Spinal InfectionsHimanshu Sharma

Spinal InfectionsObjectives

• Epidemiology

• Pathology

• Clinical features

• Management

• Prognosis

Spinal InfectionsEpidemiology

• 2 - 4% all cases of “osteomyelitis”

• Rare: 1 in 250,000/yr but rising incidence

• Post-op discitis = 2-3%

• Pre-antibiotic mortality = 25-70%

• Delayed diagnosis common (50%+ > 3/12)

Spinal InfectionsLevels

Spondylodiscitis / facet disease

• Lumbar (59%)

• Thoracic (33%)

• Cervical (8%)

Epidural abscess (in 7%)

• Cervical (6-18%) anterior

• Thoracic

• Lumbar

Spinal InfectionsRisk Factors

• Peak incidence 7th decade

• Concurrent illness/infection

Diabetes Obesity

Immunosuppressed Malnutrition

Steroid therapy Irradiation

UTI

• Invasive procedures/ trauma

• Smoking

Spinal InfectionsPathology (1)

• Organisms

S aureus 30 -50% cases

Gram-negatives – UTI, Chest, Skin ulcers

Opportunistic in immune paresis

IVDA

• Route of spread

Haematogenous

Direct extension

Post-operative

Spinal InfectionsPathology (2)

• Vertebral metaphyses (end plate region)

= end-arteriole blood supply (filter)

Septic emboli

• Direct spread from implantation

Secondary spread to discs, paraspinal

tissues and spaces

Spinal InfectionsClinical Features

• Pain and focal tenderness 90%

• Fever 61%

• Root symptoms/signs 60%

• Abnormal neurology 20%

Also: deformity, muscle spasms, meningism, sinus,

and unexplained septicaemia

Investigations

• FBC• ESR• CRP• Blood & Urine cultures• Nutritional status • Biopsy

Spinal InfectionsDiagnosis

• Lab tests

White cell count 40-50%

ESR / CRP 80-90%

Positive Blood Culture 20-25%

• Imaging

• Biopsy

Spinal InfectionsPlain radiological findings

•Vertebral metaphyseal blurring

(osteolysis)

•Loss of disc height

•Endplate blurring

•Subchondral reactive bone

formation

•Bone destruction (and deformity)

•Soft-tissue shadows e.g.psoas

abscess

Pyogenicdiscitis/osteomyelitis

Bad disc = Good news

Spinal InfectionsImaging Studies - Isotopes

• Detect earlier than plain films

• High sensitivity / specificity

e.g. gallium + Tc = 95% accurate

• Little structural information

• False negatives in neutropenics

(gallium)

• False negatives in bone infarction (Tc)

Pyogenic spinal infectionsimaging studies - CT

• delineate bony margins / involvement

• soft-tissue invasion

• poor for outlining neural elements

• risk of spread if combine with myelography,

but can obtain CSF

• 3D/MPR useful for pre-op planning of

reconstruction

Spinal InfectionsDifferential Diagnosis

• Granulomatous disease

• Metastases/Myeloma

• Degenerative disease

• Osteoporosis

• Local Scheuermann’s

• Spondyloarthropathies

T1= signalT2= signal Ring enhancement

> 95% accuracy

Spinal InfectionsBiopsy

Biopsy (for identification of the causative organism)

• Closed needle biopsy (guided)

– 68 - 86% accuracy (false negative 30%)

• Open biopsy

– > 80% accurate (false negative 14%)

• Special lab techniques (DNA PCR, etc)

Biopsy principles

• Biopsy material should be sent to microbiology for gram stain & acid-fast stain, aerobic, anaerobic, fungal and mycobacterial cultures and for histopathological examination.

Spinal InfectionsTreatment Goals

• Establish diagnosis

• Clear infection and prevent recurrence

• Pain relief

• Protect / restore neurological function

• Maintain / restore spine stability

Changed Battlefield

• Territory

– Patients

• Weapons

– Antibiotics

–Surgery

• Enemy

– Microbiology

Territory - changed

• Patient• Population Greying• Type 2 DM• Cancer• Steroids• HIV• Drug Abuse

• Iatrogenic Immunosuppression

Transplants

Dialysis

Enemy - changed

• More Resistant Strains of Bacteria• Hospital Acquired Infection• More previously unsuspected causes

Weapons -

• Antimicrobials

• Type and Scope of Surgery

Why is it important?

• Consequence of Inappropriate Management

• Multiple Surgery• Pain • Paralysis• Death• Financial Cost

• Causes of Inappropriate Management

• Lack of awareness• Empirical Antibiotics• Inappropriate /Inadequate

Surgery

Spinal InfectionsTreatment (1)

Antibiotics

– sensitivities

– adequate dose (iv then oral)

– ensure MBC reached

– adequate duration (> 6 weeks)

– monitor response (clinical/ indices/ imaging)

– toxicity profile and monitoring

Spinal InfectionsTreatment (2)

Immobilisation

– bed rest

– moulded orthoses (low thoracic / lumbar)

– halo-vest or orthosis (cervical / high thoracic)

9/12

Pyogenic spinal infections