Three-dimensional endoscopic midface enhancement: a personal quest for the ideal cheek rejuvenation.

Standard face-lift techniques are excellent for the treatment of the jawline and neck. Treatment of the area between the lower eyelid and the corner of the mouth required the development of techniques in the intermediate lamella of the face. Alternative techniques of subperiosteal dissection by means of lower eyelid incisions were described with good aesthetic results but at the expense of increased morbidity and complications. All these techniques were also two-dimensional manipulations of the soft tissues of the face. The author presents a different approach that he believes is close to the ideal in terms of safety, morbidity, and complications.Although midface rejuvenation may be performed alone, it is more commonly done as a component of total facial rejuvenation. The midface is approached by means of a combination of a temporal slit incision and an upper oral sulcus incision; no eyelid access is used. Fifty percent of the midface dissection is performed under direct visualization, and 50 percent is performed under endoscopic control. Dissection of the temporal area is done under the temporoparietal fascia down to the zygomatic arch. The anterior two-thirds of the zygomatic arch periosteum is elevated along with a few millimeters of the intermediate temporal fascia and the fascia of the masseter muscle. The subperiosteal dissection of the zygoma and maxilla is completed with the medial extension of the dissection just medial to the infraorbital nerve. The orbital fat pads are released by means of intraoral route, and the lateral and middle fat pads are advanced over the orbital rim and fixed to the masseter tendon and the periosteum of the maxillary shelf at the intraoral incision. Three suspension points are typically used on the midface, each one with a different action. All are anchored to the temporal fascia proper. The vascularized Bichat's fat pad is mobilized and fixed with 4-0 polydioxanone sutures. This provides a volumetric cheek augmentation and improvement of the jowl. The inferior malar periosteum and fascia is used for malar imbrication with 4-0 polydioxanone sutures. This provides an anterior projection of the cheek and elevates the corner of the mouth. The suborbicularis oculi fat is used for en bloc vertical suspension of the cheek. This also improves the infraorbital V deformity.This technique has been used in close to 200 patients over the last 5 years. The complications have been minimal: two cases of temporary paresis of the levator of the upper lip, one case of paresis of the orbicularis oris (unilateral), one case of buccinator muscle dysfunction, and two moderate infections that were treated with simple drainage. The degree of facial edema has been minimal compared with the open or the transblepharoplasty approach. Typically, patients can return to work 2 weeks after surgery.The three-dimensional endoscopic midface enhancement provides a technique of midface remodeling that provides the missing dimension (volume) to the rejuvenation of the midface. This can be done with a minimal rate of complications, and the aesthetic results surpass by far the results of other midface techniques previously described by the author.     

Rejuvenation of the midface by elevating the malar fat pad: review of technique,cases, and complications

The midface is an area where definite and consistent improvement is still hard to achieve. Vertical suspension of the malar fat pad is an effective midface lift that complements facial rejuvenation to obtain an overall appearance of youth and beauty while maintaining the personal features of the patient. To substantiate its effectiveness, the authors evaluated the complications and long-term results of the malar fat pad elevation proper and in conjunction with other facial procedures. A retrospective review of the medical records of 458 consecutive patients who underwent malar fat pad elevation by the senior author (B.C.D.) from January of 1994 to January of 2000 was conducted. Because 14 patients had their malar fat pad re-elevated, the number of midface lifts totaled 472. Of these, 437 had a combined superficial musculoaponeurotic system excision and tightening, 19 had a combined limited superficial musculoaponeurotic system plication/imbrication, and 16 had elevation of the malar fat pad only. Elevating the malar fat pad appears to be a sound, straightforward, and effective means of rendering a youthful midface. It consistently reshapes the malar eminence, softens the nasolabial fold, and rejuvenates the lower eyelid. This technique provides lasting results, with an acceptable complication rate. Facial nerve injury, in particular, was infrequent and temporary. In addition, the prehairline scar happened to be quite inconspicuous, especially in patients older than 55 years. This experience confirms that malar fat pad elevation is a safe and effective method to rejuvenate the central third of the face.     

