MENINGIOMAS OF THE TENTORIAL NOTCH - SURGICAL ANATOMY AND MANAGEMENT

Twenty-five meningiomas located at the tentorial notch were surgically treated between 1978 and 1993 at the Neurosurgical Department of Nord stadt Hospital in Hannover, Germany. Nineteen meningiomas were classif ied as originating from the lateral tentorial incisura (Group I) and s ix were from the posteromedial tentorial incisura (Group II). Clinical ly, the most common symptom was trigeminal neuralgia, followed by head ache. Neuroradiologically, 64% of the meningiomas were larger than 30 x 30 mm. Further evaluation revealed signs of brainstem compression in 88% of the patients. Radical surgical removal (Simpson I and II) was achieved in 88% of the cases. There was no mortality. Follow up reveal ed that 80% of patients were able to return to their premorbid activit y. Surgical approaches to the tentorial notch included the suboccipita l retrosigmoidal or the combined subtemporal-presigmoidal approach for Group I tentorial notch meningiomas; and the supracerebellar-infraten torial or the suboccipital-transtentorial approaches for Group II meni ngiomas. Because the best surgical approach to the tentorial incisura is still a matter of debate, the anatomy of the tentorial incisura, th e clinical presentation of the patients, diagnostic indications, surgi cal findings, and follow up are discussed, with reference to the liter ature.