RESUMO
BACKGROUND: The effect of posterior tibial nerve stimulation (PTNS) on the mechanisms of anal continence has not been fully demonstrated. The aim of this study was to assess the anal manometric response after percutaneous PTNS in patients with fecal incontinence (FI). METHODS: This was a prospective study in patients with FI undergoing 1 weekly session of percutaneous PTNS for 8 weeks. A clinical assessment (Wexner scale) and a complete study of up to 22 manometric parameters were carried out prior to treatment and 2-4 weeks after the end of treatment. RESULTS: A total of 32 patients were evaluated. After therapy, there was a decrease in the average Wexner score [12.6 (± 5.2) to 9.5 (± 5.2) (P < 0.005)] and an increase in the "anal canal length at rest" [4.55 (± 0.60) to 4.95 (± 0.21) P = 0.004], without observing variations in other manometric parameters. The decrease in the Wexner score was significantly correlated with an increase in the "pressure at 5 cm at rest" after therapy (r = 0.464 P = 0.030). CONCLUSIONS: In our study, PTNS was associated with a significant decrease in the Wexner score and with an increase in the functional length of the anal canal at rest. The improvement in the Wexner scale was correlated with an increase in pressure at rest in the theoretical area of the anorectal junction.