Importance of some technical aspects of the procedure of percutaneous posterior tibial nerve stimulation in patients with fecal incontinence

Introduction: The results of percutaneous posterior tibial nerve stimulation (PTNS) in the treatment of fecal incontinence (IF) are modest. The aim of the study is to assess the relationship of some technical aspects with the clinical response: location of the nerve, distal response (motor or sensory) and accommodation.

Methods: Prospective study of patients with FI undergoing PTNS therapy. The clinical response was assessed using the Wexner scale, defecation diary and anorectal manometry.

Results: 32 patients were studied. The intensity of localization (proximity to the nerve) was not correlated with clinical or manometric changes. Motor response was associated with a decrease on the Wexner scale [12.12 (±5.39) to 7.71 (±4.57) P < .005], the number of episodes of passive incontinence [8.78 (±9.64) to 4.11 (±7.11) P = .025], the total number of incontinence episodes [16.11 (±16.03) to 7.78 (±11.34) P = .009] and the number of days with fecal soiling [6.89 (±5.53) to 2.56 (±4.13) P = .002] and with an increase in the length of the manometric anal canal at rest [4.55 (±0.596) to 4.95 (±0.213) P = .004]. The increase in stimulation (accommodation) was inversely correlated with the decrease in the Wexner scale (r = -0.677 P < .005) and the number of days with soiling (r = -0.650 P = .022).

Conclusions: The motor response during PTNS seems to be related to a better clinical response. The accommodation phenomenon could be associated with worse results. The proximity of the electrode to the nerve does not seem to be important as long as a good distal response is achieved.