Invasive surgery has been a mainstay of kissing spines treatment, with proven success. But is this still the best option? Andrea Oakes investigates

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The condition kissing spines can manifest itself in a number of ways. If the bony spinous processes located on the top of the vertebrae touch or rub against one another, the horse can react with anything from subtle performance issues to dramatically bad behaviour.

Pinpointing the exact cause of such pain is notoriously difficult. Detailed veterinary investigations are needed to establish whether touching, or ‘impinging’, dorsal spinal processes are to blame.

Kissing spines treatment options vary. Surgery involving the removal of parts of problematic processes has become more common, but is this always necessary? Would some cases recover if other, more conservative methods were given more time to work?

“We just don’t know,” says equine surgeon Bruce Bladon. “You only have to look at the differences in management and outcomes in people with back pain — and at least they can tell you where it hurts. There are many stories of horses diagnosed with kissing spines subsequently being rehabilitated successfully by management techniques.”

Bruce points out that a colleague in Sweden who has operated on a lot of kissing spines cases has more recently had excellent results — without surgery — with horses sent to a rider experienced in equine rehabilitation and re-schooling.

“This makes sense,” says Bruce. “We’re talking about the normal flexibility of the spine, occasionally resulting in the edges of the bones ‘kissing’. It’s easy to imagine how a different rider or saddle, or increased muscle tone as a result of physiotherapy and a change in work, might prevent this.

“It’s also easy to see how the results of schooling a horse could be so different, depending on the psychology of the rider,” adds Bruce, who believes that kissing spines surgery can, in some cases, have the effect of a placebo.

“The difference in attitude between a rider concerned that their horse is behaving like it is because it has an underlying disease, and a rider who knows that their horse has had surgery for this disease and is now ‘cured’, will be considerable — and quite rightly so.

“But it is major surgery and this has kept a ‘lid’ on the use of the procedure — no-one wants to do it unless they really think it will be beneficial.”

Risks of surgery as kissing spines treatment

Orthopaedic expert Svend Kold agrees that deciding whether or not to operate is not always clear-cut. Much depends on the degree of impingement, the individual horse’s tolerance levels and his lifestyle.

“If he’s an athlete and needs to go places, it needs correcting,” he explains. “The important question is what are people going to do with the horse. Alternatively, can we maintain performance with a twice-a-year steroid injection in combination with physiotherapy and training?”

Svend counters the idea that every horse with kissing spines is dangerously unrideable.

“Much more frequently it’s an under-performance condition, as in the case of a four-star event horse who knocks a fence every other week or the dressage horse who can’t do a canter pirouette to the left,” he explains. “The rider may be unaware of the problem. They may not know until after the operation that they’ve been riding on only 80% of the power.

“There are not many horses you can just train out of kissing spines by improving core structure and raising the back,” he adds. “It’s a difficult diagnosis and each case must be decided on clinical symptoms and X-ray presentation [and sometimes other imaging]. Correct rehabilitation after the operation is equally important, but some horses do need surgery to remove pain before they can confidently engage the back.”

Traditional kissing spines surgery, whether it is carried out under general anaesthesia or using standing sedation and local anaesthetic, is costly and invasive. Are new less invasive procedures the way forward?

“We must evaluate whether we can do a better job under anaesthesia,” says Svend. “You have to weigh up the risk of anaesthesia, but that’s so minimal these days.”

Both procedures can be performed in the standing horse.

Svend adds: “I remove part of the non-continuous [alternate] processes, creating a situation where there is no possibility of any reaction or of regrowth.

“Horses are back in work eight weeks later in the case of surgery on one process, or 12 weeks for more processes. Aggressive rehab helps prevent adhesions and continues development of the back musculature.

“Minimally invasive treatment may be a lesser procedure, but that in itself does not necessarily make it the right answer in every case,” adds Svend, who has performed more than 300 traditional surgeries.“The degree and chronicity [duration] of the X-ray changes may dictate whether minimally invasive techniques are possible, sufficient and the best choice.”

Pioneering kissing spines treatment

One such new treatment has been pioneered recently by equine surgeon Richard Coomer. Called interspinous ligament desmotomy (ISLD), the procedure is carried out under standing sedation through small incisions.

Richard explains that the pain from kissing spines comes from the nerve endings in the interspinous ligaments, the soft tissue structures that link adjacent spinous processes.

“Tension and pressure on these nerve endings gives the horse back pain,” he says. “This causes reflex muscle spasm, which pulls the spines closer and makes the condition even worse. ISLD involves cutting these ligaments to stop nerve stimulation, so the horse experiences a profound improvement in perceived pain.

“In every case there’s a significant improvement post-operatively,” continues Richard who has carried out nearly 100 of these procedures since the first in 2009. “My surgery rids pain but cannot improve on the placing of the spines. But because the back is left pain-free and functioning normally there’s a good chance that the spaces will open up again.

“Traditional kissing spines surgery is about the most invasive surgery going,” he adds. “ISLD is at the other end of the spectrum. There’s a risk that it might not completely resolve the problem, but it’s minimally invasive with a low complication rate and a moderate cost.”

Claiming equivalent success rates to traditional surgery, Richard stresses that post-operative rehab is equally critical — getting everything right from physiotherapy to saddle fit. And he acknowledges the difficulties involved in judging the efficacy of any kissing spines surgery.

“Horses that have kissing spines and nothing else in the way of lameness are few and far between, so it’s hard to evaluate the procedure alone,” he says.

“But you can’t quantify the ‘character transplant’ that many of my cases seem to experience after surgery.”

Similar comments have been made after both types of surgery, so the jury is still out. A detailed comparative study would be wonderful — but difficult.

Case study: Traditional kissing spines surgery

Eventer Billy Buzz (below) had traditional kissing spines surgery as a five-year-old.

“She loved her work, so when she started napping we thought it was a bit odd,” says Isabel Dijvanovic, whose mare, now nine, was diagnosed with the condition and operated on by Svend Kold to remove one spinous process.

“She had a 10cm incision that quickly started to heal. I got back on her eight weeks to the day after surgery and we were competing midway through the next season.

“She has never had a problem with her back since,” adds Isabel, who went on to compete Buzz at last year’s young rider European championships. The mare is now winning at intermediate level with Chris King.

Case study: New kissing spines treatment

Irish sports horse mare Molly’s unwillingness to accept the bit was causing her owner, Margaret Little, some concern. When possible causes such as teeth and tack problems had been ruled out, Margaret spoke to her vet, Richard Coomer.

“When Molly was diagnosed with kissing spines, Richard suggested the new procedure,” says Margaret, whose 15-year-old mare was treated with ISLD in 2010. “She now accepts the bit more happily and has been scoring well in unaffiliated dressage.”

Earlier this year, Margaret’s part-Irish draft mare Polly was also operated on by Richard.

“A few weeks after the op, Richard was amazed at how much they [the processes] had opened up,” explains Margaret. “The incisions healed quickly and the scars have almost disappeared. She’s doing wonderfully — her canter issues have been solved and last week she won a hunter class.”

This article first appeared in Horse & Hound’s 19 September issue.