Generally, the infection is spread to the vertebral body by a vascular route. The veins in the lower spine (Batson’s plexus) drain the pelvis and provide for a direct route of entry for the bacteria to get into the spine. For this reason, there is a preponderance of infections in the spine that occur after a urologic procedure (e.g. cystoscopy).

Vertebral osteomyelitis may also be referred to as spinal osteomyelitis, or a spinal infection.

Common Causes of Osteomyelitis

Patients susceptible to osteomyelitis include:

• Elderly patients
• Intravenous drug users
• Individuals whose immune systems are compromised

Conditions that compromise the immune system include:

• Long-term systemic administration of steroids to treat conditions such as rheumatoid arthritis
• Insulin Dependent Diabetes Mellitus
• Organ transplant patients
• Acquired Immune Deficiency Syndrome (AIDS)
• Malnutrition
• Cancer
• Intravenous drug abuse is a growing cause of spinal infections.

Typically, the organism most likely to infect the spine is Staphylococcus Aureus, but in the intravenous drug population, Pseudomonas infection is also a common cause of spinal infection. The treatment for these two pathogens requires different antibiotic therapy.

SYMPTOMS:

Symptoms of back pain due to a spinal infection often develop insidiously and over a long period of time.

In addition to back pain, which is present in over 90% of patients with vertebral osteomyelitis, general symptoms may include one or a combination of the following constitutional symptoms:

• Fever, chills, or shakes
• Unplanned weight loss
• Nighttime pain that is worse than daytime pain
• Swelling and possible warmth and redness around the infection site

A spinal infection rarely affects the nerves in the spine. However, the infection may move into the spinal canal and cause an epidural abscess, which can place pressure on the neural elements. If this happens in the cervical or thoracic spine, it can result in paraplegia or quadriplegia. If it happens in the lumbar spine it can result in cauda equina syndrome (a syndrome that leads to bowel and bladder incontinence, saddle anesthesia, and possible lower extremity weakness).

The most common site of vertebral bone infection is in the lower back, or lumbar spine, followed by the thoracic (upper) spine, the cervical spine (neck). It may also develop in the sacrum, the bone at the very bottom of the spine that connects to the pelvis.

Symptoms of vertebral osteomyelitis are highly variable depending on the patient, the location of the infection, and how far advanced it is. For example, while a fever is a typical symptom, some people may have no fever and others may run a high fever.

TREATMENTS:

Treatment for vertebral osteomyelitis is usually conservative (meaning nonsurgical) and based primarily on use of intravenous antibiotic treatment. Occasionally, surgery may be necessary to alleviate pressure on the spinal nerves, clean out infected material, and/or stabilize the spine.

Nonsurgical Treatments for Vertebral Osteomyelitis

Treatment for a spinal infection usually includes a combination of intravenous antibiotic therapy, bracing, and rest

Most cases of vertebral osteomyelitis are caused by Staphyloccocus Aureus, which is generally very sensitive to antibiotics. The intravenous antibiotic treatment usually takes about four weeks, and then is usually followed by about two weeks of oral antibiotics. For infection caused by tuberculosis, patients are often required to take three drugs for up to one year.

Bracing is recommended to provide stability for the spine while the infection is healing. It is usually continued for 6 to 12 weeks, until either a bony fusion is seen on X-ray, or until the patient’s pain subsides. A rigid brace works best and need only be worn when the patient is active.

Surgical Treatments and Considerations

Surgical decompression is necessary if an epidural abscess places pressure on the neural elements. Because surgical decompression often destabilizes the spine further, instrumentation and fusion are also frequently included to prevent worsening deformity and pain.

1.  Lumbar Decompression

2. Anterior/Posterior Lumbar Fusion Surgery

If the infection does not respond to antibiotic therapy, surgical debridement and removal of infected material may be necessary. Most infections are predominantly in the anterior structures (such as the vertebral body) and the debridement is best done through an anterior (front) approach. Stabilization and fusion are also done after removing the infected bone.