The most typical presentation for Intervertebral Disc Disease (IVDD) is for dogs to present after a few days of them not quite being themselves or possible GI pain. Pet insurance data suggests lifetime prevalence of IVDD is 3.5% overall population, however, it is 2-62% of the lifetime prevalence of dachshunds with a mortality rate of 24%. Because of the high statistic in dachshunds, Assisi Animal Health participated in a clinical trial at, NC State, using the Assisi Loop for pain control.


To prognosticate in non-ambulatory animals presenting with spinal cord disease, assess voluntary motor function and pain perception. If an animal is a non-ambulatory, paraparetic or a paraplegic, one way to assess voluntary motor function of the pelvic limbs is to support the animal’s body weight with a hand under its pelvis. When the animal walks forward using its thoracic limbs, voluntary movements may be seen in the pelvic limbs. If there is minimal motor function, only hip flexion may be seen.


In a recumbent animal, touching the paws may elicit a reflex movement (withdrawal reflex), but it does not necessarily mean that the animal has voluntary movement. In animals lacking voluntary movements, assess pain perception. Evaluate superficial pain perception by pinching the toe web with a hemostat, and evaluate deep pain perception by pinching the toe (the periosteum). Again, withdrawing the limb is a withdrawal reflex; it does not mean the animal feels the pinch. A positive result in a pain perception test is the animal showing a conscious response to the stimulus, such as trying to bite, whining, or ceasing to pant, or an increase in heart and respiration rates.


Localization & grading. In grade one there is only pain without neuro deficits. In grade two ataxia and paraparesis are present. Grade three presents as non-ambulatory, paraparesis. Grade four is paraplegic and grade five is paraplegic without pain perception. In the NS State College Clinical Trial, a main focus was on Grade 5 with, again, the Assisi Loop used post surgery, to control pain and inflammation and accelerate healing.


Spinal radiographs may show evidence of disc degeneration and 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. CT can be used to diagnose mineralized disc herniation very effectively, but fails to identify soft tissue herniations without myelography. MRI is specific and sensitive, and can give prognostic information, but is more costly.


Calcification of the IVD is frequently observed in CD dogs. IVD calcification can be found at all spinal levels and can be seen as early as 5 months of age. Although the prevalence of disc calcification increases with age it appears to reach a steady state or maximum at 24–27 months of age.


Increased numbers of calcified discs in the spinal column is associated with the risk of developing IVD herniation at random spinal levels (not necessarily the calcified disc). Although calcification can affect IVD integrity and calcified discs can herniate, calcification occurs more often than IVD herniation. Partial or complete resolution of disc calcification has been reported and is common among CD dogs older than 3 years. This might be because increased tension and tearing of the AF may elicit an inflammatory response, with calcified material being removed by macrophage-like cells. Alternatively, pH changes within the IVD tissue may result in dissolution of calcified material.


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. Areas may become warmer or cooler, depending on whether the disruption in autonomic control causes an increase or decrease in blood flow. A recent study had success diagnosing TL IVDD in chondrodystrophic dogs.


Next week we will continue our discussion on Intervertebral Disc Disease and focus on treatment.