Facelift with SMAS technique and FAME

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CHAPTER 7 Facelift with SMAS technique and FAME

History

Surgery of the deep layer tissues of the face and neck is now established as a permanent part of facelift operations. There is no clear consensus as to how to treat the midface and its related nasolabial fold. Skoog introduced tightening of the midface superficial fascia and platysma muscle in the late 1960s, and Mitz and Peyronie verified the anatomy of the superficial musculoaponeurotic system (SMAS) in 1976. Surgery of the midface developed subsequent to descriptions of the retaining ligaments of the cheek, as the focus of facial rejuvenation extended to correction of the nasolabial fold. Masseteric-cutaneous and lateral zygomatic-cutaneous ligament release allowed lifting of the SMAS to correct the lower face below the zygoma. However, approaches to the prezygomatic SMAS developed in an effort to gain harmony of the upper and lower parts of the face. In this effort two different approaches are in use:

In the deep plane facelift the plane of the dissection for the lateral segment of the face is in the sub-SMAS plane, but more anterior the plane changes to become more superficial overlying the zygomatic muscles, therefore the cheek fat remains adherent to the skin flap. The composite facelift technique (this technique later modified by Hamra with the zygoorbicular dissection) continues the sub-SMAS dissection beneath the central part of the malar fat including the prezygomatic SMAS and the orbicularis oculi muscle and its fascia. Mendelson has noted that this prezygomatic space is a surgically safe space that can be entered through the lower eyelid or laterally through a space between the temporal and the zygomatic branches of the seventh nerve as is performed in the FAME (finger assisted malar elevation) technique.

Anatomy

The midcheek can be understood as part of the midface and refers to a part of the cheek medial to a line extending from the frontal process of the zygoma to the oral commissure and from the lower lid above to the nasolabial fold below. It is composed of two functionally distinct parts including the prezygomatic part over the body of the zygoma and maxilla and infrazygomatic part below, as described by Mendelson (Ch. 6). A major determinant of the shape of the midface is the underlying skeleton as it connects the orbital and oral cavities and provides a bony platform for their skeletal attachments and retaining ligaments of each muscle. The aging changes that appear in the midcheek largely reflect the effect of laxity and ptosis of the soft tissues relative to the underlying skeleton. This affects the upper face by revealing the anatomy of the orbit, with exposure of the bony orbital rim inferiorly, palpebromalar groove laterally, and nasojugal groove medially. The displaced soft tissue accentuates the nasolabial fold and reveals lower lid fat bulges. With soft tissue descent, laxity of the structures of the prezygomatic space including the orbital retaining ligament at its uppermost aspect and its roof (pars orbitale of the orbicularis oculi) are resisted by the zygomatic-cutaneous ligaments below. When visibly enlarged this area forms the clinical entity known as the malar mounds, also termed malar bags and malar crescent. It should be noted that the presence of the malar septum was described by Pessa and Garza and Pessa et al. to explain the clinical appearance of a black eye, and explain the anatomic basis of malar mounds and malar edema. Malar mounds should be distinguished from the malar fat pad. The anatomical terminology regarding this area can be somewhat confusing, as the malar fat pad is also simply known as malar fat.

Specifically, the malar fat pad is a term used to describe the subcutaneous fat of the medial cheek that exaggerates the nasolabial fold. The malar fat pad is a localized thickness of the subcutaneous panniculus adiposus (Fig. 7.1). The malar fat pad is of maximum thickness centrally in youth with a well-defined border at the nasolabial crease and less discrete border in the upper face as it blends imperceptibly into the lower lid with a gradual decrease in thickness over the prominence of the orbital rim and zygoma. The malar fat has upper, middle and lower components. The fullness of the nasolabial fold is in large part caused by the medial and inferior migration of the soft tissue medial to the zygomaticus major muscle (primarily the malar fat pad). It is triangular in shape with its base along the nasolabial crease, and its apex overlies the body of the zygoma. The malar fat pad firmly attaches to skin. It is easily separated from underlying fascia, and the malar fat pad moves forward and down perpendicular to the nasolabial crease during the aging process.

The prezygomatic space overlies the body of the zygoma and the origins of the lip elevator muscles. It extends to the posterior border of the body of the zygoma and can be accessed from the lower temporal region and lower lid. The floor is a thick layer of preperiosteal fat with an overlying thin membrane which covers the origins of the muscle bellies of the lip elevators. The upper border of the space is formed by the orbicularis retaining ligament, which separates the preseptal from the prezygomatic space and becomes confluent at the inferolateral orbital rim with the broad lateral orbital thickening that overlies the frontal process of the zygoma. The zygomatic-cutaneous neurovascular pedicle is the only structure crossing this space as Mendelson has previously elucidated. The roof of the space is the orbicularis oculi and its investing fascia, which is contiguous with the temporoparietal fascia laterally. The inferior wall of the prezygomatic space is lined by a continuation of the preperiosteal membrane and the most cephalad of the zygomatic-cutaneous ligaments as they extend between the origins of the lip elevator muscles through the subcutaneous fat to the dermis. With blunt dissection in this space, as in the FAME procedure, the smooth surface of this membrane remains intact and preperiosteal fat remains attached to the underlying facial bones. Mendelson has noted that the prezygomatic space can be entered from (1) the lower eyelid; (2) the temporal area; (3) laterally passing between the seventh nerve branches as performed with the FAME procedure to enter the prezygomatic space (Fig. 7.2).

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Fig. 7.2 Mendelson’s description of the prezygomatic space and the three access routes, lower lid, temporal and lateral.

Reproduced with permission from Mendelson BC, Muzaffar AR, Adams WP, Jr. Surgical anatomy of the midcheek and malar mounds. Plast Reconstr Surg 2002;110:885–896.