Where does tuberculosis (TB) of the spine typically affect?

Tuberculosis of the Spine Typically Affects the Lower Thoracic and Upper Lumbar Regions

Tuberculosis of the spine most commonly affects the lower thoracic and thoracolumbar regions, accounting for approximately 50% of all musculoskeletal tuberculosis cases. 1

Anatomical Distribution of Spinal TB

• Primary location: Lower thoracic and upper lumbar vertebrae 1, 2
• Secondary locations:
  • Mid-thoracic region (T6-T10) 3
  • Upper thoracic region (T3-T5) 3
  • Lower lumbar region (L3-L5) 3

Pathophysiology and Characteristics

Spinal TB (also known as Pott's disease) typically involves:

• Vertebral body involvement: The infection primarily affects the anterior vertebral body 4
• Multiple vertebrae: Often involves 2-4 contiguous vertebral bodies 3
• Intervertebral disc: The disease typically destroys the intervertebral disc due to the shared segmental arterial blood supply 4
• Spread mechanism: Usually occurs via hematogenous spread from a primary focus (often pulmonary) 4

Radiological Patterns

Two distinct patterns can be observed in spinal TB 2:

1. Classic pattern (most common):

   • Destruction of two or more contiguous vertebrae
   • Destruction of opposed end plates
   • Intervertebral disc infection
   • Paraspinal abscess formation

2. Atypical pattern (increasing in frequency):

   • Spondylitis without disc involvement
   • More focal vertebral body involvement

Clinical Manifestations

The hallmarks of spinal TB include 1, 5:

• Progressive vertebral collapse
• Kyphotic deformity (gibbus)
• Neurological deficits (including paraplegia in advanced cases)
• Back pain
• Palpable paraspinal mass in some cases

Treatment Considerations

• Medical treatment: Six-month regimen of rifampicin and isoniazid, supplemented with pyrazinamide and ethambutol for the first two months 6
• Surgical indications: Reserved for patients with spinal instability, neurological impairment, or severe deformity 1, 4
• Surgical approach: Debridement, deformity correction, and stable fusion are the cornerstones of surgical treatment 1

Important Considerations

• Early diagnosis and treatment are crucial to prevent severe neurological complications and spinal deformities 5
• The diagnosis may be challenging as clinical findings can be non-specific and radiological features may mimic other conditions 2
• Definitive diagnosis requires tissue confirmation through culture, histology, or PCR 1
• Drug resistance is an emerging challenge in the management of spinal TB 1

Understanding the predilection of TB for the lower thoracic and upper lumbar spine is essential for early diagnosis and appropriate management to prevent the potentially devastating neurological complications associated with this disease.