In certain cases of navicular disease, drilling a hole into the navicular bone--a procedure called core decompression that's commonly used to treat human osteonecrosis (bone death caused by poor blood supply to the area)--might provide a new treatment option for veterinarians. According to Carl Kirker-Head, MA, Vet MB, Dipl. ACVS, ECVS, associate professor of equine surgery at Tufts University's Cummings School of Veterinary Medicine and lead researcher on the study, the goals of this procedure are to ease a horse's pain by relieving pressure and to stimulate new bone growth.
"Horses with navicular disease have an elevated pressure inside the navicular bone," said Kirker-Head. "What we are trying to do by drilling a hole is to relieve the abnormally high pressure encountered in navicular disease and attempt to redirect the bone healing process in a manner that will be more favorable to the bone."
Surgeons perform this core decompression surgery on humans who are experiencing pain caused by increased pressure within a dying bone; the procedure is meant to decrease the pressure and, in some cases, stimulate new bone growth. In horses, sustained pressure on the navicular bone by the deep digital flexor tendon secondary to abnormal forces placed on the tendon results in abnormal remodeling of the navicular bone. In response, the bone begins to degenerate and becomes edematous (fluid-filled) and painful. Kirker-Head and his colleagues performed an experimental in vivo (in the live horse) study to see if the same technique would help ease the pain of horses with navicular disease.
To determine if the surgery could be carried out safely in horses and successfully relieve pressure in the navicular bone, the team performed core decompression on six healthy horses. The team monitored the pressure in the foot before and after decompression drilling, and all of the horses had significantly less pressure around their navicular bones after the procedure, Kirker-Head explained. With the exception of mild, short-lived lameness, researchers noted no adverse effects from the surgery.
"Navicular disease is not anywhere near as straightforward as we once suspected," he said. "The disease is considerably more complex and requires a comprehensive approach to treatment. Our decompression surgery is just one avenue to be taken."
Kirker-Head added that the next step in his research is to perform the surgery on a horse with navicular disease and evaluate the outcome.
The study, "Core decompression of the equine navicular bone: an in vivo study in healthy horses," appeared in the February issue of Veterinary Surgery. The abstract is available on PubMed.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.