title: Risk factors for postoperative retropharyngeal hematoma after anterior cervical spine surgery.
abstract: METHODS
  Retrospective review of prospective database.
  
  
  OBJECTIVE
  To investigate risk factors involved in the development of anterior cervical hematomas and determine any impact on patient outcomes.
  
  
  BACKGROUND
  Postoperative (PO) hematomas after anterior cervical spine surgery require urgent recognition and treatment to avoid catastrophic patient morbidity or death. Current studies of PO hematomas are limited.
  
  
  METHODS
  Cervical spine surgical procedures performed on adults by the senior author at a single academic institution from 1995 to 2012 were evaluated. Demographic data, surgical history, operative data, complications, and neck disability index (NDI) scores were recorded prospectively. Cases complicated by PO hematoma were reviewed, and time until hematoma development and surgical evacuation were determined. Patients who developed a hematoma (HT group) were compared with those that did not (no-HT group) to identify risk factors. NDI outcomes were compared at early (<11 mo) and late (>11 mo) time points.
  
  
  RESULTS
  There were 2375 anterior cervical spine surgical procedures performed with 17 occurrences (0.7%) of PO hematoma. In 11 patients (65%) the hematoma occurred within 24 hours PO, whereas 6 patients (35%) presented at an average of 6 days postoperatively. All underwent hematoma evacuation, with 2 patients (12%) requiring emergent cricothyroidotomy. Risk factors for hematoma were found to be (1) the presence of diffuse idiopathic skeletal hyperostosis (relative risk = 13.2, 95% confidence interval = 3.2-54.4), (2) presence of ossification of the posterior longitudinal ligament (relative risk = 6.8, 95% confidence interval = 2.3-20.6), (3) therapeutic heparin use (relative risk 148.8, 95% confidence interval = 91.3-242.5), (4) longer operative time, and (5) greater number of surgical levels. The occurrence of a PO hematoma was not found to have a significant impact on either early (HT: 30, no-HT: 28; P = 0.86) or late average NDI scores (HT: 28, no-HT 31; P = 0.76).
  
  
  CONCLUSIONS
  With fast recognition and treatment, no long-term detriment from PO anterior cervical hematoma was found. We identified risk factors to be (1) presence of diffuse idiopathic skeletal hyperostosis, (2) presence of ossification of the posterior longitudinal ligament, (3) therapeutic heparin use, (4) longer operative time, and (5) greater number of surgical levels.
  
  
  METHODS
  4.
authors.affiliation: From the Cervical Spine Service, Washington University, Department of Orthopedics, St. Louis, MO.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: O'Neill
authors.forename: Brian
authors.initials: B
authors.lastname: Neuman
authors.forename: Colleen
authors.initials: C
authors.lastname: Peters
authors.forename: K Daniel
authors.initials: KD
authors.lastname: Riew
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D006406:Hematoma / Q000209:etiology* / Q000601:surgery; D006801:Humans; D004057:Hyperostosis, Diffuse Idiopathic Skeletal / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D019637:Orthopedic Procedures / Q000009:adverse effects*; D017887:Ossification of Posterior Longitudinal Ligament / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult