Aesthetic Zygoma Reduction: Surgical Techniques for Asian Patients
Zygoma reduction is indicated in patients where the primary aim of surgery is reduction in the width of cheekbones to achieve smoother and more feminine facial aesthetic lines. Surgeons should evaluate the width of midface (bizygomatic width) and the protrusion of zygoma (volume and position of the zygomatic body) when evaluating patients where such a procedure is indicated. Intraoral high-L osteotomy is the most useful method to successfully treat a wide spectrum of zygomatic protrusions and is widely accepted as the treatment of choice for aesthetic purposes. The amount of ostectomy is determined by evaluating the volume of zygomatic body. The zygomatic body and arch are usually moved posteromedially during surgery; the point of maximal malar projection is evaluated and transposed to a new ideal position.
Zygoma reduction can be performed solely or in combination with other facial bone contouring procedures such as mandible reduction, genioplasty, or forehead augmentation. Soft tissue sagging, nonunion, malunion, and paresthesia are the most common complications of this procedure. Undercorrection and asymmetry are the most common aesthetically unfavorable sequelae and should be carefully prevented by proper preoperative planning and meticulous execution of surgical technique.
It is important for the surgeon to understand patient’s motivation for considering zygoma reduction. The aesthetic sensibilities of the Caucasian and Asian patients regarding the desired malar projection are diagonally opposite. Although beauty standards are getting harmonized between various cultural and ethnic groups due to the influence of media and globalization, it is not always appreciated by surgeons in the West that unlike Caucasians, who prefer an angular face with high and prominent cheekbones, Asians desire a slimmer face with narrow and smooth cheekbones. One reason for this difference is the shorter and wider facial contour in Asians compared with Caucasians. These characteristics are typical of the Mongoloid face (brachycephalic face), and are in contrast to the Caucasian face which tends to be slim and protrudes in an anterior–posterior dimension.
See below the bony facial morphology at the level of the cheekbone in axial section. Compare the (a) brachycephalic Asian face and the (b) dolichocephalic Caucasian face.
Surgical Planning for Zygoma Reduction for Asian Patients
The surgical plan is prepared once the characteristics of zygoma are determined. Variables in the reduction of zygomatic body are amount of ostectomy, medialization, setback, and vertical repositioning. Variables of zygomatic arch reduction are the amount of arch medialization and degree of shaving of the articular tubercle posterior to the osteotomy line. The amount of ostectomy is determined considering the volume of zygomatic body. The zygomatic body and arch are usually moved medially, posteriorly, and sometimes superiorly or inferiorly during surgery. The point of MMP is marked and its new ideal position is carefully planned
The overall facial shape, including mandibular prominence and facial length, should be considered in planning zygoma reduction. Particular care should be taken in patients with a long face, as excessive reduction carries the risk of making the face appear longer after surgery. Zygoma reduction is frequently performed in combination with mandible reduction and genioplasty. Total facial evaluation is mandatory. Preoperative consultation must include an in-depth discussion on the need for complimentary surgical procedures to enhance the aesthetic results of zygoma reduction to improve patients’ satisfaction with the surgical results.
As facial soft tissue is also an important component in zygoma reduction, it should be given due consideration to achieve a satisfactory aesthetic result. If a patient has thin skin with minimal cheek soft tissue, changes following zygoma reduction will be quite obvious with minimal prospect of soft tissue drooping. Such patients are ideal candidates for zygoma reduction. However, on the downside, visible bony step around the osteotomy, and palpable implant plates through the thin skin, may compromise the aesthetic result.
Surgical Techniques
The approach for zygoma reduction consists of both preauricular and intraoral approaches. The intraoral approach can be used solely; however, it is usually combined with a preauricular incision to minimize the dissection and the possibility of cheek drooping. An L-shaped osteotomy of the zygomatic body is the preferred method for patients with moderate-to-severe malar protrusion caused by a wide zygomatic arch and a prominent body. An L-shaped osteotomy is made in the anterior part of the zygomatic body and a separate osteotomy is made in the posterior part of the zygomatic arch. With or without removal of bone,3 a zygomatic segment is moved to the desired position and fixed with plates and screws. The L-shaped osteotomy technique can change both the zygomatic body and arch and has the advantage of controlling the degree of reduction as well as the shape after reduction.
