Pediatric sensorineural hearing loss after temporal bone radiation.

In adults, sensorineural hearing loss (SNHL) resulting from megavoltage temporal bone radiation therapy (RT) is dose dependent. A review of the literature reveals only two cases of pediatric SNHL after RT without chemotherapy. This report presents four cases of late onset, asymmetric SNHL after RT in children treated for posterior fossa tumors. The children were treated with surgical resection of the tumor, followed by RT of 50 to 54 gray and no chemotherapy. These children, without evidence of tumor recurrence, developed severe SNHL 18 to 36 months after the completion of RT. Although no definite audiometric pattern was seen, most of the patients had a predominately high frequency SNHL in the poorer hearing ear, and fluctuant hearing in the better ear, without evidence of osteoradionecrosis or otitic infection. A review of the literature suggests that injury to the outer hair cells and cochlear neurons of the basal turn of the cochlea are possible sources for the hearing loss. Pretreatment audiologic evaluation as well as a minimum of 3 years of evaluations following RT would be prudent.