BACKGROUND: The internal anal sphincter (IAS) is comprised of smooth muscle that tonically contracts providing a physical barrier to the passage of gas and faeces. Structural defects of the IAS resulting from obstetric, iatrogenic or accidental injury can reduce passive sphincter tone and thereby impair faecal continence. Current therapeutic strategies aimed at reducing stool frequency and fluidity fail to address the underlying defect and are generally considered unsatisfactory. This pilot study will determine the safety and efficacy of a new technique of lAS augmentation using implantable silicone.
METHODS: 10 patients with passive faecal incontinence were selected. Inclusion criteria were as follows: (1) low resting anal pressure, (2) deficient IAS on anal ultrasound and (3) failed conservative treatment. Injection of silicone (3 x 2.5ml) was performed into the intersphincteric space under local anaesthetic in the prone position. Primary endpoints were change in Wexner's incontinence score (WIS) at 3 months and complications. Secondary endpoints were patient-assessed improvement in continence, Gastrointestinal Quality of Life Index (GIQLI), maximum resting (MRP) and maximal squeeze pressures (MSP).
RESULTS: The procedure was well tolerated with no complications. Significant improvements in WIS and MRP were measured at 3 months (p<0.018 and p<0.007, Wilcoxin matched pairs test) with no change in MSP (p<0.12, Wilcoxin matched pairs test). 7/10 subjects considered treatment a success with a mean improvement in WIS of 8.9 for this group versus 0.0 in 3/10 who failed. GIQLI was significantly improved in those reporting treatment as successful (mean 130 versus 106). Therapy produced best results in subjects with a localised defect of the IAS and very poor resting pressures.
CONCLUSION: In the short-term, injectable silicone is safe and well tolerated. Silicone is effective for treatment of passive faecal incontinence resistant to conservative therapy related to internal anal sphincter disruption.
Source: Original abstract