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.

## **Management of Soft Tissue Injuries in the Maxillofacial Region**

**49**

Abhay Datarkar and Shikha Tayal

#### **49.1 Introduction**

Soft tissue injuries are one of the most commonly encountered injuries in head and neck region and present especially in the emergency department or surgical casualty. They can be isolated soft tissue injuries, or injuries having concomitant skeletal trauma. The frequent facial soft tissue injuries include simple lacerations, abrasions, contusions, bites, avulsions, and burns. These injuries are complicated by presence of vital anatomical structures like vessels, ducts, nerves, and muscles. Presence of foreign debris and hematoma further complicates the soft tissue injuries. The face is a region of high esthetics and functional importance. Hence, there are many factors that help to manage such injuries.

Factors that guide facial soft tissue injury management are:

Disclosure: Authors have no fnancial conficts to disclose.

primarily closed as soon as they are seen and as long as active infection is not present.

To achieve this, the surgeon needs to understand the etiopathogenesis, surgical anatomy, biomechanics of tissue wound, biology of wound healing, and the art of soft tissue repair.

#### **49.2 Etiology**

The most common etiology of facial soft tissue injuries varies according to the age, sex, and geographical distribution of the population. Facial soft tissue trauma tends to occur in certain areas of the head depending on the causative mechanism. It typically includes the T-shaped area that includes forehead, nose, lips, and chin, followed by the occiput and anterior temporal areas.

A. Datarkar (\*) · S. Tayal

Department of Oral and Maxillofacial Surgery, Government Dental College and Hospital, Medical College Premises, Nagpur, Maharashtra, India

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 997

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_49

### **49.3 Classifcation of Soft Tissue Injuries**

Soft tissue injuries can be classifed into multiple categories:

#### (A) **Based on mechanism of injuries**

	- When injury is caused due to blunt force:
	- 1. Incised wounds
	- 2. Chop wounds
	- 3. Stab/punctured wounds
	- Due to excessive cold: e.g., frostbite

#### (B) **Legal classifcation**

**Box 49.1 Classifcation of Soft Tissue Injuries**

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.1** (**a**) Showing open wound where fractured left clavicle is visible from the wound surface. (**b**) Open wound of maxillofacial region where underlying mandible is visible

#### (C) **Based on the communication of the injury with the external environment**

**Closed wound**: Only the underlying tissue and/or structures are damaged without breaking the skin. Examples of closed wounds include hematomas, contusions, and crush injuries. These types of wounds are not contaminated and, hence, heal on their own without any sequelae.

**Open wounds**: There is a break in the skin, which exposes the underlying structures to the external environment. Open wounds include simple and complex lacerations, avulsions, punctures, abrasions, accidental tattooing, and retained foreign body with a tendency to heal with scarring. These injuries require extensive exploration and debridement followed by a course of antibiotic regimen for uneventful healing (Fig. 49.1).

(D) **According to the facial subunit(s) involved**. The major esthetic subunits on the face are the scalp, forehead, nose, periorbital region, cheek, perioral region, auricle, and neck [4].

> These major facial esthetic subunits are further divided into smaller subunits by location. The individual subunits must be reconstructed individually one by one in order to attain good esthetics (Fig. 49.2).

	- (a) **Injuries to nerve**—The nerve injuries are most commonly encountered in cases of open wounds.

The nerve injuries are further classifed into neuropraxia, axonotmesis, and neurotmesis (Seddon's classifcation of nerve injuries [5]). Sunderland [6] further revised this classifcation of nerve injuries based on the histologic degree of nerve damage. There should be careful evaluation of sensory and motor components of the nerves in the involved region for proper treatment. The most commonly encountered nerve injuries in maxillofacial region are the facial nerve and trigeminal nerve.

#### (F) **Rank and Wakefeld classifcation** [7] **of wounds**

(a) **Tidy wounds**—The wounds that are inficted by sharp instruments like surgical blades and contain

A. Datarkar and S. Tayal

©Association of Oral and Maxillofacial Surgeons of India

no devitalized tissue are called tidy. These wounds are closed primarily. Examples are surgical incisions, cuts from glass, and knife wounds.

(b) **Untidy wounds**—Untidy wounds result from crushing, tearing, avulsion, vascular injury, or burns and contain devitalized tissue. Such wounds must be managed by wound excision. The devitalized tissue is excised, and the untidy wound is converted into the tidy wound before proper closure is achieved. The chances of infection are high if inadequately managed.

#### (G) **CDC classifcation of surgical wounds**

A **surgical wound** is a wound created by incisions and placement of drains during surgeries.

Surgical wounds can be classifed into four different categories depending on the bacterial load, the risk of infection, and where the wound is located on the body.

**Class I**: **Clean wounds**. They show no signs of infection or infammation. They often involve the eye, skin, or vascular system. It is often due to nonpenetrating (blunt) trauma.

**Class II**: **Clean-contaminated wounds**. Although the wound may not show signs of infection, it is at an increased risk of becoming infected because of its location. For example, surgical wounds in the respiratory tract like oropharynx and gastrointestinal tract may be at a high risk of becoming infected.

**Class III**: **Contaminated wound**. A surgical wound in which an outside object has come into contact with the skin and has a high risk of infection. For example, a gunshot wound may contaminate the skin around where the surgical repair occurs.

**Class IV**: **Dirty-contaminated or infected wounds**.

The wounds that have been exposed to fecal material and have a high bacterial load.

This wound classifcation guides in choosing appropriate treatment as well as helps in predicting post-repair form and function.

#### **49.3.1 Common Soft Tissue Injuries**

The common clinical presentation of soft tissue injuries included abrasions, contusions, and lacerations.

1. **Abrasions**—(also known as gravel rash) (Fig. 49.3)—It is destruction of the superfcial layer of skin only. It is caused by frictional forces that are light enough to erode only the superfcial layer of epidermis. It can be scratches

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.3** Showing multiple abrasions over face involving the supraorbital region, nose, upper lip, and chin

or linear type of abrasion, graze or sliding abrasion, pressure abrasions, and impact abrasions.

The healing of abrasions takes place from the periphery of the wound towards the center by new growth of epithelial cells. The wound is bright red in color for the frst 12–24 h due to extravasation of blood which dries up to form a red scab. After 2–3 days, a reddish-brown scab is formed. After 4–7 days, epithelium grows and covers the defect under the scab, which gives it a dark brown to brownish-black appearance. After 7 days, the scab dries and ultimately falls off, leaving depigmented bright pinkish area underneath, which attains its normal pigmentation gradually over a period.

2. **Contusions (bruising)** (Figs. 49.4 and 49.5)—This is effusion of blood into the tissues, due to the rupture of small blood vessels at the site of impact. There is no destruction of the superfcial layer of skin. The subtypes are (a) intradermal, (b) subcutaneous, and (c) deep.

A bruise heals by disintegration of extravasated blood. The red cells in the wound are hemolyzed, and the hemoglobin molecule is broken down into hemosiderin, hematoidin, and bilirubin by the action of enzymes.

This type of injury demonstrates a change in the color of the wound according to the time lapsed after injury: red at the time of injury, blue within few hours to 3 days, and

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.4** Showing contusion wound over right cheek and periorbital ecchymosis of the right eye. The color changes can be appreciated intraorally

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.5** Showing bilateral periorbital ecchymosis (raccoon eyes)

bluish-black to brown color due to deposition of hemosiderin from the extravasated RBCs, by the 4th day. In 5–6 days, the wound appears greenish due to disintegration of hemoglobin to hemosiderin. Between 7 and 12 days, the wound appears yellow due to the presence of bilirubin which is the fnal disintegrated product from hemoglobin. The wound appears normal by 2 weeks. The various factors affecting the color of contusion include the depth of the bleeding, amount of extravasated blood, and overlying skin color.

3. **Lacerations**—It is the tear or split of skin, mucous membrane, muscle, or internal organs produced by the application of blunt force to a broad surface area, which

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.6** Showing split lacerated wound over the nose, columella, lower lip, and chin

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.7** Cut laceration having sharp clean cut edges

crushed or stretched tissues beyond the limits of their elasticity. They can be split lacerations (Fig. 49.6), stretch lacerations, shearing lacerations, and cut lacerations (Fig. 49.7).

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.8** Showing incised wound extending from dorsum of the nose till pre-auricular region; caused by knife in a case of assault

object, such as knife, sword, chisel, scissors, nail, needle, spear, arrow, screw driver, etc. into the depths of the body. This type of wound is deeper than its length and width. These can be of the following types:

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.9** Showing penetrating wound. (**a**) Only the entry site is seen over the right temporal region. (**b**) The object remains dislodged within the body cavities

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.10** Showing gunshot wound injuries. (**a**) Picture showing entry wound over pre-auricular region. (**b**) Showing exit wound over right infraorbital region on opposite side

9. **Burn injuries**—Burns are injuries to tissues caused by heat, friction, electricity, radiation, or chemicals. Most burns are from hot objects (including fuids) and fre. Burns cause severe skin damage where the cells die. Burns are highly painful injuries which require specifc treatment as distinct from other injuries depending on the degree of burn.

The clinical presentation of burns depends largely on the depth of injury. Superfcial burns (frst degree) are confned to the epidermis. They are characterized by severe pain, dryness, and redness of skin. Superfcial partialthickness (second degree) burns extend into the papillary dermis. The skin is moist and red and blanches with pressure. Blisters are common in this type of injury. Deep partial-thickness burns extend into the reticular dermis. The skin is dry and appears yellow or white with minimal blistering. Full-thickness burns extending to the entire depth of dermis are classifed as 3rd degree. These are very severe injuries. The skin is stiff, leathery, and brown, but pain is not a common feature. Fourth-degree burns involve charring of skin and affect the deeper structures like fat and muscle. The skin is dry, black, and painless.

#### **49.4 Initial Evaluation and Assessment**

All trauma patients should be assessed and managed initially according to the principles of Advanced Trauma Life Support. Soft tissue injuries of the head and neck region can be accompanied by signifcant swelling and bleeding leading to airway compromise. The patient also should be assessed for associated ophthalmologic, intracranial, and cervical spine injuries.

#### **49.5 History and Examination**

Once the patient has been evaluated for life-threatening injuries and stabilized as necessary, a thorough and focused history and physical examination of the head and neck should be performed. History includes timing and mechanism of injury.

Early treatment of soft tissue injuries is associated with optimal esthetic outcomes. Determining the mechanism of injury may help the surgeon in managing the wounds with special consideration. For example, crush injuries may result in a larger area of compromised tissue than appreciated on initial examination. Tissue that appears healthy initially may subsequently necrose and may require serial debridement.

The site(s), depth, and nature of all wounds should be noted. Presence of nonviable tissue, gross contamination, and any foreign body like dirt and debris are important to discern.

Palpation helps to identify the presence of underlying bony injuries. Palpation can be done through the open wound itself.

#### **49.6 Management of Soft Tissue Injuries**

The principles of management of soft tissue injuries include the control of bleeding, copious irrigation of the wound, debridement of devitalized tissue, and removal of foreign bodies before closure.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.11** Showing wound excision and serial debridement of an extensive untidy wound gradually healing secondarily

excised using sharp scissors, and the wound margins are freshened up. The toilet of any wound should be done in a systematic layer-wise manner from superfcial to deep (Fig. 49.11).

(f) **Closure**—Ideally, facial soft tissue injuries should be closed as early as possible. Primary closure of a wound should be completed within 8 h of injury when possible [9]. Early intervention and closure decreases the risk of infection as well as optimizes the functional and cosmetic result. Basic principles of suturing should be met, which include precise approximation and eversion of the skin edges, avoidance of excessive tension, and layerwise closure to prevent dead space and fuid accumulation.

If gaping of the lacerated margins or tissue loss is present that cannot be closed primarily, the tissue can be managed by regular dressing and allowed to heal secondarily. Revision surgeries to improve esthetics and function are performed after minimum of 9 months.

(g) **Reconstruction** [10]—Done in cases of extensive degloving injuries. There are several options for soft tissue reconstruction using faps. Starting from local, regional, distant faps and free microvascular faps, depending on the type, location, and extent of the injury (Box 49.2).

#### **49.7 Wound Dressings**

Wound dressings are sterile pads used to cover the wounds. Lister [11] introduced antiseptic dressings by soaking gauze in carbolic acid. The dressings should be clean and provide a warm and moist environment for the successful wound healing. The dressings should be frequently changed in order to keep the wound free from bacterial load. Antibacterial ointments must be applied over the wound to keep it lubricated and free from bacteria. The dressings are selected on the basis of two concepts: occlusion and absorption. The reasons for placing a wound dressing are enumerated in Box 49.3.

#### **Box 49.3 Purposes of Dressings**

*Purposes of applying dressings over wounds*

*In selected cases, the dressing is modifed to achieve additional purposes such as*

Studies [12] have demonstrated that the rate of epithelialization under a moist occlusive dressing is twice that of a wound that is left uncovered and allowed to dry. An occlusive dressing provides a mildly acidic pH and low oxygen tension on the wound surface, which is conducive for fbroblast proliferation and formation of granulation tissue.

