A multiinstitutional study was conducted to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. Fifty patients at five centers underwent radio-surgery performed with a single 4-mm isocenter targeted at the nerve root entry zone. Thirty-two patients had undergone prior surgery, and the mean number of procedures that had been performed was 2.8 (range 1-7). The target dose of the radiosurgery used in the current study varied from 60 to 90 Gy. The median follow-up period after radiosurgery was 18 months (range 11-36 months). Twenty-nine patients (58%) responded with excellent control (pain free), 18 (36%) obtained good control (50%-90% relief), and three (6%) experienced treatment failure. The median time to pain relief was 1 month (range 1 day-6.7 months). Responses remained consistent for up to 3 years postradiosurgery in all cases except three (6%) in which the patients had pain recurrence at 5, 7, and 10 months. At 2 years, 54% of patients were pain free and 88% had 50% to 100% relief. A maximum radiosurgical dose of 70 Gy or greater was associated with a significantly greater chance of complete pain relief (72% vs. 9%, p = 0.0003). Three patients (6%) developed increased facial paresthesia after radiosurgery, which resolved totally in one case and improved in another. No patient developed other deficits or deafferentation pain. The proximal trigeminal nerve and root entry zone, which is well defined on magnetic resonance imaging, is an appropriate anatomical target for radiosurgery. Radiosurgery using the gamma unit is an additional effective surgical approach for the management of medically or surgically refractory trigeminal neuralgia. A longer-term follow-up review is warranted.

The authors have retrospectively analyzed 840 cerebrospinal fluid shunting procedures over a 25-year period to determine the relationships between infection rates and several possible influences on infection. Two-thirds of all shunt infections occurred within 1 month of surgery. The very young and very old had higher infection rates. Infections became less prevalent over the period of the study, and mortality from infection decreased from 35% to 6%. Successive shunts (revisions) were found to have progressively higher infection rates. Ventriculoatrial and ventriculoperitoneal silicone plastic shunts had similar infection rates (11.4% and 12.0%). The uncontrolled use of prophylactic antibiotics had no effect on shunt infections. Staphylococcus epidermidis became gradually more prevalent over the period of the study, and eventually caused one-half of all infections. Where infection occurred in the presence of prophylaxis, the infectious organism was usually sensitive to the antibiotic being used. The surgeon was found to be the largest single factor in the incidence of shunt infections. A 25-fold variance in infection rates among surgeons could be related to individual experience and technique.

Standard neurosurgical management mandates prompt evacuation of all epidural hematomas to obtain a low incidence of mortality and morbidity. This dogma has recently been challenged. A number of authors have suggested that in selected cases small and moderate epidural hematomas may be managed conservatively with a normal outcome and without risk to the patient. The goal of this study was to define the clinical parameters that may aide in the management of patients with small epidural hematomas who were clinically asymptomatic at initial presentation because there was no clinical evidence of raised intracranial pressure or focal compression. A prospective study was conducted of 22 patients (17 males and five females) aged from 1 to 71 years, who had a small epidural hematoma diagnosed within 24 hours of trauma and were managed expectantly. Of these, 32% subsequently required evacuation of the epidural hematoma 1 to 10 days after the initial trauma. Analysis of the patients revealed that age, sex, Glasgow Coma Scale score, and initial size of the hematoma are not risk factors for deterioration. However, deterioration was seen in 55% of patients with a skull fracture transversing a meningeal artery, vein, or major sinus, and in 43% of those undergoing computerized tomography (CT) within 6 hours of trauma. In contrast, only 13% of patients in whom the diagnosis of a small epidural hematoma was delayed over 6 hours subsequently required evacuation of the epidural collection. Of patients with both risk factors, 71% required evacuation of the epidural hematoma. None of the patients suffered neurological sequelae attributable to this management protocol. It was concluded that patients with a small epidural hematoma, a fracture overlaying a major vessel or major sinus, and/or who are diagnosed less than 6 hours after trauma are at risk of subsequent deterioration and may require evacuation. Conversely, patients without these risk factors may be managed conservatively with repeat CT and careful neurological observation, because of the low risk of delayed deterioration.

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N-Acetylcysteine partially improved neuronal survival when administered before or after ischemia following transient cerebral ischemia (mean arterial blood pressure, 45 mm Hg) but not with a more severe ischemic insult of 10 minutes of transient cerebral ischemia with a mean arterial blood pressure of 30 mm Hg.