title: Comparison of cranial facet joint violation rates between open and percutaneous pedicle screw placement using intraoperative 3-D CT (O-arm) computer navigation.
abstract: METHODS
  Retrospective study comparing cranial facet joint violation rates of open and percutaneous pedicle screws inserted using 3-dimensional image-guidance.
  
  
  OBJECTIVE
  To determine the rate of cranial facet joint violation in intraoperative computed tomography (CT) image-guided lumbar pedicle screw instrumentation and compare facet joint violation rates between CT image-guided open and percutaneous techniques.
  
  
  BACKGROUND
  Facet joint violation by pedicle screws can potentially result in a higher rate of adjacent segment degeneration. Reported cranial facet joint violation rates range from 7% to 100%. Intraoperative image-guidance, which has enhanced pedicle screw placement accuracy, may aid in avoiding impingement of the cranial facet joints.
  
  
  METHODS
  We reviewed 188 cases of 3-dimensional image-guided lumbar pedicle screw instrumentation from November 2006 to December 2011. The cranial screws of each construct were graded by 3 reviewers according to the Seo classification (0 = no impingement; 1 = screw head in contact/suspected to be in contact with joint; 2 = screw clearly invaded the joint) on intraoperative axial CT images. If there was a difference in evaluation, a consensus was reached to arrive at a single grade. The χ2 test was used to determine significance between the open and percutaneous group (α = 0.05).
  
  
  RESULTS
  A total of 370 screws (245 open, 125 percutaneous) were graded. Overall facet joint violation rate was 18.9% (grade 1 = 16.2%, grade 2 = 2.7%). Open technique (grade 1 = 22.4%, grade 2 = 4.1%) had a significantly higher violation rate than percutaneous technique (grade 1 = 4%, grade 2 = 0%) (P < 0.0001). There is a trend of an increasing likelihood of facet joint violation from L1 to L5.
  
  
  CONCLUSIONS
  The use of intraoperative CT image-guidance in lumbar pedicle screw placement resulted in a facet joint violation rate at the lower end of the reported range in literature. The percutaneous technique has a significantly lower facet violation rate than the open technique.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Sharon C
authors.initials: SC
authors.lastname: Yson
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Sembrano
authors.forename: Peter C
authors.initials: PC
authors.lastname: Sanders
authors.forename: Edward Rainier G
authors.initials: ER
authors.lastname: Santos
authors.forename: Charles Gerald T
authors.initials: CG
authors.lastname: Ledonio
authors.forename: David W
authors.initials: DW
authors.lastname: Polly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D015641:Radiography, Interventional; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000009:adverse effects; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult; D021801:Zygapophyseal Joint / Q000601:surgery*