The evolution of the midface lift in aesthetic plastic surgery

The midface lift has recently gained significant popularity with many surgeons. It allows the surgeon an opportunity to achieve greater facial harmony with facial rejuvenation procedures by correcting midfacial atrophy, addressing the tear trough deformity, and correcting the perceived malposition of the malar fat pad. This article examines the history of midfacial procedures. Surgical attempts at improving the aging face have evolved from minimal excisions and skin closure to aggressive dissections at multiple planes. The midface target area is peripheral to classic approaches, and its correction has required further anterior dissection from a distance or direct access centrally. Ultimately, conquering the stigmata of midface aging is entirely related to vectors and volume.     

Meloplication of the malar fat pads by percutaneous cable-suture technique for midface rejuvenation: outcome study (392 cases, 6 years' experience)

The aging anterior midface is restored by reversing the contour undulations produced by sagging of the malar fat pad complex toward the nasolabial line. The convex irregularities include the exposed bulges of the post-septal fat, the unveiled malar bag, and the prominent nasolabial fold. The depressed irregularities are represented by the cresent-shaped hollow at the lid-cheek junction, the accentuated nasojugal groove, and the deepening nasolabial line. Repositioning of the ptotic malar fat pad, among other elements of meloplasty, represents a key procedure. In this study, the malar fat pad has been defined as a fan-shaped structure by external anatomic landmarks that correlate closely to the findings in cadaveric dissections and clinical cases, confirmed by the findings of spiral computed tomographic scanning. A simple but powerful adjustable and long-lasting percutaneous suture elevation technique was developed over the past 6 years by the senior author (G.H.S.) to reposition the fat pad in a superolateral direction. Through a dot incision within the nasolabial line, a permanent CV-3 Gore-Tex (or 4-0 clear Prolene) suspension suture, looped through a Gore-Tex anchor graft, suspends the malar fat pad in a direction perpendicular to the nasolabial line. A second suspension system is identically passed through another lower dot incision to broaden the repositioning vectors on the malar fat pad. Tension on each of the paired suture ends elevates the malar fat pad by 1 to 3 mm as measured from the nasolabial dot incisions. The sutures are fixed to the deep temporal fascia through a Gore-Tex tab, effectively stabilizing the soft-tissue repositioning. This maneuver may be performed in younger patients who present with an isolated malar fat pad ptosis without excess facial skin. The procedure may also be incorporated into open rhytidectomies to address this recalcitrant area along with superficial musculoaponeurotic system tightening. A total of 392 patients since 1995 underwent suture elevation of the malar fat pads. An outcome study indicated that the usage of two permanent sutures with Gore-Tex anchor grafts since 1998 resulted in improvement in midface rejuvenation of over 82 percent. Early and late complication rates were small and temporary. Patient acceptance was excellent, indicative of the benefits of anatomic repositioning of the malar fat pad complex.     

Achieving aesthetic balance in the brow,eyelids, and midface

An approach to the brow, eyelids, and midface emphasizing release and advancement of the orbicularis oculi muscle, conservative removal of orbital fat, preservation of the nerve supply to the orbicularis oculi muscle, and avoidance of canthal division was evaluated in 100 consecutive patients. The technique describes the selected release of three key retaining ligaments to the forehead, brow, and upper eyelid; mobilization of the lateral retinaculum and division of the lower lid retaining ligament; and division of the midface malar retaining ligament (zygomatic-cutaneous ligament). Preservation of motor branches to the lower lid orbicularis is stressed. Of significance to this series of patients is the inclusion of 50 patients with morphologically prone lower eyelids defined as atonic lower lids, exorbitism, and/or negative vector orbits. Three sites had failure of brow fixation, two patients had midface asymmetry requiring revision, and three patients failed to have complete correction of their preoperative lower lid retraction. There was zero incidence of scleral show or lower lid retraction that was not present preoperatively. No patients required division of the lateral commissure with canthoplasty, taping or suture suspension, massage, or steroid injections. Only two patients required division of the deep head of the lateral canthus, and these patients were noted to have had lateral canthal malposition preoperatively.     

