The Clinical journal of pain
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Observational Study
Influences of COMT rs4680 and OPRM1 rs1799971 Polymorphisms on Chronic Postsurgical Pain, Acute Pain and Analgesic Consumption After Elective Caesarean Delivery.
The main objectives of this study were to assess the effects of cathechol-O-methyl-transferase (COMT) rs4680 and μ-opioid receptor rs1799971 polymorphisms alone or genotype combinations on chronic postsurgical pain (CPSP), acute pain, and analgesic consumption after elective cesarean delivery in a Chinese cohort. ⋯ Our results indicate that cathechol-O-methyl-transferase rs4860 and μ-opioid receptor rs1799971 may not contribute to CPSP development after cesarean delivery. The genotype of rs1799971 affects postcesarean analgesic requirement, while the rs4680 do not. Additional larger studies are needed to confirm these findings.
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Numbness associated with neuropathic pain suggests the loss of function in myelinated, large diameter sensory neurons. The purpose of this study was to examine the relationships between pain severity and subjective (ie, severity of numbness) and objective (ie, loss of light touch sensations, vibration thresholds) measures of loss of large fiber function in adult survivors with chemotherapy-induced peripheral neuropathy (CIPN, n=426) and breast cancer patients with persistent postsurgical pain (n=80). ⋯ Our findings, in 2 independent samples of oncology patients, suggest that loss of function of myelinated, large diameter fibers contributes to the severity of neuropathic pain.
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Observational Study
Evaluation of the Neuropathic Component of Chronic Low Back Pain.
Assessment of neuropathic pain in chronic low back syndromes is important. However, there is currently no gold standard for its diagnosis. The aim of this observational cross-sectional study was to assess the neuropathic component of pain in various chronic low back pain syndromes using a range of diagnostic tests. ⋯ Neuropathic pain is quite frequent in CRS, and QST reveals sensory loss as a frequent abnormality in patients with CRS. Using a cut-off value of 19, PDQ identified a neuropathic component in a relatively low proportion of patients with CRS. CRS may be associated with a reduction in IENFD.
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Randomized Controlled Trial
Staircase-evoked Pain may be More Sensitive than Traditional Pain Assessments in Discriminating Analgesic Effects: A Randomized, Placebo-controlled Trial of Naproxen in Patients with Osteoarthritis of the Knee.
Analgesic trials often fail to show a significant effect even when medications with known efficacy are tested. This could be attributed to insufficient assay sensitivity of analgesic trials, which may be due, in part, to the insensitivity of pain-related outcome measures. The aim of this methodological study was to assess the responsiveness of evoked pain generated by the staircase procedure compared with other commonly used pain outcomes in knee osteoarthritis. ⋯ Study results support our hypothesis that evoked pain using the StEPP may demonstrate greater responsiveness to treatment effects compared with traditional pain-related outcome measures. Accordingly, these results may facilitate development and validation of other chronic pain-related evoked pain models, which could contribute to future research and development of new analgesics.
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The effects of eccentric exercises on clinical outcomes and central pain mechanisms are unclear in neck/shoulder pain (NSP). The aims were to: (1) evaluate the clinical impact of unilateral eccentric training in female computer users with chronic NSP; (2) compare pressure pain sensitivity, temporal summation of pain (TSP); and conditioned pain modulation (CPM) in female office workers with and without NSP; and (3) assess sensitization and central pain responses after training. ⋯ Eccentric training improved pain and disability, reduced sensitization, and enhanced CPM efficiency in female computer users with NSP.