The journal of pain : official journal of the American Pain Society
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Multicenter Study Clinical Trial
The role of psychological factors in persistent pain after caesarean section.
This French multicenter prospective cohort study recruited 391 patients to investigate the risk factors for persistent pain after elective cesarean delivery, focusing on psychosocial aspects adjusted for other known medical factors. Perioperative data were collected and specialized questionnaires were completed to assess reports of pain at the site of surgery. Three dependent outcomes were considered: pain at the third month after surgery (M3, n = 268; risk = 28%), pain at the sixth month after surgery (M6, n = 239; risk = 19%), and the cumulative incidence (up to M6) of neuropathic pain, as assessed using the Douleur Neuropathique 4 questionnaire (n = 218; risk = 24.5%). The neuropathic aspect of reported pain changed over time in more than 60% of cases, pain being more intense if associated with neuropathic features. Whatever the dependent outcome, a high mental component of quality of life (SF-36) was protective. Pain at M3 was also predicted by pain reported during current pregnancy and a history of miscarriage. Pain at M6 was also predicted by report of a postoperative complication. Incident neuropathic pain was predicted by pain reported during current pregnancy, a previous history of a peripheral neuropathic event, and preoperative anxiety.
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Comparative Study
Latent Class Analysis of the Short and Long-Form of the Chronic Pain Acceptance Questionnaire- Further Examination of Patient Subgroups.
A substantial literature indicates that pain acceptance is a useful behavioral process in chronic pain rehabilitation. Pain acceptance consists of willingness to experience pain and to engage in important activities even in the presence of pain and is often measured using the Chronic Pain Acceptance Questionnaire (CPAQ). Previous traditional cluster analyses of the 20-item CPAQ identified 3 patient clusters that differed across measures of patient functioning in meaningful ways. The aims of this study were to replicate the previous study in a new sample, using the more robust method of latent class analysis (LCA), and to compare the cluster structure of the CPAQ and the shorter CPAQ-8. In total, 914 patients with chronic pain completed the CPAQ and a range of measures of psychological and physical function. Patient clusters identified via LCA were then used to compare patients across functional measures. Contrary to previous research, LCA demonstrated that a 4-cluster structure was superior to a 3-cluster structure. Consistent with previous research, cluster membership based on patterns of pain willingness and activity engagement was significantly associated with specific patterns of psychological and physical function, in line with theoretical predictions. These cluster structures were similar for both CPAQ-20 and CPAQ-8 items. These results provide further evidence of the relevance of chronic pain acceptance, and a more nuanced understanding of how the components of acceptance are related to function. ⋯ Pain acceptance is important in chronic pain. The findings of the present study, which included 914 individuals with chronic pain, provide support for 4 discrete groups of patients based on levels of acceptance (low, medium, and high), as well as a group with a high level of activity engagement and low willingness to have pain. These groups appear statistically robust and differed in predictable ways across measures of functioning.
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The Communal Coping Model of Pain Catastrophizing in Daily Life: A Within-Couples Daily Diary Study.
The Communal Coping Model characterizes pain catastrophizing as a coping tactic whereby pain expression elicits assistance and empathic responses from others. Married couples (N = 105 couples; 1 spouse with chronic low back pain) completed electronic daily diary assessments 5 times/day for 14 days. In these diaries, patients reported pain catastrophizing, pain, and function, and perceived spouse support, perceived criticism, and perceived hostility. Non-patient spouses reported on their support, criticism, and hostility directed toward patients, as well as their observations of patient pain and pain behaviors. Hierarchical linear modeling tested concurrent and lagged (3 hours later) relationships. Principal findings included the following: a) within-person increases in pain catastrophizing were positively associated with spouse reports of patient pain behavior in concurrent and lagged analyses; b) within-person increases in pain catastrophizing were positively associated with patient perceptions of spouse support, criticism, and hostility in concurrent analyses; c) within-person increases in pain catastrophizing were negatively associated with spouse reports of criticism and hostility in lagged analyses. Spouses reported patient behaviors that were tied to elevated pain catastrophizing, and spouses changed their behavior during and after elevated pain catastrophizing episodes. Pain catastrophizing may affect the interpersonal environment of patients and spouses in ways consistent with the Communal Coping Model. ⋯ Pain catastrophizing may represent a coping response by which individuals' pain expression leads to assistance or empathic responses from others. Results of the present study support this Communal Coping Model, which emphasizes interpersonal processes by which pain catastrophizing, pain, pain behavior, and responses of significant others are intertwined.
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Interactions between exogenous and endogenous opioids are not commonly investigated as a basis for sexually dimorphic opioid analgesia. We investigated the influence of spinal endomorphin 2 (EM2), an endogenous mu-opioid receptor (MOR) ligand, on the spinal antinociception produced by intrathecally administered opioids. Activation of spinal MORs facilitated spinal EM2 release. This effect was sexually dimorphic, occurring in males but not in females. Although activational effects of testosterone were required for opioid facilitation of spinal EM2 release in males, the absence of this facilitation in females did not result from either insufficient levels of testosterone or mitigating effects of estrogens. Strikingly, in males, the contribution of spinal EM2 to the analgesia produced by intrathecally applied MOR agonists depended on their analgesic efficacy relative to that of EM2. Spinal EM2 released by the higher efficacy MOR agonist sufentanil diminished sufentanil's analgesic effect, whereas EM2 released by the lower efficacy morphine had the opposite effect on spinal morphine antinociception. Understanding antithetical contributions of endogenous EM2 to intrathecal opioid antinociception not only enlightens the selection of opioid medications for pain management but also helps to explain variable sex dependence of the antinociception produced by different opioids, facilitating the acceptance of sexually dimorphic antinociception as a basic tenet. ⋯ The male-specific MOR-coupled enhancement of spinal EM2 release implies a parallel ability to harness endogenous EM2 antinociception. The inferred diminished ability of females to utilize the spinal EM2 antinociceptive system could contribute to their greater frequency and severity of chronic pain syndromes.