Transblepharoplasty lower eyelid and midface rejuvenation: part I. Avoiding complications by utilizing lessons learned from the treatment of complications

Transblepharoplasty midface elevation has become a common aesthetic procedure in recent years. As new techniques have been utilized, complications have arisen. Management of these referred complications has resulted in the development of a technique that elevates the midface and restores the normal position and shape to the lower eyelid with minimal postoperative problems. Four principles must be followed to achieve satisfactory results. The orbicularis oculi/orbital septum bond must not be altered in midface surgery. The lateral canthus must be reattached to its normal anatomic location at the lateral orbital rim if there is lateral canthal tendon laxity. The orbital fat should be addressed via a transconjunctival approach, when necessary, to prevent middle lamella inflammation and orbital septum retraction. A suture at the inferior lateral orbital rim simulating the orbitomalar ligament, as well as orbicularis oculi muscle sutures, elevates the midface. Utilizing these steps, the midface and lower eyelid can be satisfactorily repositioned with minimal complications. This surgical approach can be utilized in all appropriate candidates but is especially useful in reoperative cosmetic surgery patients and the older patient population.     

Transblepharoplasty endoscopic subperiosteal midface lift

The use of endoscopy in the transblepharoplasty midface lift is essential for preventing the complications of facial nerve injury and bleeding. Complete observation allows precise dissection and release of all structures in the composite flap. This technique fully preserves the zygo-orbicular nerve plexus and prevents denervation of the orbicularis oculi and zygomaticus muscles. Blind dissection has a significant probability of denervation of the entire zygo-orbital muscle complex, and avulsion of the zygomaticofacial vessels, with associated postoperative bleeding complications. The modification involving suturing of the "vest" of the combined lateral orbital periosteal and superficial layers of the deep temporal fascia over the elevated "pants" of the orbicularis periosteal flap provides very secure fixation for suspension of the lower eyelid and midface. The use of slowly absorbable polydioxanone sutures for this technique prevents the problems caused by permanent sutures beneath the very thin skin of the lateral canthal area. Careful trimming of the prominent roll of the orbicularis muscle that often develops with suspension eliminates the uneven contour and yields a smooth lower lid appearance. The details and modifications described should decrease the complications and morbidity that can occur with this procedure and provide for a more precise and reliable procedure for rejuvenation of the lower eyelid and midface.     

A 5-year study of the transmalar subperiosteal midface lift with minimal skin and superficial musculoaponeurotic system dissection: a durable, natural-appearing lift with less surgery and recovery time

The transmalar subperiosteal midface lift is a simple, direct-approach procedure to be performed with a meloplasty. The entry into the midface is at the site of maximum suture tension, which allows for more elevation. The skin is elevated enough to expose the entry site, which is on the zygoma just cephalad to the origins of the zygomaticus muscles. Through a small hole at that site, a periosteal elevator is used for the midface dissection. This is a blind dissection, and the technique is described. The advantages of the technique are that there is (1) no lower-lid incision or risk of an ectropion, (2) a resultant tightening and elevation of the lower lid, (3) more elevation and durability because the zygomaticus muscle origins are elevated with the periosteum and are sutured to the very substantial deep temporal fascia, (4) a simple and fast procedure, and (5) no telltale sign of a face lift. Both the superficial musculoaponeurotic system (SMAS) and the skin are substantially elevated with the transmalar subperiosteal midface lift to the extent that they should be only minimally dissected. In the author's opinion, the extended dissection of the skin and/or the SMAS does not increase the amount of tissue lift and probably reduces it in most cases, considering that the goal is a natural look and not one that appears pulled or stretched. The skin is elevated only for exposure, and the SMAS is elevated only enough to create a preauricular SMAS-platysma flap to tighten the neck. With two fewer layers of dissection, there is significantly less postoperative swelling and recovery time. The article presents the technique, the results on 272 patients over a period of 5 years, and a discussion. No patients described have had secondary procedures such as lasers, so the transmalar subperiosteal midface lift can be evaluated on its own merit.     

