title: Precision insertion of percutaneous sacroiliac screws using a novel augmented reality-based navigation system: a pilot study.
abstract: Augmented reality (AR) enables superimposition of virtual images onto the real world. The aim of this study is to present a novel AR-based navigation system for sacroiliac screw insertion and to evaluate its feasibility and accuracy in cadaveric experiments.
  
  
  
  Six cadavers with intact pelvises were employed in our study. They were CT scanned and the pelvis and vessels were segmented into 3D models. The ideal trajectory of the sacroiliac screw was planned and represented visually as a cylinder. For the intervention, the head mounted display created a real-time AR environment by superimposing the virtual 3D models onto the surgeon's field of view. The screws were drilled into the pelvis as guided by the trajectory represented by the cylinder. Following the intervention, a repeat CT scan was performed to evaluate the accuracy of the system, by assessing the screw positions and the deviations between the planned trajectories and inserted screws.
  
  
  
  Post-operative CT images showed that all 12 screws were correctly placed with no perforation. The mean deviation between the planned trajectories and the inserted screws was 2.7 ± 1.2 mm at the bony entry point, 3.7 ± 1.1 mm at the screw tip, and the mean angular deviation between the two trajectories was 2.9° ± 1.1°. The mean deviation at the nerve root tunnels region on the sagittal plane was 3.6 ± 1.0 mm.
  
  
  
  This study suggests an intuitive approach for guiding screw placement by way of AR-based navigation. This approach was feasible and accurate. It may serve as a valuable tool for assisting percutaneous sacroiliac screw insertion in live surgery.
authors.affiliation: Orthopaedic Traumatology, Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
authors.forename: Huixiang
authors.initials: H
authors.lastname: Wang
authors.affiliation: Orthopaedic Traumatology, Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Musculoskeletal Lab, Department of Surgery and Cancer, Imperial College London, Charing Cross Hospital, London, UK.
authors.forename: Anthony Peng Yew
authors.initials: AP
authors.lastname: Leong
authors.affiliation: School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Lu
authors.initials: L
authors.lastname: Xu
authors.affiliation: School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China. xiaojunchen@163.com.
authors.forename: Xiaojun
authors.identifier: 0000-0002-4616-3062
authors.initials: X
authors.lastname: Chen
authors.affiliation: Orthopaedic Traumatology, Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China. wangqiugen@outlook.com.
authors.forename: Qiugen
authors.initials: Q
authors.lastname: Wang
mesh_terms: D001863:Bone Screws; D002102:Cadaver; D006801:Humans; D021621:Imaging, Three-Dimensional; D010865:Pilot Projects; D012446:Sacroiliac Joint / Q000601:surgery; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed
keywords: Augmented reality; Computer assisted surgery; Head mounted display; Sacroiliac screw insertion; Three-dimensional navigation