However, wounds that produce signifcant amounts of exudate or have high bacterial counts require a dressing that is absorptive and prevents maceration of the surrounding skin. These dressings also need to reduce the bacterial load while absorbing the exudate produced. Placement of a pure occlusive dressing without bactericidal properties would allow bacterial overgrowth and worsen the infection.

The various types of dressings [13] can be enumerated as in Table 49.1.

#### **49.8 Other Therapies**

1. **Hyperbaric oxygen therapy**—uses oxygen as a drug and the hyperbaric chamber as a delivery system to increase PO2 at the target area. It involves inhalation of 100% oxygen at 1.9–2.5 atm, for sessions of 90–120 min each. Treatments are given once daily, fve to six times per week and should be given as an adjunct to surgical or medical therapies. Clinical evidence of wound improvement should be noted after 15–20 treatments.

**Table 49.1** Types of wound dressing materials

**Mechanism of action**—HBO therapy can increase tissue PO2 ten times higher than usual. The higher PaO2 is suffcient to supply the tissue with all its metabolic requirements even in the absence of hemoglobin. This elevated level lasts for 2–4 h after termination of HBO therapy and induces synthesis of endothelial cell NO synthase as well as angiogenesis. Oxygen stimulates angiogenesis, enhances fbroblast and leukocyte function, and normalizes cutaneous microvascular refexes, thus aiding in healing of chronic, complicated, non-healing wounds.

2. **Negative pressure-assisted wound therapy**—Argenta [14] and associates originally described the use of negative pressure to assist in wound closure in 1997. By applying subatmospheric pressure to wounds, they demonstrated removal of chronic edema, an increase in local blood fow, and stimulation of granulation tissue. This technique may be used on acute, subacute, and chronic wounds. The wound is flled with a foam substance. A drainage tube is inserted into, or laid on, the foam, and the part is then covered with impermeable flm. Suction is applied at around 125 mmHg between changes of dressing.

#### **49.9 Necrotizing Fasciitis**

It is a rapidly spreading necrotizing soft tissue infection, also known as fesh-eating disease. It is one of the most challenging infections faced by the maxillofacial surgeons due to its diagnosis and management. The most common bacteria responsible for the fascial necrosis are hemolytic *Streptococcus* and *Staphylococcus*.

It is foul-smelling with loss of skin and superfcial subcutaneous tissue, having patchy blackish necrosis and frank pus along with the raw surface of the wound, margins of which are pale and spreading in nature. If it involves the skin of scrotum, it is known as Fournier's gangrene.

The prompt diagnosis and aggressive treatment is the key to manage this complicated condition. Removal of the offending factors like carious tooth and infected foreign material is the prime step followed by aggressive debridement and desloughing involving the normal tissue margins under the antibiotic coverage and adequate anesthesia. Once the wound is free of the active infection, showing healing margins with no evidence of pus, it is reconstructed with the skin grafts (Fig. 49.12).

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.12** Depicting a case of necrotizing fasciitis of the right side of the neck due to infection from right mandibular third molar. The patient was promptly and aggressively managed by sequential debridement followed by anterolateral thigh skin graft

#### **Table 49.2** Phases of wound healing

#### **49.10 Principles of Soft Tissue Healing**

The three phases of repair in soft tissue wounds are overlapping and include

Any alteration in the local environment of the wounds or the systemic status of the patients can infuence the normal process of wound healing.

#### **49.11 Types of Wound Healing**

The various types of wound healing include:

#### **Table 49.3** Factors that negatively infuence wound healing

3. **Secondary intention**—healing is by natural biologic processes without surgical intervention, and it usually occurs in large wounds associated with soft tissue loss or avulsion. It involves epithelialization and collagen deposition for wound healing. Contraction is the most important phenomenon in the spontaneous closure of large open wounds.

#### **49.12 Complications in Wound Healing**

Complications in the normal process of wound healing may occur due to presence of various local and systemic factors which exert a negative impact (Table 49.3).

One of the frequently observed complications is "abnormal wound healing" which presents in different forms such as keloids and hypertrophic scars. These are proliferative scars characterized by excessive net collagen deposition. Keloids and hypertrophic scars (Fig. 49.13) differ histologically from normal scars. The clinical appearance of the two types of scar is described in Table 49.4.

Keloids and hypertrophic scars contain collagen bundles aligned in the same plane as the epidermis. Tension

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 49.13** Showing. (**a**) keloid type of scar and (**b**) hypertrophic scar healing

over the edges of the wound signals the formation of activated fbroblasts resulting in excessive collagen deposition.

Scars perpendicular to the underlying muscle fibers tend to be flatter and narrower, with less collagen formation than when they are parallel to the underlying muscle fibers. As muscle fibers contract, the wound edges become reapproximated when they are perpendicular to the underlying muscle and tend to gape if placed parallel to it, leading to greater wound tension and scar formation.

#### **49.12.1 Prevention of Hypertrophic or Keloid Scars**

The four strategies that reduce adverse scarring immediately after wound closure are:

Postsurgical taping of the wound for 3 months can reduce scarring. Moisturizing lotions and moisture-retentive dressings (silicone sheets and gels) can reduce the thickness, discomfort, and itching and improve the appearance of the scar.

#### **49.13 Recent Advances in Soft Tissue Management**

They include—*Bioengineered Skin substitutes vis* [15]

(c) *Bilayer substitutes*—Integra, developed in 1981, was the frst acellular bilayer and has been used successfully to treat burns and chronic wound patients.

#### **49.14 Conclusion**

Proper assessment and classifcation of soft tissue injuries is the primary step in management. Early intervention and closure of soft tissue injuries is associated with optimal functional and esthetic outcomes as well as decreases the risk of complications. The basic principles of management of soft tissue injuries include the control of bleeding, copious irrigation of the wound, debridement of devitalized tissue, and removal of foreign bodies before closure. Administration of antibiotics and tetanus prophylaxis play a vital role in management of contaminated wounds. Wound dressings are mandatory to protect wounds postoperatively and facilitate ideal healing. Soft tissue injuries resulting in loss of tissue must be reconstructed using faps which may be local, regional, distant, or free microvascular faps, depending on the type, location, and extent of the injury. Innovative options such as growth factors, stem cell therapy, and bioengineered skin substitutes may be considered.

#### **49.15 Case Scenarios**

#### **Case Scenario 1**

A 23-year-old male patient met with a road traffc accident and suffered from a perforating injury over the nose, extending to right infra-orbital region. After initial resuscitating of the patient and ruling out the head injury component, the patient was taken up for the management of soft tissue and hard tissue injuries under general anesthesia. Through the existing lacerated wound, open reduction and internal fxation was done within 48 h of the trauma. Simultaneously, the soft tissue closure was performed layer-wise. Closure of the muscle layer was performed followed by the subcutaneous tissue and fnally the skin (Fig. 49.14a–e).

#### **Case Scenario 2**

A case scenario of a 67-year-old male patient who reported to the department of Oral and Maxillofacial Surgery. He was a victim of ballistic injury while he was working in a marketplace. The penetrating pathway of the bullet could be traced

**Fig. 49.14** Case scenario 1(a–e): Soft tissue management of a road traffc accident victim

having an entry site over left cheek. An extensive and careful exploration was performed in the OT under general anesthesia after the sections of 3D CT face were obtained (Fig. 49.15a–g). The comminuted fracture of the mandible was reconstructed using reconstruction plate. The bullet was found to be lodged in the carotid triangle just above the bifurcation of the common carotid artery.

Soft tissue management in such type of ballistic injuries becomes very critical. Since the bullet is a foreign material, it has to be removed from the soft tissues. The approach could either be through the entry wound but due to deep seating of the bullet into the neck and proximity of vital structures, one should always think of an extensive approach. The neck dissection was carried out in this case to remove the bullet from the bifurcation of common carotid artery in as atraumatic manner as possible. Bidigital palpation is a crucial step to locate the foreign body in this region. One interesting fact about such injuries is that though they are extensive with crushed and comminuted fractures and they are sterile due to the heat generated by the velocity of the bullet along its path. Such injuries are less prone to infection.

**Fig. 49.15** (a–g) Case Scenario 2: Soft tissue management in a ballistic injury

Proper surgical toilet with wound irrigation followed by careful debridement remains the mainstay of treatment of all types of soft tissue injuries.

#### **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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## **Dentoalveolar Injuries and Wiring Techniques**

Omkar Anand Shetye

#### **50.1 Defnition**

Dentoalveolar fracture is defned as a fracture in the bone surrounding the teeth without any extension to the basal bones of the maxilla or mandible [1, 2].

### **50.2 Incidence**

Dentoalveolar injuries commonly occur in the age group of 8–12 years. They generally involve teeth, soft tissues, and/or associated bone. Traumatic dental injuries account for a total of 92% of maxillofacial injuries of which 92% involves only the soft tissues and 8% involve the maxillofacial bones [2].

### **50.3 Introduction**

Trauma is the foremost etiological factor that leads to a loss of signifcant number of teeth annually. The recent advancements in the feld of preventive dentistry as well as the development of myriad evidence-based techniques to restore the lost form and function of teeth have made it possible for the dental surgeon to successfully facilitate the improvement in the quality of life of trauma-afficted patients. Time elapsed post-trauma plays a major factor in determining the outcome of the intervention. Apart from reestablishing the premorbid position of the traumatized tooth in its socket, the goal of the treatment is directed toward achieving the pre-traumatic occlusion and intra-arch contour [3].

O. A. Shetye (\*)

### **50.4 Diagnosis and Treatment Planning**

The foundation of diagnosis and management of traumatic dental injuries solely lies on the pillars of a detailed patient history and a clinical examination. **When, Where, and How** forms the "Trauma Triad" of history taking in traumatic dental injuries [4].

History of immediate local measures employed to reduce the severity of injury helps in eliciting information regarding the original condition of the injured area [6].

History of any systemic disorders that may interfere with treatment or post-operative healing including a history of tetanus vaccination has to be obtained before starting the treatment [7].

"Outside-in" examination (examining the facial structure in three concentric rings paying more attention to the innermost ring) helps in achieving the desired management protocol. Level of consciousness should be assessed prior to the clinical examination [6].

The potential for aspiration, airway compromise, and neurosensory defcit warrants the need for a thorough evaluation of all maxillofacial injuries before managing dental injuries [3].

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 1013

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_50

**Electronic Supplementary Material** The online version of this chapter (https://doi.org/10.1007/978-981-15-1346-6\_50) contains supplementary material, which is available to authorized users.

Department of Oral and Maxillofacial Surgery, Goa Dental College and Hospital, Bambolim, Goa, India

In a patient with missing tooth fragment or prosthesis, a chest radiograph and abdominal radiograph may be helpful in locating the missing structures and their management. Owing to its anatomic position, the right bronchus is often the site of foreign body dislodgement [3, 6].

#### **50.5 Clinical Examination**

Clinical examination of the patient has to be divided into the following subsets [8]:

#### **50.5.1 Extra-oral**

Asymmetry of the face following trauma could be due to injury to the facial skeleton or swelling. Areas of ecchymosis and hematoma may indicate fracture of the underlying osseous structure. Laceration, contusion, and abrasion of the overlying skin are common with dentoalveolar injuries (Figs. 50.1, 50.2, and 50.3). Mild antiseptic soap should be used to clean the extra-oral abrasions or a saline wash can be used while being careful to not inoculate injury site further with debris or foreign body [4, 8].

#### **50.5.2 Intra-oral**

Buccal mucosa lacerations should raise suspicion for a Stensen's duct injury. The lips, foor of the mouth, and tongue are areas which are at a risk of being penetrated or sites for secondary injuries [3].

#### **50.5.3 Jaws and Alveolar Bone**

Bimanual palpation of the maxillary and mandibular dentition and evaluation of occlusion should reveal areas of discrepancy or mobility. The direction of dislocation of the apex of primary tooth should be diagnosed since these teeth are in close approximation to the succedaneous teeth. Palpating from the vestibular approach makes this diagnosis easier. Sublingual ecchymosis/hematoma (Coleman's sign) at the foor of the

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.1** Mandibular anterior lingually displaced dentoalveolar fracture with degloving vestibular wound and ragged lip lacerations

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.2** Maxillary anterior palatally displaced and extruded dentoalveolar fracture with associated upper lip injury. Note incisal fractures of the upper lateral incisors (see also Fig. 50.8)

mouth is suggestive of underlying mandibular fractures. Step deformity, crepitation, malocclusion, and gingival lacerations raise suspicion for possible bone defects [7, 9].

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.3** Maxillary anterior teeth complete avulsion with associated upper lip injury

#### **50.5.4 Percussion and Pulp Testing**

Percussion test is performed with the end of the handle of an examination mirror. Pain to percussion of a tooth is indicative of damage to the periodontal ligament. Dullness to percussion in one or several adjacent teeth can be indicative of partially luxated teeth or en bloc fracture of tooth or alveolar bone. The percussion test should be started on a non-injured tooth to ensure a reliable response through visual analogue scale [6, 8].

