Introduction: Petroclival cholesterol granulomas (PCCGs) can be treated via endoscopic-assisted transnasal approaches. These approaches require access to the sphenoid sinus and visualization of the clival recess and bony landmarks to access the petrous apex (PA). In patients with a conchal sphenoid, access is guided by neuronavigation and external landmarks such as the vidian canal.

Methods: In this report, we present a case of a low-lying PCCG in a patient with a conchal sphenoid and describe the technique for nasopharyngeal access to these lesions.

Results: PRESENTATION: 55-year-old woman presented with hearing loss and tinnitus. CT and MRI showed conchal sphenoid and a large lytic expansile mass with soft tissue density centered in the right PA with bone remodeling consistent with PCCG. OPERATIVE TECHNIQUE: A standard image-guided approach including right maxillary antrostomy, uncinectomy, and middle turbinectomy was performed. The mucosa of the nasopharyngeal area and adenoid bed was then completely removed using coblation. A pedicled nasoseptal flap was harvested and tucked inside of right maxillary sinus. Using a high-speed drill with diamond bur, the transclival exposure was performed from anterior to posterior and from medial to lateral below and medial to the vidian nerve. An endoscopic Doppler probe was used throughout the surgery to identify the course of the internal carotid artery. Using cottle elevators and Kassam dissectors, the plane between clivus and paraclival soft tissues was identified, and drilling was proceeded posteriorly and laterally until the cyst contents were reached. After cyst evacuation, the diamond bur was used to extend drilling medially, superiorly, and inferiorly to enlarge the size of the tract to facilitate placement of nasoseptal flap. Successful resection was verified by postoperative CT and MRI. Postoperative nasal endoscopy verified mucosalization of the drainage tract.

Conclusions: Low-lying PCCGs can be successfully treated endoscopically via a nasopharyngeal corridor in patients presenting with conchal sphenoidal anatomy.

Patient Care: The presented operative technique can be used to successfully treat the low-lying PCCGs endoscopically via use of a nasopharyngeal corridor in patients presenting with conchal sphenoidal anatomy.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify the treatment strategies for cholesterol granuloma resection 2)Identify the important anatomical landmarks used during transclival endoscopic assisted resection of these lesions 3)Discuss, in small groups, the treatment of low-lying PCCGs in patients with a conchal sphenoidal anatomy.

References: Paluzzi A et al. Endoscopic endonasal approach to cholesterol granulomas of the petrous apex: a series of 17 patients. J Neurosurg 116:792–798, 2012