Evaluation of the Inferolateral Approach Combined with a Nasoseptal Flap for the Endoscopic Transsphenoidal Surgery for Cholesterol Granulomas Involving the Petrous Apex

Aim of the Study: Cholesterol granulomas involving the petrous apex are expansile, cystic lesions that usually originate within the petrous apex. Cholesterol granulomas may be clinically silent or produce headache and lesions of cranial nerves. Lateral approaches achieve drainage of the granuloma, but are associated with significant morbidity. The aim of this study is to evaluate whether lateral-seated lesions can also be managed transnasally.

Methods: Retrospective study of cases treated in our institution for a cholesterol granuloma originating in the petrous apex since 1996.

Results: Seven patients were operated on for a primary petrous apex lesion, because of headache, hearing loss, VII or VI palsy, or extensive bone destruction. Three lesions were approached medially to the ICA (petrous apex approach) with subsequent closure of the drainage, while four were operated on through a sphenopetrous approach, inferior and lateral to the second genu of the ICA, with nasoseptal flaps in all cases either for closure or for drainage. Surgery was successful in all cases but one (medial approach).

Conclusions: Primary petrous lesions originate in the deep petrous apex but may develop toward the sphenoid, at the level of the horizontal portion of the ICA. Two approaches should be considered to address the treatment of cholesterol granulomas. If the lesion is approached through the sphenoid sinus medial to the ICA, then removal will be uneasy and drainage passage may close with healing. Alternatively, the sphenopetrous approach, inferior and lateral to the ICA, provides a wide exposure and drainage.