Pain
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Randomized Controlled Trial
Differential sensitivity of three experimental pain models in detecting the analgesic effects of transdermal fentanyl and buprenorphine.
This is the first randomized controlled trial that tests the analgesic efficacy of transdermally delivered opioids in healthy volunteers and that assesses the sensitivity of different experimental pain tests to detect analgesia in this setting. Transdermal application of the full agonist fentanyl (TDF: 12.5 or 25 microg/h) and the partial agonist buprenorphine (TDB: 35 microg/h) was compared in three experimental models of acute pain (heat pain, painful electrical stimulation, cold pressor) in a double-blind, randomized, placebo-controlled, 4-arm crossover study with 20 healthy subjects (15 men, 5 women). Patches were administered for 72 h and pain levels measured at baseline and 24 and 72 h, with an 11-day wash-out. ⋯ We conclude that the cold pressor test was most sensitive to analgesic effects in healthy subjects and that a transdermal dose of 12.5 microg/h fentanyl achieved significant pain reduction compared with placebo. Subjects experienced opioid-typical AEs including dizziness, nausea and vomiting. No serious AEs occurred.
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Randomized Controlled Trial
Efficacy and safety of acupuncture for chronic uncomplicated neck pain: a randomised controlled study.
Chronic neck pain is highly prevalent. To determine the efficacy and safety of acupuncture, in comparison with transcutaneous nerve stimulation-placebo (TENS-placebo) in the treatment of chronic uncomplicated neck pain, a single blind prospective study was designed, to be carried out at a Primary Healthcare Centre, with random assignment to two parallel groups and with evaluation and analysis by independent evaluators. A random assignment was made from 123 patients of the 149 initially recruited. ⋯ By ITT analysis, the change in the pain-VAS variable was greater among the experimental group (28.1 (95% CI 21.4-34.7)). The improvements in quality of life (physical aspect), active neck mobility and reduced rescue medication were clinically and statistically significant. In the treatment of the intensity of chronic neck pain, acupuncture is more effective than the placebo treatment and presents a safety profile making it suitable for routine use in clinical practice.
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Randomized Controlled Trial
Categories of placebo response in the absence of site-specific expectation of analgesia.
Experimental placebo analgesia is induced by building an expectation of reduced pain in a specific body part, usually using an inert cream in the guise of a local anaesthetic in conjunction with conditioning. We investigated non-site-specific placebo analgesia by conditioning subjects to expect the anaesthetic cream on one arm, without specifying if they will definitely receive the cream, or to which arm it might be applied. Painful heat pulses (150 ms) from a CO2 laser were delivered randomly to both arms. ⋯ In the treatment group, we observed a range of placebo responses: unilateral responders (33.3%), subjects with a placebo response in the conditioned arm only; bilateral responders (33.3%), subjects reporting reduction in the intensity ratings in both arms, and non-responders, whose intensity ratings were not influenced by conditioning. We discuss these responses in terms of different levels of expected analgesia, facilitated by the absence of a site-specific focus for the treatment. We suggest this allowed the individuals suggestibility to influence their assessment of the pain experience by combining different levels of expectation with the information from the actual pain stimulus.
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A significant number of patients who have had surgery for lumbosacral radicular syndrome still have a reduced work capacity several months later. In a prospective cohort study of 182 people who underwent lumbar disc surgery, we determined the predictive value of preoperatively measured cognitive-behavioral and work-related factors on work capacity 6 months after surgery. ⋯ Specifically, fear of movement/(re)injury, more passive pain coping, and higher physical work-load predicted reduced work capacity in multiple logistic regression analyses, taking into account the role of a wide range of control variables including demographic variables, preoperative disability and pain intensity, neurological deficits, intake of analgesics, duration of complaints, and pain intensity 3 days postoperatively. The study supports the need to develop and evaluate preoperative risk screening measures that include both cognitive-behavioral and work-related factors and to evaluate the effectiveness of cognitive-behavioral and work-related interventions in patients at risk of reduced work capacity after surgery for LRS.
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Low back pain is considered to fluctuate over time, and related prognostic factors may behave similarly, therefore classification of prognosis may be affected by timing of assessment. We aimed to investigate the implications of timing of assessment of prognosis in low back pain. In a prospective cohort of primary care low back pain consulters aged 30-59 years, 359 returned questionnaires at baseline, one-month and one-year. ⋯ Presence of the indicators at both time points was associated with even higher risk; people with persistent high pain intensity had 15 times the risk of a poor outcome (relative risk 15.1; 95% confidence interval 6.7-33.8) compared with people not reporting high pain at either point. Combining information on prognostic indicators from two time points provides better classification of low back pain patients' eventual outcome than a single measurement alone. This increased accuracy in predicting prognosis is relevant to both clinical and research practice.