The Degree of Facial Movement following Microvascular Muscle Transfer in Pediatric Facial Reanimation Depends on Donor Motor Nerve Axonal Density

Abstract

Therapeutic, III.

Functional results after facial reanimation in iatrogenic facial palsy

“…In the present study, functional results after facial reanimation were significantly improved for all analyzed movements, which included eyelid closure, smiling with showing teeth and maximal showing of the teeth. This concurs with previous reports in cases series describing results of facial reanimation in patients suffering from facial palsy after tumor extirpation (Fritz & Rolfes, ; Golio et al, ; Terzis & Konofaos, ), however, the present study provides objective three‐dimensional measurements, while most previous publications relied on subjective gradings or two‐dimensional assessments (e.g., measurements of mouth excursion in photographs of standardized facial movements; Snyder‐Warwick et al, ).…”

Comparison of symmetry after smile reconstruction for flaccid facial paralysis with combined fascia lata grafts and functional gracilis transfer for static suspension or gracilis transfer alone

“…In contrast, children, and younger adults without visible facial ptosis usually do not show any or only little oral asymmetry at rest. Thus, facial reanimation surgery in flaccid facial paralysis patients is challenging and the results in some aspects less predictable and often less satisfying than in the pediatric population (Snyder‐Warwick et al, ).…”

“…One reason for inferior functional and esthetic outcome in flaccid facial paralysis patients is the fact that conventional donor nerves for CFNG such as the contralateral zygomatic branch of the facial nerve carry a lower axonal load with increasing age (Hembd et al, ). In comparison, the axonal load of the masseteric motor nerve is higher than the resulting axonal load of the CFNG (Snyder‐Warwick et al, ). This higher axonal load, in turn, leads to a stronger muscle contraction (Bae et al, ; Eisenhardt et al, ; Snyder‐Warwick et al, ) which is relevant in patients with a considerable oral commissure excursion of the healthy side preoperatively.…”

“…In comparison, the axonal load of the masseteric motor nerve is higher than the resulting axonal load of the CFNG (Snyder‐Warwick et al, ). This higher axonal load, in turn, leads to a stronger muscle contraction (Bae et al, ; Eisenhardt et al, ; Snyder‐Warwick et al, ) which is relevant in patients with a considerable oral commissure excursion of the healthy side preoperatively. While the use of fascial strips can also optimize oral symmetry at rest when performing a CFNG‐innervated functional muscle transfer, the extent of oral commissure excursion upon smiling remains unpredictable in older patients.…”

“…Thus, the transferred muscle itself is not stable enough to correct the strong asymmetry permanently. Second, CFNG does not reliably result in an adequate axon count to trigger a sufficient muscle contraction for symmetric oral commissure excursion (Bae, Zuker, Manktelow, & Wade, 2006;Eisenhardt, Thiele, Stark, & Bannasch, 2013;Snyder-Warwick et al, 2015). This issue becomes more relevant in older patients because axon counts of facial nerve branches used as donor nerves for CFNG are decreasing with age (Hembd et al, 2017).…”