To evaluate the tooth injury thoroughly, pulp vitality is a must. A positive response indicates that the pulp is alive, whereas a negative response indicates that the pulp is dead. Following injury, the tooth may be in a state of shock and may give a false response. Hence pulp testing should also be performed during the subsequent visits to acknowledge the change in response [5].

Electric vitality testing depends on a number of factors including the stage of eruption of tooth, the presence of a restoration or decay, and the ability to isolate the tooth and keep the area clear of blood and saliva [8].

Laser Doppler fowmetry (LDF) is a relatively new pulp testing apparatus. It employs a laser beam directed at the

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.4** Coronal CT image showing left maxillary high dentoalveolar fracture

coronal-labial aspect of the pulp which is scattered by pulp blood cells that in turn produce a Doppler frequency shift. The fraction of light scattered back is detected and processed to elicit a signal. The basic theory is that the pulp revascularization process can be monitored. Studies have shown that in cases in which electrometric tests were negative and LDF displayed vascular perfusion, the LDF accuracy of pulp vitality reached 100% [3].

All the teeth should be tested for abnormal mobility both horizontally and vertically. It should be remembered that primary teeth undergoing physiologic root resorption and therefore always exhibit a certain degree of mobility. The typical sign of an alveolar fracture is the movement of adjacent teeth when the mobility of a single tooth is tested [6].

#### **50.6 Radiographic Examination**

Radiographic techniques are available to evaluate dentoalveolar trauma.

Radiographic examination is essential to determine damage to underlying structures and should include intraoral periapical (IOPA), occlusal, panoramic radiographs (OPG), and cone-beam computed tomography (CBCT) imaging [3, 4].

If conventional CT imaging is done as part of the trauma series, fne axial and coronal cuts will also show the dentoalveolar injuries (Fig. 50.4)

IOPA radiograph provides vital information about root fracture and dislocation of teeth. At times it is diffcult to adequately evaluate a fracture on an IOPA radiograph, due to variations in tube-tooth-flm geometry. Post-treatment radiographs can confrm the proper repositioning of avulsed or luxated tooth into alveolar bone.

Occlusal radiographs provide a larger feld of view, and a steep occlusal exposure is of special value in the diagnosis of root fracture and lateral luxations with displacement of crown [8].

OPG is a useful screening tool and can demonstrate fractures of the mandible and maxilla as well as fractures of alveolar ridges and teeth.

Radiographic evaluation of foreign bodies within soft tissues of the lips and cheeks is done by taking radiographs with the flm placed labial to the alveolus. A reduced radiographic exposure time (approximately 1/3rd of the normal) is used.

The etiology of pediatric and adult dentoalveolar injuries were shown in Box 50.1 and Box 50.2 respectively. Box 50.3 and Box 50.4 represents the classifcation of alveolar bone fracture and classifcation of alveolar bone fracture based on location and displacement respectively.

#### **Box 50.1: Etiology of Pediatric Dentoalveolar Injuries Pediatric patients** [9]

#### **Box 50.2: Etiology of Adult Dentoalveolar Injuries Adult patients**

#### **Box 50.3: Classifcation of Alveolar Bone Fracture: Traumatic alveolar bone** [9]

Type I: Areas surrounding a single tooth

Type II: Entire dentoalveolar segment dislocation

### **Box 50.4 Alveolar fracture can be classifed by their specifc location and movement of displacement** [10]

#### **Box 50.5: Classifcation of Dental Injuries and Surrounding Structure**

#### **Classifcation based on level of involvement** [11]

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.5** (**a**–**c**) Clinical images showing tooth (a) intrusion, (b) extrusion, and (c) avulsion

#### **Box 50.6: Management of Intruded Tooth (Fig. 50.6) Diangelis et al.** [12, 13]

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.6** IOPA showing an intruded upper right canine

#### *Permanent Teeth*

	- Intrusion <3 mm—allow eruption
	- Intrusion between 3 and 7 mm—surgical or orthodontic repositioning
	- Intrusion >7 m m
		- (a) Surgical extrusion with fexible splint for 4–8 weeks
		- (b) RCT using Ca (OH)2 medicament 2–3 weeks after surgical extrusion
	- (a) Wait till the tooth erupts for 3 months
	- (b) Place an orthodontic extruding appliance

#### *Primary Teeth*

Treatment is debatable Immediate extraction of the involved tooth or More conservative approach

#### **50.6.1 Storage and Transportation Media**

If the tooth cannot be reimplanted within 5 min, it should be stored in a medium that will maintain its vitality and periodontal ligament fbers [14–16].

#### **Box 50.7: Principle of Avulsion**

#### **Box 50.8: Primary Management of Avulsion by the Patient**

What the patient can do:

What the patient should not do:

• No effort should be made to mechanically cleanse the root of the tooth because this would damage the remaining periodontal ligament.

Transportation media for avulsed teeth include

Commercial products are designed especially for storing avulsed teeth. It has shelf life of 2 years without refrigeration (Box 50.9).

3. Milk: is a readily available medium. It is the medium of choice in the absence of hanks balanced salt solution or viaspan. Milk will only prevent further cellular demise and is used specifcally when the teeth has been outside the oral cavity for less than 20 min.

#### **Box 50.9: HBSS Contents**

Contents of Hanks balanced salt solution [19]

*Morus rubra* (red mulberry), egg white, coconut water, rehydrating solution like Gatorade and ricetral, lens solution, probiotic solutions, saliva offcinalis, honey milk, and ascorbic acid have been used as a transportation medium for avulsed tooth.

#### **50.7 Treatment at the Clinic**

Traumatically avulsed teeth when out of the mouth for a short period should be reimplanted as soon as possible.

#### **Box 50.10: Reagent for Root Surface Therapy**

Agents used for root surface treatment to prevent resorption

After normal reattachment, survival is prolonged. Avulsed teeth which remain out of the mouth for more than 2–3 h generally resorb rapidly and should not be reimplanted indiscriminately.

The outcome of replantation depends on the stage of root development and extra-oral time. If the avulsed tooth has a closed apex and extra-oral time is less than 60 min (early replantation), the reimplanted tooth will have the best prognosis. The ideal time to begin root canal treatment is within 10–14 days post-replantation and before splint removal.

There is a statistically signifcant association between extirpation within 14 days and an increased likelihood of successful periodontal healing and prevention of external infammatory root resorption.

It is generally agreed that Ca (OH)2 has a benefcial effect in the outcome because of its antibacterial properties, ability to dissolve necrotic tissue, and its ability to prevent or control infammatory resorption. The anti-infammatory and antibacterial action may decrease root resorption by directly inhibiting resorptive cells (Box 50.10).

#### **50.7.1 Delayed Replantation (more than 60 min)**

Delayed replantation of avulsed tooth with closed apex has a poor long-term prognosis. The periodontal ligament gets necrotic and healing is delayed. The goal of delayed replantation is to promote alveolar bone growth so as to encapsulate the reimplanted tooth. The eventual outcome is ankylosis.

In children below age of 15 years, if ankylosis occurs and when the infra position of the tooth crown is more than 1 mm, decoronation is recommended to preserve the contour of the alveolar bone.

Root canal treatment (RCT) can be carried out on a tooth prior to reimplantation or it can be carried out within 14 days of reimplantation. The tooth is immersed in 2% sodium fuoride solution for a minimum of 5 min up to 20 min.

Avulsed teeth having open apices and extra-oral time less than 60 min are also reimplanted and stabilized for 7–10 days and up to 2 weeks. The goal of reimplanting developing (immature) teeth in children is to allow for possible revascularization of the tooth pulp.

If there is evidence of the pulpal infection or infammatory response, the pulp should be removed and Ca (OH)2 placed immediately, aiming to stimulate apexifcation and halt the infammatory process.

It is believed that delayed replantation of avulsed teeth with open apices have a poor long-term prognosis. The periodontal ligament gets necrotic and is not expected to heal. Osseous replacement, resorption, or ankylosis will occur. Therefore some authors have concluded that such teeth should not be reimplanted.

The recent guidelines recommend replantation to maintain alveolar ridge contour as ankylosed roots get transformed to bone during the remodeling process. RCT can be performed on the tooth prior to replantation through an open apex (Fig. 50.7a–c).

#### **50.7.2 Stabilization**

**b**

Stabilization of an avulsed tooth can be achieved using a variety of materials like wires, arch bar wired to the teeth,

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.7** (**a**–**c**) Shows a case of avulsed upper right central incisor in a 24-year-old man, which presented after few hours of avulsion. The tooth was transported in milk by the relatives. A RCT was carried out and the tooth reimplanted and stabilized with wire and composite splint (**a**, IOPA showing avulsed incisor; **b**, IOPA with tooth reimplanted; **c**, shows the clinical image after splinting)

**a**

**c**

orthodontic band and brackets attached by acid etch technique, combined with orthodontic band and acrylic appliance, or periodontal pack.

They are generally maintained for 7–10 days after replantation to allow gingival reattachment.

Studies by Andreason [20] (1985) have shown that prolonged splinting may be inadvisable because it enhances ankylosis.

The socket should be left undisturbed before replantation. If the alveolar bone has collapsed, a blunt instrument should be inserted carefully into the socket in an attempt to reposition the wall. It should be lightly aspirated if a blood clot is present.

In general, stabilization for reimplanted teeth is required for 7–14 days. The periodontal ligament fbers should have healed suffciently after the frst week to remove the splint. However, the patient should be advised not to bite directly on the reimplanted tooth for 3–4 weeks after injury.

#### **50.7.3 Technique**

#### **<IP_ADDRESS> Wire Acid Etch Composite Splint**

A wire of moderate stiffness (round 0.030 in. stainless steel) is adapted to the facial surface at least one or more stable teeth on either side of the reimplanted teeth.

The physiologic movement imparted to the reimplanted tooth during function is increased when fewer teeth are included in stabilization of the avulsed tooth.

The facial surface of the avulsed and adjacent teeth is acid etched, and wire is cemented to them with composite.

The wire is generally curved along the middle third of the labial surface of the teeth. 90° terminal bends toward the gingiva are made at the labiodistal angles of the most posterior teeth to be splinted in order to avoid sharp edges and stability. The terminal ends should be about **2 mm** long to reduce the possibility of lateral displacement of the wire [21, 22].

#### **Splinting periods for traumatic dental injuries** [6]

#### **50.7.4 Complications**

	- (a) Surface replacement
	- (b) Replacement resorption (ankylosis)
	- (c) Soft tissue replacement [23]

#### **50.8 Alveolar Process Fracture**

Fracture of the alveolar process usually involves the teeth.

Open reduction/ raise the fap if reduction not possible (Fig. 50.9 a, b)

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.8** Shows the case in Fig. 50.2, which has undergone closed reduction and fxation by arch bar. Full intrusion and reduction was not achieved. The occlusal discrepancy was planned to be corrected later by RCT and necessary prosthetic work

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.9** (**a**, **b**) Shows a case of high alveolar process fracture segment in the maxillary right side with associated split between central incisors. Under GA, the extruded displaced alveolar segment was repositioned after placement of split arch bars and bridle wiring between the central incisors. The segment was fxed with mini plate and screws, taking care not to injure the tooth roots. Due to root anatomy, only a single plate was fxed after reduction. Post-operative IMF was given for 2 weeks, for additional stability and to help the healing process

### **50.9 Management of Dentoalveolar Fracture**

The goals of treatment should be:

#### **50.9.1 Treatment Options**

Model surgery on the plaster models is performed to recreate the normal anatomic relationship of the fractured segment and allow fabrication of accurate splint [9].

#### **50.9.2 Specifc Treatment Options**

Class I fractures that involve a non-displaced, edentulous alveolar segment often do not require treatment other than a soft diet and observation. If there is concern about the stability of the fracture during the healing process, stabilization may be used.

Class II fractures that involve a displaced dentulous segment and need reduction may require a great deal of force to realign the fractured segment. Posterior fragments are always displaced to the lingual area. Large forceps may be helpful to apply a force suitable to reduce the bony fragment. Reduced fragments are held in place by MMF or splints.

Class III fractures of a moderately or severely displaced dentulous segment may be too diffcult to reduce adequately. There may be scant room into which the irregular, displaced segment needs to be replaced. It may be necessary to burr or rasp down the displaced segment or the opening in the remaining bone to successfully reduce the fracture. This is usually accomplished by use of a power drill with a suitable size bur or a fne rhinoplasty rasp. The amount of tissue that is removed should be limited so that the suffcient bone to bone contact remains for bony union as the fracture heals. Maintenance of class III fractures in a reduced fashion may be accomplished with arch bars, MMF, and/or variety of splints.

