Incidence
- tuberculosis is a disease of the third world
- which amounts to about 80% of the population of the world
- annual risk of infection 1,5 - 2,5% in the sub-Saharan Africa
- primarily pulmonary infection
- EPTB presents with increasing frequency
- incidence of urogenital tuberculosis is 28%
- miliary tuberculosis 27% and
- spinal tuberculosis 10% to 25%
- most common at thoracic -Th-L, than lumbar and rare at the cervical spine
- C-spine TB is 3,5% of all spinal TB
- new tendency - increasing HIV infection
- →co-infection w/ TB from endogenous reactivation of the dormant TB infection
- predisposing factors
- socio-economic factors - nutrition, housing etc.
- DM
- alcoholism
Aetiology
- caused by Mycobacterium tuberculosis
- two types of tuberculosis are found in the spine
- human type → originates from a primary focus in the lung & then spreads
haematogeneously to the vertebrae - bovine type → ingested w/ milk into the intestinal canal & absorbed into the mesenteric
glands & from there it spreads haematogeneously to the spinal column
- human type → originates from a primary focus in the lung & then spreads
- ? lymphatic spread as well
Pathology
- in the vertebral column the TB organism destroys the bone at the sub-chondral level
- eventually the vertebrae collapse & form a gibbus
- why in vertebral body ?
- rich venous plexus (Batson)
- sluggish circulation
- daily trauma
- tubercle forms & spreads along planes
- Th-L spine - psoas abscess, ant. & post. longit. Lig
- C-spine - axilla, along brachial plexus
Neurology
- gradual onset & progression, mostly if > 10 yrs old
- Frankel grading
- seen in 40 % of patients & is d/t
- inflammatory myelitis
- P° from an abscess or from deformity
- vascular causes -acute onset
Clinical
- Symptoms
- often present late - pain not a major symptom
- deformity (gibbus ) - commonest presenting feature
- most serious symptoms are paresis or paralysis
- less common presentation includes abscesses or sinuses
- other symptoms as coughing, fever, night sweat, weight loss etc. must be looked for
- Full work up
- all patients should be admitted - ideally
- history - TB contact, previous treatment
- examination
- general
- chest, lymph nodes, wasting
- look for abscesses - axilla, hip
- spine - most common deformity is a kyphosis
- documentation of neurological status
- general
- FBC + ESR
- Iymphocytosis & elevated ESR (may be > 100mm )
- HIV test recommended
- skin testing (PPD)
- supportive for the dg. of TB
- excludes other chronic bone infection w/ similar X-ray e.g. Salmonella typhi & fungi
- febrile antigens (CRP)
- 3X urine & sputum
- for microscopy (AFB) & culture
- 55 - 75% accurate
- X rays - spine + chest
- exclude other pathology in adults
- ? myeloma (bence-jones proteins, protein electrophoresis)
- tumour markers
- Widal test (salmonella typhi) & serology for brucella
- tomo's shows posterior elements well, may demonstrate cavitation
- bone scan - identifies skip & other bony lesions
- tissue biopsy - MC&S, TB, Fungi, Bactec, also for histology
- 75% accuracy
X ray investigations
- Plain X rays
- AP, lateral spine & CXR
- entire spine to exclude multifocal dx.
- w/ active infection 2 vertebrae usually involved - occasionally 1 only
- classic appearance
- 2 vertebrae involved, loss of the adjacent end plate cortical definition (lytic lesion)
- anterior (vertebral body) involvement mostly, posterior < 10%
- osteoporosis
- paraspinal abscess on the AP (especially well seen on CxR)
- healing phase
- calcification, sclerosis
- angle of the gibbus measured from
- upper end plate of the 1st uninvolved prox. vert. to lower end plate of the 1st uninvolved distal vertebra
- prediction of the final angle of the gibbus after conservative Rx is important
- may determine whether chemotherapy or surgery is Rx of choice
- Tomography
- to determine posterior element involvement
- Bone scan
- defines the extent of the disease, skip vertebral lesions & other bony involvement
- 35% false negative
- Myelography
- useful as pre-op investigation if MRI is not available
- may cause neurological deterioration
- for small children - GA
- CT scan
- can assess posterior element damage + extent of body involvement & number of bodies involved
- paraspinous soft tissue involvement, psoas abscess, epidural abscess
- MRI
- best definition of the extent of the anterior pathology, possible cord injury & soft tissue involvement
Differential dg
- Brucellosis
- 2% of all brucellosis involves spine
- risk factors - working w/ animals
- vets
- farmers
- southern Free State
- dg.: brucella AB levels
- Rx: Streptran & Rifampicin for 3/12
- Salmonella
- uncommon < 1% - sickle cell predispose
- tends to be multifocal - check proximal humerus, distal femur
- X-ray - same as TB
- Dg.: Widal titer - not always
- Rx.: AB
- Aspergillus
- fungal infection
- if << immune function
- HIV
- malignancy
- transplant pts.
