The short-term effects of posterior tibial nerve stimulation on anorectal physiology in patients with faecal incontinence: a single centre experience

Abstract

Background:Posterior tibial nerve stimulation (PTNS) is a novel treatment for patients with faecal incontinence (FI) and may be effective in selected patients; however, its mechanism of action is unknown. We sought to determine the effects of PTNS on anorectal physiological parameters.Methods:Fifty patients with FI underwent 30 min of PTNS treatment, weekly for 12 weeks. High-resolution anorectal manometry, bowel diaries and Vaizey questionnaires were performed before and after treatment. Successful treatment was determined as a greater than 50% reduction in FI episodes.Results:Fifty patients with FI were studied; 39 women, median age 62 years (range 30–82). Compared with pretreatment, there were reductions in episodes of urgency (16.0 versus 11.4, p = 0.006), overall FI (14.5 versus 9.1, p = 0.001), urge FI (5.4 versus 3.2, p = 0.016) and passive FI (9.1 versus 5.9, p = 0.008). Vaizey score was reduced (16.1 versus 14.5, p = 0.002). Rectal sensory volumes (ml) decreased (onset 40.3 versus 32.6, p = 0.014, call 75.7 versus 57.5, p < 0.001, urge 104.1 versus 87.4, p = 0.004). There was no significant change in anal canal pressures (mmHg) (maximum resting pressure 41.4 versus 44.2, p = 0.39, maximum squeeze pressure, 78.7 versus 88.2, p = 0.15, incremental squeeze pressure 37.2 versus 44.1, p = 0.22). Reduction in FI episodes did not correlate with changes in physiological parameters (p > 0.05). Treatment success of 44% was independent of changes in manometric parameters (p > 0.05).Conclusions:PTNS has a measureable physiological effect on rectal sensory volumes without an effect on anal canal pressures. It also reduces FI episodes; however, this effect is independent of changing physiology, suggesting that PTNS has a complex mechanism of action.

A novel combined anorectal biofeedback and percutaneous tibial nerve stimulation protocol for treating fecal incontinence

“…This, however, is in contrast to some previous reports in both BF and PTNS. 18 As the variables most likely to improve following BF, for example anal squeeze pressure, 19 and following PTNS, for example anal resting pressure and rectal sensory volumes, 18 were numerically improved in our study but did not reach statistical significance the likely explanation for this finding is the small patient numbers. As physiological changes were defined as a secondary endpoint in the current study, power to detect change was limited, and it is possible that including more patients would replicate previous reports of some physiological improvements.…”

“…This is similar to previous reports of the time line of improvement in PTNS. 18 Nevertheless, data regarding efficacy in this trial should be interpreted with caution, as this was a small cohort, with no sham treatment arm, in a selected group of patients. This probably explains the unusually high rates of success at the end of treatment (92%), even as assessed by the objective measure of 50% or more improvement in FI episodes.…”

Main Manometric Findings and Potential for Anorectal Physical Therapy in the Treatment of Patients With Evacuation Disorders

“…TNS, on the other hand, seems to have beneficial effects on the PR of patients with IF. In the study by Heywood et al, patients undergoing TNS showed a 6.8% increase in RP values, however without statistical significance, probably because of the small sample size and the short follow-up interval (13) .…”

Short-term clinical and manometric outcomes of percutaneous tibial nerve stimulation for faecal incontinence: a large single-centre series

“…A surface electrode is placed on the ipsilateral foot, medial to the calcaneum. Correct placement is confirmed by demonstrating either a motor response (plantar flexion of the great toe) or a sensory response (tingling to the toes, arch or heel) through incremental stimulation increases[ 9 , 13 ].…”