Pain
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A 41-year-old female developed spontaneous burning pain (causalgia) and stimulus-induced dysesthesia (allodynia) of the dorso-lateral part of her right foot following trauma. An L3 and L4 sympathectomy eliminated the spontaneous burning pain for only 1 year, but did not affect the stimulus-induced dysesthesia. We evaluated her two years post-sympathectomy with grouped sequential anesthetic blocks and sensory testing. ⋯ When sural block was added to the peroneal block the stimulus-induced dysesthesia was eliminated, and sensation in the sural distribution was lost. We conclude that the sural distribution received overalapping innervation for touch and pin-prick perception, but that heat perception, burning pain and the stimulus-induced dysesthesia were sural nerve dependent. Further, we were able to dissociate causalgia pain from allodynia in this patient.
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The present study examined the reliability and validity of a daily activity diary for chronic pain patients. The diary assesses various postures and activities including time spent lying, sitting, or standing/walking, the use of pain relief devices, time spent in pain relief activities, and the use of analgesic medications. The methodology compared patient self-report on the daily activity diary to spouse observations of the same activities. ⋯ Finally, the correlation between patient report of lying down time and downtime as measured by the electromechanical monitor was also positive and highly significant. These results indicate that the daily activity diary is a reliable and valid instrument for the assessment of daily activity patterns of chronic pain patients in their natural environment. These results are discussed in relation to other research and the use of daily diaries for assessment and treatment outcome research with this population.
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Clinical Trial Controlled Clinical Trial
Concomitant increase in nociceptive flexion reflex threshold and plasma opioids following transcutaneous nerve stimulation.
In order to evaluate the role of endogenous opioids in sustaining analgesia induced by transcutaneous nerve stimulation (TNS), we measured plasma beta-lipotropin (BLPH), beta-endorphin (BEP), ACTH and cortisol changes concomitantly with nociceptive flexion reflex (RIII) threshold after TNS (80 microseconds rectangular waves at 85 Hz) in a group of healthy volunteers (A). The same protocol was carried out in another group of volunteers using placebo stimulation (0.5 Hz) (B). RIII threshold significantly increased 0.5 h after TNS in group A and no changes were recorded in group B. ⋯ A positive linear correlation was found between the maximum percentage increase of RIII threshold after high frequency TNS and the maximum percentage increase of BLPH plasma levels occurring 20 min beforehand (r = 0.856, P less than 0.001). A less positive correlation was found between RIII and BEP levels (r = 0.574, P less than 0.05). These data indicate that the so-called post-stimulation analgesia could be supported by the enhancement of the endogenous opioid system.
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Comparative Study
Relief of cancer pain in man: alcohol-induced neuroadenolysis vs. electrical stimulation of the pituitary gland.
To explore new methods for the control of intractable pain caused by advanced cancer, the analgesic effect of electrical stimulation of the pituitary gland was investigated in 25 patients. The results were compared with a control study and with the effects of alcohol-induced pituitary neuroadenolysis (NALP) in the same patients. The pain score (0: no pain at all, 4: extreme pain) in the control study was 3.88 +/- 0.33. ⋯ Autopsy examinations of 3 patients who expired from their malignancies revealed that the pain relief was unrelated to the degree of necrosis induced in the pituitary by alcohol. Naloxone administration did not inhibit the analgesic effect of either NALP or electrical stimulation. The advantages and disadvantages of electrical stimulation, the pain relief mechanism activated by this method, and potential clinical applications are also discussed.