Spondylosis in dogs – symptoms, treatment and spinal screening

Overview

Bone spurs and bridges are X-ray findings

Spondylotic bone growth starts near the attachment of the disc's outer ring to the vertebra. A lesion may be a small spur or a bony bridge across a disc space. Growth usually extends along the lower and lateral vertebral surfaces. It therefore rarely affects the spinal cord.

Several spinal sites can be affected at the same time. Common regions include the lower thoracic spine, lumbar spine and lumbosacral region. Even severe X-ray changes may cause no signs. Imaging findings are therefore interpreted alongside function and examination findings.

Spondylosis becomes more common with age. Changes have been estimated to occur in 25–70% of dogs at around 9 years of age. This describes the frequency of bone changes, rather than an equivalent proportion of painful spinal disease.

Causes

Spinal movement and degeneration of supporting tissues

Intervertebral discs act as shock absorbers between vertebrae. Surrounding joints and ligaments allow back movement and protect the spinal cord. Disc damage or degeneration can increase instability between vertebrae.

Spondylosis involves damage to fibres in the disc's outer ring and stretching of the longitudinal ligament. Increased stress at the vertebral attachment triggers bone formation. Bone spurs can therefore support a previously less stable vertebral segment.

Hereditary and age-related changes

An inherited form occurring in young dogs is called primary spondylosis. The form developing with age is called secondary spondylosis. Not every spondylotic change is therefore hereditary.

Spondylosis itself is a non-inflammatory degenerative change. Vertebral injury, a congenital structural abnormality or infection between vertebrae can also cause spurs in an unstable spine. Their cause and treatment may differ from ordinary spondylosis.

Risk factors

Spondylosis occurs particularly in middle-aged and older dogs. It is generally uncommon before 2 years of age. An inherited predisposition has, however, been identified in Boxers. Changes can appear while they are young.

Predisposition has also been described in German Shepherd Dogs and Flat-Coated Retrievers. The disease is nevertheless not confined to large breeds. Age, repeated minor strain injuries, major trauma and inherited predisposition can contribute to development.

Age-related changes have been described as starting in most dogs by around 10 years of age at the latest. Previous spinal surgery can also be associated with bone spur formation around a vertebral segment.

Typical symptoms

Many dogs with spondylosis live without visible signs. In a dog with signs, you may notice:

• A stiffer back with restricted movement.
• Tenderness when the back is touched or moving away from a hand.
• Lameness or movement different from before.
• Difficulty lying down or getting up.
• Avoidance of jumping.
• Whining or vocalising when the back is touched.

Chronic pain may appear as gradual changes in movement, mood or willingness to participate. A dog can continue playing despite pain. A lack of complaints alone therefore does not establish an absence of signs.

Pain may also involve restless sleep or more frequently interrupted rest.

Complications and consequences

Stiffness and nerve root irritation

A bony bridge beneath a vertebra can stiffen the back and increase stress on neighbouring segments. A developing spur can fracture or rub against another spur and cause local pain. Local signs sometimes improve once ossification forms a complete bridge.

Rare lateral bone growth can compress a nerve root. Severe signs, such as paralysis or loss of continence, may then occur. These require urgent assessment regardless of their precise cause.

Untreated chronic pain can sustain a cycle of less movement, weaker muscles and increasing pain. With sensitisation of the pain system, even ordinary touch may feel painful.

Diagnosis at the vet

Clinical examination and imaging

Spondylosis is usually diagnosed on spinal X-rays. It may be found during imaging for a completely different reason. Ordinary X-rays do not show discs and other soft tissues in sufficient detail.

Neurological examination assesses movement, proprioception, reflexes and pain sensation. Further investigations are selected according to the examination. CT or MRI may be needed particularly for suspected nerve root compression. A spur's appearance does not necessarily distinguish ordinary spondylosis from changes due to inflammatory instability.

Under one official screening scheme, imaging is performed under veterinary supervision with sedation to achieve correct positioning. The vet submits images to the scheme for assessment. In addition to lateral views, a ventrodorsal lumbosacral image or hip image is needed for a spondylosis report.

An example of SP grading

This scheme's spondylosis assessment uses lateral thoracic and lumbar spinal images. The minimum imaging age for an official report is 24 months. At least 12 months must pass after the previous report before a new one. Diagnostic imaging of an ill dog and breeding screening serve different purposes.

• SP0 means no spondylotic changes are found.
• SP1 is mild: spurs under 3 millimetres may affect up to 4 disc spaces, or spurs over 3 millimetres up to 3 disc spaces. SP1 can also include a bone island at up to 2 disc spaces.
• SP2 means complete or incomplete bridges or large islands at up to 2 disc spaces.
• SP3 means bridges or large islands at 3–7 disc spaces.
• SP4 means more severe changes than these.

Assessment covers thoracic vertebrae 1–13, lumbar vertebrae 1–7 and the sacrum. Age adjustment disregards 1 bridge in a dog aged 5–7 years. It disregards 2 bridges at 8 years or older. An older dog nevertheless cannot receive SP0 if a bony bridge is present.

