The journal of pain : official journal of the American Pain Society
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Most patients who undergo surgical procedures experience acute postoperative pain, but evidence suggests that less than half report adequate postoperative pain relief. Many preoperative, intraoperative, and postoperative interventions and management strategies are available for reducing and managing postoperative pain. The American Pain Society, with input from the American Society of Anesthesiologists, commissioned an interdisciplinary expert panel to develop a clinical practice guideline to promote evidence-based, effective, and safer postoperative pain management in children and adults. The guideline was subsequently approved by the American Society for Regional Anesthesia. As part of the guideline development process, a systematic review was commissioned on various aspects related to various interventions and management strategies for postoperative pain. After a review of the evidence, the expert panel formulated recommendations that addressed various aspects of postoperative pain management, including preoperative education, perioperative pain management planning, use of different pharmacological and nonpharmacological modalities, organizational policies, and transition to outpatient care. The recommendations are based on the underlying premise that optimal management begins in the preoperative period with an assessment of the patient and development of a plan of care tailored to the individual and the surgical procedure involved. The panel found that evidence supports the use of multimodal regimens in many situations, although the exact components of effective multimodal care will vary depending on the patient, setting, and surgical procedure. Although these guidelines are based on a systematic review of the evidence on management of postoperative pain, the panel identified numerous research gaps. Of 32 recommendations, 4 were assessed as being supported by high-quality evidence, and 11 (in the areas of patient education and perioperative planning, patient assessment, organizational structures and policies, and transitioning to outpatient care) were made on the basis of low-quality evidence. ⋯ This guideline, on the basis of a systematic review of the evidence on postoperative pain management, provides recommendations developed by a multidisciplinary expert panel. Safe and effective postoperative pain management should be on the basis of a plan of care tailored to the individual and the surgical procedure involved, and multimodal regimens are recommended in many situations.
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Observational Study
The influence of chronic pain on post-operative pain and function after hip surgery: a prospective observational cohort study.
Pre-existing or chronic pain is an established risk factor for severe postoperative pain. In this prospective observational cohort study, we investigated whether a history of chronic pain, beyond the presence of hip-related pain, affected other postoperative factors including early mobilization, function, and psychological distress after hip surgery. Patients who underwent total hip replacement surgery were observed from the preoperative day until the seventh postoperative day. Before surgery, they were characterized by their pain history, pain intensity, function, and psychological characteristics. Postoperatively, pain intensity was evaluated on day 1, 3, 5, and 7 and the analgesic consumption was recorded for each of these days. Measures of function (functional questionnaire, ability to mobilize and to climb stairs, and range of hip motion) and psychological distress were re-evaluated on day 7. A history of chronic pain was associated with slower postoperative mobilization, poorer physical function, and greater psychological distress in addition to increased postoperative pain intensity. The comorbidity of a chronic pain disorder resulted in greater pain intensity after surgery, and also impeded postoperative rehabilitation. Identification of patients with a chronic pain disorder is necessary preoperatively so that appropriate pain management and rehabilitation can be planned to facilitate recovery. ⋯ Chronic pain, beyond the presence of hip-related pain, is associated with slower postoperative mobilization, poorer physical function, and greater psychological distress after total hip replacement surgery. Identification of patients with chronic pain and establishment of multiprofessional perioperative management might improve postoperative rehabilitation of patients with chronic pain.
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Comparative Study
Reorganized Trunk Muscle Activity During Multi-Directional Floor Perturbations After Experimental Low Back Pain: A Comparison Of Bilateral Versus Unilateral Pain.
