A little background...
Dogs greater than 10 kg experience type 2 disc herniation more frequently than type 1 disc herniation. (Refresher: Type 1 = acute extrusion of the center of the disc; Type 2 = bulge of outer ring of the disc into the spinal canal.) An estimated 10-30% of the time large breed dogs have type 1, depending on the study.
How is a type 1 disc herniation different for a large breed dog?
The answer is rather obvious, but glossed over frequently. They are bigger! That means nursing care is harder, surgery takes longer and is more extensive, and as a result there can be a greater expense for some of our larger dogs.
Does the prognosis change for a medium to large breed dog?
Yes. Dr. Woelfel from NCSU recently published data from a cohort of dogs > 10 kg that had both acute disc herniation and extensive spinal cord hemorrhage.
(Spinal cord hemorrhage occurs infrequently for large and small breed dogs and was shown in a few studies to have a minimal effect on prognosis as a stand alone feature. Meaning, the prognosis was still mostly based on the presence or absence of deep pain and didn't depend on spinal cord hemorrhage identified on advanced imaging.)
Okay, back to big dogs with disc herniation and spinal cord hemorrhage. The NCSU study reported a worse prognosis, and a higher complication rate, compared to overall data for small breed and chondrodystrophic dogs.
The details in summary:
No deep pain before surgery, recovery about 38% (general population: 50%)
Deep pain present before surgery, recovery rate about 77% (general population:90-95%)
Complication rate was about 24% (general population: 10-15%)
Post Operative Complications Noted in the Referenced Study
Decubital ulcers
Pneumonia
Self-mutilation
Fever of unknown origin
MDR UTI
Sudden death
Progressive myelomalacia
What is the take home message?
When talking with an owner of a medium to large breed dog with acute onset paraplegia, I suggest emphasizing the need for intense at-home nursing care, possible complications (along with the higher incidence) and a realistic prognosis if the dog is diagnosed with a disc herniation on advanced imaging. Remember that other differential diagnoses can cause acute onset paraplegia! Please do not interpret this paragraph as a call for euthanasia for large breed dogs with acute paraplegia. A 38% recovery rate is not zero! But a honest, open, vet-to-client discussion is the best way to achieve an informed decision for the client.
Not sure if you are interpreting the neurologic examination appropriately? Not sure if you are doing the neurologic examination properly? Please reach out! I am happy to work with you to help guide your clients in a compassionate and informed way.
Happy Easter to those that celebrated last weekend. We welcomed spring with big smiles around my house this weekend!
Reference: Woelfel, CW, Robertson, JB, Mariani, CL, Muñana, KR, Early, PJ, Olby, NJ. Outcomes and prognostic indicators in 59 paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion. Veterinary Surgery. 2021; 50: 527– 536. https://doi.org/10.1111/vsu.13592