Surg Neurol
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Twenty-seven patients with chronic pain had dorsal column stimulators implanted for pain control over a period of three years. Technical factors of electrode placement and type of unit were not found to correlate with the degree of pain relief. The preoperative psychological attitude of the patient correlated highly with the degree of pain relief and was the single most important factor in patient selection and evaluation. Theoretical concepts of pain psychophysiology in relation to the gate theory and areas for more extensive investigation of pain are discussed.
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A number of patients with intractable pain were subjected to electrical stimulation of the nucleus ventralis posterolateralis. Positive results obtained support the theory according to which pain is caused by lack of proprioceptive stimuli reaching the thalamus. The implantation technique is discussed and improvements of electrodes and of the device are proposed. Optimal stimulation parameters are defined.