RESUMO
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.