Endoscopic Endonasal Transpterygoid Approach Using Pedicled Nasoseptal Flap for Petrous Apex Cholesterol Granuloma With Intraoperative Video, With the development of minimally invasive endoscopic surgery and image-guided navigation systems, the endoscopic endonasal approach to petrous apex lesions has become more favorable. In this case, a petrous apex cholesterol granuloma was successfully treated with an endoscopic endonasal transpterygoid approach. A navigation system was used, and a contralateral nasoseptal flap and silicone tube stent were applied to maintain the cholesterol granuloma drainage pathway. The authors describe the endoscopic endonasal transpterygoid approach using a pedicled nasoseptal flap for petrous apex cholesterol granuloma and provide an intraoperative video and a literature review. Address correspondence and reprint requests to Dong-Hyun Kim, MD, PhD, Department of Otorhinolaryngology-Head and Neck Surgery, Incheon St. Mary's Hospital, College of medicine, The Catholic University of Korea, #65 Dongsuro, Bupyung-gu, Incheon, 21431, Korea; E-mail: monolithkim@catholic.ac.kr Received 12 February, 2019 Accepted 9 March, 2019 The authors report no conflicts of interest. Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.jcraniofacialsurgery.com). © 2019 by Mutaz B. Habal, MD.