Functional evaluation of an artificial anal sphincter using shape memory alloys

Yun Luo, Toshiyuki Takagi, Takeshi Okuyama, Shintaro Amae, Motoshi Wada, Kotaro Nishi, Takamichi Kamiyama, Tomoyuki Yambe, Hidetoshi Matsuki

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.

Original languageEnglish
Pages (from-to)338-343
Number of pages6
JournalASAIO Journal
Issue number4
Publication statusPublished - 2004

ASJC Scopus subject areas

  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biomedical Engineering


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