title: A fluorolaser navigation system to guide linear surgical tool insertion.
abstract: OBJECTIVE
  Conventional navigation systems for minimally invasive orthopedic surgery require a secondary monitor to display guidance information generated with CT or MRI images. Newer systems use augmented reality to project surgical plans into binocular glasses. These surgical procedures are often mentally challenging and cumbersome to perform.
  
  
  METHODS
  A comprehensive surgical navigation system for direct guidance while minimizing radiation exposure was designed and built. System accuracy was evaluated using in vitro needle insertion experiments. The fluoroscopic-based navigation technique is combined with an existing laser guidance technique. As a result, the combined system is capable of surgical planning using two or more X-ray images rather than CT or MRI scans. Guidance information is directly projected onto the patient using two laser beams and not via a secondary monitor.
  
  
  RESULTS
  We performed 15 in vitro needle insertion experiments as well as 6 phantom pedicle screw insertion experiments to validate navigation system accuracy. The planning accuracy of the system was found to be 2.32 mm and 2.28°, while its overall guidance accuracy was found to be 2.40 mm and 2.39°. System feasibility was demonstrated by successfully performing percutaneous pin insertion on phantoms.
  
  
  CONCLUSIONS
  Quantitative and qualitative evaluations of the fluorolaser navigation system show that it can support accurate guidance and intuitive surgical tool insertion procedures without preoperative 3D image volumes and registration processes.
authors.affiliation: Graduate School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-8656, Japan. jliang@image.t.u-tokyo.ac.jp
authors.forename: Jack T
authors.initials: JT
authors.lastname: Liang
authors.forename: Takehito
authors.initials: T
authors.lastname: Doke
authors.forename: Shinya
authors.initials: S
authors.lastname: Onogi
authors.forename: Satoru
authors.initials: S
authors.lastname: Ohashi
authors.forename: Isao
authors.initials: I
authors.lastname: Ohnishi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakuma
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakajima
mesh_terms: D002138:Calibration; D005240:Feasibility Studies; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007834:Lasers; D019637:Orthopedic Procedures / Q000379:methods*; D019047:Phantoms, Imaging; D012984:Software; D025321:Surgery, Computer-Assisted / Q000379:methods*