A dog operated on for the spinal change being screened receives an operated designation for that change. Under the scheme, this is treated as the most severe grade for breeding. Previous spinal surgery is therefore reported at imaging.

Extensive ossification may be another disease

DISH is a separate disease involving ossification at the bony attachments of ligaments, tendons or joint capsules. Its radiographic criteria include continuous ossification across at least 4 consecutive vertebrae. Disc space width remains relatively normal. The criteria also require that the small facet joints between vertebrae are not fused. The disease can also cause no signs or be associated with back pain and stiffness. Naming the finding therefore clarifies the type of spinal bone growth involved.

Treatment

An incidental finding and pain management

Spondylosis without signs does not usually need treatment. A painful dog's treatment plan follows signs and examination findings. NSAIDs or other pain medicines can relieve signs. Medication is selected by your vet.

Physical physiotherapy methods may include heat or cold treatments chosen for the dog's situation. Manual treatment may involve soft tissue techniques and joint mobilisation, supporting movement by hand. Treatment goals therefore relate to function and quality of life, rather than X-ray appearance alone.

Rehabilitation and weight management

Physiotherapy, reducing excess weight and controlled exercise can help a dog with signs. Adjusting everyday activity demands also forms part of chronic pain care. Older dogs can receive pain treatment as well. Age is therefore not a reason to leave clearly deteriorating movement uninvestigated.

Initial physiotherapy assessment identifies movement restrictions, muscle wasting and any reduced limb weight bearing. Goals may include increasing muscle strength or range of movement. The rehabilitation plan records a timetable and suitable therapies.

Active exercise may include an individual home programme or underwater treadmill work. Some veterinary physiotherapy services require a referral or veterinary consent for an ill dog's treatment. Effectiveness is reassessed during rehabilitation. Goals are therefore reviewed according to actual progress.

Individually fitted support harnesses or lifting slings can assist movement where needed. Owner guidance and planning home exercises form part of physiotherapy. Short- and long-term rehabilitation goals are developed with the owner.

When is surgery considered?

Surgery is rarely considered where bone spurs cause demonstrated spinal cord compression. A bony bridge alone in a dog without signs is not such an indication. Further investigations are particularly necessary if a dog has signs of nerve damage or pain. Surgical planning therefore targets an identified cause of signs.

Living with spondylosis

Many dogs live well with spondylosis despite some restricted spinal movement. A change causing no signs may remain unnoticed for life. The individual outlook depends on investigation results and treatment response.

Prevention

Breeding choices can influence the occurrence of hereditary spondylosis. Under the screening scheme described above, registration rules exclude an SP4 dog from breeding. Those guidelines also recommend against breeding from a dog with spondylosis signs even with a milder grade.

Under those guidelines, an SP0 partner is recommended for an asymptomatic SP1–SP3 dog. Spinal screening is recommended for offspring of such matings. Some Boxer breeding programmes can use a spondylosis breeding index to assist selection. A back found free of signs at an older age provides valuable breeding information.

The screening targets primary spondylosis that can be reduced through breeding. Direct comparison of different-aged dogs is difficult because the contribution of ageing changes varies.

Important for dog owners

Monitor everyday function

Record when movement changed and whether the change has increased. Monitor shorter walks, lagging behind, stair avoidance and getting into a car. Slow rising, repeated position changes and restless sleep are also useful observations. Record them during treatment as well so that progress can be compared with the starting point.

Some dogs conceal pain by continuing ordinary activities. A new change in movement, appetite or response to touch warrants veterinary assessment. Do not give human pain medicines without veterinary instructions.

SP0 means only that spondylotic changes are absent, rather than every spinal disease. New back signs are therefore investigated even in a dog previously screened as clear.

Frequently asked questions

Is spondylosis always painful?

A dog can be completely free of signs even with severe X-ray changes. Some dogs nevertheless develop stiffness or back pain. Examination assesses the source of pain. Spur numbers therefore do not directly establish how painful an individual dog is or what restricts movement.

Can spondylosis cause paralysis?

Ordinary lower and lateral bone spurs rarely affect the spinal cord. Rare nerve root compression can nevertheless be associated with serious signs. Sudden paralysis or loss of continence requires prompt assessment. The true cause is investigated even with an existing spondylosis diagnosis.

What do SP0 and SP4 mean?

In the scheme described above, SP0 means a back clear of spondylosis. SP4 is the most severe grade. The grading describes X-ray changes. SP0 does not exclude other spinal diseases. SP4 leads to breeding exclusion under that scheme's registration rules. Signs and treatment needs are assessed separately.

At what age is spondylosis screening performed?

The minimum age for an official spondylosis report under that scheme is 24 months. New reports must be at least 12 months apart. This concerns screening. Investigation needs in a dog with signs are assessed separately, and nerve damage signs may require imaging beyond X-rays.

Does spondylosis always need medication or surgery?

Spondylosis without signs usually needs no treatment. A painful dog may be prescribed an NSAID or another pain medicine. Physiotherapy and controlled exercise may form part of treatment. Surgery is rarely indicated where bone growth is shown to compress nervous tissue.