Lower back arthritis in dogs and cats
Most lower back arthritis in dogs and cats is a neurological disorder involving the joint between the last lumbar vertebrae and the sacrum. This is called degenerative lumbosacral disease. The lumbosacral area is a complex joint that surrounds the spinal cord within the pelvic region, provides mobility to the lower back and attaches the vertebral column to the pelvis.
Degeneration of the intervertebral disc leads to protrusion of the disc into the spinal canal. This causes pain. There can also be an instability of the vertebrae of the lumbosacral joint, which can cause a partial dislocation. The end result of these degenerative changes is compression of the spinal nerves that go to the hind legs, rear end, tail, bladder, colon and rectum. Older to middle-age, large-breed dogs are most commonly affected, especially German shepherds. Cats are also affected by lumbosacral arthritis.
Pain over the lumbosacral region as the most common sign. Other signs include a reluctance to jump, climb stairs or arise from a lying position. Hind-limb weakness and urinary and fecal incontinence may also occur. The degree of pain and neurological signs vary with the severity of the compression of the spinal cord.
Clinical signs are not necessarily very specific to degenerative lumbosacral disease. This problem can be mimicked by other disease, such as vertebral malformation, infection, trauma and cancer. X-rays are often performed—they help to rule out infection, cancers and vertebral malformation. MRIs provide the best detailed evaluation of the spinal nerves, intervertebral disc and vertebrae in this area.
Treatment options involved conservative and surgical therapies. Conservative therapy is often pursued if pain is the only clinical sign. Surgical therapy is often used in dogs with more severe neurological signs such as hind limb paresis or paralysis. Conservative therapy consists of exercise restriction, anti-inflammatory drugs and medications to relieve pain. When conservative therapy is unsuccessful, surgery is done. The goal of surgery is to eliminate compression of the spinal nerves.
Prognosis with conservative therapy depends upon the severity of the spinal cord and spinal nerve compressions. Conservative therapy is usually successful in 70 percent of all cases. If surgery is necessary, recovery can take up to three to four months. Even then, a full return to rear leg usefulness is not always the case. Dogs with pain as the sole clinical sign typically respond well to conservative therapy. The outcome for dogs with severe neurological problems is less predictable.