Class IV fractures that extend into one or more non alveolar fracture lines are usually less challenging than class III fractures because (1) the bone segments are larger, (2) the treatment of the associated fractures gives excellent exposure, and (3) usually no barrier exists to reduction. Plates, screws, arch bars, MMF, and/or variety of splints may be used [7].

#### **50.9.3 Wiring Techniques**

In MMF, wires are passed interdentally between teeth in both the jaws followed by tightening of these wires together in a cross arch fashion which serves to stabilize the fracture segments.

Over the period of last century, MMF techniques have evolved dramatically, and more recently, many more easier and effective methods have been introduced like MMF screws, eyelet wiring, and Erich arch bars to name a few. Although it is a quick and effcient way of securing MMF, yet, this technique is criticized for extended periods the patient needs to be closed mouth, diffculty in maintaining oral hygiene, lack or defcient nutritional support via oral route and inability to use this treatment modality in medically compromised patients like epileptics or in immediate post-operative period due to increased risk of aspiration.

#### **50.9.4 Armamentarium and Principles**  (Fig. 50.10)

A soft stainless steel wire of 0.35–0.5 mm diameter is utilized and pre-stretched to 10% of its original length to prevent loosening of wire once tightened. Overstretching beyond this point should be avoided as this will make the wire brittle and susceptible to breakage.

#### **50.9.5 Principles**

Basic principles to be followed are [25]:

#### **50.9.6 Technique**

#### **<IP_ADDRESS> Bridle Wire** [26, 27]

First advocated by Hippocrates, bridle wire remains one of the oldest yet a conventional method of treating mandibular fractures. This technique represents a temporary way of stabilizing the fractured segments, preventing them from faying apart.

Advantages include stabilization of the two fractured segments preventing further damage to the adjacent soft tissues, maintenance of the airway patency (especially advan-

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.10** Armamentarium for wiring

tageous for the fractures of the anterior mandible), decrease pain, and reducing damage to the neurovascular bundle from immobilizing the fractured fragments, thereby preventing gross movements and also decreasing muscle cramping.

#### **Technique**

Following administration of local anesthesia , a 24–26 gauge wire is passed around the neck of the teeth adjacent to the fracture site on either side (Fig. 50.11a). With both ends being secured in the wire holder (Fig. 50.11b), the fractured segments are manually reduced anatomically, and the wire is tightened in a clockwise fashion till further reduction is achieved (Fig. 50.11c), and the fracture is stabilized

## **<IP_ADDRESS> Gilmer's Direct Interdental Wiring**

[26, 27]

This technique represents an easy and fastest method of immobilization.

#### **Technique**

A 15 cm pre-stretched wire is passed through the interdental embrasure of the tooth on one side from buccal to lingual. This wire will pass around the tooth and emerge out buccally through the interdental embrasure from the other side. Both ends are held together and twisted to achieve a 3 cm tail (Fig. 50.12a–c). Multiple teeth (at least 5–6) in either jaw are utilized. Following manual fracture reduction and placement of teeth with premorbid occlusion, the tails from opposite arch are twisted together in a cross arch or zigzag fashion to achieve immobilization (Fig. 50.12d). The cut ends of the tail are secured into the interdental spaces. Once all the wires/tails are twisted, complete immobilization is achieved.

The only drawback of this technique is that, in cases of broken /loose wire, all the cross arch wires will have to be removed and redone post placement of twisted wire.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.11** Shows sequential steps bridel wiring. (**a**) Passing of the wire through the tooth embrasure. (**b**) Formation of the wire loop assuming the fracture line is between the two premolars. (**c**) Twisting of both the ends to stabilize the fracture

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.12** (**a**–**d**) Shows technique of direct Gilmer wiring. Formation of the loop around the tooth in the lower and upper arch followed by twisting both the wires together in order to achieve MMF

#### **<IP_ADDRESS> Interdental Eyelet Wiring (Ivy Loop Method)** [26, 27] (Video 50.1)

Yet another easy and quick method of securing MMF was advocated and popularized by Dr. Robert H.Ivy, Philadelphia, USA.

#### **Technique**

A pre-stretched 26 gauge/0.35 mm diameter wire was made into an Ivy loop utilizing the middle segment of the wire by twisting it around a metallic rod of 3 mm diameter. 3–4 turns are given to achieve adequate stability to the loop. Both the ends of the wire are then cut in an oblique fashion (Fig. 50.13a).

Both the ends are passed through the interdental space to emerge lingually/palatally so that the loop lies buccally (Fig. 50.13b). Following this, one end of the wire is passed from distal interdental space of the same tooth to emerge buccally. This same wire is passed through the loop and secured to the other end of the wire which is passed mesially from the lingual/palatal side to the buccal side of the adjacent tooth side (Fig. 50.13c,d) . Both the ends are tightened (Fig. 50.13e), and the tail end cut short and secured into the dental space mesially to prevent damage to the adjacent soft tissues.

Stability of the MMF is based on the adequate number of Ivy loops placed in both the arches and secured.

In the maxillary arch, loops can be placed between two molars, two premolars, or between lateral incisor and canine or two central incisors. In the mandibular arch, loops are best placed between two molars, two premolars, or between lateral incisor and canine.

#### **Modifcations**

1. In 1975, Hallam modifed the Ivy loop by addition of another loop proximal to the frst for the purpose of ligature/tie wire (Fig. 50.14)

Although an interesting modifcation yet the disadvantage observed was that due to increase in length and in patients with short vertical dimension, both the proximal loops would meet one another making the placement of MMF extremely diffcult.

2. **Clove hitch**

This technique helps in placement of an Ivy loop in cases of missing teeth or a single isolated tooth. It is the easiest way to secure MMF where placement of an arch bar or any other technique of securing MMF is diffcult due to lack of supporting teeth.

#### **Technique of Clove Hitch**

The one end of the wire that has an Ivy loop forms a loop around the lone-standing tooth (Fig. 50.15a) . Continue the wire around the tooth forming another loop for the second time (Fig. 50.15b) . The end of the wire is under the frst loop (Fig. 50.15c), and both the ends of the wire are pulled together and tightened (Fig. 50.15d).

#### **<IP_ADDRESS> Continuous or Multiple Loop Wiring**  [26, 27]

It was frst described by Col. Stout in 1943. It represents an easy and simple technique which requires minimal instrumentation. This technique utilizes multiple loops on the buccal surface of the tooth which can be used for both MMF using wire as well as elastic traction for the purpose of fracture reduction. One major advantage of this technique is the use of differential traction force that can be achieved and applied for fracture reduction before securing it with wires for MMF.

#### **Technique**

A 30 cm-long pre-stretched wire is placed on the buccal side of the teeth with the anterior end placed as anteriorly as possible while the posterior end extending up to the last tooth to be used. The wire is passed through the interdental space of the posterior most teeth and emerged through its mesial side. The wire is then passed over the buccal wire and passed back into the same interdental space. A 3 mm diameter rod can be used parallel to the buccal wire for adequate loop diameter as well as uniformity of the loop (Fig. 50.16a). Once the wire is passed back through the same interdental space, it then emerges out from the mesial interdental space of adjacent tooth (Fig. 50.16b). This continues till the anterior most teeth where both the ends of the wire are twisted together, cut, and placed into the interdental space (Fig. 50.16c,d). Each loop is then twisted, and loops are made of uniform diameter. In cases of securing MMF, the loops are turned toward the occlusal surfaces of the teeth, but in cases of elastic traction, they are turned in the opposite direction toward the gingiva [27].

#### **Modifcation**

This technique needs modifcation when some teeth are missing. Herein, once the loop at the mesial end of the tooth adjacent to the missing tooth is formed, both of the free ends of the wires are held together and twisted till the distal end of the next tooth. Once the desired length is achieved, the loop is again formed at the distal end, and the looping continues till the anterior most teeth.

#### **<IP_ADDRESS> Risdon's Wiring** [26, 27]

#### **Indications**

It is an alternative to an arch bar for a fractured mandible that needs fxation.

#### **Technique**

A 25 cm-long wire is passed through the posterior most tooth in the quadrant to emerge bucally, followed by twist-

**Fig. 50.13** Shows steps in Ivy loop technique. (**a**) Photograph of an Ivy loop. (**b**) Both the ends are held together an passed through the tooth embrasure of the premolar and molar. (**c**) One end passed is passed through the mesial of premolar and other through the distal of

molar to emerge buccally. (**d**) Distal end is passed through the loop on the buccal side to emerge mesially. (**e**) Both the ends of the wire are held together and twisted

©Association of Oral and Maxillofacial Surgeons of India

```
Fig. 50.13 (continued)
```
©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.14** Shows a modifcation of Ivy loop

ing the wire up to its full length till the midline (Fig. 50.17a). Another wire is passed from the opposite quadrant of the same arch and twisted in a similar manner. Both the ends of this twisted wire are tightened at the midline after reducing the fracture segments (Fig. 50.17b,c). Once anatomic reduction is achieved, additional wires are used to stabilize this long wires by passing around the embrasures of the teeth and looping around the wire segment (Fig. 50.17d) [26, 27].

#### **<IP_ADDRESS> Obwegeser Wiring** [26, 27] **Technique**

This technique utilizes a 30 cm-long wire that is bent into a continuous "W" arcade form as depicted in Fig. 50.18a. The elevated portion of the arcade acts to form the loop, whereas the depressed portion adapts to the contour of the teeth palatally or lingually. The distal end of the wire arcade is kept long enough so that it will follow the buccal contour of the arch, when it is passed through the interdental space of the most posterior tooth from lingual/palatal to buccal side. The elevated ends of the

**Fig. 50.15** Showing clove hitch technique. (**a**–**c**) Single loop is passed around the lone-standing tooth followed by second loop under the frst one, pulling both the ends together. (**d**) Showing clove hitch wiring technique

arcade have a ligature wire attached to it (Fig. 50.18b), which only suffices the arcade to be pulled through to the interdental space to emerge buccally (Fig. 50.18c,d). The long wire is then passed through this loop (Fig. 50.18e), and a modified hemostat is used to twist this wire to form uniform loops. At the mesial end, both the ends of the wire are held together and twisted (Fig. 50.18f). The loops can be used for both elastic traction and wires for securing MMF.

The disadvantage of this technique is that it is very cumbersome and adequate expertise is needed to carry out this technique.

**Fig. 50.16** (**a**, **b**) Showing continuous or multiple loop wiring technique, a rod is held parallel to the buccal surface of the teeth, and the wire is passed through the distal most tooth embrasure to emerge buccally and looping around the rod. (**c**, **d**) Continuous loops till the midline are made followed by pulling the buccal rod out to achieve loops

#### 50 Dentoalveolar Injuries and Wiring Techniques

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.17** (**a**, **b**) Showing steps in fabrication of Risdon wiring. Distal most tooth is used to loop the wire and twist it. (17c) Showing twisted wire in the midline. (**d**, **e**) Showing wires passed through teeth embrasure to loop around the main wire. (**f**) Alternate method of securing the long wire

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.18** (**a**, **b**) Showing fabricated W arcade used in Obwegeser technique. (**c**) Showing ligature wire pulled from the palatal/lingual side to buccal side. (**d**–**f**) Showing wire from the distal most end passing though the loops to be twisted at the most medial end of the arcade

#### **<IP_ADDRESS> Arch Bar** [26, 27] (Video 50.2)

Commercially available arch bars are usually customized or prefabricated. In most clinical scenarios, prefabricated arch bars like Erich's, Jelenko, Winter's, or Schuchardt's suffce the need for placement.

#### **Indications**

#### **Technique**

Ideal placement is as close to the interdental spaces, which are then secured with 26 gauge wire. This close placement helps to reduce the arch bar to tooth contact and allows for better adaptability of the arch bar to the arch contour, thereby reducing loosening of arch bar.

In most cases, arch bars are placed from distal of frst molar, in one quadrant to the other, maintaining a minimum of two teeth on either side of the fracture line in a dentate patient.

The wire is passed from one interdental space and moved around the tooth to emerge buccally from the other side (Fig. 50.19a). Placement of arch bar by securing it with wire begins (Fig. 50.19b) usually at the midline and proceeds posteriorly or from one end (molar) to another (Fig. 50.19c,d) in order to avoid excess in the center and to achieve uniformity throughout the length of the arch bar. The wires are usually twisted in between the cleats and placed into the interdental space to avoid damage to surrounding soft tissues.

The cleats of the arch bar always face gingivally. MMF is usually secured using 24 gauze wires in box pattern.

Figure 50.19e is showing a model with upper and lower arch bar placement secured with wires, while Fig. 50.19f is showing a clinical photograph of arch bar placement.

#### **Advantages**

#### **Disadvantages**

• One of the major drawbacks is the lack of vertical stop in the anterior region when an arch bar is used. In the posterior region, the opposing teeth act as a vertical stop for occluding teeth which isn't the case with anterior region as the anterior upper teeth may slide over the lower when elastics are stretched between the maxillary and mandibular teeth resulting in extrusion of anterior teeth. This problem can be circumvented, by drilling a hole using a bur in the gingival area apical to the mucogingival junction through the buccal and lingual cortices.

