The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Changes of hypertonic saline-induced masseter muscle pain characteristics, by an infusion of the serotonin receptor type 3 antagonist granisetron.
This study aimed to investigate whether granisetron reduces masseter muscle pain and allodynia induced by hypertonic saline. Fifteen healthy women and 15 age-matched healthy men participated in this randomized, placebo-controlled, double-blinded study. They first received bilateral injections of hypertonic saline into the masseter muscles (internal control). The evoked pain intensity and the pressure-pain threshold (PPT) were recorded during 30 minutes. Granisetron was then injected on one side and placebo (normal saline) on the contralateral side. Two minutes thereafter, the hypertonic saline injections were repeated. Pain and PPT were again recorded. The first injection of hypertonic saline induced pain of similar intensity, duration, and pain area on both sides, but with larger pain area in the women (P = .017). The PPT did not change significantly. The second injection of hypertonic saline induced considerably less pain (62.5%), of shorter duration (44.1%), and of smaller area (77.4%) on the side pretreated with granisetron (P = .005). The PPT was increased on the granisetron side in the men (P = .002). The results of this study show that local injection of a single dose of granisetron attenuates masseter muscle pain induced by hypertonic saline. ⋯ This article presents the changes of hypertonic saline-induced masseter muscle pain characteristics by infusion of granisetron. It appears that the pain-inducing effect in this experimental pain model is partly due to activation of 5-HT3-receptors. Hence, the results indicate that granisetron might offer a new treatment approach for localized myofascial pain.
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Multicenter Study Comparative Study
Common chronic pain conditions in developed and developing countries: gender and age differences and comorbidity with depression-anxiety disorders.
Although there is a growing body of research concerning the prevalence and correlates of chronic pain conditions and their association with mental disorders, cross-national research on age and gender differences is limited. The present study reports the prevalence by age and gender of common chronic pain conditions (headache, back or neck pain, arthritis or joint pain, and other chronic pain) in 10 developed and 7 developing countries and their association with the spectrum of both depressive and anxiety disorders. It draws on data from 18 general adult population surveys using a common survey questionnaire (N = 42,249). Results show that age-standardized prevalence of chronic pain conditions in the previous 12 months was 37.3% in developed countries and 41.1% in developing countries, with back pain and headache being somewhat more common in developing than developed countries. After controlling for comorbid chronic physical diseases, several findings were consistent across developing and developed countries. There was a higher prevalence of chronic pain conditions among females and older persons; and chronic pain was similarly associated with depression-anxiety spectrum disorders in developed and developing countries. However, the large majority of persons reporting chronic pain did not meet criteria for depression or anxiety disorder. We conclude that common pain conditions affect a large percentage of persons in both developed and developing countries. ⋯ Chronic pain conditions are common in both developed and developing countries. Overall, the prevalence of pain is greater among females and among older persons. Although most persons reporting pain do not meet criteria for a depressive or anxiety disorder, depression/anxiety spectrum disorders are associated with pain in both developed and developing countries.
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Chronic pain is a common complication after thoracic surgery. The cause of chronic post-thoracotomy pain is often suggested to be intercostal nerve damage. Thus chronic pain after thoracic surgery should have an important neuropathic component. The present study investigated the prevalence of the neuropathic component in chronic pain after thoracic surgery. Furthermore, we looked for predictive factors for prevalence and intensity of chronic pain. We contacted 243 patients who underwent a video-assisted thoracoscopy (VATS) or thoracotomy in the period between January 2004 and September 2006 by mail. Patients retrospectively received a questionnaire with the Dutch version of the PainDETECT Questionnaire, a validated screening tool for neuropathic pain. Results were analyzed from 204 patients (144 thoracotomies, 60 VATS). The prevalence of chronic pain was 40% after thoracotomy and 47% after VATS. Definite chronic neuropathic pain was present in 23% of the patients with chronic pain, with an additional 30% having probable neuropathic pain. Greater probability of neuropathic pain (ie, a higher total score of the PainDETECT) correlated with more intense chronic pain. Predictive factors for chronic pain were younger age (P = .01), radiotherapy (P = .043), pleurectomy (P = .04) and more extensive surgery (P < .001). ⋯ Up to half the chronic pain after thoracic surgery is not associated with a neuropathic component, which has not been reported to date. More extensive surgery and pleurectomy are predictive factors for chronic pain after thoracic surgery, suggesting a visceral component apart from nerve injury.
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Preoperative identification of patients at risk for high-intensity postoperative pain may be used to predict patients at risk for development of a persistent pain state and allocate patients to more intensive specific pain therapy. Preoperative pain threshold to electrocutaneus stimulation has recently been shown to correlate to acute postoperative pain after cesarean section, but the findings have not been confirmed in larger studies or other procedures. Preoperative electrical pain detection threshold and pain tolerance were assessed in patients undergoing a primary unilateral groin hernia repair. The correlation between the pain data for electrical stimulation was compared with the postoperative pain during the first week in 165 patients, whereof 3 were excluded. Preoperative electrical pain detection threshold and electrical pain tolerance threshold did not correlate to postoperative pain (rho = -0.13, P = .09, and rho = -1.2, P = .4, respectively. ⋯ Although preoperative electrical nociceptive stimulation may predict patients at risk of high-intensity acute pain after other surgical procedures, this was not the case in groin hernia repair patients receiving concomitant treatment with acetaminophen and ibuprofen.
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Although there are several reports on pain behavioral tests in rat models of knee osteoarthritis (OA), most of them focus on the paw. The aim of this study was to investigate pain-related behaviors on the affected knee joint, the primary source of nociception, in animals with mono-iodoacetate-induced OA, using the knee-bend (which provides information on movement pain) and pin-prick tests, and to evaluate nociception elicited by walking using the CatWalk test. The von Frey and Randall-Selitto tests applied to the paw allowed us to compare our study results with previous studies. A further aim was to compare the behavioral nociceptive responses of the most used doses of mono-iodoacetate, 2 and 3 mg. Knee-bend score of OA animals was higher than those of control animals throughout the study (P < .05). At every time point, the ipsilateral hind-paw load of OA rats, as measured by the CatWalk test, was lower than that of control rats (P < .05), and paw withdraw threshold to von Frey filaments was also decreased (P < .01). No changes were observed in pin-prick and Randall-Selitto tests. Results obtained with the 2 doses of mono-iodoacetate were similar. The knee-bend and CatWalk tests are effective for evaluating movement-related nociception, a hallmark of clinical OA, which was present throughout the experimental period. ⋯ Behavioral characterization of models of OA pain is important and useful for use in future studies to test pharmacological treatments. Furthermore, it is important to find methods that correlate better with the human symptoms of OA.