The Hepato‐Cystic Quadrangle of Ozobia
Authors: Ozobia Nathan I 
Published: June 2021

1: PREAMBLEFor decades, the incidence of biliary tract injuries has not changed significantly since the first cholecystectomy was performed by Karl Langenbuch in 1882While each cholecystectomy is unique in its simplicity or complexity, knowledge of the Triangle of Calot, the Critical View of Safety as advocated by Strasberg and Brunt, the Hepato‐Cystic Quadrangle of Ozobia will help in further reducing the incidence of biliary tract injuries to near 0% [zero]The missing link, I believe, is in the knowledge of the Hepato‐Cystic Quadrangle and its contents.The quadrangle is divided into four quadrants [“quadlets”] and knowing the contents of each quadlet will guide the surgeon as to how aggressively to interrogate each quadlet.Clearly, the quadlets with the vital parts of the Hepato‐Biliary Complex will be avoided or interrogated with greater caution.The quadlets and their contents will be described later in this abstract2: WHAT IS THE HEPATO‐CYSTIC QUADRANGLE?This never before described anatomic oddity is a quadrangular or rectangular space under the right lobe of the liver spanning the space between the gallbladder and the hepato‐duodenal ligament with the gallbladder in the surgical position appropriately retracted with suitably placed traction forces.The quadrangle can be further subdivided into quadlets by bisecting the quadrangle vertically and horizontally.THE Q1 QUADLET HOUSES THE TRIANGLE OF CALOT AND THE CRITICAL VIEW OF SAFETY3: WHAT IS THE IMPORTANCE OF THE HEPATO‐CYSTIC QUADRANGLE?Knowledge of the quadrangle and strict adherence to dissection in Q1 and when necessary, the lower border of Q2 will greatly reduce the incidence of biliary tract injuries to near zero% Sometimes, however, in acute cholecystitis, one finds that dissection has ventured into Q3 and Q4 territories but knowledge of the contents of these quadlets will compel the surgeon to undertake other surgical techniques to complete the cholecystectomy thus avoiding injury to the underlying major structures.The hepato‐biliary gallbladder complex is replete with anomalies but I believe that knowledge of the contents of these quadlets will help one identify and deal with any aberrations.4: WHAT ARE THE BOUNDARIES OF THE HEPATO‐CYSTIC QUADRANGLE?SUPERIORLY: The undersurface of the right lobe of the liverINFERIORLY: An imaginary line from the neck of the gallbladder to the hepato‐duodenal ligamentMEDIALLY: The entire dimension of the hepato‐duodenal ligamentLATERALLY: From the neck of the gallbladder to the undersurface of the right lobe of the liver5: WHAT ARE THE CONTENTS OF THE HEPATO‐CYSTIC QUADRANGLE?Q1: CYSTIC ARTERY AND VEIN; CYSTIC LYMPH NODE OF LUND; LYMPHATICS, THE CRITICAL VIEW OF SAFETYQ2: RIGHT HEPATIC DUCT; RIGHT HEPATIC ARTERY; MEDIAL END OF THE CYSTIC ARTERY; RIGHT PORTAL VEIN MUCH DEEPERQ3: PORTA HEPATIS; CONFLUENCE OF THE RIGHT AND LEFT HEPATIC DUCTS; PROPER HEPATIC ARTERY; DIVISION OF THE PORTAL VEINQ4: COMMON HEPATIC DUCT AND DISTALLY THE COMMON BILE DUCT WITH THE TERMINATION OF OF THE CYSTIC DUCTCONCLUSIONEven for the most experienced general surgeons, cholecystectomy, laparoscopic or open remains one of the most challenging and difficult operation to performHowever, knowledge and respect of the Triangle of Calot, the Critical View of Safety and the Hepato‐Cystic Quadrangle will go a long way in helping to reduce the incidence of biliary tract injuries to near zero%Support or Funding InformationNoneThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.