Low back pain changes trunk muscle activity after external perturbations but the relationship between pain intensities and distributions and their effect on trunk muscle activity remains unclear. The effects of unilateral and bilateral experimental low back pain on trunk muscle activity were compared during unpredictable multidirectional surface perturbations in 19 healthy participants. Pain intensity and distribution were assessed using a visual analogue scale (VAS) and pain drawings. Root mean square (RMS) of the electromyographic (EMG) signals from 6 trunk muscles bilaterally after each perturbation was extracted and averaged across perturbations. The difference (ΔRMS-EMG) and absolute difference (absolute ΔRMS-EMG) RMS from baseline conditions were extracted for each muscle during pain conditions and averaged bilaterally for back and abdominal muscle groups. Bilateral compared with unilateral pain induced higher VAS scores (P < .005) and larger pain areas (P < .001). Significant correlation was present between VAS scores and muscle activity during unilateral (P < .001) and bilateral pain (P < .001). Compared with control injections ΔRMS-EMG increased in the back (P < .03) and abdominal (P < .05) muscles during bilateral and decreased in the back (P < .01) and abdominal (P < .01) muscles during unilateral pain. Bilateral pain caused greater absolute ΔRMS-EMG changes in the back (P < .01) and abdominal (P < .01) muscle groups than unilateral pain. ⋯ This study provided novel observations of differential trunk muscle activity in response to perturbations dependent on pain intensity and/or pain distribution. Because of complex and variable changes the relevance of clinical examination of muscle activity during postural tasks is challenged.
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Depression, pain catastrophizing, and anxiety commonly co-occur with chronic pain. However, the degree to which improvement in these psychological comorbidities predicts subsequent pain outcomes and, in particular, the relative effects of these 3 psychological factors with respect to each other is only partially known. Longitudinal analysis of 250 primary care patients with chronic musculoskeletal pain enrolled in the Stepped Care to Optimize Pain care Effectiveness (SCOPE) trial was examined, using data gathered at baseline, and at 3 and 12 months. Mixed effects model repeated measures analyses were used to determine if changes in depression, pain catastrophizing, and anxiety predicted a subsequent reduction in pain intensity or interference and pain-related disability. Defining a clinically significant change as twice the standard error of measurement for each predictor, we found that a 2-standard error of measurement improvement in depression, pain catastrophizing, and anxiety resulted in, respectively, an effect size decrease in pain intensity or interference of .45, .33, and .12; a 14%, 12%, and 6% reduction in the number of pain-specific disability days; and a 43%, 30%, and 28% decreased likelihood of high disability (defined as ≥10 pain-specific disability days in the past 4 weeks). In summary, improvements in 3 common psychological comorbidities predicted better pain outcomes. ⋯ Because depression, pain catastrophizing, and anxiety commonly accompany chronic pain and might adversely affect pain outcomes, treatment of these modifiable psychological factors is warranted to optimize the effectiveness of pain-specific therapies.
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Expectation and previous experience are both well established key mediators of placebo and nocebo effects. However, the investigation of their respective contribution to placebo and nocebo responses is rather difficult because most placebo and nocebo manipulations are contaminated by pre-existing treatment expectancies resulting from a learning history of previous medical interventions. To circumvent any resemblance to classical treatments, a purely psychological placebo-nocebo manipulation was established, namely, the "visual stripe pattern-induced modulation of pain." To this end, experience and expectation regarding the effects of different visual cues (stripe patterns) on pain were varied across 3 different groups, with either only placebo instruction (expectation), placebo conditioning (experience), or both (expectation + experience) applied. Only the combined manipulation (expectation + experience) revealed significant behavioral and physiological placebo-nocebo effects on pain. Two subsequent experiments, which, in addition to placebo and nocebo cues, included a neutral control condition further showed that especially nocebo responses were more easily induced by this psychological placebo and nocebo manipulation. The results emphasize the great effect of psychological processes on placebo and nocebo effects. Particularly, nocebo effects should be addressed more thoroughly and carefully considered in clinical practice to prevent the accidental induction of side effects. ⋯ Even purely psychological interventions that lack any resemblance to classical pain treatments might alter subjective and physiological pain correlates. A manipulation of treatment expectation and actual treatment experience were mandatory to elicit this effect. Nocebo effects were especially induced, which indicated the necessity for prevention of accidental side effects besides exploitation of placebo responses.