Pain
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Randomized Controlled Trial
Randomized controlled trial of intrathecal oxytocin on speed of recovery after hip arthroplasty.
Recovery from surgery is quicker in the postpartum period, and this may reflect oxytocin action in the spinal cord. We hypothesized that intrathecal injection of oxytocin would speed recovery from pain and disability after major surgery. Ninety-eight individuals undergoing elective total hip arthroplasty were randomized to receive either intrathecal oxytocin (100 μg) or saline. ⋯ In planned secondary analyses, postoperative opioid use ended earlier in the oxytocin group and oxytocin-treated patients walked nearly 1000 more steps daily at 8 weeks ( P < 0.001) and exhibited a clinically meaningful reduction in disability for the first 21 postoperative days ( P = 0.007) compared with saline placebo. Intrathecal oxytocin before hip replacement surgery does not speed recovery from worst daily pain. Secondary analyses suggest that further study of intrathecal oxytocin to speed functional recovery without worsening pain after surgery is warranted.
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Randomized Controlled Trial
Dose-response relationship and effect modifier of stabilisation exercises in nonspecific low back pain: a project-wide individual patient data re-analysis on 1483 intervention participants.
This planned MiSpEx-Network reanalysis was designed to derive a dose-response relationship under consideration of further effect modifiers in exercises on low back pain. One thousand four hundred eighty three intervention participants with low back pain (mean age, 40.9 years [SD 14 years]) performed stabilisation exercises (3 weeks supervised, 9 weeks self-administered). Patients reported pain intensity, disability, and disability days at baseline, 3 weeks, 12 weeks, and 6 months post randomisation. ⋯ The odds ratio for a clinically important effect with higher exercise frequencies decreased at 3 weeks (OR = 0.71 [0.618-0.813] for >2.5*week -1 ) and increased at 12 weeks (1.13 [1.006-1.270], >1.5*week -1 ). Using longer intervention durations, adding a perturbation component to the stabilisation trainings and using higher frequencies (up to a certain point) may lead to an even more beneficial response on exercise in patients with low back pain. Developing strategies to maintain a training frequency of at least 2 times per week may be relevant in stabilisation exercises to treat low back pain.
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A multisystem phenotype with the Triad of bodily pain, psychological distress, and sleep disturbance was found to have high risk for developing initial onset of painful temporomandibular disorders (TMDs) in the multicenter Orofacial Pain: Prospective Evaluation and Risk Assessment dataset. In this study, we systemically examined phenotypic characteristics and explored potential pathophysiology in quantitative sensory testing and autonomic nervous system domains in this multisystem Triad phenotype. Secondary analysis was performed on 1199 non-Triad and 154 Triad TMD-free Orofacial Pain: Prospective Evaluation and Risk Assessment enrollees at baseline. ⋯ These findings highlight the importance of whole-person multisystem assessment at the stage before developing complex pain conditions, such as TMDs, and suggest that, in addition to a "tissue damage monitor," pain should be considered in a broader context, such as a component within a "distress monitoring system" at the whole-person level when multisystem issues copresent. Therefore, the presence or absence of multisystem issues may carry critical information when searching for disease mechanisms and developing mechanism-based intervention and prevention strategies for TMDs and related pain conditions. Cardiovascular autonomic function should be further researched when multisystem issues copresent before developing TMDs.
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Open-label placebos, or placebos without deception, have been found to induce analgesia, a challenging concept that need to be investigated in detail. In particular, what we need to know is the mechanism through which analgesia is induced when no deception is involved. In this study, we show for the first time that open-label placebo analgesia can be reversed by the opioid antagonist naloxone, as already shown for deceptive placebos. ⋯ In these responders, we found that a hidden injection of 10 mg naloxone could reverse placebo analgesia compared with a hidden injection of saline solution. At least 2 control groups showed that naloxone per se was not hyperalgesic, thus ruling out naloxone-induced hyperalgesia as a confounding variable. In light of the need to better understand open-label placebo effects, these findings represent the first experimental evidence that nondeceptive placebo analgesia may be mediated by the same mechanisms as deceptive placebo analgesia, namely the endogenous opioid systems.