Discussion: Neurotized Platysma Graft: A New Technique for Functional Reanimation of the Eye Sphincter in Longstanding Facial Paralysis.

Abstract

www.PRSJournal.com 1071e C protection is one of the highest priorities in longstanding flaccid facial paralysis patients. The inability to close the palpebral aperture secondary to a paralyzed orbicularis oculi muscle increases the risk of keratoconjunctivitis, ulcerations and, in severe cases, blindness. The orbicularis oculi muscle is a unique muscle. It is extremely thin, as it lies under the thinnest skin in the body—the upper and lower eyelids. Also, its circular shape combined with medial and lateral anchoring allows it a very distinctive sphincter action, enabling palpebral aperture closure in a cranial-to-caudal direction with minimal medialto-lateral vector. In addition, its proper tone and function are essential in periorbital aesthetics. Even when midface palsy reconstruction is optimal, patients with suboptimal aesthetic periorbital reconstruction will always carry the stigmata of facial paralysis. Static upper and lower eyelid procedures provide some corneal protection during sleeping hours but are limited during awake hours when normal blink reflex and voluntary palpebral closure are vital. Although orbicularis oculi muscle neurotization is feasible in the acute and subacute phase, longstanding palsy patients need a new neuromuscular unit. This has previously been attempted by either muscle transfers or functional muscle transplants.1 Both are imperfect. The former often suffer from lateral-to-medial action, sometimes providing closure but nearly always creating distortion. The latter demand very high technical proficiency2 and are frequently bulky. This is where the work by Drs. Nassif and Chia is unique.3 Although free muscle grafts were described as early as 1970 by Tamai et al.,4 they were inherently unreliable because of muscle ischemia, especially in thicker muscles. Nevertheless, the periorbital area needs an extremely thin muscle and, as demonstrated in regenerative peripheral nerve interface studies, small muscle grafts without axial blood supply may survive in wellvascularized wound beds and available early neurotization.5 Nassif and Chia took advantage of this approach and of the similar embryologic, histologic, architectural, and fine motor unit arrangement properties of the platysma and orbicularis oculi muscle. They transplanted two very thin platysma muscle grafts to the upper and lower eyelids after preparing the recipient bed with respective cross-facial nerve grafts. The premise is that these thin muscle grafts survive because of early vascularization and neurotization. By no means is this procedure portrayed as simple, but its beauty is its simplicity. It may seem that Nassif and Chia have provided the holy grail of periorbital reconstruction in longstanding paralyzed patients, addressing the most difficult challenges by providing a reproducible, functional, aesthetic and thin, sphincter-like reconstruction. Nevertheless, a discussion must point out limitations and encourage further development; thus, the following comments are appropriate. The methodology could be improved. The recording and reporting methods are somewhat limited and variable. Consistent before-and-after photographs and videos are paramount and are crucial for reliable retrospective data analysis. Also, despite the emphasis on the periorbita, it is important to show full facial photographs, allowing evaluation of additional facial motion, especially during forced palpebral closure, suggesting incomplete paralysis. Although the author states all patients had prolonged facial palsy, the degree of severity is impossible to assess with lack of consistent objective measures, possibly affecting outcomes by means of direct neurotization of the native muscle bed in nearly complete palsy