title: Development of an animal model to investigate optimal laparoscopic trocar site fascial closure.
abstract: BACKGROUND
  The rate of hernia formation after closure of 10-12 mm laparoscopic trocar sites is grossly under-reported. Using an animal model, we have developed a method to assess trocar site fascial dehiscence and the strength of different methods of fascial closure.
  
  
  METHODS
  Pigs (n = 9; 17 ± 2.5 lbs) underwent placement of 12 mm Hasson trocars with pneumoperitoneum maintained for 1 h. Three closure techniques (Figure-of-eight; simple interrupted; pulley) were compared with no fascial closure and to native fascia at five randomly allocated abdominal wall midline locations. Necropsy was performed on the fourth postoperative d. Statistical comparisons of tensile strength and breaking strength based on closure type and trocar location were made using ANOVA with Tukey's tests.
  
  
  RESULTS
  The mean (SD) force (Newtons) required for fascial disruption varied significantly with closure type [Native Fascia 170 (39), Figure-of-eight 169 (31), Pulley 167 (59), Simple Interrupted 151 (27), No Closure 108 (28)]; P = 0.007. The mean force required for fascial disruption was significantly increased for Native Fascia, Figure-of-eight, and Pulley relative to No Closure (P = 0.013, P = 0.015, P = 0.023, respectively). The mean (SD) force (in Newtons) required for fascial disruption also varied significantly with location of trocar [subxiphoid 181 (43), supraumbilical 151 (23), Umbilical 146 (23), infraumbilical 168 (62), suprapubic 120 (38)]; P = 0.03. The mean force for subxiphoid location was significantly increased relative to the suprapubic location (P = 0.021).
  
  
  CONCLUSIONS
  We have developed a novel assessment model that reliably detects differences in fascial integrity after laparoscopic trocar placement and closure. This model will allow for further testing of various trocars and closure techniques, and facilitate hernia prevention strategies.
authors.affiliation: Department of Surgery, University of Texas Health Science Center San Antonio (UTHSCSA), San Antonio, Texas 78229, USA.
authors.forename: Kent R
authors.initials: KR
authors.lastname: Van Sickle
authors.forename: Hanuma Reddy
authors.initials: HR
authors.lastname: Nanda Kumar
authors.forename: Amit
authors.initials: A
authors.lastname: Parikh
authors.forename: Arturo A
authors.initials: AA
authors.lastname: Ayon
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Cohn
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005205:Fascia / Q000502:physiology; D000071938:Fasciotomy; D006555:Hernia, Ventral / Q000503:physiopathology / Q000517:prevention & control*; D010535:Laparoscopy / Q000009:adverse effects* / Q000295:instrumentation; D011028:Pneumoperitoneum, Artificial; D013314:Stress, Mechanical; D013525:Surgical Instruments; D013529:Surgical Wound Dehiscence / Q000503:physiopathology / Q000517:prevention & control*; D034421:Sus scrofa; D013536:Suture Techniques
keywords: Fascial closure; Hernia; Tensiometer; Trocar