New selective endoscopic sacral nerve root stimulation--an advance in the treatment of fecal incontinence

Fecal incontinence (FI) is a major part of illness and physical discomfort in the general population. Since the 1990s, sacral nerve stimulation has been well established in the treatment of neurogenic FI. The precise placement of the electrode is crucial for the success of the procedure. Eighty percent of the patients benefit from permanent treatment, but in 10-20% of the patients tested electrode placement proves impossible due to anatomical variations of the sacral foramina. In this study, we describe the technical requirements and a new method of electrode placement with reference to the anatomical (bone) landmarks in an animal model.

With a small endoscope (Verres needle), we accessed the perirectal space to identify the nervous structures. A stimulated sphincter EMG was obtained for the experimental animals and muscle action potential (MAP/M-wave), latency time [ms], and the amplitude of the motor response [μV] were recorded. Electrodes were placed, the animals killed and dissected leaving the pelvic cavity untouched. The specimens were examined in a magnetic resonance scanner and in a multi-slice computed tomography scanner to detect the electrode material and possible surgical complications. After that the specimens were dissected.

In all eight cases in the four animals tested, we were able to stimulate the sacral nerve as demonstrated by the EMG findings. No major surgical complications were observed for the procedure.

Endoscopic sacral nerve root stimulation is a safe and effective method for delivering stimulation material in the pelvis of the sheep. It is a promising procedure to be tested in humans.