Clinical and Radiological Analysis of Pyogenic Vertebral Osteomyelitis Immediately after Successful Antimicrobial Therapy: Considerations for Assessing Therapeutic Response

Abstract

Purpose: The clinical and radiological abnormal findings continue even after successful treatment in pyogenic vertebral osteomyelitis (PVO). We analyzed the clinical and radiological features of cured PVO based on 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (FDG-PET/MRI) and compared the radiological differences between FDG-PET and MRI for assessing therapeutic response in PVO. Methods: This study included 43 patients (28 men and 15 women) with lumbar PVO who had no recurrence after successful antimicrobial therapy. They were divided into two groups based on the location of maximum standardized FDG uptake value (SUVmax) of PVO lesion on FDG-PET/MRI when parenteral antibiotics were discontinued (31 in group A: Intervertebral structure; 12 in group B: Vertebral body and paravertebral muscle). The differences of clinical symptoms, hematological inflammatory indices, and radiological features were retrospectively analyzed. Results: The patients were treated with 42.28 ± 14.58 (21–89) days of parenteral antibiotics. There were significant differences in C-reactive protein (0.97 ± 1.10 vs. 0.51 ± 0.31 mg/dL, p = 0.041; normal range of CRP < 0.5), back pain (4.29 ± 1.13 vs. 3.50 ± 1.00, p = 0.040; visual analog scale), and SUVmax (4.34 ± 1.24 vs. 5.89 ± 1.57, p < 0.001) between the two groups. In the distribution pattern of PVO lesions, FDG-PET overall showed recovery pattern earlier than MRI did (p < 0.001). Conclusions: In cured PVO, the clinical features vary depending on the location of major structural damage of PVO lesion. The involvement of intervertebral structure is related with sustained back pain and elevation of CRP, and vertebral body/paravertebral muscle shows favorable clinical features despite advanced structural damages.

Clinical characteristics of pyogenic vertebral osteomyelitis, and factors associated with inadequate treatment response

“…In accordance with other studies, the majority of our PVO population was found to consist of elderly men presenting with back pain and elevated CRP (Chang et al, 2018;Chong et al, 2018;Jeon et al, 2020;Kim et al, 2020;Vettivel et al, 2019). These findings were consistent with a previous study from our institution by Aagaard et al, using a similar design, on 100 PVO patients admitted from 2006 to 2011 (Aagaard et al, 2013).…”

“…In general, our study reported similar demographics and comorbidities to those in previous reports (Chong et al, 2018;Jeon et al, 2020;Kim et al, 2020;Lee et al, 2019).…”

Validity of Clinical Assessment Using Clinical Symptoms and C-Reactive Protein for Therapeutic Response in Pyogenic Vertebral Osteomyelitis: Analysis Based on 18F-FDG-PET

“…Jeon et al [ 14 , 15 ] investigated the change of FDG uptake according to the phases of osteomyelitis based on the pathophysiological features of osteomyelitis. The early phase of PVO is characterized by activated neutrophil accumulation, known as the respiratory burst, which uses greater amounts of glucose as the main energy source for chemotaxis and phagocytosis [ 23 ].…”

“…Furthermore, they emphasized the increase of diagnostic accuracy for detecting residual PVO using 18 F-FDG-PET and CRP together. In addition, the clinical and radiological characteristics according to anatomical location of major structural damage were analyzed in patients with cured PVO, which was expected to be very helpful for determining therapeutic response in clinical field [ 15 ].…”

Antimicrobial therapy and assessing therapeutic response in culture-negative pyogenic vertebral osteomyelitis: a retrospective comparative study with culture-positive pyogenic vertebral osteomyelitis

“…Elevated erythrocyte segmentation rate (ESR, normal range: < 25 mm/h) or C-reactive protein (CRP, normal range: < 0.5 mg/dL) level or both along with speci c magnetic resonance (MR) ndings of PVO as a contiguous single lesion was an important clue for the diagnosis of PVO. In the extent of PVO lesion, a PVO lesion comprises the upper and lower vertebrae centering on the infected disc with or without epidural, psoas, and paraspinal abscesses; it was de ned as one level (e.g., if there were two infected discs, then three vertebrae were included centering on the two infected discs, this PVO lesion was considered two levels) [9] .…”