- Rx: anti-fungal, most need surgery
- fungal infection
- Tumours
- always consider
Treatment principles
- controversial especially w/ regard to the role of surgery
Children
- treatment is started on clinical & X ray findings
- in general, children are treated non-operatively
Adults
- bacteriological & histological confirmation of disease before Rx. (unless surgery is planned)
→ needle biopsy below T9, above T9 open biopsy - most adults with neurology need surgery + chemotherapy
Choice of treatment
- ambulatory chemotherapy or
- strict bed rest + chemotherapy or
- surgery + chemotherapy
Conservative treatment
- hospitalise
- protect cord, column & skin - treat spine as unstable
- restrict activity - bedrest
- chemotherapy - 3 drugs for children:
- rifampicin : 6 mg/kg max. 300 mg
- isoniazide (INH): 15 mg/kg max. 600 mg
- pyrazinamide (PZA): 20 mg/kg max. 2-3g
- 4 for adults: + ethambuthol 15-25 mg/kg max. 1,2 g
- in a single dose daily w/ Pyridoxine 25 mg (for peripheral neuritis)
- continued for 9-12/12 or until ESR normal & X rays show no sign of active infection
- 2nd line of drugs - for resistant AFB - PAS, ethionamide
- nutrition
- physiotherapy
- disability grant - 1 year for non-paraplegics, permanent for those with neurologic deficit
- brace, POP jacket
- monitor - clinical, ESR, LFT, X ray monthly
- discharge & follow-up
Surgical treatment
- Definite indications
- anterior + posterior vertebral involvement → translational instability
- anterior decompression & graft + posterior stabilisation
- anterior + posterior vertebral involvement → translational instability
- significant neurology (Frankel A - C) or neurological deterioration while on conservative Rx
- multiple level involvment & progressive kyphotic deformity
- doubtful dg. - must have tissue dg.
- surgical experience & facilities basic requirements
- Relative indications
- severe predicted kyphosis ( > 60° )
- factors that influence an increase in gibbus angle
- site: thoracic > T-L lesions > lumbar spine
- pre-treatment angle: the greater the initial angle, the less the chance to increase
- No. of levels involved
- prediction of kyphotic angle in degrees
- factors that influence an increase in gibbus angle
- severe predicted kyphosis ( > 60° )
- Y = A + Bx (A= 5.5°, B= 30.5°, x = the amount of the initial loss of the vertebral body)
- recent onset of paraparesis w/ minimal bone destruction
- prediction of kyphotic angle in degrees
- Definite indications
* loss of every whole vertebral body = 30 to 35° of gibbus
* children - gibbus angle tends to decrease as they grow
- recent onset of paraparesis w/ minimal bone destruction
- strict bed rest + chemotherapy until full neurological recovery
- if no neurological improvement after 4 to 6 weeks ---> surgery
Surgery
- acute onset paraplegia - vascular
- paraplegia > 6-9/12
- total motor loss
- incontince
- vibration sense loss
- Anterior approach
- generally indicated because
- most have vertebral body disease
- compression of the cord is anterior
- generally indicated because
- Procedure - anterior decompression, radical debridement + strut graft
- all pathological bone & disc excised leaving healthy bleeding bone
- fibula or rib strut
- most common late complications are d/t anterior graft failure (slip, absorption & #)
- Posterior arthrodesis
- recommended
- more than 2 vertebral bodies involved
- ant + post vertebral involvement - translational instability
- anterior strut graft failure - instability
- in children always if anterior fusion done → to prevent progressive kyphotic deformity w/ growth
- instrumentation commonly used
- Harrington or Luque rods, or pedicle screw - hook systems
- sublaminar Mersiline tape if < 5 years, sublaminar wires for older children & adults
- recommended
- Post-operative bracing
- for 3 - 6 months
- TLSO
- POP jacket
- for 3 - 6 months