Stereotactic and functional neurosurgery
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Stereotact Funct Neurosurg · Jan 1993
Comparative StudyAnalysis of parameters for epidural spinal cord stimulation. 3. Topographical distribution of paresthesiae--a preliminary analysis of 266 combinations with contacts implanted in the midcervical and midthoracic vertebral levels.
As a part of the systematic analysis of parameters involved in electrical epidural spinal cord stimulation therapy, distribution of paresthesiae in accordance with the position of contacts, as related to midline and vertebral level of contacts, was investigated. A preliminary analysis performed for 266 combinations having contacts implanted in the midcervical and low-thoracic vertebral levels showed that the topographical spread of the paresthesiae did not always cover the classical dermatomes. ⋯ This preliminary analysis suggests that more detailed studies would be worthwhile in the investigation of sensory responses to electrical stimulation of the spinal cord with epidural electrodes. Findings from such investigations could also be useful to extend our present anatomical knowledge of central and peripheral sensory neural structures.
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Stereotact Funct Neurosurg · Jan 1993
Clinical TrialExperience with 509 plate electrodes implanted epidurally from C1 to L1.
This article summarizes the experience gained with implantation of 509 plate electrodes performed by a single neurosurgeon. 350 patients were subjected to implantation of plate electrodes in the dorsal epidural space. 227 patients were implanted for chronic pain management (reflex sympathetic dystrophy, failed back syndrome/arachnoiditis, pain following spinal cord injury, nerve injury pain and other miscellaneous pain conditions), 105 patients for motor disorders (spasms/spasticity following spinal cord or head injury, cerebral palsy, multiple sclerosis, spasmodic torticollis and other miscellaneous conditions) and 18 patients for both. A total of 509 electrodes were implanted in the dorsal epidural space. ⋯ Electrode migration occurred in 1.1% of the patients and electrode breakage in 4 patients. 288 (70%) of the implanted electrodes are still being used. Technical factors relevant to the surgical implantation of plate electrodes at various levels in the spine are presented and discussed.
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Stereotact Funct Neurosurg · Jan 1993
Comparative StudyRelease of neurotransmitters in the CNS by spinal cord stimulation: survey of present state of knowledge and recent experimental studies.
Electric stimulation applied to the posterior surface of the spinal cord (SCS) is an established treatment in certain chronic pain syndromes resistant to conventional therapeutic procedures. Despite the clinical value of SCS, the mechanisms behind the efficacy of the method are largely unknown. Several neurotransmitters in the CNS (e.g. opioids, serotonin, noradrenaline, substance P, GABA), have been proposed to be involved in the pain-alleviating effect of SCS. ⋯ In the rats with PAG microdialysis, the GABA level decreased significantly following two stimulation periods, although transitional increases during SCS were noted in some animals. In the decerebrated cat, a significant release of serotonin in the dorsal horn was obtained with SCS, while the levels of the metabolite 5-HIAA were little influenced by stimulation. On the contrary, in the decerebrated preparation there was no release of substance P in the dorsal horn with SCS, although in the intact cat under barbiturate anesthesia a significant release was induced.4+ off
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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.