Saturday, August 31, 2013
Epidural Analgesia vs. PCA in Adolescent Scoliosis Surgery
Post-operative analgesia is a major challenge for adolescent idiopathic scoliosis (AIS) patients undergoing long fusions for deformity. There is a constant tension between providing adequate analgesia that allows for early mobilization and causing side effects related to the analgesic. Recently, continuous epidural analgesia (CEA) has been developed as an alternative to patient controlled IV-analgesia (PCA) in order to minimize the systemic effects of narcotics. Dr. Klatt and his colleagues in Utah performed a non-blinded randomized controlled trial comparing the effectiveness and side-effect profile of three post-operative analgesia regimens for patients undergoing long posterior fusion surgery for AIS: PCA, single CEA (i.e. one epidural catheter placed in the center of the construct), and double CEA (i.e. two epidural catheters evenly spaced over the construct). They found that the double CEA patients had significantly lower pain scores (i.e. mean of 3.6 vs. 4.2 for PCA and 4.1 for single CEA). There were no major side effects or complications attributed to the analgesia regimens (i.e. infection, respiratory depression), and the single CEA group had the lowest rate of complications, though there were no significant differences in complication rates across the groups. Pruritis, nausea, and constipation were the most common side effects. There were no differences in time to ambulation or length of stay.
The authors should be commended for performing a high quality, level 1 RCT studying an important clinical question. Based on their results, they changed their practice such that double CEA is now the standard post-operative analgesia regimen at their institution. In order to determine if this regimen should be widely adopted, further data about possible complications and costs are necessary. While the authors powered their study to detect a 0.5 point difference in pain scores, the study is underpowered to detect and compare rare complications. If a rare but serious complication (i.e. epidural infection, respiratory failure) occurs at a rate of 1%, thousands of patients would likely be required to compare complication rates among the groups. Thus, the current study does not provide much data about the safety of these regimens. Additionally, the benefit of double CEA vs. PCA was quite modest (i.e. less than 1 point on a 10 point pain scale), and it is unclear if such a benefit justifies the increased cost that likely accompanies this technique. Continuous epidural analgesia seems to hold promise as a safe, effective post-operative pain regimen in AIS, and this study provides good data demonstrating that it might offer a modest benefit vs. PCA. Hopefully large studies in the future will better determine its safety profile and cost-effectiveness.
Please read Dr. Klatt’s article on this topic in the September 1 issue. Will this study push you towards using CEA? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor