The first report of Intervertebral disc (IVD) disease in a dog was published in 1881 and involved a Dachshund with acute onset of hind limb paralysis. It would take over 40 years for the condition to be correctly described in veterinary literature. During the 1950’s, studies of IVD degeneration in dogs were performed by the Swedish veterinarians Hansen and Olsson. This led to first clear description of intervertebral disc degeneration and herniation and explained the distinction between chondrodystrophic (CD) and non-chondrodystrophic (NCD) breeds with regards to this process. A new (2012) scheme for grading histopathological changes was recently proposed by Bergknut et al., which not only evaluates the cellular and structural changes in the four zones also considers changes in tissues or structures adjacent to the IVD.

Degeneration of a Healthy Intervertebral Disc

The healthy IVD is composed of four distinct components: Nucleus Pulposus, Annulus Fibrosus, End Plates (arrows), and Transition Zone. During motion, the canine IVD can be subjected to several motions/loading conditions: axial compression, shear, tension, bending, and torsion. The components work as a functional unit to resist these loads. Unfortunately, IVD degeneration is an imminent effect of aging in dogs.

Types of IVDD

Type I IVDD is common in small breed, CD dogs such as Dachshund, French Bulldog, Pekingese, Beagle, Basset Hound, and Shih Tzu. Part of the IVD undergoes changes (decreased water content and subsequent mineralization) causing altered disc biomechanics. Continued abnormal forces cause the dorsal portion to weaken and the mineralized center is acutely extruded into the vertebral canal, causing a sudden onset of painful neurologic dysfunction.

Type II IVDD typically occurs in NCD, large breed dogs. With this type of disc degeneration, there are fibrous changes to the disc and concurrent degeneration. This degenerative process leads to central bulging with gradual dorsal protrusion into the vertebral canal. Clinical signs are most commonly observed in geriatric animals. Pain and neurologic dysfunction in these cases results from chronic compression of the spinal cord and nerve roots.

Type III IVDD is now re-classified as acute non-compressive nucleus pulposus extrusion (ANNPE) where the disc has shot through the cord. These are also called missile disc or traumatic disc.

Calcification and Other Complications

Calcification, a process associated with IVD, is frequently observed in CD dogs, but rarely in NCD dogs. Calcification can be found at all spinal levels and can be seen as early as five months of age. An increase in the total number of calcified discs is associated with the risk of developing herniation, but at random spinal levels.

Recently, a group at UC Davis reported the identification of a fibroblast growth factor 4 (FGF4) retrogene insertion on chromosome 12 as responsible for chondrodystrophy and increased risk of IVDD; this unfortunately confers a 50-fold risk of having IVDD.

Diagnosis of IVDD

To help reach a diagnosis and prognosis in non-ambulatory animals, voluntary motor function or pain perception must be assessed. Superficial pain perception is evaluated by pinching the toe web with a hemostat, and deep pain perception is evaluated by pinching the toe (periosteum). A positive result in a pain perception test occurs if the animal shows a conscious response to the stimulus, such as trying to bite, whining, or ceasing to pant, or an increase in heart and respiration rates. Grade I is spinal pain only, Grade II is ataxia and weakness, Grade III is non-ambulatory paraparesis, Grade IV is paralysis, and Grade V is paralysis without pain perception.

Spinal radiographs may show evidence of disc degeneration (nuclear calcification) and may show signs of herniation (narrowed disc space, opacification of the intervertebral foramen), but a definitive diagnosis is only established with advanced imaging using magnetic resonance imaging (MRI), computed tomography (CT), or myelography.

The Cutaneous Trunci Muscle Reflex (CTMR) is a relatively complex reflex elicited by applying a stimulus to the skin which stimulates the superficial spinal nerves that innervate a particular region of the dermis and elicits a motor response; the response is a skin twitch. This test can be used to help localize a spinal cord lesion.  If a response is absent, the lesion is 1-2 vertebra cranial to this level as the sensory nerves travel slightly cranially before synapsing.

Medical Infrared Imaging (MII) or thermography is a noninvasive imaging modality that measures and graphically displays skin temperature patterns. Temperature of the skin dermatome is directly influenced by its perfusion. It is under control of the sympathetic nervous system, so any process that disrupts it will alter perfusion and thus change the surface temperature and thermographic pattern of that region. A recent study had success diagnosing TL IVDD in chondrodystrophic dogs.


Grades I and II IVDD have 80-90% success rate when treated conservatively. Grade III has >70% success rate treated conservatively. Grades I, II, and III have > 90% if treated surgically. Grade IV has about 50% success rate with conservative treatment and about 90% success treated surgically. Grade V patients have about a 5% success rate with either treatment.


The aim of conservative management is to avoid further deterioration of the patient due to herniation of additional disc material, while allowing the patient time to recover from the spinal cord injury. The goal of surgery is the decompress the spinal cord and reduce the risk of recurrence.  Surgery is recommended for all non-ambulatory dogs, Grades III – V disease, and vital for Grade V disease. Post-op management is the same as with conservative treatment.

If they can’t walk but can feel, surgery is best within 24 hours. If they are paraplegic without sensation,  studies demonstrate that >50% of dogs recover the ability to ambulate within three months of decompressive surgery. Being surgically delayed increases the risk of clinically meaningful deterioration, as well as a higher incidence of progressive myelomalacia (pmm). Dogs that cut while still ambulatory versus delayed have less fecal and urinary incontinence.

