title: Comparison of superior-level facet joint violations during open and percutaneous pedicle screw placement.
abstract: BACKGROUND
  Superior-level facet joint violation by pedicle screws may result in increased stress to the level above the instrumentation and may contribute to adjacent segment disease. Previous studies have evaluated facet joint violations in open or percutaneous screw cases, but there are no reports describing a direct institutional comparison.
  
  
  OBJECTIVE
  To compare the incidence of superior-level facet violation for open vs percutaneous pedicle screws and to evaluate patient and surgical factors that affect this outcome.
  
  
  METHODS
  We reviewed 279 consecutive patients who underwent an index instrumented lumbar fusion from 2007 to 2011 for degenerative spine disease with stenosis with or without spondylolisthesis. We used a computed tomography grading system that represents progressively increasing grades of facet joint violation. Patient and surgical factors were evaluated to determine their impact on facet violation.
  
  
  RESULTS
  Our cohort consisted of 126 open and 153 percutaneous cases. Percutaneous procedures had a higher overall violation grade (P = .02) and a greater incidence of high-grade violations (P = .006) compared with open procedures. Bivariate analysis showed significantly greater violations in percutaneous cases for age < 65 years, obesity, pedicle screws at L4, and 1- and 2-level surgeries. Multivariate analysis showed the percutaneous approach and depth of the spine to be independent risk factors for high-grade violations.
  
  
  CONCLUSIONS
  This study demonstrates greater facet violations for percutaneously placed pedicle screws compared with open screws.
authors: Division of Neurosurgery, Department of Surgery, Duke University School of Medicine, Durham, North Carolina 27710, USA.
authors: Ranjith
authors: R
authors: Babu
authors: Jong G
authors: JG
authors: Park
authors: Ankit I
authors: AI
authors: Mehta
authors: Tony
authors: T
authors: Shan
authors: Peter M
authors: PM
authors: Grossi
authors: Christopher R
authors: CR
authors: Brown
authors: William J
authors: WJ
authors: Richardson
authors: Robert E
authors: RE
authors: Isaacs
authors: Carlos A
authors: CA
authors: Bagley
authors: Maragatha
authors: M
authors: Kuchibhatla
authors: Oren N
authors: ON
authors: Gottfried
mesh_terms: D001863:Bone Screws / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects*; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D021801:Zygapophyseal Joint / Q000601:surgery*