title: Revision Rate After Adult Deformity Surgery.
abstract: METHODS
  Epidemiological study.
  
  
  OBJECTIVE
  To establish the revision rate of adult spinal deformity surgery.
  
  
  BACKGROUND
  Historically, surgical treatment of adult spinal deformity was limited by inadequate correction and high complication rates. More recently, improved techniques have produced more consistent clinical benefit. However, the need for revision surgery remains a persistent and inadequately defined problem.
  
  
  METHODS
  Patients who had multilevel spinal fusion for adult spinal deformity were identified from a national insurance database containing private payer and Medicare records using International Classification of Diseases, Ninth Revision or Current Procedural Terminology codes from 2005 to 2011. Revision procedures were identified based on codes for spinal instrumentation and fusion.
  
  
  RESULTS
  The Medicare sample included 1,879 patients (1,329 females and 550 males). The revision rate in this cohort was 6% in Year 1 postoperatively, 6% in Year 2, 4% in Year 3, and 3% in Year 4, for a cumulative 19% revision rate. In the private payer database, 803 patients (559 females and 244 males) were identified. Revision rate was 10% in Year 1 postoperatively, 3% in Year 2, 2% in Year 3, and 1% in Year 4, for a cumulative 16% revision rate. Pooling the databases yielded an overall 18% revision rate at 4 years postoperatively. Fewer revisions were noted at 1 year postoperatively in the Medicare sample and the 1-year revision rate was inversely proportional to age across the entire cohort. The revision rate equalized across age groups over time such that no differences were seen at 4 years postoperatively.
  
  
  CONCLUSIONS
  The value of an intervention depends on efficacy, safety, and durability. Despite improvements in technique and clinical outcome, an 18% revision rate at 4 years postoperatively is not sustainable from either a clinical or an economic standpoint. This study establishes a benchmark for the critical effort that is needed to reduce the revision rate in adult spinal deformity surgery.
authors.affiliation: Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA; Department of Orthopaedic Surgery, University of Louisville School of Medicine, 550 S. Jackson Street, 1st Floor ACB, Louisville, KY 40202, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Glassman
authors.affiliation: Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA; Department of Orthopaedic Surgery, University of Louisville School of Medicine, 550 S. Jackson Street, 1st Floor ACB, Louisville, KY 40202, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Dimar
authors.affiliation: Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202, USA. Electronic address: leah.carreon@nortonhealthcare.org.
authors.forename: Leah Y
authors.initials: LY
authors.lastname: Carreon
keywords: Adult spinal deformity; Complications; Revisions; Surgery