Transanal irrigation for low anterior resection syndrome: a systematic review and narrative synthesis with emphasis...

Low anterior resection syndrome (LARS) affects up to 80% of patients following sphincter-preserving rectal surgery, profoundly impacting quality of life. Transanal irrigation (TAI) has emerged as a promising therapeutic intervention; however, the current evidence remains heterogeneous regarding its effectiveness, adherence, and optimal delivery methods. The specific contribution of nursing support in TAI implementation has not yet been systematically evaluated.

We conducted a systematic review in accordance with the PRISMA 2020 statement across five electronic databases (PubMed, Embase, CINAHL, Cochrane Library, and Scopus) covering January 2012 to October 28^th, 2025. The protocol was registered on the Open Science Framework (OSF registration: https://osf.io/nzsm6; DOI: 10.17605/OSF.IO/NZSM6; registration date: September 8^th, 2025) and reflected pre-specified methodology established prior to study selection. Eligible studies included adult patients (≥18 years) diagnosed with LARS who received TAI as the primary intervention. The Joanna Briggs Institute Critical Appraisal Tools were used to assess methodological quality and risk of bias. Certainty of evidence was evaluated using the GRADE framework.

Four studies met the inclusion criteria (two randomized controlled trials, one prospective observational study, one mixed-methods study), comprising 332 patients treated with TAI. Across studies, TAI consistently reduced LARS scores by 8.5-23 points (mean difference range across studies), with 68-82% of individual patients achieving clinically meaningful improvement (≥4 points MCID). No serious adverse events were reported; minor adverse events (mild cramping, transient discomfort) occurred in 1.2% of patients (3/242) and resolved without treatment discontinuation. Studies that integrated structured nurse-led education and follow-up (two studies, 68 patients) achieved adherence rates of 85-100%, compared with 60-78% in studies with minimal-to-moderate nursing involvement (two studies, 88 patients). No formal meta-analysis was performed due to heterogeneity in adherence definitions and measurement timepoints. Instead, a structured narrative synthesis following the Synthesis Without Meta-analysis (SWiM) guidelines was conducted. Overall certainty of evidence ranged from very low for quality-of-life outcomes to moderate for prevention of serious adverse events (GRADE assessment).

TAI shows promise an effective and well-tolerated intervention for LARS, particularly when delivered through structured, nurse-supported protocols. However, the limited number and heterogeneity of available studies, combined with small sample sizes (total N=332) and short follow-up durations (median 4 months), highlight the need for large, multicenter randomized trials with extended follow-up (≥12 months) to confirm long-term effectiveness and establish standardized implementation strategies.