Anaesthesia for Procedure
All patients are given general anesthesia with orotracheal intubation. Nasotracheal intubation can be used but is usually not required. About 3-cm upper labio-buccal vestibular incision is made on each side of the maxilla.4 The soft tissues are elevated superiorly and laterally through this incision in the subperiosteal plane. Dissection is limited to the area of the zygomatic body, the anterior wall of the maxillary sinus, and the lateral and inferior orbital rim. As the dissection extends superolaterally over the malar eminence, a portion of the origin of the zygomatic major and zygomatic-cutaneous ligaments may be partially divided from the bony surface.
Anterior Osteomy
An inverted L-shaped osteotomy line is marked over the malar eminence. This line generally extends medially from the lateral border of the orbital rim to just below the infraorbital foramen. The surgeon should be careful not to start the osteotomy too low from where the arch changes from a vertical to a horizontal direction, as this may result in insufficient volume reduction at the zygomatic body. The short limb of the osteotomy then turns at about a 90-degree angle toward the zygomaticomaxillary buttress. Great attention must be paid to avoid injury to the orbital contents or infraorbital nerve. A second, parallel line is drawn lateral to the first line to represent the strip of bone to be resected, allowing inset of the fragment.
See below the design of bone cuts in zygoma reduction. An inverted L-shaped osteotomy line is marked over the malar eminence. A second, parallel line is drawn lateral to the first line to represent the strip of bone to be resected. A posterior bone cut is made 2 to 3 cm anterior to the tragus.
The distance of the second line from the first line depends on the patient’s preference and the width of the zygomatic body. A wider parallel osteotomy can be made for greater reduction; however, the usual width of the strip is 3 to 5 mm. Double-blade reciprocating saws with a distance of 2, 3, 4, 5, 6, or 7 mm between the two blades were designed in the author's clinic and have proved to be very useful to achieve this goal. A simple osteotomy and repositioning of the zygomatic body alone usually cannot successfully reduce the size of the zygoma, necessitating ostectomy and removal of bone. The short limb of the osteotomy must be high enough to avoid the dental roots. Careful dissection is required in the zygomatic–pterygoid space to prevent injury to vessels, which may lead to profuse bleeding and postoperative bruising. Multiple retractors are placed and the cuts are made with a reciprocating saw starting from the superior lateral limb of the osteotomy. Next the superior medial cut, and finally the inferior transverse cut is made and the intervening bony fragment is removed.
Posterior Osteomy
Upon exposing the posterior part of the zygomatic arch, the course of the frontal branch of the facial nerve and the zygomatic arch is marked on the skin. About 1 cm vertical incision is made within the sideburn, 2 to 3 cm anterior to the tragus. This incision should lie posterior to the course of the facial nerve. The arch is identified after the dissection of the periosteum, and fine elevators are passed over the top and behind the arch and as far posteriorly as possible to ensure that the osteotomy is still anterior to the temporomandibular joint. A reciprocating saw is used to make this vertical osteotomy. When the posterior osteotomy is completed, the zygomatic segment should be free to move while remaining attached to the masseter. Additional bone distal to the osteotomy may be burred if necessary.
See below the position of the double-bladed reciprocating saw for anterior (a) and posterior (b) osteotomy.
Fixation
The osteotomized body and arch are positioned posteriorly and medially after the osteotomy, and the intervening segment is removed. The patient’s desired aesthetic outcome and preoperative planning are used to determine the 3D placement of the segment, making sure that there is good contact between bony surfaces. Bony gap predisposes to potential nonunion and future mobility of zygoma; this should be avoided by all means. Six hole miniplates with screws are placed to fix the anterior portion of the bony segment. All six holes should be filled with screws to prevent 3D rotation of the segment. A three-hole miniplate with screws is used to fix the posterior zygomatic arch portion of the bony segment, with two screws in the fixed part and one in the mobile part. Prebent titanium plates are extremely useful during this step because the bony segments are mobile and 3D positioning is difficult due to the limited surgical exposure. Positioning of the osteotomized segment is the most critical step for satisfactory postoperative results. The final position is adjusted taking into account any pre-existing asymmetry and intraoperative appearance to achieve the desired final outcome. An identical procedure is then performed on the contralateral side. Standard techniques are used to close the intraoral and skin incisions.
