gradually growing in our country, with most centers providing information about technical aspects of surgery, the psychological aspect is often ignored. Communication needs to improve and an assessment of patients' emotional state before and after surgery could help in improving patient satisfaction [33].

#### **3.8 Dental and Maxillofacial Implications in Liver Disease**

#### **3.8.1 Introduction**

At approximate of 1.4 kg, this reddish, rubbery structure forms an important organ system. Along with the Gall Bladder and Pancreas, the liver works to digest, process, and absorb food. Liver aids in detoxifcation in the body and is the primary organ of drug metabolism. It also helps in the production and transport of bile [35].

#### **<IP_ADDRESS> The Function of the Liver** [36]

Detoxifcation—Removal of ammonia, exogenous hormones

Liver dysfunction hence alters all of these functions, thereby disrupting the homeostasis in the body, which has to be taken into consideration when providing dental and maxillofacial therapy.

Vitamin K levels are signifcantly lowered in advanced liver disease hampering the production of coagulation factors. This, along with portal hypertension, results in thrombocytopenia, thus resulting in excessive bleeding, which is of consideration during dental and maxillofacial management [37].

#### **3.8.2 Classifcation of Liver Dysfunctions** [35]

Acute or Chronic

#### **<IP_ADDRESS> Viral Hepatitis**

Hepatitis A—caused due to Hepatitis A virus, spreads via the orofecal route. It is endemic in nature and is self-limiting.

Hepatitis B—caused by (HBV) that replicates within the hepatocyte; it is a dangerous form of viral disease with high risk to healthcare workers. The surface antigen is routinely detected in the saliva of infected individuals, and hence transmission through the saliva is of concern to the Oral Surgeon [38]. Prevalence of HBV infection is three to fve times more in dentists than the general population. Younger individuals with chronic HBV infections have a greater prevalence of developing hepatocellular carcinoma.

Hepatitis C—Caused by a bloodborne virus, it is the most common cause for chronic hepatitis, which over long term could lead to cirrhosis or hepatocellular carcinoma.

#### **<IP_ADDRESS> Autoimmune Hepatitis**

It is a chronic liver infammatory disease as a result of IgG Hypergammaglobinemia as a result of environmental or viral factors inciting an autoimmune response leading to cirrhosis [39].

#### **<IP_ADDRESS> Fulminant Hepatitis**

A sudden acute and severe dysfunction of the liver with resulting hepatocellular necrosis and encephalopathy with a very poor prognosis. These patients require liver transplant.

#### **<IP_ADDRESS> Cirrhosis**

It is the irreversible damage to the hepatic architecture due to long-term fbrous scarring. A rise in the production of total liver collagen and matrix protein that is troublesome to the function and form of the liver [40].

#### **<IP_ADDRESS> Hepatocellular Carcinoma**

It is the ffth most common cancer and a life-threatening malignancy with poor survival rates. HBV and HCV are the most common causes of it.

#### **<IP_ADDRESS> Alcoholic Liver Disease**

It is the 10th most common cause of death with 3% of fatalities in the industrialized world [35]. Alcoholism results in varied disruption of the hepatic system ranging from simple fatty liver to complicated life-threatening cirrhosis.

#### **3.8.3 Oral Manifestations of Liver Disease**

Foetor hepaticus (Breath of the dead odor of rotten eggs with garlic) is a characteristic late feature of liver dysfunction [36]. Evidence of liver diseases has been noted in the oral cavity as icteric mucosal alteration with gingival bleeding and also associated hemorrhagic changes like hematoma, petechiae [37]. HCV-associated hepatitis is noted as a common cause for Sjogren's syndrome and lichen planus in the oral cavity [41]. Alcoholic hepatitis in association with nutritional defciencies could cause glossitis along with delayed healing post surgery [37]. Occasionally, parotid enlargement is also noted. These oral manifestations are associated with concomitant general symptoms of liver disease such as hepatomegaly, malaise, confusion, fatigue, weight loss, nausea, and altering the well being of the person [37].

#### **3.8.4 Implications of Liver Disease**

#### **<IP_ADDRESS> Liver Disease and Maxillofacial Surgery**

Risk of viral contagion and crossinfection is one of the implications of viral hepatic disease. Hep C viruses are found to be stable at room temperatures for approximately 5 days. The virus is also detected at different surfaces in the clinic after the patient is treated. It is vital to maintain adequate sterilization and observe strict universal protection when treating such patients. Needlestick injury precautions must be adhered to.

Detailed history taking is important to identify any indications of liver disease, including that of hepatitis, jaundice, alcohol intake, recreational drugs, or rank abuse. Abnormal bleeding patterns are elicited in history [42]. Past surgical history provides a valuable indicator for any doubts regarding the adequate functioning of the liver system. Additional information of identifying the etiology for cirrhosis and any continued risk factors like alcohol consumption should be noted [35]. Review of blood investigations such as serum bilirubin, albumin, alanine aminotransferase (ALT), Aspartate aminotransferase (AST), complete blood counts, and coagulation profle must be performed prior to any surgical planning [43].

Elective surgery is contraindicated in acute phases of viral hepatitis and acute liver failure.

Plasma level of coagulation factors is depressed in liver disease and can potentially alter the hemostasis. Complete blood counts, PT, PTT, INR, and liver functions tests are mandatory in all patients with any signs/symptoms of liver dysfunctions. The goal of surgical therapy is to minimize trauma to the tissues. It is also advisable to involve the hematologist if required. Any dental or minor oral surgical procedure must terminate with the use of local hemostatic agents or antifbrinolytic agents to aid in hemostasis. Maxillofacial surgical work and major invasive oral surgery are ideally performed in the hospital. Fresh Frozen Plasma and Vitamin K infusions to optimize the coagulating process might be required to offset intraoperative bleeding.

Patients with liver disease are more susceptible to infection with a greater risk post invasive dental or maxillofacial procedure. Antibiotic prophylaxis is recommended.

Drug metabolism is altered in these patients (Table 3.6). Unlike serum creatinine, which is an indicator of renal function, the liver function test is more of an indicator for liver damage. Hence, it is diffcult to obtain exact dose modifcation formulae when medicating patients with liver disease. Drug usage, dosage, and interactions must be consulted with the specialist prior to their usage.

The metabolism of these drugs is well tolerated in mild liver dysfunctions but is impaired in severe dysfunction and hence requires modifcations and contraindications. The beta lactams mainly utilized in maxillofacial surgery are quite safe. NSAIDS are to be used with caution to avoid gastric bleedings [35]. Hepatotoxic drugs should be avoided eg. erythromycin, ketoconazole, halothane, phenytoin etc. Prilocaine or articaine is preferred over lidocaine. Sedatives,

hypnotics or opiods should be used with caution. A balance has to be struck constantly to maintain the anesthesia and concern is of the depressive action of alcohol and central nervous system depressors. Postoperative care in view of alcohol withdrawal must be noted. Ensure alcohol-based mouth rinses are avoided.

#### **3.9 Maxillofacial Implications in GI Disorders**

#### **3.9.1 Perioperative Maxillofacial Implications**

#### **<IP_ADDRESS> GERD**

Extraesophageal symptoms of GERD must be identifed to prevent any airway issues primarily. Due to delayed gastric emptying, preoperative fasting hours must be prolonged. In high-risk patients, Proton pump inhibitors and H2 receptor antagonists are potent drugs to increase gastric pH and reduce secretions. Nasogastric suctioning through nasogastric tube aids in protecting the airway from gastric secretions during surgery. It is important to manage nausea and vomiting postoperatively effectively.

#### **<IP_ADDRESS> Peptic Ulcers**

Stress reduction protocol is vital. GI symptoms from NSAIDS are delayed and identifed when the ulcers are in an advanced stage with a greater risk of bleeding. Corticosteroids must be avoided in these patients along with NSAIDS. GI bleeding due to ulceration could cause anemia and has to be managed prior to any surgery. Surgery is contraindicated in active peptic ulcers. Ranitidine, when used over a long phase for management, could cause thrombocytopenia [44].

#### **<IP_ADDRESS> Ulcerative Colitis**

One must rule out anemia in these patients and assess the effect of long-term steroid therapy. Antibiotics such as clindamycin, ampicillin, and cephalosporins are implicated in aggravation of colitis and are hence avoided. If the patient has undergone Vitamin K malabsorption, its effects are considered.

Postoperative nausea and vomiting, though not a complication, is still detrimental in patient management perioperatively. Volatile inhalation anesthetic agents and opiod analgesics are emetogenic and need to be used with caution. Postoperative anxiety, dehydration, and pain could result in nausea and vomiting. Scarred ulcers in the duodenum delay gastric emptying resulting in vomitus. Antiemetics in these patients must be prescribed at the end of the surgery and dexamethasone 1 h prior to the surgery is helpful if not contraindicated. In high-risk patients, antiemetics must be administered prior to anesthesia itself [45]. Postoperative ileus could occur due to prolonged opiate use during anesthesia, decreased potassium levels, trauma or due to iliac bone harvesting as a complication or resultant severe pain.

#### **3.10 Pregnancy**

Pregnancy is often associated with changes in cardiovascular, endocrine, hematological, respiratory, gastrointestinal, and genitourinary system. These alterations may occasionally be subtle and can lead to disastrous complications if not identifed [46].

#### **3.10.1 Physiologic Changes**

There will be increase in the heart rate leading to an increase in cardiac output. Cardiac output increases mostly in the frst trimester and remains fairly unchanged with minimal increase in the fnal trimester.

During the second and fnal trimesters, a decrease in blood pressure and cardiac output may occur while the patient is in a supine position. This is caused by the gravid uterus compressing the inferior vena cava leading to a decreased venous return to the heart leading to hypotension, bradycardia, and syncope. This phenomenon is called *supine hypotension syndrome* [47].

The concentration of all coagulation factors, other than factors XI and XIII, is increased. As Thrombin-mediated fbrin generation increases during pregnancy, this combines with an increase in the aforementioned clotting factors and hematocrit, leading to the hypercoagulable state of pregnancy. This leads to a higher risk of deep vein thrombosis (DVT) and pulmonary embolism (PE).

In the abdomen, the enlarging uterus displaces the stomach onto the spleen and liver leading to high intragastric pressure. This and the delayed gastric emptying leads to regurgitation and gastric refux. Hyperventilation that begins in the frst trimester might increase throughout pregnancy. This has obvious implications on drug dosage, route and timing of administration.

In the frst trimester, glomerular fltration rate increases 30–50%, which results in an increase in clearance of creatinine, uric acid, and urea. This leads to a decrease in levels of the same. While prescribing drugs, doses may need to be increased to account for this rapid clearance [48].

#### **<IP_ADDRESS> Minor Surgery**

While minor oral surgery is not a contraindication in the pregnant patient, it is advised that the oral surgeon should consult with the patient's obstetrician to address specifc concerns should dental emergencies arise during the frst trimester.

Unless emergency treatment is required, it is advisable to defer treatment during the frst trimester because of the potential vulnerability of the fetus. The second trimester is the safest time to perform the routine dental treatment. No elective treatment is advisable late in the third trimester.

#### **<IP_ADDRESS> Dental Radiology**

Two important factors to be considered are the dose of radiation to be given and the time of gestation. Animal and human data clearly support the conclusion that no increase in congenital anomalies due to exposures totaling less than 0.05– 0.1 Gy during pregnancy. The amount of radiation used in dental radiographs is well below the threshold dose [47]. With modern features such as high-speed flm, fltration, collimation, and use of lead aprons, dental radiography is deemed quite safe.

