Spine TB

Question 1

what is the pathogenesis of spinal TB?

Answer 1

Mycobacterium tuberculosis

EARLY
- begins in metaphysis
- endplate sparing
- spreads under the ALL - gives sub ligamentous extension
- contiguous multi-level
- non-contiguous skip lesions - 15%
- Potts abscess - 50%
- preferentially affects the anterior elements

LATE
- severe kyphosis

Question 2

how many patients are typically affected by TB spine?

Answer 2

• 15% of TB is extrapulmonary
• 20% is osteoarticular
• 50% is spinal

Question 3

how will you assess the patient?

Answer 3

Clinical
- constitutional symptoms - malaise, temp, night sweats, weight loss
- risk factors - travel/ contact
- neurology/ back pain/ mobility
- current/ previous treatment
- neurology - direct from abscess/ granuloma and indirect from kyphosis
- kyphosis

biochemical
- inflammatory markers
- tuberculin skin test - low sens and spec
- CT guided biopsy
* PCR - 95% sensitivity - quicker and more sensitive than AFB culture (takes 10weeks)

Radiological
- X-rays - chest and spine
- MRI scan whole spine with gadolinium - bright on T2
CT - small changes/ biopsy

Question 4

what are the early and late radiographic TB changes

Answer 4

• Early - disc and endplate sparing
• late - kyphotic deformity

Question 5

what is a gibbus?

Answer 5

Anterior collapse of one or more vertebrae causing kyphosis

Question 6

what is the treatment of a gibbus?

Answer 6

For a severe Gibbus, you can only treat it with a vertebral column resection
- shortening procedure to straighten the spine
- risk of nerve injury and paralysis at that level

Question 7

which lesions are likely to progress?

Answer 7

Age
- children > adults
- children have progressive and agressive disease - children <7yrs
- 40% children progress due to growth spurt
- adults - once healed no progression

Level
- thoracolumbar > lumbosacral

no. Vertebrae
- >3 vertebrae involved

‘At risk signs’
- lateral translation
- retropulsion
- subluxation
- toppling

Question 8

what are the goals of treatment?

Answer 8

• eradicate the infection
• prevent complications - destabilisation/ pulmonary complications

Question 9

how would you manage a patient with spinal TB?

Answer 9

• MDT approach
• RIPE antibiotics - 9-12months - longer for resistant cases
• monitor - to see if good or no response
• 3 wks if paralysis
• 6 wks if no paralysis
• +/- orthosis
• +/- surgery

Question 10

what drugs would you use for TB?

Answer 10

• rifampicin
• izoniazid
• pyrazinamide
• ethambutol

Question 11

when would you operate in TB?

Answer 11

• Progressive neurology
• intractable pain
• severe deformity (kyphosis) >60 deg
• progressive kyphosis in children
• failure to respond to medical management
• caseating lesion with poor Abx penetration

Question 12

what are the advantages of operating?

Answer 12

• decreased kyphosis
• earlier healing
• decreased sinus formation
• neurological recovery - potts abscess

Question 13

what are the surgical options?

Answer 13

-Anterior decompression - abscess
- strut grafting
- posterior instrumentation - active disease and kyphosis

Question 14

what are the risks of TB spine?

Answer 14

• instability
• neurology
• paraplegia
• chest involvement