OSU vets pioneer disk surgery for dogs

Thursday, June 7, 2007

The veterinary hospital at Oklahoma State University’s Center for Veterinary Health Sciences offers percutaneous laser disk ablation surgery for canines. It is the sole provider worldwide of the treatment option for dogs.  

The first investigation was conducted at OSU’s Veterinary Center by Drs. George Henry and Kenneth Bartels' initial studies focused on the effects of laser treatment on tissues similar to the intervertebral disk material. The research's scope was to discover the effects of laser energy on intervertebral disk material and how the denatured disk might be kept from extruding or herniating in the future, causing spinal cord injury. In late 1993, the procedure was used on clinically affected dogs.

More than 300 cases have been treated at OSU’s Veterinary Medical Teaching Hospital with excellent results. The procedure is designed to prevent the recurrence of disk herniation with subsequent spinal cord damage. The success rate is based on the recurrence rate in the treated dogs.  

“Our success rate is 96.6%,” Dr. Robert Bahr said. “That means that out of all the dogs treated since the project began in 1993 (some 325 dogs total), only nine dogs (3.4%) have had repeat disk herniations.”

The disease can be treated with “sharp” surgical procedures as well. However, the most commonly performed surgical procedure, disk fenestration, is more complicated and painful for the animal. Fenestration calls for the veterinarian to surgically open the dog’s back and isolate the intervertebral disks by dissecting the muscle away from the vertebrae. Then, using a surgical instrument shaped like a hook, the disk material is scraped out of its anatomic location, which prevents it from herniating in the future. This is tremendously painful for the dog because the back muscles are cut, usually bluntly, to lessen bleeding, which causes a great deal of post-operative pain as well as two to three weeks of post-surgery rehabilitation.

The laser surgery is done by placing needles through the skin into the centers of seven different disk locations while the dog is under general anesthesia. The locations are based on the most common sites of thoracolumbar intervertebral disk disease as described in the veterinary literature. An x-ray is taken to ensure that each needle tip is precisely in the center of each treated disk. Then, a Holmium: YAG laser fiber is put through the needle and into the disk's center, turning the laser energy on. This laser surgical treatment liquefies the disk material and scar tissue forms, which prevents the disk from herniating and injuring the spinal cord in the future.

If left untreated, diseased disks can extrude or herniate from their normal location and put pressure on the spinal cord. This could eventually lead to back pain and other physical limitations such as permanent abnormal gait, lameness, loss of bowel and bladder control that can reduce a pet’s quality of life or even permanent paralysis. The laser disk ablation procedure can prevent such ailments.

Of the various treatments available, laser disk ablation surgery, an interventional radiologic procedure, results in a lower recurrence rate than the other methods of prevention that have been tried in the past. The procedure is indicated for dogs experiencing only “back pain.” It is not recommended for dogs with signs of spinal compression.

Certain breeds of dogs are more likely to require some form of treatment to prevent future recurrence of degenerative disk disease with disk herniation. These include Dachshund, Shih Tzu, Lhasa Apso, Pomeranian, Miniature Schnauzer, Miniature and Toy Poodle, Yorkshire Terrier and Cocker Spaniel, among other small breeds of dogs. Large-breed dogs can also be affected, but the disease is slower to develop and has a somewhat different pathophysiology. In small dogs, it is more acute and more likely to cause permanent paralysis. The disease may cause less severe spinal cord damage in larger dogs and is less likely to recur.  

According to Bahr, the Veterinary Teaching Hospital at the CVHS treats two to five disk cases each week and sees patients from Oklahoma and the surrounding states of the south-central and midwest to the east coast of the United States. OSU veterinarians have also used the procedure to treat patients from as far away as Idaho and Oregon. The procedure costs approximately $1,500.