Development and validation of a novel adult spinal deformity surgical invasiveness score: Analysis of 464 patients

Brian J. Neuman, Tamir Ailon, Justin K. Scheer, Eric Klineberg, Daniel M. Sciubba, Amit Jain, Lukas P. Zebala, Peter G. Passias, Alan H. Daniels, Douglas C. Burton, Themi S. Protopsaltis, D. Kojo Hamilton, Christopher P. Ames

Research output: Contribution to journalArticlepeer-review


BACKGROUND: A surgical invasiveness index (SII) has been validated in general spineprocedures but not adult spinal deformity (ASD).OBJECTIVE: To assess the ability of the SII to determine the invasiveness of ASD surgeryand to create and validate a novel ASD index incorporating deformity-specifc factors,which could serve as a standardized metric to compare outcomes and risk stratifcationof different ASD procedures for a given deformity.METHODS: Four hundred sixty-four patients who underwent ASD surgery between 2009and 2012 were identifed in 2 multicenter prospective registries. Multivariable modelsof estimated blood loss (EBL) and operative time were created using deformity-specifcfactors. Beta coefcients derived from these models were used to attribute points toeach component. Scoring was iteratively refned to determine the R2 value of multivariate models of EBL and operative time using adult spinal deformity-surgical (ASD-S) asan independent variable. Similarly, we determined weighting of postoperative changesin radiographical parameters, which were incorporated into another index (adult spinaldeformity-surgical and radiographical [ASD-SR]). The ability of these models to predictsurgical invasiveness was assessed in a validation cohort.RESULTS: Each index was a signifcant, independent predictor of EBL and operative time(P <.001). On multivariate analysis, ASD-S and ASD-SR explained more variability in EBLand operative time than did the SII (P <.001). The ASD-SR explained 21% of the variationin EBL and 10% of the variation in operative time, whereas the SII explained 17% and 3.2%,respectively.CONCLUSION: The ASD-SR, which incorporates deformity-specifc components, moreaccurately predicts the magnitude of ASD surgery than does the SII.

Original languageEnglish (US)
Pages (from-to)847-852
Number of pages6
Issue number6
StatePublished - Jun 1 2018


  • Adult spinal deformity
  • Estimated blood loss
  • Operative time
  • Risk stratifcation
  • Surgical complexity
  • Surgical invasiveness index

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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