**Fig. 69.19** The septal osteotomy is completed from the anterior nasal spine through the vomer bone posteriorly, with the guarded prongs on the septal osteotome angled inferiorly. Care is taken to retract the nasal mucosa to minimize injury and bleeding to the soft tissue. The right maxilla has been removed to show the desired cross-section clearly

#### **69.4.5 Down-Fracture and Mobilization**

Once the osteotomy cuts have been completed, some mobility should be readily evident, and down-fracturing be easily

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**Fig. 69.20** (**a**, **b**) (**a**) Once the maxilla is mobilized, the nasal mucosa can be completely freed from the maxilla in the piriform rim region, (**b**)

The greater palatine nerve and artery can be visualized and protected

during posterior bone removal from the lateral nasal wall area (yellow arrows) (also see Fig. 65.12a)

done with either bilateral manual digital pressure in the canine fossa or with instrumentation support at the piriform rim. Slowly separate the maxilla by pulling the anterior portion inferiorly while observing the nasal mucosa to avoid tears. If signifcant resistance is encountered, revise the osteotomy cuts thoroughly to ensure complete separation. To avoid complications related to pterygomaxillary disjunction, we prefer to extract maxillary third molar and make a vertical osteotomy cut through the socket connecting the horizontal cut on the posterolateral surface of maxilla.

Precious et al. (1991) did a study of 138 consecutive Le Fort I osteotomies with successful down-fracture of the maxilla by digital pressure alone (with no serious complications except transient epistaxis that responded to local packing) [59, 60].

Once the down-fracture is completed, place a Seldin elevator or tongue depressor behind the tuberosity, and pull the posterior maxilla forward. This will fully mobilize the maxilla from its attachments. For large advancements, freeing the tissue from the nasal side of the posterior maxilla in the soft palate area will provide signifcantly more forward mobility. In addition, in repeat maxillary surgery, mobilizing the maxilla will most likely be more diffcult, and time must be spent freeing hard and soft tissue attachments to ensure passive movements and surgical stability.

#### **69.4.6 Removal of Posterior Interferences**

Removal of posterior interferences should be done immediately after down-fracture which will make it easier to set the maxillary position later. The maxillary bony septum is reduced most easily with a bur. The lateral nasal wall can be reduced with a rongeur, bur, or reciprocating saw. While protecting the descending palatine nerve and artery with a curved freer (Fig. 69.20a, b), the pyramidal process of palatine bone is most safely reduced with the reciprocating saw or bone fle. Sometimes a thin spatula osteotome can be used. Finally, the posterior tuberosity, anterior pterygoid plate, and posterior lateral maxillary wall can be reduced with a bur or reciprocating saw (Fig. 69.21). If the superior movement of the maxillary is more that 6 or 7 mm, a partial inferior turbinectomy may be indicated to allow a passive impaction. The nasal mucosa is incised with a scalpel blade along its inferior surface in an anterior-posterior direction. The inferior half of the turbinate is grasped with a large curved hemostat, and a dean scissor is used to excise this portion. Complete removal of the inferior turbinate is rarely necessary and can result in unpleasant clinical side effects. Electrocautery is used to coagulate the incised edge of the turbinate to minimize bleeding. The nasal mucosa is then sutured with a running 4-0 vicryl suture.

#### **69.4.7 Placement of Surgical Guide**

A prepared surgical guide is necessary to ensure accurate positioning of the maxilla. The guide is generally ligated to the upper teeth with 26–28 gauge wire. The upper and lower teeth are then wired together with 26–28 gauge wire, elastics, or power chain (Fig. 69.22).

#### **69.4.8 Removal of Anterior Interferences**

With the maxilla now fxed to the mandible, it is rotated into position by applying posterior and superior pressure on the

**Fig. 69.21** Posterior interferences are initially removed from the posterior septum, lateral nasal walls, pyramidal processes of the palatine bones, and lateral maxillary walls. This allows for passive seating of the maxilla without posterior pivoting

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**Fig. 69.22** Placement of surgical guide and achieve desire stable occlusion. The lefort I osteotomy and AMO cuts are visible

mandible. To properly rotate the mandible, the surgeon places two fngers at the gonial notch regions of the mandible and the thumb of the same hand at the chin. Upward pressure is exerted with the two fngers at the gonial notches, and the thumb exerts a posterior and downward pressure. This "triangular" fnger formation ensures full seating of the condyles during mandible rotation and maxillary positioning. The surgeon then rotates the mandible and maxilla upward, keeping pressure on the two fngers and thumb (Fig. 69.38a–c). Upward rotation is

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**Fig. 69.23** The maxilla is rotated into place and anterior interferences are removed to ensure full seating of the condyles at the desired vertical position. Seating of the condyles of the mandible is achieved with superior pressure at the gonial notches and posterior pressure at the chin. Once the correct vertical maxillary positioning is achieved, the mandibular-maxillary complex can be reproducibly rotated with the condyles in the fossa without any bone or soft tissue pre maturities (Also see Fig. 69.12a, b)

stopped as soon as the frst contact is detected, and this interference is reduced accordingly. Anterior interferences can be easily reduced with a bur. The caliper is used to check the vertical distance from the anterior brackets to the K-wire and interferences are reduced accordingly. Closely observe the nasal septum for early inferences and deviation. When all the bony interferences have been completely removed, utilizing the "triangular" fnger formation, the mandible and maxilla can be easily rotated up into a stable reproducible position, with the condyles fully seated (Fig. 69.23).

#### **69.4.9 Fixation, Grafts, and Final Measurements**

With the maxilla positioned, four miniplates are accurately bent to passively ft across the osteotomy in the piriform and anterior buttress areas of the maxilla. Typically, there are two fxation holes above and below the osteotomy in each bone plate, for placement of four screws. Thin bone or large bone gaps may require more fxation screws in each plate or even require additional plates. Bone grafts can be adapted into the 1528

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**Fig. 69.24** (**a**, **b**) (**a**) Rigid fxation with four plates provides vertical and horizontal stability to the maxilla. The nasal septum should be free of deviation, and the occlusion should be reproducible once interdental fxation is released. Bone plates are used to stabilize the osteotomy bilaterally at the nasomaxillary and zygomaticomaxillary buttress

areas. (**b**) Autogenous bone grafts have been adapted and fxated in the osseous gaps to optimize bone healing and minimize postsurgical relapse. Grafting may be indicated in complex movements, especially large advancements and down grafting cases (yellow arrow)

osteotomy gaps, and press-ft into position, or rigidly fxed if necessary [61]. Once the fxation has been competed, fnal measurements with calipers are made to confrm proper vertical placement (Fig. 69.24a, b).

#### **69.4.10 Checks to Be Made Before Plate Fixation of the Maxilla**

Once the maxillary fxation is completed, the intermaxillary fxation is released. The mandible is hinged with the condyles fully seated using the "triangular" fnger formation. Retractors should be used to hold the cheeks away from the posterior teeth, and the mandible is rotated upward such that the teeth ft into the maxillary splint. The tongue is also manipulated out of the way if it is interfering with closure. There should be a smooth closure into the splint without any shifting or deviation of the occlusion. Contact should occur simultaneously in the anterior and posterior areas.

#### **69.4.11 Closure**

Proper closure occurs in three steps.

#### **<IP_ADDRESS> Nasal Cinch Suture (Alar-Base Suture)** [62]

With the dissection and exposure of the paranasal musculature during Le Fort I osteotomy, the nasal cinch suture provides appropriate repositioning of the soft tissue to minimize postoperative nasal base widening. A slowly resorbing suture (e.g., 2-0 polyglycolic acid) is placed from an intraoral approach into the alar base bilaterally, pulling the alar bases toward each other when tightened (Fig. 69.25a, b). If properly done, tightening should result in an equal or shorter alar base width when compared to the preoperative width. This will frequently result in an immediate upturned appearance of the nose, a protruded positioning of the upper lip, and edema. These immediate changes are transient and will disappear within a few weeks. Following healing, the procedure results in minimal widening of alar base from the preoperative measurement (Fig. 69.26a, b).

#### **<IP_ADDRESS> V-Y Closure** [63]

Typical movements of the maxilla and normal healing of the circumvestibular incision can result in lip shortening,

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**Fig. 69.25** (**a**, **b**) An alar base cinch suture controls the alar base width and counteracts postsurgical widening of the alar base. Care is taken to correctly place the suture in the fbro adipose tissue and transverse nasalis muscle at the lateral nasal base, allowing medial positioning of the alar base during suture tying (yellow arrow)

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**Fig. 69.27** Vestibular soft tissue closure is performed with a running resorbable suture. A midline V-Y closure provides support to the upper lip and rolls the vermillion upward and outward, gives fullness to the lip, and makes a prominent white-roll. Closure is started posteriorly and moved anterior to bring the labial side mucosa forward, which is then, closed in the midline in the form of an inverted "Y" (yellow arrow)

**Fig. 69.26** (**a**, **b**) Measuring the alar base pre-surgically (**a**) and post-surgically (after edema subsides and soft-tissue settles) (**b**) and confrming that the size remains same

lip thinning, and decreased vermillion show. The Le fort I incision transects various components of the midface musculature, including the transverse part of the nasalis muscle, the myrtiformis muscle), and the levator anguli oris muscle.

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It is important to correctly suture the deep muscular layers in proper anatomic orientation, so that the facial contour may be maintained [64].

The V-Y closure is performed to combat these undesirable changes. With the use of a skin hook, the tissue of the midline vestibular incision is grasped and pulled superiorly. Using a resorbable suture (e.g., 4-0 vicryl), the incision is closed vertically by grasping the tissue 1 cm away from the midline on either side of the skin hook and advancing these edges together by tightening the suture. This provides for a 1 cm V-Y closure. The remaining closure is completed with either a continuous suture or interrupted sutures. The closure generally requires four or fve throws of the suture (Fig. 69.27, Fig. 69.9b).

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**Fig. 69.28** (**a**, **b**) A case of vertical maxillary excess treated with superior positioning of the maxilla showing frontal, right lateral and left lateral views. (**a1, a2, a3**) Pre-surgical photos of the patient; (**b1, b2,**

#### **<IP_ADDRESS> Vestibular Closure**

The remaining vestibular closure continues from the posterior portion of the incision. A running resorbable suture (e.g., 4-0 vicryl) is passed in a simple running fashion. Figures 69.10, 69.11, 69.28a, b, 69.29a, b, 69.30a, b and 69.32a, b depict the results achieved by the technique described above for different clinical indications. Figure 69.31 demonstrates steps involved in peforming a Lefort I osteotomy in a bimaxillary setting.

**b3**) post-surgical photos of patient (Also see Figs. 69.29 and 69.39 for the full case series images)

#### **69.5 Quadrilateral (Quadrangular) Osteotomy**

This high-level osteotomy is a variant of the Le fort I osteotomy and extends up to the lower part of the zygoma, to a point just below the infraorbital nerve bilaterally.

The indications for this osteotomy are midface retrusion, including excessive scleral exposure.

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**Fig. 69.29** (**a**, **b**) (**a1, a2, a3**) Pre-surgical occlusion of the same patient as in Fig. 69.28, treated with LeFort I superior repostioning. (**b1, b2, b3**) Post-surgical occlusion of the same patient

The benefts of the quadrangular osteotomy are that it improves the appearance of midfacial retrusion and fattening and improves zygomatic prominence and support for the lower eyelid. This osteotomy has minimal surgical morbidity and has acceptable outcomes. This may therefore be considered, especially in Asian patients, as a viable treatment alternative for midfacial advancement without augmentation of the malar region [65].

If the cuts are made from high to low a signifcant inferior movement of the maxilla can be achieved thus reducing the necessity for an interpositional bone graft (which would be required following a maxillary set down) and alloplastic onlay grafts for the zygomatic regions. It is more stable than conventional inferior positioning of the maxilla as there is good bone contact with native bone and no bone graft. This osteotomy also produces less rotation of the nasal tip than the conventional Le Fort I osteotomy. However, it is important to recognize that if there is a mild facial asymmetry in the maxillary region, this asymmetry can be emphasized with this high-level cut as the maxilla is advanced. The surgical technique is the same as for the conventional Le Fort I osteotomy, but signifcant sharp dissection of the masseter muscle from

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**Fig. 69.30** (**a**, **b**) Patient with maxillary occlusion cant and asymmetry (also see Figs. 69.31, 69.32 and 69.40)

the zygoma is required to expose the prominence of the zygomatic bone. The bony cuts are demonstrated in Fig. 69.33. The cuts are made just below the infraorbhital nerves.

The bone over the zygomatic prominence is thick, and control over the shape of the cuts is easier using a burr and a saw. This ensures that the bony cut does not propagate upward to the cranial base but instead is directed downward to the normal pterygomaxillary disjunction level. The other steps to complete the bony cuts and down-fracture the Le Fort I cut are made as above. Fixation is with miniplates. However, care must be taken to ensure the plates are not palpable in the infraorbital regions.