#### **<IP_ADDRESS> Major Surgery**

Elective surgery should be postponed until after delivery. If possible, nonurgent surgery should be performed in the second trimester when preterm contractions and spontaneous abortion are least likely. Fetal safety requires that potentially dangerous drugs are avoided and adequate uteroplacental perfusion is ensured. No anesthetic drugs have been proven to be clearly hazardous to the human fetus. However, teratogenic effects of nitrous oxide have been demonstrated in animal models following prolonged administration in high concentration [49].

Anxiety in itself leads to decrease in uteroplacental perfusion secondary to increase in circulating catecholamines. Appropriate timing of surgery and anxiolysis is of paramount importance.

#### **3.10.3 Drug Usage in Pregnancy**

Most drugs cross the placental barrier by simple diffusion. Hence, the major concern of drug administration during pregnancy is the potential of teratogenic adverse effects. The period of maximum risk for teratogenicity is during organogenesis. This occurs from the end of the predifferentiation period until the end of the 10th week after the last menstrual period (Table 3.7).

**Table 3.7** Commonly used safe and unsafe drugs during pregnancy [46]

#### **3.11 Endocrine Disorders**

#### **3.11.1 Diabetes**

Diabetes is an endocrine disease manifesting as hyperglycemia, leading to microvascular and cardiovascular complications. Type 1 diabetes mellitus is an autoimmune pancreatic beta cell destruction leading to inadequate production of insulin. In type 2 diabetes mellitus, there is a condition of insulin resistance in addition to defects in insulin secretion by the pancreatic beta cells, and increased endogenous glucose production, primarily by the liver [50].

The current recommendation for diagnosis of diabetes stands at >126 mg/dl of fasting plasma glucose levels or a 2-h plasma glucose level of 200 mg/dl [51]. The Endocrine Society guidelines indicate that patients with hyperglycemia and glycated haemoglobin (HbA1c) of 6.5% or higher can be identifed as having diabetes [52].

Optimal glycemic control is advised in each patient to avoid hyperglycemia or hypoglycemia. The surgical patient with diabetes is at higher risk of perioperative morbidity and mortality and subsequently longer length of hospital stays. This is mainly due to increased chances of surgical site infections and systemic infections, other complications like acute kidney injury, acute coronary syndromes, acute cerebrovascular accidents, hospital-acquired diabetic ketoacidosis, etc [53].

The stress of surgery and anesthesia derails the glycemic control of the patient due to the metabolic response to surgery. Nondiabetic patients evoke a catabolic response with a release of cortisol, glucagon, catecholamines, etc., promoting hepatic glycogenolysis and gluconeogenesis causing hyperglycemia. There is a catecholamine-induced inhibition of insulin production as well as insulin resistance. The type of anesthesia and the length of the procedure are also said to infuence the amount of catabolism [54].

The preoperative preparation for a diabetic patient begins with a thorough history, including the type and dosing of medications, any history of cardiac events, or diabetic ketoacidosis. ECG is mandated as these patients have a higher occurrence of hypercholesterolemia, hypertension, macrovascular disease, autonomic neuropathy, and hence silent ischemia. If the ECG does suggest so, further investigation is indicated [55].

Renal function tests should include serum urea and creatinine. Hypertension should be ruled out or treated if present. Diabetic neuropathy should be evaluated as it may cause aspiration, silent myocardial ischemia, or even sudden death. It may manifest as postural hypotension, heartburn, or resting tachycardia [56].

HbA1c is usually advised in diabetic patients undergoing treatment as it refects mean control over the previous 3 months. This allows one to estimate the quality of glycemic control before the consultation and adaptation of treatment to fxed objectives. It is also important to know the duration of the diabetes, dependence on insulin, and whether the glycemic control is achieved by oral hypoglycemics and lifestyle modifcation.

#### **<IP_ADDRESS> Management of Patients Undergoing Procedures**

The recommendations for target glycemic control vary. The Endocrine Society and the American Diabetes Association/ AACE Practice Guidelines recommend that patients on insulin maintain a target preprandial glucose of less than 140 mg/ dl and a random Blood Glucose (BG) of less than 180 mg/dl for patients treated [52]. The Joint British Diabetes Societies guideline, however, recommends that insulin therapy be commenced when random blood glucose levels exceed 180 mg/dl [53].

#### **<IP_ADDRESS> Preoperative Glycemic Control in patients on Oral Hypoglycemic Agents**

#### **<IP_ADDRESS>.1 Minor surgery**

Patient should adhere to his daily oral diabetic medication and follow his usual diet [50].

#### **<IP_ADDRESS>.2 Major surgery**

• (Dipeptyl Peptidase-4) DPP-4 inhibitors are not contraindicated throughout the perioperative period [54].

#### **<IP_ADDRESS> Preoperative Glycemic Control in Type 2 Diabetics on Insulin**

Patients on basal insulin: If they are on twice daily dosing then morning dose to be reduced to 80% of normal dose; whereas if those on single dose then evening dose to be reduced to 80% [57].

If the morning glucose levels are above 120 mg/dl, Neutral protamine Hagedorn (NPH) insulin and premixed formulations are reduced by 20% the evening before surgery and by 50% the morning of surgery. If not, morning insulin dose is withheld [58].

Naturally, these are guidelines and the diabetologist will tailor the doses to the individual requirement of the patient.

#### **<IP_ADDRESS> Preoperative Glycemic Control in Type 1 Diabetics on Insulin**

#### **<IP_ADDRESS>.1 Minor surgery:**

#### **<IP_ADDRESS>.2 Major surgery:**

These patients are at risk of developing stress-induced hyperglycemia and ketoacidosis and hence need insulin coverage during perioperative period. These patients should receive 80% of basal insulin dose the evening before surgery and on the morning of surgery in order to prevent hypoglycemia [54].

#### **<IP_ADDRESS>.3 Intraoperative glycemic control:**

The endocrine society recommends an intraoperative BG level within 180 mg/dl [52].

Levels above that are treated either with subcutaneous rapidacting insulin analogs or with an IV infusion of regular insulin. In patients undergoing short surgeries (under 4-h operative time), ambulatory surgeries, expected hemodynamic stability and those expected to resume oral diet soon can be managed with subcutaneous rapid-acting insulin correction scales [3]. When it is used, the BG should be checked every 2 h [52].

An IV insulin infusion is preferred where there is anticipated hemodynamic disturbance, signifcant fuid shifts, expected changes in temperature, inotropic support, or lengthy operative times (greater than 4 h). In this situation, hourly insulin monitoring is needed.

#### **<IP_ADDRESS>.4 Postoperative glycemic control:**

For noncritical and non-ICU patients, the subcutaneous sliding scale insulin is used with BG being checked every 2 h. If BG drops below 70 mg/dl, insulin is stopped and oral dextrose or iv dextrose is given. For patients in the ICU, continuous iv insulin infusion is given instead of the subcutaneous sliding scale for BG > 180 mg/dl. Oral antidiabetic agents are best avoided in hospitalized patients due to the limited data available on their safety and effcacy. DPP-4 has shown promising results for in-patient hyperglycemia control [54].

#### **3.11.2 Hypo/Hyperthyroidism**

The thyroid gland releases the hormone thyroxine (T4) and its active form T3. The thyroid hormones are released upon stimulation by the thyroid-stimulating hormone (TSH) released from the pituitary gland. This is, in turn, stimulated by thyrotropin release hormone (TRH). Secretion of T3 and T4 is regulated by the negative feedback loop modulating release of TSH [59].

Thyroid hormones play a critical role in maintaining metabolic homeostasis in the adult. Thyroid-related disorders are due to either overproduction of thyroid hormones (thyrotoxicosis) or hormone defciency (hypothyroidism). These situations may arise due to infectious, autoimmune, proliferative, or tumorous pathologies [60].

Most patients with well-compensated thyroid disease do not need special consideration prior to surgery. Patients with a newly diagnosed thyroid disorder around the time of surgery will need to undergo risk assessment and optimization before surgery.

Routine thyroid screening is not done for asymptomatic patients unless there is a reason to suspect thyroid dysfunction. Thyroid disease present with a myriad of symptoms clinically. These include-unexplained weight changes, and fne tremor or changes in bowel habits, skin, hair, exophthalmos, goiter, abnormal refexes. Palpitations, tachycardia, or bradycardia are common cardiovascular manifestations. In such situations as well as in patients with a known thyroid disorder, a TSH test should be included in the preoperative analysis [61].

#### **<IP_ADDRESS> Hypothyroidism**

Hypothyroidism may be primary (due to thyroid disease) or secondary due to hypothalamo-pituitary disorders. Commonly, it is due to thyroid loss from surgery, irradiation, autoimmune diseases, or drug induced [59]. The diagnosis is confrmed by blood tests revealing low T3 and T4 levels and high TSH in primary and decreased TSH in secondary hypothyroidism. These patients pose challenges during perioperative period due to their effects on various organ systems.

#### **<IP_ADDRESS>.1 Physiologic Challenges**

Cardiac disturbances like increased peripheral vascular resistance, decreased cardiac output; Respiratory implications like increased incidence of pneumonia, impaired respiratory drive, respiratory muscle weakness. Decreased renal perfusion, decreased gastric motility, and slower drug metabolism need to be considered.

One of the most serious complications of surgery in hypothyroid patients is myxedema coma. It is associated with a mortality rate as high as 80%. It is characterized by altered mental status, which may manifest as coma or seizure, and hypothermia, bradycardia, hyponatremia, heart failure, and hypopnea. It is precipitated by surgery, infection, cold exposure, and administration of sedatives [61].

#### **<IP_ADDRESS>.2 Management**

A condition of euthyroidism is usually targeted preoperatively and elective surgery is usually postponed. Once TSH values normalize, surgery can be performed. Use of sedatives, benzodiazepenes and Opiods should be avoided [59].

For urgent and emergent procedures, surgery may be performed in mild-to-moderate hypothyroidism with levothyroxine cover preoperatively. Surgery should be postponed in patients with severe hypothyroidism in case of nonemergent surgery. In an emergency, thyroid hormone levels should be normalized as rapidly as possible, using IV levothyroxine in a loading dose of 200–500 μg followed by 50–100 μg IV daily [62].

#### **<IP_ADDRESS> Hyperthyroidism**

It is commonly due to autoimmune disease (e.g., Graves' disease), multinodular goiter, or adenoma presenting as thyroid nodule. The diagnosis is confrmed by elevated serum T3 and T4. It usually causes exopthalmos, heat intolerance, anxiety, sweating, diarrhea, and weight loss [59]. It has a positive ionotropic and chronotropic effect on the heart coupled with decreased vascular resistance [61]. Hence, these patients manifest tachycardia, arrhythmias, or cardiac failure frequently.

Thyroid storm is a severe manifestation of uncontrolled hyperthyroidism and is characterized by tachycardia, confusion, fever, gastrointestinal complaints, and potentially leading to cardiovascular collapse. It is precipitated by pain, anxiety, trauma, or GA. Hence, elective surgery should always be postponed in patients with overt untreated hyperthyroidism. Hyperthyroidism is usually treated by β-blockers like atenolol or metoprolol as they decrease the sympathetic overactivity. When there is no time to render a patient euthyroid as in emergency cases, cardiac monitoring and adequate β-blockers with antithyroid medication should be given [61]. While epinephrine with lidocaine is not contraindicated, caution should be exercised. Benzodiapines should be avoided. Carbamizole causes agranulocytosis and this can manifest as oral ulcers.

#### **3.11.3 Adrenal Gland Disorders**

#### **<IP_ADDRESS> Primary Adrenocortical Hypofunction**

Addison's disease occurs due to autoantibody-mediated destruction of the adrenal cortex leading to failed cortisol and aldosterone secretion. It may also occur due to tuberculosis, histoplasmosis, sarcoidosis, etc [59]. Due to lack of adequate corticosteroid production, these patients are prone to hypotensive collapse, hypoglycemia, profound weakness, and dehydration (Adrenal crisis).

