The Tightrope Facial Nerve-An Unsupported Mastoid Segment After Resection of Recidivistic Cholesteatoma.

OBJECTIVES/HYPOTHESIS: Cholesteatomas are epidermal inclusion cysts containing stratified squamous epithelium that arise in the middle ear and mastoid cavities resulting in a persistent inflammatory state. Complications include chronic otorrhea, granulation tissue, and bony erosion. Cholesteatoma growth patterns predict frequent involvement of the Fallopian canal of the facial nerve. Extensive disease may extend to the posterior and middle fossa dura, the otic capsule, the carotid artery, and the jugular bulb. Dehiscence of the Fallopian canal and direct involvement of the facial nerve epineurium by cholesteatoma are risk factors for intraoperative facial nerve injury during tympanomastoid surgery by exposing the facial nerve to mechanical trauma and inflammation during microdissection. We present two cases of recidivistic cholesteatoma with unusual medial involvement of the vertical segment of the facial nerve that resulted in an unsupported mastoid segment after resection. The outcomes from these two patients suggest that facial nerve function may be preserved despite circumferential exposure with appropriate preoperative planning and intra-operative techniques. STUDY DESIGN: Case studies. METHODS: Two patients undergoing revision tympanomastoidectomy for extensive recidivistic cholesteatoma with medial involvement of the facial nerve in the mastoid segment. In each case, the facial nerve was circumferentially exposed during the resection of the cholesteatoma. RESULTS: Normal facial nerve function after surgery was confirmed in both patients at 18 months and 6 years, respectively. CONCLUSIONS: Surgical resection of extensive cholesteatoma with medial involvement of the vertical segment of the facial nerve resulted in an unsupported mastoid segment in two patients with normal postoperative facial nerve function.