Abstract
Objective This study is to establish predictors of facial paralysis and auditory morbidity
secondary to facial schwannomas by assimilating individualized patient data from the
literature.
Design A systematic review of the literature was conducted for studies regarding facial
schwannomas. Studies were only included if they presented patient level data, House–Brackmann
grades, and tumor location by facial nerve segment. Odds ratios (OR) were estimated
using generalized linear mixed models.
Main Outcome Measures Facial weakness and hearing loss.
Results Data from 504 patients were collected from 32 studies. The geniculate ganglion was
the most common facial nerve segment involved (39.3%). A greater number of facial
nerve segments involved was positively associated with both facial weakness and hearing
loss, whereas tumor diameter did not correlate with either morbidity. Intratemporal
involvement was associated with higher odds of facial weakness (OR = 4.78, p < 0.001), intradural involvement was negatively associated with facial weakness (OR = 0.56,
p = 0.004), and extratemporal involvement was not a predictor of facial weakness (OR = 0.68,
p = 0.27). The odds of hearing loss increased with more proximal location of the tumor
(intradural: OR = 3.26, p < 0.001; intratemporal: OR = 0.60, p = 0.14; extratemporal: OR = 0.27, p = 0.01).
Conclusion The most important factors associated with facial weakness and hearing loss are tumor
location and the number of facial nerve segments involved. An understanding of the
factors that contribute most heavily to the natural morbidity can help guide the appropriate
timing and type of intervention in future cases of facial schwannoma.
Keywords
facial schwannoma - facial nerve - facial palsy - hearing loss - parotid neoplasm
- temporal bone neoplasm - cerebellopontine angle neoplasm
