TUBERCULOSIS OF THE SPINE AND MANAGEMENT

Tuberculosis of spine and sequel

1. TUBERCULOSIS OF THE SPINE Dr Gokul Junior Resident Orthopaedics

2. INVESTIGATIONS

3. Lab Reactive lymphocytosis ESR - raised SMEAR – positive in 10 - 30% CULTURE – BACTEC – growth detected in 5-10 days MGIT – 7-12 days GeneXpert (CBNAAT) – rapid detection (<2h)

4. BIOPSY CT/Fluoroscopic guided FNAC – diagnostic in 88 to 96 % cases. Biopsy specimen should always be sent for Staining Culture PCR HPR

5. IMAGING Difficult to diagnose radiologically in the early stages Sites Paradiscal Central Anterior Appendiceal 7% -- skip lesions

6. 1. PARADISCAL Earliest – disc space narrowing May be associated with loss of definition of para discal margins Trabecular destruction may take 3-5 months to be identifiable Peri articular osteoporosis

7. Paravertebral shadows Granulation tissue Abscess Cervical – anterior soft tissue widening Above cricoid – 0.5cm Below cricoid – 1.5cm Upper Thoracic (AP view) V – shaped shadow stripping the lung apices infero -laterally Squaring of superior mediastinal borders

8. Upper thoracic (C7 – D4) (Lateral view) Tracheal shadow displaced >8mm Below D4 Fusiform abscess (bird nest appearance) Large abscess – mediastinal widening Abscess under tension – may be globular Abscess above the vertebral attachment of diaphragm – stay in the thorax Below diaphragm – extend along the psoas muscle

9. Long standing abscesses in thoracic spine – scalloping of anterior vertebral borders while the discs are spared.  SAW TOOTH appearance Vertebral bodies are typically wedged Knuckle - 1 or 2 Angular kyphosis - >3 Round kyphosis Severe kyphosis in lumbar spine is rare Pre existing lordosis Large size of vertebrae

10. BIRD’S NEST ABSCESS

11. CENTRAL Starts from the centre of the vertebral body Batson’s venous plexus/branches of posterior vertebral artery Vertebral body shows: Loss of normal trabeculae Areas of destruction Ballooning Concentric collapse in later stages

12. Minimal loss of disc space Paravertebral shadow is not well marked

13. ANTERIOR Infection starts beneath ALL and periosteum More common in the thoracic spine in children Collapse of vertebrae and disc space narrowing – occurs late Shallow erosions seen on anterior surface of vertebral bodies. Stripping of periosteum – loss of blood supply – more liable to destructive changes

14. APPENDICEAL Isolated TB of the pedicle and laminae, transverse process or spinous process Seen as erosive lesions, paravertebral shadows with intact disc spaces

15. Limitations of xray Lesion is seen only when 30-40% calcium content is lost Involvement of neural arch not well seen Lesions <1.5cm may not be apparent Degree of neural compression cannot be judged Abscesses cannot be correctly assessed

16. MYELOGRAPHY Made obsolete by MRI Used now to know the adequacy of surgical decompression if patient not showing neural recovery.

17. CT Better visualisation of isolated neural arch lesion Early stages – erosion or osseous destruction Late stages – sequestrum and heterotopic bone formation Axial view – useful in assessing the progression of disease during treatment

18. Bone destruction patterns seen on CT OSTEOLYTIC Anterior or central part of vertebrae affected Spontaneous decompression and drainage of a vertebral body abscess --> paraspinal abscess Diagnosis is assisted by TB elsewhere Painless lesion Large soft tissue swelling with calcified contents

19. FRAGMENTARY Most common Numerous small residual bony particles seen in destroyed areas If this type of destruction is associated with paravertebral soft tissue mass – strongly suggestive of TB SUBPERIOSTEAL Anterior margins of the vertebral body has a ragged appearance Hypodense abscess with ring calcification in psoas muscles

20. LOCALISED AND SCLEROTIC Localised destruction with sclerotic margins Represents slow destruction or long standing infection with a good immune response More often seen after some length of chemotherapy

21. MRI Soft tissue topography is better shown by MRI Delineates the following: Extent of disease and spread of debris under the ALL and PLL Subligamentous spread of a paraspinal mass Pattern of abscess spread. TB – smooth margin – subligamentous Pyogenic – irregular margins – erodes ligaments

22. Cold abscess – post gadolinium MRI shows rim enhancement around abscess pyogenic abscess – diffuse enhancement Improved detection of epidural extension of abscess Can delineate isolated extradural lesion from intramedullary lesions Useful in followup of disease.

