Stereotactic and functional neurosurgery
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Stereotact Funct Neurosurg · Jan 1992
In vivo and in vitro study of the lesions produced with a computerized radiofrequency system.
For many years, radiofrequency-generated lesions have been used for the treatment of pain and abnormal movements. However, the reliability of this method has been questioned because of the variation in the size of lesions produced by the electrode at different times and temperatures. A 500-kHz radiofrequency generator with different electrodes was used to determine the size of lesions, using different time and temperature exposures. ⋯ In contrast, the use of different times at the same level of temperature showed no significant increase in most of the electrodes. There were two statistical significant time effects, for both diameter and length, with the monopolar 2-mm electrode. The use of real-time monitoring with graphic display and the feedback information provided for the computerized control of power and current allows high precision of the temperature at the electrode tip during the production of the lesion.
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Cancer pain can be successfully managed with oral or parenteral narcotics in 80% of patients, if those factors that magnify pain perception are also controlled. Pain from any source can be made worse and pain tolerance impaired by depression, regression, intolerance to stress, and/or recurrent withdrawal, all of which require attention and management. Those patients whose cancer pain is still intractable may benefit from a procedure to interrupt pain pathways. ⋯ The subarachnoid route is preferable to the epidural route because it is less likely to result in catheter failure and because much smaller doses can be used, with less systemic effect. In addition, tolerance can be managed more readily by readjustment of dose with the subarachnoid route, and there is no greater incidence of complications. Intraventricular narcotics can be considered in patients whose spinal canal does not allow catheter placement, at approximately 1/10th the spinal dose requirement.