Pain
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Small-scale studies have suggested a large inter-individual variation in early postoperative pain after laparoscopic cholecystectomy, emphasizing the need for improved analgesic treatment and valid predictors. We investigated prospectively the association between a preoperative nociceptive stimulus by ice water (cold pressor test), neuroticism, dyspepsia, patient history of biliary symptoms, intraoperative factors, and demographic information in 150 consecutive patients undergoing uncomplicated laparoscopic cholecystectomy for their influence on early postoperative pain. During the first postoperative week patients registered overall pain, incisional, visceral, and shoulder pain on a visual analogue scale and verbal rating scale, and daily analgesic requirements were noted. ⋯ Incisional pain dominated in incidence and intensity compared with visceral pain, which in turn dominated over shoulder pain. In a multivariate analysis model, preoperative neuroticism, sensitivity to cold pressor-induced pain, and age were identified as independent risk factors for early postoperative pain. Our results suggest that future analgesic studies after laparoscopic cholecystectomy should focus on reduction of incisional pain.
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This study investigated sex and age cohort differences in the subjective report of orofacial pain symptoms in a stratified sample of community dwelling adults. The subjects were 724 participants in the Florida Dental Care Study, a longitudinal study of oral health among dentate adults, age 45 and older at baseline. Pain prevalence and subjective ratings were assessed for a range of orofacial pain sites using a standardized telephone interview. ⋯ Few overall age effects were found, with the exception of higher prevalence of temperature sensitivity and pain when chewing in the 45--64-year-old group, compared to respondents in the 65+ age cohort. However, the most interesting finding was that when sex by age cohort comparisons were made, with the exception of painful oral sores, all significant differences in pain ratings were found within the 45--64-year-old cohort and not the 65+ group. This finding clarified inconsistencies found in earlier studies in the orofacial pain literature where sex differences in pain ratings were found in several adult samples of a wide range of ages but not in a sample of older adults.
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We have examined the effects of a novel GABA(B) agonist, CGP35024, in models of chronic neuropathic (partial sciatic ligation) and inflammatory (Freund's complete adjuvant) pain in the rat, and its inhibitory action on spinal transmission in vitro. The effects of CGP35024 were compared with L-baclofen and gabapentin. CGP35024 and L-baclofen reversed neuropathic mechanical hyperalgesia following single subcutaneous or intrathecal administration, but did not affect inflammatory mechanical hyperalgesia. ⋯ In the isolated hemisected spinal cord from the rat, CGP35024, L-baclofen and gabapentin all inhibited capsaicin-evoked ventral root potentials (VRPs). CGP35024 and L-baclofen, but not gabapentin, also inhibited the polysynaptic and monosynaptic phases of electrically-evoked VRPs, as well as the 'wind-up' response to repetitive stimulation. These data indicate that CGP35024 and L-baclofen modulate nociceptive transmission in the spinal cord to inhibit neuropathic hyperalgesia, and that CGP35024 has a therapeutic window for antihyperalgesia over spasmolysis.
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Clinical Trial Controlled Clinical Trial
Hyperalgesic responses in methadone maintenance patients.
Opioid substitution treatment for dependence may alter sensitivity to pain. Previous studies on pain sensitivity in methadone maintenance patients have yielded contradictory results. This study compared nociceptive responses between 16 patients on stable, once daily, doses of methadone and 16 matched control subjects. ⋯ Pain tolerance to pain detection ratios for methadone patients were significantly lower than controls for the cold pressor test at 0 and 3 h, and for electrical stimulation at 0 h only. In summary, the relative pain sensitivity of methadone maintenance patients is determined by the nature of the nociceptive stimulus (e.g. cold pressor test versus electrical stimulation), the plasma methadone concentration (trough versus peak plasma concentration), and whether thresholds are determined for detection of pain or pain tolerance. Although responding to changes in plasma methadone concentration, maintenance patients are markedly hyperalgesic to pain induced by the cold pressor test.
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Cognitive-behavioral models of chronic pain hypothesize that how a person copes with pain influences how well he or she adjusts to the pain. Several measures have been developed to assess pain coping, but no studies have yet examined whether these measures are complementary or redundant. In the current study, two pain coping measures (the Chronic Pain Coping Inventory, CPCI, and the Coping Strategies Questionnaire, CSQ) were completed by a large number (N=564) of primarily male veterans referred to a chronic pain program. ⋯ The findings of this study are consistent with cognitive-behavioral models of pain. Future research will need to determine whether changes in coping responses (catastrophizing and guarding, in particular) merely reflect, or actually influence, adjustment to chronic pain. In the meantime, clinicians would be wise to give these coping responses particular attention in chronic pain programs.