Faculty Bibliography

A 67-year-old man with a 12-year history of trigeminal neuralgia experienced multiple fainting episodes preceded by right facial pain. One episode resulted in cardiac arrest with successful resuscitation. Pacemaker insertion prevented further episodes of syncope despite the occurrence of pain. The fainting episodes and cardiac arrest are believed to be unusual manifestations of trigeminal neuralgia

On 63 patients, we used stereotaxic surgery combined with computer tomographic (CT) technology, for reasonably safe and precise biopsy of brain lesions. Histological confirmation was possible in 97% of the cases. More recently, we have also been using the CT-guided stereotaxic technique for brachytherapy, consisting of introduction of an array of radioactive isotope seeds (192Ir). The after-loading cannulas used for the isotope seeds are now also being used for introduction of probes for localized hyperthermia of brain tumors. CT-guided stereotaxic technique is proving to be a major technological advance both diagnostically and therapeutically

A mathematical model was constructed to predict motor performance in rats for 8 weeks after spinal cord injury. The model is based on experimental data generated from an investigation of the static-load technique of inducing cord injury and was derived using multiple linear regression. The regression coefficients for weight of the injury-producing load were statistically significant (P less than 0.001), and it was found that the weight of the load contributes over 95% of the posttrauma motor deficit, whereas the time duration of the load resting on the cord contributes less than 5% to the deficit. Sex, pretrauma motor performance, and pretrauma body weight are insignificant covariates. The model may be used to establish expected motor deficits and to derive dose-response curves

Testing of potential therapies for spinal cord injury has been significantly hampered by the unavailability of a standardized, reproducible animal model with predictable outcome at a given force of injury (dose-response). The rat was selected in the development of this model in preference to larger animals for economy and availability; this permits use of large numbers of animals to increase statistical validity. In the experiments reported in this article, a static load method (weight placed gently on cord) of inducing cord injury was evaluated. A total of 198 Sprague-Dawley rats were used. Under general anesthesia, a one-level laminectomy was carried out at T-12 with the dura mater intact. Weights varying from 80 to 150 g were lowered onto the dorsal surface of the intact dura mater for durations of 0 to 300 seconds. Recovery of motor function was assessed for up to 8 weeks using two behavioral tests, a modified Tarlov scale and an inclined plane test of hind limb motor function. A statistically significant relationship was found between force of injury and motor recovery as measured by the Tarlov scale, but this did not correlate with inclined plane performance; the duration that the weight rested on the cord did not influence outcome. Pathologically, there was variation in the extent of damage for a given injury load. A semiquantitative pathological assessment of cord injury showed a statistically significant correlation between pathological score and behavioral deficit as measured by the Tarlov scale, but this did not correlate with inclined plane performance. In view of these deficiencies, the static load technique does not seem to be an ideal model for spinal cord injury research