Supplementary Material for: Effectiveness of low frequency electrical stimulation for radical hysterectomy women: systematic review and meta-analysis

Objectives: To explore the effects of low frequency electrical stimulation (LFES) in preventing urinary retention (UR) after radical hysterectomy (RH) in women with cervical cancer. Design: All randomized controlled trials (RCTs) of women treated with LFES for UR after hysterectomy will be included for meta-analysis. Participants/Materials, Setting, Methods: Seven electronic bibliographic databases were searched from inception to December 25, 2021. The mean difference (MD) or risk ratio (RR) with its corresponding 95% CI were selected as effect size. The meta-analysis of all data was conducted using RevMan 5.4 and the evidence was summarized according to GRADE (the grading of recommendation, assessment, development and evaluation). Results: Twelve RCTs consisting of 1033 women with cervical cancer who had undergone radical hysterectomy were included. Compared with women in the control group, women receiving LFES had improved therapeutic effect (RR=0.22,95%CI 0.16 to 0.29), and reduced residual urine volume (MD = -32.27, 95%CI -34.10 to -30.43) and catheter retention time (MD =-4.46, 95%CI -5.17 to -3.76) following treatment. Muscle strength scores of pelvic floor type I and type II muscle fibers in the LFES group were also higher than in the control group (MD =1.07, 95%CI 0.91 to 1.24). Limitations: First, because of the different ages and cancer stages of the participants, it was not appropriate to perform subgroup analyses to determine whether all participants were similarly affected by LFES treatment. Second, this review only included English and Chinese language studies, which may increase the risk of publication bias. Conclusion: LFES may be an effective auxiliary treatment for women with cervical cancer after hysterectomy, which can help reduce the duration of indwelling urethral catheter and residual urine volume.