title: A Novel Quality-of-Life Utility Index in Patients With Multilevel Cervical Degenerative Disc Disease: Comparison of Anterior Cervical Discectomy and Fusion With Total Disc Replacement.
abstract: METHODS
  Decision analysis from prior randomized controlled trial (RCT) data.
  
  
  OBJECTIVE
  To describe the importance of developing baseline utility indices while identifying effective treatment options for cervical spine disease.
  
  
  BACKGROUND
  Cervical total disc replacement (CTDR) was developed to treat cervical spondylosis while preserving motion. Although anterior cervical discectomy and fusion (ACDF) has been the standard of care, a recent RCT suggested similar outcomes for 2-level disease. The quality-of-life benefit afforded by both CTDR and ACDF has never been fully elucidated. The purpose of our investigation was to better define the changes in utility and perceived value for patients undergoing these procedures.
  
  
  METHODS
  Data were derived from LDR's RCT comparing CTDR and ACDF for 2-level cervical disc disease. Using linear regression, we constructed health states on the basis of the stratification of clinical outcomes used in the RCT, namely, neck disability index and visual analogue scale. Data from SF-12 questionnaires, completed preoperatively and at each follow-up visit, were transformed into utilities using the SF-6D mapping algorithm. SAS v.9.3 was used for the analyses.
  
  
  RESULTS
  A strong correlation (R = 0.6864, P < 0.0001) was found between neck disability index and visual analogue scale. We constructed 5 distinct health states by projecting neck disability index intervals onto visual analogue scale. A poorer health state was associated with a lower mean utility value whereas a higher health state was associated with a higher mean utility value (P < 0.0001). The difference in preoperative utility between 2-level ACDF and CTDR was not significant (P = 0.1982), and yet, the difference in the postoperative utility between the cohorts was significant (P < 0.05) at every time point collected from 6 to 60 months.
  
  
  CONCLUSIONS
  This is the first instance in which distinct utility values have been derived for validated health states related to cervical spine disease. There is substantial potential for these to become baseline future indices for cost-utility analyses in similar populations.
  
  
  METHODS
  1.
authors: *University of California Davis, Sacramento, CA; and †Ben-Gurion University, Beer-Sheva, Israel.
authors: Jared D
authors: JD
authors: Ament
authors: Zhuo
authors: Z
authors: Yang
authors: Yingjia
authors: Y
authors: Chen
authors: Ross S
authors: RS
authors: Green
authors: Kee D
authors: KD
authors: Kim
mesh_terms: D004185:Disability Evaluation; D017586:Diskectomy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000453:epidemiology* / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000453:epidemiology* / Q000601:surgery*; D011183:Postoperative Complications; D011788:Quality of Life; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D059145:Total Disc Replacement / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*