The journal of pain : official journal of the American Pain Society
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Comparative Study
Comparative responsiveness of verbal and numerical rating scales to measure pain intensity in patients with chronic pain.
Verbal rating scale (VRS) and numerical rating scale (NRS) are regularly used to assess and monitor pain in chronic pain patients. Although the NRS has been generally preferred, limited comparative responsiveness evidence was reported. This study compared the responsiveness of VRS and NRS measuring current pain and investigated the influence of different references (ie, worst, least, average, and current pain or their composite) on the NRSs' responsiveness. Two hundred fifty-four chronic pain patients attended a 10-day pain self-management program and were assessed with two 6-point VRSs (assessing current pain) and four 11-point NRSs (assessing worst, least, average, and current pain) at pre- and posttreatment. A patient-reported rating of pain improvement was used as the criterion for standardized response mean and receiver operating characteristic curve analyses. Results showed that the VRSs and NRSs exhibited small responsiveness in all patients, but the magnitude of responsiveness became moderate to large in patients with improved pain. However, in patients with pain improvements, the NRS current pain item and composite score (made up of the 4 pain items) were found to have significantly larger responsiveness and greater discriminatory ability to detect the presence of improvement than other current pain VRSs and the NRSs assessing worst, least, and average pain. Potential implications for clinical practice are discussed. ⋯ This study shows that the current pain and composite NRSs were more responsive than the current pain VRSs and the NRSs measuring other individual pain references in patients with improved pain, undertaking a short-term, self-management program. The results help inform the selection of pain intensity measures in studies using similar types of intervention.
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Factors contributing to pain following surgery are poorly understood, with previous research largely focused on adults. With approximately 6 million children undergoing surgery each year, there is a need to study pediatric persistent postsurgical pain. The present study includes patients with adolescent idiopathic scoliosis undergoing spinal fusion surgery enrolled in a prospective, multicentered registry examining postsurgical outcomes. The Scoliosis Research Society Questionnaire-Version 30, which includes pain, activity, mental health, and self-image subscales, was administered to 190 patients prior to surgery and at 1 and 2 years postsurgery. A subset (n = 77) completed 5-year postsurgery data. Pain prevalence at each time point and longitudinal trajectories of pain outcomes derived from SAS PROC TRAJ were examined using analyses of variance and post hoc pairwise analyses across groups. Thirty-five percent of patients reported pain in the moderate to severe range presurgery. One year postoperation, 11% reported pain in this range, whereas 15% reported pain at 2 years postsurgery. At 5 years postsurgery, 15% of patients reported pain in the moderate to severe range. Among the 5 empirically derived pain trajectories, there were significant differences on self-image, mental health, and age. Identifying predictors of poor long-term outcomes in children with postsurgical pain may prevent the development of chronic pain into adulthood. ⋯ This investigation explores the prevalence of pediatric pain following surgery, up to 5 years after spinal fusion surgery. Five pain trajectories were identified and were distinguishable on presurgical characteristics of age, mental health, and self-image. This is the largest study to examine longitudinal pediatric pain trajectories after surgery.
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Several studies have reported reduced cerebral gray matter (GM) volume or density in chronic pain conditions, but there is limited research on the plasticity of the human cortex in response to psychological interventions. We investigated GM changes after cognitive-behavioral therapy (CBT) in patients with chronic pain. We used voxel-based morphometry to compare anatomic magnetic resonance imaging scans of 13 patients with mixed chronic pain types before and after an 11-week CBT treatment and to 13 healthy control participants. CBT led to significant improvements in clinical measures. Patients did not differ from healthy controls in GM anywhere in the brain. After treatment, patients had increased GM in the bilateral dorsolateral prefrontal, posterior parietal, subgenual anterior cingulate/orbitofrontal, and sensorimotor cortices, as well as hippocampus, and reduced GM in supplementary motor area. In most of these areas showing GM increases, GM became significantly higher than in controls. Decreased pain catastrophizing was associated with increased GM in the left dorsolateral prefrontal and ventrolateral prefrontal cortices, right posterior parietal cortex, somatosensory cortex, and pregenual anterior cingulate cortex. Although future studies with additional control groups will be needed to determine the specific roles of CBT on GM and brain function, we propose that increased GM in the prefrontal and posterior parietal cortices reflects greater top-down control over pain and cognitive reappraisal of pain, and that changes in somatosensory cortices reflect alterations in the perception of noxious signals. ⋯ An 11-week CBT intervention for coping with chronic pain resulted in increased GM volume in prefrontal and somatosensory brain regions, as well as increased dorsolateral prefrontal volume associated with reduced pain catastrophizing. These results add to mounting evidence that CBT can be a valuable treatment option for chronic pain.
