Sunday, October 2, 2011

Low back pain in a dog

The tail didn’t wag-couldn’t or wouldn’t, I wasn’t sure.  He stood there, tail drooping, looking at me with soft brown eyes that seemed to say, “please be gentle”.  He was big, a German Shepherd-cross breed dog that weighed close to 100 pounds.  His tail hadn’t swept the owner’s collectibles off the coffee table for several months.  Recently, she had spoken with me about the dog’s difficulty getting to stand on his hind feet.  I thought he might have cauda-equina compression syndrome, which would cause him pain on standing.  But now that he had come into the hospital it was clear his tail was also affected.   On rectal examination he showed pain when upward pressure was applied to the sacrum.  The spinal cord ends near the end of the lumbar spine and only nerves extend onward. The lumbosacral junction (where the spine attaches to the pelvis) had excessive flexibility and on radiographs there appeared to be new bone deposited in the spinal canal.  This was pressing the terminal spinal nerves against the roof of the spinal canal at the lumbosacral junction.  The dog could have been treated with an anti-inflammatory drug and pain would have been somewhat relieved but still he would suffer and eventually become disabled.
Instead, a dorsal laminectomy was performed.  His back muscles were separated over the lumbosacral junction and the tops of the last lumbar and first sacral vertebrae were carefully cut away with a rongeur to expose underlying nerves so that they were no longer crushed between the underlying new bone deposits and the top of the spinal canal.  The dog was placed in a recovery kennel.  When I checked on him at 10:00 that evening he still lay half asleep, but the next morning when I came in to visit him he jumped up, tail wagging gaily as he bounded out of the kennel.  His pain was gone and he can expect to live out a normal happy life.
Most dogs with cauda-equina compression syndrome require six to eight weeks to recover from surgery.  But the surgery is justified because in most cases it provides dogs prompt permanent relief from intractable back pain.