Asian Malar and Mandibular Surgery

Aesthetics of the malar-mandibular area

High cheekbones and a distinct mandibular contour characterize the appearance of East Asian persons, especially those of Korean and Japanese descent. In the West, such features are valued, and these areas are frequently enhanced for optimal aesthetic appearance. However, because of the more delicate topography of the typical Asian face, zygomas and mandibular angles that are overly prominent upset the balance, rendering the face overly flat, wide, and square.

In addition to its undesirable aesthetic appearance, in some East Asian cultures the prominent zygoma and mandibular angle have traditionally been associated with negative personal characteristics. On occasion, this can lead to difficulty finding a spouse or discrimination in the workplace.

For these reasons, Asian patients who might hesitate to have other types of surgery are willing to undergo reductive correction of these areas.

Surgeons must recognize that patients seeking bone-contouring surgery, as in other aesthetic surgeries performed on Asian persons, have a desire to improve their appearance; they are not attempting to achieve an appearance more typically associated with a western European person. Preservation of ethnicity remains the cornerstone of aesthetic surgery performed on Asian persons. A mistaken presumption on the part of the surgeon that the Asian patient is seeking an appearance more typically associated with a white person leads to great disappointment for the patient and, eventually, the surgeon. ^{[1, 2]}

Malar prominence

Onizuka proposed shaving or burring-down the prominent portions of the zygoma, usually the body, through an intraoral incision. ^[3] For persons with a wide arch, Watanabe proposed resecting the arch. ^[4] Yang accomplished an infracture of the zygoma with an intraoral-preauricular approach.

Baek et al considered the apparent prominent zygoma in Asian patients to be predominantly a malposition of the zygoma. ^[5] They proposed a repositioning operation that involves performing an osteotomy at the arch-body junction, performing a second osteotomy at the posterior arch, and repositioning the segment superiorly.

Mandibular angle prominence

Pacific Asian persons frequently have prominence of the mandibular angle and hypertrophy of the masseter muscle. This condition is frequently referred to as benign masseteric hypertrophy, but the relationship of this medical condition, frequently accompanied by pain, to the desires of a patient seeking an aesthetic appearance is not completely clear. Nevertheless, surgical techniques for benign masseteric hypertrophy remain applicable for correction of the prominent mandibular angle.

Resection of the lateral portion of the bone, contouring the posterior border of the mandible with and without removal of the masseter muscle, has been performed. The trend has been to perform the procedure through an intraoral approach whenever possible.

More recently, the use of botulinum A or B toxin has been reported for the correction of masseteric hypertrophy.

Malar Reduction Surgery

Classification of deformities

The zygoma consists of the body and the arch, either of which can be prominent. Most frequently, the defect involves the lateral portion of the body at the origin of the arch. Therefore, this is the area most frequently addressed surgically, reducing the bulk by burring the anterolateral portion of the zygomatic bone. This is followed by creating an osteotomy just lateral to the burred area, at the body, and another osteotomy at the origin of the arch. The intervening segment is then medially mobilized (in-fractured). ^[5]

Prominence of the zygoma occurs ideally in isolation; thus, correction leads to a balanced, narrower face. However, it also occurs in association with a broad skull base, as observed by Watanabe. ^[4] Improvement in facial contour is less dramatic in these patients because bitemporal width remains unchanged even after the intermalar distance has been narrowed. These patients should receive appropriate preoperative counseling. In addition to the clinical features of the deformity, the patient’s perception of the deformity is also important. The surgeon must understand this perception before commencing surgery. This should be discussed during the initial evaluation. ^[6]

The posterior mandibular angle should be evaluated because correction of the malar area exaggerates any prominence of the mandibular angle. This situation is analogous to the relationship between the nose and chin complex.

Prominent mandibular angle

The mandibular angle can be prominent on the frontal view, lateral view, or both views. The prominence can involve primarily the bone, the masseter muscle, or both. Analysis of the problem by direct examination and by radiographs reveals the problem. The surgical correction is then directed appropriately.

Frequency

Requests for correction of malar and mandibular angle prominence are common in metropolitan areas with large East Asian populations. ^[7] Occasionally, male patients seeking a sex change may request these operations.

The etiology of this condition is unknown.

Although the etiology of benign masseteric hypertrophy is usually unknown, masseteric hypertrophy is thought to be due to work hypertrophy, such as in habitual jaw clenching or teeth grinding. Interestingly, benign masseteric hypertrophy is frequently found among Korean persons who favor dried squid, a tough and chewy delicacy.

The etiology of prominent malar bones is more obscure. Although it can occur in isolation, it frequently occurs in conjunction with benign masseteric hypertrophy. According to Baek et al, hyperostosis of the malar bone may occur at the attachment of the masseter muscle, in the same manner as hyperostosis of the mandible. ^[8]

Patients requesting zygoma reduction surgery may simply wish to have a more balanced appearance. East Asian cultures value a small face, and wide cheekbones appear to make the face bigger. In other cases, patients may attribute some misfortune in their life to the zygomatic prominence and wish it corrected for this reason.

The patient with a prominent mandibular angle generally seeks aesthetic improvement. A prominent jawline creates a masculine appearance that may be undesirable. Because Asian beauty emphasizes subtlety, a prominent jawline throws off the balance of subtle midfacial features (nose, chin) by overpowering the mid face. Reducing the jawline restores the balance. When it comes to the prominent jawline, patients may have a significant muscle component, bone component, or both.

Indication for malar reduction is in a patient who is emotionally stable and has realistic expectations of the outcome. The ideal patient for cheekbone reduction has a narrow skull base and maxilla but an isolated prominent malar eminence or overly wide zygomatic arch. In these patients, infracture of the zygoma results in a dramatically reduced facial width and a desirable outcome. Zygomatic infracture does not produce the desired result of a patient with a wide skull base because the face remains wide even after the zygomatic infracture.

The ideal jawline reduction candidate has a prominent mandibular angle extending laterally, away from the neck. The technical details of the surgery make it difficult to reduce the bony structures if the mandibular angle curves inward, toward the neck. Patients with hypertrophic masseter muscles in conjunction with a prominent bony component benefit from removal of the inner half of the masseter muscle along with the bone.

Zygoma

The anatomy related to correction of zygoma fractures remains relevant, except that no orbital component is involved. Bear in mind that the frontal branch of the facial nerve can, on occasion, sustain traction injury. Careful subperiosteal dissection should preclude actual transection of the nerve. Exercise extreme caution when using burs, if used at all, because of the proximity of the facial nerve. When a bur is required at all, the author prefers a guarded bur.

Mandibular angle prominence

Dense fibers attach the masseter along the posterior angle of the mandible, necessitating sharp dissection in this area. The marginal mandibular nerve and facial artery lie at the anterior border of the masseter and are at risk. Vessels, if lacerated, may retract beneath the mandible, necessitating an incision in the neck for control. Preoperative discussion is advisable to make patients aware of the possible need for a 2-cm neck incision to control possible bleeding or remove bony chips that are otherwise inaccessible from an intraoral approach.

Patient selection is critical in these cases. The patient should have realistic expectations of the outcome of surgery. The ideal patient to undergo zygomatic reduction has an otherwise narrow face, and correction of the isolated prominent zygoma can lead to an excellent aesthetic appearance. However, if the patient has a generally wide face (and skull base), zygomatic reduction may not dramatically improve the patient's appearance.

For mandibular angle surgery, preexisting asymmetries and the probability of some postoperative asymmetry should be discussed with the patient. Patients should accept the possibility of a neck incision as necessary under extreme circumstances.