Disconnective hemispherectomy.

Hemispherectomy is a valuable procedure in the management of seizure disorders caused by unilateral hemispheric disease. Modifications to anatomical hemispherectomy have been proposed to reduce the incidence of superficial cerebral hemosiderosis and hydrocephalus while still achieving seizure control. We report on the modification of a previously described disconnective form of hemispherectomy. We used this procedure on 2 children, with the aid of stereotactic navigation in 1 of the 2 cases. This disconnection was achieved via a transventricular route with minimal cortical resection or disruption of the blood supply. Over the 20 months of follow-up, 1 patient achieved complete seizure control, and 1 patient achieved control of previously incapacitating seizures with few minor seizures persisting. Motor function and speech significantly improved in both patients. Blood loss during the two procedures was significantly less than that reported for anatomical hemispherectomy, and so far there have been no signs of postoperative complications. The hospital stay was limited to 7-14 days after surgery.

A neurocytoma and an associated lenticulostriate artery aneurysm presenting with intraventricular hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: Hemorrhage associated with central neurocytoma has been described previously, but never in association with an aneurysm originating from a feeding artery. We present the first reported case of a central neurocytoma in a patient with intraventricular hemorrhage caused by rupture of an aneurysm on a lenticulostriate artery that supplied the tumor. CLINICAL PRESENTATION: A 35-year-old man who presented with an intraventricular hemorrhage underwent magnetic resonance imaging and cerebral angiography that disclosed a right lateral intraventricular mass and a 7-mm fusiform aneurysm from a lateral lenticulostriate branch of the right middle cerebral artery. INTERVENTION: The patient underwent a contralateral transcallosal exploration and resection of the tumor, with excision of the adjacent lenticulostriate artery aneurysm. Pathological review demonstrated that the tumor was a neurocytoma. The aneurysm was discrete from the tumor but occurred on a vessel that supplied the tumor. CONCLUSION: Previous reports have demonstrated that intraventricular neurocytoma may present with tumor hemorrhage. In this case, an aneurysm separate and distinct from the tumor was the bleeding culprit, and the aneurysm was on an artery that fed into the tumor. Any such aneurysm must be identified and treated appropriately for therapy to be complete.

Radiosurgery for malignant meningioma: results in 22 patients.

OBJECT: The initial treatment of malignant meningiomas in the past has included surgical removal followed by fractionated external-beam radiotherapy. Radiosurgery has been added to the options for treatment of primary or recurrent tumors over the last 10 years. The authors report their results of using gamma knife radiosurgery (GKS) to treat 22 patients over an 8-year period. METHODS: Twenty-two patients who underwent GKS for malignant meningioma between December 1991 and May 1999 were evaluated. Three patients were treated with GKS as a boost to radiotherapy and 19 for recurrence following radiotherapy. Outcome factors including patient survival, freedom from progression, and complications were analyzed. In addition, in the recurrent group, variables such as patient age, sex, tumor location, target volume, margin dose, and maximum dose were also analyzed. Univariate and multivariate analyses were performed. Overall 5-year survival and progression-free survival estimates were 40% and 26%, respectively. Age (p < or = 0.003) and tumor volume (p < or = 0.05) were significant predictors of time to progression and survival in both univariate and multivariate analyses. Five patients (23%) developed radiation necrosis. Significant relationships between complications and treatment variables or patient characteristics could not be established. CONCLUSIONS: Tumor control following GKS is greater in patients with smaller-sized tumors (< 8 cm3) and in younger patients. Gamma knife radiosurgery can be performed to treat malignant meningioma with acceptable toxicity. The efficacy of GKS relative to other therapies for recurrent malignant meningioma as well as the value of GKS as a boost to radiotherapy will require further evaluation.

Functional MR and PET imaging of rolandic and visual cortices for neurosurgical planning.

Magnetic resonance (MR) imaging has recently been used to demonstrate physiological activation of the human brain. This development is of considerable interest to the neurosurgeon planning procedures near brain regions involving specific functions. In the present study, rolandic and visual cortices were imaged with a conventional 1.5-tesla clinical MR imager using a spoiled gradient-recalled acquisition in the steady state sequence. Two patients, one with a right frontal astrocytoma and the other with a left parietal meningioma, underwent MR imaging of rolandic cortex while performing a repetitive finger apposition task. Two patients with complex partial seizures referable to the temporal and occipital regions underwent MR imaging of visual cortex while exposed to repetitive photic stimulation (8.3 Hz). Significant signal intensity changes up to 15% between the activation and rest conditions were observed near the surgical targets at the expected anatomical location of the rolandic and visual cortices. In two of these cases activation measured by MR was compared and found similar to the activation measured at the same plane by H2(15)O positron emission tomography (PET). These results suggest that functional MR and PET techniques can be used to obtain preoperative brain mapping in individual patients considered for neurosurgical procedures.