Literature Review and Meta-Analysis of Transcutaneous Electrical Nerve Stimulation in Treating Chronic Back Pain.

BACKGROUND AND OBJECTIVES: This study is a meta-analysis of randomized controlled trials comparing the efficacy of transcutaneous electrical nerve stimulation (TENS) to a control and to other nerve stimulation therapies (NSTs) for the treatment of chronic back pain. METHODS: Citations were identified in MEDLINE, the Cochrane Library, Google Scholar, and ClinicalTrials.gov through June 2014 using the following keywords: nerve stimulation therapy, transcutaneous electrical nerve stimulation, back pain, chronic pain. Control treatments included sham, placebo, or medication only. Other NSTs included electroacupuncture, percutaneous electrical nerve stimulation, and percutaneous neuromodulation therapy. RESULTS: Twelve randomized controlled trials including 700 patients were included in the analysis. The efficacy of TENS was similar to that of control treatment for providing pain relief (standardized difference in means [SDM] = -0.20; 95% confidence interval [CI], -0.58 to 0.18; P = 0.293). Other types of NSTs were more effective than TENS in providing pain relief (SDM = 0.86; 95% CI, 0.15-1.57; P = 0.017). Transcutaneous electrical nerve stimulation was more effective than control treatment in improving functional disability only in patients with follow-up of less than 6 weeks (SDM = -1.24; 95% CI, -1.83 to -0.65; P < 0.001). There was no difference in functional disability outcomes between TENS and other NSTs. CONCLUSIONS: These results suggest that TENS does not improve symptoms of lower back pain, but may offer short-term improvement of functional disability.

In vitro Penetration and in vivo Distribution of Honokiol into the Intervertebral Disc in Rat.

Honokiol is a potential candidate for the treatment of intervertebral disc (IVD) degeneration. In this study, we develop in vitro and in vivo methods to detect the distribution of honokiol in intervertebral discs using high-performance liquid chromatography. A rat tail disc was used for both experimental models. For the in vivo animal experiment, blood samples and tail discs were collected at 15, 30, 60, 120 and 240 min after honokiol administration (30 mg/kg, i.v.). The analyte was separated by a mobile phase of methanol and 10 mM NaH2PO4 buffer at pH 2.8 (78:22, v/v) and pumped through a reversed-phase analytical column (250 × 4.6 mm, particle size 5 µm) at room temperature. The in vitro experimental results demonstrated that honokiol diffused into the intervertebral disc and was concentration-dependent. The active concentration is obtained for the therapeutic level at 15 and 30 min after honokiol administration in the in vivo model.