Development of an implantable artificial anal sphincter by the use of the shape memory alloy

After the surgery after the rectal cancer, almost patients must have the stoma. It was not so desirable for some patients and loss of quality of life (QOL). In order to improve the situation, we developed an implantable artificial anal sphincter by the use of the shape memory alloy (SMA). By the use of the SMA, we can control an Evacuation. By the use of an animal experiments with the adult goats weighing 60-70 kg, which was the average weigh of the Japanese, an artificial anal sphincter with SMA was evaluated. Average internal pressure of the rectum and colon were thought to be almost 50 mmHg or so, which was evaluated in the clinical measurement. So, artificial feces with 50 mmHg pressure was tested in the animal experiment. As the results, satisfactory basic performance was recognized in the experiments. We have been developing the transcutaneous energy transmission system (TETS) for an implantable artificial heart. If we combined an implantable artificial sphincter and TETS, totally implantable artificial anal sphincter will be embodied. This system is now under developing. Following evaluation aiming at clinical application may be continued in future.