Can Targeting Sphincter Spasm Reduce Post-Haemorrhoidectomy Pain? A Systematic Review and Meta-Analysis

Background Haemorrhoidectomy is often complicated by significant post-operative pain, to which spasm of the internal anal sphincter is thought to be a contributing factor. This study appraises the evidence behind interventions aimed at lowering sphincter spasm to relieve post-haemorrhoidectomy pain. Methods A Preferred Reporting Items for Systematic Reviews and Meta-analyses compliant systematic review was conducted. Medline, EMBASE, and CENTRAL databases were systematically searched. All RCTs which compared interventions targeting the internal anal sphincter to relieve pain post excisional haemorrhoidectomy were included. The primary outcome measure was pain on the visual analogue scale. Results Of the initial 10,221 search results, 39 articles were included in a qualitative synthesis, and 33 studies were included in a meta-analysis. Topical glyceryl trinitrate (GTN) reduced pain on day 7 (7 studies, 485 participants), with a mean difference and 95% confidence interval (MD, 95% CI) of -1.34 (-2.31; -0.37), I-2 = 91%. Diltiazem reduced pain on day 3 on the VAS, and the MD was -2.75 (-398; -1.51) shown in five studies (n = 227). Botulinum toxin reduced pain on day 7, in four studies with 178 participants, MD -1.43 (-2.50; -0.35) I-2 = 62%. The addition of Lateral Internal Sphincterotomy to haemorrhoidectomy reduced pain on day 2 in three studies with 275 participants, MD of -2.13 (-3.49; -0.77) I-2 = 92%. The results were limited by high heterogeneity and risk of bias. Conclusion Evidence suggests that lateral sphincterotomy, administration of botulinum toxin and the application of topical diltiazem or GTN can reduce post-operative pain after haemorrhoidectomy. Lateral sphincterotomy should not be routinely used due to the risk of incontinence.