title: A fluoroscopy-based planning and guidance software tool for minimally invasive hip refixation by cement injection.
abstract: OBJECTIVE
  In orthopaedics, minimally invasive injection of bone cement is an established technique. We present HipRFX, a software tool for planning and guiding a cement injection procedure for stabilizing a loosening hip prosthesis. HipRFX works by analysing a pre-operative CT and intraoperative C-arm fluoroscopic images.
  
  
  METHODS
  HipRFX simulates the intraoperative fluoroscopic views that a surgeon would see on a display panel. Structures are rendered by modelling their X-ray attenuation. These are then compared to actual fluoroscopic images which allow cement volumes to be estimated. Five human cadaver legs were used to validate the software in conjunction with real percutaneous cement injection into artificially created periprothetic lesions.
  
  
  RESULTS
  Based on intraoperatively obtained fluoroscopic images, our software was able to estimate the cement volume that reached the pre-operatively planned targets. The actual median target lesion volume was 3.58 ml (range 3.17-4.64 ml). The median error in computed cement filling, as a percentage of target volume, was 5.3% (range 2.2-14.8%). Cement filling was between 17.6 and 55.4% (median 51.8%).
  
  
  CONCLUSIONS
  As a proof of concept, HipRFX was capable of simulating intraoperative fluoroscopic C-arm images. Furthermore, it provided estimates of the fraction of injected cement deposited at its intended target location, as opposed to cement that leaked away. This level of knowledge is usually unavailable to the surgeon viewing a fluoroscopic image and may aid in evaluating the success of a percutaneous cement injection intervention.
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. fmalan@medvis.org.|Department of Intelligent Systems, Delft University of Technology, P.O. Box 5031, 2600 GA, Delft, The Netherlands. fmalan@medvis.org.|Department of Orthopaedics, J11-R, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. fmalan@medvis.org.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Malan
authors.affiliation: Division of Applied Mathematics, University of Stellenbosch, Stellenbosch, 7602, South Africa.
authors.forename: Stéfan J
authors.initials: SJ
authors.lastname: van der Walt
authors.affiliation: Department of Intelligent Systems, Delft University of Technology, P.O. Box 5031, 2600 GA, Delft, The Netherlands.|Department of Biomedical Engineering, Technische Universiteit Eindhoven, 5600 MB, Eindhoven, The Netherlands.
authors.forename: Renata G
authors.initials: RG
authors.lastname: Raidou
authors.affiliation: Department of Intelligent Systems, Delft University of Technology, P.O. Box 5031, 2600 GA, Delft, The Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: van den Berg
authors.affiliation: Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Berend C
authors.initials: BC
authors.lastname: Stoel
authors.affiliation: Department of Intelligent Systems, Delft University of Technology, P.O. Box 5031, 2600 GA, Delft, The Netherlands.|Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Charl P
authors.initials: CP
authors.lastname: Botha
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Rob G H H
authors.initials: RG
authors.lastname: Nelissen
authors.affiliation: Department of Orthopaedics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.|Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Valstar
mesh_terms: D000465:Algorithms; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D001843:Bone Cements / Q000009:adverse effects*; D002102:Cadaver; D003198:Computer Simulation; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D010934:Planning Techniques; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging / Q000601:surgery*; D012086:Reoperation / Q000379:methods; D012984:Software
chemical_list: D001843:Bone Cements
keywords: Digitally reconstructed radiograph; Fluoroscopy; Hip arthroplasty; Percutaneous; Pre-operative planning; Simulation; X-ray