Treatment of spinal infections

Multiple treatment options are available for spinal infections, but surgery cannot be avoided in certain cases (e.g., significant neurological changes).

What does a spinal infection mean?

Spinal infections mean that a pathogen gets into the spine and starts to proliferate by colonization. The infection may affect the spine muscles and the soft tissues (paravertebral abscess), it may also present around the nerve structures (epidural abscess) in the spinal canal, moreover, it may attack the intervertebral discs (discitis), the vertebral endplates, and the vertebral bodies (osteomyelitis).

The most common cause of the infection are purulent bacteria (out of these, the Staphylococcal strains, which are also part of the normal skin flora). The disease may be induced by other, more rare pathogens too, among others by Mycobacterium, which causes specific (granulomatous) inflammation, or fungal infections, and by parasites in certain cases.

The pathogens may reach the spine in multiple ways. One possible way is that the pathogen spreads to the spine from the blood stream from an (even latent – not yet symptomatic) infectious focus (from an e.g., gynecological, ear nose throat, urological, skin, or soft tissue vegetation, or from a vegetation that is present in the heart valve). However, an infection may also develop as a consequence of invasive (the patient’s skin, mucous membrane, or other body opening is penetrated by physical) interventions (injection, previous surgery, disturbed wound healing).

The body responds to the colonizing and proliferating pathogen by a reaction. This can have multiple symptoms. Its goal is to prevent the tissue damage from spreading further, remove and neutralize the pathogen, eliminate the damaged tissues, initiate recovery, and tissue healing. However, the spine structures, which were affected (attacked) by the pathogen, may get damaged in this protective reaction, and this may lead to the development of further symptoms.

Which are the potential symptoms of a spinal infection?

The symptomatic presentation of the disease depends both on the pathogen’s ability to cause damage (“virulence”), as well as on the patient’s immune status. Usually it is a “latent” disease, which develops slowly, and oftentimes it is accompanied by non specific symptoms (symptoms that are not only typical for spinal infections). Despite of this, symptoms may present rapidly in certain cases, and the disease may produce symptoms quickly with a rapid disease course:

• Pain at the area affected by the infection.
• Fever, chills, subfebrility.
• The presence of neurological symptoms: weakness, paralysis, numbness of the limbs, bowel, and urinary incontinence.
• In children: irritability, and refusing to move (crawling, sitting, or standing) depending on the age.

How is the disease diagnosed?

Clarifying the medical history, detecting the clinical symptoms, and performing a medical physical examination play a significant role in the diagnosis of spinal infections. Additionally, laboratory tests and imaging scans also play an important role in the diagnosis.

During laboratory tests, the elevation of the inflammatory laboratory parameters (C reactive protein and procalcitonin, white blood cell count, red blood cell sedimentation rate) may be detected with the development of anemia. It is also important to detect the pathogen (with a bacterial culture test) from the affected areas or from blood (by taking a blood culture test).

Out of radiological diagnostic scans, the MRI scan is the most sensitive to confirm the infectious processes, but if it is not feasible (if the patient has a non MRI conditional pacemaker; the scan cannot be performed due to significant pain; or an MRI scan is not available), a CT scan may help in making the diagnosis.

What are the treatment options?

Non surgical (conservative) treatment

Conservative treatment of the symptoms can be undertaken in all those cases, where there are no significant neurological changes (paralysis, incontinence), the risk for spinal instability, intolerable pain syndrome (unmanageable by drugs), and the risk for a threatening septic condition are not present.

Aims:

• Maintaining the stability of the spine and its neurological functions.
• Reducing pain.
• Treating infections.

Methods:

• Rest (“bed rest”), avoid loading.
• Reducing pain.
• External fixation of the spine, mobilization in a brace (a hard brace, which provides external stability for the spine).
• Antibiotic treatment.

Surgical treatment may become necessary in those cases where conservative treatments provide only temporary results, they are ineffective, or where the condition deteriorates.

Surgical treatment

Surgical treatment is recommended in every case when:

• Neurological abnormalities develop or there is a risk for that (paralysis, incontinence).
• The severity of the disease endangers the stability of the spine (e.g., due to infection induced vertebral destruction).
• The infected tissues cause the significant narrowing of the spinal canal.
• The physiological curvatures of the spine grossly change (severe segmental kyphosis develops).
• The risk for a septic condition is present.
• The conservative treatment is ineffective.

The surgical treatment has three main goals. First, the maintenance and the attainable improvement of nerve functions through early nerve release (and stabilization, if necessary). Then, preventing the further spread of the infection by aggressively removing the tissues (surgical debridement), which were affected by the infection and demised from it, or which show decreased viability. Finally, collecting specimen during surgery for bacterial culture (and for histopathological examination to confirm the diagnosis in some cases), which will allow the targeted antibiotic treatment of the pathogen.