Lengthening temporalis myoplasty for facial paralysis reanimation: an objective analysis of each surgical step.

IMPORTANCE: Lengthening temporalis myoplasty is a dynamic procedure used to reanimate the middle third of the paralyzed face. Since its original description, it has been progressively modified over the years, with a reduction in the number of surgical steps. However, these modifications can decrease lengthening needed for the tendon to reach the oral commissure and upper lip without tension or overcorrection.

OBJECTIVES: To evaluate the maximal lengthening of the temporalis tendon that is possible with this technique and to assess the contribution of each surgical step to total lengthening.

DESIGN, SETTING, AND PARTICIPANTS: Cadaveric dissection study from September 16 to 23, 2013, at a tertiary referral center using 10 cadaveric hemifaces.

MAIN OUTCOMES AND MEASURES: Surgical exposure was obtained using coronal and melolabial incisions. The original surgical technique was broken down into 7 steps. Measurement of temporalis tendon lengthening relative to a fixed point was performed by a single surgeon after each surgical step using a millimeter ruler.

RESULTS: Each surgical step resulted in progressive temporalis tendon lengthening for a median maximal total lengthening of 43.5 mm. The steps that contributed most to this lengthening were coronoidotomy and intraoral temporalis tendon dissection (median, 12.0 mm), incision of temporalis fascia insertion over the orbital rim (median, 6.5 mm), and zygomatic osteotomy with dissection of masseteric fibers (median, 11.5 mm), which represent the first and last 2 steps of the procedure, respectively.

CONCLUSIONS AND RELEVANCE: Modifications of lengthening temporalis myoplasty must be considered with caution because the maximal lengthening potential can be obtained only when performing all 7 surgical steps. These modifications must be chosen appropriately based on the lengthening required for the temporalis tendon to reach the oral commissure and upper lip without tension or overcorrection.

LEVEL OF EVIDENCE: NA.