Pain
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Cryoanalgesia, the technique of freezing peripheral nerves, is used clinically for the treatment of postoperative and chronic pain. Paradoxically, this same technique produces characteristics in a rat model suggestive of neuropathic pain. We have developed a peripheral neuropathy model by freezing the proximal sciatic nerve (sciatic cryoneurolysis, SCN) using a cryoprobe cooled to -60 degrees C in a 30/5/30 sec freeze-thaw-freeze sequence. ⋯ The transient time course of certain behaviors including hypoesthesia and possible return of limb sensation, autotomy, touch-evoked allodynia, foot edema and the presence of spontaneous nociceptive behaviors demonstrate a multiple phase nociceptive process. The temporary nature of these nociceptive behaviors is in sharp contrast to the prolonged bilateral mechanical allodynia evident when these behaviors subside. The surgical anesthetics used during the SCN procedure are shown to variably alter or suppress autotomy following SCN.(ABSTRACT TRUNCATED AT 250 WORDS)
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Previous research has demonstrated a relationship between the use of pain coping strategies and the level of pain and psychological distress experienced by patients suffering from a variety of chronic pain syndromes. The present study assessed coping strategy use in patients suffering from phantom limb pain by means of the Coping Strategies Questionnaire (CSQ). Sixty phantom limb pain patients completed the CSQ and measures of pain and psychological distress. ⋯ Twenty percent of the variance in pain scores and 19% of the variance in psychological distress were significantly explained by coping strategies included in the 3 factors on the CSQ. Patient history variables significantly explained a further 14% of the variance in pain scores and 14% of the variance in psychological distress. Examination of regression analyses of the subscales of the CSQ revealed that catastrophising explained the largest proportion of the variance in pain report and psychological distress.
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An experimental arthritis induced by injection of kaolin and carrageenan into the knee joint resulted in a temporal relationship between glutamate dorsal horn content and paw withdrawal latency (PWL) which was positively correlated. Limping, guarding, increased response to heat stimuli (hyperalgesia) and altered staining patterns for glutamate (GLU), substance P (SP), and calcitonin gene-related peptide (CGRP) were monitored in the awake behaving arthritic rat over a 1 week time course. A decrease in PWL occurred on the side ipsilateral to the inflamed knee as early as 4 h after the induction of arthritis indicating the animals are hyperalgesic. ⋯ Rather, there was an increase in CGRP content in the middle portion of the superficial dorsal horn which is the termination site of knee joint afferents. These data indicate that the development of heat hyperalgesia is dependent on GLU and possibly SP. Since inflammation of the knee joint does not involve the foot pad, the heat hyperalgesia observed during the first 24 h following induction of arthritis represents a central neuronal sensitization.
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Review Case Reports
Reflex sympathetic dystrophy treated by electroconvulsive therapy: intractable pain, depression, and bilateral electrode ECT.
An adult female patient without previous history of pain or psychiatric disorder developed reflex sympathetic dystrophy (RSD) in her left hand and arm after 2 separate injuries, and subsequent arthroscopy and arthroscopic surgery. Traditional management with systemic medications, nerve blocks, and behavioral pain management were unsuccessful. With subsequent development of depression and suicide attempt, electroconvulsive therapy (ECT) was administered using bilateral lead placement. ⋯ A review of the literature from the 1940s revealed numerous cases of chronic, intractable pain treated successfully by ECT, although none of the case series were controlled studies. More recent literature questions if 'modified' ECT, using unilateral lead placement, is less effective than bilateral lead placement, in treating pain syndromes. Resolution of the vascular changes of RSD after ECT raises questions of possible cerebral contributions to the pathophysiology of RSD.
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Over a 3-year period, neurolytic abdominal visceral sympathectomy was performed bilaterally with 15 ml of alcohol solution (14 ml of alcohol and 1 ml of contrast material) through each needle under CT guidance to relieve upper abdominal or back pain in 27 cancer patients. Using the CT monitor, our intention was to achieve splanchnic nerve neurolysis rather than celiac plexus neurolysis. After determining the trajectory for needle placement on the CT image at the L1 level, the needles were inserted bilaterally with a simple guide apparatus. ⋯ It was speculated that the alcohol spread through the aortic hiatus or gaps of the diaphragmatic crura. No neurologic complications were encountered. It is concluded that CT guided alcohol splanchnic nerve neurolysis is an effective treatment for upper abdominal cancer pain, and that 15 ml of alcohol solution through each needle is enough for splanchnic nerve neurolysis.