The SMAS Flap Rhytidectomy

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With the recent advances in surgical technique, a variety of anatomically sound techniques are available to the rhytidectomy surgeon. No one operation has been created that is best for treating the aging face. The astute surgeon will understand the importance of each patients individual needs and offer techniques most appropriate to each individual patient. One such technique that lends toward a natural result is the SMAS flap rhytidectomy.

Proper incision planning and marking are crucial for creating long term patient satisfaction. Avoiding changes in hairline and visible scars is critical to a successful outcome. Patients with well hidden scars and unchanged hairlines will have more freedom with which to style their hair, leading to greater satisfaction. Often the surgeon who takes care in incision planning will garner referrals by the hairdressers and cosmeticians, who will recognize superior results.

In considering the placement of incisions, three points must be considered.

1. Maintaining the preauricular tuft of hair, including the sideburn. Each patient is different in terms of the location of the lower portion of the sideburn and the width at which it extends anteriorly from the insertion of the helical curvature. If the preauricular tuft is 1 or 2 cm below the insertion of the superior portion of the helical insertion, it may be appropriate to design an incision that curves up into the temporal hair and allows some posterior superior lifting of the hairline. The curved hairline incision, rather than a straight vertical incision is required to interrupt forces of contracture, maintain a minimally wide scar, and avoid alopecia. As long as the airline is not lifted higher than the insertion of the superior helical insertion, the patient will have no cosmetic disturbance of the area. If the sideburn is at the helical insertion preoperatively, an inferior sideburn incision is required. At no time should the incision be carried anteriorly around the sideburn tuft and along the pretemporal hairline. All scars in this area will be visible and cannot be camouflaged by the fine, severely sloped hair as it exits the skin naturally in a posterior direction. All incision should be beveled to allow hair regrowth through scars created during incision.

2. Preauricularly, the incision starts at the helical insertion and follows the apparent curvatures of the auricle itself to the helical root. The incision then goes behind the tragus about 1 to 2 mm, then exists at a junction of the earlobe with the face. In male patients, a pretragal incision is utilized so as to avoid lifting and placing hair bearing skin over the tragus. (Figure 1)

3. Postauricularly, the incision must be directed up onto the posterior aspect of the auricle, above the sulcus so that when the ear settles posteriorly and the scar heals with some contracture of the skin, the scar falls into the sulcus. At the level of the helical insertion or eminence of the concha, the incisions curve gently towards the hairline. Depending on the amount of skin laxity needed to be removed from the neckline, the incision will be directed horizontally through the hairline (for minimal skin laxity) or down along the hairline (for greater skin laxity). When advancing the postauricular skin posteriorly and superiorly, the posterior hairline can then be approximated with no step-off or other deformity. (Figure 2)

The beginning of the facelift operation requires treatment of the neck first prior to posterior shortening and suspension of the platysma muscle. In addition, treating the fatty tissues of the jowl, submentum, submandibular region and neck sets the stage for proper contouring of the neck and jaw line with treatment of the SMAS tissues. The procedure is started by making a 2 to 3 cm incision in the submental crease, followed by 0.5cm elevation of the skin to expose the subcutaneous tissue. After hemostasis is achieved, a small 3mm round liposuction cannula with three rectangular holes on one side is used to preelevate tunnels into the jowl in a radial, fanlike fashion from the left submandibular area completely to the submandibular area on the right. Once pretunneling has been accomplished, a very judicious liposuction at one atmosphere pressure of each jowl is performed so as to avoid dimpling. Symmetric and adequate liposuctioning can be accomplished by using the non-dominant hand to palpate the jowls, then lifting the tissues and excess fat into the cannula. Care should be taken to avoid turning the holes of the cannula towards the dermis to avoid dimpling. For patients with significant lipoptosis, a 5mm spatula liposuction cannula can be used in addition to the 3-mm cannula in the central neck compartment. Liposuction adds a tremendous amount to the overall initial and long-term results in facelifting with the caveat that one should under reduce the fat in any compartment rather than over remove it. Overzealous suctioning may make the ptotic submandibular gland more visible, and thus a more difficult aesthetic issue for the patient.

