[Meningiomas of the posterior petrous bone: diagnostic and therapeutic aspects].

Objective: To compare the clinical and paraclinical picture and the postoperative results of meningiomas of the posterior petrous bone and to compare them with those of vestibular schwannomas (VSs) operated on by the same surgical team.

Material And Method: A retrospective study of 27 patients (23 females) operated on for meningioma of the posterior petrous bone between 1994 and 2004. These were compared with 424 patients with VS operated on between October 1994 and January 2001. All patients had a full audiovestibular workup before and after surgery. Tumours were classified according to the Desgeorges classification for meningiomas and Koss for the VS. RESULTS-DISCUSSION: For smaller tumours, facial function is better for the VS, whereas other cranial nerves are more frequently affected in the meningiomas. For larger tumours, facial function results are better for meningiomas, but other cranial nerve complications are more frequent, with a 33.3% cranial nerve V complication rate and a mortality rate of 6.6%.

Conclusion: Meningiomas of the posterior temporal bone may present clinically and radiologically like a VS, especially for intracanalar tumour and stage IV tumours. For smaller meningiomas, hearing preservation is similar to VS and could be proposed even for stage III meningiomas. On the other hand, trigeminal nerve, facial nerve, and other cranial nerve complications are more common after excision of stage I and II meningiomas.