The midface sling: a new technique to rejuvenate the midface

In the early 1990s, the midface became the focus of facial rejuvenation, and various techniques effected elevation by plicating, or on, the midface. Recent analyses of facial aging demonstrate that selective ptosis of the midfacial tissues lateral to the nasolabial fold results in an infraorbital hollow and deepening of the nasolabial fold. Therefore, the authors propose that the midface, from the lower portion of the cheek mass, will result in superior midface positioning. Since 1996, the authors have elevated the midface in select patients by placing a sling of prosthetic (Gore-Tex) or autogenous (tendon or fascia) material through the cheek mass. The sling is secured medially to the infraorbital rim using a nonabsorbable periosteal suture or a mechanical anchor. As variable tension is applied laterally toward the superficial temporal fascia, the sling functions as a fulcrum to return the cheek mass to a more youthful anatomical position. Elevating the cheek mass in this fashion fills the infraorbital hollow and results in amelioration of deep nasolabial folds and jowling. With a mean follow-up of 18 months, 50 patients treated with the midface sling report satisfaction with the procedure. There have been no instances of nerve damage, infection, or hematoma in the midface. None of the slings have required removal and ectropion has not occurred. Because of postoperative asymmetry in one patient, additional elevation of the ipsilateral cheek mass was performed by increasing the tension on the lateral cheek portion of the midface sling. Mathematical models demonstrate the biomechanical superiority of lift through the use of multiple vectors as compared with linear pull techniques. In this fashion, the midface sling supports the cheek mass, providing rapid, simple, and secure elevation. Because of the limited subcutaneous dissection, there is a reduced risk of facial nerve damage and cutaneous vascular compromise. Unlike with other techniques, the lateral portion of the sling may be easily identified through a small incision in the temporal scalp, facilitating subsequent postoperative adjustment of the midface suspension. Furthermore, because the entire cheek mass is permanently supported with an inelastic sling, the results may last longer than those with techniques that rely on sutures to plicate or lift portions of the superficial musculoaponeurotic system.     

Repositioning the orbicularis oculi muscle in the composite rhytidectomy.

While blepharoplasties are routinely done with face lift procedures, the improvement is accomplished by removing excess orbital fat with eyelid skin and muscle along the incisional line. The orbicularis oculi muscle remains intact as its inferior border, which has become ptotic and redundant with aging, and actually remains in the same position following a conventional lower lid blepharoplasty and rhytidectomy. However, by elevating the orbicularis oculi with the cheek fat and platysma in a composite face lift flap, and by excising the redundant inferior border of the orbicularis muscle, a total rejuvenation of the malar area is accomplished. The descent of the orbicularis oculi muscle is in an inferolateral vector, whereas the vector of facial aging is inferomedial. Thus, repositioning the orbicularis oculi is in a superomedial vector and is obligatory in a composite rhytidectomy.     

The anatomy and clinical applications of the buccal fat pad

The buccal fat pad is an anatomically complex structure that has great importance in facial contour. In properly selected individuals, judicious harvesting of buccal fat can produce dramatic changes in facial appearance by reducing the fullness of the cheek and highlighting the malar eminences. Using fresh cadaver dissection, the anatomy of the buccal fat pad is delineated and its relationship to the masticatory space, facial nerve, and parotid duct is defined. An intraoral approach for buccal fat harvesting is described based on these anatomic findings. Clinical experience manipulating the buccal fat pad for aesthetic modification of facial contour is illustrated.     

Laser blepharoplasty with transconjunctival orbicularis muscle/septum tightening and periocular skin resurfacing: a safe and advantageous technique

Carbon dioxide (CO2) laser blepharoplasty with orbicularis oculi muscle tightening and periorbital skin resurfacing is a safe procedure that produces excellent aesthetic results and diminishes the occurrence of complications associated with skin and muscle resection in the lower lid, particularly permanent scleral show and ectropion. The authors present a review of 196 cases of carbon dioxide laser blepharoplasty and periocular laser skin resurfacing performed at their center from April of 1994 to September of 1998. Of these cases, 113 patients underwent four-lid blepharoplasty, 59 underwent upper lid blepharoplasty only, and 24 underwent lower lid blepharoplasty only. Prophylactic lateral canthopexy was performed in 24 patients. Concomitant procedures (brow lift/rhytidectomy/rhinoplasty) were performed in 92 patients. The carbon dioxide laser blepharoplasty procedure resulted in no injuries to the globe, cornea, or eyelashes. Combined with laser tightening of the orbicularis oculi muscle and septum and periocular skin resurfacing, the transconjunctival approach to lower blepharoplasty preserves lower lid skin and muscle. Elimination of the traditional scalpel skin/muscle flap procedure results in a dramatically lower complication rate, particularly with regard to permanent ectropion and scleral show. Laser shrinkage of the orbicularis muscle and septum through the transconjunctival incision enables the correction of muscle aging changes such as orbicularis hypertrophy and malar festoons. The addition of periocular resurfacing enables the correction of skin aging changes of the eyelid that are not addressed by traditional scalpel blepharoplasty. In addition, lateral canthopexy constitutes an important adjunct to the laser blepharoplasty procedure for the correction of lower lid canthal laxity.     