In most types of facelifting, further work is required to tighten the ptotic anterior platysma muscle as well as remove some subplatysmal fat in the anterior midline area. The Kelly clamp technique for submental platysmaplasty can be utilized for safe reliable results. To accomplish the Kelly clamp platysmaplasty, complete undermining of the neck skin is required. This is done with Kahn beveled facelift dissection scissors. From the submental incision the elevation is continued to the anterior part of the sternocleidomastoid bilaterally and across the cervicomental angle. Direct visualization of the remaining ptotic tissues is easily done. The forceps is used to pick up the loose anterior platysmal bands, as well as the subplastysmal fat that is redundant in the midline. A large curved Kelly clamp is then used to tighten these tissues in the anterior midline. Once tightened, creating firmness to the anterior tissues, sequential cauterization, excision, and suturing together with mattressing buried 3-0 vicryl sutures is performed. (Figure 3) This sequential excision and suturing is done from the submental crease down to and sometimes across the cervicomental angle. Excision of digastric muscle and or repositioning the hyoid muscle may be more surgical intervention than is indicated for the cosmetic surgical patient. In the very heavy neck patient, 3-0 tevdek suture is used in a figure of eight fashion to oversew the anterior platysmal plication. Thus, at this point a firm anterior corset has been created setting the stage for bilateral posterior suspension and imbrication of the platysma.

The degree of undermining of the neck skin is directly related to the amount of redundancy of skin in the neck and whether or not excisional plication of the platysma is required. The neck skin is undermined completely in order to redrape these tissues in a posterior superior fashion. The degree of laxity in the midface and concerns over viability of skin flap often dictate a lesser degree of undermining in the midcheek tissues and more attention to the underlying structures via the deep plane approach. By employing sub-SMAS and deplane techniques in the midface, much less undermining of the facial skin is required, thereby decreasing the risk of vascular compromise, particularly in smokers. The number of seromas, hematomas and other irregularities in this area are also effectively reduced as well.

After temporal, preauricular and postauricular incisions have been fashioned and beveled appropriately, skin flap elevation can be performed. Elevation of post auricular skin flap is performed first. Dissection begins deep to the hair follicles and superficial to the fascia of the sternocleidomastoid muscle, then turns more superficial until it is in the immediate subcutaneous plane. This dissection can be carried to connect to the previously elevated neck skin flaps if necessary. Using Kahn beveled facelift scissors in an advanced spread technique with the tips up, assures the surgeon that he or she is in the proper plane.

Next, attention is directed in the temporal region, where elevation is performed in the sub galeal supratemporalis fascia plane all the way to the lateral orbital rim. Dissection is continued down near the upper border of the zygomatic arch in this plane. In the event that an inferior sideburn incision as been made, a disconnected temporal incision is made to accomplish this temporal lift.

Preauricular skin elevation is then begun at the level of the helical insertion and in the subcutaneous plane. Initial dissection begins beneath the hair follicles of the sideburn and then extends out in the subcutaneous plane to the lateral orbital crow’s feet region. This can be done safely in the subcutaneous plane without risk of injury to the frontal branch of the facial nerve coursing just beneath this level of dissection. As long as one preserves the layer within the temporalis fascia in a subcutaneous plane, there is no risk to the frontal branch of the facial nerve from direct dissection. Elevation is continued approximately 3 to 4 cm in the preauricular region connecting down to the elevated neck and postauricular flaps.

Once hemostasis is obtained one can visualize all the way down below the mandibular margin into the neck. (Figure 4) An incision is then made in the SMAS extending from the inferior border of the zygomatic arch at the malar eminence diagonally down to the level of the earlobe and then continuing inferiorly 1cm in front of the anterior border of the sternocleidomastoid. One then uses a horizontal scissor dissection for the first centimeter of SMAS elevation. Further elevation of the SMAS is then performed by spreading the scissors in a more vertical fashion, directly visualizing tunnels and bridges as the dissection is carried anteriorly. Dissection is carried underneath the platysma muscle approximately 3 to 4 cm. Just above the mandibular margin, dissection is continued superficial to the masseter muscle over the premasseteric fascia. The marginal mandibular nerve is often easily visualized. Dissection is then begun in the malar region just above the zygomatic buttress in the subcutaneous plane extending just inferior to the orbicularis muscle. This dissection requires release of strong dermal attachments to the malar eminence. Some control of bleeding is often required here. Elevation is then easily extended superficial to the level of the zygomaticus muscle into the midcheek region if necessary. Individualization of the extent of midcheek SMAS undermining is important. Not all patients require full SMAS elevation of the midcheek, as has been reported for the standard deep plane facelift. Once good mobilization of the jowl has been accomplished as well as freeing and mobilization of the malar eminence, a complete elevation transition from deep to superficial to the zygomaticus muscle is not generally required. Increased safety is the result of modifying the deep plane technique, which leaves the zygomatic and buccal branches of the facial nerve in less danger of being injured.

