Endoscopic Approach to Petrous Apex: Clinical Series

Background The petrous apex is arguably the most anatomically complex region of the skull base. The region's intimate relationships with the internal carotid artery (ICA) and audiovestibular apparatus render surgical access to the petrous apex exceedingly difficult. Traditional transcranial techniques are technically demanding and associated with a significant risk of postoperative morbidity. The endoscopic endonasal approach (EEA) to the petrous apex was recently described. EEA affords minimally invasive access to lesions of the petrous apex. We present our experience with EEA in the management of petrous apex lesions at two university medical centers in the United States and Chile.

Objectives To assess the outcomes and complications of our experience with EEA in a subset of patients with petrous apex lesions managed at two international skull base referral centers.

Methods Cases of petrous apex lesions managed with EEA at two skull base referral centers in the United States and Chile were retrospectively reviewed (2015–2017). Variables including patient sex, age, clinical signs at presentation, comorbidities, and histopathological diagnosis, and postoperative status were abstracted and analyzed. Outcome measures included perioperative morbidity, complications, and resolution of symptoms.

Results Eleven patients with petrous apex lesions managed with EEA were identified (5 cholesterol granulomas, 1 cholesteatoma, 1 chondrosarcoma, 1 plasmacytoma, 1 petrous abscess, 1 retention cyst, 1 metastatic disease). Single interventions were performed in 10 of 11 cases (90.9%). One patient underwent a second intervention for effective disease management. At last follow-up, partial resolution of symptoms was observed in 4 of 11 (36.4%) cases; complete resolution of symptoms was observed in the remainder (63.6%). Complications were reported in two patients (18%). Cerebrospinal fluid fistula and cranial nerve palsies occurred in 1 of 11 (9%) and 1 of 11 (9%) cases, respectively. Postoperative mortality from metastatic disease was reported in a single patient (0.09%).

Conclusion EEA affords safe and direct minimally invasive access to the petrous apex, entirely avoiding the need for external incision and temporal lobe retraction and, thus, serves as an effective alternative to manage highly selected cases. Further studies are necessary to determine the precise role of EEA in the management of petrous apex lesions. International multi-institutional collaborations among skull base centers are essential to bridge the gaps at all levels of skull base surgical care and should be the goal of every experienced institution.