title: Pulmonary embolism diagnosed on computed tomography contrast angiography despite negative venous Doppler ultrasound after spinal surgery.
abstract: METHODS
  The focus of this study was on the frequency of negative initial/subsequent ultrasound (US) of the lower extremities but positive spinal computed tomography contrast angiography (CTA) diagnostic of pulmonary embolism (PE) among 75 patients undergoing cervical laminectomy/fusion and 165 patients having lumbar laminectomy/noninstrumented fusion.
  
  
  OBJECTIVE
  To determine the percentage/incidence of patients undergoing spinal surgery with negative US but with positive CTA.
  
  
  BACKGROUND
  The frequency of patients with negative US but with positive CTA after spinal surgery is not well documented.
  
  
  METHODS
  For 240 spinal surgery patients, postoperative prophylaxis against deep venous thrombosis consisted of alternating pneumatic compression stockings alone. The patients were routinely screened on postoperative days 1 to 2 for deep venous thrombosis using US. The incidence of initial/subsequent negative US and positive CTA diagnostic for PE in patients with mild/major symptoms was evaluated, in conjunction with the frequency of hypercoagulation syndromes.
  
  
  RESULTS
  Five (6.7%) patients undergoing cervical surgery and 6 patients (3.6%) undergoing lumbar surgery exhibited negative US but positive CTA on postoperative days 1 to 21. All the patients immediately received inferior vena cava filters (2 permanent and 9 retrievable). Five patients (45%) tested positive for hypercoagulation syndromes. Two patients were fully anticoagulated on postoperative days 3 and 21 with major symptoms attributed to saddle emboli; 1 had hypercoagulation syndrome. Anticoagulation was delayed for 6 to 12 weeks in 7 patients with milder symptoms, as magnetic resonance imaging scans showed residual seromas; 4 had hypercoagulation syndromes. Two elderly patients, at high risk for falls, without hypercoagulation syndromes were not anticoagulated.
  
  
  CONCLUSIONS
  The frequency of negative US of the lower extremities but with positive CTA for PE after 240 cervical/lumbar spinal procedures in patients with mild/major symptoms ranged from 3.6% to 6.7%; 5 of the 11 patients exhibited hypercoagulation syndromes. To avoid failure to diagnose PE after spinal surgery, one should have a "low threshold" (eg, based even on minor symptoms) for requesting the CTA.
authors.affiliation: Neurological Surgery, The Albert Einstein College of Medicine, Bronx, NY, USA. dch3@columbia.edu
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Epstein
authors.forename: Harry
authors.initials: H
authors.lastname: Staszewski
authors.forename: Michael
authors.initials: M
authors.lastname: Garrison
authors.forename: Man
authors.initials: M
authors.lastname: Hon
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011859:Radiography; D013131:Spine / Q000601:surgery*; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000000981:diagnostic imaging*