title: Accuracy evaluation of a mitral valve surgery assistance system based on optical tracking.
abstract: OBJECTIVE
  Mitral valve reconstruction is a widespread surgical method to repair incompetent mitral valves, which usually includes implantation of a ring prosthesis. To date, intraoperative analysis of the mitral valve is merely based on visual assessment using simple surgical tools, which might not allow for accurate assessment of the complex anatomy.
  
  
  METHODS
  We propose a novel intraoperative computer-based assistance system, which combines passive optical tracking technology with tailored measurement strategies applicable during different phases of the intraoperative workflow. Based on the assessment of the valvular apparatus by customized tracked instruments, the system (1) generates an enhanced three-dimensional visualization, which (2) incorporates accurate quantifications and (3) provides assistance, e.g., in terms of virtual prosthesis selection.
  
  
  RESULTS
  Phantom experiments in a realistic environment revealed a high system accuracy (mean precision [Formula: see text] mm and mean trueness [Formula: see text] mm) and a low user error (mean precision [Formula: see text] mm and mean trueness [Formula: see text] mm). The assistance system was successfully applied five times during open and minimally invasive reconstructive surgery in patients having mitral valve insufficiency. The measurement steps integrate well into the traditional workflow, enhancing the surgeon's three-dimensional perception and generating a suggestion for an appropriate prosthesis.
  
  
  CONCLUSIONS
  The proposed assistance system provides a novel, accurate, and reproducible method for assessing the valvular geometry intraoperatively.
authors.affiliation: Medical and Biological Informatics, German Cancer Research Center (DKFZ), Heidelberg, Germany. sandy.engelhardt@dkfz.de.
authors.forename: Sandy
authors.initials: S
authors.lastname: Engelhardt
authors.affiliation: Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Simone
authors.affiliation: Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Sameer
authors.initials: S
authors.lastname: Al-Maisary
authors.affiliation: Medical and Biological Informatics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Silvio
authors.initials: S
authors.lastname: Kolb
authors.affiliation: Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Karck
authors.affiliation: Medical and Biological Informatics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Meinzer
authors.affiliation: Medical and Biological Informatics, German Cancer Research Center (DKFZ), Heidelberg, Germany.|Department of Computer Science, Mannheim University of Applied Science, Mannheim, Germany.
authors.forename: Ivo
authors.initials: I
authors.lastname: Wolf
mesh_terms: D006801:Humans; D019060:Minimally Invasive Surgical Procedures; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D058386:Mitral Valve Annuloplasty / Q000379:methods*; D008944:Mitral Valve Insufficiency / Q000601:surgery*; D019047:Phantoms, Imaging; D025321:Surgery, Computer-Assisted / Q000379:methods*
keywords: Intraoperative computer-assisted measurements; Mitral valve geometry; Optical tracking