When Chanel B 2 steps into the ring in the high adult amateur jumpers or dives into a hay bag, many people won’t even notice she’s missing a major part of her anatomy: her lower jaw.
Being down a few inches of bone hasn’t stopped her from regularly bringing home ribbons from the Winter Equestrian Festival (Florida), a feat her owner Karen Long Dwight never expected.
“It’s so miraculous because we really thought we were going to lose her,” Dwight said. “We thought she’d never come back.”
In 2017, Dwight got an unusual call from Carine Pignatti, the amateur who was leasing “Nellie.”
“One of their grooms looked in her mouth and noticed she had this tiny little lump in her mandible that was slightly spongy, and when you pressed on it, [it] didn’t bother her,” Dwight remembered.
Nellie had an accomplished résumé, winning the high junior/amateur-owner jumper championship at the Washington International Horse Show (District Of Columbia) and taking team silver and individual bronze at the 2014 Alltech/FEI North American Young Riders Championship (Kentucky) with Tori Colvin. She had a few different riders at the beginning of 2017 before Pignatti started competing her in the adult jumpers in June. They discovered the bump at the end of their show season in October.
Dwight’s veterinarian was stumped. Since the lump didn’t seem to bother the mare, they decided to keep an eye on it. However, a few weeks later it had grown to a startling size and had begun to push Nellie’s lower teeth out of alignment. Dwight sent Nellie to Palm Beach Equine Clinic in Wellington, Florida, where Dr. Weston Davis, DVM, DACVS, took the case.
A radiograph revealed that the lump was a tumor. One image showed a round, asymmetrical blob poking up against the bottom gum and dipping far down into the bottom lip. Davis biopsied the mass and ordered a computerized tomography scan that created a three-dimensional view of the jaw, showing the surgery team where the edges of the tumor were.
The mass was an ameloblastic fibroma, a rare type of tumor. Davis said ameloblastic fibroma are unlikely to travel to other parts of the body but are known to grow quickly in their chosen area. The best solution was to remove the tumor by performing a partial mandibulectomy: cutting away part of Nellie’s lower jaw.
“We went home and cried. We said, ‘How will she ever be able to eat? How will she be able to have her peppermints? How will she eat grass again?’ We were just horrified,” said Dwight. “Dr. Davis was very positive about it and said she’d be just fine. We were completely sure we’d have to retire her and get someone to feed her bran mashes all the time, but he kept saying, ‘Horses figure it out. They don’t mind like a human would mind.’ And he was right.”
Davis said a mandibulectomy is an uncommon procedure in horses; he’d never done one himself and could only find a handful described in veterinary literature. But after consulting with a colleague at the University of Tennessee, he felt comfortable with the task.
“It didn’t bother me or make me nervous,” Davis said. “I’d like to make it sound fancier, but it’s not a very delicate procedure really. I thought it was fun and cool to do something different.”
The tumor’s position made Nellie a good candidate for surgery. The equine lower jaw is comprised of two hemi-mandibles that join in a V shape at the symphysis, which is the area where the bit lies or the “bars” of the mouth. The mandible continues as one piece in front of the symphysis, and that’s where the horse’s incisors or front teeth are located. Nellie’s tumor didn’t extend beyond the symphysis, so Davis could remove it and leave a small segment of bone joining the two sides. This meant the right and left hemi-mandibles wouldn’t be floating around separately.
While Nellie was under general anesthesia, Davis cut the bone, removed the jaw and the tumor, and rounded off the edges of the mandible remaining in Nellie’s mouth. (Perhaps surprisingly, this type of procedure is often done with the horse standing under sedation, but Davis thought anesthesia was a better option for a sensitive horse.) Then, he stitched together the remaining tissue from her gums.
Nellie’s surgical site healed quickly, and she went home in a few days.
Dwight had worried about Nellie’s diet but was pleased to discover she quickly learned to use her tongue and lower lip similarly to her bottom teeth—she can grab things and easily move food to the back of her mouth to her molars. She believes Nellie has gained weight in the year since her surgery.
In hindsight, Dwight wonders if Nellie did suffer some discomfort from the mass. Previously after landing off a warm-up fence, Nellie had a habit of flipping her nose, which Dwight thought was a behavioral quirk. Now, she wonders if the jarring motion was shaking something and making the mass sting. Since the surgery, the behavior has stopped.
A few weeks after the surgery, Nellie was back to light work in a hackamore, and to everyone’s surprise, she went back to a bit. In fact, just a few months after the surgery, Nellie returned to the show ring in time for the end of WEF in early March 2018.
“She’s very popular with the crowd. They all love her,” said Dwight. “The funny thing is she doesn’t really hang her tongue out when she’s concentrating out on course. She’s very serious. She loves her job.”
At Nellie’s one-year follow-up appointment, Davis performed a CT to check for signs of the tumor reoccurring. The images all came back clean.
“You should see her graze,” Dwight said. “You’d never guess.”
Do you know a horse or rider who returned to the competition ring after what should have been a life-threatening or career-ending injury or illness? Email Kimberly at firstname.lastname@example.org with their story.