#### **69.6 Surgically Assisted Rapid Palatal Expansion (SARPE)**

SARPE is a combination of orthodontic and surgical techniques to expand the maxillary arch. This is ideal in patients with of transverse maxillary defciency, where the palatal suture has completely fused. This concept initially was met with skepticism but later was repopularized through the works of several clinicians, including Issacson and Ingram [66] and Haas [67], as a viable method of treating maxillary transverse defciency. SARPE is indicated in cases where skeletal maturity has been achieved, transverse maxillary defciency is present, excessive display of buccal corridors when smiling, and presence of anterior dental crowding. It has been shown that the midpalatal suture undergoes ossifcation at a wide range of ages [68]. In general, SARPE is recommended for patients who are over 16 years of age [69]. Nonsurgical expansions can be a reasonable consideration for patients younger than 12 years of age.

Before starting the surgery, it is important to confrm the secure placement of the appliance and also the presence of the device key to activate the appliance.

This procedure follows Le Fort I single piece osteotomy. The maxilla is *not* down-fractured. Relieving of the osteotomies present at the zygomaticomaxillary buttresses is done, as this allows clearance during separation. The midline

**Fig. 69.31** (**a**–**m**) Surgical procedure for correcting the maxillary occlusion cant (also see Figs. 69.30, 69.32 and 69.40). (**a**–**c**) Sagittal split osteotomy cuts. (**d**) Incision marking for le fort Osteotomy. (**e**, **f**) Osteotomy cuts marked and made for asymmetric superior repositioning of maxilla. (**g**) Down-fracture of maxilla. (**h**) Superior repositioning

of maxilla. (**i**) Fixation of maxilla with mini plates and screws. (**j**) Open bite on right side of occlusion because of asymmetric superior repositioning. (**k**) Unilateral sagittal split osteotomy of mandible split and fxed with mini plates and screws. (**l**) New Occlusion achieved. (**m**) Closure of wound done

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**Fig. 69.31** (continued)

gingiva is elevated to expose the alveolus. The midline osteotomy is carried out using a sagittal or piezo saw from the piriform rim of the nose, to the alveolus. The mid-palatal suture osteotomy is completed with chisels. The zygomaticomaxillary buttresses clearance is confrmed intraoperatively by activating the palatal appliance (Fig. 69.34a–c). The remainder of the procedure is according to Le Fort 1 single piece osteotomy [70].

#### **Salient Features of SARPE**

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**Fig. 69.32** (**a**, **b**) (**a1, a2, a3**) Pre-surgical pictures of patient with cant; (**b1, b2, b3**) postoperative asymmetric superior repositioning of maxilla and unilateral sagittal split osteotomy of the mandible to close the open bite created (Also see Figs. 69.30, 69.31 and 69.40)

7 mm, a SARPE procedure is preferred as it would offer more stability.

#### 1536

**Fig. 69.33** It is important to continue the saw or cut with a fssure bur through the inferior part of the zygomatic arch and extend it inferiorly and posteriorly to enable the important back cut to the pterygoid plates. This reduces the possibility of unwanted propagation of fractures to the cranial base

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**Fig. 69.34** (**a**) Maxilla down-fracture, paramedial osteotomy, palatal expansion device in situ, and checking for the horizontal segmental movement. (**b**) Midline palatal osteotomy, device for palatal expansion, (**c**) Tooth- borne Haas & Hyrax Appliance

**Fig. 69.34** (continued)

#### **69.7 Sequence of Bimaxillary Surgery**  (Fig. 69.31a–m)

A single surgical procedure can be employed to correct skeletal deformities of the mandible and the maxilla as well. The surgeon generally determines the preferred sequence. The authors personal preference is provided below.

1. The mandibular bony cuts are usually performed frst, without splitting the mandible. This is followed by completion of the maxillary osteotomy, repositioning and fxation. In the past, fxation was only by trans-osseous wiring. Hence, when the mandible was performed frst, its position was arbitrary as it incorporated the mobile proximal fragment (due to the TMJ) based on which the fnal maxillary position was determined. To avoid this the maxilla was completed frst.

The authors personal preference has been detailed above. Alternatively, mandibular splitting may be performed frst, and an intermediate splint may be used to to fx the mandible to the unoperated maxilla. The maxilla may then be stabilized to the operated and repositioned mandible. However, it must be noted that stabilization and fxation of the mandible are more challenging than for the maxilla. Rigid fxation may be more challenging if an improper or misdirected split occurs. The procedure may even need to be aborted altogether. However, by stabilizing the maxilla frst, the mandible can use appropriately positioned maxilla for stabilization. Therefore, we have always preferred to complete the maxillary surgery before mandibular surgery.

Having listed a general guide above, we reiterate that no dogma should be given regarding the sequence of maxillary or mandibular surgery. Proper planning and preparation will in turn logically dictate the sequence, which must be kept fexible [73].

#### **69.8 Soft Tissue Changes with Le Fort I Osteotomy**

Changes in the jaw position in turn lead to changes in the position of soft tissues such as the lips, cheeks, and nose [74]. The lips may show thinning, reduced vermillion show, and may lack adequate lip support [46]. The nasal tip may be upturned, the alar base width may increase, and the nasolabial angle may widen [75] (Fig. 69.35a–c). Soft tissue swelling

A. Dabir and J. Vahanwala

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**Fig. 69.35** (**a**–**c**) (**a**) reduction of a strip along the caudal septum will shorten the nose; (**b**) reduction involving the nasal tip as shown will increase the nasolabial angle; (**c**) wedge reduction predominantly at the septal base will reduce the nasolabial angle

may take up to a year to resolve, so these changes may not be apparent immediately [76]. In some regions, such as the subnasale, and the lips, greater than 10% change has been documented over 5 years [4]. Nasal changes are quite complex and are therefore unpredictable. Both the structure of the nose (including nasal cartilage connective tissue, anterior nasal spine, and the other nasal cartilages) and the degree of movement of the maxilla play a role in nasal changes. Other patient-related factors, including thickness and morphology of the soft tissue, postoperative healing, age, and ethnicity, can also affect nasal changes, which may either be favorable or unfavorable or benefcial. The nasal width alone increases predictably in Le Fort I osteotomies, and the increase in width depends on the extent of maxillary movement. Adjunctive procedures to limit widening of the nasal width may be performed intraoperatively. These include alar cinch suture and piriform aperture sculpting. Alternatively, the changes may be accepted and later procedures can be performed if necessary. The disadvantage of this is the need for an additional surgical procedure, e.g., alar wedge resection rhinoplasty. The alar cinch suture and V-Y closure (ACVY) is effcient and less invasive in controlling nasolabial changes. Its long-term results need to be evaluated. One study showed that the alar base cinch suture reduced the inter-alar width to its preoperative width following a Le Fort I osteotomy. The suture was stable when evaluated at 12 months and 3 years postoperatively [77]. There have been studies comparing nasal and maxillary vermilion morphology after Lefort osteotomies by simple primary closure, Single VY closure and Double VY closure. The results indicated that better aesthetics are seen in double VY closure cases (See Hackney et al. 1989, Ledezma et al. 2014, in Additional reading provided). However a systematic review in 2014 couldn't reach a conclusion regarding the effcacy of various methods of closure in Lefort Osteotomies.

#### **69.9 Specifc Considerations**

metrical jaw movements (deviations), malocclusion, and aberrant maxillary position.

#### **69.9.1 Adjustment to the Anterior Nasal Spine and Piriform Aperture**

Mommaerts et al. reported that the anterior nasal spine is a signifcant component of nasal tip projection and may be reduced to limit the degree of nasal tip rotation [81]. Betts et al. also stated that changes in the lateral part of the piriform aperture signifcantly affected the soft tissue of the nasal base and nasal tip projection [82].

It is important not to remove too much of the septum as this can produce a retracted columella, which is a potentially unattractive feature.

Osseous recontouring of the nasal crest of the maxilla and/or resection of a portion of the caudal extent of the cartilaginous septum is recommended to keep interference at bay. Placement of a suture through the anterior nasal spine and cartilaginous septum to prevent its displacement upon removal of the nasoendotracheal tube is benefcial.

#### **69.9.2 Efect of Changing the Inclination (Slope) of the Osteotomy Cut**

If the osteotomy cut is made in a parallel direction to the occlusal plane and the maxilla is advanced, the maxillary incisor exposure will increase but the face height will not change. However, if the osteotomy cut starts high posteriorly and slopes downwards toward the piriform aperture, the maxilla will move down the slope as it is advanced, thus increasing the maxillary incisor exposure. The mandible will subsequently rotate in a clockwise direction and the lower anterior face height will increase (Fig. 69.36a, b). The opposite is true for the osteotomy cuts that start low posteriorly and slopes upward toward the piriform aperture (Fig. 69.37a, b).

#### **69.9.3 Impacted Wisdom Teeth**

If an impacted maxillary wisdom tooth is indicated for removal, this is done through the sinus foor. Using a rotary drill with a rosette bur, the bone from the sinus foor, which lies above the impacted tooth, is removed. Next, a tapered fssure bur is used, and the bone just adjacent to the impacted tooth is removed. The impacted wisdom teeth may also be sectioned if necessary

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**Fig. 69.36** (**a**, **b**) Diagram showing effects of the inclination (high to low postero-anteriorly) of the osteotomy cut when advancing the maxilla—(**a**) osteotomy inclination to increase incisor exposure and potentially increase lower face height, (**b**) advancement of maxilla producing increase of lower facial height due to downward ramp effect

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**Fig. 69.37** (**a**, **b**) Diagram showing effects of the inclination (low to high postero-anteriorly) of the osteotomy cut when advancing the maxilla—(**a**) osteotomy inclination to reduce incisor exposure and poten-

to aid in removal; this usually depends on the developmental stage. The tooth is delivered using a dental elevator. Rarely, perforation through the palatal mucosa may occur.

#### **69.9.4 Erupted Wisdom Teeth**

If the maxillary wisdom tooth is completely erupted, this may be extracted prior to down-fracture. This will allow the operator to have a stable "workbench" during extraction. In order to maintain the blood supply to the down-fractured maxilla, the adjacent palatal and labial mucosa must be preserved carefully at the time of extraction.

#### **69.9.5 Considerations of Pre-operative Difculties**

The pre-surgical workup and planning of patients who require corrective jaw surgery required detailed analysis of clinical features, study models, and plane radiographs. Radiographic analysis includes comprehensive assessment of lateral cephalograms, postero-anterior cephalograms, and orthopantomograms. The need for multiple individual planar views has been replaced by the advent of cone beam technology.

#### **69.9.6 Considerations of Operative Difculties**

Horizontal osteotomy of the maxilla should result in a clean pterygomaxillary separation to subsequently allow for tially reduce lower face height, (**b**) advancement of maxilla producing reduction of lower facial height due to upward ramp effect

down-fracture and mobilization. At this step, the pterygoid plates should ideally remain intact and attached to the skull base. However, in some exceptional cases, such as patients with cleft maxilla, the pterygoid plates are unusually thick and well buttressed. On the other hand, some patients have thin and almost translucent pterygoid plates [83]. Pterygomaxillary synostosis (fusion) may be seen in up to 12% of all patients [21].

If the pterygoid plates fracture at a lower level, this may cause diffculties in down-fracture and mobilization, because of the attachment of the pterygoid musculature. On the other hand, if the plates fracture at a higher level, the fracture may propagate into and along the skull base, which can potentially cause neuro-ophthalmic complications.

On postoperative CT scans, the incidence of pterygoid plate fracture after a Le Fort I osteotomy was found to range from 58 to 75% [84, 85]. However, despite this high incidence, the incidence of fractures propagating to the skull base/orbit is low [83].

Lanigan et al. carried out a study on unfxed fresh cadavers and found that 26% of cases were "diffcult downfracture." They stated that this was probably due to the presence of "thick bony maxillary walls" [83].

These authors stated that if a diffcult down-fracture was encountered after a routine Le Fort I osteotomy, then the posterior walls of the maxilla must be sectioned completely using an osteotome. Alternatively, sectioning through the tuberosity could be performed, using a micro-oscillating saw or straight osteotome, as this would avoid the thick posterior walls and aid in pterygomaxillary separation. However, these authors have stated that it would not be possible to totally prevent untoward fractures that could occur during pterygomaxillary disjunction and down-fracture. We emphasize that thorough CBCT imaging should be undertaken preoperatively, as this would familiarize the surgeon with the maxillary morphology.

The following maneuvers may help if the surgeon fnds diffculty in down-fracture following osteotomy and disjunction:

O'Regan and Bharadwaj stated that an osteotome or saw must never be used blindly in these situations [86].

#### **69.9.7 Proper Positioning**

**Fig. 69.38** (**a**–**c**) (**a**) The proper method for condylar seating at the time of maxillary positioning prior to fxation. Posterior prematurities are best appreciated with this method. (**b**) Pressure on the chin to push the anterior aspect of the maxillary osteotomy together may rotate the condyles inferiorly and posteriorly while maxillary fxation is applied. (**c**) Upon release of intermaxillary fxation, the condyles may return to the fosse, and an open bite may appear. Unfortunately, this open bite may not appear immediately, especially if postoperative elastics are used to "guide" the occlusion

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surgical move. This is much less likely with advancement than it is with other moves such as impaction.

• It is often easiest to adapt the plates for fxation with Le Fort osteotomy and initially secure them only to the inferior fragment. Once all the plates are properly bent and secured to the inferior fragment, the maxillomandibular complex and condyles can be positioned with great care, and the shape and bending of the plates critically evaluated and secured to the superior fragment in succession, while the maxillomandibular complex is held in position.

