A keyhole middle fossa approach to large cholesterol granulomas of the petrous apex

In this article we review our surgical experience in a series of eight patients with large cholesterol granulomas of the petrous apex extending into the cerebellopontine angle.

All lesions, four primary and four recurrent, were studied with magnetic resonance imaging (MRI), and computed tomography (CT). The patients underwent pre- and postoperative audiographic testing. A keyhole middle fossa approach was used in all cases.

There was no mortality. Surgery was complicated in one case by a subgaleal hematoma and in another by a transitory increase of a preexisting facial palsy. In five cases the granuloma was totally resected, whereas in the remaining three small remnants of the pseudocapsule were left in place. At follow-up (12-90 months), three patients were asymptomatic. In the remaining five patients, trigeminal neuralgias had subsided. Palsies of the VIth cranial nerve recovered more consistently than those of the VIIth. Hearing was unchanged postoperatively. So far, there has been no clinical or radiological evidence of a recurrence.

Large cholesterol granulomas of the petrous apex can be effectively treated through a keyhole middle fossa approach. Despite its contained size the approach allows a rather large exposure of the granuloma. The resection of these lesions carries a low risk of compromising the facial or hearing function of the patient. Small remnants of the capsule, left in place to avoid potential complications, seem not to affect the long-term outcome of the patients, provided the cavity in the petrous bone is adequately ventilated.