title: The Incidence of Potential Candidates for Total Disc Replacement among Lumbar and Cervical Fusion Patient Populations.
abstract: METHODS
  Retrospective chart review.
  
  
  OBJECTIVE
  To evaluate the incidence of potential total disc replacement (TDR) candidates among cervical and lumbar fusion patient populations using strict Food and Drug Administration (FDA) criteria and with relative exclusion criteria removed.
  
  
  BACKGROUND
  Recent studies suggest that the potential percentage of patients that are candidates for TDR ranges from 0-5% in lumbar fusions and 43% in cervical fusions.
  
  
  METHODS
  We performed a retrospective chart review of 280 consecutive patients who had lumbar (n = 174) and cervical (n = 106) fusion or TDR performed by one of four independent adult orthopaedic spine surgeons. Charts were screened for investigational device exemption (IDE) inclusion/exclusion criteria and later reanalyzed excluding relative exclusion criteria, such as history of chronic medical illness, twolevel disease (cervical cases), and history of prior fusion surgery in the anatomic region.
  
  
  RESULTS
  Of the 174 lumbar surgeries, 10 were TDR with Prodisc-L and 164 were lumbar fusions. The most common TDR exclusion criteria were lytic spondylolisthesis or spinal stenosis (47.7% of patients) and more than 2 level degenerative disc disease (37.9%). 14.9% had no IDE exclusion criteria and would be considered candidates for TDR. After excluding the relative lumbar exclusion criteria, this percentage increased to 25.8%. Of the 106 cervical cases, 3 had a TDR with Prodisc-C and 103 had a cervical fusion. Twenty eight percent had no IDE exclusion criteria and would be considered candidates for cervical TDR.
  
  
  CONCLUSIONS
  A larger percentage of cervical fusion candidates are potential candidates for TDR (28%) than lumbar fusion candidates (14.9%) based on the strict IDE criteria.
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY 10003, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Quirno
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Goldstein
authors.forename: John A
authors.initials: JA
authors.lastname: Bendo
authors.forename: Yong
authors.initials: Y
authors.lastname: Kim
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Spivak