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.