ABSTRACT: Recent randomized controlled trials comparing the efficacy between intraoperative methadone and other opioids on postoperative outcomes have been limited by their small sample sizes and conflicting results. We performed a meta-analysis on randomized controlled trials which investigated outcomes between methadone and an opioid control group. Primary outcome data included postoperative opioid consumption, number of patients who received postoperative opioids, time to first analgesic, and pain scores. Secondary outcomes included time to extubation and incidence of nausea, vomiting, and respiratory depression. Statistical analysis was performed using RevMan. A P < 0.05 was considered statistically significant. Nine studies comprising 632 patients were included. There was no statistically significant reduction in opioid consumption postoperatively between the groups. Forty-seven percentage of patients in the methadone group received a dose of opioid postoperatively compared with 55% in the other opioids control group, which was not statistically significant. (P = 0.25) There was no difference in average time to receiving first postoperative analgesic among the groups. Pain scores within 24 hours were significantly lower in the methadone group when compared with other opioids (8 studies, n = 622, -0.49 [-0.74, -0.23], P = 0.002). However, there was no difference between 24 and 72 hours. There was no difference among the groups with respect to extubation time, nausea, vomiting, or respiratory depression. This meta-analysis concludes that there is currently insufficient evidence for the use of intraoperative methadone, when compared with other opioids. Although there was a decrease in average pain scores with methadone when compared with controls at 24 hours, there was no difference between 24 and 72 hours.
The focus of post-operative pain management for neurosurgeons should be on avoiding opioids as much as possible due to obvious reasons. In my practice, opioids are never used after craniotomies and sparingly used after spine surgeries for a maximum of 2 to 3 days post op. Therefore, this article is of no interest to neurosurgeons in several parts of the world who follow pain management protocols which do not rely on opioids.
In my setting, we tend not to use opiates if we can, and we would not use methadone. Stick with the tried and tested!
Interesting summary with, however, many variations compared to the one published in 2019 (Anesth Analg 2019; 129: 1723-1732) Limits: - The absence of TSA to rule out a type 1 and, above all, type II error inherent in meta-analyzes involving few patients - The absence of sensitivity analysis according to the risk of bias of the studies and according to the analgesic modalities used in each study (intravenous lidocaine, regional analgesia, NSAIDs, etc.)
We had high hopes for methadone as an opioid-sparing mixed agent (opioid/non-opioid) in surgical patients. The results of this analysis make it clear that methadone has limited advantage over other opioids.
Recent trends in Neuroanesthesia favor reducing opioids, which is easier in brain surgery than in spinal surgery. This meta analysis includes at least 3 RCTs based in spinal and orthopedic surgeries, which seem to favor methadone use; although, the final conclusion of the paper is that there is no significant evidence to support the use of intraoperative methadone to decrease postoperative opioid requirements. We still need more RCTs to run.
I was not aware of methadone being used intra-operatively for pain relief. While I am not a fan of meta-analyses, this study seemed to show no significant benefit from its use during surgery.
This is a well conducted systematic review; however, it offers an inconclusive answer.
According to the authors, pain scores within 24 hours were significantly lower in the methadone group when compared with other opioids (8 studies, n 5 622, 20.49 [20.74, 2 0.23], P 5 0.002). Further studies are needed to confirm this result.