Resection of intraventricular tumors via a computer-assisted volumetric stereotactic approach.

Intraventricular tumors present a major challenge for neurosurgeons because of their depth and the important structures around them. Between 1984 and 1991, we performed 60 computer-assisted volumetric stereotactic resection procedures in 58 patients with intraventricular tumors (30 patients with third ventricular tumors and 28 patients with lateral ventricular tumors). The pathological findings of the tumors were as follows: colloid cyst in 27, giant cell astrocytoma in 5, central neurocytoma in 4, pilocytic astrocytoma in 4, meningioma in 3, subependymoma in 3, metastatic tumor in 3, oligodendroglioma in 2, ependymoma in 2, and miscellaneous tumors in 5 patients. Most presenting symptoms were nonlocalized--headache or cognitive dysfunction. All third ventricular tumors were approached via a frontal trajectory, and lateral ventricular tumors were approached according to the site and shape of the lesion. Total resection was achieved in 55 procedures. Overall outcome was excellent in 45 cases, good (some deficit but independent) in 5, and poor (dependent) in 3 (memory impairment, 2 patients; visual field cut, 1 patient). Two patients (3.4%) died postoperatively (one had a postoperative thalamic hemorrhage and pulmonary embolus; one had a subdural hygroma). In follow-up, three patients died from the extension of a malignant tumor or from primary cancer. Permanent morbidity was seen in three cases (5%). The authors believe computer-assisted volumetric stereotaxis is useful in removing intraventricular tumors. This technique allows us to find a safe trajectory and to locate and separate the tumor margin from the surrounding vital structures.