Level 1: Likely reliable evidence

Fecal incontinence is a common problem for which patients may be reluctant to seek treatment, and there has been little evidence to support any medical or surgical interventions. Local injections to narrow the anal canal have been investigated but have shown little efficacy to date (Cochrane Database Syst Rev. 2010;5:CD007959).

However, a new randomized trial appears to show promise for this approach (Lancet. 2011;377:997-1003). Patients (mean age 61 years) with fecal incontinence for one year or more (at least four episodes per two-week period) were randomized to trans­anal submucosal injections of a dextranomer gel (NASHA/Dx) in stabilized hyaluronic acid vs. sham injection and were followed for six months. All patients were offered repeat treatment at one month if their symptoms had not improved and they were not experiencing persistent adverse effects. The primary outcome was treatment response, defined as ≥50% reduction in incontinence episodes.

At six months, the dextranomer gel group had a significantly higher rate of treatment response (52% vs. 31%, P=0.0089; NNT=5). The mean increase in incontinence-free days per two-week period was 3.1 days for the gel group vs. 1.7 days for the sham group (P=0.0156), and the gel was associated with a trend toward greater reduction in number of incontinence episodes per two-week period (median reduction of 6 vs. 3, P=0.09).

Adverse event rates (including proctalgia, rectal hemorrhage and diarrhea) were higher in the gel group. There were no significant differences between groups in quality-of-life measures. After an additional six months of unblinded follow-up, 69.1% of the gel users were found to have at least a 25% reduction in incontinence episodes from baseline.