title: "Triangle of safety": anatomic considerations in transvaginal natural orifice surgery.
abstract: BACKGROUND
  The introduction of transvaginal (TV) natural orifice transluminal endoscopic surgery (NOTES) brings the loss of traditionally used cutaneous landmarks for safe peritoneal access. This video describes the use of landmarks within the posterior vaginal fornix to define a "triangle of safety" wherein the peritoneal cavity can be accessed while minimizing the risk of injury to surrounding structures.
  
  
  METHODS
  The triangle of safety is best identified in the following way. The cervix and posterior fornix are visualized. Then an imaginary clock located at the base of the cervix is envisioned. The superior two corners of the triangle are represented by the 4 and 8 o'clock positions on this imaginary clock. Sometimes the cervix needs to be grasped and elevated anteriorly so that the inferior apex of the triangle delineated by the center of the rectovaginal fold is better visualized.
  
  
  RESULTS
  During hybrid TV NOTES, the rectovaginal pouch of Douglas is visualized from the umbilicus, and the vaginal port can then be safely passed through the center of the triangle. It is important that the vaginal port should be angled upward, aiming toward the umbilicus to avoid injury to the rectum. During pure TV NOTES, the incision is made with electrocautery from the 5 o'clock position to the 7 o'clock position within the triangle. The peritoneum is sharply entered, and the colpotomy is dilated with the surgeons' fingers.
  
  
  CONCLUSIONS
  The triangle of safety defines a set of landmarks between the base of the cervix and the rectovaginal fold. It allows for a safe TV access for hybrid and pure TV NOTES while minimizing the risk of injury to surrounding structures.
authors: Section of Surgical Gastroenterology, Department of Surgery, Yale University School of Medicine, 40 Temple Street, Suite 7B, New Haven, CT 06510, USA. kurt.roberts@yale.edu
authors: Kurt
authors: K
authors: Roberts
authors: Daniel
authors: D
authors: Solomon
authors: Robert
authors: R
authors: Bell
authors: Andrew
authors: A
authors: Duffy
mesh_terms: D020884:Colpotomy / Q000379:methods*; D005260:Female; D006801:Humans; D057605:Natural Orifice Endoscopic Surgery / Q000379:methods*; D015203:Reproducibility of Results; D014621:Vagina / Q000033:anatomy & histology*
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