Kara C. Knight DVM, Diplomate ACVIM (Neurology)
Degenerative disk disease is common in dogs, and occurs less frequently in cats. There are two types of disk degeneration, chondroid and fibrinoid, which lead to two distinct types of disk disease (Hansen Type I and Hansen Type II). Hansen Type I disk herniation occurs when the annulus fibrosus is fissured and the degraded nucleus pulposus extrudes into the vertebral canal. This is most frequently seen in chondrodystrophic breeds. Hansen Type II disk protrusions occur when the intact annulus fibrosus thickens and protrudes dorsally into the vertebral canal.
Referral is recommended when:
- Patient has spinal pain of unknown etiology
- Patient has any neurologic deficits (weakness, ataxia, incontinence)
– Non-surgical Management:
Recommended in cases of first time pain and very mild and static neurologic deficits.
- Analgesics and anti-inflammatories
– Don’t use steroids and NSAIDs together
– Use only anti inflammatory doses of corticosteroids
– High doses of injectable corticosteroids are controversial & may do more harm than good.
- Very strict crate rest for 4-6 weeks,
– Rest is vital. It is unacceptable to administer analgesics without resting the dog
– Forced rest minimizes further disk herniation and decreases inflammation.
If the patient fails to improve or worsens during the period of confinement, surgical management should be pursued.
- Recommended for recurrent pain, moderate to severe neurologic deficits (even if ambulatory), and patients that are deteriorating quickly.
- CT scan, myelogram, or MRI are required to determine etiology and exact site.
- Surgical procedures: hemilaminectomy, dorsal laminectomy, ventral slot. Prognosis with surgery in dogs with Type I disk extrusion and intact pain sensation: 80-95% for functional recovery.
Neurologic examination questions to be answered:
- Is the patient ambulatory on its own?
- If not ambulatory, does it have voluntary motor function?
- If there is no motor function, does the dog have superficial pain sensation?
– sharp, well-localized pain originating from the skin
– look for behavioral response to a firm skin pinch
- If there is no superficial pain sensation, does the dog have deep pain sensation?
– burning, aching, poorly localized pain from skin and deeper tissues (e.g., periosteum) look for a behavioral response to a firm hemostat pinch over a toenail bed or digit.
– Further reading: Dewey CW – A Practical Guide to Canine and Feline Neurology. 2008