title: A multicenter study on accuracy and complications of freehand placement of cervical pedicle screws under lateral fluoroscopy in different pathological conditions: CT-based evaluation of more than 1,000 screws.
abstract: OBJECTIVE
  To conduct a retrospective multicenter study to investigate the accuracy of pedicle screw (PS) placement in the cervical spine by freehand technique and the related complications in various pathological conditions including trauma, rheumatoid arthritis, degenerative conditions and others.
  
  
  METHODS
  283 patients with 1,065 PSs in the cervical spine who were treated at eight spine centers and finished postoperative CT scan were enrolled. The numbers of placed PSs were 608 for trauma, 180 for rheumatoid arthritis (RA), 199 for spondylosis, and 78 for others. Malposition grades on CT image in the axial plane were defined as grade 0 (G-0) correct placement, grade 1 (G-1): malposition by less than half screw diameter, grade 2 (G-2): malposition by more than half screw diameter. The direction of malposition was classified into four categories: medial, lateral, superior and inferior.
  
  
  RESULTS
  Overall malposition rate was 14.8 % (9.6 % in G-1 and 5.3 % in G-2). The highest malposition rate was 26.7 % for RA, followed by 16.6 % for spondylosis, and 11.2 % for trauma. The malposition rate for RA was significantly higher than those for other pathologies. 79.7 % of the malpositioned screws were placed laterally. Though intraoperative vertebral artery injury was observed in two patients with RA, there were no serious complications during a minimal 2-year follow-up.
  
  
  CONCLUSIONS
  Malposition rate of PS placement in the cervical spine by freehand technique was high in rheumatoid patients even when being performed by experienced spine surgeons. Any guidance tools including navigation systems are recommended for placement of cervical PSs in patients with RA.
authors.affiliation: Department of Orthopedic Surgery, Kushiro Rosai Hospital, Kushiro, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hojo
authors.forename: Manabu
authors.initials: M
authors.lastname: Ito
authors.forename: Kota
authors.initials: K
authors.lastname: Suda
authors.forename: Itaru
authors.initials: I
authors.lastname: Oda
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yoshimoto
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Abumi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000601:surgery; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D005471:Fluoroscopy / Q000379:methods / Q000592:standards*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019838:Neck Injuries / Q000000981:diagnostic imaging / Q000601:surgery; D065289:Pedicle Screws; D011184:Postoperative Period; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods / Q000592:standards*; D055009:Spondylosis; D036542:Tomography, Spiral Computed / Q000379:methods / Q000592:standards*