Introduction: The petrous apex is a challenging region to access. Endoscopic endonasal approaches (EEAs) to this region have been described and offer new treatment options compared to traditional open approaches that may risk auditory, vestibular and facial nerve function. We describe the outcomes of a large series of patients who underwent endoscopic endonasal surgery (EES) of the petrous apex for a variety of pathologies.

Methods: A retrospective review of the medical records was performed on EEAs for lesions involving the petrous apex between 2003 and 2014 at the University of Pittsburgh Medical Center.

Results: Ninety-eight patients underwent EES for lesions involving the petrous apex. Pathologic diagnoses included cholesterol granuloma (29), chordoma (23), chondrosarcoma (24), meningioma (18) petrous apicitis (2), and pituitary adenoma (2). All patients with cholesterol granuloma were successfully treated. Gross total resection was obtained in 20/23 (86%) chordomas, and 19/24 (79.1%) chondrosarcomas. Five percent (1/18) of meningiomas underwent gross total and 44% (8/18) had near total resection. Forty-four patients overall presented with one or more cranial neuropathies, 31 of which were abducens nerve (VI) and 17 of which improved postoperatively (38.6%). New or worsened cranial neuropathies occurred postoperatively in 19 patients (19.3%), 17 of which were cranial nerve VI. Postoperative cerebrospinal fluid leak occurred in 13 patients (13%); 6 developed meningitis. One patient had a postoperative stroke. Two patients developed perioperative posterior circulation pseudoaneurysms without apparent intraoperative vascular injury, with delayed rupture and eventual death. One patient had an intraoperative internal carotid artery injury without sequelae. All deaths and neurologic morbidity occurred in tumors.

Conclusions: A medial approach to the petrous apex via EES offers an effective treatment option with high rates of resection for select tumors. There were no facial, auditory or vestibular injuries. The most common cranial nerve injury involved the abducens nerve.

Patient Care: This research provides data that demonstrates an alternative surgical approach to the petrous apex may be favorable in terms of outcomes over other approaches.

Learning Objectives: Participants should be able to 1. Recognize that there are various surgical approaches to the petrous apex. 2. Discuss difficulties, risks, and benefits of various approaches to the petrous apex. 3. Identify patients that an endscopic endonasal approach to the petrous apex would be preferred and may provide lower risk to certain cranial nerves that are at risk with other approaches.

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