title: Gross morphological changes of the spinal cord immediately after surgical decompression in a large animal model of traumatic spinal cord injury.
abstract: METHODS
  Quantitative in vivo ultrasound imaging study of spinal cord and dura morphology after acute experimental spinal cord injury (SCI) and decompression in a pig model.
  
  
  OBJECTIVE
  To study the morphological changes of the spinal cord and dura immediately after surgical decompression for acute SCI.
  
  
  BACKGROUND
  Surgical decompression for traumatic SCI is currently a topic of debate. After decompression, relief of bony impingement on the thecal sac and spinal cord can be confirmed intraoperatively. However, postoperative imaging often reveals that the cord has swollen to fill the subarachnoid space. Little is known about the extent and timing of this morphological response.
  
  
  METHODS
  Yucatan miniature pigs received sham surgery (N = 1) or a moderate (N = 6, 20 g, 2.3 m/s) or high (N = 6, 20 g, 4.7 m/s) severity weight-drop SCI followed by 8 hours of sustained compression (100 g) and 6 hours of postdecompression monitoring. Sagittal-plane ultrasound images were used to quantify spinal cord, dura, and subarachnoid space dimensions preinjury and once per hour after decompression.
  
  
  RESULTS
  Animals with a moderate SCI exhibited a residual cord deformation of up to 0.64 mm within 10 minutes of decompression, which tended to resolve during 6 hours because of tissue relaxation and swelling. For animals with high-severity SCIs, cord swelling was immediate and resulted in occlusion of the subarachnoid space within 10 minutes to 5 hours, whereas this occurred for only half of the moderate injury group.
  
  
  CONCLUSIONS
  Decompression of an acute SCI may result in residual cord deformation followed by gradual swelling or immediate swelling leading to subarachnoid occlusion. The response is dependent on initial injury severity. These observations may partly explain the lack of benefit of decompression in some patients and suggest a need to reduce cord swelling to optimize the clinical outcome after acute SCI.
authors.affiliation: Orthopaedic and Injury Biomechanics Laboratory, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada. claire.jones@alumni.ubc.ca
authors.forename: Claire F
authors.initials: CF
authors.lastname: Jones
authors.forename: Peter A
authors.initials: PA
authors.lastname: Cripton
authors.forename: Brian K
authors.initials: BK
authors.lastname: Kwon
mesh_terms: D000818:Animals; D019299:Decompression, Surgical / Q000379:methods*; D004195:Disease Models, Animal; D004388:Dura Mater / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D013116:Spinal Cord / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013119:Spinal Cord Injuries / Q000601:surgery*; D013346:Subarachnoid Space / Q000000981:diagnostic imaging / Q000473:pathology; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D015599:Trauma Severity Indices; D014463:Ultrasonography / Q000379:methods