title: Acute hospital costs after minimally invasive versus open lumbar interbody fusion: data from a US national database with 6106 patients.
abstract: METHODS
  Retrospective multi-institutional database review.
  
  
  OBJECTIVE
  To determine if minimally invasive interbody fusion is associated with cost savings when compared with open surgery.
  
  
  BACKGROUND
  Minimally invasive spine (MIS) surgeries are increasingly recognized as equivalent to open procedures. Although these techniques have been advocated for reducing pain, disability, and length of hospitalization, to date there has been little data demonstrating these benefits.
  
  
  METHODS
  This study analyzed inpatient hospital records from the Premier Perspective database (2002 to 2009), including patients who underwent a posterior lumbar fusion with interbody cage placement by ICD-9 code, and had implant charge codes that allowed determination if MIS pedicle screws were utilized. Exclusion criteria included a refusion surgery, deformity, >2 levels, and anterior fusion. Total costs were adjusted for covariates (age, sex, race, hospital geography and setting, payor, and comorbidities) using an analysis of covariance model.
  
  
  RESULTS
  A total of 6106 patients were identified (1667 MIS and 4439 open). Length of stay (LOS) for 1-level MIS surgery averaged of 3.35 days versus 3.6 days for open surgery (P≤0.006). For 2-level MIS surgery LOS averaged of 3.4 days versus 4.03 days for open surgery (P≤0.001). Total inflation-adjusted acute hospitalization cost averaged $29,187 for 1-level MIS procedures versus $29,947 for open surgery, a nonsignificant difference (P=0.55). Total inflation-adjusted acute hospitalization cost averaged $2106 lower for 2-level MIS surgery (total costs of $33,879 for MIS vs. $35,984 for open surgery, P=0.0023). Cost savings were attributable primarily to lower room and board ($857), operating room ($359), pharmacy ($304), and laboratory ($166) costs in the MIS group. High variances in the 2-level open surgery with prolonged hospital stay also accounted for overall cost differences.
  
  
  CONCLUSIONS
  This data from a large nationwide sample of hospitalizations demonstrates that MIS lumbar interbody fusion results in a statistically significant reduction in hospital LOS and a reduction in total hospital costs with 2-level surgery after adjusting for significant covariates. The majority of cost savings from MIS surgery were due to more rapid mobilization and discharge, as well as a reduction in outliers with extended hospitalizations.
authors.affiliation: Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA. mwang2@med.miami.edu
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Wang
authors.forename: Jason
authors.initials: J
authors.lastname: Lerner
authors.forename: James
authors.initials: J
authors.lastname: Lesko
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McGirt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D005260:Female; D017721:Hospital Costs; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D038801:International Classification of Diseases / Q000191:economics; D007902:Length of Stay / Q000191:economics; D017116:Low Back Pain / Q000191:economics* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000191:economics* / Q000379:methods; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000191:economics* / Q000379:methods; D016896:Treatment Outcome; D014481:United States