23. TB vs Pyogenic Preservation of IV disc in TB Cortical definition of affected vertebrae being lost in TB Pyogenic spondylitis is confined to vertebral marrow with no significant extension into intraspinal region

24. CHANGES IN CORD Cord edema . Myelomalacia – irregularity of cord associated with patchy hyperintensity on MRI Cord atrophy – apparent loss of cord size Syringomyelia Thickening of dura – arachnoid complex Arachnoiditis

25. Types of extradural compression FLUID - diffuse signal, hyperintense on T1, hypointense on T2 CASEOUS TISSUE – mildly hyperintense on T1 and T2 GRANULATION TISSUE – heterogenous signal

26. TREATMENT

27. Universal surgical extirpation – surgery + chemotherapy for all cases MIDDLE PATH REGIMEN – long course of chemotherapy + sugery only for complications MODIFIED MIDDLE PATH REGIMEN – 6 to 9 months chemotherapy + surgery only for complications

28. SURGERY Aims To establish diagnosis To treat spinal deformity, instability and neurological deficit. Large cold abscesses may need drainage.

29. Cases without neurological deficit Indications for surgery Uncertain diagnosis requiring open biopsy Mechanical instability – panvertebral disease Inadequate improvement on ATT Severe deformity – kyphosis > 60

30. Ancillary treatments Cervical spine – ambulant chemotherapy with a four post collar Dorsal and DL spine – ambulant chemotherapy with ASH brace Lumbar and LS spine – ambulant chemotherapy with taylor’s brace / ASH brace

31. Monitoring Increased HB and RBC count Decrease in ESR Xray – remineralisation, sharpening of disc margin, osseous or fibro-osseous fusion MRI – at 9, 12 and 18 months – resolving collection, reduction in marrow edema Staging of neural deficit

32. Predictors of refractory cases Worsening of local tenderness, fever Rising trend in ESR MRI showing deterioration of lesion at 5-6 months New lesions Failure of healing of ulcer/sinus New cold abscess/lymph node Wound dehiscence in a postoperative case

33. Cases with neurological deficit Indications for surgery Clinical : Rapid onset paraplegia Severe paraplegia – flaccid paraplegia, paraplegia in flexion Spinal tumor syndrome Paraplegia with neural arch affected Recurrent paraplegia Massive prevertebral abscess

34. Treatment factors: Neurological complications not improving Neurological complication getting worse New neurological complication developing Imaging: Bilateral pedicle destruction – instability Panvertebral involvement with scoliosis and/or severe kyphosis Extradural compression of cord by granulation/caseous tissue Paraplegia by compression of sequestra /disc Patient factors: Painful paraplegia – severe spasm or root compression Paraplegia with onset in old age because of risks of immobilisation

35. APPROACHES Upper cervical – transoral or retropharyngeal approach Cervical – anterior approach Dorsal – extrapleural anterolateral approach Lumbar – posterior approach is preferred

36. Instrumentation - indications Panvertebral disease Long segment disease Lumbar and cervical spine Correction of kyphosis Lesion in a junctional area

37. FOLLOW UP Look out for development of new neurological signs Assess the neurological status weekly Repeat spine xray – every 3 months Repeat MRI – 6, 9, 12, 18 months following initiation of treatment At the end of treatment – follow up every 6 months for at least 2 years

38. PROGNOSIS Age – prognosis worsens with age General condition of the patient Level and segment – Cervico -dorsal junction and upper dorsal spine show poor neural recovery Kyphosis >60 – poor neural recovery Duration of paraplegia – Shorter duration – better recovery

39. Progression of deficit – Rapid = poor prognosis Severity of deficit – More severe at presentation = worse prognosis Type of vertebral destruction Anterior > panvertebral Nature of compression Extradural compression of fluid has a better prognosis than that with granulation/caseation Cord changes Preserved cord = better prognosis

40. Kyphosis in TB Rajasekaran has described four simple radiological signs which reliably identify children who are at risk of severe deformity. These signs are Separation of the facet joints Retropulsion Lateral translation Toppling