Pain
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Approximately thirty-four percent of people who experience acute low back pain (LBP) will have recurrent episodes. It remains unclear why some people experience recurrences and others do not, but one possible cause is a loss of normal control of the back muscles. We investigated whether the control of the short and long fibres of the deep back muscles was different in people with recurrent unilateral LBP from healthy participants. ⋯ The short fibres were active earlier than long fibres on both sides in the healthy participants (p<0.001) and on the non-painful side in the LBP group (p=0.045), but not on the previously painful side in the LBP group. Activity of deep back muscles is different in people with a recurrent unilateral LBP, despite the resolution of symptoms. Because deep back muscle activity is critical for normal spinal control, the current results provide the first evidence of a candidate mechanism for recurrent episodes.
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Intense stress and fear have long been known to give rise to a suppression of pain termed "stress-induced analgesia", mediated by brainstem pain-modulating circuitry, including pain-inhibiting neurons of the rostral ventromedial medulla. However, stress does not invariably suppress pain, and indeed, may exacerbate it. Although there is a growing support for the idea of "stress-induced hyperalgesia", the neurobiological basis for this effect remains almost entirely unknown. ⋯ In addition to the expected increases in body temperature and heart rate, disinhibition of the DMH induced a robust activation of ON-cells, suppression of OFF-cell firing and behavioral hyperalgesia. Blocking ON-cell activation prevented hyperalgesia, but did not interfere with DMH-induced thermogenesis or tachycardia, pointing to differentiation of neural substrates for autonomic and nociceptive modulation within the RVM. These data demonstrate a top-down activation of brainstem pain-facilitating neurons, and suggest a possible neural circuit for stress-induced hyperalgesia.
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Randomized Controlled Trial
A randomized, placebo-controlled trial of oxycodone and of gabapentin for acute pain in herpes zoster.
Although acute pain in patients with herpes zoster can be severe and has a substantial impact on health-related quality of life, there have been no randomized clinical trials of oral medications specifically for its ongoing treatment. A randomized clinical trial was conducted in which 87 subjects >or=50 years of age with herpes zoster within 6 calendar days of rash onset and with worst pain in the past 24h >or=3 on a 0-10 rating scale initiated 7 days of treatment with famciclovir in combination with 28 days of treatment with either controlled-release (CR) oxycodone, gabapentin, or placebo. Subjects were evaluated for adverse effects of treatment, acute pain, and health-related quality of life. ⋯ Treatment with CR-oxycodone reduced the mean worst pain over days 1-8 (p=0.01) and days 1-14 (p=0.02) relative to placebo but not throughout the entire 28-day treatment period as pain resolved in most subjects. Gabapentin did not provide significantly greater pain relief than placebo, although the data for the first week were consistent with a modest benefit. By demonstrating that CR-oxycodone is safe, generally adequately tolerated, and appears to have efficacy for relieving acute pain, the results of this clinical trial provide a foundation for evidence-based treatment for acute pain in herpes zoster.
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Randomized Controlled Trial Clinical Trial
Cost effectiveness of two rehabilitation programmes for neck and back pain patients: A seven year follow-up.
The cost effectiveness of work-oriented rehabilitation for persons on long-term sick leave needs to be assessed. This prospective observational study presents a follow-up seven years after rehabilitation using two different evidence-based work-oriented regimens. Individuals on sick leave for neck and back pain were referred to two rehabilitation programmes in Sweden. ⋯ The results of this study show that MPD but not OMTP achieves the goal of working life-oriented rehabilitation. A direct comparison between the rehabilitation programmes strengthened the assumption that long-term sickness absence prior to rehabilitation is associated with more days on sick leave after rehabilitation. This analysis also indicated the importance of participants' pain self-efficacy beliefs and recovery beliefs on rehabilitation outcome.