#### **69.9.8 Nutritional Support**

Orthognathic surgery throws up many physiological challenges. These include postoperative facial swelling and catabolism which increase the nitrogen requirements. If these are not met, wound healing may be compromised. A diet fortifed with macro- and micronutrients and adequate hydration is therefore essential [87].

Mandibular movements may be restricted in the postoperative period, owing to facial swelling and pain. Meeting the daily nutritional needs and hydration requirements (Table 69.1) may therefore be diffcult. Studies have shown that in 6 weeks following surgery, patients can lose between 3.1 and 6.8 kg of weight [88].

It is important to adapt the diet to suit these needs, to promote wound healing, and to minimize postoperative complications. Another important factor in patient recovery is the patient's mood. Adequate nutrition and hydration will serve to improve the patient's mood, thereby diminishing postoperative irritability or depression [89]. Dietician assessment of nutritional status is essential to ensure that the above goals are achieved.

The modifcation of the diet is a sequential process. This aims at reducing the masticatory forces on the underlying healing bone, which in turn optimizes the conditions for healing.

**Table 69.1** Recommended postoperative nutrition requirements for patients above 16 years, undergoing orthognathic surgery [87]

chewing, and foods may be mashed. The high-energyhigh-protein diet must be continued.

3. After the second week, light chewing may be done, and a soft diet is recommended. The jaw muscles may fatigue easily at frst, but gradually the muscles adapt to the new position. The soft diet is continued for two months, after which regular diet may be resumed [87, 90–98].

#### **69.9.9 Complications**

Rigid fxation with plates provides the initial stability until bone has united. Bone frst unites in the pterygoid region [99]. The most stable maxillary movement is superior repositioning, followed by advancement, and the least stable is inferior repositioning. However, the studies looking at the inferior positioning of the maxilla have been based on the need for bone grafting. Studies have reported relapse rates for maxillary superior repositioning of the maxilla ranges from a mean of 0–18% for the anterior maxilla and 6–7% for the posterior maxilla. Relapse rates for maxillary advancement range from 5 to 15%. As with most orthognathic surgery, relapse is greater with increase in the maxillary advancement. With inferior maxillary repositioning (using bone grafts), there may be 28% anterior relapse and up to 70% posterior relapse [100]. Nonunion is rare and probably associated with failure of the initial plate fxation and poor bony contact. If this persists for greater than 6 months, further surgery with rigid fxation and autogenous bone grafting is recommended [101]. Maxillary advancement and posterior and superior movements are shown to be stable, whereas inferior and transverse movements are unstable [99–110]. The use of autogenous bone grafts and/or hydroxyapatite has been proposed to improve the stability of inferior repositioning of the maxilla [101, 111–117].

### **69.10 Recent Advances** (Refer Figs. 66.21 and 78.51)

#### **69.11 Conclusion**

The development of modern maxillary orthognathic surgical procedures had diverse historical origins and contributions. With advancement in technique and the introduction of safe hypotensive anesthesia, the Le Fort I osteotomy has been increasingly utilized over the last four decades. Over the years, various modifcations of the osteotomies, ORIF methods and bone grafting to the mobilized maxilla, have continued to evolve and progress. The Le Fort I osteotomy of the maxilla is one of the core procedures in orthognathic surgery for the management of facial skeletal deformities. The surgery, often used in conjunction with the bilateral sagittal split osteotomy, is used to correct functional and cosmetic irregularities in all three planes of space and can be utilized in the treatment of a wide range of malocclusions. Traditionally, the surgery has been known for its low technical diffculty and dependable results. Changes in the soft tissue of the nose, lips, and cheeks due to this surgical procedure need due consideration.

The risk of complications is higher in patients with segmental Le Fort 1 osteotomies or anterior movements greater than 9 mm. Efforts to minimize maxillary movement (e.g., with two-jaw surgery) are recommended to reduce complications. An emphasis should be placed on proper pre-surgical orthodontics and solid pre-surgical planning to ensure predictable and stable results. It is also imperative to plan and provide for optimal nutrition as Orthognathic surgery throws up many physiological challenges that may compromise the nutritional status including catabolism, postoperative facial swelling, and increased nitrogen requirements to promote wound healing. The premise of maxillary orthognathic surgery is therefore a multidimensional approach through planning, execution, and postoperative management.

Disclosure Authors have no fnancial conficts to disclose. Authors have written consent and reconfrmation from the patients for the use of clinical pictures.

#### **69.12 Case Scenarios**

**Case Scenario 1** (Figs. 69.28, 69.29 and 69.39a–h)

#### **(A) Chief Complaints**

Gummy smile Long face Defcient chin Protruding upper front teeth

#### **(B) Postoperative Result**

Competent lips Normal chin projection Balanced face

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 69.39** (**a**–**h**) Vertical maxillary excess with mandibular defciency. Treatment: Le fort I with superior repositioning of maxilla; bilateral sagittal split ramus osteotomy advancement; advancement genioplasty. (**a**) Pre-operative profle picture; (**b**) pre-operative frontal view; (**c**) pre-operative lateral cephalogram. (**d**) Pre-operative OPG; (**e**) postoperative lateral profle; (**f**) postoperative frontal view; (**g**) postoperative lateral cephalogram; (**h**) postoperative OPG showing the implants and the osteotomy cuts in mandible. (Also see Fig. 69.28)

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 69.40** (**a**–**i**) Facial asymmetry with maxillary occlusal cant, deviation of chin (surgery for left TMJ ankylosis and genioplasty done previously elsewhere). Treatment: Le fort I osteotomy for correction of maxillary occlusal cant; right unilateral sagittal split ramus osteotomy to close the open bite. (**a**) Pre-operative profle picture; (**b**) pre-opera-

tive frontal view; (**c**) pre-operative PA skull; (**d**) pre-operative OPG; (**e**) pre-operative lateral cephalogram; (**f**) postoperative profle picture; (**g**) postoperative frontal view; (**h**) postoperative PA skull; (**i**) Post-operative OPG (Also see Figs. 69.30, 69.31 and 69.32)

#### **Surgical Procedure**

Le fort I osteotomy for superior repositioning of maxilla

Bilateral Sagittal Split Ramus osteotomy for advancement of mandible

Advancement genioplasty Later rhinoplasty was done.

#### **Case Scenario 2** (Figs. 69.30, 69.31, 69.32, and 69.40a–i)

#### **Chief Complaints**

Facial asymmetry

Deviation of chin to left

Incisal/occlusion cant (Fig. 69.30)

Facial asymmetry was secondary to ankylosis of left TMJ. Left side treated with costochondral graft when patient was younger.

#### **Pre-operative Findings**

Occlusal cant

Asymmetry of face

The patient presented with occlusal canting visible at the anterior region. This needed to be addressed as it is clinically evident and may affect visual cosmesis.

Judge the incisal cant by drawing an imaginary interpupillary line and its inclination with incisal cant represented by the metal scale held in incisors

#### **Surgical Plan** (Figs. 69.31 and 69.32)

Le Fort I osteotomy for superior repositioning of maxilla on right side by 5 mm

Sagittal split osteotomy on right side of mandible to match mandible to maxilla

#### **References**

and Maxillofacial Surgeons. 2020 Sep. https://doi.org/10.1016/j. joms.2020.09.005.

122. Heufelder M, Wilde F, Pietzka S, et al. Clinical accuracy of waferless maxillary positioning using customized surgical guides and patient specifc osteosynthesis in bimaxillary orthognathic surgery. Journal of Cranio-maxillo-facial Surgery: Offcial Publication of the European Association for Craniomaxillo-facial Surgery. 2017;45(9):1578–85.

#### **Additional Readings**

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**70**

## **Facial Asymmetry**

Neelam N. Andrade, Paul Mathai, and Neha Aggarwal

#### **70.1 Introduction**

Physical appearance is of much signifcance to the humans, as the human mind perceives the slightest form of deviation from normal form, function, and symmetry of the body and especially of the face as it is easily discernible [1]. Facial asymmetry could be defned as a clinically perceptible and signifcant difference between the two halves of the face. Every individual has some degree of asymmetry which may provide a uniqueness to the face. However, the magnitude and acceptability of the same depend on the location of the asymmetry and the patient's perception of disproportion. Facial asymmetry may also adversely affect the patient's nutritional and psychosocial development [2].

Any abnormality of the soft or hard tissues can lead to asymmetry. This could be a consequence of a congenital anomaly, a developmental, or an acquired defect. Asymmetry can be progressive in nature, while those acquired due to trauma or ablative surgeries are non-progressive [2, 3]. It is prudent for the clinician to consider the aetiology of the asymmetry, the extent, and its severity in all three dimensions in order to provide an optimal treatment plan. Besides, it is important to take into consideration factors such as growth, timing of treatment, and psychological aspirations of the patients when deciding the treatment plan [3, 4].

The present chapter will discuss the etiopathogenesis and classifcations, clinical considerations, and diagnosis, evaluation, and treatment planning of facial asymmetries. Few interesting case scenarios will also be discussed for a better understanding of clinical presentations and their management.

#### **70.2 Classifcation**

Understanding the etiopathogenesis and classifcation of facial asymmetry allows for accurate diagnosis, optimal treatment planning, and improved surgical outcomes. Facial asymmetries are most commonly classifed according to aetiology or morphology. Other classifcations are based on time of onset, structures involved, and surgical planning outcomes and may even be restricted to the mandible alone. Table 70.1 is a summary of the various classifcation systems available to us today [5–19].

We have identifed three classifcations that are essential for the evaluation and treatment planning of facial asymmetries [Table 70.2 by Cheong et al. (2011) [13], Table 70.3 by Wolford et al. in (2009) [11], Table 70.4 by Wolford et al. (2014) [2, 19–21]].

#### **70.3 Diagnostic Evaluation**

Facial asymmetry is usually the least at the cranial base level and increases toward the lower levels of the face, with the mandible and chin commonly exhibiting the greatest asymmetry. Hence, the cranial base is used as a reference plane for assessing the type and severity of the asymmetry in the middle and lower thirds of the face. Conditions where the cranial base is also involved like syndromic or non-syndromic craniosynostosis, tumors of the cranium, and midface and Tessier's craniofacial clefts cannot be assessed in a routine manner. The presence of orbital dystopia, unequal pupillary heights, and/or unequal ear heights will make the assessment more challenging [2, 20, 22, 23].

Every clinical examination begins with identifying the chief complaint of the patient followed by a detailed physical and medical evaluation of the patient. In order to better understand the facial asymmetry, it is studied in the sagittal, coronal, and vertical dimensions with the cranial base as the reference plane. Common facial planes that represent the

N. N. Andrade (\*) · P. Mathai · N. Aggarwal

Department of OMFS, Nair Hospital Dental College, Mumbai Central, Mumbai, India

<sup>©</sup> The Association of Oral and Maxillofacial Surgeons of India 2021 1549

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_70

**Table 70.1** Summary of the various classifcation systems

**Table 70.2** Major etiological factors of facial asymmetry, according to Cheong et al. (2011) [13]

cranial base are the pupillary plane, the ear plane, and the clinical Frankfort horizontal plane. It is also important to note that patients may hold the head in an abnormal position or use hairstyles and mannerisms to mask the extent of the asymmetry [e.g., a patient with a defcient mandible may tip his head upward in order to improve chin projection]. It is important to identify these compensatory mechanisms during the treatment planning process. Similarly, it can be benefcial to study the lower or middle third individually in comparison with the unaffected upper third [cranial base] by blocking out the part not being studied with an opaque sheet [e.g., card board] [20, 23].

#### **70.3.1 Clinical Evaluation: Frontal, Axial, and Profle**

#### **Frontal View**

The patient's head is positioned such that the interpupillary plane or ear plane [passing through the bottom of the ear lobes or tragi of the ears] is parallel to the foor. The pupillary plane can also be used for assessing bilateral vertical discrepancies by measuring height differences from the plane to the mandibular angles, chin, nose, and commissures (Fig. 70.1). The facial midline is represented by a vertical plane passing through the nasion or glabella, perpendicular to the pupillary plane and ear plane (Fig. 70.2). It allows to compare the degree of left-to-right asymmetry and transverse facial width discrepancies of various facial structures [e.g., orbits, pupils, malar eminences, nose, commissures, and mandibular angles]. In case of some imbalance in the frontonasal region [e.g., past naso-orbito-ethmoidal trauma], other landmarks can also be used as a reference to identify the facial midline, e.g., half the interpupillary or inter-canthal distance, the subnasal point, or the philtrum [20, 22].

**Table 70.4** Wolford's classifcation of condylar hyperplasia [CH] 2014 [2, 19–21]

The patient should be reminded to relax the peri-oral musculature for assessing the tooth to upper lip relation at rest [e.g., patients with vertical maxillary excess will constantly purse their lips to reduce excessive gum and teeth show]. The smile needs to be assessed for the amount of gingival show on either side, tooth to upper lip relation, comparison of dental midline with facial midline and symmetry by comparing parallelism of commissural and pupillary lines. Finally, a tongue blade or thin ruler can be placed between the maxillary and mandibular canines and premolars to assess the presence of a cant in relation to the pupillary plane (Fig. 70.2). Comparing the vertical heights from the pupillary plane to the canine tips on either side can help quantify the cant. An occlusal plane inclination of greater than 4° is said to cause signifcant perceptible asymmetry.

