Kissing Spines in Horses: Causes, Symptoms, and Modern Treatment Options

Kissing spines, or overriding dorsal spinous processes (ODSP), are one of the most common causes of chronic back pain and reduced performance in horses, particularly Warmbloods, Thoroughbreds and Quarterhorses. With new advances in diagnostics, biomechanics, and rehabilitation research, veterinarians and owners now have more options than ever to successfully manage this complex condition.

In this detailed guide, we’ll explore the anatomy and biomechanics of the equine spine, clinical signs, the influence of saddle

fit, and the latest evidence for both surgical and non-surgical treatments — including recent studies on chiropractic and acupuncture for back pain management.

Understanding the Anatomy of the Equine Spine

The equine spine is divided into five main regions: cervical, thoracic, lumbar, sacral, and coccygeal. The thoracic (T1–T18) and lumbar (L1–L6) vertebrae are most often affected in kissing spines. Each vertebra has a dorsal spinous process (DSP) projecting upward beneath the horse’s topline.

Normally, the DSPs are separated by soft tissues such as the interspinous and supraspinous ligaments. However, when these bony processes come too close together (less than 4 mm) or overlap, they “kiss,” causing inflammation, pain, and bony remodeling. The area between T13 and T18 (especially T15), directly beneath the saddle, is most commonly affected because of its anatomical narrowing and high mechanical stress. Up to 92% of horses have evidence of kissing spines on radiographs, however, not all exhibit clinical signs.

Biomechanics: Why Kissing Spines Develop

The horse’s thoracolumbar spine acts as a bridge between the forehand and hindquarters, transferring propulsive forces through lateroflexion, flexion-extension and axial rotation, all while supporting the rider’s weight. During collection and engagement, the spine flexes and the spaces between DSPs widen. When a horse hollows its back — due to pain, weakness, or poor saddle fit — those spaces narrow, increasing the risk of impingement.

Research shows that T13–T18 experiences the greatest dynamic load under saddle as it is the most flexible portion of the thoracolumbar spine - and this is considered to be a contributing factor. Poor core strength, uneven rider balance, or ill-fitting saddles further increase mechanical strain in this region. Thus, kissing spines often result from both anatomical predisposition and biomechanical dysfunction, although a genetic component, nutritional imbalances and rapid growth may also be contributory.

Recognizing the Signs of Kissing Spines in Horses

Kissing spines often present subtly as performance or behavioral issues. Common symptoms include:

• Resistance to going forward or collecting

• Shortened stride or stiffness

• Difficulty with transitions or lateral work

• Bucking, tail swishing, or head tossing

Palpation frequently reveals tenderness over the thoracolumbar region and muscle atrophy along the topline. However, some horses show radiographic evidence of DSP impingement without pain, making clinical correlation essential. Osteoarthritis of articular process joints and spondylosis may also be present, particularly in fully developed horses.

The Role of Saddle Fit

Poor saddle fit is both a contributing factor and a confounding variable in kissing spine cases. Saddles that are too narrow, long, or unbalanced place concentrated pressure directly over the caudal thoracic spine. This encourages a hollow back and narrows the interspinous space.

A 2023 review found that over two-thirds of horses with kissing spines improved when saddle fit was corrected, even before medical or surgical interventions. A professional saddle fitting should therefore be one of the first steps in any back pain evaluation.

Non-Surgical and Conservative Treatment Options

For horses with mild or moderate lesions, conservative management focuses on pain relief, restoring spinal mobility, and improving biomechanics.

Medical and Physical Therapies

Initial pain control often includes non-steroidal anti-inflammatory drugs (NSAIDs), mesotherapy, bisphosphonates or targeted corticosteroid injections between the affected DSPs.

Extracorporeal shockwave therapy (ESWT) has been shown to enhance comfort and flexibility, particularly when paired with physiotherapy exercises.

Class IV laser therapy (High-Intensity Laser Therapy, HILT) is another emerging option. In a 2024 study on Thoroughbreds with back pain, HILT significantly reduced pain sensitivity and improved local circulation, suggesting a role in reducing muscular tension and inflammation.

