title: Anterior cervical fusion assessment using reconstructed computed tomographic scans: surgical confirmation of 254 segments.
abstract: METHODS
  Retrospective study developing diagnostic criteria.
  
  
  OBJECTIVE
  To validate 2 computed tomography-based findings, extragraft bone bridging (ExGBB) and intragraft bone bridging (InGBB), as diagnostic criteria for anterior cervical fusion using subsequent surgical confirmation and to demonstrate the different diagnostic accuracy on the basis of the graft material used.
  
  
  BACKGROUND
  The accuracy and the methodology for evaluating bone bridging on computed tomographic scans to determine anterior cervical fusion status have not been validated or standardized.
  
  
  METHODS
  One hundred ten patients with 254 surgically explored segments along with reconstructed computed tomographic scans were included. Bone bridging at each cervical level was assessed for ExGBB and InGBB. ExGBB was defined as complete cortical bridging at any peripheral margins (anterior, posterior, left, or right) of the operated disc space, outside of the graft. InGBB was defined as cortical or trabecular bridging within the confines of the graft only. ExGBB and InGBB were serially evaluated on reformatted coronal and sagittal views by 3 independent raters. The reliabilities and validities correlated with surgical exploration were evaluated.
  
  
  RESULTS
  Surgical exploration revealed 123 fused and 131 pseudarthrosis segments. The reliability of 3 raters showed near perfect agreement for ExGBB and substantial agreement for InGBB. ExGBB also had higher validity for all raters than did InGBB. The autocortical graft group had the highest accuracy for both InGBB and ExGBB, with both values being nearly identical. The allograft group had the next highest validity values. For the cage group, InGBB had the lowest specificity (53.2%) and positive predictive value (35.5%), whereas ExGBB had 100% sensitivity and negative predictive value.
  
  
  CONCLUSIONS
  ExGBB seems to be a far more reliable and accurate to determine anterior cervical fusion. The diagnostic criteria using bone bridging should be different based on the intradiscal materials. With cages in particular, InGBB seems unreliable and ExGBB is necessary to determine anterior cervical fusion.
authors.affiliation: *Department of Orthopaedic Surgery, Chung-Ang University, College of Medicine, Seoul, Korea; and †Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO.
authors.forename: Kwang-Sup
authors.initials: KS
authors.lastname: Song
authors.forename: Piyaskulkaew
authors.initials: P
authors.lastname: Chaiwat
authors.forename: Han Jo
authors.initials: HJ
authors.lastname: Kim
authors.forename: Addisu
authors.initials: A
authors.lastname: Mesfin
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Park
authors.forename: K Daniel
authors.initials: KD
authors.lastname: Riew
mesh_terms: D002574:Cervical Vertebrae / Q000601:surgery*; D017586:Diskectomy / Q000379:methods; D005260:Female; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000601:surgery; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013123:Spinal Fusion / Q000379:methods; D014057:Tomography, X-Ray Computed