Tuberculous Spondylitis

Incidence

Tuberculous spondylitis is still a problem in 3rd World. Until the recent AIDS epidemic it was a rare disease in the first world. It affects males more often than females. The most commonly affected level is L1.

Aetiology

Mycobacterium tuberculosis

Pathology/ Pathophysiology

• usually a secondary infection – primary lesion in lung, GIT or GUT;
• rarely spine involved in direct spread from other structures
• The infection begins in the paradiscal vertebra. Infection tends to spread across the periphery of the disc to involve the metaphyses of the vertebrae above and below. It is typical to see more than one vertebra involved ( av ~ 3)

• The anterior and posterior longitudinal ligaments and periosteum become compromised and arteries thrombose. The bone is destroyed secondary to osteonecrosis and as a direct result from the granulomatous process. The disc, being relatively avascular is relatively spared and destroyed late in the disease

• Disease progression:
  • granuloma formation, pus production +/- abscess formation
  • bone loss, death +/- collapse
  • neurological involvement may be seen in active disease or healed disease
    • Active disease:
      • pressure from pus, granuloma, bony sequestra, disc material, bony collapse
      • Can get TB meningitis or meningomyelitis
    • Healed disease: due to internal bony bridge or fibrous tissue constriction

Clinically

• Dependent on stage of disease;
  • In general:
    • fever, malaise, weight loss and evidence of TB elsewhere 
  • Local:
    • pain at rest, worse with motion
    • muscle spasm
    • deformity
    • sinus  tract
  • Neurologic symptoms

• Investigations
  • Blood tests:WBC, ESR, CRP
  • Mantoux:
  • Radiology:
    • CXR
    • Spine: plain films, CT, MRI
  • Biopsy: Z-N staining of material; high yield in active disease, poorer in healed disease

Differential Diagnosis

• other infection
• neoplasia
• Healed TB can resemble congenital fusions

Treatment

• Triple therapy:
  • Streptomycin: initial 2-3 mths
  • Isoniazid: 9 mths
  • Rifampicin: 9 mths

• Commence antibiotics ~ 1 wk prior to surgery
• Indications for nonsurgical treatment alone are patients with early disease with minimal bone involvement and medical contraindications to operation
• Surgery is indicated in all others – especially in the paraplegia of active disease
• Surgery – recommended is the Hong-Kong operation- consists of excision of the disease focus and strut grafting
  • advantages:
    • adequate material for analysis
    • prevention of progression of abscess
    • relieve pressure on neural tissue
    • graft under compression – fusion almost sure- thus late kyphosis prevented

Prognosis

• The is a good prognosis for recovery in neurological compromise of active disease
• poor prognosis in paraplegia of healed disease probably due to causes (ie fibrosis constricting cord, or impingement of cord on hard bony bridge arising from multilevel disease)
• Severe kyphotic deformity may result if a larger number of levels are involved
  
  
  

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