title: Postoperative spinal epidural hematoma (SEH): incidence, risk factors, onset, and management.
abstract: BACKGROUND
  Spinal epidural hematoma (SEH) is a rare, yet potentially devastating complication of spinal surgery. There is limited evidence available regarding the risk factors and timing for development of symptomatic SEH after spinal surgery.
  
  
  OBJECTIVE
  To assess the incidence, risk factors, time of the onset, and effect of early evacuation of symptomatic SEH after spinal surgery.
  
  
  METHODS
  Multicenter case control study.
  
  
  METHODS
  All patients who underwent open spinal surgery between October 1, 1999, and September 30, 2006, at the National Hospital For Neurology and Neurosurgery (NHNN) and the Wellington Hospital (WH) were reviewed.
  
  
  METHODS
  Frankel grade.
  
  
  METHODS
  Patients who developed SEH and underwent evacuation of the hematoma were identified. Two controls per case were selected. Each control had undergone a procedure with similar complexity, at the same section of the spine, at the same hospital, and under the same surgeon within 6 months of the initial operation.
  
  
  RESULTS
  A total of 4,568 open spinal operations were performed at NHNN and WH. After spinal surgery, 0.22% of patients developed symptomatic SEH. Alcohol greater than 10 units a week (p=.031), previous spinal surgery (p=.007), and multilevel procedures (p=.002) were shown to be risk factors. Initial symptoms of SEH presented after a median time of 2.7 hours (interquartile range [IQR], 1.1-126.1). Patients who had evacuation surgery within 6 hours of the onset of initial symptoms improved a median of 2 (IQR, 1.0-3.0) Frankel grades, and those who had surgery more than 6 hours after the onset of symptoms improved 1.0 (IQR, 0.0-1.5) Frankel grade, p=.379.
  
  
  CONCLUSIONS
  Symptomatic postoperative SEH is rare, occurring in 0.22% of cases. Alcohol consumption greater than 10 units a week, multilevel procedure, and previous spinal surgery were identified as risk factors for developing SEH. Spinal epidural hematoma often presents early in the postoperative period, highlighting the importance of close patient monitoring within the first 4 hours after surgery. This study suggests that earlier surgical intervention may result in greater neurological recovery.
authors.affiliation: Spinal Injury Unit, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, United Kingdom. amir.r.amiri@googlemail.com
authors.forename: Amir R
authors.initials: AR
authors.lastname: Amiri
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Fouyas
authors.forename: Suzie
authors.initials: S
authors.lastname: Cro
authors.forename: Adrian T H
authors.initials: AT
authors.lastname: Casey
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D046748:Hematoma, Epidural, Spinal / Q000453:epidemiology* / Q000209:etiology* / Q000601:surgery; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects*; D011184:Postoperative Period; D012307:Risk Factors; D013131:Spine / Q000601:surgery*; D016896:Treatment Outcome