Pain practice : the official journal of World Institute of Pain
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Pain-related fear avoidance (FA), a common problem for patients with painful medical conditions, involves pain-related catastrophizing cognitions, hypervigilance, and avoidance behaviors, which can ultimately lead to decreased functioning, depression, and disability. Several patient-reported instruments have been developed to measure FA, but they have been criticized for limited construct validity, inadequate item specificity, lack of cutoff scores, and missing important FA components. The Fear-Avoidance Components Scale (FACS) is a new patient-reported measure designed to comprehensively evaluate FA in patients with painful medical conditions. ⋯ FACS scores differentiated between 2 separate chronic pain patient samples and a nonpatient comparison group. When clinically relevant severity levels were created, FACS severity scores were highly associated with FA-related patient-reported psychosocial and objective lifting performance variables. These results suggest that the FACS is a psychometrically strong and reliable measure that can help healthcare providers assess FA-related barriers to function and recovery.
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Case Reports
Burst Spinal Cord Stimulation in a Patient with Complex Regional Pain Syndrome: A 2-year Follow-Up.
Spinal cord stimulation (SCS) is an effective therapy to treat most patients with complex regional pain syndrome (CRPS); however, the effect is not always maintained over time. We present a case report of a patient successfully treated with burst SCS after a diminishing effect of conventional tonic stimulation. Burst stimulation is a novel method of SCS consisting of delivering 5 spikes at 500 Hz, 40 times/s (pulse width 1 mseconds). The current output is set to a subthreshold level for paresthesia in the supine position. ⋯ In this patient with CRPS, burst SCS was successful in reducing pain scores that could no longer be achieved with conventional tonic stimulation. It appears that pain reduction with burst SCS can be sustained for a relatively long period of time.
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Low back pain is very common, but the pathophysiology is poorly understood. We present a new hypothesis regarding the pathophysiology of common low back pain supported by our flexible endoscopic observations of the epidural cavity (epiduroscopy), anatomic dissection of embalmed and fresh cadavers, and careful review of preexisting information available on the anatomy of the epidural space and neuroforamen. A new approach to the treatment of common low back pain based on the hypothesis was developed and is presented in the case reports of five patients. ⋯ Percutaneous Ablation and Curettage and Inferior Foraminotomy (PACIF(sm)) aims to destroy the peridural membrane, denervate sensitive structures, and remove inflammatory tissues from the suprapedicular canal. The proposed mechanism of action and safety of PACIF(sm) is discussed in the context of epidural and neuroforaminal anatomy. As shown by the five case reports, PACIF(sm) appears to be highly effective and safe, warranting further evaluation.
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Randomized Controlled Trial
Efficacy and Tolerability of Subcutaneous Methylnaltrexone in Patients with Advanced Illness and Opioid-Induced Constipation: A Responder Analysis of 2 Randomized, Placebo-Controlled Trials.
Subcutaneous methylnaltrexone is efficacious and well tolerated in inducing bowel movements in patients with advanced illness and opioid-induced constipation (OIC); factors determining optimal responsiveness to OIC treatment, however, have not been elucidated. This post hoc responder analysis examined the influence of demographic and baseline characteristics on methylnaltrexone efficacy and tolerability in this population. ⋯ Subcutaneous methylnaltrexone provides a rapid, robust, and consistent RFBM response in patients with advanced illness and OIC. Methylnaltrexone 0.30 mg/kg may elicit particularly favorable responses in select patient populations.
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On an individual level, there is a difference in the analgesic response to a given opioid. Various factors such as gender, age, and genetic variation can affect the analgesic response. ⋯ We present recent experimentally induced pain, postoperative pain, and cancer pain and chronic non-malignant pain conditions studies in humans, focusing on the association between genetic variation and analgesic response assessed as opioid consumption or changes in pain scores. Studies have shown promising results regarding pharmacogenetics as a diagnostic tool for predicting the individual response to a given opioid in the experimental settings; however, in the clinic, it is a more complicated task to accomplish.