Efficacy and safety of epidural anesthesia versus local anesthesia in percutaneous transforaminal endoscopic discectomy: a systematic review and meta-analysis

Background: For some patients, local anesthesia (LA) in percutaneous transforaminal endoscopic discectomy (PTED), especially during canal shaping and discectomy, is insufficient for analgesia. Epidural anesthesia (EA) is infrequently applied in PTED but reports satisfactory results. Previous studies present conflicting results in analgesia satisfactory and adverse events. Differences in surgery details and small sample size might explain conflicting results. Meta-analysis pools the results from individual studies to create a larger sample size and provides a more reliable conclusion. The aim of this study is to evaluate the efficacy and safety of EA in PTED. Methods: The search terms " percutaneous transforaminal endoscopic discectomy" and "anesthesia" are used to search Cochrane, Web of Science, PubMed, Embase, OVID, China National Knowledge Infrastructure (CNKI), VIP, and Wanfang from inception to 2021-08. Inclusion criteria is defined according to PICOS principals: P (patients): patients are diagnosed with lumbar disc herniation or spinal canal stenosis. I (intervention): patients undergo PTED under EA. C (comparisons): patients undergo PTED under LA. O (outcomes): primary outcomes: intraoperative visual analogue scale (VAS), anesthesia satisfactory, sufentanil usage. Secondary outcomes: adverse events, surgery exit, bleed volume, X-ray radiation. S (study design): randomized controlled trials (RCTs). The Cochrane RoB 2.0 is used to evaluate the quality of the included studies. Authors perform meta-analysis through Review Manager 5.4. Results: A total of 6 studies representing 529 patients are included: EA group includes 261 patients, and LA group includes 268 patients. All studies lack design of allocation concealment and blinding of participants and personnel. Only Luo reports blinding of outcome assessment in 2019. Meta analysis concludes that EA is superior in intraoperative analgesic [mean difference (MD) =-4.31; 95% confidence interval (CI): -4.52 to -4.09; P<0.00001], anesthesia satisfactory [odds ratio ( OR) =10.06; 95% CI: 2.41 to 41.98; P= 0.002], sufentanil usage (MD =-9.12; 95% CI: -10.34 to -7.90; P<0.00001), adverse events ( OR =0.19; 95% CI: 0.07 to 0.52; P=0.001). There is no difference in bleed volume (MD =-2.61; 95% CI: -5.45 to 0.23; P=0.07), exit rate (OR =0.23; 95% CI: 0.04 to 1.35; P=0.10) and future effects (MD =-0.23; 95% CI: -0.50 to 0.03; P=0.08). Discussion: EA is an effective and safe anesthesia method for PTED and might achieve better clinical results than LA. More high-quality research is needed to provide high-quality evidence for efficacy and safety.