Disc space infection

Discitis

Etiology

Iatrogenic: following surgery or disc cannulation

Can be primary in childhood

Spontaneously occuring spinal infections in adults involving the discs are due to osteomyelitis of the vertebral body – probably beginning in the end plate, not discitis

Childhood Discitis       

Menelaus M.B. Discitis JBJS 46B: 16-23, 1964

Wenger etal The spectrum of intervertebral disc space infection in children JBJS 60A:100-108, 1978

Incidence

Rare

Clinically   

Back pain

Difficulty walking or sitting


May be assoc with fever, malaise


May be preceded by URTI etc


Reduced motion, muscle spasm, abnormal posture

Investigation

Blood

ESR up

WCC usually normal


Blood cultures – +ve in 50%

> 6 wks post onset of symptoms organisms do not appear to isolated from blood cultures

Radiology

early normal


later – disc narrowing

progressive end plate lesions

erosion into the vertebral body


latest – fusion rare,  very little residual disc narrowing

Treatment

Rest – until no pain or limitation of motion, and until ESR normal

Antibiotics- indicated if febrile, +ve blood cultures, +ve biopsy, IV until pt comfortable, then oral for 3 more wks

Prognosis

Good- spontaneous recovery is almost the rule

Adult Discitis

Incidence

Discectomy, after open discectomy: 0-2.8%

Discography, 2 % without and 0.7 % with stilleted needles (0 % if Ab’s mixed in)

Chemonucleolysis,  up to 2 %

Percutaneous nucleotomy

Lumbar puncture

Aetiology

Bacterial contamination

Pathology

Bacteria introduced into disc

Progressive thinning of end plate with immature granulation tissue forming on the vertebral side of the end plate at 1 wk

By 3 wks the end plates are breached and nuclear material herniates into the vertebral body  – bacteria are destroyed in a florid vascular response

By 6 wks new bone is forming , disc material is replaced by granulation tissue

Clinically

Pain – severe, disabling, present at rest


Muscle spasm

Posture abnormal

Investigation –    

Blood

ESR up

WCC usually normal


Cultures usually negative

Radiology

Plain films initially normal

Disc narrowing at  2-3 wks

End plate erosions at 6 wks

Bone scan


CT


MRI

Treatment

Prophylaxis – sterile technique

Antibiotics are unable to arrest the progression of discitis once the

condition is established

Once the end plate is penetrated, antibiotics may have a role in prevention of vertebral osteomyelitis

Rest – support- may need to be for 6-8 mths

Anterior clearance and fusion if symptoms demand

Prognosis

IV or intradiscal antibiotics during discography have not been conclusively shown to decrease the rate of discitis over sterile technique alone.

Both single- and double-needle techniques when used with stylettes are superior to nonstyletted techniques.

Is a slowly resolving process in the majority discitis following open discectomy follows a more refractory course with most pts having disabling symptoms after 5 yrs