title: Comparison of Patient Outcomes and Cost of Overlapping Versus Nonoverlapping Spine Surgery.
abstract: BACKGROUND
  Overlapping surgery recently has gained significant media attention, but there are limited data on its safety and efficacy. To date, there has been no analysis of overlapping surgery in the field of spine. Our goal was to compare overlapping versus nonoverlapping spine surgery patient outcomes and cost.
  
  
  METHODS
  A retrospective review was undertaken of 2319 spine surgeries (n = 848 overlapping; 1471 nonoverlapping) performed by 3 neurosurgery attendings from 2012 to 2015 at the University of California San Francisco. Collected variables included patient age, sex, insurance, American Society of Anesthesiology score, severity of illness, risk of mortality, procedure type, surgeon, day of surgery, source of transfer, admission type, overlapping versus nonoverlapping surgery (≥1 minute of overlapping procedure time), Medicare-Severity Diagnosis-Related Group, osteotomy, and presence of another attending/fellow/resident. Univariate, then multivariate mixed-effect models were used to evaluate the effect of the collected variables on the following outcomes: procedure time, estimated blood loss, length of stay, discharge status, 30-day mortality, 30-day unplanned readmission, unplanned return to OR, and total hospital cost.
  
  
  RESULTS
  Urgent spine cases were more likely to be done in an overlapping fashion (all P < 0.01). After we adjusted for patient demographics, clinical indicators, and procedure characteristics, overlapping surgeries had longer procedure times (estimate = 26.17; P < 0.001) and lower rates of discharge to home (odds ratio 0.65; P < 0.001), but equivalent rates of 30-day mortality, readmission, return to the operating room, estimated blood loss, length of stay, and total hospital cost (all P = ns).
  
  
  CONCLUSIONS
  Overlapping spine surgery may be performed safely at our institution, although continued monitoring of patient outcomes is necessary. Overlapping surgery does not lead to greater hospital costs.
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA. Electronic address: zygourakisc@neurosurg.ucsf.edu.
authors.forename: Corinna C
authors.initials: CC
authors.lastname: Zygourakis
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Saman
authors.initials: S
authors.lastname: Sizdahkhani
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Malla
authors.initials: M
authors.lastname: Keefe
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Janelle
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
mesh_terms: D016063:Blood Loss, Surgical; D005260:Female; D017721:Hospital Costs; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D061646:Operative Time; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000191:economics / Q000379:methods* / Q000706:statistics & numerical data*; D010351:Patient Discharge; D010359:Patient Readmission; D012086:Reoperation; D012189:Retrospective Studies; D013131:Spine / Q000601:surgery*; D016896:Treatment Outcome
keywords: Concurrent surgery; Cost analysis; Overlapping surgery; Patient outcomes; Patient safety; Running two rooms; Spine surgery