Placement of probes in electrostimulation and biofeedback training in pelvic floor dysfunction

Background. We examined the positioning of five commonly used probes in electrostimulation and biofeedback training. Materials and methods. Ultrasound and MRI were used to evaluate the position of these probes in two multiparous women, in reference to pelvic floor anatomy. Results. From caudal to cranial we identified the anal external sphincter, puborectal muscle, and levator group. Positioning of probes varied considerably: the recording plates are situated from 1 cm caudal to 6 cm cranial of the puborectal muscle. Most probes stretched, due to a relatively large diameter, the vagina wall, anal external sphincter, or puborectal muscle beyond physiological proportions. On straining, all probes were pushed upwards into the rectum. Conclusion. The positioning of all examined probes varied considerably. Hence it is not likely that these probes give a reliable and uniform registration of muscular activity of the pelvic floor function or are all optimal for electrostimulation.