Total Composite Flap Facelift and the Deep-Plane Transition Zone: A Critical Consideration in SMAS-Release Midface Lifting

Abstract

Background: Recent anatomic studies suggest the superficial musculoaponeurotic system (SMAS) layer attenuates in the midface. This led the author to switch from a bilamellar high SMAS dissection to a "total composite flap" technique, preserving skin and SMAS/platysma as one layer in a critical "deep-plane transition zone" (DTZ) lateral to the zygomaticus major muscle. This allows traction on the SMAS to translate to the malar fat pad via a "cantilever bridge" effect, which is lost when skin is undermined in the DTZ.

Objectives: This paper attempts to answer the question of whether the composite flap or bilamellar technique better lifts the midface, comparing groups where the DTZ was undermined: (1) only at a sub-SMAS level; or (2) at both subcutaneous and sub-SMAS levels.

Methods: Thirty-five patients underwent bilamellar facelifts with skin and SMAS separated in the DTZ. Midfacial elevation was measured using size-matched preoperative and 18-month (average) postoperative photographs for the 70 hemi-midfaces. The same analysis was done for 35 patients undergoing total composite flap facelift, maintaining skin and SMAS as one layer in the DTZ. The two groups were compared.

Results: In the bilamellar group, the mean percentage of midfacial elevation at 18 months postoperative was 5.5% (range, 0.0%-17.8%). In the composite flap group, the percentage was 11.7% (range, 0.1%-32.3%). The difference was statistically significant.

Conclusions: Maintaining skin-SMAS attachments in the DTZ improves midface elevation during SMAS facelifting, exploiting a "cantilever bridge" effect of the skin transferring traction on the SMAS to the malar fat pad.

Figure 1.

Deep-plane transition zone (DTZ). The borders of the trapezoidal-shaped DTZ are: laterally, an oblique line starting 4.5 cm anterior to the tragus and ending 2.5 cm antero-inferior to the ear lobule, even with the oral commissure; superiorly, the midpoint of the zygomatic arch; medially, the zygomaticus major muscle with an anterior bend over the prezygomatic space; and inferiorly, the transverse line even with the oral commissure. As shown in Figure 5, the deep-plane dissection continues inferior to this line, across the jawline and into the neck, but the area above it is the portion relevant to midface elevation.

Figure 2.

SMAS layer attenuation. The thinning of the SMAS as it courses towards the zygomaticus major muscle is shown.

Figure 3.

SMAS strength zones. The elastic modulus and ultimate strength of the upper lateral SMAS is distinctly greater than that of the more medial and inferior SMAS, divided into two zones, I (stronger) and II (weaker). Adapted from Hu et al.

Figure 4.

SMAS strength zones with DTZ overlaid. The DTZ overlaps the weaker medial SMAS in the midface. This ensures that the flap in this area is structurally and functionally adequate to transmit tension into the midface.

Figure 5.

Areas of undermining for the author's technique. Limits of skin (in blue) and SMAS (in red) undermining for the author's technique, with the DTZ entirely within the red area of composite-flap undermining. The area of undermining medial to the zygomaticus major muscle is subcutaneous by definition, since there is no SMAS layer in this zone. (The premasseteric dissection joins an extended subplatysmal dissection into the neck. Platysma, but not skin, is undermined towards the midline of the neck, preserving cervical facial nerve branches. This continuation of the facial composite flap into the neck generates a very smooth, youthful jaw and neckline, while elevating ptotic submandibular glands and avoiding irregularities characteristic of subcutaneous neck dissection.)

Figure 6.

(A) This diagram of an axial section at the level of the nasal base illustrates what happens in a dissection where the skin and SMAS are separated in the DTZ. This dissection transects the first support of the “cantilever bridge” that transmits lateral SMAS tension into the malar fat pad. The image shows the skin (“A”) being separated from the SMAS (“B”), and this separation extends (as it does in the traditional bilamellar SMAS lifting techniques) medially, to beyond the location of the zygomaticus muscles. Traction applied to the SMAS separates it farther from the malar fat pad because all durable attachments, including retaining ligaments (“C”), between it and the SMAS have been severed by the subcutaneous dissection. Although the main vector of pull tends to be more vertical, the lateral vector is shown for purposes of this illustration. (B) In contrast, the second diagram of an axial section where the skin (“A”) and SMAS (“B”) have been left attached to one another in the DTZ (red-shaded area) illustrates the “cantilever bridge effect” of the skin elevating the malar fat pad up as the SMAS is elevated. Traction on the SMAS transmits via the skin to the malar fat pad, which shifts superolaterally (its former location being shown by the dotted outline). Retaining ligaments (“C”) are left intact at the subcutaneous level. Although not specifically shown in this diagram, retaining ligaments are separated at the sub-SMAS level in both composite flap and bilamellar techniques.