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Observational Study
Clinical orofacial characteristics associated with risk of first-onset TMD: the OPPERA prospective cohort study.
Case-control studies have documented clinical manifestations of chronic temporomandibular disorder (TMD), whereas clinical predictors of TMD development are largely unknown. We evaluated 41 clinical orofacial characteristics thought to predict first-onset TMD in a prospective cohort study of U.S. adults aged 18 to 44 years. During the median 2.8-year follow-up period, 2,737 people completed quarterly screening questionnaires. Those reporting symptoms were examined and 260 people were identified with first-onset TMD. Univariate and multivariable Cox regression models quantified associations between baseline clinical orofacial measures and TMD incidence. Significant predictors from baseline self-report instruments included oral parafunctions, prior facial pain and its life-impact, temporomandibular joint noises and jaw locking, and nonspecific orofacial symptoms. Significant predictors from the baseline clinical examination were pain on jaw opening and pain from palpation of masticatory, neck, and body muscles. Examiner assessments of temporomandibular joint noise and tooth wear facets did not predict incidence. In multivariable analysis, nonspecific orofacial symptoms, pain from jaw opening, and oral parafunctions predicted TMD incidence. The results indicate that only a few orofacial examination findings influenced TMD incidence, and only to a modest degree. More pronounced influences were found for self-reported symptoms, particularly those that appeared to reflect alterations to systems beyond the masticatory tissues. ⋯ OPPERA's prospective cohort study identifies predictors of first-onset TMD comprising self-reported orofacial symptoms and examination findings. The results suggest a complex pattern of TMD etiology that is influenced by disorders locally, in masticatory tissues, and systemically, in pain-regulatory systems.
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Observational Study
Summary of findings from the OPPERA prospective cohort study of incidence of first-onset temporomandibular disorder: implications and future directions.
Papers in this issue investigate when and how putative risk factors influence development of first-onset, painful temporomandibular disorder (TMD). The results represent first findings from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study that monitored 2,737 men and women aged 18 to 44 years recruited at 4 U.S. study sites. During a median 2.8-year follow-up period, 260 participants developed TMD. The average incidence rate of 4% per annum was influenced by a broad range of phenotypic risk factors including sociodemographic characteristics, health status, clinical orofacial factors, psychological functioning, pain sensitivity, and cardiac autonomic responses. A novel method of multivariable analysis used random forest models to simultaneously evaluate contributions of all 202 phenotypic variables. Variables from the health status domain made the greatest contribution to TMD incidence, followed closely by psychological and clinical orofacial domains. However, only a few measures of pain sensitivity and autonomic function contributed to TMD incidence, and their effects were modest. Meanwhile, age and study site were independent predictors of TMD incidence, even after controlling for other phenotypes. Separate analysis of 358 genes that regulate pain found several novel genetic associations with intermediate phenotypes that, themselves, are risk factors for TMD, suggesting new avenues to investigate biological pathways contributing to TMD. ⋯ Collectively, the papers in this issue demonstrate that TMD is a complex disorder with multiple causes consistent with a biopsychosocial model of illness. It is a misnomer and no longer appropriate to regard TMD solely as a localized orofacial pain condition.