Surrogate Markers for Facial Nerve Dehiscence in Cholesteatoma Surgery

Background: Lateral semi-circular canal dehiscence (LSCCD) and facial nerve dehiscence (FND) may increase the risk of dead ear and facial paralysis in cholesteatoma surgery. While CT scanning may show LSCCD, disease extent and ossicular erosion, FND is difficult to assess via this modality. Our study aims to establish the correlation between the factors which can be assessed on CT and FND. We compared social deprivation levels to determine any predictive value on FND.

Methods: Consecutive patients undergoing surgery for cholesteatoma by one otologist from 2009 to 2014 were included.

Results: Of 132 patients included in the study, FND was noted in 29 (22%). There was positive correlation between FND and ossicular chain erosion, Pearson correlation=0.289(p=0.001), LSCCD 0.087 (p=0.322) and extent of cholesteatoma 0.077 (p=0.382). Deprivation index scores followed normal distributions.

Conclusions: There is positive correlation between FND and cholesteatoma extent, LSCCD and ossicular erosion. The correlation with ossicular erosion is statistically significant thus helping to predict FND with pre-operative CT scans. Socioeconomic status does not predict FND.