An additional 24 gauze wire is passed from the buccal side of this hole to emerge lingually. The lingual end of the wire is then passed through the interdental space of the tooth to emerge buccally. Both the ends of the wire are then twisted to prevent extrusion.

In the anterior maxilla, anterior nasal spine can be used for additional suspension of the arch bar to prevent downward pull exerted by the elastics.

#### **Complications**

Post reduction of the dentoalveolar fracture, the incisal edges of the fractured teeth bearing segment will remain above the normal occlusal plane. This discrepancy can be corrected by application of apical pressure to this segment through MMF, circummandibular wiring, suspension from ANS, lateral piriform, buttress, or using the eye of the maxillomandibular fxation screw.

#### **50.10 Maxillomandibular Fixation (MMF) Screws** [28] (Video 50.3)

#### **50.10.1 Introduction**

A self-drilling or tapping maxillomandibular fxation screws by Arthur et al. [29] in 1989 reduced the intra and postoperative problem associated with the arch bars.

#### **50.10.2 First Generation**

Screws were modifed monocortical self-tapping screws that were kept at 4–5 mm above the mucosa for subsequent wire

**Fig. 50.19** (**a**–**d**) Showing technique of arch bar placement. The wire is passed through the embrasure or emerge buccally. The wire on the mesial side of the tooth is passed above the arch bar, where as the distal end wire

is passed below the arch bar to secure it by twisting. (**e**) Showing a model with upper and lower arch bar placement secured with wires. (**f**) representing a clinical photograph of arch bar placement

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.19** (continued)

splinting. Surgical preparation of the site needed prior to insertion. They were usually wider in diameter with grooves/ futes.

#### **50.10.3 Second Generation**

Screws were self-drilling or self-tapping screws which were spool shaped. The central part of the screw head is perforated with one of two channels perpendicular to its axis aiding in the passage of ligature wires. The top of the screw heads is smoothly fnished at the contact zone with overlying mucosa.

Clinician should consider fracture location, dentition, surgical exposure, and the quantity of bone for placement of these IMF screws.

Ideal radiographic images obtained are orthopantomogram and CT axial scan to analyze and plan placement of these screws.

Sites include anterior vestibule and anterolateral (canine and premolar regions) as they provide suffcient bone depth, clearance from adjacent tooth, and easy accessibility. Screws should be placed above the root apices as subapical placement leads to mucosal overgrowth (Fig. 50.20a–d).

Ideally one screw should be placed on either side of the fracture line. However, in severely displaced cases, it is advisable to use multiple screws on either side to achieve vectors in different directions.

#### **50.10.4 Advantages**

#### **50.10.5 Disadvantages**

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 50.20** (**a**–**d**) Showing clinical steps in placement of MMF screw. Technique for placement of MMF screws. Marking is done between the root apices followed by drilling and placement of MMF screw, one in each quadrant. The wire is passed through the eye of the opposing arch and secured to achieve intermaxillary fxation

#### **50.11 Conclusion**

Dentoalveolar fracture mostly involves teeth, soft tissues, and associated bones. With the recent advancements in the feld of dentistry, the oral and maxillofacial surgeon can restore the lost form and function of teeth to facilitate the improvement in quality of life in traumaafficted patients.

**Acknowledgments** For Figs. 50.1, 50.2, 50.3, 50.4, 50.6, 50.7, 50.8 and 50.9 to Suvy Manuel.

#### **References**

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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.

## **Principles of Internal Fixation in Maxillofacial Surgery**

Abhilasha Yadav

### **51.1 Introduction**

Road traffc accidents (RTA) are one of the primary etiologies of craniomaxillofacial fractures. Open reduction and internal fxation (ORIF) is the most important treatment modality to restore the compromised form and function. Adequate reduction and fxation with miniplate osteosynthesis is the essential component of management.

### **51.1.1 Association of Osteosynthesis (AO Principles)**

The following are guidelines for internal fxation based on the four basic principles formulated by AO in 1958.

### **51.2 History**

According to him, there was a need for compression between the fragments of fractures. He used a plate called coaptens to achieve this goal, which increased stability and suppressed interfragmentary motion. The mode of healing initiated by this is called soudure autogene (autogenous welding) now known as primary bone healing.

6. In 1967, mandibular compression screw (MCS) was used in oral and maxillofacial surgery (OMFS) in edentulous fractured mandible while performing frst compression osteosynthesis. Self-tightening/automatic MCS plate was developed by Luhr in 1968. Later, dynamic plates were advocated for surgery of long bones with subsequent application in mandibular fractures.

**51**

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 1039 K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_51

A. Yadav (\*)

Department of Oral & Maxillofacial Surgery, Awadh Dental College & Hospital, Jamshedpur, Jharkhand, India

1881 Glimer On either sides of the fracture, two heavy rods 1886 Hansmann Retrievable bone plates 1945 Christiansen In mandibular fracture-tantalum plates 1956 Bagby First compression plate 1960 Luhr and Mittlmeir Improved mandibular compression plates 1969 AO/ASIF Dynamic compression plates (DCP) 1970s Brons and Boeriing Lag screws 1973 Schmoker and Spiessel (EDCP) eccentric dynamic compression plates 1973 Michelete Miniplates 1975 Champy Monocortical screws principal for fxation 1977 Luhr Compression plates for the frst time in management of fracture mandible 1977 Spiessel For mandible fracture advocated AO/ASIF principle 1989 Bos Resorbable plates and screws 1994 Dynamic compression plate with locking compression plate 2011 Development of locking compression plate with combination holes

**Table 51.1** History of development of fracture management modalities

#### **51.2.1 Evolution of Fixation Methods**

History of development of fracture management modalities [2–4] (Table 51.1)

#### **51.3 Concept of Bone Healing**

#### **51.3.1 Secondary Bone Healing** (Fig. 51.1)

#### **<IP_ADDRESS> Stage I: Infammation Induction**

Immediately after fracture, hematoma formation occurs; hematoma plays a vital role in the angiogenesis of the healing fracture. Subsequently, infammatory cells, stem cells, and fbroblasts initiate infammatory response and enhance angiogenesis. Cytokines which helps in bone repair are released in this phase and hematoma is removed. Within 3 days, thin layer of fbrous tissue covers the periosteal surface of fractured bone. The cortical bone adjacent to fracture site becomes necrotic which later gets remolded by multinucleated osteoclast.

#### **<IP_ADDRESS> Stage II: Fibrocartilaginous (Soft) Callus Formation**

Dense fbrous tissue, cartilage, and fbrocartilage formation occurs due to organization of subperiosteal hematoma; soft callus is composed of internal (endosteum of marrow cavity and lining of Haversian canal) and external components (periosteum and organizing hematoma) and continued proliferation of osteoblasts; fbrocartilaginous tissue begin to calcify as the periosteal and endosteal circulation develops. The conversion of chondrocytes to osteocytes occur and the entire callus is converted to immature woven bone.

#### **<IP_ADDRESS> Stage III: Hard Callus Formation**

After 3–4 weeks of fracture, the hard callus begins to form and osseous union of the fractured cortical bone starts.

#### **<IP_ADDRESS> Stage IV: Remodeling**

The trabeculae orient themselves in the direction of functional pressures after bone formation.

#### **51.3.2 Primary Bone Healing (Contact and Gap Healing)**

Healing without callus formation is called as primary bone healing. When there is direct apposition of cortical bone surfaces, contact healing occurs. Osteoclasts widen the Haversian canals on either side of the fracture and move toward each other. The cortical bridging occurs in 8 weeks and is usually completed in 16 weeks. In gap healing also primary bone healing occurs; gap as wide as 100 μm can be flled with mature lamellar bone (Fig 51.2).

#### **51.4 Biomechanics of Facial Skeleton** [5]

#### **51.4.1 Mandible Fractures**

The mandible is a class III lever with:

Simple beam mechanics described the traditional biomechanical properties of mandible, which represents compression at inferior border and tensile forces on the superior border with an applied anterior load (Fig. 51.3). The "neutral axis" is the line of zero stress where the tensile forces become compressive, and it is approximately at the level of the inferior alveolar canal. Compression and tension will be produced in symphysis region due to torsional forces.

The muscles inserting on the mandible and forces exerted by these muscles during function, determine the tension and compression zone in cases of fracture mandible.

The direction of the muscular forces acting on the mandible by temporalis, lateral pterygoid, pterygomasseteric sling, and suprahyoid musculature is shown by arrows in Fig. 51.4. For successful treatment of facial fractures in the form of rigid fxation, the understanding of biomechanics of facial injury is very important.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.2** Contact and gap healing (arrow denotes contact healing)

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.3** Tensile and compressive force mechanism

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.4** Direction of muscular forces

#### **51.4.2 Midface Fractures**

Midface generally does not show muscle forces acting on them except for zygomatic bone, on which masseter exerts the primary force which can create notable bony displacement causing inferior and medial displacement especially in the presence of temporalis fascia disruption (Table 51.2).

**Table 51.2** The four articulations of zygoma with their functions in management of fracture

#### **51.5 Functions of Plates**

#### **51.5.1 Compression**

Compressing together the main fragments of a single plane fracture can result in absolute stability, i.e., the complete abolition of interfragmentary movement. Interfragmentary compression in single plane, as in diaphyseal fractures, can be achieved by exploiting the eccentric loading capabilities of the dynamic compression family of plates.

The screw is inserted in a neutral mode, and plate was fxed to the right-hand fragment. In an eccentric (load) mode, a screw is then inserted into the left-hand fragment. As the load screw is fully inserted, it engages and slides down the sloping surface of the plate hole, and the screw and bone move toward the fracture, compressing it.

If the plate that exerts axial compression is exactly contoured to the anatomically reduced fracture surface, there will be some gapping of the opposite cortex when the plate is tensioned by tightening the load screw. This is due to the compression being maximal immediately beneath the plate and not evenly distributed over the whole area of the fracture plane. The solution to this problem is to "overbend" the plate so that its center stands off 1–2 mm from the anatomically reduced fracture surface. Slight gaping of the cortex will occur directly underneath the plate when the neutral side plate is applied to the bone. The tightening of load screw causes tension in the plate and compresses the fracture evenly across the full diameter of the bone.

#### **51.5.2 Neutralization**

A primary lag screw fxation, exerting interfragmentary compression, can be vulnerable to disruption by physiological bending and/or rotational forces. Such a primary fxation is usually protected by the use of a plate, spanning from one main fragment to the other—this "neutralizes" the disruptive forces. All such forces are then transmitted via the plate and bypass the primary lag screw fxation.

#### **51.5.3 Tension Band**

If a body with a fracture is loaded at each end, over a bending point (fulcrum), tension (distraction) forces are generated, maximal on the side opposite the fulcrum, and angulation occurs. However, if an inelastic band, such as a plate, is anchored to the tension side of the body, same load will generate compression across the fracture interface. This is known as the tension band principle.

#### **51.6 Fixation Methods and Devices** [6] (Table 51.3)

Commonly used devices used for fxation are wires, staples, pins, and screws [6].

#### **51.6.1 Material**

Most commonly used materials are titanium (Ti-6Al-4V) and stainless steel (316L). Stainless steel has been used because of its greater biocompatibility and corrosion resistance. Since 1980 titanium was used in maxillofacial surgery.

#### **51.6.2 Rigid Fixation**

The internal fxation is defned as the placement of wires, plates, screws, rods, pins, and other hardware to stabilize the fracture fragments.

#### **<IP_ADDRESS> Rigid Internal Fixation (RIF)**

RIF is defned as "bone fxation of any form in which biomechanical forces are either countered or used to stabilize the fragments of fracture and permits loading of bone to permit active action" [7].

#### **<IP_ADDRESS> Examples of RIF**

Examples of RIF are the use of bone plates and screws, two lag screws, and use of reconstruction plate with three screws on each side of the fracture fragment. Use of long compression plate is also included in the rigid internal fxation examples.

*Healing*: In the rigid internal fxation, no callus formation is formed during bone healing. The fracture bones heal by a process of Haversian remodeling. This primary or direct bone union requires immaculate immobilization between osseous fragments, i.e., minimum gap between the rigid fxation. Examples of rigid fxation for fracture mandible are shown in Fig. 51.5a,b.

#### **51.6.3 Nonrigid Internal Fixation**

It is a kind of fxation that is not strong enough to prevent interfragmentary motion completely. Thus interfragmentary motion is the differentiating factor between rigid and nonrigid fxation. Any mobility between fragments stabilized through internal fxation on active usage of skeletal structure signifes nonrigid fxation.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.5** (**a**, **b**) Techniques of rigid fxation for mandibular fracture. (**a**) Fixation with single miniplate and tension band; (**b**) fxation with two miniplates

Transosseous wiring across a fractured mandible is a good example of nonrigid fxation. The wire is unable to neutralize torsion/or shear forces and requires other fxation methods like MMF (maxillomandibular fxation).

