Clinical Outcomes in Older Patients Aged over 75 Years Who Underwent Early Surgical Treatment for Pyogenic Vertebral Osteomyelitis

Older patients with pyogenic vertebral osteomyelitis (PVO) usually have more medical comorbidities compared with younger patients, and present with advanced infections from different causative organisms. To aid surgical decision-making, we compared surgical outcomes of older patients with PVO to those who underwent nonoperative treatment. We identified the risk factors for adverse post-operative outcomes, and analyzed the clinical risks from further spinal instrumentation. This retrospective comparative study included 439 patients aged ≥75 years with PVO. Multivariable analysis was performed to compare treatment outcomes among three groups: 194, 130, and 115 patients in the non-operative, non-instrumented, and instrumented groups, respectively. The risk factors for adverse outcomes after surgical treatment were evaluated using a logistic regression model, and the estimates of the multivariable models were internally validated using bootstrap samples. Recurrence and mortality of these patients were closely associated with neurologic deficits, and increased surgical invasiveness, resulting from additional spinal instrumentation, did not increase the risk of recurrence or mortality. We propose that surgical treatment for these patients should focus on improving neurologic deficits through immediate and sufficient removal of abscesses. Spinal instrumentation can be performed if indicated, within reasonable clinical risk.

Use of Blood Culture Bottles to Incubate Irrigation Water from the Surgical Site May Improve Detection of Causative Organisms in Pyogenic Vertebral Osteomyelitis

【Background】 Identification of pathogenic microorganisms are essential for pyogenic vertebral osteomyelitis (PVO). This study aimed to demonstrate the effectiveness of the blood culture bottle (BCB) system in identifying PVO causative organisms. 【Materials & Methods】 We analyzed retrospectively collected data from patients who underwent full-endoscopic spine surgery for PVO between January 2016 and March 2019. Irrigation water generated in the surgical field was incubated in the BCB system, and compared with blood culture before surgery and tissue culture taken by the conventional method. The microbial identification rate and the time from sample collection to microbial identification of the BCB system were compared with conventional blood culture and tissue cultures using the Wilcoxon signed-rank test. 【Results】 We included 17 patients (12 men, five women; mean age, 72.8 ± 11.9 years). Bacteria were cultured from 3 (17.6%), 13 (76.5%), and 12 (70.6%) patients by blood culture, tissue culture, and the BCB system, respectively. Tissue culture and the BCB system had significantly higher detection rates than blood culture (P = .002, P =.003), and there was no significant difference between tissue culture and BCB system (P = .655). In 15 cases (88.2%), the causative organism was identified by at least one method. In two cases, the causative organism (Escherichia coli) was only identified by the BCB system. The BCB system required amount of time for microbial identification (3.9 ± 3.0 days), compared with the time required for blood culture (5.0 ± 1.4 days, P =.180) and tissue culture (11.9 ± 15.1 days, P =.012). 【Conclusions】 Results suggest the possibility of improving the detection rate and time to detection of causative organisms by the BCB system as an adjunct to the conventional method.

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

Backgroundand objectives: The clinical assessment of therapeutic response in pyogenic vertebral osteomyelitis (PVO) has been usually performed based on the changes of clinical symptoms and blood inflammatory markers. Recently, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has emerged as an alternative independent method. We analyzed the validity of the clinical assessment for detecting residual PVO based on 18F-FDG-PET. Materials and Methods: This study was conducted with 53 patients confirmed as lumbar PVO under retrospective design. All patients underwent clinical assessment using clinical symptoms and C-reactive protein (CRP) for therapeutic response after parenteral antibiotic therapy, which led to the decision of placement in the uncontrolled (group UC) or controlled (group C) group. The validity of clinical assessment was analyzed based on the cut-off values of FDG uptake for detecting residual PVO as references, which are already established in the previous literature. Results: The mean duration of parenteral antibiotic therapy and recurrence rate were 42.19 ± 15.84 (21–89) days and 9.4% (5/53), respectively. 18F-FDG-PETs were performed at 80 rounds of clinical assessment on 37.40 ± 13.15 (21–83) days of parenteral antibiotic therapy and divided: 31 into group UC and 49 into group C, according to the decisions of clinical assessment. Based on the cut-off values of FDG uptake, clinical assessment showed 48.4–58.1% of false positive for residual PVO in group UC. However, 18F-FDG-PET showed 8.2% (4/49) of false negative for residual PVO in group C, which led to recurrences. Conclusions: Clinical assessment using clinical symptoms and CRP for evaluating therapeutic response in PVO is still a useful method in terms of similar recurrence rate compared to 18F-FDG-PET. However, the high rate of false positive for residual PVO can prolong the use of unnecessary antibiotics and overall treatment period.

