Lésions de la région pinéale et falco-tentorielle. Abord occipito-pariétal en trois-quarts ventral avec volet infra-sagittal [Lesions of the pineal and tentorial region. Occipito-parietal approach in three-quarter prone position with infrasagittal craniotomy].

Abstract

Surgical treatment of pineal-tentorial region lesions remains a challenge. The difficulty in approaching the pineal region can be verified with the number of operative plans that have been proposed to reach this area: transcallosal, occipital transtentorial, infratentorial supracerebellar approaches and sitting, prone or Concorde positions. This emphasizes the surgeon's dissatisfaction with the surgical techniques described. Recently, a three-quarter prone position with the bone flap placed under the midline has been described (1, 3, 8). We have decided to test this approach that we have slightly modified and we report our results on 13 cases: 2 arachnoid cysts, 3 vascular malformations and 8 tumors (3 brainstem gliomas, 2 dysgerminomas, 1 quadrigeminal plate metastasis and 1 meningioma plus 1 metastasis of the falx). Keeping the table in a horizontal plane, risks of air embolus are eliminated. Using the natural effect of gravity, traction on the occipital lobe is no more necessary and hemianopsia no more occurs. We recommand the parieto-occipital route which is the shortest way to reach epiphysis and falco-tentorial notch. We confirm the results of american colleagues (1, 3, 8, 15) and we advise to use this approach which seems to us the best way to treat pineal-tentorial lesions