Assessment of midline structures such as nasal bridge, nasal tip, philtrum, and the chin point should also be carried out. Submental [worm's-eye] (Fig. 70.3) and superior [bird'seye] views (Fig. 70.4) are very useful in assessing deviation of the abovementioned structures. We can also assess symmetry

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.1** Various facial planes **A** horizontal plane (interpupillary plane) **B** horizontal plane (inter tragal plane) **C** horizontal plane (plane marked through ear lobes) **D** vertical plane (mid-sagittal plane) ©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.2** Occlusal cant in relation to the pupillary plane and asymmetry marked from medial canthi to the oral commissure

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.3** Submental (worm's-eye) view exhibiting asymmetry in the lower facial third and skeletal midline

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.4** Superior (bird's-eye) view exhibiting midline discrepancy and rotation of the face

and projection of the anterior cranial vault, orbital areas, nose, cheeks, malar eminences, and mandibular body contours.

#### **Profle View**

In order to avoid underestimating the severity of the facial asymmetry due to compensatory head postures, it is essential to position the head so that the clinical Frankfort horizontal plane (a line from the tragus of the ear through the palpable bony infraorbital rim) is parallel to the foor (Fig. 70.5). The patient should also be reminded to relax the peri-oral musculature to better assess the tooth to upper lip relation at rest. Evaluating the left and right sides from the profle view will allow assessment of discrepancies in the antero-posterior and vertical dimensions [e.g., maxilla, mandible, and chin] rather than asymmetry evaluation.

#### **70.3.2 Oral Examination**

Orthodontic study models mounted in centric relation by face-bow transfer onto a semi-adjustable anatomic articulator help in dento-alveolar and occlusal assessment with a further advantage of studying the occlusion from the lingual aspect. The dental arches are evaluated for overdevelopment, underdevelopment, presence of yaw, and asymmetry in the antero-posterior, transverse, and vertical planes. The dental examination should include the presence or absence of missing, deformed, carious, impacted, or ankylosed teeth; dental midline shift; dental crowding or spacing; congenital deformity [e.g., cleft alveolus in a case of cleft lip and palate]; habitual pattern [e.g., tongue thrusting or thumb sucking]; pathology; and size of tongue and trauma (Figs. 70.6, 70.7, and 70.8). These fndings can be incorporated into the treatment planning.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.5** Orientation of FH plane parallel to the foor

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.6** Complete telescoping of the maxilla

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.7** Crowding in both arches along with a reverse overjet

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.8** Non co-incident dental midlines (blue-upper dental mid line, yellow-lower dental midline)

#### **70.3.3 Photographic Examination**

A dedicated photography room where extra-oral and intraoral photographs are taken under standardized settings [e.g., lighting, background, focal length, and distance-to-subject] is ideal. Extra-oral photographs of the frontal [with and without smile, occlusal and mandibular inferior border cant], three-quarter, submental, and superior views are essential for the assessment of facial asymmetry. Intra-oral frontal, lateral, superior [45° to the occlusal plane from above], and inferior [45° to the occlusal plane from below] views with the teeth in occlusion are essential for dento-alveolar assessment [11, 23–26].

#### **70.3.4 Radiographic Examination**

The three primary radiographic examinations performed in the assessment of facial asymmetry are lateral cephalometry, postero-anterior cephalometry, and orthopantomography. They have been described briefy below. As a rule, serial cephalometric assessment every 6 months for a minimum duration of 1 year may be helpful in determining if the asymmetry is static and stable or if it is progressive [24, 25].

1. Lateral Cephalometry:

It is used to assess hard tissue and soft tissue relationships in 2D, i.e., antero-posterior and vertical dimensions. This tool is less commonly used to assess facial asymmetry. The head is placed into a reproducible position within the cephalostat with the help of the nasal bridge indicator and ear roads which closely approximates the clinical Frankfort horizontal plane. The patient keep should also be instructed to keep the jaws in centric relation with the teeth lightly touching and the lips slightly parted or relaxed. The ability of the cephalostat to reproduce the near about the same position every time allows for comparative cephalometric analysis and super-imposition of tracings. Bilateral vertical discrepancies [e.g., increased vertical dimension of the body and ramus-condyle unit of the mandible in unilateral condylar hyperplasia type 2] can usually be assessed in a lateral cephalogram. The right and left sides are presented as two separate nonsuper-imposing lines, and this can be measured as a discrepancy between the two images of the occlusal plane and inferior borders of the mandible (Fig. 70.9).

2. Orthopantomograph [OPG]:

The OPG is an excellent tool to evaluate mandibular asymmetry and dental status. The anatomy of the condyle—ramus unit, body, and inferior border of the mandible is readily discernible. Increase or decrease in dimensions or changes in mandibular morphology can be studied. In cases of unilateral asymmetry, the affected side can be compared to the normal side. The course of the inferior alveolar nerve can also be assessed and is of vital importance if an inferior border osteotomy is being performed [e.g., inferior border osteotomy in cases of unilateral condylar hyperplasia type 2 where the inferior alveolar nerve might be coursing near the lower border of the mandible] (Fig. 70.10). The OPG is also an excellent tool for the screening of maxillofacial pathology that may cause facial asymmetry, e.g., tumors and fbro-osseous lesions.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.9** Lateral cephalogram showing double images of the inferior border of the mandible (blue arrows) along with displaced IAN canal (yellow arrow) in a case of type 2 condylar hyperplasia

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.10** OPG demonstrating the difference in height of the mandibular body (blue arrows), displacement of the IAN canal toward the inferior border (yellow arrows)

#### 3. Postero-antero Cephalometry:

The PA cephalogram allows a comparative study of the symmetry between the structures of the right and left sides. Projections can be obtained in both open mouth position and centric occlusion with head oriented in natural head position to identify the full extent of static and dynamic [functional] asymmetry. The horizontal reference plane is represented by a line passing through the bilateral zygomatico-frontal sutures. The vertical reference plane is a line perpendicular to the horizontal plane passing through crista galli. Transverse and vertical distances of various facial structures are measured by drawing perpendicular lines drawn from the structures in question to the vertical and horizontal reference planes. By comparing the distances measured bilaterally, the type and extent of the underlying asymmetry can be assessed. Additionally, a shift in the dental midlines can be assessed by comparing them to the skeletal midline. The Grummons and Ricketts analyses are commonly used PA cephalometric analyses for the evaluation of facial asymmetry (Fig. 70.11).

4. Computed Tomography/Cone Beam CT with 3D Reconstruction:

The main advantage of the 3D CT scan is that it helps in visualization and treatment planning of complex facial asymmetry in cases like craniosynostosis, Treacher Collins syndrome, hemifacial microsomia (Figs. 78.4, 78.5 and 78.6), TMJ ankylosis, and unilateral condylar hyperplasia (Fig. 70.12a, b). Unlike cephalometric and panoramic radiographs, there is no superimposition of structures, the absolute position of anatomical landmarks can be defned, and viewing is possible from any angle. It is also an excellent tool for patient education. The CT scan data can be used for fabrication of stereolithographic

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.11** Grummons and Ricketts analysis using PA Cephalogram for evaluating the facial asymmetry. Horizontal reference plane (red); vertical reference plane (yellow); ramal height (blue); intercuspid width (green); intermolar width (purple). Refer to additional reading

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.12** (**a**, **b**) 3DCT face analysis for assessing the facial asymmetry. Various parameters include, Arbitrary horizontal reference plane assuming orbits are normal (black); FH plane (purple); mandibular height [canine to mandibular plane (orange)]; maxillary height (frst

molar to FH) (red); ramal length (Co superior to Go inferior) (green); occlusal plane (yellow); lateral ramal inclination (Co superior to Go posterior to FH) (brown); midsagittal plane (light blue)

medical models which help make surgical planning even easier. The disadvantage of the CT scan is the exposure to a high radiation dose; with the introduction of the CBCT, the amount of radiation exposure has been greatly reduced. 3D reconstruction, stereolithographic model printing and integration with 3D stereo photogrammetry data allows for treatment planning, treatment simulation, and assessment customized according to the patient [e.g., Dolphin 3D, IPS by KLS Martin]. Lastly, both CT and CBCT provide valuable information regarding the hard tissue status of the TMJ and aid in the diagnosis of reactive [infammatory] arthritis of the TMJ, osteoarthritis of the TMJ, idiopathic condylar resorption, avascular necrosis, and degenerative remodeling of hard tissues of the TMJ in dentofacial asymmetries [24, 25].

5. Magnetic Resonance Imaging:

MRI is primarily used to study the soft tissues of the TMJ [e.g., disc, capsule, ligaments] and combined with the CT/CBCT scan data is able to accurately diagnose reactive [infammatory arthritis] of the TMJ, internal derangements, condylar resorption, and degenerative remodeling of soft tissue of the TMJ in dentofacial asymmetries (Fig. 70.13a, b) [e.g., thinning and displacement of the disc of the contralateral unaffected TMJ in cases of unilateral condylar hyperplasia] [24, 25].

#### **70.3.5 Stereophotogrammetry**

It is the construction of a three-dimensional model based on the positions of recognizable points or landmarks in several different photographs. It utilizes two or more cameras confgured to capture a pair of stereo images of the surface of patient's face which are then used to generate a 3D image of the face by triangulation performed through sophisticated stereo algorithms. The technique is minimally invasive and has an expanded coverage of close to 360° of the structure being studied with quick capture speeds (often under 1 second). These advantages make it is particularly useful when working with young children [with craniofacial deformities] for whom quantifcation of facial features can be challenging [25, 26]. The ability to store images for subsequent use, accurate reproduction of the surface geometry of the face, and ability to map realistic color and texture data onto the recorded geometric shape make this technique the preferred facial surface imaging modality over older conventional imaging modalities like laser scanning [26].

#### **70.3.6 Stereolithographic [SLA] Models**

Medical modelling involves frst acquiring a CT, CBCT, or MRI. This data consists of a series of cross-sectional images of the region being studied. The selected part is now created in a layer-by-layer fashion using photopolymerization ultimately forming a three-dimensional solid. The use of such models in maxillofacial surgery has signifcantly improved predictability of clinical outcomes in facial asymmetry cases when compared to similar treatments without its use. The models facilitate direct visualization of complex 3D facial asymmetry, decrease operating time due to better treatment planning, and can also be used as an educational tool for patients (Fig. 70.14) [27].

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.13** (**a**, **b**) MRI of TMJ showing anteromedial disc displacement (yellow arrows)

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 70.14** Facial asymmetry demonstrated on STL model involving both the midface and mandible with hyperplasia involving the right side

#### **70.3.7 Virtual Surgical Planning [VSP]/ Computer-Aided Surgical Simulation [CASS]**

VSP/CASS involves four key stages demonstrated in Box 70.1.

Figure 70.15 shows the sequence involved in VSP/ CASS. The advantages are an increased dental relationship accuracy, reduced OR time, increased patient satisfaction, and decreased costs. Simulating surgery preoperatively allows measurements to the 1/100th of a millimeter, and when combined with 3D-printed splints and customized prebent plates, the reconstructive and aesthetic outcome is supe-

#### **Box 70.1 Four key stages in virtual surgical planning**

**Fig. 70.15** Flow chart outlining the steps involved in virtual surgical planning has been reproduced after permission from the article "Farrell BB, Franco PB, Tucker MR. Virtual surgical planning in orthognathic surgery. Oral Maxillofac Surg Clin North Am. 2014; 26(4):459–73" [28]

rior to traditional 2-dimensional (2D) modelling and cephalometric tracing [28].

#### **70.3.8 TMJ Examination**

TMJs must be healthy for predictable orthognathic surgery outcomes. The TMJ must be assessed before and after orthognathic surgery for joint noises (clicking and popping), localized tenderness, radiating facial [e.g., headaches] and neck pain, and limitation of mouth opening and jaw locking. The literature reports a higher incidence of TMD in patients with retrognathic mandibles and in those with steep occlusal planes [29, 30].

There is no conclusive evidence regarding the effect of orthognathic surgery on TMD with opinions split between improvement, no change, or worsening of signs and symptoms. However, high-angle, class II patients with pre-existing TMD undergoing counterclockwise rotation or large mandibular advancement procedures are known to experience worsening of symptoms. Figure 70.16 is the Boston University Protocol for the management of facial asymmetry requiring orthognathic surgery with pre-existing TMD [29].

#### **70.3.9 Nuclear Medicine Imaging Modalities (Scintigraphy)**

A bone scan is a nuclear imaging test that involves injecting a small amount radiotracer that into the bloodstream. The radiotracer travels through the area being examined and gives off radiation in the form of gamma rays which are detected by a special gamma camera and a computer to create images of your bones. Thus, skeletal scintigraphy offers the potential to identify disease in its earliest stages as it is able to identify any abnormal increases in metabolic activity [31].

Cisneros frst used bone scintigraphy to study mandibular asymmetry in patients [31]. There are two types of bone scan techniques commonly used: skeletal scintigraphy [subtypes: planar bone scanning and single-photon emission-computed tomography] using technetium-99m methylene diphosphate and positron emission tomography [subtypes: with and without CT, full ring and half ring] using radiolabeled 18F-2 fuoro-2-deoxyglucose [glucose analog].

