Smaller Endoscopes Lead to Less Invasive Treatments for Navicular

A novel twist to an existing surgical procedure is creating new opportunities for healing a long-recognized form of lameness, according to Italian researchers.

Navicular treatment

The tip of the mosquito forceps is inserted in the navicular bursa through the T ligament as described in the transthecal approach.

Palmar foot pain (a modern term for navicular syndrome) cases are now being treated with endoscopes placed into a horse’s foot. These tiny telescopes allow surgeons to look directly into the tissues surrounding the crescent-shaped navicular bone within the hoof. Through this diagnostic process, the tissues are cleaned and separated, which frequently leads to healing without further surgery.

Previously, surgeons cut the T-ligament (located over the navicular bone) in order to better access the tissues. But with new, smaller endoscopes, veterinary surgeons can now spare the ligament in certain cases, said Massimiliano Scandella, DVM, PhD, researcher in the veterinary clinical sciences department at the University of Milan and primary author of the study.

Scandella and his colleagues practiced the specific endoscopic techniques, called bursoscopies, in the navicular bursa of 20 cadaver limbs using endoscopes as small as 2.7 mm in diameter. The navicular bursa is a fluid-filled structure between the navicular bone and the tendon and is often a source of inflammation and infection in palmar pain cases. In usual practice 4 mm diameter endoscopes are used.

Once the researchers completed this initial work on cadavers, they performed their new technique on a 14-year-old mare with palmar pain syndrome in both front feet. Only the left leg was treated for the sake of comparison. The mare showed marked improvement after the surgery and appeared to still be comfortable walking on the left leg six months later, Scandella said.

"The initial training on cadaveric limbs was crucial to recognize the anatomical landmarks and improve the insertion technique," he said.

"With the smaller endoscope, we were able to enter without opening the T-ligament and visualize all the structures," Scandella said. "So now we know it's probably not necessary to cut the ligament in most diagnostic procedures." However, if the navicular bursa requires further surgical intervention (for example, to debride and curette the lesions [remove dead tissue]), it will be necessary to open the ligament, he added.

"Many times owners are unaware of the complexity of this region of the foot, and so they can't understand why it's so difficult to know exactly where the pain is coming from and why it's so hard to treat," Scandella said. "But this procedure, because things are more visible and more accessible, is making that a little bit easier."

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.