Zusanli (ST36) acupoint injection for preventing postoperative ileus: A systematic review and meta-analysis of randomized clinical trials

• 30 RCTs with 2967 participants were involved to evaluate the preventive effect of ST36 acupoint injections with various agents for POI.
• ST36 acupoint injection demonstrated a shortened time to first flatus, bowel sounds recovery and first defecation compared to usual care alone.
• Neostigmine, vitamin B1 and metoclopramide are the commonly used agents for ST36 acupoint injection.

SummaryObjectiveTo evaluate the preventive effect of Zusanli (ST36) acupoint injections with various agents, for postoperative ileus (POI).MethodsWe searched electronic databases for randomized controlled trials from inception to 1st February 2015 evaluating ST36 acupoint injection for preventing POI. Revman 5.2.0 was used for data analysis with effect estimates presented as mean difference (MD) with 95% confidence interval (CI). Statistical heterogeneity was tested using I2 (defined as significant if I2 > 75%). We used a random effects model (REM) for pooling data with significant heterogeneity.ResultsThirty trials involving 2967 participants were included. All trials were assessed as high risk of bias (poor methodological quality). For time to first flatus, meta-analysis favored ST36 acupoint injection of neostigmine (MD −20.70 h, 95% CI −25.53 to −15.87, 15 trials, I2 = 98%, REM), vitamin B1 (MD −11.22 h, 95% CI −17.01 to −5.43, 5 trials, I2 = 98%, REM), and metoclopramide (MD −15.65 h, 95% CI −24.77 to −6.53, 3 trials, I2 = 94%, REM) compared to usual care alone. Meta-analysis of vitamin B1 favored ST36 acupoint injection compared to intra-muscular injection (MD −17.21 h, 95% CI −21.05 to −13.36, 4 trials, I2 = 89%, REM). Similarly, for time to bowel sounds recovery and first defecation, ST36 acupoint injection also showed positive effects.ConclusionsST36 acupoint injections with various agents may have a preventive effect for POI. Safety is inconclusive as few of included trials reported adverse events. Due to the poor methodological quality and likely publication bias further robust clinical trials are required to arrive at a definitive conclusion.