title: Cost-effectiveness of cervical total disc replacement vs fusion for the treatment of 2-level symptomatic degenerative disc disease.
abstract: OBJECTIVE
  Cervical total disc replacement (CTDR) was developed to treat cervical spondylosis, while preserving motion. While anterior cervical discectomy and fusion (ACDF) has been the standard of care for 2-level disease, a randomized clinical trial (RCT) suggested similar outcomes. Cost-effectiveness of this intervention has never been elucidated.
  
  
  OBJECTIVE
  To determine the cost-effectiveness of CTDR compared with ACDF.
  
  
  METHODS
  Data were derived from an RCT that followed up 330 patients over 24 months. The original RCT consisted of multi-institutional data including private and academic institutions. Using linear regression for the current study, health states were constructed based on the stratification of the Neck Disability Index and a visual analog scale. Data from the 12-item Short-Form Health Survey questionnaires were transformed into utilities values using the SF-6D mapping algorithm. Costs were calculated by extracting Diagnosis-Related Group codes from institutional billing data and then applying 2012 Medicare reimbursement rates. The costs of complications and return-to-work data were also calculated. A Markov model was built to evaluate quality-adjusted life-years (QALYs) for both treatment groups. The model adopted a third-party payer perspective and applied a 3% annual discount rate. Patients included in the original RCT had to be diagnosed as having radiculopathy or myeloradiculopathy at 2 contiguous levels from C3-C7 that was unresponsive to conservative treatment for at least 6 weeks or demonstrated progressive symptoms.
  
  
  METHODS
  Incremental cost-effectiveness ratio of CTDR compared with ACDF.
  
  
  RESULTS
  A strong correlation (R2 = 0.6864; P < .001) was found by projecting a visual analog scale onto the Neck Disability Index. Cervical total disc replacement had an average of 1.58 QALYs after 24 months compared with 1.50 QALYs for ACDF recipients. Cervical total disc replacement was associated with $2139 greater average cost. The incremental cost-effectiveness ratio of CTDR compared with ACDF was $24,594 per QALY at 2 years. Despite varying input parameters in the sensitivity analysis, the incremental cost-effectiveness ratio value stays below the threshold of $50,000 per QALY in most scenarios (range, -$58,194 to $147,862 per QALY).
  
  
  CONCLUSIONS
  The incremental cost-effectiveness ratio of CTDR compared with traditional ACDF is lower than the commonly accepted threshold of $50,000 per QALY. This remains true with varying input parameters in a robust sensitivity analysis, reaffirming the stability of the model and the sustainability of this intervention.
authors.affiliation: University of California, Davis, Sacramento.
authors.forename: Jared D
authors.initials: JD
authors.lastname: Ament
authors.affiliation: University of California, Davis, Sacramento.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Spine Institute of Louisiana, Shreveport.
authors.forename: Pierce
authors.initials: P
authors.lastname: Nunley
authors.affiliation: Spine Institute of Louisiana, Shreveport.
authors.forename: Marcus B
authors.initials: MB
authors.lastname: Stone
authors.affiliation: University of California, Davis, Sacramento.
authors.forename: Kee D
authors.initials: KD
authors.lastname: Kim
mesh_terms: D002574:Cervical Vertebrae; D003362:Cost-Benefit Analysis; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000191:economics / Q000601:surgery*; D011788:Quality of Life; D013123:Spinal Fusion / Q000191:economics*; D011795:Surveys and Questionnaires; D059145:Total Disc Replacement / Q000191:economics*; D016896:Treatment Outcome