Otopathology of Facial Nerve and Chorda Tympani Traumatic Neuromas

HYPOTHESIS: Traumatic neuromas of the facial nerve are rare lesions that can mimic other tumors of the temporal bone and might be consequential to injuries of common otologic surgeries. Literature is scarce in describing these lesions in the temporal bone. The aim of this study is to expand the histologic understanding of these lesions. BACKGROUND: Traumatic neuromas are benign proliferations of neural structures after total or partial sectioning, representing what seems to be a reparative attempt. In otologic surgeries, the facial nerve and its branch chorda tympani are at risk of iatrogenic injury that can lead to the formation of such neuromas. METHODS: A descriptive otopathology study of 14 temporal bones taken from 13 human subjects identified to have facial nerve or facial chorda tympani branch traumatic neuromas. RESULTS: We observed traumatic neuromas more commonly after stapedectomy (n = 9). Other surgeries were mastoidectomy (n = 2), cochlear implantation (n = 2), and temporal bone resection (n = 1). The chorda tympani nerve was more commonly affected than the facial nerve's main trunk. The majority of chorda tympani lesions were found in the iter chordae posterius. CONCLUSIONS: Surgical intervention can result in neuroma formation. We present a large and detailed description of histologic changes observed in posttraumatic neuromas, adding to the current knowledge of this subject.