A 42-year-old man was admitted with complaints of low back pain and intermittent right thigh pain. Three months previously, he fell from the stairs and reported immediate pain with intermittent right thigh pain. Initial L-spine magnetic resonance imaging (MRI) showed left central disc herniation at the L4-5 level (Fig. 1), and the patient received IDET at a local hospital. The patient continued to report low back pain that was managed with narcotic analgesics after the IDET procedure. Seven weeks after the IDET procedure, the patient reported aggravated low back pain. Blood test results, including the erythrocyte sedimentation rate and C-reactive protein levels, were slightly elevated. Follow-up MRI was performed, and his referring physician thought the likely diagnosis was spondylodiscitis at L4-5 with a small epidural abscess. Antibiotic treatment with ciprofloxacin was administered for 3 weeks, but the patient reported no improvement. Finally, he was transferred to our institute 3 months after the intradiscal procedure.
At admission, the patient still reported moderate low back pain with intermittent right thigh pain. The patient had no history of hypertension, diabetes, hepatitis, tuberculosis, or allergy. There were no constitutional signs or symptoms such as fever or chills. Physical examination findings were unremarkable except for low back pain. Neurologic examination results were normal. Laboratory findings, including erythrocyte sedimentation rate and C-reactive protein levels, were slightly elevated.
Radiographic findings were non-specific. Computed tomography (CT) showed a smooth, round-shaped, multilobulated bony defect at the L4-5 spinal segment with a sclerotic margin (Fig. 2A). Follow-up MRI showed an approximate signal change of the lesion at the L4-5 intervertebral disc and L4-5 vertebral bodies. The lesion had markedly increased in size and had an increased T2 signal. In addition, contour bulging of the epidural space was present at the L4-5 intervertebral disc (Fig. 2B). The T1-weighted MRI showed diffuse marrow edema at the L4-5 intervertebral disc (Fig. 2C). To rule out an infectious etiology, bone biopsies were obtained from the L4 and L5 vertebral bodies and the L4-5 intervertebral disc. The material underwent aerobic, anaerobic, fungal, mycobacterial cultures and histologic examination. Histologically, necrosis of the bone with focal fibrosis was seen with empty osteocyte lacunae. There was no evidence of infection, including granuloma, based on biopsy results. Result of all cultures were also negative. No antibiotic treatment was administered on discharge.
During follow up, sedimentation rate, C-reactive protein level, and complete blood count were unchanged and within normal limits. At the 1-year follow-up, although the patient continued to report radiating leg pain, the low back pain had much improved. Repeat CT and MRI 12 months after IDET showed a bony defect at L4-5 and a decrease in size of the L4-5 intervertebral disc lesion (Fig. 3).