What is Thoracic Spinal Stenosis?
Thoracic spinal stenosis refers to narrowing of the spinal canal in the mid-back region, resulting in compression of the thoracic spinal cord. The narrowing may be acquired — developing over time due to degenerative changes, OLF, disc herniation, or thickened ligaments, or congenital, meaning the spinal canal was naturally narrow from birth.
Congenital thoracic stenosis is a developmental condition in which the vertebral canal does not develop to its normal dimensions. Patients with congenital stenosis may remain asymptomatic for years, but have significantly reduced reserve — even mild degenerative changes that would be inconsequential in a normal-sized canal can cause significant cord compression and myelopathy.
Who Gets It and Why?
- Congenital – developmental narrowing of the thoracic canal, sometimes associated with other skeletal dysplasias
- Degenerative – thickening of ligaments, disc degeneration, facet joint hypertrophy, and OLF collectively narrowing the canal
- Post-traumatic – deformity or bony overgrowth following spinal fractures
- Inflammatory – conditions such as ankylosing spondylitis
What Does It Feel Like?
Symptoms are those of thoracic myelopathy:
- Progressive bilateral leg weakness and stiffness
- Difficulty walking, particularly uphill or on uneven terrain
- Sensory disturbance in the legs – numbness, tingling, or a sensation of wearing tight stockings
- Bladder urgency or dysfunction
- Back pain – variable; may be mild even with severe stenosis
In congenital stenosis, patients may notice that symptoms fluctuate – temporarily worsening after physical activity – before eventually becoming persistent as the condition progresses.
How Is It Diagnosed?
- MRI thoracic spine – demonstrates the extent of canal narrowing and degree of cord compression
- CT scan – essential for surgical planning, particularly in congenital cases where bony anatomy needs precise characterisation
- Dynamic studies may help identify positional cord compression
How Is It Treated?
Congenital and acquired thoracic stenosis causing myelopathy requires surgical decompression. Non-surgical measures can help manage pain but will not halt neurological progression once significant cord compression is established.
Posterior laminectomy, with or without fusion depending on stability, is the principal surgical approach. The extent of decompression required is guided by the length of stenosis on imaging. In congenital cases, careful pre-operative planning is essential to ensure adequate decompression without destabilising the spine.
Outcomes are favourable when surgery is performed before irreversible cord injury. Regular neurological monitoring is important in patients with known congenital stenosis even before symptoms become severe.
Self-Check at Home
The Positional Symptom Check: Thoracic stenosis often causes symptoms that are influenced by posture:
- Do your leg symptoms worsen when you stand upright or walk, and improve when you sit and lean forward?
- Do you find it more comfortable to walk slightly bent forward rather than fully upright?
This positional pattern, similar to lumbar stenosis, suggests dynamic cord compression from thoracic stenosis.
The Progressive Disability Timeline: Think back over the past 6 to 12 months:
- Are you walking shorter distances than you used to?
- Have you stopped activities (climbing stairs, walking on uneven ground) that you previously managed without difficulty?
- Has anyone commented on a change in the way you walk?
Progressive functional decline in walking ability without a clear musculoskeletal explanation (knee or hip arthritis, cardiac or respiratory cause) should prompt thoracic spine evaluation.
Motion-Preserving Considerations
Decompressive laminectomy without fusion is the preferred approach for thoracic stenosis when spinal stability is maintained. Fusion adds surgical complexity, recovery time, and permanently reduces thoracic mobility, and is therefore reserved for cases where instability is documented.
