Gamma knife radiosurgery for arteriovenous malformations: the Furukawa experience.

The Furukawa experience treating 534 patients with cerebral arteriovenous malformations using gamma knife radiosurgery (GKRS) is summarized. By repeating radiosurgery for any residual nidus after the first GKRS, the rates of cumulative complete obliteration 7 years after this initial GKRS, according to four volume categories (< or =1, 4 > or = >1, 10 > or = > 4, > 10cm3), were 92, 89, 68 and 43%, respectively. Bleeding after GKRS was observed in 8.1% of the patients and was more frequently seen in patients with a large nidus and history of bleeding two or more times before GKRS. Cyst formation was recognized in 4.7% of patients, two thirds of which required some form of surgical intervention. Refinement of the total GKRS system contributed to earlier and more effective nidus obliteration.

Single burr hole evacuation for traumatic acute subdural hematoma of the posterior fossa in the emergency room.

A 57-year-old man and a 55-year-old man presented with acute subdural hematoma of the posterior cranial fossa due to trauma. Both were comatose preoperatively. Emergent single burr hole evacuation in the posterior cranial fossa was performed in the emergency room immediately after computed tomography. Neurological symptoms improved dramatically just after initiating the burr hole evacuation in both patients. A 57-year-old man became alert and could walk unassisted 1 month after surgery. The other could walk with assistance 4 months after surgery, although psychic disturbance resulting from cerebral contusion remained. Single burr hole evacuation in the emergency room is a useful treatment for acute subdural hematoma of the posterior cranial fossa because the procedure can be performed easily and rapidly, thus achieving reduction of intracranial pressure. Progressing neurological deterioration, reversibility of brainstem function by mannitol administration and the sign of brainstem compression and noncommunicating hydrocephalus are good indicators for this treatment.

Rapid development of an intranidal aneurysm with perifocal brain edema in an unruptured cerebral arteriovenous malformation. Case report.

The authors present the case of a 22-year-old man with an unruptured arteriovenous malformation (AVM) in which an intranidal aneurysm had grown in the course of 3 months and was complicated by perifocal brain edema. A left parietal AVM was incidentally diagnosed on magnetic resonance (MR) imaging. No aneurysms were noted on cerebral angiograms obtained simultaneously. Three months later, T2-weighted MR imaging revealed perifocal brain edema (increased signal intensity in the brain parenchyma adjacent to the nidus). An aneurysm-like signal void was demonstrated in the center of the high-signal area, but no previous hemorrhages could be detected. Angiographic studies revealed an intranidal aneurysm 4 mm in diameter projecting anterolaterally from the nidus. Surgical removal was performed without incident, and no neurological deficits or postoperative complications were observed. An MR image obtained 2 weeks postsurgery revealed complete resolution of the perifocal brain edema. To the authors' knowledge, this is the first reported case of an unruptured AVM in which an intranidal aneurysm with perifocal brain edema developed rapidly (within a few months).