title: Development of an implantable artificial anal sphincter using a shape memory alloy.
abstract: OBJECTIVE
  The authors created a new artificial anal sphincter using a shape memory alloy (AS-SMA) to treat fecal incontinence and evaluated its validity.
  
  
  METHODS
  AS-SMA consists of 2 Ti-Ni plates to sandwich the intestine and generates a pressure of 55 mm Hg at its resting position. With the electric power supply, the 2 metals bend to form an almondlike shape making a maximum gap of 33 mm between each other at the temperature of 55 degrees C. The device was attached to the colostomy in a piglet and was operated several times a day for 1 month. Fecal continence, bowel movements, and general condition of the piglet were recorded. After the experiment, tissue damage around the device was investigated.
  
  
  RESULTS
  Fecal continence was obtained while the device was in the resting position. When it was operated, bowel movements were observed. The bowel movements to operations ratio was 82:105 (78%). During the experiment, the animal had neither abdominal distension nor vomiting. At the autopsy, there was mild inflammation and shallow burns around the device. No compression injury was detected.
  
  
  CONCLUSIONS
  AS-SMA achieved fecal continence of the colostomy. With reduction of the associated side effects, it would be a potential substitute for an impaired anal sphincter.
authors.affiliation: Department of Pediatric Surgery, Graduate School of Medicine, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Nishi
authors.forename: Takamichi
authors.initials: T
authors.lastname: Kamiyama
authors.forename: Motoshi
authors.initials: M
authors.lastname: Wada
authors.forename: Shintaro
authors.initials: S
authors.lastname: Amae
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ishii
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takagi
authors.forename: Yun
authors.initials: Y
authors.lastname: Luo
authors.forename: Takeshi
authors.initials: T
authors.lastname: Okuyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yambe
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Ryoji
authors.initials: R
authors.lastname: Ohi
mesh_terms: D000497:Alloys; D001003:Anal Canal; D000818:Animals; D001187:Artificial Organs; D003125:Colostomy; D004195:Disease Models, Animal; D005242:Fecal Incontinence / Q000628:therapy*; D020007:Implants, Experimental; D011474:Prosthesis Design; D013552:Swine
chemical_list: D000497:Alloys