Dog regains use of leg after unique muscle transplant surgery

Unusual injuries require unusual solutions, something Michael Pavletic, DVM, DACVS, has specialized in for more than three decades with his work in veterinary plastic and reconstructive surgery.

When a 6-year-old dog with a severely injured leg was brought in to the AAHA-accredited Angell Animal Medical Center in Boston, Mass., where Pavletic is the director of surgery, he could tell he was dealing with something beyond the scope of standard surgeries.

According to the owner, the dog named Bella had fallen off a piece of furniture and immediately pulled up lame, holding her right foreleg in an unnatural position. Pavletic said Bella’s leg pointed almost straight back toward her tail.

“Someone made the comment that she almost looked like in the Olympics - the baton passing in the relay races,” Pavletic said.

The dog’s owners consulted with a few different veterinarians in the months following the injury and tried physical therapy that proved unsuccessful. Finally they sought the help of Pavletic, whose distinguished career has included many unusual cases and the development of more than 50 different surgical procedures.

Pavletic’s initial examination revealed that Bella’s leg had probably experienced vascular trauma resulting in ischemia to the triceps muscle group. He surmised that the trauma had caused the triceps muscles to contract and elevate the dog’s leg to the side, which also resulted in atrophy.

It would have been possible to sever the triceps muscles in order to straighten the leg, Pavletic said, but it would have left the dog with a non-functional leg that would probably have been better off amputated.

Fortunately, Pavletic's extensive lineup of invented surgeries included one that could potentially be modified to save her leg.

Finding a non-traditional solution

Pavletic recalled the success he had experienced with a procedure he called the latissimus dorsi muscle flap technique, which he developed years ago for reconstruction of a thoracic wall.

During the procedure, Pavletic surgically redirects a portion of the latissimus dorsi muscle - a muscle that he says “has a lot of versatility” - into the area of the injured muscle. Through surgery and post-operative therapy, the muscle taken from the back can be "trained" to function in the place of injured muscle groups such as the triceps.

Years before he took on Bella's case, Pavletic had successfully used the technique to help a dog that had experienced trauma in the triceps.

“I have used a portion of that muscle in a prior case of a small Chihuahua-cross that had a portion of the triceps muscle destroyed from a bite wound,” Pavletic said. “By rotating a portion of that latissimus dorsi muscle into the defect, I was able to bridge that muscle so that it could function, and that dog did quite well.”

Pavletic modified the procedure for Bella's injury and performed it on her, elevating the muscle flap and pivoting it into the correct position. The entire procedure only took an hour, he said. 

“To me, this is a very simple surgery and just a variation of a theme that I’ve done for over 30 years,” Pavletic said. “It was not an expensive, elaborate procedure; it was freeing up the muscle and then using some intraoperative clinical judgment on adjusting the tension.”

Ensuring success through post-operative therapy

The surgery was only the first step in the endeavor to repair the dog’s leg, Pavletic said.

Once the latissimus dorsi muscle was re-routed into the leg, Bella had to go through rigorous physical therapy to train the muscles to function properly, as well as teach her how to effectively use the new muscle.

“That also required post-operative physical therapy to improve range of motion and bring the remaining atrophied muscles in the leg back to a more functional size. The second thing is that by physical therapy, we have to train the dog to contract the latissimus dorsi muscle in order to move the leg,” he said.

Following extensive work with a local physical therapy hospital, with much time spent on an underwater treadmill, Bella has regained close to normal function in the leg and “walks almost normally on the leg at this point,” Pavletic said.

“I haven’t seen the dog over the past couple of weeks, but certainly there is treadmill videotape showing that the dog is using the leg as well as the other leg,” Pavletic said. “And the owner has basically commented that he thought the dog was essentially back to normal.”

Potential future applications for the procedure

Although Bella’s injury was unusual, Pavletic said there are several other instances in which the latissimus dorsi muscle flap technique could prove useful. He mentioned vehicular trauma, bite wounds, and cancer as occasions where muscles may need to be repaired using the latissimus dorsi muscle flap technique.

“If we have dogs coming in with cancer involving specifically the triceps muscle group, we may be able to selectively remove that muscle now and replace its function in order to preclude having to, for instance, amputate the dog’s leg,” he said.

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