Primary Causes of Thoracic Spondylosis
Thoracic spondylosis is primarily caused by age-related degenerative changes, including disc degeneration, facet joint hypertrophy, and ligamentum flavum ossification, with risk factors including advancing age, genetic predisposition, and mechanical stress. 1
Pathophysiology and Anatomical Considerations
Thoracic spondylosis is a degenerative condition affecting the thoracic spine (T1-T12) that is less common than cervical or lumbar spondylosis due to:
- Additional weight-bearing support from the ribs
- Limited mobility in the thoracic spine
- Smaller disc size compared to cervical/lumbar regions 1
The condition most commonly affects the lower thoracic spine (T7-T12), with the T10-T12 levels showing particular predilection for degenerative changes 2.
Primary Causes
1. Age-Related Degeneration
- Natural wear and tear of spinal components
- Progressive disc dehydration and height loss
- Facet joint cartilage deterioration
- Ligamentum flavum hypertrophy and ossification 1, 2
2. Genetic Factors
- HLA-B27 association (particularly in ankylosing spondylitis) 3
- Inherited connective tissue disorders:
3. Inflammatory Conditions
- Ankylosing spondylitis (most common inflammatory cause) 3
- Other spondyloarthropathies:
- Psoriatic spondyloarthritis
- Reactive arthritis
- Enteropathic spondyloarthritis 3
4. Mechanical Factors
- Repetitive microtrauma
- Occupational stressors (heavy lifting, vibration exposure)
- Postural abnormalities (kyphosis)
- Spinal instability 4
5. Post-Traumatic Changes
- Previous thoracic spine injuries
- Vertebral fractures leading to accelerated degeneration 4
6. Metabolic Disorders
- Osteoporosis (particularly in the elderly)
- Chronic steroid use leading to vertebral body weakening 3
Clinical Relevance and Presentation
Thoracic spondylosis presents with:
- Thoracic back pain (76% of symptomatic cases)
- Potential neurological symptoms in advanced cases:
- Motor/sensory deficits
- Spasticity/hyperreflexia
- Positive Babinski sign
- Bladder dysfunction 1
Diagnostic Considerations
Imaging is not typically indicated for acute thoracic back pain without neurological symptoms or red flags, but should be considered when:
- Pain persists despite 6 weeks of conservative management
- Neurological symptoms develop
- Significant functional decline occurs
- Red flags are present
- History of osteoporosis or chronic steroid use 1
Special Considerations
Concurrent Conditions
Thoracic spondylosis often coexists with lumbar spondylosis, which can complicate diagnosis. Patients may be initially misdiagnosed with only lumbar pathology when thoracic involvement is present 4.
Rare Manifestations
In some cases, thoracic spondylosis can lead to:
- Degenerative spondylolisthesis (rare in thoracic spine)
- Facet joint effusions visible on MRI
- Myelopathy due to spinal canal stenosis 4
Understanding these causes is essential for proper diagnosis and management of thoracic spondylosis, which requires a different approach than cervical or lumbar degenerative disease due to the unique biomechanical properties of the thoracic spine.