Medical Therapy
Antibiotics
Antibiotic treatment for diskitis (discitis) must be tailored to the isolated organism and any other sites of infection. Broad-spectrum antibiotics must be used if no organism is isolated; however, this is very rare, and other disease processes (eg, spinal tuberculosis) must be considered in the face of persistently negative cultures.
Parenteral antibiotics are a requirement, even for outpatients. They are usually administered for 6-8 weeks. Before parenteral therapy is discontinued, the erythrocyte sedimentation rate (ESR) should have dropped by one half to one third, the patient should have no pain on ambulation, and there should be no neurologic deficits (see Complications and Long-Term Monitoring). [1, 3]
The use of oral antibiotics after intravenous (IV) treatment has not been shown to be of added benefit.
Any laboratory or clinical sign of persistent infection should prompt another biopsy and continued antibiotic therapy.
Immobilization
Immobilization is necessary, especially in the initial stages of the disease. The goal of immobilization is to provide the opportunity for the affected vertebrae to fuse in an anatomically aligned position.
Two weeks of bed rest should be followed by external immobilization with a brace when the patient gets out of bed. Any pain on ambulation is an indication for continued bed rest. Generally, bracing is used for 3-6 months following initiation of treatment; however, even with the use of appropriate antibiotics and bracing, collapse of the vertebral segments and kyphos formation may occur.
Pain control
Pain medications can be a useful adjunct to antibiotic therapy, in that they allow increased mobilization. [2]
Surgical Therapy
Indications for surgery beyond open biopsy include the following:
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Neurologic deficit
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Spinal deformity
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Disease progression
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Noncompliance
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Antibiotic toxicity
The goal of surgery are as follows:
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To remove diseased tissue
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To decompress neural structures
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To ensure spinal stability
Although in most cases the vertebrae fuse spontaneously after diskitis and osteomyelitis, operative fusion can be a useful adjunct by allowing earlier mobilization of the patient. Despite early concerns, use of a fusion plug and metallic instrumentation in an infected field has not been shown to impede successful treatment.
The use of percutaneous endoscopic surgery to treat infectious spondylodiskitis has been described as safe and effective. [11]
Complications
Neurologic deficits develop in 13-40% of patients, especially those with diabetes or other systemic illnesses. Transfer to an institution with neurosurgical or orthopedic spinal care is warranted for any patient demonstrating neurologic decline for decompression and possible stabilization.
Long-term antibiotic therapy may lead to ototoxicity or renal toxicity.
Diet and Activity
No particular diet has been shown to have a clinical benefit in patients with diskitis.
Many authors believe that 2 weeks of bed rest with initial treatment helps prevent the development of a kyphotic deformity. Use of an orthotic brace to help stabilize the spine while spontaneous fusion takes place is recommended for 3-6 months. Ambulation is recommended only if the patient has neither pain nor radiographic signs of instability.
Prevention
No specific deterrence is available for diskitis except treatment of the underlying disease (eg, diabetes, sepsis).
Sharma et al reported on the severe complication of diskitis following diskography. [12] They found that the available clinical evidence did not conclusively demonstrate that IV or intradiskal antibiotics during diskography decreased the rate of diskitis in comparison with sterile technique alone. Animal model research supports prophylactic antibiotic use when used before iatrogenic inoculation of intervertebral disks. Both single- and double-needle techniques when used with stylettes are superior to nonstyletted techniques, according to the authors.
Consultations
Consultations to be considered include the following:
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Infectious disease
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Neurosurgery
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Orthopedic spine surgery
Long-Term Monitoring
Once the correct treatment is implemented, monitor patients to rule out progressive neurologic deficit.
A falling ESR is consistent with successful treatment. Although ESR values should fall by at least one third to one half, rarely do they return to preinfection levels. Reduction of C-reactive protein (CRP) levels has been shown to be more sensitive than ESR in some studies.
Serial radiographic examination is a necessity to detect bony collapse or deformity. Successful treatment is accompanied by appropriate changes, including sclerosis of the endplates, on plain radiography and computed tomography (CT). Nevertheless, radiographic findings are significantly slower than clinical response and cannot be used to assess eradication of infection.
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Axial CT scan in a patient with diskitis demonstrates extensive destruction of the vertebral endplate. Note the preservation of the posterior elements, including facet joints, lamina, and spinous process. This is characteristic for pyogenic diskitis and less common in tuberculosis (Pott disease).
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Sagittal T1-weighted MRI of the lumbar spine in a 74-year-old man, revealing diskitis of the L4-L5 disk space. Note extensive destruction of the endplates of the adjacent vertebral bodies. No compression of the thecal sac is present, which is an important consideration when contemplating surgical intervention.
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Contrast-enhanced sagittal T1-weighted MRI image in a 55-year-old woman shows thoracic diskitis with an associated epidural abscess and spinal cord compression. Because of the significant cord compression, this patient underwent surgical decompression.
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Trajectory of a needle in a biopsy of the infected disk space guided by CT scan. Care is taken to avoid the thecal sac and nerve roots.
