A new way to correct a respiratory condition commonly called “roaring” has returned a Thoroughbred mare to the track, earning her owners more than $300,000 since her recovery in 2006.

Raging Rapids, a strapping 5-year-old mare, won a race for Victory Thoroughbreds LLC, a group that claimed her for $10,000 last year. But even in the winner’s circle, she showed the classic signs of laryngeal hemiplegia, breathing noisily as she struggled for air.

The condition is caused by a nerve dysfunction affecting the left side of throat. The nerve dysfunction results in a muscle that fatigues easily and can’t hold the throat open when the horse exerts itself. The left side of the throat collapses, restricting the airway and causing the telltale “roar.”

After performing endoscopy, Dan Hanf, VMD, of Marlton, N.J., recommended surgery at University of Pennsylvania’s New Bolton Center. He told the horse’s owners there was a research study underway to investigate a modification to the surgical procedure that has been used for over 30 years.

Eric Parente, DVM, Dipl. ACVS, associate professor of surgery at New Bolton, had developed the modification.

“Tieback surgery pulls the one side of the throat into a fixed, open position so it doesn’t ‘suck down’ or collapse when horse breathes,” Parente explained. “This is an unnatural position for the throat, giving horse the advantage of air, but if the tieback (sutured into the muscle) is not positioned just right, it makes it impossible for the horse to protect its airway from food or water.”

The result has been a lot of failures. A study in Great Britain showed that even when the surgery appeared to succeed, 30% to 40% of horses lost a significant amount of abduction (opening) after the operation.

Parente’s modification is performed when the surgeon reaches the larynx. The surgeon cuts through the muscle over the joint, opens the joint, and debrides the cartilage. Then, under videoendoscopic guidance, he puts the sutures in the joint to pull the left side open.

“This better positions the sutures, the joint fuses, and it provides a more stable, long-term fix for the horse,” Parente said.

Horses generally go home the day after the hourlong procedure, with about a month of stall rest and hand-walking before they can return to work.

That’s how it went for Raging Rapids, who won her first race back by three lengths, just two months after the surgery. Since then, the mare has had a dozen more wins, three of them in stakes races. Raging Rapids was named “Claiming Horse of the Year” by the Pennsylvania Professional Horseman’s Association and the Pennsylvania Horse Breeder’s Association.

“We had a perception this mare was underperforming, due to a breathing problem,” said Lou Cacchio, who heads up the group that owns the horse. “We could see the potential in the horse. Needless to say, we are very pleased with Dr. Parente’s work”

So far, 70 to 80 horses have received Parente’s modification. Study data is being analyzed now, but reports from owners and their vets indicate that many of the horses have returned to work even at the highest level of competition.

“This is now my standard procedure for this disease process,” Parente noted. “I do it on all breeds of horses, but if it works on racing Thoroughbreds, that is the ultimate test