Adrenal crisis is rare in outpatient oral surgery. However, patients with Addison's disease who need surgery should be covered with supplemental steroids. Drugs like barbiturates, azole antifungals, etomidates, phenytoin, and rifampins should be avoided as they accelerate cortisol metabolism.

#### **<IP_ADDRESS> Secondary Adrenocortical Insufciency**

Corticosteroids are prescribed as long-term treatment for various ailments such as infammatory bowel disease, blood dyscrasias like idiopathic thrombocytopenia, rheumatologic disease, reactive airway disease, and immunosuppression for transplant recipients, etc. due to their immunosuppressive, anti-infammatory, metabolic, and hemodynamic properties. This external source of long-term steroid can lead to secondary adrenal insuffciency that may manifest in the perioperative period [63].

In a healthy individual, corticotrophin-releasing hormone (CRH) has a diurnal pattern of release from the hypothalamus. This in turn acts on the anterior pituitary to release the Adrenocorticotrophic hormone (ACTH). ACTH acts on the adrenal cortex to release cortisol (hydrocortisone), corticosterone, and mineralocorticoids. Circulating corticosteroids have a subsequent negative feedback effect on CRH and ACTH release. This constitutes the hypothalamic-pituitary adrenocortical (HPA) axis [59].

Normally, an unstressed adrenal gland secretes approximately 8–10 mg of cortisol per day (Table 3.8). Stress, such as illness or surgery, is the stimulus for raised production of cortisol. During surgical stress, the rate varies between individuals and also upon the type of surgery. It is usually up to 50 mg/day for minor procedures and up to 75–150 mg/day for more complex procedures, rarely exceeding 200 mg/day. However, patients on exogenous corticosteroids aren't able to secrete adequate amounts of corticosteroids in response to stress due to HPA axis suppression and a resulting low level of ACTH and CRH leading to atrophy of the zona fasciculate of adrenal cortex [63].This may predispose them to develop adrenal crisis, with rapidly developing hypotension, hypoglycemia, collapse, and even death [59].

Even though there is no consensus on the exact dosage of corticosteroids that leads to hypofunction of the adrenal cortex, doses greater than physiologic doses of cortisol lead to suppression [59]. HPAA suppression does not extend beyond 1 year after exogenous steroid therapy is stopped [64]. Hence, those at risk are:

These patients require steroid cover/supplementation when undertaken for surgeries. Most dentoalveolar and maxillofacial surgeries result in stress and hence require steroid supplements, but most other dental procedures do not require any additional steroid supplements [59].

Following table shows the normal corticosteroid response to the particular level of stress and the appropriate steroid cover needed in cases of adrenal suppression (Table 3.9):

During the procedure, blood pressure and blood sugar levels should be monitored. NSAIDs should be avoided to avoid increasing risk of peptic ulceration. Prophylactic antibiotics should be given in such patients to avoid postoperative infections.

#### **3.11.4 Renal Disorders**

The kidneys are responsible for eliminating metabolic waste; fuid and electrolyte homeostasis; and to maintain acid and base balance. The kidneys also affect the cardiovascular and hematologic systems.

**Table 3.8** Approximate potencies of systemic corticosteroids relative to cortisol [59]

**Table 3.9** Normal corticosteroid response to the particular level of stress and the appropriate steroid cover needed in cases of adrenal suppression [63]

The best parameter to assess the function of the kidneys is the glomerular fltration rate (GFR). It is measured by calculating the creatinine clearance based on serum creatinine (SC). The normal value of GFR for an adult male is 130 ml/1.73 m2 and is 120 ml/1.73 m2 for an adult female. Chronic kidney disease occurs when the GFR is reduced by at least 50 ml/min [65].

Patients with chronic kidney disease who are either on dialysis, dialysis naive, or renal transplant recipients or posttransplant patients require modifcation of treatment plan from a surgical point of view. These patients always have a risk of developing acute renal failure in the postoperative period either due to pre-existing renal dysfunction or solely due to the effects of surgery.

#### **<IP_ADDRESS> Acute Renal Failure (ARF)**

ARF is the rapid loss of renal function over the course of days to weeks, resulting in the patient's inability to clear nitrogenous waste, including creatinine and urea, from the body [66]. The term Acute Kidney Injury (AKI) has replaced acute renal failure in current literature. Perioperative AKI is a leading cause of morbidity and mortality due to increased risk of sepsis, anemia, coagulopathy, and mechanical ventilation.

There are three types of ARF based on etiology: prerenal, renal, and postrenal causes. The most common cause of AKI in perioperative period is the prerenal cause and the ischemic acute tubular necrosis (renal AKI) due to hypoxic damage to medullary region secondary to hypovolemia, hypotension, and dehydration [67]. Prerenal AKI and ischemic ATN are a part of a spectrum of manifestations of renal hypoperfusion. Hypotension or hypovolemia may be due to preoperative factors like hemorrhage, diarrhea, fasting, use of diuretics, due to intraoperative factors like ongoing blood loss, activation of sympathetic refexes, and due to postoperative factors like intravascular volume depletion, myocardial infarction, etc [68]. Hypotension and hypovolemia result in activation of the sympathetic nervous system and the renin–angiotensin–aldosterone axis, which compromises GFR by inducing afferent arteriolar renal vasoconstriction. Other common causes of AKI are the use of NSAIDs, ACE inhibitors, nephrotoxic drugs like aminoglycosides, radiocontrast materials, myoglobin, hemoglobin, and amphotericin B. Pre-existing diseases like diabetes, hypertension, and obstructions of the urinary system also lead to perioperative AKI [68].

The strategy around perioperative AKI is ideally prevention. Preoperatively potential risk factors such as volume depletion, hypotension, sepsis, nephrotoxin exposure, and pre-existing chronic kidney disease should be identifed and elective surgery should be postponed till optimization is complete. Anemia should be corrected before surgery. The choice of fuid in intraoperative resuscitation is usually a balanced crystalloid solution like Ringer's lactate and not a chloride-rich crystalloid. Hydroxyethyl starch is best avoided. Mean arterial pressure should be maintained and hemodynamic stability is of utmost importance. Diuretics should be only given in cases of volume overload and not for increasing GFR. Norepinephrine is preferred over dopamine as it maintains renal perfusion pressure, but the role is still not very clear [67].

#### **<IP_ADDRESS> Chronic Renal Failure (CRF)**

CRF is permanent renal insuffciency that develops over months or years caused by the structural and intrinsic damage of the glomerulus or tubulointerstitial system. This usually occurs when GFR is reduced by 50 ml/min. If necessary treatment is not started, most cases of CRF would lead to End Stage Renal Disease (ESRD). ESRD is maintained by regular dialysis or by transplant, in the absence of which, death may occur [68].

Preoperative assessment:

Detailed history and physical examination;

Cardiac work up as dictated by clinical symptoms. ECG and

Echocardiogram

Complete blood count

Metabolic panel, serum magnesium, and phosphorus levels Coagulation profle.

Coronary artery disease and congestive heart failure are commonly found in patients with ESRD and those on dialysis. Hence, cardiac workup and monitoring is required in the perioperative period. Maintaining euvolemia perioperatively in ESRD patients is mandatory. For patients not undergoing dialysis, euvolemia can be achieved with appropriate hydration or diuresis. Dialysis is usually performed a day before surgery to prevent fuid overload and to reduce uremic complications (bleeding). Postoperative dialysis helps to achieve euvolemia if large amounts of fuids were given during surgery. Heparin is withheld if dialysis is performed on the day of surgery.

Anemia complicates CKD due to the decreased production of erythropoietin. Transfusion should be considered in the perioperative period when hemoglobin levels fall below 8–10 g/dl due to surgical blood loss in patients with ESRD. If anemia has been detected, erythropoietin should be initiated several weeks before the elective surgery with iron supplementation to raise hemoglobin to the desired level. Patients who have ESRD may be susceptible to more intraoperative and postoperative bleeding due to platelet dysfunction caused by uremia. Hence, NSAIDs and dipyridamole should not be given within 72 h before surgery to patients who have ESRD due to their effects on platelet function. Hypertension and glycemic control should be tightly monitored in such patients as well.

These patients have ineffcient mechanisms of drug clearance that inherently predispose them to adverse drug responses. Hence, NSAIDs, aminoglycosides, benzodiazipines, morphine, and radiocontrast media are avoided. Drugs like propofol, fentanyl, and inhalational anesthetics are usually the preferred drugs of choice.

#### **3.12 Patients with Non-head and Neck Malignancies**

#### **3.12.1 Introduction**

The most common cancers in India in women are Breast, Oral, Cervical, ovary, and esophagus. Men tend to be afficted with head and neck cancers, lung, esophagus, stomach, and colorectal cancer [69]. The cancers that most commonly metastatize to the jaws and oral soft tissues are breast, lung, prostrate, thyroid, kidney, stomach, and colon [70]. Another group of malignancies that receive chemoradiotherapy are the lymphoproliferative and hematologic malignancies [70].

*Chemotherapy* is often employed either with an intent of palliation or for cure. It may be administered as adjuvant therapy or as neoadjuvant therapy. Cytotoxic chemotherapeutic agents have hematologic effects (myelosuppression) as well as nonhematologic effects. The effects of myelosuppression, i.e., leukopenia, thrombocytopenia, and anemia start after 5–7 days with the nadir occurring at 10–14 days. It is usually followed by bone marrow recovery [71]. Hence, the oral surgical treatment should be planned in a manner that it doesn't coincide with the nadir of the myelosuppression where the neutropenia can be as low as 500.

*Radiotherapy* is a part of treatment for a variety of Head and neck cancers either as primary treatment modality or as adjuvant therapy to the primary tumor or to the associated lymphatic structures. Unlike the effects of chemotherapy, effects of radiotherapy are more long lasting. These include mucositis, xerostomia, trismus, radiation-induced fbrosis, and dysguesia.

#### **3.12.2 Treatment Protocol**

#### **<IP_ADDRESS> Chemotherapy**

It is best to undertake a dental screening before the start of the chemotherapy so that the hopeless teeth can be extracted, be restored, periodontal therapy, alveoloplasty be performed, and primary closure be done. After extraction, it takes approximately 10 days to 6 weeks for healing to be enough for chemotherapy to start [72]. Ill-ftting and loose dentures should be discontinued and replaced ideally with implants especially in patients scheduled to take systemic bisphosphonates or RANK-L therapy as it might lead to osteonecrosis of the jaws [73]. Fluoride treatment can also be done.

However, patients suffering from leukemia, lymphomas have a state of myelosuppression even before the start of the

**Table 3.10** Modifcation of invasive dental treatment according to hematologic indices [75]

chemotherapy. Only acute situations need to be dealt with. Elective treatments can wait till the time the patient is in optimal clinical and hematological parameters, which is usually until after chemotherapy is over. Hence, extractions of grossly carious and severely periodontally compromised teeth, ill-ftting denture, etc. should be addressed. For extractions to be done, or other invasive dental procedures, hematologic indices should be evaluated and antibiotic prophylaxis should be considered [74] (Table 3.10).

Once the chemotherapy starts, a gap of 1 week before the next cycle is essential before any dental intervention. For surgical procedures that cannot wait, like facial trauma or infection, the complete blood counts should be assessed and consultation should be sought with the medical oncologist to determine the nadir in blood counts, the timing of the chemotherapy cycle, and duration [72]. For platelet levels below 40,000/mm3 , platelet transfusions are usually needed [76].

