Two patients with tumors involving the superior vermis and filling the fourth ventricle were managed with a combined infratentorial supracerebellar/cerebellomedullary fissure approach. 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, suffered a protracted postoperative course characterized by suboccipital pain, torticollis, feeding difficulties and persisting hydrocephalus. Postoperative imaging showed swelling of the inferior vermis and ipsilateral hemisphere of the cerebellum with unilateral tonsillar herniation. Simultaneous compromise of the galenic and tentorial bridging veins and interruption of collateral pathways between these systems and the petrosal bridging veins, as in the combined infratentorial supracerebellar/cerebellomedullary fissure approach, may cause cerebellar venous insufficiency with venous congestion and possible venous infarction ¹⁾.