See below the rigid fixation of malar complex. (a) Applying a 6-hole plate to the zygoma body. (b) Applying a prebent miniplate to the zygomatic arch.
Common Reasons for Unsatisfactory Results
The most common reason for unsatisfactory aesthetic result following zygoma reduction is undercorrection of the zygomatic body. The main reason for this undercorrection is a very low osteotomy that fails to move MMP medially; another important cause is an insufficient excision of the bony fragment during ostectomy. In usual cases of zygoma reduction, L-shaped osteotomy is effective in reducing the width of the zygomatic body and repositioning the MMP point. However, our research shows that there are three different types of zygomatic protrusion:
• Type 1: Confined to the lower half of zygoma.
• Type 2: Broad zygomatic body protrusion.
• Type 3: Combined zygomatic and orbital rim protrusion.
More than one-half of patients have upper zygoma or orbital rim protrusion together with lower zygoma body protrusion (type 2 and type 3). Careful assessment of the extent of zygoma reduction is necessary. For maximal reduction, it is helpful to position the superior osteotomy line as close to the orbital rim as possible, using a high Losteotomy. In case secondary surgery is needed because of undercorrection, a new body osteotomy is performed on the medial side of the previous osteotomy. The intervening segment between previous and revision osteotomy can either be completely removed or care should be taken to secure the plate over two osteotomy sites to prevent its mobility.
Key Techniques to Avoid Complications
Repositioning of the osteotomized zygomatic complex is an important step in zygoma reduction. Deciding on the amount of bony resection and setback is a difficult judgment to make as there are no absolute guidelines to help with decision making. In general, we remove a strip of zygoma body ranging from 2 to 6 mm, set the zygomatic body back between 0 to 4 mm, and push the zygomatic arch in range from 0 to 5 mm. Surgeons have to decide regarding the precise amount of each element considering patients’ preference and their experience.
In some cases, transposing the zygomatic body and arch medially and posteriorly along with maximal resection of the zygomatic body results in a flat, square midface. Patients usually complain that their face looks too flat, and even wider, even though the actual width has been narrowed. To avoid this, the amount of body medialization should be individualized according to the shape of the face in the basal view. By changing the shape and position of the zygomatic body, we can create a midface fullness that appears more three-dimensional and youthful.
Inability to control the exact extent of movement and position of the osteotomized segment is a serious shortcoming, especially in the field of aesthetic surgery. Although fixation may not be essential in zygoma reduction using the in-fracture method, rigid fixation is necessary when one or more osteotomies are performed. Only rigid fixation to both the zygomatic body and arch can guarantee precise repositioning and stability. If rigid fixation is not used after osteotomy, undercorrection, asymmetry, and relapse can occur after surgery. Rigid fixation is also critical for the prevention of nonunion and postoperative pain. To prevent undesirable movement of bony fragments attached to masseter muscle, muscle relaxants are usually advised for 2 weeks.
Minimally invasive minizygoma reduction surgery can be performed under local anesthesia in patients with a wide zygomatic arch with minimal body protrusion. Greenstick osteotomy is performed on the zygomatic body through a temporal incision. Osteotomy on the zygomatic arch is similar to the standard technique. After an inward transposition of the osteotomized zygomatic segment is achieved, rigid fixation is performed on the zygomatic arch with miniplates and screws. The surgery has the advantage of stability of bony segments, fast recovery, and minimal postoperative swelling.
Reference
Aesthetic Zygoma Reduction in Asian Patients (2020)
Complications in aesthetic malar augmentation (1983)
Reduction malarplasty using osteotomy and repositioning of the malar complex: clinical review and comparison of two techniques (2003)
Reduction malarplasty through an intraoral incision: a new method (2000)
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