A 68-year-old female patient with lumbosacral pain caused by a fall was admitted to a local 3rd tier hospital without fever, fatigue, and sweating. Blood tests showed that white blood cell (WBC) count was 7.42x109/L and neutrophils accounted for 64.3%, erythrocyte sedimentation rate (ESR) was 10mm/hr, and C-reactive protein (CRP) was 3mg/L. X-ray showed a wedge-shaped change of the L4 vertebra (Figure 1A and B). Magnetic resonance imaging (MRI) demonstrated hypointense signal of L4 vertebra with a clear horizontal fracture line on T1-weighted imaging (T1WI), mixed intensity signal of L4 vertebra on T2-weighted imaging (T2WI), hyperintense signal, and a clear horizontal fracture line of L4 vertebra on Fat-suppressed T2-weighted images (FS-T2WI), quasi-circular areas of high-intensity signal around L5 was due to MRI artifact (Figure 1C-E). Diagnosis of fresh OVCF of L4 was explicitly based on trauma history and assistant examinations. The patient received vertebroplasty immediately due to unbearable pain. Her lumbosacral pain was relieved, and the spinal X-ray showed bone cement of L4 vertebra was uniformly dispersed when discharged from hospital three days following operation (Figure 2A and B). While there was recurrent pain in the lumbosacral region with intermittent fever and fatigue two weeks after the procedure, her core temperature was up to 37.9 C. This patient's symptoms were progressively aggravated with radiation pain of both lower extremities, especially in the left lower extremity, during 4-month anti-inflammatory and analgesic treatment. Thus, she came to the orthopedic department of our hospital.
Medical history showed the patient ate mutton while traveling in the epidemic area one week before vertebroplasty. Due to severe low back pain, she was unable to stand. Percussion pain of the lower lumbar and paraspinal regions was obvious, radiating to both lower limbs. There was hyperesthesia on the posterolateral thigh and anterior medial leg of the lower extremities, with the left side being more affected than the right. Motion in the lumbar region was constrained both actively and passively. Muscle strength of bilateral quadriceps femoris and extensor pollicis longus was grade 4. The femoral nerve stretch test, straight leg raise test, and Braggard's test were all positive on both sides. Thus, we suspect there was a great possibility of spinal infection, and further blood tests showed WBC 3.80x109/L with neutrophils accounting for 85.51%, ESR 32mm/hr, CRP 25.8mg/L, negative T-SPOT. TB assay (T-SPOT) and positive serum agglutination test (SAT) at a titer of 1:800.
An X-ray, computerized tomography (CT) scan, and MRI of the spine were performed to determine the spinal segment affected. X-ray showed narrow intervertebral disc spaces at L3/4 and L4/5, and the osteophyte at the vertebra edge of L3-L5 proliferated obviously (Figure 2C and D). CT scan showed multiple destructive changes at L4 and L5 vertebra with paravertebral and intraspinal abscess formation around L4 vertebra (Figure 3A-D). MRI revealed hypointense signal of L3-L5 vertebra on T1WI of which T2WI demonstrated mixed intensity signal and FS-T2WI showed hyperintense signal (Figure 3E-H) consistent with infectious spondylitis with intraspinal abscess.
During hospitalization, antibiotics were administered, including rifampicin (0.6g po qd), doxycycline (0.1g po bid), and cefotaxime-sulbactam (2.25g ivgtt q8h). When empiric antibiotics were ineffective for two weeks, posterior focus debridement with decompression, fusion and internal fixation was performed, and large amounts of intraspinal and paraspinal purulent fluid were apparent during the procedure (Figure 4A), of which real-time polymerase chain reaction (Real-time PCR) test revealed Brucella melitensis (B. melitensis). The postoperative pathological results of the intervertebral disc of L3/4 and L4/5 (Figure 4B) demonstrated that organisms consistent with Brucella were present by Giemsa staining and Mycobacterium tuberculosis was not present by negative acid-fast staining (Figure 5A and B).
After being discharged from the hospital ten days following the surgery, this patient experienced significant pain relief in the lumbosacral region and low extremities. The femoral nerve stretch test, straight leg raise test, and Braggard's test on both sides all turned negative. The patient experienced a significant decline in infection indexes. X-ray showed postoperative changes of instrumentation placement (Figure 2E and F). Anti-brucellar medications were adjusted to rifampicin (0.6g po qd) and doxycycline (0.1g po bid) after discharge; the entire course of antibiotics treatment was half a year. Her discomforts wholly disappeared, and muscle strength of lower extremities was grade 5 at the last follow-up twelve months after discharge. The infection indexes all turned normal, and the titer of SAT dropped to 1:100. X-ray showed no abnormal changes in spinal instrumentation placement (Figure 2G and H); CT scan and MRI also demonstrated no abnormity (Figure 6A-H).