Implantable Agents for Fecal Incontinence: An Age-Matched Retrospective Cohort Analysis of GateKeeper versus SphinKeeper.

Background. We aim to evaluate morphofunctional changes of the sphincter complex after GateKeeper (GK) and SphinKeeper (SK) procedures and correlate these with symptom improvement. Methods. Ten consecutive females undergoing SK implant were age-matched with a cohort of 10 females who previously underwent the GK procedure. Patients in the SK and GK groups underwent implantation of 10 and 6 prostheses, respectively. Muscle tension (Tm), expressed in millinewtons per centimetre squared, mN (cm2)-1, was calculated using the equation Tm = P(ri)(tm)-1, where P is the average maximum squeeze pressure and ri and tm the inner radius and thickness of the external anal sphincter, respectively. The pre- and postimplant changes in Tm and Cleveland Clinic Fecal Incontinence Score (CCFIS) were tested by linear and Poisson regression models, respectively. Results. The CCFIS significantly improved in both groups at 12-month postimplantation. Although not reaching statistical significance, symptom improvement after SK was 33% above that observed after GK (P = .088). Compared to the baseline, a significant increase in Tm was observed in both groups at 12 months (GK, 508.1 [478.8-568.0] vs 864.4 [827.0-885.8] mN (cm2)-1; SK, 528.0 [472.7-564.0] vs 858.6 [828.0-919.6] mN (cm2)-1, P = .005). Compared to the GK group, Tm was significantly higher in patients after SK implant (158.3 mN (cm2)-1 [95% confidence interval, 109.6-207.0]; P < .001), after controlling for baseline values, at 12-month postimplantation. Conclusions. GK and SK are safe and effective treatments for FI with good short-term clinical outcomes. Comparative analysis showed superiority of SK over GK in terms of gain in Tm, with borderline significantly better improvement in symptoms. Larger studies are needed to confirm these findings.