Pain
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Comparative Study
5alpha-reduced neuroactive steroids alleviate thermal and mechanical hyperalgesia in rats with neuropathic pain.
5alpha-reduced neuroactive steroids with selective modulatory action in vitro on T or combined modulatory action on T and GABA(A) currents present in peripheral sensory neurons have been shown to induce potent peripheral analgesia in vivo in intact animals. Although the role of T and GABA(A) currents in pathophysiology of neuropathic pain (NPP) is not established, it appears that blockade of T currents and/or potentiation of GABA(A) currents could be beneficial in the management of NPP. To study the potential usefulness of 5alpha-reduced neuroactive steroids in alleviating NPP, we selected two newly synthesized steroids-ECN and CDNC24-with a selective blocking effect on T currents and a selective potentiating effect on GABA(A) currents, respectively, and commercial analogs-alphaxalone and 3alpha5alphaP-with the effects on both ion channels. ⋯ We found that 5alpha-reduced neuroactive steroids alleviate thermal and mechanical hyperalgesia in NPP rats. ECN and CDNC24 were more selective in alleviating thermal nociception in NPP than in sham animals when compared to 3alpha5alphaP and alphaxalone although the anti-nociceptive effect induced by 3alpha5alphaP and alphaxalone was more profound. CDNC24 was most selective since it had very minimal anti-nociceptive effect in sham animals but a very profound anti-nociceptive effect in NPP animals suggesting that, under pathological conditions, peripheral GABA(A) receptors might be an attractive therapeutic target.
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Randomized Controlled Trial Comparative Study
Brief cognitive-behavioral therapy for temporomandibular disorder pain: effects on daily electronic outcome and process measures.
We used patient daily electronic ratings of outcome (activity interference, pain intensity, jaw use limitations, negative mood) and process (pain-related beliefs, catastrophizing, and coping) variables to evaluate a brief cognitive-behavioral (CB) treatment for chronic temporomandibular disorder (TMD) pain. TMD clinic patients (N=158) were assigned randomly to four biweekly sessions of either CB pain management training (PMT) or an education/attention control condition [self-care management (SCM)] and were asked to complete electronic interviews three times daily for the 8-week treatment. We analyzed diary data from 126 participants who completed >50% of requested interviews for >6 weeks. ⋯ This study is novel in its application of electronic diary methods for assessing outcome and process variables in a chronic pain treatment trial, and supports the feasibility and utility of such methods. The brief CB treatment was efficacious in decreasing catastrophizing and increasing perceived control over pain, and in improving activity interference and jaw use limitations for a subgroup of patients. Longer-term follow-ups are ongoing to determine if there is an impact on outcomes over time.
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Comparative Study
The measurement of postoperative pain: a comparison of intensity scales in younger and older surgical patients.
The psychometric properties of pain intensity scales for the assessment of postoperative pain across the adult lifespan have not been reported. The objective of this study was to compare the feasibility and validity of the Numeric Rating Scale (NRS), Verbal Descriptor Scale (VDS), and Visual Analog Scale (horizontal (VAS-H) and vertical (VAS-V) line orientation) for the assessment of pain intensity in younger and older surgical patients. At 24h following surgery, 504 patients, who were receiving i.v. morphine via patient-controlled analgesia, completed the pain intensity measures and the McGill Pain Questionnaire (MPQ) in a randomized order. ⋯ The VDS also had a favourable profile with low error rates and good face, convergent and criterion validity. Finally, difficulties with VAS use among the elderly were identified, including high rates of unscorable data and low face validity. Its use with elderly postoperative patients should be discouraged.
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Randomized Controlled Trial Comparative Study
The association between negative affect and opioid analgesia in patients with discogenic low back pain.
Comprised mainly of depression, anxiety, and high neuroticism, psychopathology diminishes the effectiveness of many chronic pain treatments. But, it is not known if it is associated with diminished opioid analgesia in patients with chronic, noncancer pain. We tested the hypothesis that psychopathology diminishes opioid analgesia in patients with discogenic low back pain in 60 patients not on opioids in a double blind, placebo controlled, random crossover designed trial. ⋯ A morphine minus placebo analgesia calculation revealed 59.2% TOTPAR in the LOW group vs. 21.7% in the HIGH group, P=.0001. High levels of psychopathology are associated with diminished opioid analgesia in patients with discogenic low back pain. These results have implications for the prescription of oral opioids to patients with chronic low back pain and psychopathology.
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This paper develops a prognostic approach to defining chronic back pain. Possible and probable chronic back pain were defined, respectively, by a 50% and an 80% (or greater) probability of future clinically significant back pain. We assessed whether an empirically derived chronic pain classification satisfied these validating criteria among 1213 primary care back pain patients assessed at baseline and at 1, 2 and 5 year follow-ups. ⋯ At baseline and 1 year, 6.1 and 4.4% of study patients met or exceeded the 80% risk threshold for probable chronic back pain. An additional 20.3% at baseline and 12.5% at 1 year met or exceeded the 50% risk threshold for possible chronic back pain. Defining chronic pain prospectively, by risk thresholds for future clinically significant pain, provides an empirically grounded approach to chronic pain assessment.