Preoperative anorectal manometry as a predictor of function after ileal pouch anal anastomosis: a systematic review and meta-analysis.

Background: Since the ileal pouch anal anastomosis (IPAA) was first described, anorectal manometry (ARM) has been used to study its physiology and function. Few studies have investigated if preoperative ARM can predict pouch function.

Methods: Pubmed, EMBASE, and the Cochrane Library databases were systematically searched. Papers detailing preoperative ARM results and postoperative functional outcomes of patients with IPAA were included. Meta-analysis with meta-regression was performed, assessing the relationship between preoperative manometric results and objective postoperative functional outcomes including frequency, seepage, pad usage and medications, and functional scoring systems including Wexner Incontinence and Oresland Scores.

Results: Results from 31 studies were analysed. Mean resting pressure (MRP) decreased significantly (- 23.16 mmHg, 95% CI - 27.98 to - 18.35, p < 0.01) after pouch formation but before ileostomy reversal, with subsequent minor increase (3.51 mmHg, 95% CI 0.93 to 6.09, p = 0.01) by 6 months after reversal of ileostomy. Pooled bowel frequency was 5.4 per 24 h (4.90-5.91), day and night-time soiling, incontinence, and pad usage rates were 16% (9-24%), 26% (19-33%), 12% (4-20%), and 21% (13-30%) respectively. Pooled Oresland and Wexner Scores were 3.81 (2.92-4.70) and 3.45 (2.71-4.19). A significant association between preoperative MRP and Wexner Score was observed (p < 0.001). As a result of risk of bias, study heterogeneity, and variation in manometry systems, certainty of evidence was low or very low.

Conclusion: Preoperative predictors of function inform patient and clinician decision-making. Further investigations into the association between preoperative MRP and Wexner Score using modern ARM techniques are warranted.