*Healing*: The bone healing that occurs under the condition of mild mobility between fragments is called as secondary bone healing. There is deposition of periosteal callus in such circumstances, followed by resorption of fragment peripheries and tissue differentiation through various stages from fbrous to osseous healing.

#### **51.6.4 Semirigid Fixation**

Semirigid fxation is based on load-sharing osteosynthesis. Semirigid fxations include the use of:

#### **51.6.5 Load-Bearing Versus Load-Sharing Fixation** (Table 51.4)

#### **51.7 Classifcation of Plating System** [8]

	- (I) Mandibular compression screw system
	- (II) Mini system
	- (III) Micro system
	- (IV) Mandibular reconstruction system
	- (II) Reconstruction plates

#### **51.7.1 Locking Plate-Screw Systems**

In the late 1950s, AO group put forth the tenets which are followed in traditional plates and screws. This included exposure of fracture with anatomic reduction and internal fxation of fracture fragments with the desired result of anatomic bone union [9]. The stability of these plates is achieved by locking the plates by the screws.

Conventional screw – bone plates system requires plate to adapt precisely. In the absence of this contact, the tightening of screw will draw the segments of the bone toward the plate which results in change of the occlusion and bony segments.

On the other hand, the locking plate-screw system does not require the intimate contact of plate to the underlying bone in all the areas. The screw tightening locks the plate and thus stabilizes the bone segments without compressing the bone to the plate. Alteration in reduction is impossible after screw insertion.

According to Herford and Ellis [10], the locking plate and screw system are simple to use. Like compression plate it does not require plate to be compressed to the bone.

Klotch et al. [11] also concluded that the locking plates require less time due to less bending and faster application with good results.

Locking plate and screw come in two designs, i.e.:

The threaded locking plate - screw system features corresponding machined threads incorporated in both the screw and plate. Whereas, the tapered locking screw - plate system has a screw head which is tapered in shape with machined threads, with the plate either having no machined threads or a single machined thread incorporated into its design. This facilitates a more fexible locking mechanism which allows for screw angulation of upto 10 degrees, in comparison to the threaded locking system which needs absolute perpendicular screw placement [12].

#### **51.7.2 Reconstruction Plates**

The rigid plates with 2.7 mm bicortical screws were introduced by AO/ASIF in 1972 [13].

The main advantage attributed to the non-locking reconstruction plate, is its "load bearing" principle. Scolozzi and Richter [14], used the 2.4 mm AO Titanium plates for the management of mandible fractures, with good outcomes and very less complications.

They are available in different shapes for specifc areas like angle reconstruction plate (Fig. 51.6), condylar reconstruction plate (Fig. 51.7), and straight reconstruction plate with different lengths.

#### **Indications**

The advantages of rigid fxation with grafting include immediate jaw function and excellent stabilization of graft. The main disadvantage at the graft site is disuse osteoporosis or "stress shielding." This phenomenon occurs when rigid plates absorb the mandibles functional stress. To protect the long bones from stress, the plate's modulus of elasticity will have to exceed in comparison with the bone to which it is attached. Osteoporosis and reduction in bone strength are the result of protection from stress or shielding in long bones [15].

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.6** Angle reconstruction plate

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.7** Condylar reconstruction plate

#### **51.7.3 Lag Screw Fixation**

In oral and maxillofacial surgery, Brons and Boeriing introduced lag screw fxation for the frst time in 1970. According to them two lag screws prevent rotational movements of the fracture fragments in oblique mandibular fractures [16].

#### **<IP_ADDRESS> The Principle of Lag Screw**

The lag screw principle is used whenever two wide contact surfaces of the bone should be pressed together (for mandibular oblique sagittal fractures or onlay graft fxation).

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.8** Orthopantomogram showing fxation with lag screws

Through the outer cortex or onlay graft, the drilling of the hole was carried out of the identical diameter to that of screw so that the screw slips through the outer cortex. The lag screw drill, which is of the same diameter as the screw, will simultaneously create a conical countersink to provide an optimal ftting of the screw head. The inner cortex is then perforated with the normal surgical drill, and the screw is inserted. It grips the inner cortex and, when tightened, exerts great force to pull the outer segment into close contact with the inner one. This principle can be used in oblique sagittal mandibular fractures, with the placement of at least three screws, or in combination with the plate, lagging only one or two of the total minimum number of screws (Fig. 51.8).

#### **<IP_ADDRESS> Absolute Rigid Fixation Provided by Lag Screw**

Lag screw should be selected in patients having suffcient bone available for placement of two screws; dissolution of the bone around the screws results in cases of micromotion. The lag screw should be placed in the direction perpendicular to the line of fracture to avoid displacement or overriding during tightening of the screws.

Advantages of lag screws over bone plates:

#### Disadvantages

As the lag screw fxation relies on compression of bone fragments and if intervening bone is unstable due to comminution or missing, there will be segment overriding or fracture gap shortening, resulting in malocclusion.

#### **51.7.4 Comparison of Lag Screw Fixation Methods with Diferent Methods of Fixations** [17–19]

#### **51.7.5 Champy's System** [21]

Different treatment principles using monocortical miniplates without axial compression for treatment of mandibular and midface fractures were introduced, namely, by Michelet et al. in the late 1960s, which they published in 1973.

Michelet's work has been elaborated by Champy et al. for the management of mandibular angle fracture by the use of intraoral monocortical miniplates. The ideal line of osteosynthesis has been followed by Champy for plates fxation (Fig. 51.9).

It is based on the principle of neutralizing unfavorable traction strains while at the same time allowing transmission of favorable compression forces. The biomechanical validity of Michelet principles was confrmed in a series of multidisciplinary experiments performed in Strasbourg, France, between 1971 and 1974 [21].

#### **Advantages**

With this type of fxation, there is adequate stability to allow direct bony union and is called as functionally stable fxation. There are many fxation techniques used in oral and maxillofacial surgery (OMFS) which are not rigid fxation truly but classifed as functionally stable fxation.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.10** Champy's miniplate

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.9** Champy's ideal line of osteosynthesis

#### **<IP_ADDRESS> Materials**

Plates and screws are made up of pure titanium. The miniplates are 2 cm long, 0.9 mm thick, and 6 mm wide. They had an elastic limit of fexibility between 70 and 80 per square millimeter, and their rupture point lies between 95 and 110 decanewton (daN) per square millimeter (Fig. 51.10).

#### **<IP_ADDRESS> Miniplates** (Fig. 51.11)

#### **<IP_ADDRESS> Screw**

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.11** OPG showing fxation with the help of miniplates after Leefort I and bilateral sagittal split osteotomy

The drill has the same diameter as the core of the screws—1.6 mm. This ensures frm anchorage of the selftapping screws.

#### **<IP_ADDRESS> Biomechanical Properties of Screw**  (Fig. 51.12) [22]

– The external or the outer diameter ranges from 0.8 to 2.0 mm. Core diameter of the screw is its internal diameter. The surgical bone screws act by clamping the bone plate and bone together.

Self-drilling screw has a drilled-shaped point to cut and does not require predrilling. Self-drilling screws have several advantages over the self-tapping such as it does not require drilling the hole and prevents thermal damage leading to infection, screw loosening, osteomyelitis, and nonunion. It also prevents damage to tooth roots and nerves by the use of drills and also avoids the complications associated with drill bit fracture.

#### **<IP_ADDRESS> Monocortical vs. Bicortical Screws**

The monocortical screws are generally used for fxation of mandibular fractures and after sagittal split osteotomy. Chug H-IJ et al. [ 26] also concluded that monocortical screws provide stable fxation. Also chances of damage to the vital structure like inferior alveolar and lingual nerve are less with monocortical screws. Bicortical screws are usually used at the lower border of the mandible for fxation.

#### **51.7.6 Microplates**

The microplate fxation concept was introduced by Luhr in 1988. They are composed of cobalt, vitallium alloy, and molybdenum in the percentage of 68%, 27%, and 5 %, respectively. It has got excellent physical strength and corrosion resistance.

The thickness of plate is 0.5 mm, and the diameter of the screws is 0.8 mm. In all the three dimensions, they can be contoured and maintained an excellent degree of rigidity for osseous segment stabilization. They are used in:

#### **<IP_ADDRESS> Micromesh**

Inspite of its reduced thickness (0.3 mm), micromesh is remarkably strong. It is available in sizes of 40 by 60 and 60 by 100 mm. Template made of a soft, malleable tin alloy comes in various sizes. The template is cut to the shape and size required in the individual case, and then it is contoured to the bone surface. The actual titanium micromesh is then cut out with a wire cutter and contoured on the instrument table reduplicating the individual shape of the template.

#### **51.7.7 AO/ASIF System [27]**

The association of osteosynthesis/association for the study of internal fxation (AO/ASIF) were founded by a group of 15 Swiss surgeons in 1958. The group was led by Maurice E. Muller; AO/ASIF investigators have documented the biologic basis for the concepts on which rigid fxation techniques are based.

Spiessl applied AO/ASIF concepts of long bone healing and modifed AO/ASIF instrumentations for use in mandible in the late 1960s and early 1970s.

Compression can be achieved through static or dynamic means. The two devices that produce static compression are the self-compression plate and lag screw.

The EDCP (eccentric dynamic compression plate) has outer hole which is oblique causing compression on alveolar side and longitudinal inner holes creating basal side interfragmental compression. EDCPs eccentric action eliminates the need for tension band. This plate has most utility for simple fracture of the posterior region where there are no teeth available for splinting.

The reconstruction plate is a load-bearing plate and absorbs the entire functional load. They are designed for use without the tension band. It is large and reinforced version of basal stabilization plate. They can be adapted to local bony contours and are malleable. Depending on the placement of drill hole, it has two-way DC holes that enable compression to be applied in either longitudinal direction.

#### **<IP_ADDRESS> Plates**

	- (a) DCP plates
	- (b) EDCP plates

#### **<IP_ADDRESS> Dynamic Compression Plate (DCP)**

These are designed to withstand tensile loading force in the mandible. In mandibular angle, body, and symphysis regions, they can be used comfortably. It can be applied intraorally or through an extraoral incision. It is used with a tension band. The dynamic compression plate was developed in 1969.

The DCP has a self-compressing hole design. The holes are oblong, and the portion of each hole distant from the fracture has a sloping form or "shoulder."

Experimental work showed that the fat undersurface of the DCP interfered with the vascular supply of the underlying cortex onto which it was compressed by the screws. The concept of "footprint" is the area of undersurface of the plate in contact with the underlying bone cortex.

*Principles of DCP*—The sloping shoulder of the DCP hole has the form of part of an angled cylinder. If a screw is inserted eccentrically, so that its head on fnal tightening slides down the sloping profle of the hole, the screw/bone unit will be shifted toward the fracture, and the fracture plane will thereby be compressed. Such a screw is often referred to as a load screw.

#### **<IP_ADDRESS> Eccentric Dynamic Compression Plate (EDCP)** [27]

It produces a compressive force via arrangement of eccentric and centric (axial) plate holes. EDCP are 8 mm wide and come in four-hole (36 mm long) and six-hole (42 mm long) lengths. The stainless steel plates are 2 mm thick, and the titanium plate is 2.2 mm thick. At the fractures alveolar side, the compression has been provided by the 75° angulation. It is important to place the sloped edge of the angled hole at the mandibular lower border (if the plate is placed upside down, it will tend to distract bone edges at the alveolar border). First central screws are inserted in EDCPs (longitudinal hole eccentrically away from the fracture) than at the lower border; screws are placed in the 75-degree oblique holes eccentrically and in the last rest of the screws inserted in a neutral position. When the plates and tension band splint cannot be used, in those situations EDCP plates are used. The reduction forceps with pressure splinting are useful initially to reduce and compress the fragments when applying the EDCP plate.

#### **51.7.8 Bioresorbable Fixation Systems**

Use of titanium plates and screws is time-tested for their use in management of craniofacial fractures. However, it has many drawbacks including infection, hardware palpation and visibility, hypersensitivity to temperature changes, and stress shielding effect. They also interfere with radiographic examination. Sometimes, metal ions leach out into soft tissues. In view of these complications, bioresorbable implants were developed hoping to reduce hardware-associated complications as well as the necessity for hardware removal.

The use of bioresorbable fxation devices must be limited as their mechanical strength is inferior as compared to the titanium hardware. They can be effectively used in low loadbearing areas of maxillofacial skeleton like maxilla, zygoma, and upper regions of face. The bioresorbable system may not be strong enough to provide adequate stability in mandible fractures which are comminuted, as it is a load-bearing bone. It can be used in simple mandibular fractures.

Bioresorbable fxation systems stabilize fracture segments long enough for fracture healing and union to occur then dissolve, thereby reducing complications frequently encountered with metallic hardware such as palpability, visibility, cold sensitivity, and need for removal. Most commonly polylactic acid (PLA) is used in bioresorbable plates.