Planar [regular] scintigraphy is not very accurate as it is only a two-dimensional assessment of three-dimensional anatomy. On the other hand, SPECT [single-photon emission computed tomography] allows three-dimensional assessment as the isotope is dispersed in the subject's body thus allowing spatial localization of the pathology in the mapped body organ.

Dedicated/full-ring PET [as compared to half-ring PET] provides better spatial resolution than a planar bone scanning and SPECT (Refer Fig. 78.13) because of its narrower electronic collimation [full width half maximum (FWHM) central resolution for PET being 6 mm compared with 11 mm

for SPECT] [21, 32, 33]. As the condylar growth plate is thin, PET gives an advantage to identify pathologies like condylar hyperplasia. Important factors to be taken into account when assessing

a bone scan:

	- The growth in type 1 condylar hyperplasia is only slightly faster than the normal condylar growth rate. Therefore, the difference in intensity of radiotracer uptake between a normal and affected condyle is negligible.
	- The cellular growth activity is confned to a narrow band at the normal growth center resulting in low uptake of the radiotracer.
	- Condylar hyperplasia type 1A cases: It is diffcult to differentiate CH type 1A from normal growth as it a bilateral condition with both joints involved.
	- Condylar hyperplasia type 1B cases: As this is a unilateral condition, it is easy to identify clinically. There has to be a difference in activity of at least 10% between the affected side and the normal side for a diagnosis of asymmetric growth activity/unilateral condylar involvement to be made.
	- It is easy to diagnose on the bone scan as it is usually a unilateral condition with a tumorous rate.
	- There is diffuse cellular activity throughout the tumor in the condylar head which makes it easier to diagnose on the bone scan.

#### **70.4 Clinical Considerations**

#### **70.4.1 Occlusal and Orthodontic Considerations**

Asymmetries with congenital and developmental etiology are commonly associated with dental compensations in all three dimensions as growth ensues. Rotations and crowding are

**Fig. 70.16** The fow chart outlines the Boston University Protocol for the management of temporomandibular disorders in patients who present for orthognathic surgery and has been reproduced from the article

"Nadershah M, Mehra P. Orthognathic Surgery in the Presence of Temporomandibular Dysfunction. What Happens Next? Oral Maxillofac Surg Clin North Am. 2015; 27(1):11–26" [29]

seen in hypoplasia cases such as hemifacial microsomia, and spacing and cross bites can be encountered in case of overdevelopment such as condylar hyperplasia. Transverse growth discrepancies also result in different arch shapes and Bolton discrepancy. Also, the extent of maxillary asymmetry should be accounted for, as maxilla tends to be ignored in obvious mandibular asymmetry. Thus, pitch, yaw, and roll need to be adjusted or decompensated keeping the surgical movement in mind [34]. Pre-surgical orthodontic treatment in patients with facial asymmetry must include the following:

(a) The presence of a dental and facial midline mismatch indicates a discrepancy in the yaw of the affected jaw[s]. Midline correction at the time of orthognathic surgery provides the best results.

#### **70.4.2 Growth and Development of the Craniofacial Skeleton**

Importance of understanding growth of the maxillofacial skeleton in an individual presenting with asymmetry cannot be emphasized enough. Almost half of the asymmetries are either due to an underdevelopment or an overdevelopment of the TMJ resulting in a deviated mandible in the vertical or antero-posterior direction or both of the involved side or the contralateral side. If this development takes place in the growing period, the maxilla follows the deviation of the mandible. Interceptive orthodontics can be applied in growing areas to arrest or limit the extent of asymmetry of the maxilla and mandible [35]. However, surgical intervention is generally needed after completion of growth period for the fnal skeletal and dental correction. Surgical treatment performed before growth completion is unpredictable on account of the continual growth that the patient experiences till skeletal maturity and as such is reserved only for those cases suffering from extreme functional, aesthetic, and psychological problems. Additional surgery may be needed to correct the recurrent asymmetry. Thus, timing of surgery relies very much on the growth completion.

Serial cephalometric radiographs, scintigraphy, and SPECT scans are useful to assess growth potential. The absence of activity in the TMJ and other areas helps the surgeon to proceed for corrective orthognathic surgery. The second factor for determining the timing of treatment is the progression of the asymmetry. If the asymmetry is progressive like condylar hyperplasia, it is better to wait or perform high condylectomy to check any further asymmetric growth. On the contrary, non-progressive asymmetries such as hemifacial microsomia, treatment can be initiated in early years [36]. Comparably, early surgery has usually been performed for individuals with marked malformations such as plagiocephaly, cleft lip and palate, and/or severe functional burden (e.g., increased intracranial pressure, severe obstructive sleep apnea, etc.). Lastly, in few cases of acquired asymmetry such as tumor resection, "wait-and-watch" policy needs to be adopted to eliminate chances of recurrence before a defnitive reconstruction can be planned.

### **70.4.3 Role of Functional Orthopedics and Interceptive Orthodontics**

Functional orthopedics play a substantial role in congenital asymmetries, the greatest example being nasoalveolar molding in cleft lip and palate cases to bring the maxillary segments into a more desirable position prior to surgery. Growth modifcation with the use of functional appliances is directed toward eruption of the dentition in a more favorable position and prevents worsening of the skeletal asymmetry exacerbated during growth period. Functional therapy is also aimed at maintaining the condyle in a more anatomical position to allow further growth in a symmetrical pattern. Studies have shown that an asymmetric lateral force during the growth period results in growth modifcation by infuencing the morphology of the mandibular bone and the overlying masseter muscle. Occlusal splints can be fabricated to allow for mandibular shifts toward midline, and open bite can be created to eliminate canting. This is especially helpful in hemifacial microsomia and TMJ ankylosis cases. Patient compliance is a prerequisite in functional therapy cases. Also, keeping in view the growth potential, longterm follow-up is always warranted.

#### **70.4.4 Role of TMJ and Considerations for Treatment**

TMJ is the driving force in the development of an asymmetry. Although the role of condylar cartilage has been proved to be secondary in mandibular growth and development, any pathological change leading to under- or overdevelopment can cause severe progressive asymmetry. As mentioned, TMJ-related asymmetries can be categorized as underdevelopment or overdevelopment of the condyle and in some cases both. Pseudo-asymmetry occurs due to lateral shifts on account of dental pre-maturities. Kaban and Pruzanksy have also graded hemifacial microsomia (Refer Chap. 78) based on the anatomy of the ramus condyle unit [RCU] and the glenoid fossa which make up the TMJ [36, 37]. Management of the TMJ pathology should be performed initially following which any skeletal correction should be attempted. Failure to do so has led to relapse due to the unpredictability of TMJ behavior and growth. Clinical and diagnostic imaging should be performed prior to any asymmetry correction to assess the status of TMJ. CT scans are a must for assessment in all three axes, as TMJ tumors like osteochondroma may not be discernible on 2D imaging. High or low condylectomy, ankylosis release, and RCU reconstruction should be done prior or simultaneously with orthognathic surgery. Distraction osteogenesis has also been used for neo-condyle formation. Alloplastic reconstruction of the TMJ is the most recent advancement with stable long-term results. The rationale for TMJ reconstruction is to provide a functional stable and reproducible movement which is harmonious with the stomatognathic system. Asymmetrical patients have also been found to have a higher incidence of condylar morphological changes and temporomandibular disorders on the affected side. Over time, due to the imbalance of masticatory loads and poor jaw function, the TMJ of the unaffected side also displays similar pathological changes [38].

#### **70.5 Treatment Planning**

Following issues need to be considered before planning orthognathic surgery (Box 70.2):

#### **Box 70.2 Issues that need to be considered before planning orthognathic surgery**

#### **70.5.1 Single Jaw Versus Bi-Jaw Surgery**

Facial asymmetries are rarely corrected by single jaw surgery. When the amount of discrepancy is excessive, it is best treated by dividing the overjet as well as the cant between the two jaws to achieve optimal results. During growth in congenital and developmental cases, maxilla follows and is equally involved as the mandible. Thus, it is prudent to do a bi-jaw surgery. Also, in cleft maxillary hypoplasia cases, differential maxillary advancement with simultaneous setback is the treatment of choice. We have presented a case where simultaneous maxillary distraction was done with mandibular setback. Owing to the presence of a cleft, maxilla has severely deviated midline with an extreme reverse overjet. In such cases, maxillary distraction allows slowly advancing the maxilla and simultaneously correcting the midline by distracting more on the defcient side [39] (Fig. 70.17a–c). Segmental osteotomies or differential surgically assisted rapid palatal expansion (SARPE) might also be needed in some cases to correct transverse asymmetry (Fig. 70.18a–c). Additionally, bone contouring of the mandible and zygoma may be needed to reduce the hyperostotic bone to achieve a harmonious facial contour. This is true in case of hemifacial hypertrophy and hemi mandibular hyperplasia. Similarly, additional augmentation of paranasal areas, malar prominence, and angle of mandible augmentation are frequently indicated in hypoplasia cases.

#### **70.5.2 Mandible First Versus Maxilla First Approach**

Either of the surgical sequences can produce similar outcomes when properly planned and executed in the vast majority of bimaxillary cases. Mandible frst approach is specially mentioned here as it is important in Class 3 asymmetries. Firstly, in cases where maxilla may be hypoplastic, especially in the syndromic cases of mandibular hyperplasia, rigid fxation of maxilla and down-grafting may not give stable results. Thus mandible should be fxed frst, then maxilla. Secondly, because of differential load on the TMJ, CO-CR discrepancy exists, and it is diffcult to achieve a stable centric. In such cases fxing the mandible frst is benefcial [40]. Lastly, Class 3 asymmetries are associated with concomitant TMJ pathologies, hence TMJ surgeries such as high condylectomy may be needed to be performed simultaneously, in such cases, and mandible frst approach is generally the preferred choice.

#### **70.5.3 Surgery First Approach** (Refer Chap. 67)

The surgery frst approach [SFA] came about as there was a need for immediate aesthetic improvement with shortening of the overall duration of treatment. However, it should be known that not all cases fulfl the criteria for SFA [e.g., fat curve of Spee and minimal crowding and rotations]. The total treatment duration can be shorter than the conventional three-staged surgical orthodontic treatment owing to the lack of need of pre-operative orthodontics and the subsequent post-surgical "regional acceleratory phenomenon." However, reliability of SFA is still questionable, especially in more complex dentofacial deformities, like facial asymmetry.

Park et al. reported no signifcant differences in postoperative stability between SFA and OFA after bimaxillary surgery in skeletal class III malocclusion patients [41]. In SFA, vertical dimension in surgical occlusion can increase due to occlusal interference and lead to postoperative counter clockwise rotation of the mandible as occlusal settling progresses during the postoperative orthodontic period. This may contribute toward greater postoperative mandibular forward movement.

#### **70.5.4 Modifcations in Surgical Technique for Asymmetry Cases**

The bilateral sagittal split osteotomy is the commonly used technique in asymmetry cases. It is highly fexible and adaptable in all movements. The three-dimensional anatomy of the mandible must be retained when planning a BSSO. According to Schwartz, three types of surgical move-

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**Fig. 70.17** Case of cleft maxillary hypoplasia who underwent maxillary distraction using internal device. (**a**) Pre-operative profle photo showing retruded midface, (**b**) post-operative profle photo showing good midface fullness, (**c**) post-distraction lateral cephalogram showing distractor in-situ

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**Fig. 70.18** (**a**) View of the maxillary study model. (**b**) Osteotomy cut marked for SARPE. (**c**) Fixation done using miniplate only on left side. This is done to ensure expansion of the only the right side on activation of appliance

**Fig. 70.19** (**a**) When an asymmetric case is viewed along the vertical axis, areas that require immediate bone removal become obvious. Heavy interferences will take place anteriorly on the long side and posteriorly on the short side; (**b**) After the condyle is seated, premature bone contact is noted posteriorly. The area proposed for additional bone

ments can be planned with BSSO in asymmetry cases: in case of a normal overjet and overbite, differential movements will be made that is setback on the long side and advancement on the short side. In Class II asymmetry, in order to achieve symmetrical advancement, there will be a longer advancement on the short side than on the long side and lastly in Class III cases, there will be a larger setback on the long side than on the short side. During surgery, the distal segment rotates from the short side to the long side as the midline is corrected (Fig. 70.19a). Selective bone removal from the area of interferences should be done before the distal segment has been passively repositioned. Bone is removed from the anterior and medial aspects of the proximal segment until there is broad contact along segments. On the short side, frst contact will occur posteriorly [42]. Bone is removed from the medial aspect of the proximal segment posteriorly (Fig. 70.19b, c). This is done to reduce condylar torque during rigid internal fxation to ensure stability of the movement. Figures 70.20a−d and 70.21a, b show a case of unilateral condylar elongation treated with differential BSSO.

removal is indicated by the dotted line; (**c**) Good bone contact has been achieved. Image Source: Schwartz HC. Effcient surgical management of mandibular asymmetry. J Oral Maxillofac Surg. 2011 Mar;69(3):645– 54. doi: 10.1016/j.joms.2009.03.009. Epub 2010 Oct 8. PubMed PMID: 20934795 [42]

#### **70.5.5 Soft Tissue Interventions**

The asymmetrical growth of soft tissues may lead to residual soft tissue asymmetry even after correction of the underlying bony deformity. Furthermore, some asymmetrical craniofacial regions cannot be corrected by means of conventional surgical techniques. Adjunctive soft tissue procedures [e.g., dermis fat transplant, autologous fat transfer, microvascular adipose free faps] might be indicated to achieve bulk in defcient soft tissue deformities such as Parry Romberg syndrome, TMJ ankylosis, etc. Alloplasts such as Medpore, silicone, nanogels, tissue expander, etc. have also been used with varying degrees of success (Sect. 70.7 "Case Scenarios").

