✓ In 12 cats and two Macaca mulatta monkeys, areas of chronic focal injury were induced in the trigeminal root by implantation of a chromic suture in the nerve near its entry into the brain stem. Experimental lesions were examined histologically and electrophysiologically at 1 week, 3 weeks, and 6 weeks after surgery. At 3 weeks following implantation, lesioned nerves showed areas of focal inflammation surrounding implanted sutures with prominent demyelination of adjacent axons. A total of 497 trigeminal units were studied, 304 of which had associated demyelination of the root. In these 304 cells, two types of abnormal impulse generation from areas of focal demyelination were recorded. Reflected orthodromic action potentials and prolonged high-frequency after-discharges following short priming trains of orthodromic stimuli were observed in 23% and 4% of cells, respectively. Ectopic spike initiation from areas of focal demyelination was not dependent upon anatomical continuity of the nerve with the brain stem, was augmented by hyperventilation, and could be eliminated by the intravenous administration of diphenylhydantoin sodium. The relevance of these findings to the pathophysiological mechanisms of pain syndromes involving peripheral nerves in general and the trigeminal system in particular is discussed.
The Wada Test
Kim J. Burchiel
Kim J. Burchiel
✓ Sixty patients with trigeminal neuralgia or atypical facial pain were followed for an average of 1 year after percutaneous retrogasserian glycerol rhizolysis. The procedure was initially effective in relieving pain in 80% of the patients with typical trigeminal neuralgia and symptomatic trigeminal neuralgia secondary to multiple sclerosis. However, life-table analysis indicated that 50% of this group had persistence or recurrence of pain within 18 months after the operation. Percutaneous retrogasserian glycerol rhizolysis was ineffective in relieving atypical trigeminal neuralgia or atypical facial pain. Minor complications occurred in 23% of patients, and major morbidity was seen in 1.6%. Facial sensory loss which persisted for more than 1 month was found in 72% of patients, corneal hypesthesia occurred in 15%, and an additional 7% had corneal anesthesia. The data indicate that the success of percutaneous retrogasserian glycerol rhizolysis in relieving trigeminal neuralgia is directly related to the production of facial sensory loss.
Ashwin Viswanathan and Kim J. Burchiel
Kim J. Burchiel and Gottfried Schmer
✓ A rapid fluorometric assay technique has been utilized to assess the degree of fibrinolytic inhibition in 20 patients with ruptured intracranial aneurysms treated with epsilon-aminocaproic acid (EACA). This method quantitates the available plasminogen activity (APA) of plasma, and has proven to be a reliable means of monitoring antifibrinolytic therapy. Determination of the plasma APA also permits correlation of the level of fibrinolytic activity with putative complications of EACA therapy. Normal control plasma APA was 3.1 ± 0.7 CTA units/ml, but in patients with subarachnoid hemorrhage (SAH), pretreatment fibrinolytic activity was supranormal at 3.78 ± 0.88 CTA units/ml. During continuous intravenous administration of EACA (1.5 gm/hr) in patients with SAH, the plasma fibrinolytic activity was decreased to 0.9 ± 0.31 CTA units/ml. A case is described which exemplifies the use of this assay. In addition, an approach to monitoring antifibrinolytic therapy using the plasma APA is proposed.