Remember fifth-grade paper mâché projects? You inflated a balloon and covered it in strips of glue-soaked paper that dry hard. Then you popped the balloon while keeping the hollow shell and decorated it into a cute little r-ound-bellied rabbit or penguin?
Well, your horse’s skull is kind of like that hollow shell—at least right over the sinus cavities, according to one equine surgical team. And all it takes is a good kick to that skull bone to leave a dent into the hollow space beneath it, just like it would if someone kicked your paper mâché penguin.
To return that dented skull bone back to the right shape and protect the structures beneath, surgeons can follow the paper mâché concept: inflate a balloon.
“This is a relatively inexpensive method for sinus fracture repair with very good functional and cosmetic results,” said Alison Gardner, DVM, MS, Dipl. ACVS, ACVECC, of the Department of Veterinary Clinical Sciences at The Ohio State University, in Columbus.
Dipped Nasal Bone, Blocked Internal Passages
Horses with facial fractures involving the sinuses risk not only a depressed appearance but also inhibited airflow through the nasal passages and poor drainage of the sinuses and the tear ducts. “They might have a blocked tear duct or infections like sinusitis throughout their lives,” Gardner said.
To avoid these issues in two weanling fillies, Gardner and her fellow researchers successfully repaired their skull fractures over the sinus cavities using this balloon technique. Specifically, they used a medical balloon with a Foley catheter, she said.
They developed the idea for the use of the balloon after reading about similar techniques in human skull fractures, said Gardner. Additionally, a 2016 case study involved an adult horse with a similar fracture; in that case, surgeons at Auburn University in Alabama used a saline-inflatable human breast implant to fill the cavity below the fracture. However, she said, that method would have been not only more expensive (especially because of the invasive surgery to remove the implant later) but also impractical due to the size of the weanlings’ heads, she said.
The Surgical Technique
Before performing surgery, the foals underwent computed tomography (CT) scans to assess their tissue damage, said Gardner. Based on those scans, the surgical team designed customized strategies to repair each filly’s injury (both had sustained kicks to the face).
With the fillies under general anesthesia, the team pieced the broken bone parts back together like a puzzle, suturing them in place. However, the attached bone fragments continued to collapse into the sinus cavity, Gardner said. she and her fellow researchers inserted the Foley catheter and balloon through a small hole drilled through the closed skull. They used the catheter to flush the cavity, clearing it of blood and infection, and then inflated the balloons with saline to fill the cavities and regain the skull’s correct shape. They left the catheters in place—emerging through the hole in the skull—to allow for drainage.
“We re-establish drainage from the nasolacrimal duct on the ocular side through the sinus, rather than traversing down the bony canal to the nose, which had been disrupted in the fracture,” Gardner said.
Recovery, Healing, and Performance
Within four weeks, Gardner’s team sedated the fillies and surgically removed the balloons and catheters and closed the holes, she said. The fillies recovered well, with full function of their respiratory routes, eyes and tear ducts, and sinuses. Over the years, they were able to train and compete as intended, Gardner added. One became a barrel racing Quarter Horse with very satisfactory results, and the other competes at high levels of eventing.
“What’s really interesting about these two cases is that both of them went on to compete at very high levels of athletic performance, which requires sufficient oxygenation,” Gardner said. “Obviously these horses were not dealing with compromised airways following their injuries and repair.”
Cosmetically, the mares both have few visible signs of their past fractures, she said. While one of them has a slight unevenness in the face, that could be because she pulled out her own catheters before the end of the set four-week healing time, Gardner explained. Even so, the filly’s appearance was very good considering her initial injury, she said.
A Dented Shape, Only After the Swelling Recedes
Horses suffering skull fractures such as these don’t always appear to have a “dent” at first, said Gardner. Sometimes, the swelling in the area masks the damage to the bone. “If you see a facial injury in your horse, monitor closely for swelling as well as how well air is flowing through each nostril,” she said. “You can’t always see the fracture at first, but the earlier you can get a fracture like this repaired, the better the outcome will be.