Hearing loss after neurosurgery. The influence of low cerebrospinal fluid pressure.

A prospective study was performed to investigate the effect of neurosurgery on hearing. Thirty-two patients underwent neurosurgery while 32 patients who had surgical procedures not involving puncture or drainage of the subdural space, served as a control group. In the neurosurgical group, a significant loss of hearing was observed in the immediate post-operative period, with recovery over one week. No average threshold shift was observed in the control group. It is suggested that following neurosurgery the mechanism of hearing loss results directly from a decrease in pressure and/or volume of the cerebrospinal fluid, which is reflected within the perilymphatic fluid, comparable to a transitory endolymphatic hydrops.