Endoscopic Endonasal approach to Petrous Apex Cholesterol Granulomas: Outcomes of a Series of 28 Patients

Introduction: The endoscopic endonasal approach (EEA) to the petrous apex provides an alternative approach for the treatment of petrous apex cholesterol granulomas. Two principal concerns for this approach are maintenance of the drainage pathway with a circumferential deepithelized wound and avoidance of complications. This study reports the outcomes of a series of patients treated with this approach and different means of managing the drainage pathway.

Method: Patients diagnosed with petrous apex cholesterol granulomas were identified from the University of Pittsburgh Medical Center's Center for Cranial Base Surgery database which contains over 2,700 patients that underwent an EEA procedure for a skull base lesion between 1999 and 2014. A retrospective chart review was performed on identified patients.

Results: A total of 28 patients underwent a total of 31 EEAs for cholesterol granuloma. Of the 28 patients, 18 (64%) patients were males, 10 (36%) were females. Of the 31 approaches, 21 (68%) utilized a combined transpterygoid transclival approach and 10 (32%) required an infrapetrous extension. A simple marsupialization was used in 4 (13%), a silastic stent in 13 (42%), and mucosal lining of the posterior aspect of the drainage tract in 14 (45%). Mucosal coverage was accomplished with a free mucosal graft in three (10%), a miniflap in seven (23%), a combined free graft and silastic stent in three (10%), and combined miniflap and stent in one (3%). All patients had partial or complete resolution of symptoms postoperatively. Complications included intraoperative CSF leak in three (10%), transient postoperative sixth nerve paresis in two (6%), recurrent sinusitis in two (6%), meningitis in one (3%), new onset eustachian tube dysfunction in one (3%), and epistaxis in one (3%). Two patients had to return to the OR for stent removal under general anesthesia. No patients had a postoperative CSF leak, internal carotid artery injury, or dry eye syndrome. Four patients were diagnosed with recurrence of whom three underwent revision endoscopic endonasal surgery. Of the four recurrences, two had a simple marsupialization and two had silastic stent alone at the initial procedure. No patients with mucosal lining of the drainage tract developed recurrence. The majority of patients were discharged on postoperative days 1 or 2 for a mean length of stay of 1.8 days.

Conclusion: EEA is a safe and effective means of approaching the petrous apex. In this series, partial coverage of the drainage tract with mucosa resulted in lower rates of stenosis and recurrence. Silastic stenting did not improve rates of patency.