Steroids and Anti-Inflammatories

Perhaps the most discussed issue is whether corticosteroids (how much and which one) should be used for acute IVDH. Anti-inflammatory doses of steroids are used to treat pain and inflammation associated with disc herniation. However, many studies have shown that using steroids can increase adverse effects without increasing the neurological outcome. Unfortunately, when gastric mucosal lesions of IVDD patients receiving omeprazole and misoprostol for steroid protection were examined, there was no demonstrated protective effect. One retrospective study did show low doses of steroids reduced the risk of PMM.

Non-steroidal anti-inflammatories (NSAIDS) have both central and peripheral effects. Their anti-prostaglandin characteristics make them appropriate for minimizing the peripheral sensitization of nociceptors and their inhibition of cyclooxygenase (COX) within the spinal cord give them centrally acting analgesic attributes as well. Opioids play a significant role in action on descending nociceptive or sensory neuron modulatory pathways. Muscle relaxants (e.g. diazepam or methocarbamol) are helpful when the pain is due to muscle spasms. NMDA receptor antagonists (i.e. amantadine and ketamine) reduce central sensitization and hypersensitivity. The anticonvulsant analgesic, Gabapentin, is well-tolerated and can be helpful in the multimodal pain management plan.

Therapeutic Treatments for IVDD

1) Passive Range of Motion (PROM) – Movement of a limb performed without a muscle contraction (by the practitioner). PROM helps prevent joint contracture and soft tissue shortening, maintains mobility between soft tissue layers, enhances blood and lymph flow, and improves synovial fluid production and diffusion.

2) Cryotherapy – controls pain and inflammation. Compression can increase the depth of penetration. When used in the acute post op or post injury period, cryotherapy is best used in the first 72 hours. Monitor the skin for signs of irritation and discomfort, especially in animals with decreased sensation.

3) Thermal Heat Therapy – decreases joint stiffness, relieves spasms, reduces swelling, and increases circulation. Moist heat penetrates more deeply than dry heat. Heat should not be used if there is swelling or edema in the joint or limb. It is usually safe to add heat 72 hours after an injury.

4) Laser Therapy (photobiostimulation) – can be helpful in the early stages of treatment to control pain and expedite healing. Results include analgesia, reduction in inflammation, acceleration in tissue healing, increased cellular metabolic activity, improved nerve function, and stimulation of acupuncture points. Tissue or wound healing occurs through increased leukocyte production, early cell generation, increased tensile strength, increased vascular regeneration, and increased fibroblast production.

5) Electrical modalities such as transcutaneous electrical nerve stimulation (TENS) – provide pain relief by stimulating cutaneous pain fibers. TENS is effective through a gate-control or counter-irritant mechanism:  a large number of benign stimuli compete with the painful stimuli. Neuromuscular electrical nerve stimulation (NMES) is used for muscle strengthening. NMES has many benefits in IVDD patients as it may be used to strengthen specific muscles in OA patients with neurological deficits and disuse atrophy.

6) The Land Treadmill (LTM) – can be used to strengthen, re-educate neurological deficits, and build endurance. In and underwater treadmill (UWTM), the buoyancy provides support so a very weak animal can stand with the water’s support. Water depth can be adjusted to change the effect of buoyancy on the more efficient workout.  The warm water increases circulation, alleviates pain, and causes peripheral vasodilation, which increases cardiovascular demand.   

7) Massage – can increase arterial, venous, and lymphatic flow and can break down tissue adhesions. Tissue manipulation can clear edema and muscles spasms, relieving soreness.

8) Pulsed Electromagnetic Field Therapy (PEMF)  PEMF an active electromagnetic waveform delivered by antenna. PEMF technologies are differentiated by parameters of waveforms they emit such as antenna size and duration and frequency of the application. These combined determine the strength and efficacy. Targeted PEMF waveforms operate at about 1000’s less power than cell phones so they do not cause heat or membrane depolarization. Human and veterinary research has shown pain control and healing with approximately 50% less need for concurrent opioid use. Other recent veterinary findings include better proprioceptive placement and decreased glial fibrillary acidic protein (marker of spinal cord injury).

9) Acupuncturewhen an acupuncture needle is inserted into and rotated, collagen and elastic fibers wind and tighten around the needle, causing a mechanical coupling between the tissues and the needle. The deformation of the fibrin matrix pulls on the nerve endings and fibroblasts, and interacts on muscle spindles. A series of cellular responses follow causing neuromodulation and decrease in pain signal transmission.

Therapeutic Exercises for IVDD

Therapeutic exercises should focus on balance, proprioception, and strengthening. Standing exercises can begin as soon as treatment begins. Support can be given using slings, a physioroll, a lift system, or wheelchair/cart.  With the patient in a supported standing position, gentle pressure can be applied to the dorsal aspect of the pelvis.

Isometric exercises, a type of strength training where the joint angle and length do not change during contraction, are excellent in early recovery. Examples are three-legged and two-legged standing (alternating any and all four limbs).

Core exercises are important to support the spine. Examples of core strengthening exercises include contralateral limb standing or plank.  Plank can be done by having the animal stand with its front limb higher than the hind. A Bosu can be used and the nubbed surface helps provide a proprioceptive feedback to the paws. Cavaletti rails are an excellent exercise to increased proprioceptive awareness, as it encourages the patient to think about an enhanced footstep. If the animal’s foot hits a rail, its body is reminded of where its limb is in space.

It is always important to keep a detailed record of the exercise sessions, including how the animal performs the exercises, along with the other variables. A home exercise program (HEP) should be assigned. Pay attention to the home environment (slippery or carpeted floors, stairs or no, etc.).  Send home no more than three exercises to be done five days a week with two non-consecutive days off.


For Types I and II IVDD, the neuroplasticity window is 9-12 months. Borrowing from human research, re-learning to move one joint takes over 1,300 repetitions of exercise and in an average therapy session one does 25-35 – so don’t give up!