Red Light Therapy for Kissing Spine in Horses: Why Even Surgery Doesn't Cure It
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The vet holds up the radiograph and points. There they are — the bony processes along your horse's spine, sitting close together, some of them touching. Kissing spine. And in that moment it feels like everything has been explained: the girthiness, the hollow back, the refusals.
Here's what we're going to be honest about, because it changes how you should think about every treatment decision that follows — including whether red light therapy has any place in this at all.
That X-ray doesn't prove your horse is in pain. And even the surgery for kissing spine doesn't cure it.
The Short Answer
Red light therapy cannot treat kissing spine. Kissing spine is a bony problem — the gap between two spinous processes has narrowed to less than 4mm and they contact each other. No light device changes bone spacing.
But here's the more useful framing: even the surgery doesn't cure it. The ligament snip doesn't fix the condition — it minimises symptoms so the back can move comfortably during rehabilitation. If cutting a ligament only buys a horse the chance to rehab, a pad on the back isn't fixing anything either. Rehabilitation is the treatment. Everything else — injections, shockwave, surgery, and yes, supportive therapies — exists to make the rehab possible.
What Kissing Spine Actually Is
The proper name is overriding or impinging dorsal spinous processes (ORDSP). The definition is precise: narrowing of the space between two thoracolumbar spinous processes to less than 4mm, so the bony tips sit too close and may touch — "kiss."
It's mainly detected between T14 and L1 — the middle to end of the thoracic spine, directly under where the saddle sits. That close contact can cause bony changes to the vertebrae and chronic inflammation.
It's most often diagnosed in teenage horses, though radiographic changes turn up in younger and older ones too. Any breed can be affected, with Thoroughbreds and warmblood types overrepresented. And on cause: it's unknown. Training, muscle strength, saddle fit and genetics are all hypothesised, and most likely several factors are in play in any individual horse.
The Most Important Fact: The X-ray Doesn't Tell You If It Hurts
⚠️ Plenty of comfortable, working horses have kissing spine
Overriding dorsal spinous processes are described in asymptomatic ridden horses as well as in horses with thoracolumbar pain. Read that again. Horses going happily under saddle, with no back pain at all, can show the same radiographic finding your horse just showed.
It gets more pointed: radiographic and scintigraphic evidence for ORDSP is not necessarily correlated with clinical signs of thoracolumbar pain. The X-ray and the bone scan do not reliably tell you whether the horse hurts.
And so, although the condition is readily identified on lateral radiographs, recognising which cases are clinically significant remains challenging. Which is why the profession describes kissing spine as easy to diagnose, complicated to treat.
Why this matters at a prepurchase exam
Lateral spinal radiographs are increasingly included in routine prepurchase examinations, specifically to tell buyers about this condition. That's useful information — but it is information, not a verdict.
Clinical signs range all the way from asymptomatic radiographic changes to a horse who is unrideable or uncomfortable with even light pressure over the affected areas. A finding on a film sits somewhere on that spectrum, and only the whole clinical picture — assessed by your vet — tells you where.
The Signs — Frustratingly Variable
Clinical signs are often non-specific, which is a recurring theme in equine back problems:
- Loss of performance — the most common complaint, and rarely dramatic.
- Pain on palpation over the affected area.
- Subtle gait alterations — not obvious lameness.
- Behavioural changes — the girthiness, the reluctance, the "he's just being difficult."
- Anywhere on the spectrum — from nothing at all, to a horse uncomfortable with even light pressure on his back.
If your horse is telling you something is wrong with his back, our guide to red light therapy and horse back pain covers why back signs are usually symptoms of something that needs identifying.
Diagnosis: Why the Picture Isn't Enough
Since the radiograph can't tell you whether it hurts, vets have to establish whether the finding is clinically significant — typically by combining imaging with local infiltration of anaesthetic agents over the affected spaces and seeing whether the horse changes.
⭐ And first — a full lameness evaluation
A full lameness evaluation is key, because back pain can be initiated or exacerbated by lameness — and treatment of the primary lameness will be pivotal to improving the kissing spine pain in those cases.
