Transanal Irrigation in Patients with Low Anterior Resection Syndrome After Rectal-Sphincter-Preserving Surgery for Oncological and Non-Oncological Disease: A Systematic Review

Background/Objectives: Transanal irrigation (TAI) has been recognized as a safe and effective treatment for neurological bowel dysfunction, chronic constipation or fecal incontinence and has also been proposed for patients with low anterior resection syndrome (LARS). The aim of the present systematic review was to evaluate the feasibility and effectiveness of TAI in patients with significant LARS symptoms. Methods: We performed a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and guidelines in addition to the Cochrane Handbook for Systematic Reviews of Interventions. The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023436839). The risk of bias was assessed using a modified version of the Downs and Black checklist. The main outcome was improvement in low anterior resection syndrome after TAI assessed by change in LARS score. Results: After an initial screening of 3703 studies, 9 were included and underwent qualitative synthesis (among them, 3 were randomized clinical trials). All studies recorded an improvement in LARS score following TAI procedure and almost all studies showed an improvement in other bowel function outcomes (Memorial Sloan Kettering Cancer Center Bowel Function Instrument (MSKCC BFI, ), Cleveland Clinic Incontinence Score (CCIS), visual analog scale (VAS), Cleveland Clinic Florida Fecal Incontinence Score (CCFFIS), fecal incontinence score (FI score), Obstructed Defecation Syndrome (ODS) score) and quality of life (QoL) scores. The discontinuation rate ranged from 0% to 41%. The rate of adverse events was high (from 0 to 93%); moreover, no uniformity was found in the various protocols used among the different studies. Conclusions: The results of this review show that TAI is effective in the treatment of LARS, improving the LARS score, the other bowel function outcomes and the QoL scores. The absence of a treatment protocol validated by the scientific community is reflected in the high disparity in terms of adverse events and discontinuation of therapy, in addition to representing an intrinsic limitation to the study itself.