title: A comparison of the relative risk of vessel injury with conical versus pyramidal laparoscopic trocars in a rabbit model.
abstract: OBJECTIVE
  Our purpose was to compare the relative risk of vessel injury after use of a 5 mm conical-tipped trocar, a 5 mm pyramidal-tipped trocar, and a 10 mm pyramidal-tipped trocar in a rabbit vessel model.
  
  
  METHODS
  Plastic templates were placed in front of and behind 108 mesenteric vessels in 11 anesthetized New Zealand White rabbits. Laparoscopic trocars were inserted through the templates and mesentery. The incidence of vessel injury was determined at distances from the vessels ranging from 0 to 5 mm.
  
  
  RESULTS
  The 5 mm conical trocar resulted in a vessel injury rate of 88% at 0 mm from the vessel but 0% at 1 or 2 mm. The 5 mm pyramidal trocar resulted in 100%, 88%, and 62% injury rates of 0, 1, and 2 mm from the vessels, respectively. The 10 mm pyramidal trocar resulted in a 100% injury rate at 0, 1, 2, or 3 mm from the vessels and 80% and 40% at 4 mm and 5mm, respectively.
  
  
  CONCLUSIONS
  The relative risk of vessel injury is significantly increased by the use of pyramidal-tipped trocars when compared with conical-tipped trocars, especially if larger diameter trocars are used.
authors.affiliation: Department of Obstetrics and Gynecology, University of Michigan Medical Center, USA.
authors.forename: W W
authors.initials: WW
authors.lastname: Hurd
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: M T
authors.initials: MT
authors.lastname: Schemmel
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000293:injuries*; D004195:Disease Models, Animal; D020706:Laparoscopes; D011817:Rabbits; D012307:Risk Factors; D013525:Surgical Instruments / Q000009:adverse effects* / Q000145:classification