Reduction of lower palpebral bulge by plicating attenuated orbital septa: a technical modification in cosmetic blepharoplasty

Bulging of the lower eyelid is regarded as a sign of aging. "Herniation" of the periorbital fat pads is traditionally regarded as the factor responsible for the change. Excision of fat pads, therefore, has been the mainstay of treatment in reducing the palpebral bulge in cosmetic blepharoplasty. The surgical excision of"excess" and "herniated" fat pads, however, causes problems such as lid ecchymosis, chemosis, lid contour irregularity, ectropion, and retrobulbar hematoma formation. The author proposes that the loss of fat pad support caused by the attenuation of the orbital septa, not herniation of the excess fat pads, is the major factor responsible for the bulge. The author further proposes that the functional integrity of the orbital septum can be restored by plicating the attenuated orbital septa with 5-0 absorbable sutures. This technique of invaginating the protruded fat pad was performed in 138 individuals (276 lower eyelids). The operation was technically simple, and the approach was "tissue friendly." The results obtained, with the exception of a mild degree of puffiness encountered soon after the surgery, were satisfactory. Morbidity was minimal.     

Reinforced orbitotemporal lift: contribution to midface rejuvenation

The changes in the aging face occur from progressive ptosis of the skin, fat, and muscle, in conjunction with bone absorption and cartilage atrophy. In the orbital region, hollowness and compartmentalization occur. Conventional face lift procedures correct only the skin flaccidity, and superficial musculoaponeurotic system techniques reposition the skin and platysma without repositioning the middle third of the face, creating an artificial jawline. Subperiosteal rhytidectomy disrupts the anatomy of the periorbita, which gives the patient a certain scarecrow aspect. Composite rhytidectomy associated with brow lift and blepharoplasty may offer better results, with improvement in the malar and orbital regions. The reinforced orbitotemporal lift (ROTEL) is a new procedure in a face lift that allows the orbicularis oculi muscle and all the structures connected to it to be elevated and stretched and the orbitotemporal skin to be raised, repositioning these structures and ending orbital compartmentalization. The result is an impressive improvement in the malar-orbitotemporal region, resulting in a natural and youthful appearance.     

A challenge to the undefeated nasolabial folds

Previous attempts to improve the nasolabial folds have been disappointing. By extending the face lift skin dissection to the nasolabial fold and up onto the malar prominence, reducing the fat of this fold by excision, and applying direct posterior retraction to the freed facial skin, rather dramatic improvement in the nasolabial folds have been achieved. This is a preliminary report with a follow-up of 8 months or less.     

A study of the long-term effect of malar fat repositioning in face lift surgery: short-term success but long-term failure

In 1990, the author reported on a series of 403 cases of deep plane face lifts, the first published technique describing the repositioning of the cheek fat, known as malar fat, in face lift surgery. This study examines the long-term results of 20 of the original series in an attempt to determine what areas of the rejuvenated face (specifically, the malar fat) showed long-term improvement. The results were judged by comparing the preoperative and long-term postoperative views in a half-and-half same-side hemiface photograph. The anatomy of the jawline (superficial musculoaponeurotic system [SMAS]), the nasolabial fold (malar fat), and the periorbital diameter were evaluated. The results confirmed that repositioning of the SMAS remained for longer than improvement in the nasolabial fold and that the vertical diameter of the periorbit did not change at all. The early results of malar fat repositioning shown at 1 to 2 years were successful, but the long-term results showed failure of the early improvement, manifested by recurrence of the nasolabial folds. There was, however, continuation of the improved results of the forehead lift and SMAS maneuvers of the original procedure. The conclusion is that only a direct excision will produce a permanent correction of the aging nasolabial fold.     

