Piezoresistive Sensors for Medical Applications

Rectal manometry provide a useful method to objectively assess the physiology of defecation. We developed a probe with 10 embedded transducers for evaluating the dynamic rectal pressure profile. The innovation of the probe is to use small piezoresistive dice and reduce the packaging resulting in a very small assembly. The diameter of the probe is 9 mm with a length of 20 cm. The length could be extended up to 30 cm with 15 transducers. We performed measurement of the colorectal dynamic pressure profile in one healthy test person. We could detect pressure waves caused by the evacuation reflex at a frequency of 3 to 4 per minute with an pressure increase of 4-5 kPa. The diagnostic measurement of the dynamic rectal pressure profile may provide additional information in cases with colorectal disorders.