Aseptic Spondylodiscitis after Lumbar Discectomy: Case Report and Literature Review

Abstract

Introduction Aseptic inflammatory changes in the vertebral bone marrow, end plates and intervertebral discs have been described as part of different entities such as Modic changes (MCs). MCs are classified in three types according to the formation of vascularized fibrous, fatty, or cicatricial bone tissue. Radiologically, each type is distinguished by particular magnetic resonance imaging (MRI) findings. MCs can be seen as part of normal spinal degeneration or secondary to spine surgical procedures such as lumbar discectomy. Even though their prevalence varies between studies, in clinical practice they generally are infrequent radiological findings. Patient and Methods: A case report of a 26-year-old man with 10 days of postoperative intense low back pain refractory to oral analgesia after L4–L5 lumbar discectomy is presented. A nonsystematic literature review about postoperative MCs was conducted. Results The patient evolved with difficult pain management needing to be hospitalized and studied with laboratory examinations and spinal images. Elevation of inflammatory parameters and lumbar spine MRI with T1-weighted image hypointensity, T2-weighted image hyperintensity, and increased signal with gadolinium at vertebral bone marrow and end plates adjacent to L4–L5 disc were the main findings. Septic spondylodiscitis was suspected as differential diagnosis, but conservative treatment was followed by clinical observation and evaluation of inflammatory parameters. The patient evolved with a progressive decrease of back pain and slight elevation of control inflammatory parameters but neither antibiotic treatment nor surgery was needed. At 9th day of hospitalization, the patient was discharged given positive clinical response with no pain at rest and slight pain with movement. Ambulatory follow-up with laboratory and imaging study exhibited normalization of inflammatory parameters and resolution of vertebral bone marrow and end plates changes accompanied by remission of patient's pain. Conclusion MCs are infrequent radiological findings. Type 1 MCs show similar MRI findings to those seen in the infectious process of the spine, which turns septic discitis/spondylodiscitis the main differential diagnosis to discard. When MCs are present, laboratory and imaging evaluation has to be performed to rule out an infectious etiology. Evaluation of inflammatory parameters, diffusion-enhanced MRI, and analysis of MRI contrast enhancement patterns are useful tools for this purpose. Because of the significant association between MCs and low back pain, symptomatic MCs must be treated with a first-line conservative treatment of analgesia and physical activity restriction.