Cauda Equina Syndrome

This past summer Trapper started showing subtle signs of discomfort. At first it wasn't clear that he was in pain, as the only behavior out of the ordinary was a crawling action or "sneaking" preceding the first time he rose from the floor in the morning.  Bob stumbled upon this activity almost by accident.  Normally Trapper would retreat to the basement during the evening to take advantage of the cool concrete floor.  Upon hearing Bob get up for his morning run Trapper would come upstairs to greet Bob and eagerly join in the jog. After a while Bob noticed that Trapper wouldn't come upstairs immediately. Thinking maybe Trapper was getting hard of hearing (due to his age - seven years) Bob went to investigate.  When Bob entered the basement room where Trapper was he thought it was odd that Trapper didn't rise to greet him. He just continued to lay on the floor. This went on for a period of days until Bob eventually stuck around long enough to actually watch Trapper rise from the floor.  He was baffled when he noticed that Trapper would crawl along on his belly for some distance, and then slowly rise to a standing position as he continued walking.  The dog didn't really seem to be in pain until one day he rose and then immediately got down on his belly again, this time huffing and puffing.

Bob took him to his veterinarian, Dr. Bob Sept, who ran a series of tests and took several x-rays.  Dr. Sept was shocked to see in the x-rays how damaged Trapper's spine was at the L7-S1 intervertebral disk.  He sent Bob to Dr. Mike Edwards, a veterinary surgeon in Anchorage for a consultation.  After the consultation it was agreed that the best way to proceed was to first have Trapper examined with Magnetic Resonance Imaging (MRI) in order to determine the treatment options.  Unfortunately, the nearest veterinary hospital with a dedicated MRI machine is the Veterinary Teaching Hospital on the campus of the Washington State University, at Pullman.

Trapper was examined by WSU resident neurosurgeon Dr. Sean Sanders and the professor of neurosurgery, Dr. Rodney Bagley.  They determined that Trapper was exhibiting signs of Cauda Equina Syndrome due to Intervertebral Disk Disease and Lumbo-Sacral Instability.  They decided that Trapper needed to have a dorsal laminectomy and would benefit from fusing the L7 vertebra to the S1 vertebra due to instability in the spine.

Trapper went under the knife on September 20, 2000.  The doctors, working as a team, performed the laminectomy and placed two screws in his back.

Trapper is back home and on the mend.  His staples were removed on October 2, 2000.  The bone graft performed as part of the fusion won't be solid until about six to eight weeks post-surgery.  During this time he has to be kept quiet to prevent damage to the repair. Once five months have passed Trapper should be able to resume his vocation, retrieving ducks and geese.

The photos below are from the procedure done to Trapper.

This is a Magnetic Resonance Image taken of Trapper's back prior to the operation. This image shows a longitudinal section down the center of his back with Trapper's legs in a "normal" or standing position. Note the pinching of the spinal nerves (#1). The objects identified by the #2s are healthy spinal disks.  The disk at the L7-S1 junction is collapsed and has lost its fluid center and therefore does not appear in the MRI.  In its place can be seen a spondylosis, or bulbous arthritic bridging between the L7 and S1 vertebrae (#3).  This is the result of the body's attempt to stabilize the intervertebral disk space.

This image, also taken prior to the operation, shows how the impingement of the spinal nerves was relieved when Trapper's legs were moved forward (#4). This posture-dependent impingement is evidence of a continuing spinal instability.

Here are lateral radiographs (X-rays) of Trapper's spine both before and surgery.  The disk space that was lost in between L7 and S1 was restored with a lamina spreader (noted by the two arrows in the bottom photo). Screws were placed retaining the spacing between the two vertebra.  Ground up bone from Trapper was packed in cleaned out spaces between L7 and S1 in an effort to allow the body to fuse the two bones into one strong solid mass.

These radiographs, taken from above, also show the before and after condition of Trapper's spine. The staples used to close Trapper's incision are visible in the X-ray.

Trapper is shown in the skilled hands of Dr. Sean Sanders, D.V.M., College of Veterinary Medicine, Washington State University, Resident, Neurology, Neurosurgery. The photo on the right shows Trapper's incision as it appeared five days after surgery.

October 11 Update: It has been three weeks since the operation. In just the last day or two the improvement in his attitude and movement has been dramatic. Up to this point he was moving like an old dog. Now the challenge will be to keep him quiet until the bone graft has a chance to finish healing. His hair is growing back and his surgical incision is disappearing. We will keep our fingers crossed that he makes it through the next five weeks or so without any setbacks.

October 29 Update: With almost six weeks behind us, Trapper continues to improve. His "bad" days are becoming few and far between. His hair is about half grown back. He moves well, getting up from the floor quickly and easily without any apparent discomfort.  He is eager to get back into his old routine. In fact Trapper is now jogging four miles a day with Bob (at an even, slow pace on level ground). Since his surgery, he has lost a noticeable amount of muscle mass from his hind legs, but we suspect that he will regain much of that between now and next duck season.

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