European journal of pain : EJP
Randomized Controlled Trial
Why is this significant?
This is the first randomised controlled trial looking at the impact of perioperative ketamine on persistent post-surgical (PPS) pain 1 year after thoracic surgery. Thoracotomy is associated with both severe and a high incidence (up to 50% at 6 months) chronic pain.
Ketamine has important analgesic properties through NMDA blockade, and has been long thought (hoped) that via this it may modify chronic post-surgical pain. Nonetheless, many studies have been unable to show a benefit for ketamine in reducing PPS pain.
What did they show?
Chumbley et al. ran ketamine infusions at 0.1 mg/kg/hour for 96 hours in patients undergoing thoracotomy, starting with a 0.1 mg/kg bolus 10 minutes before surgery. Patients also received either an epidural or paravertebral infusion for post-operative analgesia.
Although there were small differences in acute pain (notably the ketamine group used less PCA morphine) there was no difference in persistent post-surgical pain at 12 months.
The evidence continues to mount against perioperative ketamine, suggesting it does not reduce persistent post-surgical pain, not-withstanding its acute analgesia benefits. Await results of the ROCKet trial (Reduction Of Chronic Post-surgical Pain with Ketamine) to provide greater clarity...
Notably, the researchers did demonstrate a dramatically lower incidence of PPS pain than for similar studies (27%, 18%, 13% at 3, 6, 12 months) across both the ketamine and placebo group. This suggests that either the study participants were not representative of the typical thoracotomy patient (unlikely), or other care associated with the study had a beneficial effect on reducing PPS – perhaps even via a Hawthorne-like effect.summary
It would be desirable to identify patients with acute low back pain (ALBP) who are at high risk for transition to chronic pain early in the course of their disease. This would enable early preventive or therapeutic interventions. Patients with chronic low back pain (CLBP) display signs of central hypersensitivity. This may contribute to the transition to CLBP. We tested the hypothesis that central hypersensitivity as assessed by quantitative sensory tests predicts transition to CLBP. ⋯ We found no evidence to support a clinically relevant ability of current quantitative sensory tests to predict the transition from acute to CLBP.
Controlled Clinical Trial
This article presents the results of a parallel-group, non-randomized, controlled study that evaluated the feasibility of an online training program for improving observer detection of facial pain expression. ⋯ The index of facial pain expression (IFPE) is an online training program that can improve an observer's ability to reliably detect expressions of clinical pain after as few as 3.5-hr of training.
Primary dysmenorrhoea (PDM), characterized as menstrual pain without pelvic pathology, is associated with pain-related negative mood and hormone fluctuations. Previous studies strongly supported the link between pain and negative mood in affected individuals; however, it remains largely unknown in patients with PDM. ⋯ Our findings provide further evidence of amygdala-related abnormalities, which may be associated with pain-related affective distress and hormonal fluctuations in women with PDM, and complement the brain mechanism investigations for the pathophysiology of PDM.