Opportunistic infections may complicate mucositis and may be of viral, fungal, or bacterial origins. Treatment should be guided by culture and sensitivity. Febrile neutropenia needs to be treated usually by intravenous antibiotics like amoxicillin and clavulanic acid with a fuoroquinolone or clindamycin with fuoroquinolone. Hematopoeitic growth factors like granulocyte colony-stimulating factors or granulocyte-macrophage colony-stimulating factors are effective drugs for prophylaxis and treatment of febrile neutropenia. Mucositis occurs in almost all patients and causes great diffculty in feeding, hydrating, and causes pain. It is preferable to manage it with saline mouth rinses rather than with chlorhexidine mouthwashes. Some chemotherapeutic agents are also neurotoxic and cause a deep mandibular pain as well as altered taste sensation and dysguesia. Most of these symptoms subside after cessation of treatment [72].

#### **<IP_ADDRESS> Radiotherapy**

The same prophylactic measures of extraction, restoration, alveoloplasty, etc. have to be taken before radiotherapy as for chemotherapy. Additionally, jaw-opening exercises should be initiated and coronoidectomy should be considered as a part of the ablative procedure [72].

#### **3.12.3 Prevention and Treatment of Osteonecrosis After Chemotherapy and Radiation**

Osteonecrosis of the jaws occurring in an irradiated bone is called osteoradionecrosis (ORN). Those occurring in a patient on antiresorptive therapy like bisphosphonates or monoclonal antibodies to RANK-L is termed Antiresorptive osteonecrosis of jaws (AONJ) [72]. The incidence of ORN in areas of jaws that have received greater than 60 Gy of radiation is 5–15%. Incidence of AONJ in patients who have received denosumab is 1.3% and is 1.8% in patients treated with nitrogen-containing bisphosphonates [77, 78].

**Acknowledgments** Dr Prithvi Bachalli, Consultant Oral and Maxillofacial Surgeon Rangadore Memorial Hospital, Bangalore

Dr. Prashanth Bhat, Consultant Oral and Maxillofacial Surgeon

Rangadore Memorial Hospital, Bangalore Dr Shobha Hegde, Registrar Oral and Maxillofacial Surgeon

Rangadore Memorial Hospital, Bangalore

#### **References**

of the Nation's states-The India state-level disease burden initiative. New Delhi: ICMR, PHFI and IHME; 2017. https://www.healthdata.org/sites/default/fles/fles/policy\_report/2017/India\_Health\_ of\_the\_Nation%27s\_States\_Report\_2017.pdf

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons. org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

## **Medical Emergencies in Oral and Maxillofacial Surgical Practice**

Nallamilli V. S. Sekhar Reddy

### **4.1 Introduction**

Oral and Maxillofacial Surgery has evolved over the last few decades. Although it is now practiced as a full-fedged hospital-based specialty, a signifcant amount of work is still carried out under local anesthesia; predisposing toward a medical emergency precipitated particularly by stress. Oral and Maxillofacial surgeons thus deal with the medical emergencies in an offce or hospital setting on a regular basis.

Emergency team response in most countries is prompt. The published guidelines from these countries refect this in the advice for the general practitioner; doing the essential minimum toward the sustenance of life in case of a medical emergency and to prioritize escalation of call for help to the emergency team. However, in some parts of the world, the response time of the emergency team is expected to be comparatively longer, due to various policy issues. The chapter considers these special circumstances, to suggest some additional measures toward the management of the emergency, while waiting for the arrival of the emergency team.

Also, the general advice in the management of a medical emergency during an outpatient procedure in a clinic is aimed at general practitioners, who may not necessarily be exposed to training in clinical skills like the placement of an intravenous cannula. Oral and Maxillofacial surgeons are expected to be well versed with this life-saving simple clinical skill and the protocols discussed here take this into consideration.

The management of emergency should follow the universally accepted ABCDE approach [1], which helps the clinician to follow a systematic approach in an emergency situation where the most life-threatening condition is assessed and is given the top priority. Lack of airway kills the patient frst, then the lack of ability to breathe followed by the absence of circulation. ABCDE approach incorporates:

Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, Telangana, India

Medical Emergencies that are life threatening and need immediate remedial measures on an emergency basis are discussed here:

### **4.2 Acute Asthmatic Attack**

Stress, Anxiety, and Infection can precipitate an asthmatic attack in individuals who are prone. Unfortunately, all three of them can be part of OMFS practice.

#### **Box 4.1**

Note: Asthma that is part of a generalized anaphylactic reaction needs Adrenaline via intramuscular route.

#### **Signs and Symptoms:**

**4**

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 49

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_4

N. V. S. Sekhar Reddy (\*)

#### **Management:**

### **4.2.1 Life-Threatening Acute Asthma**

Asthmatic attack can sometimes be severe and may fail to respond to standard bronchodilator therapy. This can be fatal if no proper treatment is given. When an asthmatic attack failed to respond to the treatment and getting worse, the patient will need urgent transfer to appropriate medical center.

#### **Signs and symptoms of severe life-threatening asthma:**

#### **Treatment:**

### **4.3 Acute Adrenal Insufciency/Adrenal Crisis/Steroid Crisis/Addisonian Crisis**

Sudden and severe hypotension in patients who cannot mount a normal stress-induced cortisol response. The stress can be physiological or psychological. Adrenal crisis can be seen in patients who were taking glucocorticoids regularly or who have taken glucocorticoids for a considerable period of time in the past, patients with Addison's disease, hypopituitarism, or in other conditions associated with decreased adrenocorticotropic hormone (ACTH) production.

#### **Box 4.2**

*Oxygen—Supports Combustion*

*Do not oil, grease, or lubricate cylinder controls.*

#### **Signs and Symptoms:**

#### **Treatment:**

	- Children from age 2 to 11 years, 2–4 mg/kg body weight.
	- Above 11 years: give adult dose.
	- Adult dose: 100 mg by IV.
	- If unable to secure IV access, give the same dose by IM route.

### **4.4 Airway Obstruction**

As the mouth is the primary area of our specialty, clinicians may have to deal with acute airway obstruction. As with everything else, prevention is the most important thing.

#### **Signs and Symptoms:**

#### **Treatment** [7]:

	- Start with chest compressions even if there is pulse, as chest compressions can help relieving the obstruction.
	- Patient may need oxygen supplementation.

#### **Box 4.3**

Aspiration of small objects like burs, endodontic fles, and reamers may not cause immediate lifethreatening airway obstruction, but retrieval of these rather small and prickly instruments from lungs is a very diffcult task needing bronchoscopy and can result in serious lung infections and damage. Prevention takes priority.

#### **4.5 Anaphylaxis**

Sudden onset, severe form of life-threatening allergic reaction, which can be seen following exposure to an allergen. Remember topical anesthetic gels, chlorhexidine mouth wash, and even contact with latex gloves can trigger anaphylaxis in individuals who are sensitive [8].

Prompt recognition and immediate response are key to success.

#### **Signs and Symptoms:**

#### **Treatment:**

	- Oxygen supplementation at 15 L/min.
	- Keep assessing the airway and provide necessary support.
	- Chlorpheniramine maleate IM or IV.
	- Hydrocortisone sodium succinate IM or IV.
	- Establish Intravenous access.
	- Ringer's lactate solution or 0.9% Normal saline to support circulation.
	- Reassess the need for further adrenaline.

#### **Box 4.4**

Adrenaline is to be administered if there is severe respiratory distress or when there are signs of shock.

#### **Box 4.5**

Adrenaline—Life-saving drug for Anaphylaxis

	- Site: I.M Anterolateral thigh Dosage:

#### **Box 4.6**

#### **Second-line drugs:**

Hydrocortisone sodium succinate: 100 mg Route: IM or Slow IV 12 years and adults: 200 mg IM/IV 6–12 years: 100 mg IM/IV 6 months to 6 years: 50 mg IM/IV Chlorpheniramine Maleate Supply: Chlorpheniramine Maleate 10 mg/1 mL Ampoule Route: IM or IV 12 years and adults: 10 mg IM/IV 6–12 years: 5 mg IM/IV 6 months to 6 years: 2.5 mg IM/IV

#### **4.6 Chest Pain**

Experiencing chest pain in an outpatient offce can be a frightening experience for both the patient and to the attending clinician. Thorough understanding of the pathophysiology of these acute cardiac events is very important for the clinician to stay composed and initiate appropriate measures to prevent mortality. Myocardial infarction may not always have the typical features of chest pain and especially diabetic patients may not have pain. Hence, a high index of suspicion is what is required.

Causes of chest pain:

Hyperventilation is associated with anxiety and often a young person who is quite frightened of the intended treatment, the breathing gets very heavy resulting in decreased carbon dioxide levels in the blood.

#### **4.6.1 Angina**

Transient decrease of oxygen supply to cardiac muscle precipitates pain.

Precipitating factors:

Anxiety, stress, exertion, strong emotions, heavy meal, and extreme weather conditions.

#### **Signs and Symptoms:**

If you are looking for typical symptoms of chest pain, you may miss some cases. List of all possible presentations being:

#### **Management:**

Simple angina should resolve very quickly with rest alone or with sublingual glyceryl trinitrate spray or tablets. In simple angina, the cardiac output is not impaired, and pulse should be regular. In a patient with chest pain, having an irregular pulse, suspect MI.

#### **4.6.2 Myocardial Infarction (Heart Attack)**

Progressive/Sudden ischemia of the cardiac muscle leads to necrosis of cardiac muscle. This can cause cardiac arrest.

#### **Signs and Symptoms:**

#### **Management:**

	- Establish IV access.
	- Give antiemetic Metoclopramide hydrochloride by IV [13].

Adult > 60 kg, dose 10 mg

Small-sized Adult <60 kg, dose 5 mg

– Administer analgesia - Paracetamol by slow IV (Morphine, diamorphine 7 fentanyl, are not easily available in India) [13].

Adult >50 kg, dose 1000 mg in 100 mL Small-sized Adult <50 kg, dose 750 mg in 75 mL When no IV access, alternatively, give Oral Paracetamol 650 mg

	- Watch for signs of cardiac arrest.
	- Start CPR, if cardiac arrest occurs.

#### **Box 4.7**

Drugs for MI:

Glyceryl Trinitrate Aerosol Spray: 400 μg/metered dose

Glyceryl Trinitrate: 300-μg tablets Soluble Aspirin: 300-mg tablets Metoclopromide: 10-mg solution for IV Paracetamol: 1000-mg/100-mL solution for IV Paracetamol: 500-mg tablets Paracetamol 650 mg tablets

#### **4.7 Cardiac Arrest**

Cardiac arrest is a sudden loss of heart function resulting in hypoxic damage to body organs. Lack of oxygen to the brain causes loss of consciousness, victim falls to the ground and stops breathing. Cardiac arrest can occur suddenly with or without any symptoms.

Following cardiac arrest neurons start to die within 4–6 min without oxygen. Chances of survival can be increased by early defbrillation (where indicated) and good-quality Cardiopulmonary Resuscitation, that's instituted quickly and performed with minimal interruptions. Automated External Defbrillators (AED) are increasingly available and these can analyze the rhythm, whether it's shockable or not and can suggest you through the process of CPR by voice commands. In centers where AEDs are not available, CPR is continued until appropriate help arrives. Often, in busy countries like India, this can take quite a considerable amount of time, so hospitals and healthcare establishments should be encouraged to buy AEDs.

Recognition of cardiac arrest:

	- Some people may have a seizure when cardiac arrest occurs as a result of severe cerebral hypoxia.

#### **Box 4.8**

Chest pain in a patient with previous history of stable angina: Urgent transfer to appropriate medical facility is to be done, if the patient feels the pain is unusual or if the pain doesn't resolve with rest and Sublingual Glyceryl Trinitrate.

#### **Box 4.9**

Do not waste time, for example, trying to fnd a vein while the ambulance is waiting! Antiplatelet medication (aspirin) within few minutes of suspecting MI and early thrombolysis by the Physicians can signifcantly reduce the mortality associated.

