HSC Section 3 - Trauma, Critical Care and Sleep Medicine

Sun et al

GG, and tympanic segment. For all treatment groups, a good outcome was defined as recovery to HB 1 or 2, and a poor outcome was HB 3 or worse. In the nonsurgical con- trol group (steroids only) at 7 months’ follow-up, no patients had recovered to HB 1, 4 of 11 (36%) recovered to HB 2, and 7 of 11 (64%) had only recovered to HB 3. In the cohort that underwent decompression after 14 days, 2 patients had a good outcome and 5 had a poor outcome. Of patients who underwent decompression within 14 days, 18 of 19 (94%) had a good outcome and 1 had a poor (HB 3) outcome. The benefit of surgical decompression was statistically significant ( P 5 .0001). These findings have also been corroborated in several other studies 18,35,36 and validate the following criteria for facial nerve decompression that are currently used at our institution:

Complete facial paralysis (HB 6) Presentation within 14 days of onset of paralysis Greater than 90% denervation on ENoG No voluntary EMG activity

Several previous studies have relied solely on ENoG testing to assess for surgical candidacy, choosing to forego voluntary EMG testing. 11,12,37 In these studies, no dif- ference was observed in recovery of function for patients with greater than 90% degeneration treated with either surgery or steroids alone. It is likely that some pa- tients treated with steroids alone may have had early deblocking of the nerve and would have shown positive voluntary EMG if tested. These patients should have been excluded from consideration for surgical decompression. A Cochrane Review was recently performed that found insufficient evidence to recommend surgical intervention for Bell palsy, citing the lack of a randomized controlled trial. 38 An Academy of Otolaryngology– Head and Neck Surgery clinical guidelines committee on Bell palsy could not make a recommendation on whether decompression of the facial nerve was of value in Bell palsy. This decision was made on the availability of only nonrandomized clinical trials and the equilibrium of the benefit and the harm. The committee also stated that although the data supporting surgical decompression are not strong, there may be a significant benefit for a small subset of patients who meet eligibility criteria and desire surgical management. There were major differences of opinion on the committee with regard to surgical decom- pression. This difference of opinion is based on controversy regarding the strength of evidence (C vs D level evidence). 39,40 The estimated number of patients needed to adequately power a randomized trial for surgical intervention is 716, assuming a type I error of 0.05. 12 Given this large number of required patients, the rarity of surgical candidacy, and the ethical dilemma surrounding randomization in a surgical study, it is unlikely that a randomized trial will ever occur. Middle fossa surgery is technically demanding and requires both expertise and experience on the part of the surgeon. Therefore, the decision to proceed with surgery ought to be customized to each pa- tient and surgeon, because the risk-benefit ratio is individualized to each surgeon’s training and experience. Traumatic Facial Nerve Palsy: Prognosis and Assessment of Surgical Candidacy The management of acute facial paralysis secondary to traumatic temporal bone frac- ture carries both important similarities and differences to that of Bell palsy. Traumatic facial nerve injury may likewise cause perineural edema that leads to a similar patho- physiologic cascade as Bell palsy, resulting in nerve degeneration. Surgical decom- pression is directed toward the site of neural trauma based on radiographic imaging. In longitudinal fractures, the site of disruption is frequently in the perigenicu- late region, similar to Bell. 41 However, unlike Bell palsy, trauma may also produce

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