title: Incidence and Risk Factors of Adjacent Cranial Facet Joint Violation Following Pedicle Screw Insertion Using Cortical Bone Trajectory Technique.
abstract: METHODS
  Retrospective study evaluating cranial facet joint violation (FJV) by pedicle screws.
  
  
  OBJECTIVE
  The aim of the study was to determine the incidence and risk factors of FJV following screw placement via cortical bone trajectory (CBT).
  
  
  BACKGROUND
  CBT is a new minimally invasive technique for lumbar pedicle screw insertion that minimizes muscle dissection. Inserting a screw from a more caudal entry point can reduce iatrogenic damage to the cranial facet joint; however, no previous reports exist describing the incidence of FJV secondary to the CBT technique.
  
  
  METHODS
  We reviewed 202 consecutive patients who underwent lumbar pedicle screw instrumentation using CBT from October 2011 to June 2015. Postoperative CT scans were obtained to determine the degree and incidence of FJV. Clinical and imaging data were analyzed to clarify the risk factors of FJV. The detailed positions of the proximal screws were also investigated and compared between the FJV and non-FJV groups.
  
  
  RESULTS
  The incidence of FJV by the proximal screws was 11.8% (48/404), with no occurrence of intra-articular FJV. Multiple logistic regression analysis revealed that age >70 years, vertebral slip >10%, and adjacent facet joint degeneration (Pathria's grade 2 or 3) were independent factors significantly affecting FJV. There were statistically significant differences between the FJV and non-FJV groups in the facet-screw distance (3.2 ± 1.0 vs. 8.1 ± 2.3 mm, P < 0.01), the cranial angle (25.8 ± 6.3° vs. 29.9 ± 7.6°, P < 0.01), and the lamina-screw head distance (5.6 ± 1.6 vs. 6.4 ± 1.9 mm, P < 0.01).
  
  
  CONCLUSIONS
  Lumbar pedicle screw placement via CBT would reduce FJV; however, special care should be taken in patients with age >70 years, vertebral slip >10%, and facet degeneration.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Matsukawa
authors.affiliation: Department of Orthopaedic Surgery, Self-Defense Force Central Hospital, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Tokyo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yato
authors.affiliation: Department of Orthopaedic Surgery, Self-Defense Force Central Hospital, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasao
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Imabayashi
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.affiliation: Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Asazuma
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000071538:Cortical Bone / Q000601:surgery; D005260:Female; D006801:Humans; D015994:Incidence; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D065289:Pedicle Screws / Q000009:adverse effects*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000379:methods; D014057:Tomography, X-Ray Computed; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000601:surgery*