title: Clinical accuracy of 3D fluoroscopy-assisted cervical pedicle screw insertion.
abstract: OBJECTIVE
  Cervical pedicle screw (PS) misplacement leads to injury of the spinal cord, nerve root, and vertebral artery. Recently, several investigators reported on the usefulness of a spinal navigation system that improves the accuracy of PS insertion. In this study, the authors assessed the accuracy of cervical pedicle, lateral mass, and odontoid screw insertions placed using a 3D fluoroscopy navigation system, the Iso-C3D unit.
  
  
  METHODS
  In this prospective analysis of the authors' initial 50 cases of 3D fluoroscopy-assisted cervical screw insertion, the authors inserted 176 PSs, 58 lateral mass screws, and 5 odontoid screws into the C1-7 vertebrae. They placed screws using intraoperative acquisition of data by the isocentric C-arm fluoroscope and a computer navigation system. They obtained postoperative fine-cut CT scans in all patients and assessed the accuracy of screw insertion.
  
  
  RESULTS
  A PS (>or= 3.5 mm) could be inserted into 24 (63%) of 38 pedicles at the level of C-3, 18 (53%) of 34 pedicles at C-4, 30 (65%) of 46 at C-5, 33 (80%) of 41 at C-6, and 43 (100%) of 43 at C-7. Of 176 PSs inserted into vertebrae between C-2 and C-7, 171 screws (97.2%) were classified as Grade 1 (no pedicle perforation), and 5 screws (2.8%) were classified as Grade 2 (screw perforation of the cortex by up to 2 mm). Clinically significant screw deviation in the present study was considered Grade 3 (screw perforation of the cortex by > 2 mm), and this occurred in 0% of the placements.
  
  
  CONCLUSIONS
  In this study, the authors were able to correctly insert cervical PSs using the 3D fluoroscopy and navigation system.
authors.affiliation: Department of Orthopaedic Surgery, Kobe Red Cross Hospital. y-ito@kobe.jrc.or.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ito
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Sugimoto
authors.forename: Masao
authors.initials: M
authors.lastname: Tomioka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Kie
authors.initials: K
authors.lastname: Nakago
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Yagata
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D002574:Cervical Vertebrae; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D038361:Neuronavigation; D011446:Prospective Studies; D015203:Reproducibility of Results; D013122:Spinal Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*