title: Mid-term results of computer-assisted cervical pedicle screw fixation.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  The present study aimed to evaluate mid-term results of cervical pedicle screw (CPS) fixation for cervical instability.
  
  
  BACKGROUND
  CPS fixation has widely used in the treatment of cervical spinal instability from various causes; however, there are few reports on mid-term surgical results of CPS fixation.
  
  
  METHODS
  Record of 19 patients who underwent cervical and/or upper thoracic (C2-T1) pedicle screw fixation for cervical instability was reviewed. The mean observation period was 90.2 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 years after surgery. Postoperative computerized tomography was used to determine the accuracy of screw placement. Visual analog scale (VAS) for neck pain and radiological evidence of adjacent segment degeneration (ASD) at the 5-year follow-up were also evaluated.
  
  
  RESULTS
  Mean JOA score was significantly improved from 9.0 points before surgery to 12.8 at 5 years after surgery (p=0.001). The C2-7 lordotic angle of the neutral position improved from 6.4° to 7.8° at 5 years after surgery, but this was not significant. The major perforation rate was 5.0%. There were no clinically significant complications such as vertebral artery injury, spinal cord injury, or nerve root injury caused by any screw perforation. Mean VAS for neck pain was 49.4 at 5 years after surgery. The rate of ASD was 21.1%.
  
  
  CONCLUSIONS
  Our mid-term results showed that CPS fixation was useful for treating cervical instability. Severe complications were prevented with the assistance of a computed tomography-based navigation system.
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Uehara
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Takahashi
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Keijiro
authors.initials: K
authors.lastname: Mukaiyama
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Shugo
authors.initials: S
authors.lastname: Kuraishi
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Ikegami
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Futatsugi
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Ogihara
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hashidate
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hirabayashi
authors.affiliation: Department of Orthopaedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
keywords: Adjacent segment degeneration; Cervical instability; Cervical pedicle screw; Mid-term results