April 2020 HSC Section 4 - Plastic and Reconstructive Problems

Management of Flaccid Facial Paralysis

by considering the various facial aesthetic subunits in comparison with the contralat- eral (nonflaccid) hemiface. It is important to recognize that the position of structures and features of the contralateral face may also be abnormal because it is common for patients with flaccid facial paralysis to have compensatory hyperactivation within the contralateral facial musculature. It is often advantageous to divide the face into thirds during evaluation. The upper third of the face includes the forehead and brows. The forehead, where the rhytides on the flaccid versus the nonflaccid side are evaluated, is considered first. Next, the brow positions on the flaccid versus nonflaccid side are considered. The nonflaccid brow may show elevation, which should be noted in comparison with what is commonly a depressed brow on the flaccid hemiface. The middle third of the face is considered next. Upper eyelid position, lower eyelid position, and blink should all be assessed. During assessment, we ask patients to blink gently and then blink tightly to assess orbicularis oculi function. Patients with flaccid paralysis commonly have a less efficient blink, even if they can achieve full eye closure. Corneal sensation and Bell phenomenon are usually also assessed at this time. Finally, nasal base position is assessed and patients are questioned regarding any symptoms of nasal obstruction. Within the lower face, nasolabial fold depth, oral commissure position at rest, and then with smile are evaluated. The contralateral lower lip depressor anguli oris and depressor labii inferioris are frequently hyperactivated, and this should be documented. Systematic assessment of facial nerve function with standardized instruments is an indispensable part of treatment planning and outcome assessment. The eFACE in- strument has been developed and validated by Banks and colleagues. 4 This instru- ment is easy to use and has high interrater reliability among facial nerve experts. The goal of facial reanimation procedures is to facilitate improvement in both facial muscle tone and dynamic facial symmetry. Formerly, reanimation procedures primar- ily focused on restoring perioral and periocular movement; however, it has been increasingly recognized that facial muscle tone restoration is equally important and can alleviate hyperdynamic motion of the contralateral face. Most procedures devel- oped to date have focused on restoration of midface and lower face symmetry. Most of these procedures can be grouped within 2 categories: nerve substitution proced- ures and muscle transfer procedures. Nerve substitution procedures involve substitut- ing proximal motor nerve input from another cranial nerve. Conversely, muscle transfer or tendon transfer procedures use pedicled muscle flaps or free tissue transfer for reanimation of the face. When free muscle transfers are used, proximal neural input may be derived from the facial nerve (ipsilateral or contralateral) or another cranial nerve (usually masseteric and/or hypoglossal nerves). A stepwise approach that may be used for patients with flaccid facial paralysis pre- sent for less than 2 years follows ( Fig. 1 ). Duration of Facial Paralysis The key determinants in selecting a treatment strategy for flaccid facial paralysis are the duration and degree of facial weakness. The reason that duration of paralysis is so important is that it affects whether the end organs, namely the distal facial nerve branches and facial musculature, remain functional. Depending on the clinical sce- nario, patients who present less than 2 years from the onset of flaccid facial paralysis TREATMENT PLANNING

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