a fibrofatty tissue layer of collagen and elastic fibers interdispersed with fat cells and some muscle. It is continuous with the posterior portion of the frontalis muscle and the temporoparietal fascia in the upper face, the platysma muscle inferiorly in the neck, and the risorius and triangularis in the cheek. Retaining ligaments support the SMAS layer by anchoring it to the deep facial fascia and prevent its descent. Weakening of these ligaments account for the stigmata of the aged face including, formation of jowls, descent of the malar fat pad, and deepening of the nasolabial fold.

35.3 Indications

While all facelift procedures carry a certain risk, great caution is needed when a sub-SMAS dissection is undertaken. The surgeon must always be aware of the inherent danger of each technique and dissect in safe planes to avoid an inadvertent nerve injury. The safe facelift technique is particularly suitable for procedures that involved a sub-SMAS dissection that end at the anterior border of the parotid gland to avoid injury to the facial nerve branches. These include the standard SMAS facelift and the lateral SMASectomy facelift with plication.

The extended SMAS, lamellar high SMAS, deep plane, and foundation facelift procedures are more aggressive in their attempt to address the problems of midface descent and nasolabial fold deepening. Nonetheless, these extensive SMAS elevation techniques anterior to the parotid gland place the facial nerve branches in great jeopardy. Additionally, the superficial fascia tends to thin out as it is dissected more anteriorly, making the SMAS prone to tears. Particular concern is raised when the sub-SMAS dissection proceeds along the lateral border of the zygomaticus major and along the inferior border of the mandible. For these danger zones of the face, the safe technique relies on additional landmarks that can predict the location of the nerve at its most vulnerable points.

and the masseteric tuberosity are identified preoperatively. The anterior edge of the parotid gland is found along the oblique vector between these landmarks. On average, the anterior edge of the parotid gland is approximately 3.9 cm from the tragus along the transverse vector of the zygomatic arch [9] (Fig. 35.1). Subcutaneous dissection proceeds anteriorly to elevate skin posterior to the lateral canthus. As the facial nerve courses through the parotid gland, it is relatively safe and protected by the substance of the gland. Elevation of the SMAS anterior to the parotid gland as identified by the anatomic landmarks is discouraged as it places the facial nerve at greater risk to injury.

The patient is marked in the preoperative area with the surgeon’s preferred technique. Local anesthesia with sedation is my preferred anesthesia method for a facelift procedure. The facial and neck skin is infiltrated with 0.25% lidocaine with 1:100,000 epinephrine mixed with 0.25% Marcaine and 1:100,000 epinephrine. The pre and postauricular skin is incised and the skin flaps are elevated superficial to the SMAS in the anterior direction to the vertical vector of the lateral canthus. As the facial nerve courses through the parotid

35.4 Technique

Given its clinical significance, anatomic landmarks are first used to predict the location of the anterior border of the parotid gland. The inferior lateral orbital rim

Fig. 35.1 The facial nerve enters the parotid gland and splits it into superficial and deep lobes. Therefore, during the course of the facial nerve through the parotid gland, it is safe from injury. The branches of the nerve can be injured as they exit the anterior edge of the parotid gland. The anterior edge of the parotid gland can be predicted along an oblique course from the inferior lateral orbital rim (3.9 cm from the tragus) to the palpable masseteric

tuberosity (Modified from Wilhelmi et al. [9])

gland, it is relatively safe and protected by the substance of the gland during this subcutaneous dissection.

If temple skin tightening is required, the author prefers the presideburn incision to avoid widening temporal hairline to lateral canthal space, which can look unnatural. In performing a presideburn incision, incising the skin perpendicular to the hair follicles allows for hair growth through the skin. It is critical to elevate the temple skin flap in the plane superficial to the temporal parietal fascia to avoid the facial nerve frontal branches, which are found immediately beneath this fascia. The anterior incision is then continued inferiorly and curved into the natural crease toward the helical root (Fig. 35.2). The incision can be continued in the retrotragal position; however, defatting of the flap (tragal area) at inset and defatting of the tragal area will be required to recreate the thin skin normally found over the tragus. In continuing the incision around the ear lobe, a 2 mm cuff of facial skin should be preserved to avoid the pixie ear deformity. Postauricularly, the incision is placed 2 mm posterior to the postauricular sulcus. As this incision is extended postauricularly, the superior margin of the postauricular incision can be made directly posterior to the helical root to minimize risk of postauricular skin flap necrosis (Fig. 35.3). When continuing the postauricular incision into the hairline the scar can be hidden better if the incision is made into the hair in a lazy S fashion, initially along the hairline and then horizontally

into the junction between the thick and thin hair, again perpendicular to the hair follicles. When platysmal resection is anticipated the cervical skin elevation can be completed with the additional exposure through a submental incision. This submental incision should be placed 5 mm posterior to the natural submental crease to avoid creation of witches chin or exaggerated indentation in the crease with resultant protruding chin pad.

