THE CLINICAL EFFECTS OF NEUROMODULATION THERAPIES IN THE TREATMENT OF FAECAL INCONTINENCE

Abstract

Background and Aims Sacral nerve stimulation (SNS) is an established therapy for faecal incontinence (FI). Percutaneous tibial nerve stimulation (PTNS) is a newer, less-invasive treatment. The effectiveness, cost and acceptability of these treatments have not been systematically compared. Methods A systematic review of neuromodulation interventions for FI and an investigator-blinded, randomised pilot trial of PTNS vs. SNS including parallel quantitative (clinical outcomes and cost) and qualitative studies. Results The systematic review determined on intention-to-treat, the median success rates for SNS were 63% (range 33-66%), 58% (range 52-81%) and 54% (range 50-58%) in the short, medium and long terms respectively. The success rate for PTNS was 59% at 12 months. In the pilot trial: 40 patients (39 female; mean age 59 years) met eligibility criteria. As designed, 23 were randomised to receive SNS and 17 PTNS. 15 patients progressed to permanent SNS implantation and 16 patients received a full course of PTNS. Within group effect sizes were marginally greater for SNS than PTNS on available case analysis. FI episodes per week at baseline, 3 months and 6 months follow-up: SNS median 5.75 (IQR 5.75-15.5 ) [mean 11.4 (SD 12.0)], 2.5 (2-4.5) [4.0 (4.0)], 1.75 (1.5-5) [4.9 (6.9)], vs. PTNS median 6.5 (IQR 2.5- 16.5) [mean 10.6 (SD 11.2)], 3.5 (0.75-7.25) [5.8 (6.9)], 2.5 (0.75-10.75) [6.3 (6.9)]. At least 50% improvement in FI episodes per week at 6 months: SNS 61% vs. PTNS 47%. Effect estimates for SNS with chronic implanted stimulation were larger (67% at 6 months). Clinical FI scores and quality of life improvements complemented these results. Qualitative analysis demonstrated a very high acceptability and safety profile for both treatments. Total costs were £2,906 (SD £122) per patient for PTNS and £12,748 (SD £4,175) for SNS. Conclusions Definitive trial data between SNS or PTNS is lacking. This RCT pilot study determined that in the short-term, SNS confers a small clinical benefit over PTNS for FI but is much more expensive.