#### **Management:**

	- CPR can be executed in the dental chair.
	- Second person checks airway, gets ready for ventilations, preferably using a bag valve mask.
	- Nonshockable rhythm observed by AED—continue CPR until signs of life or AED starts analyzing rhythm again [16].
	- Shock advised by AED—Make sure no one touches the patient directly or indirectly—Deliver the shock.

#### **Fig. 4.1** Chain of survival

To improve overall outcome in cardiac arrest patients, it is necessary to follow these four important aspects of care:

The four points are incorporated into this internationally recognized "chain of survival," which is given here (adapted from the Resuscitation Council UK; website: https://www. resus.org.uk/EasysiteWeb/getresource.axd?AssetID=3907& type=Full&servicetype=Attachment) (Fig. 4.1):

#### **Box 4.10**

All healthcare workers should undergo proper training in CPR. Healthcare organizations throughout the world are now insisting on a CPR certifcate. Such a training has to be done on a periodic basis so that the skills are retained. The reader is strongly advised to undergo training periodically and a valid certifcate will prevent you from future litigation if an unfortunate event occurs to one of your patients.

#### **4.8 Hypoglycemia**

Glucose is essential for the effective functioning of neurons. When the glucose levels in blood drop to a very low level, brain function will get affected and if the glucose levels are not restored quickly, permanent neurologic damage can occur within 4–6 min. Hypoglycemia can occur in diabetic patients taking Insulin, who skipped meal, and is also the leading cause of loss of consciousness in children. Hypoglycemia occurs when blood glucose level falls below 70 mg/dL.

#### **Signs and Symptoms:**

	- Nausea and vomiting
	- Hungry
	- Visual disturbances
	- Convulsions
	- Loss of consciousness.

#### **Management** [17]:

Management depends on consciousness level and the ability of the patient to take food orally without the risk of aspiration.

	- 10–20 g of glucose

10 g of glucose in two teaspoons of granulated sugar Two teaspoons of Glucon-D powder contain 15 g of Glucose

	- Check if airway is clear—ABCDE approach
	- Put patient in recovery position
	- Oxygen supplementation at 15 L/min

Arrange for emergency transfer of patient Give 100 mL of 10% dextrose by IV route

Severe cases of hypoglycemia need 50 mL of 50% Dextrose

Higher concentrations of dextrose are thicker solutions, need a larger bore cannula.

Once the patient regains consciousness, give oral glucose and carbohydrate as earlier.

#### **Box 4.11**

Glucagon either by IM or SC route

Dose: Adult—1 mg

Child under 8 years or less than 25 kg should be given 500 μg (0.5 mg)

Keep patient in lateral position to prevent risk of aspiration

#### **4.9 Grand Mal Seizures**

Enquire with patients about how frequently they get seizures and their compliance with medication. Patients with frequent seizure history or patients who are irregular with their medications are more likely to have a seizure while having dental procedures. Provide the treatment in a calm, stress-free environment, avoid any seizure-triggering factors.

#### **Signs and Symptoms:**

#### **Treatment** [18]:

	- Remove all the sharps away
	- Create safe space around a ftting patient
	- Provide cushions like a pillow or blanket
	- Pay particular attention to head
	- Provide reassurance and empathy to the patient
	- Explain what had happened
	- Examine the mouth for any fuids and use suction
	- Examine for any bleeding, lacerations of tongue secondary to biting
	- Place the patient in a recovery position
	- Examine for any other injuries
	- Provide oxygen as required
	- Stay with the patient until the patient is fully recovered
	- Do not give anything orally until the patient is fully conscious, to avoid the risk of aspiration
	- Do not attempt to arouse a patient who is sleeping after a convulsive episode
	- Make arrangements for urgent transfer to appropriate medical center
	- Administer midazolam intravenously [21]
	- Where IV access is not possible:
		- Rectal route can be used effectively, especially in children.
		- Buccal midazolam gel can be instilled into buccal vestibule with the help of a syringe with no needle. Midazolam sprays, which can be used via nasal route, are slowly being available in India.
		- Buccal and nasal routes are increasingly being used and the reader is advised to look up for more up-todate information as suitable formulations are not routinely available in India.

#### **Box 4.12**

Midazolam Dosage:

Child: 0.1–0.2 mg/kg, not to exceed 10 mg in total Nasal Spray: Child: 0.2 mg/kg body weight (Max: 5 mg/nares)

Rectal: Adult and children above 12 years: 10–20 mg, can be repeated once after 10–15 min if needed

Child 2–11 years: 5–10 mg, can be repeated once after 10–15 min

#### **Box 4.13**

Remember generalized tonic-clonic seizures can be seen in:

#### **Box 4.14**

Midazolam is a benzodiazepine that carries the risk of respiratory depression. Patients need close monitoring after drug administration and may need respiratory support.

#### **Box 4.15**

Typical grand mal seizure, in a known epileptic patient, where the seizure has subsided within a couple of minutes, patient can be discharged with the carer, provided all the vital signs are with in normal range. Urgent hospital transfer is indicated in all other epileptic seizures.

### **4.10 Syncope**

Energy demands of the brain are met primarily by oxidation of glucose. A regular and constant supply of glucose and oxygen is essential for brain function. Supply of both glucose and oxygen depends on effective perfusion of the brain. When brain perfusion decreases beyond a critical level, the patient loses consciousness and the balance gets affected and the patient falls.

#### **Signs and Symptoms:**

#### **Management** [22]:

#### **4.11 Other Causes of Loss of Consciousness**

Although syncope is the most common cause of loss of consciousness, the other causes should also be borne in mind, as some of them can be quite serious, such as:

#### **Postural Hypotension:**

#### **Hyperventilation:**

Excessive breathing in an anxiety state or excessive crying resulting in drop of blood CO2 level.

#### **4.12 Conclusion**

Preparedness for emergency is the key and when you are prepared, emergencies are easier to manage. The maxillofacial surgeon should be able to recognize these conditions and initiate appropriate management before professional emergency help is available. More often, maxillofacial surgeon is the lone clinician and is the sole responder in an emergency. It is prudent for the surgeon to know what to do and what not to do to get the best out of the worst scenario or situation.

It is imperative that the maxillofacial surgeons thoroughly understand the pathophysiology and extend their skills to recognize and manage expeditiously and effectively the emergencies that may arise. It is advisable that the contemporary clinicians update their knowledge and skills periodically with proper training courses.

Protocols given here are based on the currently available evidence, keeping in view of the local healthcare systems and access. As protocols are only suggestive, the clinician is strongly advised to use his or her own discretion when dealing with medical emergencies (Table 4.1; Flowchart 4.1).

**Table 4.1** Causes of loss of consciousness and its age distribution

**Flowchart 4.1** Management algorithm for a collapsed patient where the cause of collapse is not known

#### **References**

**Open Access** This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons. org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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**Part III**

**Anesthesia for Oral and Maxillofacial Surgery**

## **Local Anesthesia in Oral and Maxillofacial Surgery**

Reena Rachel John

#### **5.1 Introduction**

Pain, the dreaded symptom, is an unpleasant sensation that draws the attention of the individual as a whole. Its management has greatly evolved in the feld of dentistry, starting from the leaves of a coca tree to articaine, Comfort Control Syringe (CCS) system, Transcutaneous Electrical Nerve Stimulation (TENS), Computer-Controlled Local Anesthetic Delivery System as well as oral and intravenous sedatives. Apart from all these, local anesthesia (LA) is the favored mode of pain control in the profession. The painless surgery under LA is must; otherwise, endogenous catecholamines are released if there is excessive pain during dental treatment, which can alter the hemodynamic status such as an increase in blood pressure and heart rate and even dysrhythmias [1].

#### **5.1.1 Historical Background**

The frst local anesthetic isolated from the leaves of a coca tree in 1860 by Neiman was cocaine, and it was Karl Koller in 1884 who showed the anesthetic effect of Cocaine. In 1905, Einhorn popularized Procaine as an effective local anesthetic. It was derived from benzoic acid and diethyl amino ethanol. In 1948, the anesthetic property of lignocaine was discovered by Lofgren, and T. Gordh applied it in dental surgery [2].

#### **5.1.2 Defnition**

Local anesthesia is defned as a reversible loss of sensation in the circumscribed area of the body caused by depression of excitation in the nerve endings or inhibition of the conduction process in peripheral nerves [2].

### **5.1.3 Ideal Characteristic of Local Anesthesia**

An ideal local anesthetic must have the following characteristics:

### **5.2 Classifcation** (Tables 5.1 and 5.2)

**Table 5.1** Classifcation of local anesthetic agents: based on chemical structure

R. R. John (\*)

Department of Oral and Maxillofacial Surgery,

**5**

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 61 K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_5

Vinayaka Mission's Sankarachariar Dental College and Hospital, VMRF DU, Salem, India

**Table 5.2** Classifcation of local anesthetic agents: based on duration of action

#### **5.3 Local Anesthetic Agents**

The LA agents have been divided into Esters and Amides groups. The commonly used Amides are Lidocaine, Articaine, and Bupivacain [2].

#### **5.3.1 Lidocaine (Lignocaine)**

Lofgren in 1943 introduced the prototype amide local anesthetic [2], i.e., Lidocaine.

The other similar names are xylocaine, octocaine, dentocaine. Chemically, it is Diethyl 2, 6 dimethyl acetanilide. The maximum recommended dosage for Lignocaine with vasoconstrictor is 7 mg/kg not exceeding 500 mg and without vasoconstrictor is 4.4 mg/kg not exceeding 300 mg. Its onset of action is 2–3 min and duration of action with vasoconstrictor is 45–75 min, without vasoconstrictor is less than 30 min. Its contraindications include Ehlers Danlos syndrome and Attention-defcit hyperactive syndrome. Lignocaine is available in the form of jelly, spray, patches, and ointments. The toxicity arises from inadvertent intravascular administration or from overdose.

Recently, Howlader et al. [3] suggested open reduction and internal fxation (ORIF) of isolated subcondylar fractures under local anesthesia by using 2% lidocaine with 1:200,000 epinephrine for mandibular nerve block and superior cervical plexus blocks (SCPB).

To anesthetize the cutaneous branches of SCP (lesser occipital, greater auricular, transverse cervical, and supraclavicular nerve), the solution is deposited at the midpoint of the posterior border of sternocleidomastoid muscle border, as well as inferior and superior to that point subcutaneously creating a feld block.

The anesthetic agent selection should be based on three main clinical considerations: anesthetic potency and latency, onset, and duration. The composition of the local anesthetic solution is shown in Table 5.3.

R. R. John

**Table 5.3** Composition of local anaesthetic solution (Lignocaine with Adrenaline)

#### **5.3.2 Bupivacaine**

Its chemical name is 1 butyl-2,6piperoloxylidine hydrochloride.

It is four times more potent than prilocaine, lidocaine, and mepivacaine. It is less toxic than lidocaine and mepivacaine and it is metabolized in the liver by amidases and excretion via kidney 16% unchanged. Its onset of action is similar to lidocaine, mepivacaine, and prilocaine. Effective dental concentration is 0.5% and anesthetic half-life is 2.5 h.

Maximum recommended dose is 1.3 mg/kg body wt to a maximum of 90 mg. Because of its long duration of action, it is advisable for use in lengthy surgical procedure and the management of postoperative pain. Hence, the patient's requirement for postoperative opioid analgesics is lessened when bupivacaine is used. Bupivacaine is not recommended in young patients as the risk of self-mutilation is increased.

The duration of soft-tissue anesthesia has been consistently shown to be longer than with lidocaine [4] and thereby reducing postoperative pain experience [5].

#### **5.3.3 Articaine**

Its chemical structure is 3-N Propylaminoproprionylamino 2-Carbomethoxy 4-Methylthiophene hydrochloride.

