Applied neurophysiology
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Applied neurophysiology · Jan 1981
Comparative StudyExamination of possible mechanisms by which stimulation of the spinal cord in man relieves pain.
Stimulation of the spinal cord may be very helpful in controlling chronic pain. Traditionally it has been thought that pain control derives from antidromic activation of large-diameter primary afferents in the posterior columns, which inhibits activation of second-order neurons. ⋯ It is suggested that 'frequency-related conduction block' in the spinothalamic tract or in Lissauer's tract may play a role in pain relief. Because of uncertainty about the mechanism it is suggested that the term 'dorsal column stimulation' be replaced by 'spinal axis stimulation'.
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Applied neurophysiology · Jan 1981
Electrical stimulation of the spinal cord and peripheral nerves for pain control. A 10-year experience.
Patients who underwent implantation of dorsal column stimulators from 1970 to 1973 were reviewed 7-10 years following stimulation. The number who achieved satisfactory pain relief was not significant. The criteria for selecting these patients were reviewed utilizing those now used in 1980. 50% of the patients originally selected would now be rejected for psychological or drug-related reasons. ⋯ However, it appears that psychological factors were the most important reasons for failure. A smaller group of patients studied for 3-5 years following implantation of epidural spinal cord stimulators achieved a 70% pain control rate. Selection factors that explain these differences are discussed.
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A series of 101 patients with weakened neurological conditions (including multiple sclerosis and other demyelinating diseases) were augmented with dorsal column stimulation (DCS) over a 5 1/2-year period. 65 patients were implanted with an RF-linked system while 36 had a fully implantable programmable stimulator inserted. 20% failure occurred in the radio receiver series while none occurred in the latter, except for routine battery depletion. After 5 years, 23% of the patients using the RF system continued to use DCS, while after 4 years of using the fully implantable units, 81% of the patients continued to use DCS. Electrode displacement occurred in 27 patients, with breakage in a further 6 patients early in the series. Cathodal stimulation is more efficient that anodal stimulation when compared in 21 patients undergoing DCS.
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Applied neurophysiology · Jan 1981
Technological problems of spinal cord stimulation systems: a clinical perspective.
Technological problems of spinal cord stimulation, from the clinician's standpoint are the topics of this review of a round table discussion. Surgical aspects of spinal cord stimulation system implant procedures are reviewed. Safety and reliability of the methods and systems are discussed. Problems with durability and fixation of epidural electrodes are reported, and solutions are sought from the continued interaction of clinicians and biomedical engineers in the future development of methods and systems.
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This report is a continuation of our previous report on chronic spinal cord stimulation in disorders of the motor system. Improved statistics were observed following changing from the early conventional two-electrode system to a newly developed four-electrode system. ⋯ These are carried out on each patient and remain the most critical aspect of the technique. The details of the multiple lead system--the technique of implantation and protocols for carrying out electrode and frequency analysis--are presented.