Figure 7.

Half-and-half photograph showing a mirror image of the right (A) and left (B) hemiface of a 54-year-old woman before and 12 months after total composite flap facelift, and reference marks used for measurements. The midpupil to lid/cheek junction was measured. This measuring technique is similar to that recommended by Hamra as the most objective means available of assessing midface elevation.

Figure 8.

Total composite flap facelift dissection as demonstrated on a 52-year-old woman. Upper and lower key masseteric ligaments, as well as zygomatic ligaments, have been fully released. At upper right are the prezygomatic space and the origin of the zygomaticus major muscle (white arrow). Orbicularis oculi fibers have been elevated with the composite flap, and are visible being retracted above zygomaticus major. Facial nerve branches are visible and are marked by black arrows. Left to right, these branches are: marginal mandibular branch, lower buccal trunk, upper buccal trunk, zygomatic branch, and zygomatic branch to orbicularis oculi (coursing over the zygomaticus major muscle).

Figure 9.

Example of a bilamellar facelift (early group). This 56-year-old woman complained of general facial aging and said that people thought she looked angry even when she was not. On examination she had moderate midfacial deep tissue ptosis, deepening nasolabial folds, and jowling, as well as platysmal laxity. (A, C) Preoperative and (B, D) 24 month postoperative photographs of a facelift with skin and SMAS raised as separate flaps in the DTZ and midline corset platysmaplasty. She also underwent endoscopic browlift and upper blepharoplasty. The elevation of midfacial highlights in this case was negligible.

Figure 10.

Example of a total composite flap facelift (later group). This 54-year-old woman (same patient featured in Figure 7) complained of looking tired and droopy. Examination showed severe ptosis of mid- and lower deep facial tissues, platysmal laxity, and upper and lower lid blepharochalasis. (A, C) Preoperative and (B, D) 14 month postoperative photographs of a facelift with skin and SMAS left attached in the DTZ. She also underwent midline corset platysmaplasty with digastric shaving and partial inferior platysmal transection, upper blepharoplasty, and transconjunctival lower blepharoplasty with fat repositioning. Elevation of midfacial highlights was significant in this case (16% on right and 10% on left). The incision is not visible and the jawline is restored, without excessive thinning of the tissues which can occur with lateral neck skin undermining.

Figure 11.

(A) Incision diagram for primary total composite flap facelift demonstrated on a 57-year-old woman. The incision begins in the temporal hair and angles posteriorly just above the helical root. It then curves downward and makes a sharp posterior angle just above the tragus, then continues just behind the crest of the tragus, turning acutely supero-anterior at the base of the tragus and then following the contour of the intertragal incisure to the upper ear lobe, with a notch just superior to the lobe and then around it. (The postauricular incision runs up the postauricular sulcus and just within the posterior hairline, acutely beveled so that hair grows through the hairless edge of the flap as it heals.) (B) Preauricular incision design for secondary total composite facelift demonstrated on a 60-year-old woman. To avoid raising the sideburn, the incision begins behind the anterior 1/3 of the sideburn with w-plasties which course under the sideburn as depicted. The remainder of the incision is the same as in Figure 11A.

Figure 12.

(A) Preoperative photograph of this 57-year-old woman's ear (same patient in Figure 11A). (B) Fifteen-month postoperative photograph after primary total composite flap facelift, showing preservation of the tragal contours and the intertragal incisure below the tragus. The incision is essentially invisible even on close inspection.

Figure 13.

(A) Preoperative photograph of this 60-year-old woman's ear (same patient in Figure 11B). The scar from a previous facelift (done by another surgeon) is visible and shows a truncated tragus as well as a vertical line over the intertragal incisure. The ear lobe is also attached at the scar. (B) Thirteen-month postoperative photograph after secondary total composite flap facelift. The sideburn has not been raised, and the tragal contours have been re-established. The intertragal incisure has been restored. The ear lobe now hangs normally.