Lower blepharoplasty using bony anatomical landmarks to identify and avoid injury to the inferior oblique muscle

In the resection of redundant orbital fat during lower blepharoplasty, selective excision is performed from the medial, central, and lateral compartments. During transcutaneous blepharoplasty, the inferior oblique muscle is susceptible to injury because of its intimate association between the medial and central compartments. When performing a transconjunctival approach, the inferior oblique muscle is even more susceptible to injury because it lies in the direct path of dissection for fat pad exposure. Injury to the inferior oblique muscle can result in symptoms ranging from transient diplopia to a more debilitating permanent strabismus. Fresh cadaver heads were used to identify bony anatomical landmarks that would help to more accurately define the origin and body of the inferior oblique muscle. The orbital rim, infraorbital foramen, and supraorbital notch were chosen as guideline landmarks. The origin of the inferior oblique muscle was designated with respect to the above structures, and the muscle course was delineated. The inferior oblique muscle originates on the orbital floor, 5.14 +/- 1.21 mm posterior to the inferior orbital rim, on a line extending from the infraorbital foramen to 10 +/- 0.9 mm inferior to the supraorbital notch along the supramedial orbital rim. The muscle belly extends from this origin to its insertion into the posterolateral globe in an oblique direction toward the lateral canthal area. Identification of the orbital rim, infraorbital foramen, and supraorbital notch more accurately localizes the origin and course of the inferior oblique muscle, which may facilitate fat resection during lower blepharoplasty by preventing morbidity associated with inferior oblique muscle injury.     

Aesthetic and restorative midface lifting with hand-carved,expanded polytetrafluoroethylene orbital rim implants

The midface lift represents an important advance in aesthetic and reconstructive surgery. However, the need for reliable fixation along the orbital rim has been a significant challenge. Furthermore, volume is needed at the orbital rim, to compensate for long-term remodeling of the bone of the orbital rim and malar face. A technique using a hand-carved, expanded polytetrafluoroethylene implant that is permanently anchored to the orbital rim with titanium microscrews, creating a site for fixation of the advanced midface soft tissues, was developed. This report presents a retrospective, uncontrolled, case series of 41 consecutive patients who underwent transconjunctival midface operations with these implants, and it addresses a variety of midface aesthetic and reconstructive deficits. Only patients with at least 6 months of follow-up data were included in the study. To date, significant complications have been limited. The complications included two cases of implant palpability, with only one requiring surgical modification. One patient underwent implant removal because of skin breakdown and infection related to recurrent squamous cell carcinoma. One patient required revisional lateral canthoplasty for reasons of symmetry. On the basis of this series, hand-carved, expanded polytetrafluoroethylene implants seem to have significant advantages, compared with previously available orbital rim implants. These advantages include the ability to easily modify the implant for the individual anatomical needs, the creation of a secure anchor for fixation of advanced midface soft tissues, excellent tolerance of the implant material, and the ability to place the implant with limited exposure. The greatest disadvantage is the need for the surgeon to carve the implant, which requires time and carving skill. Despite this limitation, the technique is promising.     

Anatomical structure of the buccal fat pad and its clinical adaptations

Before performing plastic and aesthetic surgery around the buccal area, the authors reviewed the anatomical structures of the buccal fat pad in 11 head specimens (i.e., 22 sides of the face). The enveloping, fixed tissues and the source of the nutritional vessels to the buccal fat pad and its relationship with surrounding structures were observed in detail, with the dissection procedure described step by step. The dissection showed that the buccal fat pad can be divided into three lobes-anterior, intermediate, and posterior-according to the structure of the lobar envelopes, the formation of the ligaments, and the source of the nutritional vessels. The buccal, pterygoid, pterygopalatine, and temporal extensions (superficial and profound) are derived from the posterior lobe. The buccal fat pad is fixed by six ligaments to the maxilla, posterior zygoma, and inner and outer rim of the infraorbital fissure, temporalis tendon, or buccinator membrane. Several nutritional vessels exist in each lobe and in the subcapsular vascular plexus forms. The buccal fat pads function to fill the deep tissue spaces, to act as gliding pads when masticatory and mimetic muscles contract, and to cushion important structures from the extrusion of muscle contraction or outer force impulsion. The volume of the buccal fat pad may change throughout a person's life. Based on the findings of the dissections, the authors provide several clinical applications for the buccal fat pad, such as the mechanism of deepening the nasolabial fold and possible rhytidectomy to suspend the anterior lobe upward and backward. They suggest that relaxation, poor development of the ligaments, or rupture of the buccal fat pad capsules can make the buccal extension drop or prolapse to the mouth or subcutaneous layer. As such, the authors refined their methods and heightened their focus when using the buccal fat pad to perform a random or pedicled buccal fat pad fat flap or to correct a buccal skin protrusion or hollow.