Preliminary data of this paper were previously presented as a poster presentation at the 25th ECVN/ESVN Annual Symposium in Ghent, Belgium, September 13–15, 2012
Clinical and Pathological Analysis of Epidural Inflammation in Intervertebral Disk Extrusion in Dogs
Article first published online: 6 MAY 2013
Copyright © 2013 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 27, Issue 4, pages 924–934, July/August 2013
How to Cite
Fadda, A., Oevermann, A., Vandevelde, M., Doherr, M.G., Forterre, F. and Henke, D. (2013), Clinical and Pathological Analysis of Epidural Inflammation in Intervertebral Disk Extrusion in Dogs. Journal of Veterinary Internal Medicine, 27: 924–934. doi: 10.1111/jvim.12095
- Issue published online: 15 JUL 2013
- Article first published online: 6 MAY 2013
- Manuscript Accepted: 14 MAR 2013
- Manuscript Revised: 11 FEB 2013
- Manuscript Received: 7 NOV 2012
- Immune response;
- Intervertebral disk herniation;
- Nucleus pulposus
Little is known about the pathologic changes in the epidural space after intervertebral disk (IVD) extrusion in the dog.
To analyze the pathology of the epidural inflammatory response, and to search for correlations between this process and clinical findings.
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.
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.
Conclusion and Clinical Importance
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.