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Efficacy and safety of methylene blue for postoperative pain of haemorrhoids: a systematic review and meta-analysis

Zhu YJ, Shi YT, Shi SY, Xu L

Annals of medicine, 2025

598 participants · 3 citations

Abstract

Objectives: Pain is a common complication after haemorrhoid surgery. In addition to anaesthetic methods, surgical techniques and postoperative interventions, surgeons also use intraoperative adjuncts to alleviate postoperative pain. This study aims to evaluate the effectiveness and safety of methylene blue in reducing postoperative pain in haemorrhoid patients.

Methods: A search was conducted in PubMed, Embase, Cochrane Library and Web of Science for randomized controlled trials (RCTs) up until 9 December 2024, involving methylene blue use for pain relief after haemorrhoid surgery. Two reviewers independently assessed the study eligibility, extracted data and evaluated the risk of bias. Data analysis was performed using Stata 18 software. The primary outcome was the visual analogue scale (VAS) pain scores at different time points within 14 days postoperatively. Secondary outcomes included the number of patients requiring analgesics and the occurrence of complications.

Results: 358 articles were retrieved and six studies involving 598 patients were included after screening. Compared with the control group, the use of methylene blue reduced pain within 12 h postoperatively(WMD -1.582, 95% CI -2.834 to -0.330, p = .013), as well as on day 2 (WMD -1.441, 95% CI - 1.874 to -1.008, p p p = .028) and day 7 (WMD -0.679, 95% CI -1.257 to -0.101, p = .021), decreased the number of patients using analgesics(RR 0.293, 95% CI 0.203 to 0.422, p p = .111) such as urinary retention,…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 598 participants or records.

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