Midface Surgery-Anatomic Considerations

In the past 15 years, oculofacial surgeons have been grappling with what is essentially a new frontier in the field: midface surgery. In contrast to many of the classic techniques of oculoplastic surgery, midface surgery is still in a process of rapid evolution and flux. Progress in midface surgery has been slowed by past paradigms of lower eyelid surgery. Specifically, addressing many of the deficiencies of the midface requires that the surgeon necessarily correct midface bone changes as well as involutional midface soft tissues changes. Until recently the adult projection of the maxilla was considered static except in cases of trauma.

Recent studies have demonstrated that over time the adult maxillary face and orbital rim retrudes and inferiorly rotate. It is not clear if these changes are simply the result of long term bone remodeling or if osteoporosis also contributes to bone loss at the orbital rim. What is clear is that after the mid-twenties, maxillary hypoplasia becomes an increasing prevalent feature of the aging face. As an individual enters the forties, midface soft tissue ptosis is often manifested by a pronounced nasojugal groove defined inferiorly by the leading edge of the ptotic malar fat pad, and typically superiorly by lower eyelid fullness from pseudoherniated orbital fat (figure 1).

Figure 1. The cheek soft tissues descend exposing fullness in the lower eyelids.

Lower eyelid surgery has primarily addressed soft tissue with lateral canthal, skin and fat procedures including transcutaneous and transconjunctival lower blepharoplasty. Even the elaborate "Madame Butterfly" procedure developed by Shorr only horizontally and vertically lengthens the surgically compromised eyelid but ultimately does not restore volume to the midface/lower eyelid complex. Dissatisfaction with the results of these techniques has spurred surgeons to explore new methods to address the scope of lower eyelid and midface abnormalities. Midface ptosis is not simply an aesthetic deficit. It also profoundly affects almost all aspects of lower eyelid reconstruction, which is enormously more difficult in the setting of a prominent globe. As soft tissue is only part of the picture, failure to understand the important role of the facial skeletal remodeling at the orbital rim has severely limited the surgeon’s ability to repair midface ptosis by soft tissue technique alone.

Early midface work relied on elevating the malar fat pad laterally or superolaterally through a facelift approach with the aim of reducing the nasolabial fold and secondarily the nasojugal groove. Other techniques attempt to elevate the midface tissues in a superiotemporal approach via a coronal or a more limited temple incision. With the adoption of the endoscopic forehead lift, techniques for superiortemporal midface lifting via an endoscopic approach were described and popularized, including the so-called coronocathoplasty. Alternative methods to accomplish a similar midface lift through an extended infracillary incision have also been described. These techniques have the virtue of offering the surgeon sites for the substantial and reliable fixation of the lifted malar soft tissue to either the temporalis fascia superotemporally or the pre-parotid fascia laterally. More recently, minimally invasive cabling techniques have been introduced. However, midface lifts that pull the malar soft tissue laterally or superolaterally result in an unnatural vector of lift. The reason for this is simple: The midface soft tissue falls in more of a vertical vector and less so in an inferior medial direction.

Some advocate the vertical elevation of the midface soft tissues to its site of origin with the goal of reestablishing a more youthful midface contour. Laxity of the osteocutaneous ligaments that support the midface soft tissues, including the orbitomalar, zygomatic, and masseteric cutaneous ligaments, appear to be important factors in the descent of the subcutaneous tissues of the midface. The orbitomalar ligament is found to extend along the orbital rim through the adipose and overlying orbicularis oculi muscle to insert on the skin. With age, the ligament relaxes and is associated with ptosis of the midface adipose. The zygomatic ligament, which helps to anchor the skin and adipose to the facial skeleton at the origin of zygomaticus major muscle also exhibits laxity with advancing age. The vertical midface lift essentially reestablishes the relationship of the malar fat to the orbital rim before the attenuation of these ligaments. Vertical elevation of the midface soft tissues to the orbital rim requires fixating mobilized suborbicularis oculi fat and midface soft tissues to the diaphanous inferior orbital arcus marginalis and orbital rim periosteal tissues. Unfortunately, the arcus marginalis is flimsy and insubstantial and lacks the strength to reliably hold the sutures needed to support the midface soft tissues while a permanent scar forms. The vertical soft tissue midface lift also does not address the involutional loss of bone projection at the orbital rim and malar face.

Other methods have also been described to address midface deficits. Cheek implants represent a classic approach to midface deficiencies. However, cheek augmentation often only serves to exaggerate the nasojugal groove. Flowers described the placement of a comma shaped silicone implant extending from the orbital rim down over the malar face. The implant is notched to accommodate the inferior orbital neurovascular bundle. More recently, a porous polyethylene implant has been used to accomplish the same augmentation. Leob originally described the arcus marginalis release with the placement of the inferior orbital fat onto the orbital rim as a vascular pedicle graft to help fill in the nasojugal groove. This surgery was popularized by Hamra and subsequently by Goldberg. However, these techniques provided only a modest improvement in the nasojugal groove and importantly it removes volume from the lower eyelid.

To address the limitations of prior techniques, since 1998, I have used hand-carved reinforced sheets of expanded polytetrafluoroethylene (e-PTFE) (W.L. Gore & Associates, Flagstaff, AZ) to compensate for the loss of bone projection at the orbital rim and maxillary face. This material is readily available in suitable sizes and thickness, and can be carved to size and shape to compensate for deficiencies in projection of the orbital rim and malar face. The material is physically strong yet pliable, so that it can be inserted with limited exposure. With the implant firmly anchored to the bone using titanium microscrews, the advanced midface soft tissues can be securely sutured to the e-PTFE implant at the orbital rim for lasting fixation. This innovation has solved two important challenges to successful vertical midface lifting: restoration of underlying orbital rim projection and reliable support and fixation of the vertically lifted midface soft tissues. Figure 2 summarizes how this surgery works.

Figure 2. A. The youthful midface. Note there is good projection of the cheek-bone and the soft tissue of the cheek is held high along the orbital rim. B. In time there is loss of bone projection at the orbital rim. The ligaments holding the cheek soft tissue to the rim also gives away causing a generalized descent of the cheek soft tissue. In many cases this exposes the inferior orbital fat producing the appearance of lower eyelid fullness. C. Dr. Steinsapir invented the vertical midface lift over a hand carved ePTFE implant. The implant helps to replace lost volume along the orbital rim and also serves as a location to sew the lifted cheek soft tissue back to it site of origin.