#### **70.5.6 Distraction Osteogenesis** (Also refer Chap. 87)

Distraction osteogenesis is the process of native bone formation via traction of osteotomized segments. On account of distraction histogenesis, simultaneous soft tissue and

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**Fig. 70.20** (**a**–**d**) Clinical and radiographic images showing a case of image showing severe facial asymmetry with unilateral condylar elongation on the right side. (**a**) frontal photo, (**b**) profle photo, (**c, d**) lateral and frontal views on volume rendered 3D CT scan

hard tissue augmentation can be achieved. Adequate amounts of advancements can be achieved without any soft tissue limitations. Various cases have been treated successfully with DO that are presented in this chapter. DO has various advantages over conventional osteotomies in complex facial asymmetries. Pre-arthroplastic distraction in ankylosis-related asymmetries has been reported to have excellent results [43]. This is because simultaneous distraction of skin, muscle, and tissue takes place with bone regeneration. Thus, better esthetics are achieved without any need for additional soft tissue procedures. Distraction is often the only procedure of choice in large advancements, rate of relapse is signifcantly lower, and results are much stable. Figures 70.22a−e, 70.23a, b, 70.24a−d and 70.25a−g show a case of facial asymmetry secondary costochondral graft resorption in a case of TMJ ankylosis, treated with stage one distraction osteogenesis followed by defnitive correction with BSSO.

(Also refer Figs. 78.43, 78.44, 78.45, 78.46, 78.47, 78.48, 78.49, 78.50, 78.51, 78.52, and 78.53 for management of facial asymmetry cases due to Hemifacial microsomia and Traecher Collins syndrome).

**Fig. 70.21** Same patient as in Fig. 70.20 demonstrating corrected facial midline and mandibular prognathism postoperatively (**a**) frontal view, (**b**) profle view

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#### **70.6 Conclusion**

Facial asymmetry is a three-dimensional facial deformity having multiple etiologies. Complete and thorough knowledge of the etiological factors, the progressive nature of the asymmetry plays a crucial role in formulating a treatment plan. Growth and development of the individual and timing of intervention is the single most important factor affecting the stability of results in any form of asymmetry. Severe relapses could occur if the exact cause of asymmetry is overlooked and treatment is attempted before completion of growth [44, 45].

**Acknowledgment** Gratitude and acknowledgments to Dr. Harsh Desai and Dr. Shibani Nerurkar for their sincere efforts in collection of data and editing of the contents.

DisclosureAuthors have no fnancial conficts to disclose.

#### **70.7 Case Scenarios**

#### **Case 1: Condylar Hyperplasia with Concomitant Masseteric Hypertrophy** (Figs. 70.26a, b, c, 70.27a, b, 70. 28a, b and 70. 29a, b)

A 27-year-old female patient reported with a complaint of a progressive facial asymmetry and an appearance of fullness over the left angle of the mandible.

On examination, the patient had a tapered, triangular shape of the face with an obvious facial asymmetry which was evident along with elongation of the right side of the face and fullness over the left angle region (Fig. 70.26a). The mandible revealed bowing on the right side with a mild symphysis kink. TMJ on palpation revealed mild clicking on the right side and otherwise equal movements along with unrestricted mouth opening was noted. On assessing the left angle region, an outward projection was noted due to the underlying hyper functioning of the masseter muscle. On clenching, signifcant enlargement of the involved muscle was seen as compared to the contralateral side (Fig. 70.26b).

Intraoral examination did not reveal any occlusal cant (Fig. 70.26c). There was an absence of cross bite/open bite, on either side, along with a stable occlusal relationship. The dental midlines were coincident with the skeletal midline and with each other too. No other dental abnormalities were evident on examination.

Imaging studies revealed mild degree of defection of the chin and mandible toward the left side (Fig. 70.27a, b). Transverse mandibular asymmetry was reported. The condylar head appeared to be irregularly deformed, while the neck on the right side appeared broader as compared to the left side. The ascending ramus appeared elongated with a rounded gonial angle. The mandibular lower border was bowed downward and positioned lower on the right side as compared to the left side. The distance between the tooth 1566

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**Fig.70.22** (**a**–**e**) Case of facial asymmetry post-TMJ ankylosis treatment, due to resorption of costochondral graft. Note the exposed screw intraorally. Left side of mandibular arch fully telescoped inside the maxilla. (**a**) basal view showing gross asymmetry, (**b**) patient retaining good mouth opening after surgery for anlykosis, (**c**) Antero-posterior skull view showing asymmetry on the left side with screw from earlier costo-chondral graft fxation, (**d**) photograph showing trans-oral exposure of screw and (**e**) malocclusion with midline shift to the right, dental crowding and left sided lingual cross-bite

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**Fig. 70.23** (**a**, **b**) Stage 1 treatment in the same patient as in Fig. 70.22, left side vertical ramus distraction to establish equal ramal height. (**a**) Initial height of ramus prior to beginning distraction, (**b**) vertical lenghtening of ramus after completion of distraction

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**Fig. 70.24** (**a**–**d**) Second stage treatment in same patient as in Fig. 70.22: distractor removal with differential BSSO. (**a**) intra-operative photo from stage 1 surgery, showing osteotomy line for distraction (yellow arrow), (**b**) intra-operative photo during distractor removal demonstrating new bone formation(yellow arrow), (**c, d**) intra-operative photos showing osteotomy cuts for BSSO

roots and mandibular canal was increased with displacement of the latter towards the lower border of the mandible on the right side. The right side vertical ramus appeared relatively increased height as compared to the left. Thickened trabecular pattern was also evident on the right side.

#### **Management**

Following preparation for the administration of GA and a scintigraphy report which did not reveal an active mandibular hyperplastic condyle on the right side, the patient was prepared to be taken up for the procedure of an intraoral inferior border osteotomy. An intraoral vestibular incision was taken from 33 regions up to the external oblique ridge on the right side. Complete degloving was done to expose the inferior border in the anterior, body, and angle region of the mandible on the right side. Care was taken to identify the mental foramen and salvage the nerve. Methylene blue ink was used to mark the osteotomy line extending from the right central incisor posteriorly up to the angle region (Fig. 70.28a). It was correlated with the position of the neu-

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**Fig. 70.25** (**a**–**g**) Pre- and postoperative photographs of the same patient as in Fig. 70.22, showing restoration of symmetry and midline (**a, b**) pre and post-operative frontal photographs showing correction of asymmetery, (**c, d**) pre and post-operative profle photographs demonstrating increased vertical height of ramus, (**e**) pre-treatment intra oral

occlusion demosntrating severe shift in the dental midline with lingual crossbite on the left side, (**f**) orthodontic strap-up for dental and arch alignment, (**g**) post-treatment occlusion showing good dental rehabilitation

rovascular bundle, so as to prevent any damage to the same. The cut was initiated with a fne fssure bur under copious saline irrigation extending from buccal cortical plate to lingual cortical plate. With the help of an osteotome, the anterior cut was completed, and the lower inferior hyperplastic border was removed in one piece (Fig. 70.28b). The raw surface was smoothened with a vulcanite bur, and contouring was done to match the normal left side. The wound was closed in two layers with interrupted sutures using 3-0 vicryl. The surgical site was fushed with 2% povidone iodine solution.

For the masseteric hypertrophy on the left side, Botox [botulinum toxin Type A, Allergan™] powder was reconstituted with normal saline solution, pushed within the vial, and 30 units of it were administered using an insulin syringe and 30 gauge needle within the substance of the muscle, divided equally at three sites in a triangular fashion (Refer Chap. 33 and Fig. 33.10 for details on Botox injection to treat masseteric hypertrophy).

Complete correction of facial asymmetry with left side masseteric hypertrophy and right side condylar hyperplasia features was achieved with this surgical method (Fig. 70.29a, b).

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**Fig. 70.26** (**a**, **b**) Frontal and profle views showing facial asymmetry due to condylar hyperplasia of the right side. (**c**) Occlusal view showing dental cant on account of condylar hyperplasia

#### **Case 2: Parry Romberg Syndrome** (Figs. 70.30a, b, 70.31a, b, 70.32a, b, c, 70.33a–h and 70.34a–f)

An 18-year-old female patient reported with gradual disfgurement and shrinkage of the right side her face since last 8–9 years.

Clinical examination revealed an asymmetry of the face on the right side with a marked atrophy of facial soft tissue (Fig. 70.30a). Signifcant orbital dystopia along with a hypoplastic soft tissues in the right, evident on worm's view (Fig. 70.30b). Clinically, a deformed and hypoplastic upper lip was seen with an increased vermillion show of the lower lip, resulting in a slanting rima oris. The right commissure, right ala of the nose, and the right supraorbital ridge region revealed obvious depression.

Intraoral examination revealed a missing upper right permanent canine along with crowding in the premolar region. Alveolar height in the maxillary right premolar region was reduced which was a pathognomonic sign of Parry Romberg (Fig. 70.31a, b). The occlusion was deranged, with a shift of the dental midline to the right.

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**Fig. 70.27** (**a**) PA mandible showing inferior border bowing on the right side and kink in chin region (yellow arrows) which stops at the midline. (**b**) 3D CT shows mild degree of tilting of chin and mandible toward the left side

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**Fig. 70.28** (**a**, **b**) Inferior border osteotomy to remove the excessive contour below the mental nerve

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**Fig. 70.29** (**a**) Pre- and (**b**) post-op correction in facial asymmetry. Reduction of fullness on left side and centralization of chin

Imaging studies revealed some degree of hypoplasia of mandible, zygoma, and maxilla on the right side. Presence of impacted permanent right maxillary canine was evident. The body-angle ramus, coronoid, and condylar process however appeared normal. Alveolar height was reduced in the right maxillary premolar region (Fig. 70.32a, b, c).

#### **Management**

The patient was prepared for GA administration for correction of facial asymmetry. A camoufage technique was planned wherein multiple Medpore© implants were used to fll up the defcient areas on the right side of her face in the right supraorbital, right maxillary alveolar region in the canine, and premolar areas right parasymphysis region of the body of mandible and right side chin along with autologous lipo transfer to increase the volume of the upper lip. Two separate small incisions were taken in the submandibular region anteriorly and posteriorly keeping the intervening skin and tissues intact. Layerwise dissection was done to reach the angle, body, and the anterior regions of the mandible. Tunnelling was done between the two incisions so as to receive the pre-shaped Medpore© implant, which was inserted from the anterior site and was pushed posteriorly to sit on the body, angle, and a portion of the ramus. The implant was notched in the superior aspect, in the region of the mental nerve to prevent impingement of the same. Four long titanium screws were used to fx the Medpore© implant on the body of the mandible on the right side (Fig. 70.33a). An additional half chin implant was placed to augment the defcient chin on the right side for achieving symmetry and was fxed with 2 long titanium screws (Fig. 70.33b). The incision sites were closed in two layers.

Another lateral eyebrow incision was taken on the right side (Fig. 70.33e). Dissection was done to expose the supraorbital rim. Supraorbital foramen and nerve were identifed. An infra-orbital rim Medpore© implant for the right side was inverted and placed on the right supraorbital region to augment this defcient area. Two long titanium screws were used to stabilize the Medpore© implants.

Intra-orally a vestibular incision was taken in the right premolar and canine region. A full-thickness mucoperiosteal fap was raised. The infra-orbital nerve was identifed and protected. A paranasal Medpore© implant was fxed with 1 long titanium screw to give fullness in this region. The wound was sutured in two layers with 3-0 vicryl.

Periumbilical and medial thigh regions were prepared to harvest fat cells. Manual aspiration of the fat cells was done. Following the simple method of sedimentation, the fat cells were separated from the blood components (Fig. 70.33f). 2 mm incisions were taken on either side of the oral commissure. A large 16 gauge epidural needle attached to 10cc syringe was used to push the fat within the substance of the upper lip from either side (more on right side than on the left) increasing the

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**Fig. 70.30** (**a**) Frontal view—right side reveals marked atrophy in the distribution of all three branches of trigeminal nerve. (**b**) Asymmetry of the inferior border evident on worm's-view involving soft and hard tissue

**Fig. 70.31** (**a, b**) Intraoral examination of the same patient as in Fig. 70.30, reveals reduced alveolar height (blue arrow) in the right premolar region (**a**), as compared to the left side (**b**). Alveolar height reduction is an important clinical fnding in Romberg's disease

**Fig. 70.32** (**a**, **b**) 3D CT of the patient in Fig. 70.30 reveals skeletal defciency of alveolar height on right side (blue arrow), and reduction in vertical height of the ramus and body of the mandible on right side, (**c**) left side shows normal anatomy

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**Fig. 70.33** (**a**) Extra-oral incisions—submandibular incisions made anteriorly and posteriorly. Medpore implant in ramus and body fxed with four titanium screws. (**b**) Additional half chin implant fxed with two titanium screws on right side of chin region. (**c**) Paranasal and alveolar Medpore implant fxed through intra-oral approach with titanium screws. Infraorbital nerve protected. (**d, e**) Use of Medpore implant for right side supra orbital rim. Notch placed superiorly to protect the supraorbital nerve. (**f**) Sedimentation to separate fat cells from blood components.  A stitch on either side of the commissure was taken to prevent escape of fat cells (Fig. 70.33h). Overcorrection was done on table. Postoperatively, good facial symmetry was achieved with fullness at the defcient site using fat and implant (Fig. 70.34a−f).

