Pain
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Our experience in treating 10 patients with intractable pain with paraplegia employing percutaneous epidural or dorsal column stimulation is presented. Initial and long-term results in this group are contrasted with those of 9 patients with intractable post-amputation or post-traumatic neuroma pain. The successful results of neurostimulation treatment of peripheral nerve pain contasts with the disappointing results in the treatment of paraplegic pain.
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A survey of the literature is presented in two areas of biofeedback treatment for headache--muscle contraction and migraine--and a variety of miscellaneous pain syndromes. The studies done to date are characterized largely by lack of proper no-treatment or placebo control groups, by confounding biofeedback with a variety of other strategies, or by sample sizes too small to afford any reasonable conclusions about efficacy. There is some evidence that biofeedback works better for muscle contraction headache than false feedback, but it also appears that biofeedback is no more effective than relaxation training. ⋯ The potential influence of extraneous factors linked to the therapeutic situation is pervasive in these studies, but examination of their specific roles in symptom reduction is largely missing. Some variables are listed which need to be examined and which may contribute to the alleviation of pain with much less expenditure of clinical resources than that demanded by biofeedback. Perhaps the main contribution of biofeedback has been to highlight such extraneous variables in the pain treatment setting.
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Experimental C-fiber pain caused by radiant heat was applied to the skin area supplied by the left sural nerve of 20 subjects. Percutaneous electrical stimulation (PNS) was performed on the left sural nerve, the left superficial peroneal nerve and the right superficial radial nerve. Stimulation frequencies were: 3, 50, 100, 300, 500 and 1000 Hz. ⋯ Without considering the influence of the different frequencies, the best analgesic effects were reached if noxious heating and PNS were both performed on the left sural nerve; the anatomical conditions prevented us from distinguishing between the effects of possible peripheral blockade or spinal modification of pain. PNS of the superficial peroneal nerve seems to indicate spinal, possibly polysegmental, interactions between C-fiber pain and electrical stimulation of thick myelinated fibers. However, long loop effects may also play a part in local analgesia as demonstrated by PNS of the right radial nerve.
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Transcutaneous electrical nerve stimulation and the reaction to experimental pain in human subjects.
The effect of peripheral transcutaneous electrical nerve stimulation (TENS) on the reaction to experimental pain in human volunteers has been assessed. Placebo stimulation and electrical stimulation at moderate intensities failed to modify the response to the pain produced by conducted thermal stimuli. ⋯ The subjective pain assessment and the maximum pain tolerance produced by ischaemic pain after a submaximal effort tourniquet test were significantly modified by peripheral electrical stimulation at non-noxious intensities. The response to experimental pain can therefore be altered in man by peripheral electrical stimulation in a manner partly dependent on the sensory modality used for producing the experimental pain and on the intensity of the electrical stimulation.
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An evaluation of acupuncture for pain relief was made in 10 patients with sickle cell anaemia during 16 pain crises. A model was developed in which the patient served as his own control and in which both patient and examiner were unaware of whether an acupuncture point or a sham site was treated. The results show (1) that pain relief was obtained in 15 of the 16 painful episodes regardless of whether an acupuncture point or a sham site was treated, demonstrating considerable overlap between the effects of needling acupuncture points and sham sites; (2) that needling at acupuncture points for pain relief is not significantly superior to treatment at sham sites; (3) that needling, per se, whether at acupuncture points of at sham sites can be useful for alleviating pain in sickle cell crises. The model could be useful for evaluation of pain relief by needling in other diseases.