title: An experimental study on the utility of a 3-mm ultrasonically activated trocar system.
abstract: OBJECTIVE
  A prototype of a 3-mm ultrasonically activated trocar system supplied by Olympus Corporation was evaluated experimentally in terms of its utility and safety.
  
  
  METHODS
  Three piglets with an average weight of 12 kg were used. A pneumoperitoneum was created by Hasson's technique. Eleven punctures were made with a disposable conical 3-mm trocar (CT), 9 punctures with a 3-mm radially expanding trocar (ET), and 13 punctures with a 3-mm ultrasonically activated trocar (UT) under laparoscopic control. The authors recorded the time for abdominal penetration, the severity of the peritoneal tenting, the presence of elevated abdominal pressure of 5 mm Hg or more at the penetration, and the maximal force applied to the trocar to remove from the abdominal wall.
  
  
  RESULTS
  The average times for penetration were 11.8, 9.4, and 3.8 seconds with CT, ET, and UT, respectively (P < .05, CT v. UT, ET v. UT). The average maximal forces at the trocar removal were 10.52, 21.17, and 21.24 N with CT, ET, and UT, respectively (P < .05, CT v. ET, CT v. UT). Elevation of abdominal pressure of 5 mm Hg or more was recorded in CT and ET but not in UT. Peritoneal tenting was the most severe in ET and minimal in UT. No complication related to the UT system was found.
  
  
  CONCLUSIONS
  The 3-mm UT is a simple and safe device and is expected to become commercially available.
authors.affiliation: Department of Surgery, Miyagi Children's Hospital, Sendai 989-3126, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Nio
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ishii
authors.forename: Shintaro
authors.initials: S
authors.lastname: Amae
authors.forename: Motoshi
authors.initials: M
authors.lastname: Wada
authors.forename: Kotaro
authors.initials: K
authors.lastname: Nishi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D004867:Equipment Design; D020706:Laparoscopes; D013525:Surgical Instruments; D013552:Swine; D014465:Ultrasonics