Slew's Successful Surgery
March 6, 2002 - The Horse
by Kimberly S. Herbert

Seattle Slew, the only living winner of Thoroughbred racing's Triple Crown and the oldest living Kentucky Derby winner, underwent surgery to fuse two arthritic joints in his neck on Saturday, March 2, in Lexington, Ky. This is the second operation of this type the 28-year-old stallion has needed. The first surgery was done in early 2000.

The lead surgeon each time was Barrie Grant, DVM, Dipl. ACVS, of San Luis Rey Equine Hospital in Bonsall, Calif. In 2000, the stallion began showing sudden signs of ataxia (incoordination) after his morning exercise at Three Chimneys Farm. Seattle Slew also was not "straight" behind when he walked. The farm's veterinarian, Jim Morehead, DVM, conducted a neurologic exam and did X rays on the horse, and noted radiographic changes in Slew's lower neck.

Several experts were called into consult on the case, including imaging specialist Norm Rantanen, DVM, Dipl. ACVR. The team recommended a bone scan (scintigraphy) be conducted to help pinpoint the cause. The diagnostic procedure was done on Jan. 16, and Rantanen, Morehead, and internal medicine specialist Bill Bernard, DVM, Dipl. ACVIM, of Rood and Riddle Equine Hospital in Lexington, consulted to determine if the images were significant.

It was decided to also test Slew for EPM, and Bernard did a standing CSF (cerebral spinal fluid) tap on the stallion (then 26 years old). The test results were positive, but not definitive. It was decided to treat Seattle Slew for EPM even though the medications are known to sometimes interfere with sperm production.

There were arthritic changes discovered in three joints in Slew's lower neck, but one was worse than the others. "In foals, you will see one cervical vertebral joint bigger than others, and many times one joint in the adult horse will be more arthritic than others," noted Grant.

When deciding how to treat Seattle Slew, Grant and Rantanen drew upon human medicine. Grant's mother had suffered from neck arthritis, and she was treated with injections into the joints. Rantanen had perfected the technique in horses over the last four to five years, and the decision was made to inject the joint with cortisone to relieve the pain the arthritis was causing. This is not an easy procedure, noted Grant, especially in the standing, sedated horse, and especially in a joint that has changes in its structure due to arthritis.

Rantanen used ultrasound to guide his injections, and Seattle Slew had a dramatic response. Within two days of the treatment, he was walking straight again instead of listing to the right with his hindquarters.
The stallion remained normal for about 17 days, then began to show neurologic problems again. This time his hindquarters were drifting left. The timing could not have been worse for the team of experts treating Seattle Slew. Grant was out of the country, Rantanen was traveling, Steve Reed, DVM, Dipl. ACVIM, of The Ohio State University, who is skilled in vertebral treatments of horses, had just been injured by a horse and was unable to step in to help.

Grant's partner, Joe Cannon, DVM, Dipl. ACVP (Equine), had observed the technique many times, and he had practiced on a horse belonging to Grant's daughter. He was called in to inject the three joints on Slew, and performed the technique successfully.

The stallion received two more rounds of intervertebral injections, showed pain relief, and got a few mares in foal. Then he began to show problems again.

"The horse's original owners, Mickey and Karen Taylor, and the owners of Three Chimneys Farm where he stands, were all very forward-thinking," said Grant. They needed to do a myelogram on Seattle Slew, but that required another trip to Rood and Riddle Equine Hospital and anesthesia. (A myelogram is a special radiograph taken after dye has been injected into the spinal canal. The dye reveals narrowing of the spinal canal.) The procedure was performed successfully by Bernard on a Sunday morning the last weekend in March of 2000 with Grant and Rantanen in attendance.

"We found stenotic changes between the sixth and seventh cervical vertebrae. (There are seven cervical vertebrae, numbered from the top of the head going down toward the withers.)

