Microendoscopic discectomy versus microscopic discectomy for treatment of lumbar disc herniations: a systematic review of randomized controlled trials

Objective To compare the effectiveness and safety of microendoscopic discectomy (MED) versus microscopic discectomy (MD) for treatment of lumbar disc herniations. Methods Key words were defined as microendoscopic discectomy, microscopic discectomy, lumbar disc herniation, etc. The electronic databases (PubMed, EMbase, Cochrane Central Register of Controlled Trials, CNKI, and Wanfang) were searched in order to retrieve randomized controlled trials (RCTs) about comparing MED and MD for the treatment of lumbar disc herniations. We also applied manual searching to screen out relevant journals. Data were extracted and evaluated by two reviewers independently. The quality of the included trails was evaluated by Jadad scales. Cochrane collaboration's RevMan 5.0.24 were used for data analysis. Results Four RCTs involving 1069 patients were included in the Meta⁃analysis. Results of Meta⁃analysis showed that: the Oswestry dysfunctional index (ODI) after operation in MED group was not significantly different from that in the MD group (MD = ⁃ 0.170, 95%CI: ⁃ 3.590-3.260; P = 0.920); dural tears in MED group were higher than those of MD group (RR = 3.040, 95%CI: 1.170-7.890; P = 0.020); there were no significant difference between MED group and MD group in terms of root injury (RR = 5.130, 95% CI: 0.890-29.420; P = 0.070) and recurrent herniation (RR = 2.320, 95%CI: 0.970-5.520; P = 0.060); there were significant difference between MED group and MD group in terms of surgical time (MD = 10.780, 95%CI: 7.180-14.370; P = 0.000), size of incision (MD = ⁃ 0.950, 95%CI: ⁃ 1.840-0.070; P = 0.030) and length of hospital stay (MD = 0.210, 95%CI: ⁃ 0.080-0.340; P = 0.002). There was no significant difference between MED group and MD group in terms of blood loss (MD = 27.420, 95% CI: ⁃ 8.840-63.680; P = 0.140). Conclusion According to present knowledge, the two techniques were found to be effective for the treatment of lumbar disc herniations, but recurrent herniations were significantly more common in MED group. As for the safety of the two techniques, dural tears and root injuries were significantly more common in MED group. Because of the limitation of the quality and amount for the RCTs included, the results of this systematic review should be prudently cited, and more high quality RCTs are needed to be performed. DOI：10.3969/j.issn.1672⁃6731.2012.04.00