Resting vector volume measured before ileostomy reversal may be a predictor of major fecal incontinence in patients with mid or low rectal cancer: a longitudinal cohort study using a prospective clinical database.

ABSTRACT

PURPOSE: Despite a high incidence of fecal incontinence following sphincter-preservation surgery (SPS), there are no definitive factors measured before ileostomy reversal that predict fecal incontinence. We investigated whether vector volume anorectal manometry before ileostomy reversal predicts major fecal incontinence following SPS in patients with mid or low rectal cancer. METHODS: This longitudinal prospective cohort study comprised 173 patients who underwent vector volume anorectal manometry before ileostomy reversal. The Fecal Incontinence Severity Index was measured 1 year after the primary SPS and classified as major incontinence (FISI score ≥ 25) or continent/minor incontinence (FISI score < 25). Multivariable logistic regression analysis was used to identify predictors of major incontinence. RESULTS: Ninety-two patients (53.1%) had major incontinence. Although tumor stage, location, and neoadjuvant chemoradiotherapy were comparable, the major incontinence group had lower resting pressure (28.4 vs. 34.3 mmHg, P = 0.027), greater asymmetry at rest (39.1% vs. 34.1%, P = 0.002) and squeezing (34.2% vs. 31.4%, P = 0.046), shorter sphincter length (3.3 vs. 3.7 cm, P = 0.034), and lower resting vector volume (143,601 vs. 278,922 mmHg2 mm, P < 0.001) compared with the continent/minor incontinence group. Resting vector volume was the only independent predictor of major incontinence (odds ratio = 0.675 per 100,000 mmHg2 mm, 95% confidence interval, 0.532-0.823; P = 0.006). CONCLUSIONS: This study revealed that resting vector volume before ileostomy reversal may predict major fecal incontinence. We suggest that the physiology of the anorectum should be discussed with patients before ileostomy reversal in patients at high risk of fecal incontinence.