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Spinal infection Pramot Tanutit, M.D.

Department of Radiology, Songklanagarind Hospital

Faculty of Medicine, Prince of Songkla University

Outline

• Anatomy

• Pathogen

–Pyogenic spondylodiscitis

– Tuberculous spondylitis

• Mimicking disease

ANATOMY Pyogenic spondylodiscitis

• Route of spreading– Hematogenous spread

– Contiguous source

– Direct impaction

– Postoperative infection

• Pathogen: S. aureus(55-90%), Streptococcus, Pneumococcus, Enterococcus, Escherichia coli, Salmonella, Pseudomonas, Klebseilla

Resnick, Bone and joint imaging, 2005Radiographics 2009; 29:599-612

• Location: Lumbar(48%)>Thoracic(35%)>Cervical(6.5%)

– Usually one segment

• Onset: acute to subacute period

• Clinical: back pain, fever, focal neurological manifestation(late)

Ross, Diagnostic imaging spine, 2015

Pyogenic spondylodiscitis

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Stage of infection Characteristic

• Location: Lumbar

• Disc and end plate: Destroyed

• Marrrow: Extensive edema

• Paraspinal involvement: Small abscess with thick, irregular rim enhancement

• Epidural involvement: Positive

Ross, Diagnostic imaging spine, 2015Radiol Clin N Am 50(2012) 777-789

• Location: Lumbar

• Disc and end plate: Destroyed

• Epidural involvement

• Paraspinal involvement:Small abscess with thick, irregular rim enhancement

• Marrow: extensive edema

T2W T1W-Gd

Tuberculous spondylitis

• Onset: subacute to chronic

• Route of spreading: mainly hematogenous route

• Clinical: lack of symptom in early phase

Ross, Diagnostic imaging spine, 2015Resnick, Bone and joint imaging, 2005

• Location: Mid-thoracic or thoracolumbar> lumbar, cervical

• Possible isolated posterior element involvement

• Lamina> pedicle> spinous process> transverse process

Ross, Diagnostic imaging spine, 2015

Tuberculous spondylitis

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Characteristic• Disc and end plate: Early spared

Tuberculous spondylitis

Characteristic

• Location: Midthoracic/ thoracolumbar

• Marrow: Ill-defined marrow alteration

• Paraspinal involvement: Large abscess, thin smooth rim enhancement

• Epidural involvement: Positive

• Other: Gibbus(advanced), subligamentous spreading, multiple involvement, skip lesion

Ross, Diagnostic imaging spine, 2015Radiol Clin N Am 50(2012) 777-789

Imaging

Subligamentous spreadingLarge right psoas abscess Characteristic

• Paraspinal involvement: Large abscess(+/- calcify), thin smooth rim enhancement

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Calcified nodes

Pyogenic Tuberculous

Location Lumbar Mid-thoracic/ thoracolumbar

Disc & endplate Destroyed Early spared

Bony part Body involvement Anterior body, isolated posterior element

Paraspinalinvolvement

Small abscess with thick, irregular rim enhancement

large abscess(+/- calcify), thinsmooth rim enhancement

Epidural + +

Other Leukocytosis Gibbus(advanced),subligamentous spreading, multiple involvement

Ross, Diagnostic imaging spine, 2015Radiol Clin N Am 50(2012) 777-789

Our study, 2011

• The Combination of Magnetic Resonance Findings in Differentiation between Pyogenic Spondylitis and Tuberculousspondylitis

• Population: 150 patients(2003-2010)

Table: MRI findings of TB and pyogenic spondylitis

Parameters TB Pyogenic Sig.C-spine level /

Thoracic spine level /

Lumbar spine level / /

Sacrum level / /

Skip lesion /

Subligamentous spreading >2 levels / /

Intraosseous abscess / /

Para/perispinal abnormal signal / /

Para/perispinal abscess formation / /

Probability of pyogenic spondylitis

Intraosseousabscess

para/ perispinalabnormal

signal

Subligamentouosspreading > 2

levels

Sacral spine involvement

Probability(%)

+ 66

+ 70

+ + + 72

+ + 92

Enhancing lung nodule with central necrosis at left apical lung

Left paravertebral abscess

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Rim-enhancing mediastinal node (Tbc lymphadenitis)

Prevertebral abscess Penumbra sign***

Mycotic aortic aneurysm, TB

Warning*** TB spondylitis with collapse

mimic TUMOR

Differential diagnosis

• Spondyloarthropathies

• Degenerative endplate change(Modic I)

Spondyloarthropathies

Romanus lesion

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Spondyloarthropathies

Romanus lesionAndersson lesion

Degenerative disc disease

Girl 4 YO, neck pain and low grade fever for 3 days Take home point

• Infected spondylitis

• Pyogenic: lumbar, extensive marrow edema, small abscess

• TB: T or TL spine, involve posterior element, intraosseousabscess, subligamentous spreading(>3 levels), large abscess, calcification, calcified nodes

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Take home point

• Contrast enhancement: bioactivity, extension of disease

• Plain film or CT scan: calcification, ossification

• Difficult case: 2 wks follow up

• IVR: vertebral biopsy or aspiration

Thank you