The options were discussed, and it was decided that to give the horse relief from the arthritic changes from where those two vertebrae were pressing into the spinal canal. A "Bagby basket" would be inserted to fuse the joint and relieve the pressure. Grant in the 1980s helped perfect this technique, which was based on work done by human surgeon George Bagby, MD. (He was unable to attend the first surgery, but was present for the recent one.)

Grant's regular surgical team was brought to Lexington, and they used the facilities and additional personnel at Rood and Riddle Equine Hospital for the surgery. Included on the team were anesthesiologist John Hubbell, DVM, Dipl. ACVA, of The Ohio State University (who had worked on many of these types of "wobbler" surgeries with Reed).

The surgery was performed on April 2, 2000, on a Sunday morning. It took 75 minutes from induction to recovery. "The old horse rolled himself sternal, we helped him get his legs out right, and we helped him stand on his own," said Grant. An hour later, he walked from recovery to his stall.
"He makes everyone look like champions," said Grant.

He had a course of rehabilitation that included lots of stall rest and a gradual return to limited exercise. He was taken off EPM medication. He returned to the breeding shed in 2001 and completed his book of mares, getting 90% in foal. He was monitored closely, but showed no more problems.

The stallion was videotaped daily and the tapes reviewed on a weekly basis by Grant. "The old horse was enjoying life," said Grant.

Then in January of 2002, Seattle Slew again began showing neurologic signs. "We didn't know what the problem was," said Grant. "Was it another lesion, or something else?" The semen evaluation done by Terry Blanchard, DVM, Dipl. ACT, of Texas A&M University showed the stallion was still doing well reproductively.

It was clear that Seattle Slew was having more neurologic problems based on exams done by Morehead and Grant's other associate, Mark Martinelli, DVM, Dipl. ACVS. It was decided that in order to do what was best for the horse, another myelogram needed to be performed. On Tuesday Feb. 26, Seattle Slew was again taken to Rood and Riddle Equine Hospital and Bernard performed a myelogram. Rantanen was there to read the resulting X rays and offer his suggestions on how to proceed.

"The surgery we did in 2000 to implant the basket had successfully re-established the normal width of the spinal canal at C6-7," said Grant. "But, there was now a significant narrowing of the canal at C5-6. We decided to do go ahead and do surgery on Saturday (March 2)."

Included in the surgical team were Grant, Rantanen, Hubble, Steve Trostle, DVM, Dipl. ACVS, an associate, Greg Evans, DVM, an intern, and Wendy Dagley, RVT, a technician from Grant's hospital in California.
The design of the Bagby basket implants had been slightly modified from the 2000 model, based on its use in human spines. The new basket could be twisted into place instead of having to be tapped into the bone of the spinal column. This, said Grant, minimizes trauma to the area and improves the support for the area. It also helps the bone grafts to heal quicker, allowing faster fusion and immobilization of the affected area.
In older horses (as in older humans), the bones become soft and can be compressed or crushed more easily than in a younger animal. The new Bagby basket also helps prevent this complication.

"I felt better after the second surgery than I did the first," said Grant. The experts had debated whether they should do some prophylactic placement of baskets to prevent future problems, but it was decided to do just what was needed.

On Tuesday, March 5, X rays showed that everything was still in place and healing nicely, and Seattle Slew was comfortable with two joints fused in his neck. More radiographs will be taken in six to eight weeks to make sure the bone fusion is progressing.

When questioned about the additional problems of operating on a horse as old as Seattle Slew, Grant said, "The perception has been that older horses don't take surgery as well, but that's not true today. We operate on 30-plus year-old horses for colic successfully. It's as much economic as anything (what drives the decision to do surgery on older horses).
Seattle Slew had gotten two mares in foal so far this year. Grant said recovery time should be six to eight weeks.

"We're not even going to think about whether Slew might ever return to service until he tells us he's healthy, happy, and fully recovered," said syndicate manager Taylor. Seattle Slew is the only Triple Crown winner to have sired more than 100 stakes winners, and one of only a handful of Thoroughbred stallions to have reached that milestone. He has sired seven champions, and his get have earned more than $75 million.

Article Reprinted with permission of The Horse.

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