For further case scenarios on management of facial asymmetry refer Figs. 68.19 and 68.38, in Chap. 68 on mandibular orthognathic procedures and Figs. 69.30, 69.31, 69.32 and 69.40 in Chap. 69 on maxillary orthognathic procedures.

**Fig. 70.34** (**a**–**f**) Comparison of pre and post op results after 4 years. Satisfactory correction in facial asymmetry achieved. Pre (Fig. 70.30a) and post treatment frontal photographs (**a, b**) oblique facial views (**c, d**) and basal views (**e, f**) demonstrating better soft tissue balance and symmetry

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#### **References**

#### **Additional Reading**

Grummons DC, Kappeyne van de Coppello MA. A frontal asymmetry analysis. Journal of Clinical Orthodontics: JCO. 1987;21(7):448–465.

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## **Obstructive Sleep Apnea Syndrome**

Suresh Menon

#### **71.1 Introduction**

Obstructive sleep apnea (OSA) is a condition that affects 2–4% of the adult population. This disease has reached a proportion of increasing importance due to its neurological and cardiological consequences. Abnormal pharyngeal anatomy and altered activity of the upper airway musculature dilator physiology are primarily responsible for the collapse of the pharyngeal walls during sleep.

#### **71.2 Defnition**

OSA is defned by the occurrence of daytime sleepiness, loud snoring, witnessed breathing interruptions, or awakenings due to gasping or choking in the presence of at least fve obstructive respiratory events (apneas, hypopneas, or respiratory effort-related arousals) per hour of sleep [1].

When OSA is accompanied by excessive daytime sleepiness, it is termed Obstructive Sleep Apnea Syndorme.

The common terms that are used in OSA are apnea, hypopnea, apnea hypopnea index (AHI), and respiratory distress index (RDI) [2].

increasing respiratory effort for 10 or more seconds leading to an arousal from sleep but not meeting the criteria of an apnea or hypopnea [3].

#### **71.3 Etiopathogenesis**

The upper airway is a fexible structure consisting of muscle and fat tissue and is usually only passively supported by bones. Therefore, it can be easily infuenced by soft tissue factors like fat deposition in the parapharyngeal structures, edema/infammation of the parapharyngeal region, hypertrophy of adenotonsillar tissues, or enlarged tongue.

The primary actor in the pathophysiology of OSA is the narrow, foppy upper airway. There is increased resistance of the upper airway due to anatomic factors that creates a negative airway pressure. This results in impaired function of airway-dilating muscles, thus increasing collapsibility. During sleep, the loss of skeletal muscle tone narrows the upper airway, making it foppier, especially during rapid eye movement (REM) sleep when muscle relaxation is intense. This results in two signifcant actions:

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S. Menon (\*)

Department of Oral and Maxillofacial Surgery, Vydehi Institute of Dental Sciences and Research Centre, Bangalore, India

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_71

Additional factors that can increase the severity of upper airway resistance during sleep are mouth opening or a supine posture which allows the gravitational forces to push the tongue and soft palate back. Upper airway resistance can occur anywhere from the nasopharynx to the hypopharynx but primarily involves the oropharynx (Fig. 71.1).

#### **71.4 Risk Factors for OSA**

#### **71.4.1 Age**

The disease prevalence increases steadily with age and reaches a stable level after the age of 60 years. The probable explanations for the age-related increase in prevalence include increased fat deposition in the parapharyngeal area, soft palate lengthening, etc.

#### **71.4.2 Excess Body Weight**

Body weight is an important risk factor for OSA, and studies have endorsed the positive effects of dieting and surgical weight loss on reducing OSA. Body weight increase can affect normal upper airway mechanics during sleep through:

**Fig. 71.1** Areas causing OSA

#### **71.4.3 Gender**

It is an established fact that men are more vulnerable than women toward developing OSA. The differences exist not only in prevalence but also in polysomnographic characteristics of sleep and breathing patterns. Women were seen to have a lower AHI in non-rapid eye movement (non-REM) sleep. Disordered breathing events in women have a shorter duration and are associated with less oxyhemoglobin desaturation than in men.

#### **71.4.4 Craniofacial Anatomy**

The mechanical properties of the upper airway and the tendency to collapse during sleep can be infuenced by both hard and soft tissues in the region. Findings in the craniofacial region like large tongue or soft palate, reduced mandibular size, or tonsillar hypertrophy in addition to inferiorly placed hyoid, maxillary, and mandibular retropositioning can narrow upper airway dimensions and leading to episodes of apneas and hypopneas during sleep.

#### **71.4.5 Familial and Genetic Predisposition**

Inheritance and familial factors also play a major role in OSA. First-degree relatives of OSA patients seem to be at risk more likely than others. The familial susceptibility tends to increase directly with the number of affected relatives.

Heredity and genetic factors also have been found to have a role in determining the volume of the lateral parapharyngeal

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walls, tongue, and total soft tissue structures. A detailed family history can help in identifying those that have the disorder but remain undiagnosed.

#### **71.4.6 Smoking and Alcohol Consumption**

Cigarette smoking and alcohol are also possible risk factors for obstructive sleep apnea. Airway infammation can occur due to cigarette smoke that could modify the properties of upper airway and increase its collapsibility during sleep. Alcohol consumption before sleep increases upper airway collapsibility and the precipitate apneic and hypopneic episodes during sleep. Another effect of alcohol is to inhibit respiratory motor output to the upper airway, causing hypotonia of the oropharyngeal muscles.

#### **71.4.7 Medical Comorbidity**

There is enough evidence to suggest that OSA can be a factor in the development of hypertension, coronary artery disease, congestive heart failure, and stroke [4].

OSA is also associated with diabetes mellitus, Therefore, diagnosing the condition and intervening early could directly or indirectly enhance glycemic control [5]. The role of positive airway pressure (PAP) therapy could result in reduced day time fatigue, better physical activity, resulting in improved metabolic control.

#### **71.5 Clinical Sequelae [6]**

#### **71.5.1 Endocrine and Metabolic Efects**

The central effects of sleep fragmentation and hypoxemia have been seen to induce a reversible neuroendocrine defect in growth hormone and testosterone secretion. This may explain impaired growth seen in children with upper airway obstruction which seems to get better after adenotonsillectomy.

#### **71.5.2 Neuropsychological and Social Consequences**

The classic feature of OSA prevalent as excessive daytime sleepiness may lead to both impaired work performance and driving. OSA patients seem to perform poorly on psychometric tests, and improvement has been seen after nasal CPAP therapy.

#### **71.5.3 Cardiovascular Sequelae**

There are two serious consequences of OSA involving the cardiovascular system. Initially acute cardiovascular changes occur during an apnea. This is followed by more chronic cardiovascular conditions like hypertension, myocardial infarction, stroke, and death.

#### **71.6 Epidemiology [7, 8]**

OSA has no specifc age predilections, but a study by Young et al. estimated the prevalence in middle age to be 4% for men and 2% for women. Their study estimated that 1 of every 5 adults has at least mild OSA and 1 of every 15 has at least moderate OSA.

#### **71.7 Diagnosis [1]**

A detailed study of clinical signs and symptoms established during a comprehensive sleep evaluation and fndings identifed by sleep testing lead to the diagnosis of OSA.

#### **71.7.1 History and Physical Examination**

The diagnosis of OSA begins with a sleep history in one of three settings:

Of the available, the Epworth sleepiness scale (ESS) (Table 71.1) is a popular subjective-based self-assessment of sleepiness that determines the degrees of sleepiness [9]. When scores are greater than 10, further investigations are recommended. However as about 10% of the population have a score of 11 or more, this score should be complemented by a narrative confrmation of intrusive somnolence.

#### **71.7.2 Polysomnography (PSG)**

This is an overnight sleep study monitored by a sleep technologist and is considered the "gold standard" in sleep medicine (Fig. 71.2). The physiologic parameters measured during PSG include simultaneous monitoring of

#### **Table 71.1** Epworth sleepiness scale

brain wave activity continuously, eye movements, muscle activity of the legs and mandible, body position, heart rate and rhythm, blood pressure, snoring, and respiratory activity including breathing patterns and oxygen saturation. A detailed analysis of these can reveal apneic, hypopneic activities, etc.

Presence of obesity or signs of upper airway narrowing should also be documented.

#### **Patients at High Risk for OSA and Who all should be evaluated for OSA Symptoms [1]**

#### **OSA Symptoms That Should Be Evaluated During a Comprehensive Sleep Evaluation**

#### **71.7.3 Imaging Aids**

#### **<IP_ADDRESS> Cephalometrics**

There is a plethora of imaging aids to help diagnose and plan the management of OSA. Cephalometrics has been the oldest imaging modality in the diagnosis of OSA. However, its role in quantifcation of the pharyngeal volume is controversial as the image that is two-dimensional is used to evaluate a three-dimensional structure [3].

It is a known fact that the lateral pharyngeal wall collapse has a bigger infuence on severe sleep apnea than retropalatal and retrolingual collapse as studied with dynamic MRI, and this would not appear evident on a lateral cephalogram [10]. Another shortcoming of lateral cephalograms is that they are taken with the patient upright and awake and therefore do not characterize the asleep or supine airway.

Cephalometric images however have other advantages that can be used to predict OSA. It can be used to measure the upper airway length (UAL) (Fig. 71.3). UAL is signifcantly longer in OSA patients due to the relation between UAL and airfow resistance. Since the part of the airway is primarily composed of the soft tissues compared to the more rigid, cartilaginous, subglottic airway, this region may predispose to collapse. Studies have proved that male patients with UAL ≥ 72 mm have an eightfold increase in the probability of OSA while females with UAL ≥ 62 mm have a fvefold increase in OSA probability [11].

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.2** Polysomnography leads and parameters. *EEG* Electroencephalogram, *EOG* Electrooculography, *EMG* Electromyography, *ECG* Electrocardiography

Cephalometrics can also be used to predict the success in multilevel phase I therapy for patients. Skeletal class II patients with a more retrognathic mandible are poor responders. Other patients who could be poor responders include those with hyperdivergent vertical pattern with a larger mandibular plane angle, longer lower facial height, and steeper occlusal plane [9].

#### **<IP_ADDRESS> Dynamic Upper Airway Imaging [12]**

Dynamically assessment of the level of upper airway obstruction in OSA patients will allow targeted intervention and allow planning a specifc surgical procedure by allowing a delineation of the site and specifying degree and pattern of obstruction. It can also be used to exclude pathology like tumors. Dynamic sleep MRI and drug-induced sleep CT scan characterize the airway in OSA with the advantage of ability to evaluate the airway in a multiplane fashion in the sleeping state or a simulated sleep state.

Drug-induced sleep endoscopy (DISE) is an alternative to conventional endoscopy with the goal of more accurately representing patterns of collapse during the sleeping state.

#### **<IP_ADDRESS> Acoustic Refex Ion Test**

In this test, sound waves are projected into the airway and are refected into the tube to a computer which creates an image that determines the location of obstruction. This can also predict the effect of mandibular advancement and protrusion on upper airway.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.3** Narrowing of oropharynx and long upper airway length in OSA

#### **71.8 Clinical Features (Tables 71.2 and 71.3)**

#### **71.9 Treatment Modalities**

OSA is a chronic condition that would require multidisciplinary management over a long period of time. There is a myriad of options to treat the condition ranging from behavioral to medical to surgical options. The success of treatment would have to ensure the voluntary active participation of the patient.

#### **71.9.1 Positive Airway Pressure [13]**

Continuous positive airway pressure (CPAP) is usually the frst line of treatment for OSA. It works on the principle of binding the upper airway in an open position to improve patency during sleep (Fig. 71.4).

This was frst described by Sullivan [14] in 1981. The pneumatic splinting action is effective in reducing the AHI. PAP may be delivered in either continuous (CPAP), bilevel (BPAP), or auto titrating (APAP) modes. CPAP is the frst line of treatment for moderate to severe OSA and may be used occasionally in mild OSA. CPAP has also found to be effective as an adjunctive therapy to alter blood pressure in OSA patients having hypertension.

Some of these patients may elicit intolerance for CPAP therapy. In these cases, BPAP, pressure relief, or APAP can be considered as an alternative. In addition to its splinting

#### **Table 71.2** Symptoms of OSAS

#### **Table 71.3** Signs of OSAS

action, CPAP increases vagal tone, cardiac output, and stroke volume and decreases systemic vascular resistance, and there is reduced risk of cardiovascular mortality.

Compliance with nasal CPAP (nCPAP) ranges from 50 to 89% [15]. Reasons for noncompliance are usually due to tolerance problems like dry mouth, conjunctivitis, rhinorrhea, skin irritation, pressure sores, nasal congestion, and epistaxis. Other less common causes of noncompliance include aerophagia, chest discomfort, and bed partner intolerance or psychological problems arising from lack of motivation, claustrophobia, and anxiety.

