The journal of pain : official journal of the American Pain Society
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Intervertebral disc degeneration (DD) is a cause of low back pain (LBP) in some individuals. However, although >30% of adults have DD, LBP only develops in a subset of individuals. To gain insight into the mechanisms underlying nonpainful versus painful DD, human cerebrospinal fluid (CSF) was examined using differential expression shotgun proteomic techniques comparing healthy control participants, subjects with nonpainful DD, and patients with painful DD scheduled for spinal fusion surgery. ⋯ Cystatin C and hemopexin were selected for further examination using enzyme-linked immunosorbent assay in a larger cohort. While cystatin C correlated with DD severity but not pain or disability, hemopexin correlated with pain intensity, physical disability, and DD severity. This study shows that CSF can be used to study mechanisms underlying painful DD in humans, and suggests that while painful DD is associated with nerve injury, inflammation itself is not sufficient to develop LBP.
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Sickle cell disease (SCD) is associated with episodes of severe vaso-occlusive pain beginning in infancy with a subset of patients with SCD transitioning to chronic pain. Response to experimental pain using quantitative sensory testing in these patients suggests altered pain processing. The objectives of this study were to characterize sensitivity to multiple modalities of experimental pain stimuli and to interrogate the relationship of psychological covariates, clinical pain burden, and pain-related outcomes to experimental pain sensitivity in children with SCD compared with healthy individuals of similar age and sex. ⋯ Anxiety, depressive symptoms, catastrophizing, and somatization were found to be associated with increased sensitivity to experimental pain stimuli. Increased frequency of painful episodes in SCD was associated with decreased sensitivity to heat pain and decreased mechanical temporal summation. These data suggest that careful consideration be given to psychological factors, age, sex, and clinical burden of pain when studying response to experimental pain in SCD.
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Review Meta Analysis
The relationship between Pacing and Avoidance in Chronic Pain: A Systematic Review and Meta-analysis.
Activity pacing is ubiquitous in chronic pain management and aims to reduce pain-contingent avoidance of activity to improve functioning. A meta-analysis, however, has linked pacing with higher levels of pain and disability. One potential explanation is an overlap between existing measures of pacing and avoidance, leading to links with poorer outcomes that are typically associated with avoidance. This study systematically reviews the evidence regarding the relationship between measures of pacing and avoidance. A search was conducted for studies measuring both constructs in adults with chronic pain. A meta-analysis of correlations between pacing and avoidance was conducted; 16 studies were included and a small positive correlation was found (r = .290, P < .001) overall. Single-item and multiple-item measures were also compared; a moderate positive correlation was found for multiple-item measures (r = .410, P < .001), which differed significantly from a small positive correlation found for single-item measures (r = .105, P < .001). Due to limited studies, independent analyses of individual subscales were not possible. Existing measures of pacing-particularly multiple-item measures-may partially confound pacing with avoidance. Further research is required to ensure that a reliable measure of pacing that distinguishes this construct from avoidance is available to adequately evaluate pacing instruction and the effect of pacing on key outcomes in chronic pain. ⋯ This meta-analysis examines the correlation between pacing and avoidance in adults with chronic pain. Results indicate that existing measures may partially confound pacing with avoidance. Directions for future research are proposed to ensure that an adequate measure of pacing exists to evaluate its effect on key outcomes in chronic pain.
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Half of children admitted after surgery experience intense pain in hospital, and many experience continued pain and delayed functional recovery at home. However, there is a gap in tools available to measure acute functional ability in pediatric postsurgical settings. We aimed to validate the Youth Acute Pain Functional Ability Questionnaire (YAPFAQ) in a large inpatient pediatric surgical population, evaluate its responsiveness to expected functional recovery, and develop a short form for broad clinical implementation. The YAPFAQ is a self-report measure assessing acute functional ability, developed in children admitted for acute sickle cell pain. We evaluated psychometric properties of the measure in 564 children ages 8 to 18 years admitted after surgery. A sample of 54 participants completed the YAPFAQ daily for 3 days after major surgery to assess responsiveness. The measure showed good reliability (Cronbach α = .96) and construct validity, with expected relationships with physical health-related quality of life (r = -.53, P < .001) and pain intensity (r = .42, P < .001). YAPFAQ scores decreased over time showing good responsiveness to expected recovery. A 3-item short form of the YAPFAQ showed promising psychometric properties. Early assessment of functioning after surgery may identify children at risk for poor functional outcomes and allow targeting of therapies to improve postsurgical recovery. ⋯ The YAPFAQ showed promising psychometric properties in a pediatric postsurgical population. This study addresses a gap in tools available to monitor functional recovery during hospitalization after pediatric surgery. Early detection of problems with recovery may enable targeted therapies to improve postsurgical outcomes.
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Few studies have examined the underlying psychosocial mechanisms of pain in Asian Americans. Using the biopsychosocial model, we sought to determine whether variations in depression contribute to racial group differences in symptomatic knee osteoarthritis pain between Asian Americans and non-Hispanic white Americans. The sample consisted of 100 participants, including 50 Asian Americans (28 Korean Americans, 9 Chinese Americans, 7 Japanese Americans, 5 Filipino Americans, and 1 Indian American) and 50 age- and sex-matched non-Hispanic white Americans with symptomatic knee osteoarthritis pain. The Centers for Epidemiologic Studies Depression Scale was used to assess symptoms of depression, and the Western Ontario and McMaster Universities Osteoarthritis Index and the Graded Chronic Pain Scale were used to measure clinical pain. In addition, quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically-induced pain. The results indicated that higher levels of depression in Asian Americans may contribute to greater clinical pain and experimental pain sensitivity. These findings add to the growing literature regarding ethnic and racial differences in pain and its associated psychological conditions, and additional research is warranted to strengthen these findings. ⋯ This article shows the contribution of depression to clinical pain and experimental pain sensitivity in Asian Americans with knee osteoarthritis. Our results suggest that Asian Americans have higher levels of depressive symptoms and that depression plays a relevant role in greater clinical pain and experimental pain sensitivity in Asian Americans.