The potency of Articaine is 1.5 times more than lignocaine and 1.9 times than procaine. Its onset of action when used with vasoconstrictor is 1–2 min. Half-life is approximately 21 min and it is metabolized to pharmacologically inactive metabolite called articaine acid glucoronide. Since it is rapidly biotransformed to its inactive metabolite, it is a safe local anesthetic agent. It is excreted via kidney

**Table 5.4** Maximum recommended dose of common Local Anesthetic used

unchanged (5–10%) and as metabolite (90%). The maximum recommended dosage for articaine is 0.8 mg/kg body weight.

Contraindications for the use of articaine are Idiopathic or congenital methemoglobinuria, hemoglobinopathies, hypoxia, and in patients with cardio-respiratory failures. Prolonged paraesthesia has been reported as a complication following inferior alveolar nerve block (IANB) [6].

Articaine with epinephrine is the best choice to improve anesthesia in both infamed and in uninfamed tissues with good results, and more effective anesthesia for longer duration can be achieved [7]. Table 5.4 shows maximum recommended dose of commonly used LA.

#### **5.4 Vasoconstrictors**

Importance of vasoconstrictors in local anesthetic solution include

Most commonly used vasoconstrictors are epinephrine, norepinephrine, levonordefrin hydrochloride, phenylephrine hydrochloride.

#### **5.4.1 Dilution of Vasoconstrictor**

The explanation of 1:1000 vasoconstrictor concentration is that 1 g/1000 mg of solute is present in 1000 ml of the solution, which means 1 mg of solute in 1 ml of solution. In the local anesthetic solution, the concentration of vasoconstrictor is less. The concentrations used are 1:80,000 or 1:100,000 or 1:200,000. The concentration of 1:100,000 of the vasoconstrictor would contain 1000 mg in 100,000 ml of the solution. Therefore, 1 ml of 1:100,000 concentration would contain 0.01 mg in 1 ml.

**Table 5.5** Quantity of vasoconstrictor with varying dilutions

The absorption of vasoconstrictors is dose dependent and may last from minutes to half an hour. The patients with cardiovascular compromise are at increased risk with endogenously released epinephrine in response to stress rather than the epinephrine, which is injected with the local anesthetic (Table 5.5).

#### **5.5 Causes of Failure of LA**

#### **5.6 LA Toxicity and Antidote for Toxicity**

Symptoms, which refect toxicity from the administration of local anesthetic solution, may range from mild cutaneous reactions to severe life-threatening anaphylactic reactions. There are a variety of methods and drugs to treat these reactions symptomatically. However, the reversal of toxicity, including damage to vital organs such as the heart and brain, is still less understood. A clinically effcient antidote for a complete reversal of toxicity is still beyond our grasp currently.

#### **5.6.1 Reversal of Cardiomyotoxicity**

Intravenous lipid emulsion (IVLE) is being reported as a rescue measure for LA toxicity. This has been studied and proven in both animal models and in limited human trials with successful resuscitation outcomes. The lipid emulsion acts on the plasma and tissue and extracts the lipophilic anesthetic molecules, thereby reversing their inhibitory myocardial effects. Bolus doses of 1.2–2 ml/kg followed by continuous infusion of 0.25–0.5 ml/kg/min are currently advocated for adequate effcacy. This drug needs to be used judiciously as optimal dosages have not been established and the risks of overdosage are not clearly understood.

#### **5.7 Reversal of Soft-Tissue Anesthesia**

The duration of soft-tissue anesthesia often exceeds that of pulpal or bony anesthesia. This is an important reason for the occurrence of undesirable events like accidental lip or tongue biting, diffculties in speaking, eating, or drinking liquids, etc. Various drugs have been studied to decrease the postoperative duration of anesthesia. Of the various drugs tried clinically, phentolamine is one drug, which has demonstrated appreciable clinical effcacy.

Phentolamine is a nonselective alpha-adrenergic antagonist that is reversible. Its main action is vasodilatation. It has been used effectively for controlling hypertensive emergencies, especially in pheochromocytomas. In dental practice, Phentolamine in the form of phentolamine mesylate injections has been used as a reversal agent against LA by reversing the action of vasoconstrictors in the LA solution and expedites the metabolism of the LA molecules. The recommended dose for phentolamine is the administration of 1.8 ml of the solution containing 0.4 mg of phentolamine mesylate immediately after treatment.

#### **5.8 Plain Local Anesthetic (Without Epinephrine)**

It is preferred for patients having comorbidities such as circulatory disorder to avoid complications and adverse systemic effects of vasoconstrictors [8]. Lip laceration is one of the common cases, which are attended to by a maxillofacial surgeon in the emergency department for suturing. Localized blanching caused by the use of local anesthetic with adrenalin at the lacerated wound causes diffculty in locating the exact demarcation between skin, white roll, and lip. Therefore, LA without epinephrine is preferred in such cases before suturing [9].

#### **5.9 Topical Local Anesthetic Agent**

The solution used for this purpose is 5% Lignocaine, 10% Lignocaine, combination of 2.5% lignocaine and 2.5% prilocaine [10]. They are indicated in patients [11, 12]

In suture and staple removal

#### **5.10 Surface Anesthesia**

The form of drug used to obtain this includes ointment, gel, viscous, cream, spray, etc. Topical application of these forms can produce anesthesia on the surface, particularly of the oral mucosa.

This is used often, before an actual injection for L.A, at the site of injection, in order to reduce the pain of the needle prick itself. It can also be used to obtund pain in situations where the oral mucosa is breached, as in an ulcer in the oral mucosa. The gel may also be used to anesthetize the surface mucosa, e.g., nasal, pharyngeal, etc., before a diagnostic endoscopy.

The concentration of a local anesthetic applied topically is typically greater than the same drug administered by injection. Drugs that are commonly employed in topical L.A formulations are Benzocaine and Lidocaine.

EMLA, which is a eutectic mixture of local anesthetic agents, lignocaine, & prilocaine in the ratio 1:1 by weight, has been found to be a very useful topical agent to be applied on the skin, before painful procedures like injection, venipuncture, etc. and is used extensively in children. This particular cream, which is oil-in-water emulsion, may also be used for surface anesthesia of the oral mucosa for purposes listed earlier.

#### **5.11 Methods of Local Anesthetic Administration**

There are major three different types of methods:

In local infltration, deposition of the local anesthetic solution in the area of the surgery to anesthetize small terminal nerve endings. Field block involves the deposition of anesthetic solution near the large terminal nerve branches to prevent the passage of impulses from teeth to the central nervous system. In nerve block, local anesthesia is deposited away from the site of surgery, but close to the main nerve trunk.

Different techniques for mandibular nerve block anesthesia have been published, including the mental/incisive nerve block [13–15].

	- standard approach for mandibular anteriors and soft tissue
	- anterior approach
	- extraoral approach

#### 5 Local Anesthesia in Oral and Maxillofacial Surgery

Different maxillary nerve block techniques have been described.

	- intraoral approach (bicuspid approach)
	- Bisecting approach (central incisor)
	- extraoral approach
	- nasal approach (1969)
	- High tuberosity approach
	- Greater palatine canal approach
	- nasal approach
	- lateral extraoral approach
	- suprazygomatic extraoral approach extraoral approach
	- anterior-lateral extraoral approach.

#### **5.11.1 Percentage of Blood Vessel Penetration During IANB**

During IANB, the intravenous injection of local anesthetic is very common. Frangiskos F et al. [16], in their study, found positive aspiration (the tip of the needle is in the blood vessel) 20% times. The positive aspiration was more commonly seen in young patient's age ranging from 9 to 19 years. To avoid systemic complications while giving local anesthesia, aspiration is must in each and every case.

### **5.11.2 Controversy in the Use of Bilateral IANB and Lingual Nerve Block** [17]

Has bilateral IAN and Lingual nerve block been given? Some surgeons recommend, while some do not, but there are no published data available regarding its contraindications. The common complications associated with its use are

Many authors advocated the use of sodium bicarbonate in addition to the lignocaine solution to reduce the duration of onset of anesthesia, and it is very effective in reducing pain during the injection. Sodium bicarbonate ions also nonspecifcally reduce the safety margin for nerve conduction and it has a direct action on the binding of Local anesthetic to the sodium channel [19–21].

#### **5.12 Techniques**

#### **5.12.1 Inferior Alveolar Nerve Block (***Also Known as* **Mandibular Nerve Block) [Along with Lingual & Long Buccal Nerve Blocks]**

This is the single most important nerve block, whose technique needs to be mastered. With this, we can anesthetize the whole of the mandibular soft and hard tissues, including the cheek, and many procedures in this region can be carried out.

Secondly unlike in the maxilla, infltration techniques do not provide adequate anesthesia to the hard tissue in the mandible, particularly the teeth. This is due to the dense cortical bone in the mandible, in contrast to the porous maxillary bone, where a paraperiosteal deposition of the solution can allow the solution to diffuse through the bone to the periapical region easily and cause anesthesia of the teeth and their supporting structures.

#### **5.12.2 Technique**

This description is for injection on the right side of the patient and for a right-handed operator. The surgeon is on the right side of the patient, in front of the patient. The patient is asked to open the mouth wide.

With the left hand, the operator palpates the posterior buccal sulcus, runs the index fnger posteriorly to feel the external oblique ridge and the anterior border of the coronoid process. As the fnger proceeds upwards, palpate the coronoid process up and down to determine the deepest point on its anterior border. This is the coronoid notch. [This is a very important landmark because this determines the vertical height at which the needle should be inserted, the reason being the Mandibular foramen on the medial aspect of the ramus where we want the needle to reach is in direct line with the coronoid notch] Fig. 5.1.

Once the coronoid notch is palpated with the pulp of the index fnger, the fnger is rotated such that the nail faces medially. At the same time, the fnger retracts the soft tissue

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.1** Dry mandible showing the position of needle and the coronoid notch

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.2** Picture showing needle insertion position from the soft tissue for IAN block

to reveal a depression called the pterygo mandibular depression, which is medial to the fnger between the fnger and the pterygo Mandibular raphe (Fig. 5.2).

Now the needle with solution in the syringe is taken in the right hand and is introduced into the mouth from the opposite side (i.e., left side) corner of the mouth/premolar area.

The syringe and needle are kept parallel to the Mandibular occlusal plane and are introduced into the pterygo temporal depression at the same height as the nail of the index fnger (on the coronoid notch). The needle is advanced slowly in the soft tissue till the needle strikes the bone and resistance is felt. Now the needle is in the pterygo mandibular space bounded laterally by the medial surface of the ramus of the mandible and it is just above the lingula in the area of the opening of the mandibular foramen.

The syringe is aspirated and 1 ml of the solution is deposited. This will anesthetize the inferior alveolar nerve as it enters the mandible. Now, the needle with the syringe is swung on to the corner of the mouth on the same side, i.e., right, and is slowly withdrawn after about half the length is inserted and 0.5–0.8 ml of the solution is deposited here. This will take care of the lingual nerve, which is anteromedial to the inferior alveolar nerve.

Now the needle is withdrawn completely out of the soft tissue and is reinserted into the cheek, posterior to the last molar teeth at the level of the occlusal plane of the mandibular teeth for a short distance. After aspiration, the remaining 0.5 ml of the solution is deposited. This anesthetizes the long buccal nerve [for the left-sided block, the surgeon is slightly behind the patient on the right side with the left hand coming around].

This classical Mandibular Nerve block of inferior alveolar nerve with lingual & long buccal is done together if the mandibular molars and their adjoining soft tissues need to be anaesthetized. The reason being the pulp and the periodontium of these teeth are supplied by the inferior alveolar nerve. The lingual gingiva is supplied by the lingual nerve and the buccal gingiva by the long buccal nerve.