Though there is no established known lower limit of nightly use below which nCPAP therapy is ineffective, it is suggested that 3.4 h per night of nCPAP use may be adequate to improve cognitive function and quality of life.

#### **71.9.2 Behavioral Strategies [16]**

Behavioral strategies have also been used as treatment methods in OSA. These include weight loss, regular exercise, positional therapy, and sleep hygiene which involves alcohol abstinence and consumption of sedatives before sleep.

Sleep position while supine can decrease the lateral upper airway dimensions, particularly while in the supine position.

**Fig. 71.4** CPAP usage

Therefore, in positional therapy, the patient is kept in a nonsupine position.

#### **71.9.3 Oral Appliances [17]**

The primary role of oral appliances (OAs) is to enlarge the posterior oropharyngeal airway space, leading to reduction of chances of the upper airway collapsing during sleep. They are ideally indicated in mild and moderate cases of OSA who are noncompliant/poorly compliant to nasal CPAP. Oral appliances are of two types: tongue retaining or mandibular repositioning.

protrusive capacity. This is followed by polysomnography to check the effcacy.

It is mandatory for patients using MRD to have adequate number of teeth to seat the appliance. There should not be any deleterious TMJ disorder, and the patients should have an adequate range of jaw motion and adequate manual dexterity and should be motivated to use the appliance.

The MRD device is customized and the material used is fexible polyamide.

In general, OAs are either titratable or non-titratable. Titratable OAs permit varying amounts of mandibular protrusion. Non-titratable OAs hold the mandible in a single protrusive position without any possibility to change the position during treatment. Some of the non-titratable devices are a simple splint, bionator, Karwatsky activator, or Herbst appliance [20].

#### **71.9.4 Surgical Treatment of Obstructive Sleep Apnea** [21] (Table 71.4)

Surgical procedures to correct or treat OSA essentially provide site-specifc treatment to increase airway size and decrease airway resistance, thus reducing the effort required in breathing. The site of obstruction is specifc to each patient and is as unique as fngerprints. Therefore, one needs to know which the most appropriate procedure is to guarantee success. Since no single factor is predictive of OSA, the signifcance of a thorough physical examination and imaging to

Mandibular Repositioning Device (MRD) MRD

During sleep there is restricted airway space ©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.5** Mandibular repositioning device

**Table 71.4** Common surgical procedures for OSA by site

identify the target site of airway resistance cannot be over emphasized.

increases airway space

*Tracheostomy* has been used to bypasses the upper airway and is thus a successful modality in treatment, but the morbidity associated with it limits its application.

Factors in the nasal cavity may also play a role in infuencing the pharyngeal stability through abnormalities like septal deviation and inferior turbinate. *Nasal surgery* to remove these abnormalities can improve nasal airfow, thus having a positive effect on OSA.

*Multiple surgical procedures* of the palate like uvulopalatopharyngoplasty (UPPP), which involves removal of the tonsils, uvula, and posterior velum in patients with large tonsils and relatively normal palatal position, are also good adjunctive procedures.

UPPP can also be done assisted by lasers allowing more precise incision and excision than conventional surgery. It also has the advantages of avoiding the need for general anesthesia and with minimal bleeding.

*Tonsillectomy with adenoidectomy* is the usually frst line of surgery for children with OSA without signifcant craniofacial anomalies.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.6** Genioglossal advancement

*Tongue reduction* is also a part of the surgical option in enlarges tongue cases where partial glossectomy can reduce the tongue volume.

Surgical procedures of the genial segment of the mandible like *Genioglossal advancement* moves the genial tubercles forward along with the genioglossus muscle, resulting in a more forwardly positioned base of tongue. In addition, it also causes the forward movement of the hyoid bone. This shift increases the posterior airway space and avoids the collapse of its walls during the REM phase of sleep. There are a lot of modifcations of the genial advancement procedures.

The standard procedure moves the whole genial segment including the chin. A modifed technique allows the surgeon to advance the genial tubercle without altering the normal anatomic position or shape of a patient's chin by only moving the rectangular bony component involving the tubercle (Fig. 71.6).

*Hyoid myotomy* involves the detachment of infrahyoid muscles and moving the hyoid forward and upward and fxing it with sutures. Another procedure moves the hyoid forward and downward with excision of the lesser cornu and fxing the hyoid anterior to the thyroid cartilage by sutures.

Surgical procedures can also be performed at different levels either concomitantly or in a staged manner. This is done when patients have more than one site of obstruction.

*Hypoglossal nerve stimulators* (HGNS) are a new addition to the armamentarium for treatment of OSA. It was approved by the FDA for treatment of moderate to severe OSA in 2014 [22].

The device which acts like a pacemaker monitors the breathing patterns and gets activated during sleep to stimulate the hypoglossal nerve, thus controlling upper airway muscles.

*Maxillomandibular advancement (MMA)* is undoubtedly the most successful surgical technique in OSA. This advantage of this procedure is the effect in correcting airway obstruction at multiple levels. The surgical advancement of the maxillomandibular skeletal framework corrects the airway collapsibility at the nasopharyngeal and oropharyngeal levels and is ideal in patients with moderate and severe OSA who exhibit multilevel obstruction.

The Le Fort I osteotomy of the maxilla along with mandibular sagittal split osteotomy is performed for advancing maxilla and mandible, thus increasing the airway space as it draws the base of the tongue and soft palate forwards (Fig. 71.7).

Achieving *MMA by distraction* is another alternative technique, especially in cases of TMJ ankylosis (Figs. 71.8 and 71.9) where a defcient mandible in the sagittal plane is primarily responsible for the obstructed airway.

The dimensions of maxilla and mandible can also be increased in the transverse plane by distraction resulting in increase in the dimensions of nasopharynx, oropharynx, and the nasal cavity along with movement of tonsillar pillars and the musculature of the velum. Maxillomandibular transverse distraction osteogenesis can be concomitantly be performed with their sagittal advancement for a more effective form of treatment MMA alone.

#### **71.10 Adjunctive Therapies**

#### **71.10.1 Bariatric Surgery [23]**

Weight loss procedures through bariatric surgery is indicated in patients with a body mass index (BMI) ≥ 40 kg/m2 or those with a BMI ≥ 35 kg/m2 with important comorbidities especially when dietary attempts are ineffective.

#### **71.10.2 Medications [23]**

Pharmacologic agents can on occasion be used with some degree of success in treating OSA by increasing glossopharyngeal neurologic activity or decreasing REM sleep.

Protriptyline, a tricyclic antidepressant reduces the frequency of apnea and desaturation in non-REM sleep and suppressing REM activity. It also increases the tone of the upper airway muscles. The anticholinergic activity of the drug however limits its use.

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.7** Maxillomandibular advancement and its effect on the airway

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.8** Compromised airway in ankylosis ©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.9** Improved airway after mandibular distraction in a TMJ ankylosis case

Theophylline reduces the episodes of apneas and hypopneas, but the quality of sleep deteriorates.

Modafnil is a wake-promoting medication that can improve residual daytime sleepiness in OSA patients despite regular use of CPAP. It is however avoided in patients who are noncompliant with CPAP. The adverse effects of these drugs are headache and nervousness.

Topical nasal corticosteroids have also been recommended in patients suffering from concurrent rhinitis.

#### **71.11 Conclusion**

Obstructive sleep apnea is a multi-factorial and multi-level condition whose management needs to be customized for every patient after a correct diagnosis. Treatment is regulated starting with the non-surgical options and moving to specifc site surgical procedures depending on the area of involvement.

#### **71.12 Case Scenario**

A 12-year-old female patient with history of sleeping diffculty due to airway obstruction.

Clinical features: Retruded chin, incompetent lips, dry mouth, short chin throat distance (Fig. 71.10).

Preoperative radiographic fndings: Defcient mandible, posteriorly placed menton, narrowed oropharynx (Fig. 71.11).

©Association of Oral and Maxillofacial Surgeons of India

Treatment plan: Mandibular advancement of 10 mm by distraction (Fig. 71.12).

Post op fndings: Improved profle, no episodes of apneas hypopneas (Figs. 71.13, 71.14 and Box 71.2).

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.11** Preoperative cephalogram

#### **Box 71.1** Preoperative PSG report

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.12** Mandibular distraction

©Association of Oral and Maxillofacial Surgeons of India

#### **Fig. 71.13** Postoperative profle of the patient

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 71.14** Postoperative cephalogram showing improved airway

#### **Box 71.2** Post distraction PSG report

#### **References**

#### **Suggested Reading**

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

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**Part XIX**

**Developmental Deformities of the Oral and Maxillofacial Region**

**72**

Pritham N. Shetty, Jaideep Singh Chauhan, Mamatha Patil, Neha Aggarwal, and Dipesh Rao

#### **72.1 Introduction**

A cleft lip [CL] is defned as a congenital defect in lip continuity due to an embryological malformation. Cleft lip and palate [CLP] have an overall incidence of 1 in 1000 live births [1]. For different ethnicities, the incidence varies. Like other facial deformities, cleft lip and palate produce a considerable degree of disfgurement and functional impairment. A comprehensive treatment involving a cleft surgeon, otolaryngologist, geneticist, speech pathologist, orthodontist and others are required at multiple stages right from infancy to adulthood. A successful lip repair requires careful consideration of presentation of the cleft, the availability of tissues or the lack thereof and effect of intervention on growth and function. We have tried to simplify this concept, keeping certain key points in mind necessary for comprehension of the subject. In this chapter, we have discussed embryology, anatomy and clinical presentation of cleft as an integrated phenomenon for better understanding of cleft lip. The author's technique of cleft lip is discussed in a stepwise manner.

**Electronic Supplementary Material** The online version of this chapter (https://doi.org/10.1007/978-981-15-1346-6\_72) contains supplementary material, which is available to authorized users.

P. N. Shetty (\*)

OMFS, Bangalore Institute of Dental Science, Bangalore, India

J. S. Chauhan

#### M. Patil

Sparsh Hospital Bommasandra Industrial Area, Bangalore, India

N. Aggarwal

Cleft and Craniofacial Surgery, Meenakshi Cleft and Craniofacial Centre, Chennai, India

#### D. Rao

Bhagwan Mahaveer Jain Hospital, Bangalore, Karnataka, India

#### **72.1.1 History of Cleft Lip Repair**

The enigma of cleft lip and the historic journey to repair the defect has been well described in the narrative book by Millard [2].The excerpts from it illustrates the documentation of the frst cleft lip repair in the year 390 AD where an unidentifed Chinese physician cut the edges of the cleft and stitched it together with a postoperative order of limited lip movements for the next 100 days. The need to identify an ideal technique was derived on the basis of the anatomical outcome of the repair and also the postoperative scarring. The concepts of cleft lip repair have evolved from straight line repairs to a variety of techniques using various cutbacks, triangles, z-plasties and other faps.

The techniques for cleft lip can be broadly classifed into:

We will discuss certain techniques to explain the evolution from a historical point of view. The rotation-advancement technique with its modifcations will be discussed later in this chapter.

### **72.2 Embryology**

#### **72.2.1 Development of the External Face**

The face is derived from two sources: the frontonasal process that covers the forebrain (neural crest origin) and the tissues of frst pharyngeal arch (mixed mesoderm and neural crest origin). These tissues surround the oropharyngeal membrane. From the frontonasal process, two medial nasal processes and lateral nasal processes arise [3]. The frst pharyngeal arch gives

© The Association of Oral and Maxillofacial Surgeons of India 2021 1593

Department of Maxillofacial Surgery and the Smile Train, CHL Hospital, Indore, India

K. Bonanthaya et al. (eds.), *Oral and Maxillofacial Surgery for the Clinician*, https://doi.org/10.1007/978-981-15-1346-6\_72

rise to a pair of mandibular processes and a pair of maxillary processes from which palatal processes arise [3]. The maxillary prominences continue to grow medially, compressing the medial nasal prominences towards the midline, subsequently meeting the lateral nasal processes and then the lower part of the medial nasal processes (Figs. 72.1, 77.1). This lower part is known as the globular or premaxillary process. The components derived from various parts are given in Table 72.1.

Abnormalities throughout this complicated developmental process occur in the most severe congenital forms if they develop early in facial embryogenesis (4–8 weeks) to the relatively minor problems developing later (8–12 weeks). Cleft lip varies from a notch in lips red border to extending into the foor of nostril and the alveolar ridge. It may be unilateral or bilateral (Fig. 72.2). Some other forms of facial clefts have also been described in a pictorial form as a result of failure of fusion of the same processes but in a different trajectory and various permutations and combinations (Fig. 72.3).

**Table 72.1** Components of face derived from various prominences

©Association of Oral and Maxillofacial Surgeons of India

**Fig. 72.1** (**a**–**d**) Development of the face. (**a**) Lateral nasal and medial nasal swellings that surround the nasal placodes appear on the frontonasal process (**b**) Paired maxillary processes grow medially, compressing

the medial nasal prominences towards the midline. (**c**) Medial nasal processes fuse with each other, lateral nasal processes and the maxillary processes. (**d**) Complete development of the nose and upper lip

**Fig. 72.2** Relation of embryological derivative to the anatomical and clinical description of cleft lip

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**Fig. 72.3** Embryology of various facial clefts