title: Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging: A Spine Cadaveric Feasibility and Accuracy Study.
abstract: METHODS
  A cadaveric laboratory study.
  
  
  OBJECTIVE
  The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN).
  
  
  BACKGROUND
  Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine.
  
  
  METHODS
  ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches.
  
  
  RESULTS
  ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method.
  
  
  CONCLUSIONS
  ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement.
  
  
  METHODS
  N/A.
authors: Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden.
authors: Adrian
authors: A
authors: Elmi-Terander
authors: Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden.
authors: Halldor
authors: H
authors: Skulason
authors: Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden.
authors: Michael
authors: M
authors: Söderman
authors: Department of Pediatric Interventional Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
authors: John
authors: J
authors: Racadio
authors: Department of Image Guided Therapy Systems, Philips Healthcare, Best, the Netherlands.
authors: Robert
authors: R
authors: Homan
authors: Department of Image Guided Therapy Systems, Philips Healthcare, Best, the Netherlands.
authors: Drazenko
authors: D
authors: Babic
authors: Department of Image Guided Therapy Systems, Philips Healthcare, Best, the Netherlands.
authors: Nijs
authors: N
authors: van der Vaart
authors: Department of Image Guided Therapy Systems, Philips Healthcare, Best, the Netherlands.
authors: Rami
authors: R
authors: Nachabe
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008159:Lumbar Vertebrae / Q000601:surgery*; D019637:Orthopedic Procedures / Q000379:methods*; D065289:Pedicle Screws; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013904:Thoracic Vertebrae / Q000601:surgery*