Endoscopic Infracochlear Approach for Drainage of Petrous Apex Cholesterol Granulomas: A Case Series

Objective: To describe the feasibility and technical nuances of a transcanal endoscopic infracochlear approach for drainage of petrous apex cholesterol granulomas. Study Design: Retrospective case review. Setting: Tertiary care university hospital. Patients: A 32-year-old man with bilateral petrous apex cholesterol granulomas and a 54-year-old man with a left-sided petrous apex granuloma each with symptoms necessitating surgical intervention. Interventions: Transcanal endoscopic infracochlear approach for drainage of the cholesterol granulomas. Main Outcome Measures: Operation efficacy, corridor size, and perioperative morbidity. Results: All three cholesterol granulomas were successful drained without violating the cochlea, jugular bulb, or carotid artery. The dimensions of the infracochlear surgical corridor measured 5 mm × 6 mm, 3.5 mm × 3.5 mm, and 6 mm × 4 mm, respectively. All corridors facilitated visualization within the cyst and allowed lyses of adhesions for additional cyst content eradication. All patients had resolution of their acute symptoms. Two of the three subjects had serviceable hearing before and after their procedures. One patient required revision surgery 2-months after their initial procedure secondary to recurrent symptoms from acute hemorrhage within the cyst cavity. The infracochlear tract in this patient was noted to be patent. Conclusions: A transcanal endoscopic infracochlear approach is feasible for the management of cholesterol granuloma. The surgical access was wide enough to introduce the endoscope into the petrous apex cavity in each case. Further studies are needed to compare the efficacy and perioperative morbidity versus the traditional postauricular transtemporal approaches.