[Clinical and surgical aspects of the meningiomas of the base of the skull. III. Meningiomas of the posterior fossa].

INTRODUCTION AND OBJECTIVE: The close relationship between the meninges of the posterior fossa and major vascular structures, the possible involvement of many cranial nerves and proximity of the brainstem means that surgery of lesions in this region is difficult. Minimal differences in the site of origin of the tumour and its anatomical relations may affect the surgical approach and postoperative results. In this study three basic sites were distinguished (clival and petroclival, petrous or pontocerellar angle and foramen magnum meningiomas). Significant differences were observed in the three types.

PATIENTS AND METHODS: We present 26 successive patients whose meningiomas of the posterior fossa were resected and the results obtained.

RESULTS AND CONCLUSIONS: 1. The patients operated on included 24 women and 2 men. 2. Age was not decisive when deciding on surgery. 3. The average time between onset of symptoms and diagnosis was 14 months. 4. The petroclival meningiomas were the most difficult to excise. 5. The size of the tumours worsened the preoperative clinical situation and postoperative morbidity.