Recovery of Ambulation in Medically Managed Thoracolumbar Disc Extrusions in Non-Ambulatory Small Dogs

Acute thoracolumbar intervertebral disc extrusion is a common reason for dogs to present to referral practices the consequences of which range along a spectrum from spinal hyperaesthesia without concurrent neurological deficits to paraplegia with absent pelvic limb and tail deep nociception, something usually termed “deep pain negative”. Although we have been aware of this type of myelopathy as far back as the 1890s, there remains debate regarding the appropriate treatment for affected dogs. Currently available treatments are categorised as either surgical or conservative but to date, these treatment options have never been directly compared in a randomised controlled trial. Furthermore, most studies reporting outcomes following conservative management are either retrospective or small prospective series, leaving limited available evidence to facilitate the use of conservative management in clinical practice. This has led to a consensus that surgical management is superior to conservative management and that it may be the sole route to recovery for non-ambulatory dogs despite several reports of recovery following conservative management. Whilst the prognosis for recovery of function following surgery is undeniably favourable this is not available for many dogs due to financial or geographic restrictions and so it is possible that the consensus is leading to dogs being euthanised who could have been recovered conservatively. To address the paucity of evidence for conservative management I recruited non-ambulatory dogs with thoracolumbar intervertebral disc extrusions and managed them conservatively over a period of 12 weeks. By doing this I was able to demonstrate that many dogs managed conservatively can be recovered medically including many of those who were deep pain negative on presentation confirming that this is a valid alternative to euthanasia. I also undertook morphometric analysis of MR images obtained at the beginning and end of the study period which documented complete regression of some extruded discs as well as some which remained relatively unchanged. I was also able to show that not only can recovery occur in the face of substantial compression but also that for many dogs, recovery is independent of the removal of compressive material. Lastly, through morphometric MRI analysis I documented the importance of the contusive injury and its potential significance in deep pain negative dogs which may help guide future research.

Kennel Club Charitable Trust Petsavers Debs Foundation Alice Noakes Trust Dachsund Rescue UK