Anal incontinence improvement after silicone injection may be related to restoration of sphincter asymmetry.

Background: This study aimed to evaluate manometric parameters that may explain improvement in anal incontinence using a silicone bulking agent.

Methods: Incontinent patients having internal sphincter defects were prospectively selected and injected with a silicone bulking agent. Manometry and endoanal ultrasound were performed before and 3 months after injections.