The other modification of this technique that differs from a standard deep plane is that there is a 4 cm amount of skin elevated in addition to the SMAS, creating two separate flaps for later biplane vector suspension. At this stage the suspension of the midface and jowl tissues is accomplished by advancing the SMAS-subcutaneous skin unit in a posterior superior fashion. There is a tremendous lift and improvement of the lower and midface with the mobilization of the SMAS. This is because there are significant skin-dermal-adipose-SMAS fibrous connections. In addition, the soft tissues of the midface are elevated in continuity with this compound unit. The superior triangular portion of the SMAS is advanced and Metzenbaum scissors are used to incise the redundant preauricular portion of the SMAS. The superior slip of this SMAS is left intact and suspended to the dense preauricular temporalis fascia at the level of the helical insertion with a deep buried 0 vicryl suture. Occasionally a secondary support of one 3-0 Tevdek suture is used in the heavy cheek patient. Attention is then directed toward the overlapping platysma-SMAS at the level of the earlobe. Metzenbaum scissors are used to incise this so a posterior-inferior slip of platysma-SMAS can be suspended intact to the mastoid fascia with an 0 Vicryl suture. (Figure 5) This is literally hanging the platysma to the mastoid, creating a firm corset across the midline to the opposite side. Some redundancy of fatty tissue and SMAS overlapping the lower portions of the sternocleidomastoid are trimmed to avoid extra lumpiness in this area. 3-0 PDS sutures are then used to reinforce the platysma-SMAS unit to the posterior mastoid-sternocleidomastoid fascia. The preauricular area is also trimmed and sutured end to end with 3-0 PDS sutures to complete the SMAS imbrication. If only a small amount of jowl repositioning and posterior repositioning of the platysma muscle is required, plication of the SMAS may be the only maneuver necessary.

At this stage, the skin is easily advanced up and redraped over the auricle in a different, more posterior vector. There remains only 2 to 3 cm of undermined skin in the preauricular region. The skin from the neck is advanced to the posterior mastoid hairline region posteriorly, and then it is rotated superiorly. These three different lifting vectors achieve a similar effect as described by Baker with the tri-plane rhytidectomy. This is to assure the recreation and maintenance of the postauricular hairline and avoid step off deformity. A single suspension in the high postauricular region is performed, the hair bearing portions are reapproximated with staples, and the skin is suture with 5-0 plain interlocking catgut suture. The preauricular skin is moved in a much more posterior direction rather than superior, to avoid any undue movement of the temporal hairline. The skin is trimmed judiciously in the preauricular area, assuring that the ear lobe is cradled in a superior fashion so as to avoid Satyr’s ear deformity and a migrating scar in this region. The tragal flap is designed to be extremely redundant and pie crust sutured in a running interlocking fashion with a 5-0 plain cat gut suture. No tension is left on the tragal skin, and it is thinned judiciously to avoid over thinning and loss of viability. The closure in the temporal hair bearing portion of the skin is performed by incrementally excising the redundancy and placing one buried 3-0 vicryl suture holding the galeal suspension to the temporalis fascia. The scalp is then approximated with interrupted staples. Just prior to the conclusion of the closure, a drain is placed into the neck portion of the wound on either side to assist in the overall reduction of seromas and small hematomas. This has been demonstrated to reduce the hematoma/seroma rate significantly. A permanent 6-0 nylon is placed at the earlobe and left in for 10 days, and the remainder of the catgut sutures either dissolve, or are removed at one week. Placement of the drain also reduced the need for any kind of compressive dressing, but a light compression dressing using and abdominal dressing/combine dressing (ABD) and elastic chin strap is used for patient and family convenience. Mild compression is used in the preauricular area to prevent any fluid collection in this region. Significant compression dressings used in the past without suction drainage resulted in increased incidence of skin viability problems. Pressure dressings can create poor venous outflow and skin necrosis, which can occur from venous congestion even when arterial vascular perfusion is adequate. Slow venous flow within the flap creates an increased chance of infection further inflaming the flap and creating loss of perfusion and ultimate potential loss of viability.

After the appropriate initial follow up to assure proper healing, all patients are followed for at least one year, when postoperative results are accessed and photos are taken. Most patients continue to return for follow up for years to monitor the lasting results of their facelift. (Figure 6)

Although it has been reported that facial nerve injury can occur in 0.53 to 6% of all facelift patients, it really should not occur even with the deep plane techniques available today. In nearly two thousand patients, the only facial nerve occurrences were two temporal frontal branch paresis from stretching the nerve while elevating the temporal portion of the skin flap. These both resolved within 2-4 months. With meticulous dissection techniques in the midface region, using this modified SMAS elevation should prevent any injury to the facial nerve. Injury to the facial nerve is the most feared complication of rhytidectomy. Having a patient with paralysis could be detrimental to your long term successful practice. Choosing a facelift technique that is safe, without the risk of facial nerve injury, is highly recommended rather than being more aggressive surgically, which may risk a facial nerve injury for a small extra potential benefit in the result.

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