Neurosurgical venous considerations for tumors of the pineal region resected using the infratentorial supracerebellar approach.

The authors present a microsurgical technique for the resection of a heterogeneous group of pineal-region tumors and discuss the key points for successfully performing this surgery. Twenty-six consecutive patients with pineal-region tumors were resected by the senior author (H.B.) and analyzed retrospectively. For all 26 patients, the operation was conducted using the infratentorial supracerebellar (ITSC) approach in the sitting (23 patients) or Concorde (three patients) positions. Twenty-five patients had symptomatic obstructive hydrocephalus and were treated with ventricular drainage, a previously inserted ventriculoperitoneal shunt, or an endoscopic third ventriculostomy before undergoing resection of the pineal-region tumor. The gross total removal of the tumor was achieved in 23 patients and subtotal removal was achieved in three patients. The tumors were pathologically diagnosed mainly as pineocytomas (10), pilocytic astrocytomas (6), or pineal cysts (4). Twenty-five of the patients clinically improved after surgery, and there was no mortality. Two patients experienced transient postoperative neurological deterioration: one patient developed Parinaud syndrome, and one patient developed intermittent diplopia. Successful surgery and patient outcome when treating tumors of the pineal region using the ITSC approach requires: (i) preservation of the venous flow of the Galenic draining system; (ii) preservation of the thick bridging veins of the tentorial surface of the cerebellum, especially the hemispheric bridging veins; and (iii) minimizing retraction of the cerebellum during surgery to avoid adverse effects caused by both direct cerebellar compression and disturbance of the venous circulation.