#### **5.12.3 Areas Anesthetized by This Block**

	- (a) All mandibular teeth and the bone surrounding them.
	- (b) The buccal gingiva in relation to the Mandibular anterior and premolar teeth.
	- (c) Lower lip on the same half up to the midline.
	- (a) The lingual gingiva of the Mandibular teeth along with the lingual Mandibular mucosa.
	- (b) The Anterior 2/3rd of the tongue on the same side.
	- (a) The cheek mucosa.
	- (b) Buccal gingiva and mandibular mucosa in relation to the molar teeth.

#### **5.12.4 Signs and Symptoms of Anesthesia**

It usually takes about 3–5 min before adequate depth of anesthesia is obtained after any injection. In other words, although symptoms of anesthesia may be felt almost instantly after the injection, for the patient to feel no pain during the procedure a wait of at least 5 min is needed.

It has been conventional to confrm the anesthesia obtained with two parameters:

Subjective symptoms may or may not be present with certain nerve blocks, e.g., nasopalatine block. However with the classical inferior alveolar/mental nerve block, a *tingling and numbness* on one half of the lip (same side) will be felt. There will be an area of sharp demarcation between the numb side of the lip and the normal side at the midline. The tingling or numbness will start instantly to become heavy in about 3–5 min. Similar sensation of numbness will be felt on the same side of the tongue particularly the tip as a result of the lingual nerve block. There may be no symptoms of numbness felt by the patients in the other anaesthetized areas, e.g., the gingiva, teeth, or the cheek.

The objective sign as elicited by the surgeon is more reliable and may be the only means of ascertaining anesthesia in the absence of subjective symptoms. The objective sign of anesthesia is *lack of pain in the area anesthetized when stimulus is applied* with a blunt instrument, e.g., the end of a periosteal elevator. [It should be noted from the earlier discussion that the patient might feel the pressure of the instrument and an apprehensive patient might occasionally interpret this as pain.]

In checking for anesthesia of the inferior alveolar nerve, the blunt instrument must be applied on the buccal gingiva anterior to the mental foramen, because the lack of sensation in the posterior buccal soft tissue indicates a successful long buccal nerve and not inferior alveolar nerve block. The same blunt instrument must be applied in the gingival sulcus on the lingual side of the tooth to be extracted for lingual nerve anesthesia. The same can be done to check the buccal nerve anesthesia.

#### **5.12.5 Complications** (Table 5.6)

These were discussed very briefy as local complications of L.A in the earlier section. Specifc complications after an Inferior Alveolar Nerve block include:

#### **<IP_ADDRESS> Failure to Obtain Anesthesia**

It is the most common problem and usually due to the wrong technique. Repeating the block employing the right technique is usually the solution. However, this might be encountered in two other situations.

#### **<IP_ADDRESS> Hematoma Formation**

This may occur within the pterygo mandibular space as a result of bleeding induced by the needle prick. It may be a rare problem. The patient might have pain, swelling, & diffculty in opening the mouth. The treatment is symptomatic and possibly prophylactic antibiotic cover. It will resolve spontaneously.

#### **<IP_ADDRESS> Transient Facial Nerve Palsy**

May occasionally occur as a result of a faulty technique where the needle is inserted farther posteriorly into the substance of the parotid gland (in this situation, the needle would have failed to encounter bony resistance) and paralyzes the facial nerve.

The patient will have typical signs of ipsilateral facial nerve palsy/weakness, which includes diffculty in closing the eye, absence of wrinkles on the forehead, and drooping of the corner of the mouth ipsilaterally with a possible asymmetry. This effect will be transient, till such time the local anesthetic effect persists (about 1–1½ h) and the patient needs to be reassured.

#### **<IP_ADDRESS> Trismus**

Is a relatively more common complication and will be seen usually postoperatively. It could be due to a variety of causes, including:

Most of the time it resolves spontaneously. But on occasion, this will require anti-infammatory analgesics, muscle relaxants, and vigorous physiotherapy to overcome the problem. Wherever an infection is suspected, a suitable antibiotic cover may also be needed.

#### **<IP_ADDRESS> Accidental Breakage of the Needle**

Occurring within the tissues of the pterygo mandibular space, this is a very rare complication today where we use disposable needles for one use only. But when this happens, a radiographic guided exploration and removal of the broken piece may be needed. Gerbino G et al. [22] advocated use of brain LAB vector vision neuronavigation system for the retrieval of broken needle. This Intraoperative navigation system is very helpful in locating the broken needle fragment.

#### **5.13 Vazirani–Akinosi (VA) Versus Inferior Alveolar Nerve Block**

The closed mouth VA technique to anesthetize the IAN, lingual, and long buccal nerve simultaneously was described in 1977 [23]. VA is used only secondarily to conventional IAN block.

#### **5.13.1 Indications for VA** [24]

The percentage of Positive aspiration is much higher with IAN block in comparison to VA. This is because of the close proximity of the inferior alveolar artery, which enters the mandibular foramen just behind the nerve [25]. To avoid frequent aspiration, many surgeons prefer VA technique in normal patients also.

#### **5.13.2 Akinosi–Vazirani Technique (Closed-Mouth Technique)**

A 25-gauge long needle is used. The operator is in front of the patient on the right side (right-handed operator) for both sides on the patient.

With the left index fnger or thumb, the coronoid notch is palpated and the soft tissues on the medial aspect of the ramus are pushed laterally. The needle is held parallel to the maxillary occlusal plane on the same side of the injection and is inserted adjacent to the maxillary third molar into the soft tissue overlying the medial border of the ramus, just adjacent to the maxillary tuberosity. This is now advanced posteriorly & slightly laterally. The bevel of the needle is away from the mandibular ramus and in an average-sized adult the needle is inserted about 25 mm into the tissue. At this point, the tip of the needle will be in the middle of the pterygo mandibular space close to the branches of the mandibular nerve. After aspiration, the LA solution is injected.

The areas anesthetized, signs and symptoms of anesthesia are similar to the open-mouth technique of mandibular nerve block.

Another viable alternative to the VA block is the technique of Gow-Gates described in 1973. In the Gow-Gates technique, anesthesia is administered more proximally, at the neck of the condyle and relies on extraoral landmark [26].

#### **5.13.3 Technique**

A 25-gauge long needle is used. The operator stands in front of the patient. It is very essential for the patient to extend his neck & open the mouth as wide as possible. Here the needle is inserted into the mucosa medial to the mandibular ramus on a line parallel to a line drawn from the intertragic notch to the corner of the mouth—just distal to the maxillary second molar. The needle is inserted from the corner of the mouth on the opposite side. The height of insertion is just at the level of the mesiolingual cusp of the maxillary second molar. Slowly advance the needle till the bone is contacted. (The needle here is in contact with the neck of the condyle. The position the patient is asked to assume, i.e., extend neck & open mouth wide, is to facilitate a more frontal position of the condyle closer to the mandibular nerve trunk). The average depth of insertion is about 25 mm. Aspirate & inject 2 ml of the solution slowly. Unlike with the classical method, injection is at one site only in this technique. This anesthetizes the inferior alveolar, lingual, long buccal branches of the mandibular here with similar effect as the classical block (Fig. 5.3a, b).

#### **5.14 Mental/Incisive Nerve Block**

These are two very similar blocks except that in a mental block the solution is deposited around the mental nerve as it exits the mandible at the mental foramen, whereas for an incisive nerve block, the solution is injected into the mandible through the mental foramen. This blocks the incisive nerve, which is the continuation of the inferior alveolar nerve anteriorly, up to the midline.

#### **5.14.1 Technique**

This may be carried out with the operator standing in front of the patient (can also be done easily with the operator standing behind).

With the left-hand thumb or index fnger, palpate the mucobuccal fold on the mandible starting in the molar region moving anteriorly when depression will be felt. This is usually in relation to the apex of the premolar teeth where the mental foramen is present. The needle is now directed vertically to be inserted into this area with the bevel facing the bone. With the mental nerve block, the solution is deposited in the soft tissues, whereas for the incisive the needle is inserted into the foramen for a short distance before injection.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.3** (**a**, **b**) Position of needle from medial and lateral aspect in case of closed-mouth technique

#### **5.14.2 Areas Anesthetized**

#### **5.14.3 Signs and Symptoms**

#### **5.15 Nerve Blocks in the Maxilla**

As already mentioned, in maxilla buccal & palatal infltration techniques are often followed because they are effective, particularly if the surgical area is limited, e.g., extraction of a single tooth. However nerve blocks are useful at times, particularly when anesthesia of a larger area is sought.

#### **5.15.1 Posterior Superior Alveolar Nerve Block Technique**

The position of the operator is on the front of the patient for both sides, on the right side, for a right-handed operator.

Palpate the maxillary mucobuccal fold after asking the patient to open mouth partially and retracting the buccal soft tissue with the index fnger of the left hand. Insert the needle (25/27 gauge— 20-mm length) into the height of the mucobuccal fold opposite the upper second (second) molar tooth. Advance the needle in inward, upward, backward direction with the needle at 45° angle to the maxillary plane for about 10–15 mm. The tip of the needle will now be close to the entry of the posterior superior alveolar nerve into the maxilla on its posterior surface. Inject 1–1.5 ml of the solution after aspiration (Fig. 5.4).

#### **<IP_ADDRESS> Areas Anesthetized**

Hence, this is a nerve block, which may be used if multiple extractions of molar teeth have to be done in the maxilla or any other procedure in this area.

#### **<IP_ADDRESS> Signs and Symptoms**

*Subjective*: The patient usually will not feel any tingling or numbness in this case.

*Objective*: Lack of pain on probing with the blunt instrument as with any other local anesthetic injection.

*Complications*: Most common problem is a swiftly developing hematoma particularly if the needle goes too far distally into the area of the pterygoid venous plexus.

As in earlier instances, pressure needs to be applied in this case, on the face above the area where the swelling is developing. The sudden swelling can be alarming but is of little consequence once the application of pressure stops fows.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.4** Needle insertion position in posterior superior alveolar nerve block

Once again, reassurance to the patient is needed. Prophylactic antibiotics to prevent secondary infection of the hematoma may be considered.

#### **5.15.2 Infraorbital Nerve Block [Also Anterior and Middle Superior Nerve Blocks]**

#### **<IP_ADDRESS> Technique**

The operator (right handed) is on the right side of the patient for both sides, i.e., left & right.

With the left index fnger, the infraorbital rim on the face is palpated. A notch is felt on the medial third of this region, the fnger is now slid down to feel for depression below this notch on the anterior surface of the maxilla. This is the position of the infraorbital foramen. With the left index fnger over the infraorbital foramen, the cheek is retracted with the thumb and a 25-gauge needle is inserted intraorally into the height of the mucobuccal fold opposite the frst premolar with the bevel of the needle directed toward the bone and the needle being parallel to the long axis of the tooth. The needle is advanced until gentle bone contact is made, and this will be the upper rim of the infraorbital foramen.

Aspirate and inject about 1–1.5 ml of the solution. As the solution is deposited, frm pressure is applied over the infraorbital foramen by the left-hand index fnger so as to facilitate entry of the solution into the infraorbital canal through the foramen (Fig. 5.5a, b).

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.5** (**a**, **b**) Position of needle insertion and target point in dry skull in Infraorbital nerve block

#### **<IP_ADDRESS> Areas Anesthetized**

#### **<IP_ADDRESS> Signs and Symptoms of Anesthesia**

*Complication*: Are few. Rarely a hematoma may develop.

#### **5.15.3 Palatal Anesthesia**

Injection into the palatal tissues, whether an infltration or a nerve block, is the most painful. The reason is the palatal mucoperiostem is tightly adherent to the bone and there is no easy space for the solution to fow. This also makes the process of injection diffcult as often there is backfow due to the resistance offered.