This is the trap. A horse compensating for a hock, a stifle, or a foot will change how he carries his back. Treat the back and ignore the leg, and you're chasing the shadow instead of the thing casting it.
What Actually Treats It
Most specialists start conservatively. In an international survey of equine orthopaedic specialists, 71% preferred conservative management and recommended surgery only for horses that didn't respond to it.
| Approach | What it involves |
|---|---|
| Conservative (first line) | The most popular combination is local injection paired with controlled exercise. Steroid injections and/or shockwave, plus rehabilitation using tolerated exercise after a progressive warm-up. |
| Manual therapy | Considered by 42% of European and 25% of American specialists — regional practice varies. |
| ISLD ("ligament snip") | Interspinous ligament desmotomy — cutting the ligament between affected processes. Done standing under sedation and local anaesthesia. High long-term success rate. |
| Ostectomy (bone shaving) | Removing parts of the spinous processes to widen the space. More invasive and costly; 3–6 months recovery and rehabilitation. |
⚠️ The thing nobody puts in the brochure
ISLD does not cure kissing spine. It minimises symptoms and allows the back to move comfortably during rehabilitation. And if the horse isn't rehabbed properly afterwards, some experience recurrence of kissing spine or develop it in other areas.
Sit with that. A surgeon divides a ligament with a chisel — and the honest description of what that achieves is "it buys comfort so the rehab can happen." Not a cure. A window.
If that's true of surgery, it's emphatically true of a light pad.
Rehabilitation Is the Treatment
This is the part that decides your horse's outcome, and it happens at home over months.
Regardless of the treatment plan selected by the veterinarian and owner, continued rehabilitation at home is key to long-term success. Maintaining strong musculature and spinal flexibility will be key to long-term treatment success.
That 80–90% figure is genuinely encouraging — overall prognosis is excellent with appropriate therapy and rehabilitation. But notice the qualifier that carries the whole sentence: with appropriate rehabilitation.
The work is building and maintaining the musculature that supports the back — which is exactly why understanding what actually builds your horse's topline matters here. Anti-inflammatory treatment reduces pain and stiffness between the processes so that you can exercise your horse and help him build topline. That's the sequence: relieve, then rebuild.
So Where Does Red Light Therapy Fit?
In the same modest place everything except the rehab occupies — and only with your vet's agreement.
It does not change bone. The gap between two spinous processes is a structural fact; light does not widen it. It is not a treatment for kissing spine, and any claim otherwise is fiction.
What's plausible is narrower: the musculature over the back is within reach of light, and if your vet is running a rehabilitation programme and believes supporting comfort in that superficial muscle helps your horse do the work, that's their judgement to make about your case.
The three lines not to cross
Don't let it substitute for the lameness workup. If a hock is driving the back pain, treating the back is chasing shadows. Don't let an X-ray finding plus a device become your plan. The film doesn't prove the pain, and the device doesn't treat the bone. Don't let it replace the rehab. Even surgery doesn't cure this — the rebuilding does.
A note on prepurchase exams: if radiographs on a horse you're considering show ORDSP, that is not automatically a reason to walk away — asymptomatic horses have these changes too. It's a reason to talk to your vet about the whole horse. Equally, it isn't nothing. Get proper advice, not internet advice.
Conclusion: The Film Isn't the Diagnosis, and the Snip Isn't the Cure
Kissing spine is easy to diagnose and complicated to treat — and both halves of that phrase deserve your attention. Easy to see on a film, yes. But asymptomatic ridden horses show the same finding, and the radiographic and scintigraphic evidence isn't necessarily correlated with pain. The picture is information, not a verdict.
And on the other side: even the surgery doesn't cure it. The ligament snip buys comfort so rehabilitation can happen; skip the rehab and horses relapse or develop it elsewhere. The rehabilitation is the treatment — strong musculature, spinal flexibility, months of correct work — and it's why 80–90% of horses return to some degree of performance when it's done properly.
