Erin Contino, DVM, MS, Dipl. ACVSMR, assistant professor of Equine Sports Medicine and Rehabilitation at Colorado State University, in Fort Collins, described treatment strategies and the science behind them during the 2020 American Association of Equine Practitioners Convention, held virtually.
Breaking the Pain Cycle
After a veterinarian makes an accurate diagnosis of what’s causing a horse’s back pain—based on history, the physical and clinical exam, and imaging—he or she can choose from a variety of modalities to control it. Contino listed some of the most common:
Focal injections. The main injectables veterinarians use for back pain are corticosteroids. “They’re potent anti-inflammatories, and I find them to be one of most effective ways to get ahead in the game of treating back pain,” said Contino.
Where and how many times she administers them depends on the diagnosis. For kissing spines, for instance, Contino said she most frequently injects corticosteroids regionally, between the affected spinous processes. Research has shown this method to be quite effective, she said, citing one study in which it resolved kissing spines pain in 34 (89%) of 38 horses. Recurrence with this treatment, however, is common.
Contino said she injects more specific locations if she has a site of pain to target, such as with intra-articular facet joint injections.
Systemic medications. If she suspects a horse’s back pain is neuropathic (nerve-related), Contino said she might treat systemically with non-steroidal anti-inflammatories (NSAIDs). However, she hasn’t found NSAIDs to be very effective for treating axial skeleton pain.
“I might use systemic corticosteroids if the horse is unresponsive and I suspect they have dorsal root ganglionitis (inflammation of a spinal nerve) or windup pain,” she said.
Contino also commonly treats horses with back muscle pain systemically with methocarbamol, a centrally acting muscle relaxer that reduces spasms.
Bisphosphonates. While this bone drug is only FDA-approved to manage pain associated with the navicular region of the foot, one study has shown it to also be effective at treating horses with thoracolumbar (from the withers to the pelvis) osteoarthritis. Contino said it might, therefore, be indicated for horses with bone-related back problems, so long as they’re over age 4 and not being administered NSAIDs concurrently.
Mesotherapy. She said she might use mesotherapy (a series of injections into the middle layer of the skin to help relax the muscles) if horses have muscle or myofascial pain.
Shock wave. “This therapy can be very effective in breaking the pain cycle,” Contino said. “I use it quite a bit on backs—the only reason not to is cost.” She cited a 2019 study showing that horses became less painful with each shock wave treatment (horses typically receive a series of three or four treatments).
“It’s a great choice if you have horses that can’t have corticosteroid injections (e.g., metabolic horses) or a good adjunct to corticosteroids, a way to space out injections,” she said.
Shock wave can help relieve pain in the thoracolumbar epaxial muscles (those running along either side of the spine), middle gluteal muscles, or sacroiliac region and that stemming from ligamentous injury.
Laser. “A lot of clients have access to low-level laser, so this can be a good adjunct therapy, as well,” said Contino. She described a study of competing Quarter Horses with acute lower back pain that experienced decreased epaxial pain, trunk stiffness, and muscle hypertonicity (tension) after low-level laser therapy.
Acupuncture. This complementary therapy also shows promise for treating back pain. In one study, horses with chronic lower back pain saw a significant decrease in thoracolumbar pain after receiving electroacupuncture. The analgesic effect lasted up to two weeks, said Contino.
Chiropractic. “A treatment that often goes along with acupuncture is chiropractic,” she said. In a 2008 study of 38 horses without back pain, the group that received chiropractic had the greatest increase in mechanical nociceptive thresholds (the amount of pressure required to induce a pain response), indicating it should reduce back pain.
Kinesiotape. While this therapeutic taping method has a number of applications, Contino said for back pain she most commonly uses a myofascial restriction pattern to lift the skin over an affected area and relieve tension.
Surgery. Contino said she can manage most back cases without resorting to surgery, but that standing interspinous ligament desmotomy can benefit horses with kissing spines. In one study this procedure had a 95% success rate and better (24-fold) long-term outcomes than corticosteroid injections.
“I think that while surgery carries a very good success rate, I do always treat them once first to make sure it’s effective before doing something more invasive,” she said.
Contino noted that she rarely uses just one of these therapies as her only line of defense. Rather, she combines them based on the diagnosis and horse’s response.
Increasing Strength, Function, and Stability
Once you’ve gotten a horse’s back pain under control, it’s crucial to build their strength to keep it that way. “Get these guys to th.e gym,” said Contino. Useful strengthening exercises include:
Dynamic mobilization. Core exercises such as sternal lifts and lumbosacral tucks can help strengthen a horse’s core and multifidus (along the spine) muscles. Contino cited a study in which researchers performed dynamic mobilization exercises on horses five days a week for three months (five reps of 10 exercises) and noted increased cross-sectional areas of the multifidus muscles and better symmetry between left and right sides.
Gymnastics Activities such as backing, circling, and walking over raised poles can enhance your strengthening program, said Contino. One study showed that performing these exercises three days a week for three months in conjunction with dynamic mobilization exercises increased multifidus muscle cross-sectional areas more than dynamic mobilization alone.
Elastic resistance bands. Contino said she uses these bands frequently when rehabilitating horses with back pain. She described a study using a band system up to 30 minutes three times a week for four weeks that found it increased the study horses’ dynamic stability.
Whole body vibration. While Contino doesn’t find vibration therapy to be nearly as useful as things like core exercises and resistance bands, she said researchers observed a significant increase in multifidus muscle symmetry and cross-sectional area in horses standing on a vertical vibrating platform for 30 minutes, twice a day, five days a week, for two months.
Contino said she finds back pain cases extremely rewarding to treat.
“These horses can often have really severe performance issues and be very uncomfortable, but are so often responsive to treatment,” she said. “I can’t overemphasize the importance of an accurate diagnosis, because that allows you to individualize your treatment.”
When formulating a back treatment plan, she added, always remember the two pillars: break the pain cycle and build strength.