Hearing loss following ventriculoperitoneal shunt in communicating hydrocephalus patients: a pilot study.

OBJECTIVES/HYPOTHESIS Hearing loss can be associated with a decrease in cerebrospinal fluid (CSF) pressure because changes in CSF pressure induce changes in perilymph pressure. Hearing loss after neurosurgical procedures have been reported, but clinical information on hearing loss after the placement of ventriculoperitoneal (VP) shunts, the most commonly used CSF shunt for hydrocephalus patients, is limited. This study is aimed to show the relationship between VP shunt and hearing loss. STUDY DESIGN Prospective study. METHODS Pure tone threshold and electrocochleography were preoperatively performed in nine patients (18 ears) undergoing elective VP shunt placement. Five-day and 1-month post-shunt placement hearing thresholds were compared with baseline data. A correlation analysis was conducted between the threshold and summating potential/action potential (SP/AP) ratio changes at 5 days and 1 month after shunt placement. Cochlear aqueduct dimensions measured by high-resolution CT were compared between ears with and without hearing loss. RESULTS About 40% of subject ears showed hearing loss with a threshold elevation of at least 15 dB in one or more frequencies. After VP shunt placement, the mean threshold of all ears showed a significant increase in most frequencies and the pure tone average. The change in the SP/AP ratios was significantly correlated with the change in the pure tone average at both 5 days and 1 month after shunt placement. Cochlear aqueduct dimensions were not correlated with hearing loss occurrence. CONCLUSIONS Hearing thresholds may increase following VP shunt placement, possibly due to secondary endolymphatic hydrops.