#### **Complications** [28]

#### **51.8 Recent Developments**

To reduce the stress shielding, reduction in modulus is the answer to correct the disadvantages of internal fxation. To improve the healing of the fracture under the plates, the only solution is to allow micromotion through the fracture site; the design should be made in such a way that it resists torsional, bending, and shear movements.

#### **51.8.1 Three-Dimensional (3D) Plates**

(Fig. 51.13)

The two miniplates are connected by interconnecting crossbars which are used as 3D plates. Technically, they are not three-dimensional structures, but their closed quadrilateral shape provides stability in all three dimensions.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 51.13** Orthopantomogram showing fxation with threedimensional plate

#### **51.8.2 Virtual Surgical Planning, Computer-Assisted Design, and 3D Modelling**

The management of the facial fracture is very challenging due to its unique three-dimensional contours and nonlinearity of facial skeleton. The recent development in the software technology and 3D modeling has revolutionized the treatment. They can be used as an adjunct to the standard preoperative preparation.

To reduce the operating time in the operation theater, the 3D models can serve as a template on which pre contouring of the fxation plates can be done. Custom-designed titanium implants can be made with the help of 3D printers to get the accurate ft. They can be preferred over the conventional implants and reduce the surgical time. The model design and virtual surgical planning help in constructing the guides which can be used perioperatively, can design the optimal approach preoperatively, and can compare the actual outcome to the virtual design. To reconstruct the multitude of craniomaxillofacial defects of mandible, zygoma, midface, and orbit, these technologies are very helpful. 3D modeling and computer-assisted surgical planning have been very helpful in managing the complications associated with these injuries.

#### **51.8.3 Intraoperative Imaging** [29]

Intraoperative imaging is very important in assessing the reduction and fxation of all maxillofacial fractures, and according to its feedback, the surgeons can immediately make corrections of any error that occur during reduction and fxation, which indirectly reduces the complications and avoids potential resurgeries. Computed tomography (CT) is commonly used for the same purpose.

#### **51.9 Conclusion**

For the treatment of maxillofacial fractures, many fxation methods have been used with great success. To reestablish the pre-injury esthetics, the normal masticatory function and the proper occlusion in cases of such fractures are the main objectives of the treatment. Maxillomandibular fxation can be done for the conservative management of such fractures which can be carried out with the help of arch bars, wiring, and cap splints and in edentulous patients by gunning splints. The open reduction and internal fxation can be carried out with the help of miniplates, microplates, 3D plates, and reconstruction plates. Different plating systems and wiring techniques make the management of these maxillofacial fractures predictable with high success rate.

**Acknowledgment** Author wishes to thank Dr. Anshul Rai for providing Figs. 51.6, 51.7, 51.11, and 51.13.

#### **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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## **Fractures of the Mandible**

### Anshul Rai

#### **52.1 Defnition**

A fracture is defned as "A breach in the continuity of bone."

#### **52.2 Introduction**

The mandible which is the only mobile bone of the maxillofacial region forms the lower third of the face. Owing to the prominence of the symphysis of the mandible, it is most vulnerable site to be traumatized during the road traffc accidents and, at the same time, most tempting site to be hit during the assault. Thus, the fractures of the mandible are one of the most common in maxillofacial area. It also affects the social life of the patients (Box 52.1).

The word "mandible" derives from the Latin word mandere "to chew" and -bula (instrument) which literally translates to mandibulaie "instrument used for chewing."

The bone is formed in the fetus from a fusion of the left and right mandibular prominences and the point where these sides join, the mandibular symphysis. Like other symphysis in the body, this is a midline articulation where the bones are joined by fbrocartilage, but this articulation fuses together in early childhood.

**Electronic Supplementary Material** The online version of this chapter (https://doi.org/10.1007/978-981-15-1346-6\_52) contains supplementary material, which is available to authorized users.

#### **Box 52.1: General Efect of Mandible Fracture on Social Life [1]**

#### **52.3 Surgical Anatomy**

The mandible is a horseshoe-shaped only mobile bone of the facial skeleton. It is the strongest bone with thick cortices. Symphysis is the most prominent part of mandible, and the condyles articulate with glenoid fossa of temporal bone. The inferior alveolar neurovascular bundle passes through the bone, and in the case of fracture, it may get traumatized and can lead to hematoma and neurological defcit.

#### **52.3.1 Angle of the Mandible**

By defnition, there are three types of angle as described below:

**52**

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 1053

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_52

A. Rai (\*)

Department of Dentistry, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India e-mail<EMAIL_ADDRESS>
Anatomically, mandibular angle is a weaker structure compared to other anatomic subsites.

#### **52.3.2 Canine Region of the Mandible**

In the canine area, also the mandible is weaker as the canine has the longest and the strongest root, and it occupies lot of space in the bone and undermines and weakens it. Thus, the mandible has a tendency to fracture at this site.

#### **52.3.3 Symphysis and Parasymphysis of Mandible**

#### **52.4 Classifcation**

The general classifcation of fractures of bone is described in Table 52.1.

#### **52.4.1 Classifcation of Mandibular Fracture According to Site** (Fig. 52.1)

Figure 52.1 highlights the mandibular fracture according to site of fracture with its incidence [2].

#### **52.4.2 Classifcation of Mandibular Fracture According to the Impact**

According to the impact on bone, fracture can be classifed as direct fracture and indirect fracture.

During an impact, the force on the cortex results in compression, and the other cortex undergoes tension. If the force of the impact is more than the compressive and tensile strength of the bone, the bone fractures.

In a similar fashion, when there is an impact, the point of application of force gets compressed, and the resultant vector travels along the bone and applies tensor force on the point intersected by this vector. The fracture at the site of impact is called **direct fracture**, and the fracture at the site of intersection with the vector is **indirect fracture**.

For instance, the force applied to the symphysis menti results in a direct fracture at the symphysis. The vector travels to the condylar necks bilaterally and induce indirect fractures

**Fig. 52.1** (**a**, **b**) Highlights the mandibular fracture according to site of fracture with its incidence

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 52.2** 3D CT showing parasymphysis and bilateral condyle fracture

**Table 52.2** Combination of mandibular fractures

of subcondylar areas bilaterally, as the condylar necks are weak. This is called a "tripod fracture" (as the fracture is at 3 points) or "parade ground fracture" or "guardsman's fracture." The later terms are used because these fractures are commonly seen among soldiers who stand upright on the parade ground for a long time. When they faint, they fall on their chin resulting in symphysis and bilateral condylar neck fractures.

### **52.4.3 Combination of Fracture**

The most common mandible fracture seen in the developed countries is angle fracture combined with contralateral body or symphysis of the mandible [3]. Table 52.2 and Figs. 52.2, 52.3, and 52.4 highlight various combinations of direct and indirect fractures in the mandible.

### **52.4.4 Classifcation of Mandibular Fracture According to Displacement**

The fracture fragments are liable to displacement according to unfavorable muscle pull leading to diffculty in the management of these displaced fractures. Table 52.3 highlights various muscles attached to the mandible with their actions.

According to the displacement of fracture fragments due to muscle pull, the fracture can be classifed as:

When viewed from superior aspect:

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**Fig. 52.3** Showing right parasymphysis and left condyle fracture

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**Fig. 52.4** Showing right body and left angle fracture

lingually due to the pull of the medial pterygoid muscle; thus there will be separation of the fragments in the buccolingual plane due to the unfavorable muscle pull, and the fracture is said to be vertically unfavorable (Fig. 52.5b).

When viewed from buccal aspect:

**Table 52.3** Muscle attachments over the mandible with their actions

#### **52.5 Clinical Features**

The clinical features of the fractures are described in Table 52.4 (Figs. 52.7, 52.8, 52.9, 52.10, 52.11, 52.12, 52.13, and 52.14).

#### **52.6 Clinical Examination**

#### **52.6.1 Bimanual Palpation**

The abnormal mobility at the fracture site can be elicited by the bimanual palpation. The mandible is grasped on either side of the suspected fracture line in such a way that the index fnger is on the occlusal surface of the teeth and the thumbs are on the inferior border. The proximal and distal segments are moved in supero-inferior and anteroposterior direction, to elicit abnormal mobility (Fig. 52.15).

#### **52.6.2 Compression Test**

When there is a hairline, undisplaced fracture of the mandible especially at the symphysis or angle or in the subcondylar areas and it is not conspicuous clinically and radiologically, a compression of the mandible at the symphysis area and both the sides over the body, using both the palms by the operator, elicits tenderness which may suggest the fracture (Fig. 52.16a, b).

#### **52.7 Radiographic Examination**

As a rule, in orthopedics, the X-ray must be taken in two planes perpendicular to each other, i.e., in the anteroposterior and mediolateral. The most common radiographs to detect fracture of the mandible are:

**Fig. 52.5** (**a**) Vertically favorable. (**b**) Vertically unfavorable

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**Fig. 52.6** (**a**) Horizontally favorable. (**b**) Horizontally unfavorable

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**Fig. 52.7** Swelling in angle region after fracture

#### **52.7.1 Are Postoperative Radiographs Necessary?**

The answer is no. The reasons behind this is:

However, the postoperative radiographs are required in few cases of:

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**Fig. 52.8** Diffculty in mouth opening due to displacement and deviation of fracture

Bergh van den et al. [6] also suggested that postoperative radiography is not necessary. The advantages of avoiding postoperative radiographs are:

#### 52 Fractures of the Mandible

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**Fig. 52.9** Hematoma in the angle region

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**Fig. 52.11** Discoloration of skin

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**Fig. 52.10** Presence of abrasion, contusion, or laceration

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**Fig. 52.12** Visible step deformity in cases with displacement of fractured segments

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**Fig. 52.13** Malocclusion

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**Fig. 52.15** Bimanual palpation

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**Fig. 52.14** Sublingual hematoma (Coleman's sign)

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**Fig. 52.16** (**a**, **b**) Vertical and horizontal compression test

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**Fig. 52.17** OPG demonstrating parasymphysis and contralateral condylar fracture

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**Fig. 52.18** PA view mandible showing left mandibular angle fracture

**Fig. 52.19** Computed tomography (CT) scan demonstrating displaced left para median fracture

> Once the basic Airway, breathing, circulation (ABC) in the emergency management has been secured, the suturing of the extra-/intraoral wounds and initial stabilization and immobilization of the fracture fragments are important. Box 52.2 shows

**52.8 Emergency Management (refer Chap.**

**Fig. 52.21** Cone beam computed tomography (CBCT) demonstrating

**48 of this book)**

displaced right para median fracture mandible

advantages of immobilization of fracture fragments.

Initial stabilization and immobilization is done by:

#### 1. **Bridle wiring (refer Chap. 50 of this book)**

It is a type of temporary stabilization and reduction of the fracture fragments of the dentate segment with the help of 24- or 26-gauge wires under local anesthesia.

The wire should be wrapped around two healthy teeth adjacent to the fracture line; if the tooth adjacent to the fracture are mobile, the wire should be wrapped around the second tooth adjacent to the fracture (Fig. 52.22a, b).

#### 2. **Supportive bandage**

These bandages are commonly used to temporarily stabilize the fracture of the lower jaw. Small crepe bandages can be used for mandible fracture.

**Fig. 52.20** Digital visual tomography (DVT) demonstrating comminuted right body fracture

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**Fig. 52.22** (**a**, **b**) Temporary stabilization of a grossly displaced bilateral body fracture by bridle wiring

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**Fig. 52.23** Barrel bandage

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**Fig. 52.24** Four-tailed bandage

### **52.9 Goals of Treatment of Mandibular Fracture** (Table 52.5)

#### **52.10 Treatment Options for Diferent Sites**

**52.10.1 Closed Reduction** (Table 52.6)

#### **52.10.2 Clinical Tip**

Wiring techniques required use of multiple wires. These wires cause inadvertent fnger puncture to the operator's fngers and increases the risk of spread of blood-borne diseases like HIV and hepatitis. To avoid such complication, Rai [7] recommended the use of dynaplast adhesive tape over all fngertips before wearing sterile gloves while doing Maxillomandibular Fixation (MMF) (Fig. 52.25).

#### **52.10.3 Open Reduction** (Table 52.7)

#### **52.10.4 Steps in Open Reduction Internal Fixation (ORIF) of Mandible Fracture**

1. Incision (extra-/intraoral) (Fig. 52.26a, b).

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**Fig. 52.25** Finger protection before wiring

According to Dimitroulis [8] MMF is unnecessary in undisplaced angle fracture if there is a skilled assistant present to assist and help manually reduce the fracture fragments for plating. Author also believes that many undisplaced, single fracture of mandible can be fxed without MMF when two skilled surgeons operate the case.

#### **52.10.5 Symphysis and Parasymphysis Fracture** (Video 52.1)

Various internal fxation techniques were mentioned in the literature for both symphysis and parasymphysis fractures [9]. They are enumerated in Table 52.8.

Note: Readers has to refer Chap. 51 on plating systems to know the principles of osteosynthesis, tension banding, zone of compression/tension, etc.