Then the SMAS is marked inferiorly along the zygomatic arch 3.9 cm from the tragus and along the oblique vector in the direction of the masseteric tuberosity, corresponding to the anterior edge of the parotid, to avoid injury to the midfacial branches of the facial nerve, where they exit the parotid (Fig. 35.4). Then, the SMAS is infiltrated with local anesthesia along the proposed plane of dissection. The SMAS elevation is performed in the posterior to anterior direction starting at the tragus. The SMAS is then elevated along the inferior border of the Zygomatic Arch to avoid the Facial nerve frontal branches. Above the zygomatic arch the frontal branches become more superficial and at risk for injury. The SMAS is elevated anteriorly and inferiorly up to the oblique vector corresponding to the parotid anterior edge. Cessation of SMAS elevation at the 3.9 cm location reduces the risk for facial nerve injury to the midfacial nerve branches that course through the parotid gland. SMAS dissection continued past the anterior edge of the parotid gland risks injury

Fig. 35.2 (a) The anterior incision is continued inferiorly and curved into the natural crease toward the helical root. The incision can be continued in the retrotragal position; however, defatting of the flap (tragal area) at inset and defatting of the tragal

area will be required to recreate the thin skin normally found over the tragus. (b) In continuing the incision around the ear lobe, a 2 mm cuff of facial skin should be preserved to avoid the pixie ear deformity

Fig. 35.3 Postauricularly, the incision is placed 2 mm posterior to the postauricular sulcus. As this incision is extended postauricularly, the superior margin of the postauricular incision can be made directly posterior to the helical root to minimize risk of postauricular skin flap necrosis. When continuing the postauricular incision into the hairline the scar can be hidden better if the incision is made into the hair in a lazy S fashion, initially along the hairline and then horizontally into the junction between the thick and thin hair, again perpendicular to the hair follicles

Fig. 35.4 Then the SMAS is marked inferiorly along the zygomatic arch 3.9 cm from the tragus and along the oblique vector in the direction of the masseteric tuberosity, corresponding to the anterior edge of the parotid, to avoid injury to the midfacial branches of the facial nerve, where they exit the parotid

to the facial nerve midfacial branches. Another landmark for cessation of SMAS elevation is the SMAS fat pad, found along the superior aspect of the anterior parotid edge. The SMAS is elevated in continuity with

the platysma. SMAS elevation should not be performed in the area where the facial artery courses over the mandible, as the marginal mandibular facial nerve branches become superficial in this location and are at risk. Then the SMAS is advanced posteriorly and superiorly and plicated from zygomatic arch to the mastoid area. The skin is then carefully pulled along a horizontal vector posteriorly. Initial sutures are placed at the cephaloauricular sulcus and anterior superior postauricular region. The excess skin is removed carefully to avoid excessive tension on the wound edges, which could result in widened scars. Drains are not routinely used. The sutures can be removed within a week. Pressure garment is encouraged for 2 weeks.

Modifications to the traditional SMAS dissection attempt to improve the nasolabial prominence by elevation of the malar soft tissue ptosis. In the extended SMAS facelift, it is advocated to release SMAS fibers spanning the upper lateral border of the zygomatic major muscle followed by continued dissection medial to this muscle. Release and subsequent medial dissection increases the risk of facial nerve injury, particularly the zygomatic branch fibers to the orbicularis oculi muscle. Again, bony anatomic landmarks are used to predict the location of this danger zone. The upper extent of the lateral border of the zygomaticus major muscle is located in relation to an oblique line extending from the mental protuberance to the inferior lateral orbital rim. On average, the lateral border of the zygomaticus major muscle is 0.4 cm lateral and parallel to this line.

Techniques attempting to release the SMAS anterior to the parotid gland along the mandibular border place the marginal mandibular at great risk. During a subSMAS cheek dissection, the marginal mandibular branch can be found in the buccal space, emerging from the parotid gland and coursing along the inferior border of the mandible. The most vulnerable point is the region where the nerve courses over the anterior facial artery and vein. Since the marginal branch is just deep to a thin platysma-SMAS layer, any effort to control bleeding from an injured facial vessel can cause irreversible damage to the nerve. We advocate the use of distance ratios to predict the location of the nerve as it crosses over the facial artery. The distance between the masseteric tuberosity and the mental protuberance is measured. At approximately one-fourth of the distance from the masseteric tuberosity, the marginal mandibular branch is predicted to cross the facial artery on its way to innervate the depressor anguli oris and mentalis muscles.

The goal of the safe facelift is to provide the patient with a natural look postoperatively and to avoid the appearance of an operated face (Fig. 35.5).

35.5 Discussion

Biochemical studies have demonstrated an advantage to the addition of SMAS tightening to the facelift procedure. Har-Shai [10] studied the viscoelastic properties of the SMAS and found that it had less slackening

effect compared with preauricular skin, which would explain the lasting effect of with the use of the SMAS. Several different SMAS tightening procedures have been described. There has certainly been considerable controversy over which tightening procedure provides the best aesthetic outcome. A prospective study compared the lateral, standard, and extended SMAS and composite rhytidectomies and found no discernable difference between these procedures. Although most plastic surgeons agree that treatment of the SMAS should be a component of the facelift, there is still a controversy over which is the best operation.