Most often, particularly when a single tooth is involved, infltration anesthesia is preferred in the palate. However, two nerve blocks are often used particularly when a larger area is involved

#### **<IP_ADDRESS> Greater Palatine Nerve Block**

*Technique*: The greater palatine foramen in the adult is usually present on the palatal side of the second molar tooth at the junction of the alveolus and the horizontal palatine bone. (This may be palpated as a depression in this area but need not be done for the purpose of the nerve block.)

A 25/27-gauge short needle is inserted from the opposite side with the operator standing in front (for both sides of the patient) into the area palatal to the second molar at the junction of the alveolus & the palatine bone (Fig. 5.6a, b). A little solution is deposited (0.1–0.2 ml) at the point of entry and

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.6** (**a**, **b**) Intraoral and in dry skull showing insertion of needle in greater palatine nerve block

the needle is advanced into the foramen for a variable distance (0.5–0.7 cm) and the rest, about 0.8 ml is deposited. As *usual, always aspirate* before depositing any solution.

*Areas Anesthetized*: The palatal gingiva of the maxillary teeth till the second premolar on the same side as well as the palatal mucosa & bone on the same side till the premolar region.

#### **Signs and Symptoms of Anesthesia**

*Subjective*: May not always be there. However, numbness in the posterior hard palate mucosa may be present.

*Objective*: Confrmation of anesthesia is always by lack of pain in the area and tested by probing with a blunt instrument.

#### **<IP_ADDRESS> Nasopalatine Nerve Block**

*Technique*: Operator in front with the patient mouth wide open, a 25/27 gauge needle is inserted into the palate just lateral to the incisive papilla. A small amount 0.1–0.2 ml of the solution is injected after aspiration. Now the needle is advanced further into the incisive foramen for a distance of about 0.5–0.75 cm and 1 ml of the solution is deposited as always after aspiration.

*Areas Anesthetized*: Probably the only nerve block, which anesthetizes bilaterally symmetrical areas and hence there is no separate right- & left-sided blocks. The palatal gingiva of the anterior teeth up to the frst premolar on either side as well as the palatal mucosa and bone in the same anterior region.

#### **Signs and Symptoms**

*Subjective*: May be variable if present there is numbness of the anterior palate.

*Objective*: lack of pain in the anesthetized area on blunt probing.

The various nerve blocks discussed so far are the commonly used techniques. Usually this set of techniques is suffcient for all requirements of local anesthesia in the oral cavity. There are a number of alternative techniques, intraoral and extraoral, which are described in literature and may be popular in some parts of the world. However, a couple of them will be discussed here because they may have a specifc indication or may be a popular technique.

#### **5.16 Regional Blocks in Oral and Maxillofacial Surgery**

Regional blocks are fast becoming popular in providing not only local anesthetic support for performing surgical procedures of the head and neck, but also as a method for perioperative pain control in the form of pre-emptive anesthetic techniques.

This section focuses on a few regional blocks, which can be added to the armamentarium of today's maxillofacial surgeon.

#### **5.16.1 Maxillary Nerve Block**

There are numerous techniques for achieving total maxillary nerve anesthesia for dental and maxillofacial surgical procedures. These may be divided into intraoral and extraoral methods [27].

The intraoral techniques include:

*The extraoral technique* [28, 29]:

It involves a subzygomatic, technique. The clinical landmarks include the area below the zygomatic arch anterior to the articular eminence. This corresponds to the region above the midpoint of the sigmoid notch of the mandible. A 25-gauge 90-mm-long spinal needle is preferred for this method; the needle is inserted to a depth of about 45 mm till it contacts the lateral side of the lateral pterygoid plate. The needle is then withdrawn half-way and then angulated 15° in the forward and upward directions, which lead it to the region of the superior aspect of the ptm fssure, which corresponds to the exit of the maxillary nerve from the foramen rotundum across the ptm fssure. After negative aspiration, a volume of 2 ml is injected into the space, and the needle is withdrawn (Fig. 5.7).

#### **5.16.2 Mandibular Nerve Block**

The extraoral technique for the mandibular nerve block is very similar to the maxillary nerve block [30].

*Technique*—The surface landmarks and point of penetration for the block are the same and so is the armamentarium. The needle after penetrating the skin is advanced to

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.7** Representing pathway of needle in extraoral maxillary nerve block

contact the lateral pterygoid plate as described earlier, following which the needle is withdrawn half way and turned posteriorly by 15° to the same depth of 45 mm. This area corresponds to the region just caudal to the foramen ovale through which the mandibular nerve trunk exits the skull base. After negative aspiration, a volume of 2.5–3 ml is injected to anesthetize the mandibular nerve.

The extraoral mandibular nerve block with suprazygomatic access can be safely and effciently used with this unique approach for the mandibular nerve block to get relief in pain and Trismus. After local infltration, an 18-gauge insulated and stimulating cannula is inserted into the retrozygomatic space just above the zygomatic arch and directed to the angle of mandible with medial and posterior inclination (Fig. 5.8) [31].

#### **5.16.3 Greater Auricular Nerve Block**

This nerve block is performed as an extraoral technique and provides good surface anesthesia to the periauricular skin and skin over the angle of the mandible [32].

*Technique*—The landmarks used for this technique include the cricoid cartilage and the posterior border of the sternocleidomastoid muscle. With the patient supine or semisupine, a line is drawn from the cricoid cartilage to

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.8** Showing position of needle insertion in extraoral mandibular nerve block

intersect the posterior border of the sternomastoid muscle. This corresponds to the area where the superfcial branches of the cervical plexus emerge from under the sternomastoid muscle, wrapping around the posterior border. A small subcutaneous injection of local anesthetic solution (around 2 ml) will anesthetize the greater auricular nerve and its area of distribution (Fig. 5.9).

#### **5.16.4 Glossopharyngeal Nerve Block**

The utility of the glossopharyngeal block has been studied in indications such as:

*Technique*—A 25-gauge, 1 inch needle is chosen. The landmark for penetration is the base of the anterior tonsillar

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.9** Showing position of needle for greater auricular nerve block

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 5.10** Target area for glossopharyngeal nerve block

pillar lateral to the base of the tongue. The syringe is positioned with the barrel near the maxillary premolar of the contralateral side with the needle facing the base of the anterior tonsillar pillar. The tongue is retracted medially to provide good visualization of the involved site. The needle is then made to pierce the mucosa and advance by 5 mm. This corresponds to the target site for the glossopharyngeal nerve in the submucosal space. After judicious aspiration, if found negative, a volume of 3 ml of anesthetic solution (2% lignocaine) is administered to block the nerve trunk (Fig. 5.10).

#### R. R. John

#### **5.16.5 Sphenopalatine Ganglion Block**

Indications for sphenopalatine ganglion block include:

*Technique*—There are numerous techniques for the administration of sphenopalatine block, but the most commonly followed methods are the greater palatine approach and the transmucosal approach in the posterior aspect of the middle meatus. The greater palatine approach is the same as the maxillary nerve block via the greater palatine canal, which simultaneously blocks the sphenopalatine ganglion as well. The transmucosal method, which is most commonly followed, maybe done blind or using endoscopic guidance. A cotton pledget on a long application stick is dipped in anesthetic solution or gel and is advanced transnasally to the posterior aspect of the middle turbinate to reach the end of the middle meatus. This corresponds to the level of the sphenopalatine ganglion, which is a very superfcial structure. The local anesthetic gel is then deposited, which produces anesthesia through transmucosal perfusion. Another recent technique involves the submucosal injection of the anesthetic solution into the posterior aspect of the middle meatus for achieving the block (Fig. 5.11) [37].

#### **5.17 Recent Advances in Local Anesthesia**

Research is ongoing to fnd newer modalities of pain management. In order to administer local anesthesia with less pain and adverse effects, newer technologies have been developed. Some of them are:

#### **5.17.1 Vibrotactile Devices**

This device is based on the Gate Control theory, which proposes that pain during injection can be decreased by simultaneous stimulation of nerve fbers by vibration.

#### **<IP_ADDRESS> Vibraject** [38]

An attachment, which is battery operated, is snapped on to the barrel to deliver strong vibrations, which is felt by the patient and therefore reducing the perception of pain.

#### **<IP_ADDRESS> Dental Vibe** [39]

It is a handheld device, which delivers pulsed percussive oscillations to the site of injection, thereby closing the pain

©Association of Oral and Maxillofacial Surgeons of India

gate. It does not have a cord and it can be recharged. Dental vibe signifcantly lowered the self-reported pain during local anesthesia injections compared to a conventional approach.

#### **<IP_ADDRESS> Accupal**

It is a cordless device, which shuts the pain gate by preconditioning the site of injection by pressure and vibration. To energize the dental tissue in and around the site to be punctured by the needle, Accupal incorporates the "Pain Gate theory" [40].

### **5.17.2 C-CLAD (Computer-Controlled Local Anesthetic Delivery)**

With this device, there is a controlled delivery of the anesthetic and hence reduction of pain during injection. With this device, we can slowly administer anesthesia and control the injection speed [41].

#### **Advantages of C-CLAD device**

Higher success rates for single tooth anesthesia. The absence of pain especially in pediatric patient with disruptive behavior. More effective than a traditional syringe.

**Disadvantage**—Diffculty in locating the precise site for needle placement.

*C-CLAD* technology led to the development of an instrument for medical and dental injections capable of controlling all variables of subcutaneous injection event.

#### **5.17.3 Compu-Flo**

Allows instantaneous real-time measurement of fuid exit pressure at the tip of the needle. This approach to fuid exit pressure at the tip of the needle is called dynamic pressuresensing technology (DPS) technology.

#### **5.17.4 STA—single tooth anesthesia**

More predictable, reliable, comfortable anesthesia than highpressure mechanical syringe. The system incorporates the safety of using dynamic pressure-sensing technology allowing low-pressure administration of local anesthetic drugs. All patients receiving PDL with STA device reported subjective pain responses of minimal or no pain.

#### **5.17.5 Jet Injection**

The principle of Jet injection is that the mechanical energy is used to force a thin column of the local anesthetic solution through a small opening into the soft tissue under pressure without causing tissue damage. There is less or no pain during this procedure [42].

#### **5.17.6 MED-JET H III**

Local anesthetic solution in extremely small amount is administered under pressure through an orifce seven times smaller than the smallest available.

#### **5.17.7 Safety Dental Syringes** [43]

The protective sheath over the needle prevents accidental needle stick injury.

#### **Ultrasafety Plus XL Syringe**

The plunger, which is autoclavable and reusable, has a sterile disposable protective shield. It does not have to be disassembled prior to disposal.

#### **Ultrasafe Syringe**

Transparent disposable syringe with retractable needle sheath is helpful in aspiration and helps in seeing the aspirated contents in the syringe barrel.

#### **Hyposafety Syringe**

Disposable syringe and needle, which is translucent with a retractable needle into the barrel. Hence, less chance of needle stick injury. The main disadvantage is that the needle cannot be re-exposed to readminister the remaining solution.

#### **REV VAC Safety Syringe**

It is similar to the standard conventional syringe, the difference being that when the plunger reaches the bottom after all the medicine has been administered, further push on the plunger will cause breakage of the needle, which retracts into the plunger. It can be used only once.

#### **5.17.8 Devices for Intraosseous Anesthesia** [44]

#### **Stabident**

This device can be used with the armamentarium that is available in the clinic to administer the anesthetic solution. The main disadvantage is that inaccessible areas cannot be anesthetized with this equipment.

#### **X-Tip**

It is a single-step method. An initial drill is placed, which allows entry and withdrawal in one step during administration.

#### **5.18 Conclusion**

Pain is always a deterrent to seek treatment and hence local anesthesia is a boon to all clinicians and patients alike. Although the medication provides pain relief, its administration has always instilled fear in one and all. The advances in equipment and techniques of local anesthesia administration have undergone continuous research and development to make it as painless as possible.

#### **References**