The journal of pain : official journal of the American Pain Society
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Chronic pain commonly accompanies long-term disabilities such as spinal cord injury (SCI). Research suggests that patient motivation to engage in adaptive pain coping strategies, such as exercise/stretching and task persistence, is an important factor in determining the impact that this pain will have on quality of life. One recently proposed model (the Motivational Model of Pain Self-Management) suggests that motivation to manage pain is influenced by 2 primary variables: Beliefs about the importance of engaging in pain self-management (ie, perceived importance) and beliefs about one's own ability to engage in these behaviors (ie, self-efficacy). The purpose of this study was to provide a preliminary test of this model in a sample of 130 adults with SCI who completed a return by mail survey. Measures included a numerical rating scale of pain intensity and the revised version of the Multidimensional Pain Readiness to Change Questionnaire. Mediation analyses were performed using multiple regression. Results suggested that the effects of perceived importance and self-efficacy on exercise behavior were mediated by readiness to engage in exercise, consistent with the proposed model. However, the model could not be established for the outcome of task persistence. ⋯ This study tests a model describing motivation to engage in pain management behaviors (ie, "readiness to change") in adults with SCI. This model could potentially aid clinicians in their conceptualization of the factors that affect patient motivation to manage pain.
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Symptoms of post-traumatic stress disorder (PTSD) are a common comorbidity in patients with a history of accident-related chronic pain and depression. However, little is known regarding the influence of PTSD in contributing to the affective distress, pain experience, and disability associated with chronic pain in this population. This study used structural equation modeling to examine 3 models that assess these relations in a sample of chronic pain patients with accident-related pain. Subjects were assessed for pain experience, depressive symptoms, anxiety, PTSD symptoms, pain disability, and relevant demographic variables. Pearson correlations indicated that symptoms of depression were significantly related to more severe pain, disability, and PTSD symptoms. PTSD symptoms were significantly associated with higher disability. The model of best fit indicated that after controlling for the influence of anxiety on the dependent measures, PTSD symptoms have a direct influence on severity of depressive symptoms, whereas depressive symptoms have a direct influence on pain intensity and an indirect impact on pain intensity by way of their effect on disability. These data point to the importance of unresolved PTSD symptoms in contributing to the level of depression, pain, and disability exhibited by chronic pain patients and highlight the need to consider directed and primary treatment of PTSD in pain rehabilitation programs. ⋯ This study highlights the impact of symptoms of PTSD on levels of depression, disability, and pain in patients with pain secondary to physical injury. Our results suggest that pain rehabilitation programs provide directed interventions for PTSD symptoms among this population to improve pain treatment outcomes.
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The role of specific nicotinic receptor (nAChR) subtypes in antinociception has not been fully elucidated because of the lack, until recently, of selective tool compounds. (R)-N-(1-azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl)thiopene-2-carboxamide) (compound B) is reported to be an agonist selective for the alpha(7)nAChR and in the present study was found to be efficacious in inflammatory pain models in 2 species. Compound B reversed complete Freund adjuvant-induced reductions in paw withdrawal thresholds in rat and mouse in a dose-related manner, producing maximum reversals of 65% +/- 4% at 10 mg/kg and 87% +/- 15% at 20 mg/kg. When rats and mice were predosed with the centrally penetrant, broad-spectrum nicotinic receptor antagonist mecamylamine, the efficacy of the agonist was significantly inhibited, producing reversals of only 11% +/- 5% at 10 mg/kg and 5% +/- 13% at 20 mg/kg, confirming activity via nicotinic receptors. Rats were also predosed systemically with the selective low-brain penetrant alpha(7)-antagonist methyllycaconitine, which had no effect on agonist activity (90% +/- 18% at 10 mg/kg), suggesting a central involvement. This hypothesis was further established with methyllycaconitine completely inhibited the agonist effect when dosed intrathecally (1% +/- 7%). ⋯ These studies provide good rationale for the utility of selective, central nervous system penetrant agonists at the alpha(7)-nicotinic receptor for the treatment of inflammatory pain.
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Randomized Controlled Trial
Hypoalgesic effect of the transcutaneous electrical nerve stimulation following inguinal herniorrhaphy: a randomized, controlled trial.
We investigated the effect of transcutaneous electrical nerve stimulation (TENS) for inguinal herniorrhaphy postoperative pain control in a prospective, randomized, double-blinded, placebo-controlled study. Forty patients undergoing unilateral inguinal herniorrhaphy with an epidural anesthetic technique were randomly allocated to receive either active TENS or placebo TENS. Postoperative pain was evaluated using a standard 10-point numeric rating scale (NRS). Analgesic requirements were also recorded. TENS (100 Hz, strong but comfortable sensory intensity) was applied for 30 minutes through 4 electrodes placed around the incision twice, 2 and 4 hours after surgery. Pain was assessed before and after each application of TENS and 8 and 24 hours after surgery. In the group treated with active TENS, pain intensity was significantly lower 2 hours (P = .028), 4 hours (P = .022), 8 hours (P = .006), and 24 hours (P = .001) after the surgery when compared with the group that received placebo TENS. Active TENS also decreased analgesic requirements in the postoperative period when compared with placebo TENS (P = .001). TENS is thus beneficial for postoperative pain relief after inguinal herniorrhaphy; it has no observable side effects, and the pain-reducing effect continued for at least 24 hours. Consequently, the routine use of TENS after inguinal herniorrhaphy is recommended. ⋯ This study presents the hypoalgesic effect of high-frequency TENS for postoperative pain after inguinal herniorrhaphy. This may reinforce findings from basic science showing an opioid-like effect provided by TENS, given that high-frequency TENS has been shown to activate delta-opioid receptors.
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The objectives of this study were to test the feasibility of measuring inflammatory and nociceptive biochemical mediators at the surgical site and to evaluate the relationship between wound and serum levels as well as determine any associations between mediator release, pain, and analgesic consumption after cesarean delivery. Twenty healthy women undergoing elective cesarean delivery with spinal anesthesia were enrolled. Wound exudate and serum mediators, pain scores, and analgesic consumption were measured at 1, 6, 24, and 48 hours after cesarean. In wound exudate, 19 of 20 mediators were reliably detected including interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, tumor necrosis factor-alpha, interferon-gamma, granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1beta), nerve growth factor (NGF), prostaglandin E2 (PG-E2), and substance P. Wound PG-E2 and various cytokines peaked early, whereas NGF showed a more delayed release. There were no correlations between the concentration versus time profile of wound and serum cytokines. Analgesic consumption during the first 24 hours after surgery was negatively correlated with IL-1beta, IL-6, and G-CSF in the wound exudate. This study demonstrates the feasibility of collecting and measuring nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between wound and serum levels emphasizes the importance of determining site-specific release if localized pathologies are to be studied. ⋯ This study demonstrates the feasibility of measuring real-time nociceptive and inflammatory mediators in surgical wounds. Our findings confirm the lack of correlation between wound and serum levels of many pro-inflammatory and anti-inflammatory cytokines and nerve growth factor.