The efficacy of retrograde and antegrade enemas in the management of low anterior resection syndrome in patients undergoing rectal resection: a systematic review and meta-analysis.

BACKGROUND

Rectal resection could potentially cause low anterior resection syndrome (LARS). Although recent studies have reported the efficacy of enema against LARS, no systematic review and meta-analysis has been conducted.

METHODS

A systematic search was conducted in PubMed, EMBASE, MEDLINE, CINAHL Complete, Cochrane library and Web of Science. Eligible studies that quantified the effect of enema vs. other approaches on LARS following rectal resection were selected. Meta-analysis was conducted by using RevMan 5.4 software and StataMP 17. Where meta-analysis was not possible, vote counting was performed.

RESULTS

This study comprised five RCTs with 159 participants and meta-analysis was performed in 4 studies. Compared with the control group, enema reduced LARS score with mean differences of -10.84 (95% CI: -16.71 to -4.98, P = 0.0003). Subgroup analysis based on the type of enema were performed, with three European studies using retrograde enema and one Asian study using antegrade enema, with mean differences of -13.77 (95% CI: -17.97 to -9.57, P < 0.00001) and -4.86 (95% CI: -9.26 to -0.46, P = 0.03), respectively. According to follow-up period, two trials reported short-term effects and the other two investigated medium/long-term effects with mean differences of -14.22 (95% CI: -20.05 to -8.38, P = 0.23) and -7.59 (95% CI: -14.47 to -0.71, P = 0.13), respectively. One study that used antegrade enema was key contributor to the substantial interstudy heterogeneity by the leave-one-out sensitivity analysis. After exclusion of this study, no heterogeneity was found (t2 = 0.00; χ2 = 1.63, df = 2, p = 0.44; I2 = 0%). Vote counting also showed positive effects of enema on LARS.

CONCLUSIONS

Enema, particularly retrograde enema, is effective in managing LARS. However, the effectiveness of antegrade enema deserves further investigation. The short-term effects of enema are more pronounced compared to long-term outcomes. Due to the limited number of included studies, these findings should be taken cautiously. More RCTs on other continents are needed to validate the impact of enema on LARS, as well as to develop standardised protocols to facilitate clinical practice.

PROSPERO REGISTRATION: CRD42024539973.