Intradiscal Methylene Blue Injection for Discogenic Low Back Pain: A Meta-Analysis.

OBJECTIVES: The purpose of this study was to assess the effects of intradiscal methylene blue (MB) injection on discogenic low back pain (DLBP).

METHODS: We conducted an electronic search of the PubMed, Ovid, Ovid MEDLINE and Embase databases using the search terms "low back pain" and "methylene blue"; the search was limited to English language articles from database inception to October 2017. In addition, the reference lists of all included studies were manually searched. Two reviewers independently assessed the quality of the studies, extracted data from the included studies, and analyzed the data.

RESULTS: Five studies were included. The results of the meta-analysis indicated that the effects of intradiscal MB injection between preoperation and postoperation on DLBP were statistically significant based on the 3-month visual analog scale (VAS) or numeric rating scale (NRS) (weighted mean difference [WMD] = 3.61; 95% confidence interval [CI]: 2.46 to 4.76; P < 0.05) and Oswestry Disability Index (ODI) (WMD = 24.64, 95% CI: 12.07 to 37.21, P < 0.05), the 6-month VAS or NRS (WMD = 2.95; 95% CI: 1.20 to 4.71; P < 0.05) and ODI (WMD = 23.21, 95% CI: 12.89 to 33.53, P < 0.05), and the 12-month VAS or NRS (WMD = 3.19; 95% CI: 0.99 to 5.40; P < 0.05) and ODI (standard mean difference = 29.51, 95% CI: 20.60 to 38.42, P < 0.05).

CONCLUSIONS: Intradiscal MB injection can reduce pain severity and improve the ODI score in individuals with discogenic low back pain. Although intradiscal MB injection seems to be a safe and effective treatment for discogenic low back pain, the clinical benefits for patients with discogenic low back pain need to be further appraised in larger samples and more in-depth studies.