title: A new measure to assess the difficulty of liver resection.
abstract: BACKGROUND
  There is no valid measure to assess surgical difficulty and feasibility of a planned liver resection. It is the objective of this study to evaluate a mathematical measure from a 3D graphical analysis.
  
  
  METHODS
  Eleven different 3D models of hepatic tumours were evaluated by experts for resectability and analysed with Amira graphic software taking into consideration the portal and hepatic venous vascular relationships. Virtual resection volumes with increasing resection margins from 1 to 30 mm were determined separately for portal veins, hepatic veins, their intersections and volume unions. The integral of the increasing resection volumes was defined as risk coefficient. The risk coefficients from this volumetric analysis were compared with the expert opinion.
  
  
  RESULTS
  The risk coefficient based on the integral of portal venous and hepatic venous volume unions reproduced the expert opinion highly significantly (correlation coefficient 0.9, p<0.05) and more accurately than volumetric analysis of the planned resection margin.
  
  
  CONCLUSIONS
  With automated volumetric analysis, anatomically problematic situations in liver surgery can be reproduced and scaled. The risk coefficient obtained is a suitable objective measure for defining risk areas in liver surgery.
authors.affiliation: Surgical Research Unit OP 2000, Campus Berlin Buch, Charitè Universitätsmedizin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Beller
authors.forename: S
authors.initials: S
authors.lastname: Eulenstein
authors.forename: T
authors.initials: T
authors.lastname: Lange
authors.forename: M
authors.initials: M
authors.lastname: Niederstrasser
authors.forename: M
authors.initials: M
authors.lastname: Hünerbein
authors.forename: P M
authors.initials: PM
authors.lastname: Schlag
mesh_terms: D000465:Algorithms; D005103:Expert Systems; D006498:Hepatectomy / Q000295:instrumentation*; D006499:Hepatic Artery / Q000601:surgery; D006503:Hepatic Veins / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D008113:Liver Neoplasms / Q000098:blood supply / Q000601:surgery*; D012306:Risk; D012984:Software; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014584:User-Computer Interface