Postoperative discitis: outcome and late magnetic resonance image evaluation of ten patients.

Background and aims: MRI has proven to be the most effective method for demonstrating suspected postoperative discitis. The prognosis of discitis varies markedly in different series. The purpose of this study was to analyze the clinical outcome and late MRI findings of the patients with postoperative discitis.

Material and methods: The medical records of ten patients with discitis and of ten patients without infectious findings following lumbar discectomy in 1993 to 1995 were reviewed. A clinical follow-up investigation with a detailed questionnaire and MRI was performed. Without knowledge of the clinical history, a radiologist selected the cases of discitis based on evaluation of the MRI pictures, and thereafter after a combined analysis of preoperative CT scans and of the MRI pictures.

Results: The follow-up MRI demonstrated characteristic findings in every discitis case. However, similar changes were seen in four cases of the control group. The discitis group had more symptoms, a longer sick leave and less return to previous occupation than the control group.

Conclusion: As a late examination, MRI is insufficient in itself for diagnosis of earlier discitis. Postoperative discitis lengthens the sick leave markedly. Patients with postoperative discitis are rarely capable to return to a physically strenuous work. Every effort, including antibiotic prophylaxis, should be undertaken to reduce the risk of this serious complication.