title: Hospital readmission after spine fusion for adult spinal deformity.
abstract: METHODS
  Retrospective cohort study.
  
  
  OBJECTIVE
  To assess the rate, causes, and risk factors of unplanned hospital readmission after spine fusion for the treatment of adult spinal deformity.
  
  
  BACKGROUND
  Hospital readmissions in the elderly are common, and with increasing emphasis on the quality of health care, readmission rates are used to assess hospital performance. Spine surgery has seen rapidly increased utilization during the past 2 decades. Surgical treatments of complex spinal deformity are known to have higher rates of complications than other types of spine surgery. However, there are no reports describing the rates and causes of hospital readmission after deformity surgery.
  
  
  METHODS
  Patients were identified at a single institution from 2006 through 2011 that received a spine fusion for the treatment of adult spinal deformity. All hospital readmissions within 90 days of discharge were reviewed for cause. Unplanned readmission rates were calculated via Kaplan-Meier failure analysis. Rates were compared across patients receiving different lengths of spine fusion (short: 2-3 vertebra, medium: 4-8, long: 9 or more). Risk factors were assessed using a Cox proportional hazards multivariate model.
  
  
  RESULTS
  Eight hundred thirty-six patients were enrolled (111 short, 402 medium, and 323 long fusions). The overall unplanned readmission rate was 8.4% at 30 days and 12.3% at 90 days. Patients with long spine fusion had higher rates of readmission than patients with medium or short length fusions. Surgical site infection accounted for 45.6% of readmissions. Risk factors for readmission include longer fusion length, higher patient severity of illness, and specific medical comorbidities.
  
  
  CONCLUSIONS
  Unplanned hospital readmissions after spine fusion for adult spinal deformity are common, and are most often due to surgical site infection. Patient medical comorbidities are an important part of assessing risk and can be used by providers and patients to better assess individual risk prior to treatment.
authors.affiliation: Departments of *Orthopaedic Surgery and †Neurological Surgery, University of California, San Francisco, CA.
authors.forename: William W
authors.initials: WW
authors.lastname: Schairer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Carrer
authors.forename: Vedat
authors.initials: V
authors.lastname: Deviren
authors.forename: Serena S
authors.initials: SS
authors.lastname: Hu
authors.forename: Steven
authors.initials: S
authors.lastname: Takemoto
authors.forename: Praveen
authors.initials: P
authors.lastname: Mummaneni
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.forename: Christopher
authors.initials: C
authors.lastname: Ames
authors.forename: Shane
authors.initials: S
authors.lastname: Burch
authors.forename: Bobby
authors.initials: B
authors.lastname: Tay
authors.forename: Aenor
authors.initials: A
authors.lastname: Sawyer
authors.forename: Sigurd H
authors.initials: SH
authors.lastname: Berven
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000639:trends*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012600:Scoliosis / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects*; D013530:Surgical Wound Infection / Q000175:diagnosis / Q000453:epidemiology; D016896:Treatment Outcome