title: Clinical and pathological analysis of epidural inflammation in intervertebral disk extrusion in dogs.
abstract: BACKGROUND
  Little is known about the pathologic changes in the epidural space after intervertebral disk (IVD) extrusion in the dog.
  
  
  OBJECTIVE
  To analyze the pathology of the epidural inflammatory response, and to search for correlations between this process and clinical findings.
  
  
  METHODS
  Clinical data from 105 chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs with IVD extrusion were recorded. Epidural material from these dogs was examined histopathologically and immunohistochemically. Using statistical analysis, we searched for correlations between severity of epidural inflammation and various clinical and pathologic variables.
  
  
  RESULTS
  Most dogs exhibited an epidural inflammatory response, ranging from acute invasion of neutrophils to formation of chronic granulation tissue. The mononuclear inflammatory infiltrates consisted mostly of monocytes and macrophages and only few T and B cells. Surprisingly, chronic inflammatory patterns also were found in animals with an acute clinical history. Severity of the epidural inflammation correlated with degree of the epidural hemorrhage and nucleus pulposus calcification (P = .003 and .040), but not with age, chondrodystrophic phenotype, neurologic grade, back pain, pretreatment, or duration. The degree of inflammation was statistically (P = .021) inversely correlated with the ability to regain ambulation.
  
  
  CONCLUSIONS
  Epidural inflammation occurs in the majority of dogs with IVD extrusion and may develop long before the onset of clinical signs. Presence of calcified IVD material and hemorrhage in the epidural space may be the triggers of this lesion rather than an adaptive immune response to the nucleus pulposus as suggested in previous studies. Because epidural inflammation may affect outcome, further research is warranted.
authors: Division of Neurological Sciences, University of Bern, Bern, Switzerland. angela.fadda@vetsuisse.unibe.ch
authors: A
authors: A
authors: Fadda
authors: A
authors: A
authors: Oevermann
authors: M
authors: M
authors: Vandevelde
authors: M G
authors: MG
authors: Doherr
authors: F
authors: F
authors: Forterre
authors: D
authors: D
authors: Henke
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D004388:Dura Mater / Q000473:pathology*; D005260:Female; D007150:Immunohistochemistry; D007249:Inflammation / Q000209:etiology / Q000662:veterinary*; D007405:Intervertebral Disc Displacement / Q000473:pathology / Q000662:veterinary*; D008297:Male
keywords: Immune response; Intervertebral disk herniation; Nucleus pulposus