Fixation with two miniplates is widely used for the fxation of symphysis and parasymphysis fractures (Fig. 52.31). Some authors preferred use of two lag screws (Fig. 52.32a, b) for the fxation of symphysis fractures, but their uses are less in comparison to two miniplates because they are technique sensitive. Three-dimensional plates require less manipulation and adaptation which indirectly reduce the operating time

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**Fig. 52.26** (**a**, **b**) Extraoral sub mandibular incision and intraoral vestibular incision

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**Fig. 52.27** Exposure of the fracture site (left paramedian mandible via vestibular incision)

(Fig. 52.33), but use of it is questionable when fracture fragments are multiple even in isolated symphysis fractures.

Usually, an intraoral approach is preferred for management of symphysis and parasymphysis fractures. However, if an existing laceration or scar is present, it should be utilized for exposure of fractured segments and subsequent management (Fig. 52.34).

#### **52.10.6 Parasymphysis Fracture**

3. One miniplate above and another below the mental nerve used for fxation of parasymphysis fracture (Fig. 52.35).

### **52.10.7 Mandibular Angle**

The prevalence of angle fractures ranges from 16.5 to 37 % in the literature. Presence of third molar (3M) increases the chance of angle fracture by 3.27 times, and class II-B positions of 3M are the most favorable for angle fracture, while class I-A act as protective factors [10].

### **<IP_ADDRESS> Impact of Presence or Absence of Impacted Mandibular Third Molar (IM3M) on Angle and Condylar Fracture**

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**Fig. 52.28** (**a**–**c**) Reduction of the fracture (with the help of bone holding forceps)

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**Fig. 52.29** (**a**, **b**) Use of chin retractor in reduction of fracture fragments

#### **<IP_ADDRESS> Open vs. Closed Reduction**

Closed reduction is advisable for patients who are medically unft for surgery (due to any reasons) or those who did not give consent for open reduction internal fxation (ORIF).

#### **<IP_ADDRESS> Approaches for ORIF**

Intraoral incision is advocated for ORIF with single miniplate, but higher infection rate of 13% was reported in comparison with 2% when extraoral incision was used for plating. Marginal mandibular nerve showed weakness in 8% of cases, and it sometimes has prominent extraoral scarring in patients treated with extraoral approach [14] .

Sugar [15] concluded that the combined use of transbuccal and intraoral approach is safe and effective than the intraoral approach alone for ORIF. Author too prefers the same approach.

#### **<IP_ADDRESS> Advantages of Transbuccal Approach** [16]

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**Fig. 52.30** Application of pressure bandage

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**Fig. 52.31** Fixation bilateral paramedian fracture mandible with 2 miniplates each on either side

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**Fig. 52.32** (**a**, **b**) Fixation left para median fracture mandible with lag screws

#### **Position of Trocar Placement** [17] (Fig. 52.37)

Gulses et al. described a safe zone to place the trocar in the form of a triangle created by drawing three lines on the face.

Line 1: At the lower border of mandible (mandibular line)

**Table 52.8** Various fxation techniques for anterior mandibular fracture

Through a small stab incision, a blunt dissection is performed with dissecting scissors till the mandibular periosteum is torn and the trocar is placed through the dissected channel.

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**Fig. 52.33** Fixation of anterior mandible with three-dimensional plate

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**Fig. 52.35** One miniplate above and another below the mental nerve used for fxation of parasymphysis fracture

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**Fig. 52.34** (**a**–**c**) Existing laceration has been used as access for fxation of the anterior mandible fracture

Various techniques are mentioned in the literature for internal fxation of angle fracture (Box 52.3) [18]:

#### **<IP_ADDRESS> Single vs. Two Plates vs. 3D Plates**

**Al Moraissi** [19] in a meta-analysis showed that the incidence of wound infection, dehiscence, hardware failure, and overall complications were less in patients treated with one miniplate on external oblique ridge in comparison to two.

**Ellis III** [20] also advocated use of single miniplate on superior border because:

#### **Box 52.3: Fixation Techniques for Angle Fracture**

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**Fig. 52.36** Intraoral incision for exposure

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**Fig. 52.37** Transbuccal approach used for fxation of angle fractures

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**Fig. 52.38** Fixation of mandibular angle fracture using single miniplate

– If infection occurs, retrieval of single miniplate can be done under local anesthesia in a clinic, but two plates commonly required general anesthesia which indirectly increases the cost and prolonged the hospital stay.

**Rai et al.** [21] also conclude better results with two-plate fxation. Second miniplate is supposed to increase stability and protects the fracture site against torsion and bending. 1070

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**Fig. 52.39** Fixation of mandibular angle fracture using two miniplates. (**a**) Clinical picture, (**b**) orthopantamogram

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**Fig. 52.40** Fixation of mandibular angle fracture using 3D plate. (**a**) Clinical picture, (**b**) orthopantamogram

Theoretically second plate establishes a second line of osteosynthesis.

**Levy et al.** [22]advocated two-plate fxation superior for ORIF of angle fracture. According to them two miniplates provide better stabilization and have reported lowest complication rate in comparison to any other plating technique.

**Wusiman et al.** [23] demonstrate that three-dimensional (3D) miniplates provide better fxation than standard miniplates. It also provides simultaneous stabilization of tension and compression zones with lower incidence of postoperative complications and good results. According to Zix et al. [24] 1-mm-thick 3D plate is as stable as 2 mm miniplates, and it offers better bending stability and more resistant to out of plane movement or torque.

**Ellis III and Ghali** [25] used lag screws for treating mandibular angle fractures but reported very high incidence of postoperative infection and bone exposure. Also the fxation of angle with lag screws is technique sensitive and requires expertise.

**Kang and Zide** used seven-hole angle plate when Champy technique is ineffective and more rigid or semirigid fxation is required [26]. According to them seven-hole angle plate is fxed through transfacial trocar and stabilized intraorally. On the other hand, Champy plate required bending, lacks rigidity, diffculty in screw hole drilling, inaccurate centric placement of screws.

#### **<IP_ADDRESS> Extraction vs. Retention of IM3M in Angle Fracture**

The use of postoperative MMF and extraction versus retention of teeth in the line of fracture did not infuence any of the outcomes [27]. Increase rate of infection by extraction of a tooth was found in the study by Ellis and Walker in 1994 [28]. However, in another study published in 2002, Ellis [29] reported an increased incidence of infection if teeth were left in the line of fracture. Author advocates extraction of 3Ms at the time of ORIF for better results.

#### **52.10.8 Body Fracture**

A single four hole with gap miniplate (Fig. 52.41) below the root apex and the inferior alveolar canal is suffcient for fxation of body fracture of mandible through the intraoral approach most of the times, except when a patient is having

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**Fig. 52.41** Fixation of body fracture with single miniplate

extraoral soft tissue injury/scar or having severely comminuted fracture fragments.

#### **52.10.9 Ramus Fracture**

Mandibular ramus (MR) fracture occurs rarely and ranked third least common fracture after alveolar and coronoid fracture [30]. MR fractures are very rare in isolation. It can be horizontal or vertical. Its incidence ranges from 0.9 to 5.5% [31]. Isolated ramus fracture can be managed by closed reduction, but ORIF is the treatment of choice when it is associated with other maxillofacial fractures. To correct the facial height when midface is also fractured, the vertical rami become the only determinant, and re-establishment of these buttresses is very important before repositioning the crushed midfacial bones [32] (Fig. 52.42a–c).

#### **<IP_ADDRESS> Management of Triangular Fragments (TF) at the Lower Border**

Heslop et al. [33] advocated repositioning of TF if they are attached to the muscle or periosteum and remove them if they are very small or detached from the periosteum.

According to Blinder et al. [34] to prevent infection and preserve vascularization, TF should be unexposed and unreduced. TF should be sandwiched between the two fracture lines by rigid fxation without exposure, and preserving vascularization may be the treatment of choice

TF of bone at the angle region were more often shown to get infected in comparison to body, symphysis, or parasymphysis because thick, better vascularized, and more cancellous bone presents in these areas as compared to angle region. It's better to remove small fragments in the angle region to avoid postoperative discomfort.

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**Fig. 52.42** Management of mandibular ramus fracture. (**a**) DVT showing mandibular ramus fracture, (**b**) fxation using two miniplates, (**c**) postoperative orthopantamogram showing fxation of mandibular ramus and midface fractures (blue arrows point to lower border plates and green arrows point to upper border plates)

#### **52.10.10 Coronoid Fracture**

It generally occurs in combination with other fracture of the mandible (Fig. 52.43a), and with zygomatic complex fracture (commonly with arch) (Fig. 52.43b), rarely does it occur in isolation. It can be treated by extraoral or intraoral approaches. Later, having low incidence of facial nerve injury and no facial scar. Coronoid fracture ranges from 0.6 to 4.7% of all facial fractures and 1–2.9% of all mandibular fractures [35].

It manifests as [36, 37]:

#### **<IP_ADDRESS> Indications for Conservative or Open Reduction of Coronoid Fractures**  (Table 52.9)

Conservative management in the form of soft diet and mouth opening exercises to avoid bony adhesions to the surrounding structures [38]. If patients are treated with MMF and trismus occurs, it can be managed by removal of the coronoid process [39].

#### **52.10.11 Bilateral Fracture of Mandible**

Over half of the mandibular fractures are bilateral; in the case of angle fracture, most of the times, it occurs in combination of contralateral mandibular body and symphysis [40]. ORIF is the treatment of choice most of the times.

Clinical Tip: An MMF screw can be effectively used for reduction of a bilateral mandibular fracture by placing the screw in the symphysis region. A wire is passed through the screw, and the fracture segment can be manipulated for reduction (Fig. 52.44).

**Table 52.9** Indications of closed and open reduction for coronoid fractures

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**Fig. 52.43** Coronoid fracture (**a**) associated with condylar fracture, (**b**) associated with zygomatic arch

#### **52.10.12 Comminuted Mandible Fractures**

Comminution is defned as presence of multiple fracture lines in many small pieces within the same area of mandibular angle, body, ramus, and symphysis [41]. This type of fracture rarely occurs in the condyle region. In a comminuted fracture, bone is "crushed, broken, splintered" into number of pieces, creating multiple small fragments (at least two free segments of bone) (Fig. 52.45a, b).

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**Fig. 52.44** Use of MMF screw in reduction of bilateral parasymphysis fracture

To fx small fragments, multiple options are mentioned in the literature like miniplate, microplate, screws, steel wires, and absorbable sutures. A fragment larger than 1 cm should be conserved, reduced, and fxed [42].

Ellis et al. [43] advocated that more complications are associated with multiple fragment fractures in comparison to fractures having few segments. Therefore, comminuted fractures need load-bearing fxation.

The bone fragments will not provide buttressing to help stabilize the fracture; therefore surgeons operating comminuted mandibular fractures having two or more free bone fragments and/or requiring bone fragment removal should opt for reconstruction plates. Miniplates can be used when comminuted mandibular fractures have only one free bone fragment. Combination of reconstruction and miniplates can be used when multiple small fragments are there in comminuted mandible fracture (Fig. 52.46). Implants used for fxation of comminuted fractures are mentioned in Box 52.4.

Use of reconstruction plates required expertise and it is time-consuming. Sometimes contour is also not favorable

#### **Box 52.4: Implants Used for Fixation of Comminuted Fractures**

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**Fig. 52.46** Combination of reconstruction and miniplates in management of comminuted fractures

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**Fig. 52.47** Postoperative elastics for correction of minor occlusal discrepancies (Inter maxillary elastics- IME)

which can create slight malocclusion but can be managed by postoperative elastics and selective occlusal adjustments (Fig. 52.47).

Dia et al. [44] used titanium mesh for the treatment of comminuted mandible fracture with successful results. According to them mesh required little soft tissue exposure, had low infection rate, and provides favorable mandibular morphology.

#### **52.11 Inferior Alveolar Nerve (IAN) Injury in Mandible Fracture**

According to the literature, the incidence of IAN injury was [45]:

The neurosensory testing was done both before and after the treatment of mandibular fracture in which nerve injury is suspected. Two-point discrimination and pinprick testing can be used to assess the level of IAN injury. Preoperative knowledge of the patient's IAN position (based on CT/CBCT) is very important in decision-making regarding fxation position of the fracture fragments with miniplates. Plating should be done above or below the course of IAN. ORIF in the area of IAN takes longer duration to normalization of sensation, and it ranges from 1 week to 12 months. Postoperative CT/CBCT is mandatory if operating surgeon suspected the impingement of screw on the IAN or no relief of sensation after 6 weeks of ORIF for further management. Surgeons should not hesitate to redo the surgery in cases of IAN injury by miniplates and screws.

#### **52.12 Geriatric Mandibular Fracture**

With old age, the incidence rate of maxillofacial fracture increases, with mandibular fracture appearing with a greater frequency. As the age advances, the weakening of the mandible occurs due to:

The most common mechanisms of injury in geriatric patients are [46]: