Inciting causes of laminitis include dystocia (difficult birth), placentitis (inflammation of the placenta), colitis (of the colon), grain overload, septicemia (infection in the bloodstream), and contralateral (occurring on opposite sides) limb lameness. And, said one equine podiatrist, the earlier a veterinarian can intervene and begin treatment, the greater chances of success, which in many cases means saving the horse’s life.
“Chronic laminitis is defined in the literature as those cases ranging from 72 hours to several weeks after the onset of pain,” said Sammy Pittman, DVM, of Innovative Equine Podiatry and Veterinary Services, in Collinsville, Texas, at the 2018 American Association of Equine Practitioners Convention, held Dec. 1-5 in San Francisco, California.
Regardless of why a horse develops laminitis, the end result is essentially the same: the lamellae, which anchor the coffin bone to the inner hoof wall, fail. When this occurs, farriers and veterinarians must focus their efforts on the mechanical component of treatment.
“It’s imperative to think about how much damage presently exists, as your mechanical therapy will be guided by the damage assessment,” Pittman said.
He used the example of a laminitic horse being examined for the first time by a veterinarian four to eight weeks post-onset—clearly not a case identified early in the disease process.
“At this point, the mechanical treatment of choice would be highly dependent on a damage assessment protocol and include shoeing with fully rockered wedges (aka banana or rocker shoes), static wedges, and even deep digital flexor tenotomy (surgical transection of the tendon that runs down the back of the pastern and connects to the coffin bone),” said Pittman.
When it comes to diagnostic testing, he said veterinarians rely heavily on radiographs (X rays), including venograms using contrast material to highlight the blood flow within soft-tissue components inside the hoof.
“Venograms offer better visualization of the soft tissue that is compressed and displaced relative to the degree of lamellar structural failure,” Pittman said. “Serial radiographs and venograms provide the opportunity to measure various parameters to monitor the health and recovery, such as sole depth”
While many practitioners focus on the degree of sinking or rotation of the coffin bone, he said it’s also important to consider how the soft tissue highlighted in the venogram is affected.
“Other factors to consider include whether or not the horse has a club foot, low heel, or any medial or lateral (toward or away from the horse’s midline, respectively) imbalances,” said Pittman. “These pre-existing abnormalities are likely to have predictable increased damage in certain areas depending on the exact conformational defect.”
Moving on specifically to shoeing, Pittman recommended practitioners consider treating chronic laminitis cases based on the current level of damage and to picture each case on a “damage ladder.”
“The higher level of damage and the higher you climb on the damage ladder requires a greater level mechanical therapy to alter loads to healthy components,” he said.
- Applying rocker or banana shoes to horses with low- to midscale damage;
- Applying a static wedging system, such as a NANRIC Ultimate, a type of wedge shoe, or a comparable wedging apparatus, to horses with midscale damage.
- Performing a tenotomy of the deep digital flexor tendon on horses with high-scale damage to relieve tension on the coffin bone and stop additional rotation, followed by aggressive shoeing. Shoeing prescriptions vary depending on the severity of the condition and the horse’s individual needs.
“Repeat radiographs and venograms will be required when managing horses with chronic laminitis to let you know whether or not you’re moving in the right direction,” said Pittman. “And at the end of the day, it’s important to reassess and re-evaluate cases, both successes and failures, to learn from those cases and make improvements to your treatment approach with future cases.”