A hazard of combining the infratentorial supracerebellar and the cerebellomedullary fissure approaches: Cerebellar venous insufficiency

The infratentorial supracerebellar approach is a popular technique for expo sure of lesions of the superior vermis and pineal region. The cerebellomedu llary fissure approach is enjoying increasing application as a technique fo r exposure of the fourth ventricle, Occasionally, a tumor that arises in th e quadrigeminal plate or the superior vermis grows to fill the fourth ventr icle, and for such a case a combination of the infratentorial supracerebell ar approach and the cerebellomedullary fissure approach might be considered . We report a grave hazard of this combination. Two patients with tumors in volving the superior vermis and filling the fourth ventricle were managed w ith a combined infratentorial supracerebellar/cerebellomedullary fissure ap proach. The first patient, who underwent a bilateral exposure, died on the sixth postoperative day due to massive hemorrhagic venous infarction of the cerebellum. The second patient, who was explored on one side only, suffere d a protracted postoperative course characterized by suboccipital pain, tor ticollis, feeding difficulties and persisting hydrocephalus. Postoperative imaging showed swelling of the inferior vermis and ipsilateral hemisphere o f the cerebellum with unilateral tonsillar herniation, Simultaneous comprom ise of the galenic and tentorial bridging veins and interruption of collate ral pathways between these systems and the petrosal bridging veins, as in t he combined infratentorial supracerebellar/cerebellomedullary fissure appro ach, may cause cerebellar venous insufficiency with venous congestion and p ossible venous infarction, Copyright (C) 2001 S. Karger AG, Basel.