Chiropractic Therapy (Improving Spinal Biomechanics)

Chiropractic treatment involves manual adjustments to the spine and pelvis to restore normal joint motion, improve symmetry, and optimize neuromuscular function. In horses with kissing spines, this therapy aims to enhance spinal mobility and reduce compensatory strain that can exacerbate DSP impingement.

A controlled study of Warmbloods with back pain demonstrated increased range of motion (ROM) at thoracic and lumbar segments one hour and three weeks after chiropractic treatment. Another clinical trial found improvements in spinal pain and muscle hypertonicity following chiropractic adjustments.

By improving vertebral mobility, chiropractic therapy can help the horse develop a more rounded, engaged topline, reducing dynamic narrowing between spinous processes during work. However, these effects are typically short-lived unless supported by targeted exercise and postural conditioning.

When incorporated into a multimodal program alongside saddle-fit correction, pain management, and physiotherapy, chiropractic can play an important role in restoring healthy biomechanics and preventing recurrence.

Acupuncture for Pain Modulation and Muscle Relaxation

Acupuncture provides a drug-free, evidence-based approach to pain management and muscle relaxation. Stimulation of specific acupoints triggers neural responses that release endorphins, reduce inflammation, and enhance blood flow.

Recent research highlights the effectiveness of both electroacupuncture and laser acupuncture for thoracolumbar back pain, showing significant improvements in mechanical nociceptive thresholds and reduced muscle hypertonicity. Reviews of veterinary literature over the past two decades support acupuncture’s use for musculoskeletal pain, stiffness, and performance-related back issues.

In horses with kissing spines, acupuncture can reduce muscle guarding, improve flexibility, and enhance comfort, especially when combined with chiropractic care, conditioning exercises, and proper saddle fit. Evidence-based protocols recommend integrating acupuncture into a multimodal rehabilitation plan to maximize long-term outcomes.

Integrating Conservative Therapies

Optimal outcomes are achieved when therapies are combined strategically:

• Saddle fit correction to remove external pressure and restore balance.

• Acupuncture to alleviate muscular pain and reduce tension.

• Chiropractic to improve spinal motion and alignment.

• Laser or shockwave therapy to enhance circulation and healing.

• Targeted conditioning exercises (hill work, pole work, long and low) to strengthen core and back musculature.

This integrated approach addresses both symptoms and underlying biomechanics, promoting long-term comfort and preventing recurrence.

Surgical Treatment for Kissing Spines

When conservative treatment fails, surgery may be indicated. Two main surgical procedures are used:

1. Interspinous Ligament Desmotomy (ISLD): A standing, minimally invasive procedure that involves cutting the interspinous ligament to relieve tension and increase spacing between affected DSPs.

2. Partial Ostectomy (DSP Resection): A more invasive surgery that removes part of one or more DSPs to widen the gap and eliminate bony contact.

Studies report over 90% of horses return to some level of performance following ISLD, with about half regaining or exceeding previous competition levels. Prognosis is best when surgery is combined with structured rehabilitation, proper saddle fit, and management of any concurrent orthopedic issues.

When Surgery Doesn’t Work

While surgery has high success rates, not all horses make a full recovery. Common reasons for poor outcomes include inadequate rehabilitation, unresolved secondary lameness, and continued saddle-fit problems.

Some horses develop remodeling or impingement at adjacent spinous processes due to altered post-surgical biomechanics. Surveys suggest that while 70–90% of horses improve, only about one-third return to their previous level of athletic performance.

Final Thoughts

Kissing spines are not simply a bony problem — they are a biomechanical condition requiring a comprehensive, horse-centered approach. Effective management depends on accurate diagnosis, appropriate treatment selection, and long-term attention to spinal health, saddle fit, and rider balance.

Whether through surgical or conservative methods, the goal remains the same: to restore the horse’s ability to move freely, comfortably, and symmetrically. With modern therapies such as interspinous ligament desmotomy, chiropractic care, acupuncture, and laser therapy, many horses once deemed unrideable can now return to active, pain-free lives.