Novel Use of the Leksell Gamma Frame for Stereotactic Biopsy of Posterior Fossa Lesions.

BACKGROUND: Stereotactic transcerebellar biopsies of brainstem tumors have often been reported. The Leksell frame or Cosman-Roberts-Wells frame is often used in transcerebellar approaches. However, to access lesions via the cerebellum, these frames should be secured as inferiorly on the cranium as possible, which can require exaggerated neck flexion and limit the flexible trajectory to the target. To overcome these disadvantages, we have devised a new way to use the Leksell frame for transcerebellar approaches. METHODS: The frame was fixed to the upper part of the head and arc support by attaching the frame upside down, which gives surgeons a wide operative field and permits flexible trajectory planning. RESULTS: Under local anesthesia, the surgery was performed in a sitting position. Air was observed in the target site on postoperative computed tomography and magnetic resonance imaging, which confirmed that a specimen had been successfully sampled from the site as planned. CONCLUSIONS: Our devised transcerebellar approach provided a generous operative field and a flexible trajectory, which enabled minimally invasive biopsy of a posterior fossa lesions to be performed in a short amount of time with the patient under local anesthesia.

Computerized tomography in intracranial hemorrhage.

Three hundred patients with intracranial hemorrhage were studied by computerized tomography (CT). Thalamic-ganglionic hematoma was found in 232; the mortality increased from 25% to 70% if ventricular extension occurred in this group. Lobar hematoma occurred in 45 of these patients, with a mortality of 20%, which was not influenced by ventricular extension. Seven had intraventricular bleeding only; of these, two died. In 12 patients with CT evidence of cisternal blood, angiography demonstrated aneurysms; the location of the blood predicted the location of the aneurysm in six. Multiple spontaneous intracerebral hematomas (ICHs) were visualized by CT in five patients. In 29 of 146 cases of ICH, postcontrast study showed enhancement; in 15, this was consistent with neoplasm, angioma, or aneurysm. In 14 with spontaneous ICH, ring enhancement occurred ten days to six weeks following hemorrhage.

An approach to contrast enhancement in computed tomography of the brain.

A total of 450 brain examinations were performed using computed tomography before and after intravenous infusion of methylglucamine diatrizoate 30%. In 110 cases involving a documented intracranial lesion, the scans were analyzed to determine the degree and usefulness of contrast enhancement. Enhancement was achieved in a wide variety of neoplastic and non-neoplastic lesions and was found to be of considerable help in detection of abnormality as well as in defining tumor morphology.