Endoscopic Trans-sphenoidal Transclival Approach to Cholesterol Granuloma of the Petrous Apex

Abstract

Cholesterol granulomas of the petrous apex present a challenge to the surgeon owing to their complicated anatomic position in close proximity to critical neural and vascular structures. Many approaches have been described, with recent descriptions using advances in endoscopes and image-guidance systems to refine the trans-sphenoidal approach first performed by Montgomery in 1977. The trans-sphenoidal approach has been described for lesions located in the medial portion of the petrous apex adjacent to the sphenoid sinus. We present a 16-year-old boy who presented with recurrence of a left-sided petrous apex cholesterol granuloma treated initially 2 years prior with a lateral skull base approach. Computed tomography and magnetic resonance imaging revealed a cholesterol granuloma involving the left middle cranial fossa and the left petrous apex, entirely posterior to the sphenoid and abutting the posterolateral surface of the clivus. We accomplished complete drainage with an endoscopic endonasal trans-sphenoidal transclival approach without the need for mobilization of the petrous carotid. The number of surgeries available to approach the petrous apex testifies to its enigmatic location. Endoscopic approaches continue to evolve, along with the skills and instruments powering them. The choice of appropriate surgery should depend on the surgeon's experience, anatomy of the lesion, and morbidity to the patient.