Review Question - QID 219102

The clinical presentation and imaging studies are consistent with a postoperative surgical infection. Surgical irrigation and debridement is the most appropriate treatment.

Postoperative infections are one of the most common complications of lumbar spine surgery. Reports show a 0.7% infection rate with lumbar diskectomy with prophylactic antibiotics. It has been documented that the use of a microscope doubles this infection rate to 1.4%. The risk of infection is even higher with spinal fusion because of the presence of spinal instrumentation, with some studies showing an infection rate of up to 10%.

Sasso et al. review the diagnosis and management of postoperative spinal wound infections. They report the S aureus is the most common organism causing postoperative spinal infections and account for > 50% of cases. Other organisms found in these infections include S epidermidis, Peptococcus, Enterobacter cloacae, and Bacteroides. They report preoperative antibiotic prophylaxis decreases the infection rate for all scenarios.

Cousins et al. review MRI imaging of the spine. They report a gadolinium-containing contrast enhancement is used to distinguish scar tissue, which enhances on MRI scans, from fragments of disk tissue in the epidural space that, lacking capillaries, do not enhance. In the patient with spinal infection, contrast medium administration shows enhancement in affected vertebral bodies and abscesses.

Figure A show a sagittal T1-weighted MR. Figure B shows a sagittal T1-weighted MR image obtained of the lumbar spine after intravenous administration of gadolinium. These studies demonstrate abnormal edema (white arrows in A and B) and enhancement in the L4 and L5 vertebral bodies (open white arrows in B) and intervertebral disc (white arrowhead in B), with partial destruction of the endplate (black arrows).

Incorrect Answers:
Answer 1: The clinical presentation is consistent with an infection which should be treated.
Answer 2: Placement of an lumbar drain is indicated with a persistent CSF leak that has failed multiple repair attempts.
Answer 3: IV antibiotics alone is not the appropriate treatment of a lumbar surgical infection.
Answer 4: A CT guided aspiration is not indicated.