The spine of our pets is made of numerous small bones called vertebrae. These are the bones that contain and protect the fragile spinal cord. The vertebrae form multiple joints that allow for the flexibility of the back. These joints are called intervertebral disks.
The disks serve as cushions between the vertebral bodies. They consist of a fibrous outer shell (the annulus fibrosus) and a jelly-like interior (the nucleus pulposus). Ligaments run below and above the disks. These ligaments are called the dorsal (above) and ventral (below) longitudinal ligaments.
Intervertebral disk disease is a process that can cause the disk to press painfully against the spinal cord itself.
There are two types of intervertebral disk disease: Hansen Type I Disk Disease and Hansen Type II Disk Disease. In Type I, the jelly center of the disc becomes hardened. A normal movement by the patient can cause the rock-like disk material to shoot out and press on the spinal column.
Type II Disk Disease is a slower degenerative process. In this scenario, the outer shell (annulus fibrosus) collapses and protrudes upward creating a more chronic problem with pain and spinal cord compression.
Dogs that develop either of these conditions typically present with a hunched posture, shaking, pain when touched, and an unwillingness to move. With more severe cases, dogs can become paralyzed in affected limbs.
The treatment protocol for this disease process depends on the severity and duration of the disease process. This may be something where we as general practitioners recommend a transfer to a specialist to evaluate for surgery, in particular a veterinary neurologist.
Typically we are able to localize the area of spinal pain on physical examination. Any of the disks in the spinal column can degenerate, from the neck to the pelvis. Intervertebral disks cannot be seen directly on an xray; they can only be visualized on more advanced imaging, such as an MRI. It is important to take an xray in these cases to rule out other diseases that can cause the same symptoms, such as a spinal infection or vertebral cancer.
After isolating the area of discomfort, the doctors at Mt. Carmel Animal Hospital place these pets on a program of strict rest and restriction. They are not allowed to run, jump or play for approximately four weeks, to allow the spinal inflammation to decrease and scar tissue to form over the affected disk area. In the meantime, we place them on various pain medications, muscle relaxers, and anti-inflammatories to keep them comfortable and allow the body to heal. Additionally, anti-inflammatory laser treatment can provide relief to sore muscles and promote blood flow to the affected area of the spinal cord.