title: Longitudinal extension of myelomalacia by intramedullary and subdural hemorrhage in a canine model of spinal cord injury.
abstract: BACKGROUND
  In canine intervertebral disc (IVD) extrusion, a spontaneous animal model of spinal cord injury, hemorrhage is a consistent finding. In rodent models, hemorrhage might be involved in secondary tissue destruction by biochemical mechanisms.
  
  
  OBJECTIVE
  This study aimed to investigate a causal association between the extents of intramedullary, subdural and epidural hemorrhage and the severity of spinal cord damage following IVD extrusion in dogs.
  
  
  METHODS
  A retrospective study using histologic spinal cord sections from 83 dogs euthanized following IVD extrusion was carried out.
  
  
  METHODS
  The degree of hemorrhage (intramedullary, subdural, epidural), the degree of spinal cord damage in the epicenter (white and gray matter), and the longitudinal extent of myelomalacia were graded. Associations between the extent of hemorrhage and the degree of spinal cord damage were evaluated statistically.
  
  
  RESULTS
  Intramedullary and subdural hemorrhages were significantly associated with the degree of white (p<.001/ p=.004) and gray (both p<.001) matter damage, and with the longitudinal extension of myelomalacia (p<.001/p=.005). Intriguingly, accumulation of hemorrhagic cord debris inside or dorsal to a distended and ruptured central canal in segments distant to the epicenter of the lesion was observed exhibiting a wave-like pattern on longitudinal assessment. The occurrence of this debris accumulation was associated with high degrees of tissue destruction (all p<.001).
  
  
  CONCLUSIONS
  Tissue liquefaction and increased intramedullary pressure associated with hemorrhage are involved in the progression of spinal cord destruction in a canine model of spinal cord injury and ascending or descending myelomalacia. Functional and dynamic studies are needed to investigate this concept further.
authors.affiliation: Division of Neurological Science, Division of Clinical Neurology, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Länggassstrasse 128, Bern CH-3001, Switzerland. Electronic address: diana.henke@vetsuisse.unibe.ch.
authors.forename: Diana
authors.initials: D
authors.lastname: Henke
authors.affiliation: Division of Clinical Radiology, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Länggassstrasse 124, Bern CH-3001, Switzerland.
authors.forename: Daniela
authors.initials: D
authors.lastname: Gorgas
authors.affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 155, Liebefeld CH-3097, Switzerland.
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Doherr
authors.affiliation: Clinical Diagnostic Laboratory, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Länggassstrasse 124, Bern CH-3001, Switzerland.
authors.forename: Judith
authors.initials: J
authors.lastname: Howard
authors.affiliation: Division of Clinical Surgery, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Länggassstrasse 128, Bern CH-3001, Switzerland.
authors.forename: Franck
authors.initials: F
authors.lastname: Forterre
authors.affiliation: Division of Neurological Science, Division of Clinical Neurology, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Länggassstrasse 128, Bern CH-3001, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Vandevelde
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006408:Hematoma, Subdural / Q000150:complications / Q000473:pathology*; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000473:pathology*; D008297:Male; D066127:White Matter / Q000473:pathology
keywords: Ascending; Central canal; Descending; Intervertebral disc extrusion; Intramedullary pressure; Spinal trauma