Differential Recovery in Early- and Late-Onset Delayed Facial Palsy Following Vestibular Schwannoma Resection.

Abstract

Delayed facial palsy (DFP) after resection of vestibular schwannomas (VS) is worsening of facial nerve function after an initially normal postoperative result. To characterize different types of DFP, compare recovery rates, and review of series of outcomes in patients following resection of VS. Between 2001 and 2017, 434 patients (51% female) with VS underwent resection. We categorized the patients who developed facial palsy into groups based on timing of onset after surgery, immediate facial palsy (IFP), early-onset DFP (within 48 h), and late-onset DFP (after 48 h). Introduction of facial nerve motor-evoked potentials (fMEP) in 2002 and a change of practice utilizing perioperative minocycline in 2005 allowed for historical analysis of these interventions. Mean age of study cohort was 49.1 yr (range 13-81 yr), with 19.8% developing facial palsy. The late-onset DFP group demonstrated a significantly faster recovery than the early-onset DFP group (2.8±0.5 vs 47±8 wk, P<.0001), had prolonged latency to palsy onset after initiating perioperative minocycline (7.3 vs 12.5 d, P=.001), and had a nonsignificant trend towards faster recovery from facial palsy with use of minocycline (2.6 vs 3.4 wk, P=.11). Given the timings, it is likely axonal degeneration is responsible for early-onset DFP, while demyelination and remyelination lead to faster facial nerve recovery in late-onset DFP. Reported anti-apoptotic properties of minocycline could account for the further delay in onset of DFP, and possibly reduce the rate and duration of DFP in the surgical cohort.