Pain
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In 28 Sprague-Dawley rats, unilateral division of the sciatic nerve at the level of the midfemur was performed. Animals were observed for behavioral changes for 1-21 days, and electrophysiological recordings were made from microfilaments dissected from the ipsilateral L5 dorsal rootlets and sciatic nerve from 1 to 14 days postoperatively. Spontaneous discharges of two types were recorded: (1) variable frequency (0-100 Hz) discharges which typically occurred in rhythmic bursts and could be driven by mechanical stimulation of the neuroma; and (2) lower frequency (0.25-14 Hz) irregular activity which persisted after either excision or local anesthesia of the neuroma. ⋯ This study demonstrates that peripheral axotomy of DRG neurons produces spontaneous activity distinct from ongoing neuroma activity in a proportion of fibers which are potentially nociceptive (A delta) as well as abnormal mechanosensitivity of the DRG. Furthermore, electrical stimulation of these fibers produces prolonged inhibition of the discharge. This finding may partially explain the prolonged relief of symptoms patients with chronic pain of peripheral origin may experience following peripheral tetanic electrical stimulation.
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This study examined relationships between chronic pain patients' ratings of pain severity, and other patient ratings about severity of associated impairment, and a series of behavioral measures of health care utilization and activity patterns. Prior to being evaluated, a sample of 150 chronic pain patients completed diary forms on which they recorded severity of pain on a 0-10 scale. Subjects were divided into high-medium-low on mean pain ratings, and were compared on the other measures obtained either from diary forms or at time of evaluation. ⋯ However, these measures showed few relationships to medication consumption, health care utilization, diary recorded activity level, or to patient reported frequency counts of engaging in a set of commonplace activities. The results were interpreted to suggest that, in chronic pain, there may be a questionable relationship between what people say about their pain and what they do. Accordingly, the evaluation of chronic pain should include analyses of patient behavior.
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Children and adolescents with recurrent migraine headaches or musculo-skeletal pain were asked to draw a picture of their pain and another picture of themselves in pain. The drawings were categorized according to content and color. ⋯ Children with recurrent migraine more often drew themselves doing something to relieve their pain, than did children with musculo-skeletal pain. Implications for the use of pain drawings in the treatment of chronic and recurrent pain are discussed.
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The incidence and clinical picture of non-painful and painful phantom limb sensations as well as stump pain was studied in 58 patients 8 days and 6 months after limb amputation. The incidence of non-painful phantom limb, phantom pain and stump pain 8 days after surgery was 84, 72 and 57%, respectively. Six months after amputation the corresponding figures were 90, 67 and 22%, respectively. ⋯ During the follow-up period the localization of phantom pains shifted from a proximal and distal distribution to a more distal localization. While knifelike, sticking phantom pains were most common immediately after surgery, squeezing or burning types of phantom pain were usually reported later in the course. Possible mechanisms for the present findings either in periphery, spinal cord or in the brain are discussed.
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Clinical Trial Controlled Clinical Trial
Postoperative pain control: contribution of psychological factors and transcutaneous electrical stimulation.
The influence of transcutaneous electrical stimulation (TES) and psychological factors in determining the intensity of acute postoperative pain was examined in a prospective, double-blind controlled trial completed by 30 patients having elective surgery. Psychometric tests were administered prior to surgery. Postoperative pain was assessed by cumulative morphine requirement (M48) administered intramuscularly, and the mean score of a visual analogue scale of pain (VAS), in the first 48 h following surgery. ⋯ When the contribution of neuroticism to the variance of M48 was adjusted using multiple regression analysis, the effect of TES became significant at the 0.05 level. Covariance analysis showed that TES contributed some 19% to the explained variance of M48 while neuroticism contributed about 80%, and there was no interaction between these two factors. These findings allow a degree of prediction of the individual patient's postoperative pain and narcotic requirement, and point to a strong correlation between postoperative pain perception and personality.