Bilateral Posterior Tibial Nerve Stimulation in the Treatment of Rectal Evacuation Disorder: A Preliminary Report.

BACKGROUND: Posterior tibial nerve stimulation influences both motor and sensory pathways, as well as the central nervous system. Stimulation of posterior tibial nerve roots (L4 to S3) could improve stool evacuation through S3 and/or S2 stimulation.

OBJECTIVE: This study aimed to assess the efficiency of bilateral posterior tibial nerve stimulation in the treatment of rectal evacuation disorder without anatomic obstruction.

DESIGN: This was a prospective case series studying the treatment of patients with obstructed defecation by posterior tibial nerve stimulation.

SETTING: The study was conducted at a tertiary referral academic medical center.

PATIENTS: Patients with rectal evacuation disorder without anatomic obstruction who were failing maximal conservative treatments were included.

INTERVENTION: Thirty minutes of bilateral transcutaneous posterior tibial nerve stimulation was applied 3 times weekly for each patient for 6 consecutive weeks.

MAIN OUTCOME MEASURES: The primary end point was the change in the modified obstructed defecation score. Secondary end points were changes in rectal sensitivity volumes (urge to defecate volume and maximal tolerable volume) and quality of life using the Patient Assessment of Constipation-Quality of Life questionnaire.

RESULTS: Thirty-six patients (25 women) completed the trial. The mean age of patients was 57.2 years (SD = 14.4 y). No adverse events were reported. Symptomatic successful outcome was reported in 17 patients (47%) and modified obstructed defecation score decreased over 6 weeks (mean decrease = 10 points (95% CI, 8.7-11.3 points); p < 0.0001). Patients with successful outcome (responders) had relatively lower preoperative modified obstructed defecation score compared with patients with unsuccessful outcome (nonresponders). In the successful group, there were significant improvement after 6 weeks in both Patient Assessment of Constipation-Quality of Life score (mean improvement = 43.0 points (95% CI, 35.2-50.7 points); p < 0.0001) and rectal sensitivity (significant reductions in urge to defecate volume (from 258.1 ± 21.2 to 239.6 ± 15.3; p < 0.0001) and maximal tolerable volume (from 304.5 ± 24.8 to 286.8 ± 19.7; p < 0.0001)). No significant change in Patient Assessment of Constipation-Quality of Life or rectal sensitivity was observed in the nonresponders.

LIMITATIONS: The study was designed just to proof the concept, but small sample size is a limitation. Another limitation is the short duration of study of only 6 weeks.

CONCLUSIONS: Current data showed that bilateral transcutaneous posterior tibial nerve stimulation can improve symptoms in a considerable percentage of patients with obstructed defecation without anatomic obstruction. The procedure is more effective in patients with a less-modified obstructed defecation score. Additional studies are needed to discover the predictive factors for success.