Shock wave therapy in equine practice is exactly what it sounds like: sending waves of acoustic energetic through a horse’s body. After having treated horses with extracorporeal shock wave therapy (ESWT) for nearly 10 years, Bonny Henderson, DVM, CERP, has seen significant healing and protective benefits to horses’ musculoskeletal systems.

“The more people realize how useful shock wave is, the more I’m surprised that others still haven’t even heard of it,” said Henderson, who runs Henderson Equine Clinic, in Avon, New York. “It’s pretty amazing.”

To better understand the practical side of shock wave therapy in horses, we’ve asked Dr. Henderson about her ESWT knowledge and experience.

Is it surprising to you that just emitting sound waves through a horse’s body would have a healing effect?

I’m always amazed at the body and how interconnected everything is. No, it doesn’t surprise me at all that shock wave has such a dramatic effect. I think it’s impressive how far along the modalities have come, so that now we can focus the waves and pulse them into a specific site and really tailor them to do what we want them to do. You can drive energy wherever you want to drive it! The waves generated by compression of a piezo crystal can be focused for depth and shape of the wave allowing very specific targeting of injured tissues.  The wave generated by a hydroelectric pump derived electricity provide a broader, less focused treatment.

What are the most common health problems you recommend shock wave for?

Most people think immediately about treating tendons and ligaments and their insertion points into the bone. That’s what we hear most about in human medicine and so are most familiar with.  Honestly, it’s hard not to recommend shock wave for pathologies in those sites because of how much it does.  (In our clinic we) target cartilage, bone, menisci, muscle and fascia.  ESWT affects almost any kind of cell you want to stimulate: tenocytes (tendon cells), fibroblasts (which form connective tissue, ligaments, skin), osteocytes (found in mature bone), chondrocytes (for cartilage formation) even endothelial cells (in skin and vessels). So we can treat most things effectively with ESWT.

Is it useful to combine regenerative therapies with shock wave?

We follow up all our PRP (platelet-rich plasma), therapies with shock wave. It’s amazing because, since we can put acoustic energy into almost any type of cell we want, like platelets or tenocytes, we can enhance the effectiveness of regenerative therapies. Research is really catching up on what many of us in the field have (suspected) for a while— that shock wave is helpful for many of these treatments, especially for PRP. We always tell our clients that their horse’s PRP treatment is going to work better if they follow up with shock wave.

Can shock wave help with colic, cardiac issues, or other internal illnesses?

To my knowledge, you can’t use shock wave on an internal organ, at least not in horses yet. In humans, ultrasound waves are used for treating bladder stones, for example. But you lose energy at every tissue interface, so it would be hard to do that in horses as you go through the skin, fascia, muscle, and the other tissues beneath it trying to reach a particular organ. In addition, the shockwaves will not transmit through gas, air.  The waves will dissipate in any air between the abdominal wall and the organ.   As for the heart, you really wouldn’t want to do that anyway because the heart pumps in response to electrical impulses, and you don’t want to interfere with that signal.

How many shock wave treatments do horses need?

The number of treatments varies according to the pathology and injury. But if you’re looking at your standard ligament injury, you can plan on three-to-four treatments, two to three weeks apart. For chronic muscle treatment you might need more initially but then can drop down to just once or twice a year with some touch-ups, a couple of times closer together, like three or four weeks apart. If you’re following up on regenerative medicine, you’ll want to do shock wave right away, and then come back and do it again in about two to three weeks. But, really, the horse’s response to treatment determines what you do from then on.

How do horses react to receiving shock wave therapy?

Usually, the horse will just stand there and then if they like a spot, they’ll shift underneath for me to reach the site they are enjoying.  They often lick, chew and yawn throughout the treatment. If horses get excited about it, the veterinarian needs to start at a low frequency and work up as they relax into it. Horses generally tolerate it really well. But it’s important for people to remember that the therapy has analgesic effects, so they can inadvertently injure their horse in the first several days after treatment if they work them too much.

How should owners prepare their horses for shock wave therapy?

You don’t want any air between the probe and the horse because that loses energy. So horses should be clean and well-groomed, and any shedding hair should be cleared off. The horse might hear popping that could surprise them. So that might take a little habituation.

What horses are not good candidates for shock wave therapy?

If a horse has an acute injury, you don’t want to drive energy into a wound that’s still trying to heal through the acute stage of injury, especially if it hasn’t stopped bleeding. You should also avoid shock wave anytime you don’t want to stimulate growth, like with cancer tumors or granulation tissue, or splints where you don’t want massive bone growth. Also, if you don’t have a definite diagnosis, you could be wasting your time and not even treating the right thing.

Is shock wave just for rehabilitation, or can it be used preventively?

We’re seeing much better dynamic, long-term responses than when we first started using shock wave therapy nearly 10 years ago. So now we’ve basically incorporated it into all our sport horse and rehabilitation programs. Because if you can keep your horse symmetrical, and you can keep them functioning and balanced, left to right and front to back, the number of injuries just decrease drastically. When you catch things before horses reach that critical threshold where they get injured, you can often prevent that from happening. And that’s where my heart is—trying to prevent these injuries. Healing them once they happen, of course, but trying to get the horse to perform at his top level without having to deal and cope with these other issues.