title: Timing of Complications After Spinal Fusion Surgery.
abstract: METHODS
  Retrospective cohort study.
  
  
  OBJECTIVE
  To characterize the timing of complications after spinal fusion procedures.
  
  
  BACKGROUND
  Despite many publications on risk factors for complications after spine surgery, there are few publications on the timing at which such complications occur.
  
  
  METHODS
  Patients undergoing anterior cervical decompression and fusion (ACDF) or posterior lumbar fusion (PLF; with or without interbody) procedures during 2011-2013 were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. For each of 8 different complications, the median time from surgery until complication was determined, along with the interquartile range and middle 80%.
  
  
  RESULTS
  A total of 12,067 patients undergoing ACDF and 11,807 patients undergoing PLF were identified. For ACDF, the median day of diagnosis (and interquartile range; middle 80%) for anemia requiring transfusion was 0 (0-1; 0-2), myocardial infarction 2 (1-5; 0-15), pneumonia 4 (2-9; 1-14), pulmonary embolism 5 (2-9; 1-10), deep vein thrombosis 10.5 (7-16.5; 5-21), sepsis 10.5 (4-18; 1-23), surgical site infection 13 (8-19; 5-25), and urinary tract infection 17 (8-22; 4-26). For PLF, the median day of diagnosis (and interquartile range; middle 80%) for anemia requiring transfusion was 0 (0-1; 0-2), myocardial infarction 2 (1-4; 1-8), pneumonia 4 (2-9; 1-17), pulmonary embolism 5 (3-11; 2-17), urinary tract infection 7 (4-14; 2-23), deep vein thrombosis 8 (5-16; 3-20), sepsis 9 (4-16; 2-22), and surgical site infection 17 (13-22; 9-27).
  
  
  CONCLUSIONS
  These precisely described postoperative time periods enable heightened clinical awareness among spine surgeons. Spine surgeons should have the lowest threshold for testing for each complication during the time period of greatest risk. Authors, reviewers, and surgeons utilizing research on postoperative complications should carefully consider the impact that the duration of follow-up has on study results.
  
  
  METHODS
  3.
authors.affiliation: *Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL †Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT; and ‡Departments of Orthopaedic Surgery and Neurological Surgery, Thomas Jefferson University and The Rothman Institute, Philadelphia, PA.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Bohl
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Webb
authors.forename: Adam M
authors.initials: AM
authors.lastname: Lukasiewicz
authors.forename: Andre M
authors.initials: AM
authors.lastname: Samuel
authors.forename: Bryce A
authors.initials: BA
authors.lastname: Basques
authors.forename: Junyoung
authors.initials: J
authors.lastname: Ahn
authors.forename: Kern
authors.initials: K
authors.lastname: Singh
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Grauer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D011655:Pulmonary Embolism / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects* / Q000379:methods; D066231:Surgeons; D013997:Time Factors; D055815:Young Adult