Prognostic factors for the incidence and recovery of delayed facial nerve palsy after vestibular schwannoma resection Clinical article

Object. Preservation of facial nerve function in vestibular schwannoma (VS) resections remains a significant operative challenge. Delayed facial palsy (DFP) is one specific challenge yet to be fully elucidated. The aim of this study was to evaluate DFP among VS resection cases to identify significant prognostic factors associated with its incidence and clinical recovery. Methods. This investigation involves a retrospective review of 104 cases of VS resection that occurred between December 2005 and May 2007. Patients who developed DFP were compared with patients exhibiting no facial palsy postoperatively with regard to surgical approach, severity and day of palsy onset, tumor size, intraoperative facial nerve monitoring, and postoperative recovery and treatment. Patients who demonstrated immediate facial palsy (IFP) following VS resection were also analyzed. Furthermore, specific analyses were performed in 2 distinct DFP patient groups: those who developed DFP after postoperative Day 3 ("late onset DFP"), and those whose palsy worsened after initial DFP identification ("deteriorators"). Results. Of the 104 patients who underwent VS resection, 25.0% developed DFP and 8.6% demonstrated IFP postoperatively. The DFP group did not differ significantly in any measure when compared with patients with no postoperative facial palsy. However, patients with DFP presented with significantly smaller tumor sizes than patients with IFP. This IFP group averaged significantly smaller intraoperative facial nerve responses than patients without facial palsy, and larger tumor sizes than both the DFP and no facial palsy groups. Within the DFP group, patients with late onset DFP showed diminished intraoperative facial nerve responses when compared with the total DFP patient population. In total, 25 (96.2%) of 26 patients with DFP and 7 (77.8%) of 9 patients with IFP recovered to normal or near-normal facial function (House-Brackmann Grade I or II) at longest clinical follow-up. Conclusions. Although patients with DFP did not exhibit any distinguishable characteristics when compared with patients without postoperative facial palsy, our analysis identified significant differences in patients with palsy presenting immediately postoperatively. Further study of patients with DFP should be undertaken to predict its incidence following VS resection. (DO!: 10.3171/2010.5.JNS091854)