Red light therapy doesn't change bone and doesn't shortcut any of that. If your vet has the diagnosis, has ruled out the lameness underneath, and has a rehab plan running, ask them whether comfort support in the back musculature has a role — and the PbmEquine equine range will still be here for that modest job. But the horse gets better because of the work. Not because of the light.
Frequently Asked Questions
Can red light therapy treat kissing spine in horses?
No. Kissing spine, properly called overriding or impinging dorsal spinous processes, is a bony problem — the space between two spinous processes has narrowed to less than 4mm, and they contact each other. No light device changes bone spacing. Here is the most useful way to think about it: even the surgery does not cure kissing spine. Interspinous ligament desmotomy, the so-called ligament snip, has a high long-term success rate, but it does not cure the condition — it minimises symptoms so the back can move comfortably during rehabilitation, and horses that are not rehabbed properly can relapse or develop the problem at other sites. If cutting a ligament under sedation only buys a horse the chance to rehabilitate, a pad on the back certainly is not fixing anything. Rehabilitation is the treatment. Red light therapy may, at most, support comfort in the superficial back musculature within a vet-directed rehabilitation plan — never as a substitute for one.
What is kissing spine in horses?
Kissing spine — overriding or impinging dorsal spinous processes, abbreviated ORDSP — is defined as narrowing of the space between two thoracolumbar spinous processes to less than 4mm, so that the bony tips sit too close and may touch. It is mainly detected between T14 and L1, which is the middle to end of the thoracic spine, directly under where the saddle sits. That close contact can cause bony changes to the vertebrae and chronic inflammation. It is most often diagnosed in teenage horses, though radiographic changes appear in younger and older ones too, and any breed can be affected, with Thoroughbreds and warmblood types overrepresented. The cause is unknown: training, muscle strength, saddle fit and genetic factors are all hypothesised, and most likely several factors are at play in any individual horse.
Does kissing spine on an X-ray mean my horse is in pain?
No — and this is the single most misunderstood thing about the condition. Overriding dorsal spinous processes are described in asymptomatic ridden horses as well as in horses with thoracolumbar pain, and radiographic and scintigraphic evidence of ORDSP is not necessarily correlated with clinical signs of back pain. In other words, the picture does not tell you whether it hurts. Although the condition is readily identified on lateral radiographs, recognising which cases are clinically significant remains genuinely challenging — which is why it is often described as easy to diagnose but complicated to treat. Clinical signs range all the way from asymptomatic radiographic changes to a horse that is unrideable. This matters enormously at prepurchase examinations, where spinal radiographs are increasingly routine: a finding on a film is information, not a verdict, and it needs interpreting alongside the whole clinical picture by your vet.
What actually treats kissing spine in horses?
Conservative management first, for most specialists. In an international survey of equine orthopaedic specialists, 71% preferred conservative management and recommended surgery only for horses that did not respond to it, with the most popular combination being local injection paired with controlled exercise. Medical management typically involves local injections of steroids and/or shockwave therapy alongside rehabilitation using tolerated exercise after a progressive warm-up. Surgery is reserved for non-responders, and comes in two main forms: interspinous ligament desmotomy, which can be done standing under sedation and local anaesthesia, and partial resection of the spinous processes, which is more invasive and costly and needs three to six months of recovery and rehabilitation. Crucially, a full lameness evaluation matters first, because back pain can be initiated or worsened by limb lameness, and treating that primary lameness is pivotal.
What is the prognosis for a horse with kissing spine?
Better than most owners fear, but it depends almost entirely on the rehabilitation. Overall prognosis is described as excellent with appropriate therapy and rehabilitation, with 80 to 90% of horses returning to some degree of performance. The important qualifier is in that sentence: with appropriate rehabilitation. Regardless of which treatment plan the vet and owner choose, continued rehabilitation at home is key to long-term success, and maintaining strong musculature and spinal flexibility is what sustains it. Horses that are not rehabbed properly after surgery can experience recurrence or develop kissing spine at other sites, which tells you where the real work lies. Think of any intervention — injection, shockwave, surgery — as buying the horse a window of comfort in which the rebuilding can happen. The rebuilding is the treatment.
