European journal of pain : EJP
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Randomized Controlled Trial
Ketamine infusion for 96 hr after thoracotomy: Effects on acute and persistent pain.
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.
Bottom-line
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...
An afterthought
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 -
Within the Fear Avoidance Model of pain, quantitative neurophysiological factors provide additional conceptual benefit when integrated along with traditional psychologically aspects of the FAM.
pearl -
Randomized Controlled Trial
The effect of total intravenous anaesthesia with propofol on postoperative pain after third molar surgery: a double blind randomized controlled trial.
Total intravenous anaesthesia (TIVA) with propofol may reduce pain after surgery compared with inhalational anaesthetic techniques. Whether propofol provides analgesic benefit may be influenced by the surgical procedure and anaesthetic/analgesic regime. Third molar surgery is a consistent and fairly standard surgical technique that provides a good model for postoperative pain. We investigated whether propofol TIVA or sevoflurane (SEVO) inhalational anaesthesia would produce better quality pain relief after third molar surgery. ⋯ Choice of general anaesthetic technique can affect postoperative analgesia. The results of this study suggest that propofol TIVA improves postoperative pain and patient satisfaction after third molar surgery compared to inhalational anaesthesia.
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Review Meta Analysis
The effectiveness of self-management interventions in adults with chronic orofacial pain: A Systematic review, Meta-analysis and Meta-regression.
Psychosocial risk factors associated with chronic orofacial pain are amenable to self-management. However, current management involves invasive therapies which lack an evidence base and has the potential to cause iatrogenic harm. ⋯ This systematic review provides clear evidence for effectiveness of combined biomedical and psychological interventions (incorporating self-management approaches) on long-term outcomes in the management of chronic orofacial (principally TMD) pain. Self-management should be a priority for early intervention in primary care in preference to invasive, irreversible and costly therapies. Further research is needed firstly to clarify the relative effectiveness of specific components of self-management, both individually and in conjunction, and secondly on outcomes in other types of chronic orofacial pains.
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Randomized Controlled Trial
Rewarded placebo analgesia: A new mechanism of placebo effects based on operant conditioning.
Placebo analgesia is explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. We aimed to induce placebo analgesia by operant conditioning. ⋯ According to the current placebo literature, placebo analgesia can be explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. Our study reveals that patients can learn placebo analgesia as a result of operant conditioning, suggesting that randomized controlled trials could be improved by controlling the reinforcement that might occur spontaneously when patients interact with, for example, medical personnel.