A large midline posterior fossa medulluloblastoma and a cerebellar arteriovenous malformation with associated clot were moved with postoperative mutism. Mutism was immediate and resolved into an ataxic dysarthria with residual mild dysarthria at 3 months. The literature is reviewed, and the clinicopathological and neurophysiological data of cerebellar function in speech are discussed. Acute injury to the midportion of the cerebellum with or without dentate nuclear involvement can cause a spectrum of speech disturbances. The more widespread the injury to the midportion of the cerebellum with dentate nuclei involvement the greater the risk of developing postoperative mutism.

To characterize the temporal course of radiosurgical lesions, 19 cats were irradiated in an animal linear accelerator radiosurgical device. The animals were followed clinically and, at 3.5, 6, 12, 18, 23, 29, and 63 weeks, were studied with gadolinium-enhanced magnetic resonance (MR) imaging. They were then sacrificed after Evans blue dye perfusion, and gross pathological and histopathological studies were performed. Mild neurological deficits developed between 3.5 and 4.5 weeks, correlating with the onset of mass effect both grossly and radiographically and with the maximum amount of white matter edema on T2-weighted MR imaging and microscopic examination. Clinical improvement occurred within several weeks as these resolved. The lesions were of similar size at all time intervals. Gadolinium-enhanced MR imaging demonstrated lesions with peripheral areas of enhancement and central nonenhancing regions which correlated histologically with areas of vascular proliferation and radiation necrosis, respectively. In the early lesions at 3.5 and 6 weeks, necrosis and edema were predominant. From 12 to 29 weeks, an intermediate stage was observed, with resorption of the necrotic debris as evidenced by progressive cavitation and microglial response and by increased perilesional vascularity. At 63 weeks, resorption was still taking place, but gliosis and diminution of the vascular response were seen.

Postoperative pain control can be a major problem after selective dorsal rhizotomy for the treatment of spasticity. We report the use of epidural morphine delivered via a catheter placed at surgery for postoperative analgesia in 28 consecutive patients undergoing this procedure. Pain was well controlled using this technique, and no patients required concomitant parenteral analgesia. There were no instances of respiratory depression, wound infection, or central nervous system depression, and the patients were easily mobilized in the early postoperative period. Epidural morphine is concluded to be a safe and very efficacious method of analgesia after selective dorsal rhizotomy.

Fifteen cats were irradiated with an animal LINAC (linear accelerator) radiosurgery device. After 6 months, they were studied with gadolinium-enhanced magnetic resonance (MR) imaging, gross pathology after Evans blue perfusion, and histopathology. The lesion size was relatively constant in the cats receiving a dose of 7500, 10,000, 12,500, or 15,000 cGy to the 84% isodose line of a 1-cm collimator. The composition of the lesion correlated with dose: the lower-dose lesions were found histologically to contain areas of edema, demyelination, reactive gliosis, and vascular proliferation; the higher-dose lesions contained increasing amounts of hemorrhage and coagulative necrosis. The borders of the lesions were sharply demarcated from surrounding normal brain. Gadolinium-enhanced MR studies correlated well with areas of blood-brain barrier breakdown, as confirmed by areas of Evans blue staining. This model could serve as the basis for further studies of the biological effects of LINAC radiosurgery.

Eighteen cases of biopsy-proven pediatric diencephalic gliomas are reviewed in terms of clinical presentation, radiographic features and pathological findings. Treatment included radiation therapy (RT) in 14, chemotherapy in 4 and conservative management in 3. Actuarial survival and quality of life are analyzed. We conclude that: (1) thalamic involvment portends a poor prognosis both in terms of histology and survival, (2) beneficial effects of RT are difficult to demonstrate and (3) therapy for pediatric diencephalic gliomas should be individualized and long-term spontaneous remissions may occur.