Clinical and Radiological Features Predicting Intervertebral Autofusion after Successful Antibiotic Therapy in Pyogenic Vertebral Osteomyelitis

Background: Pyogenic vertebral osteomyelitis (PVO) is a bacterial infection involving the intervertebral disc, vertebral body, and paravertebral soft tissues. Damaged intervertebral structure is a major cause of persistent back pain even after successful antibiotic therapy, which can be improved by achieving autofusion or via additional surgical fixation. In this study, we analyzed the clinical and radiological features predicting intervertebral autofusion after successful antibiotic therapy in lumbar PVO. Methods: This study was retrospectively conducted with 32 patients (20 men and 12 women) diagnosed with lumbar PVO that was completely cured with no recurrences after antibiotic therapy. They were divided into two groups with (group A, n = 18) and without (group B, n = 14) intervertebral autofusion at six-month follow-up. Differences in back pain, blood inflammatory markers, and radiological features of PVO on simultaneous 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG-PET/MRI) of the intervertebral structure between the two groups were analyzed. Results: The mean duration of antibiotic therapy was 41.44 ± 14.21 (21–89) days. Group A showed a statistically higher erythrocyte sedimentation ratio (ESR; 59.28 ± 32.33 vs. 33.93 ± 18.76 mm/h, p = 0.014; normal range of ESR < 25), maximum standardized 18F-FDG uptake (SUVmax; 5.56 ± 1.86 vs. 3.98 ± 1.40, p = 0.013), and sustained extensive edematous changes on T2-weighted fat saturation (T2FS) MRI (p = 0.015) immediately after successful antibiotic therapy. However, no significant differences were observed in back pain, C-reactive protein, or the distribution of 18F-FDG uptake/contrast enhancement on 18F-FDG-PET/MRI (p > 0.05). Conclusions: Higher ESR and SUVmax of the intervertebral structure and sustained extensive edematous change on T2FS MRI immediately after successful antibiotic therapy are related with subsequent intervertebral autofusion, which should be carefully considered when assessing therapeutic response in PVO.

EARLY IMAGING AND COURSE-OF-DISEASE CONTROL MARKERS OF PYOGENIC VERTEBRAL OSTEOMYELITIS

Background. The diagnosis of early pyogenic vertebral osteomyelitis is essential for prompt determination of treatment strategy and prevention of suppurative-destructive complications, although the nonspecifi c clinical manifestation obstructs timely disease detection. Aim. To analyse the clinical accuracy of various radiological imaging methods for early detection and control over vertebral osteomyelitis course Materials and methods. A retrospective study of standardized clinical data of patients (N = 54) who underwent treatment at the Neurosurgery Department of the MМCC WR between 2010 and 2020 was carried out. Patients were observed for 12–36 months. Study fi ndings and discussion. Our study revealed that during radiological imaging, infl ammatory changes in the vertebrae specifi c to osteomyelitis were not found in any case, which signifi cantly delays the diagnosis. The study analysed and grouped radiological signs of the infl ammatory process spread in the vertebrae in case of spondylodiscitis by CT and MR stages. Spondylodiscitis was diagnosed by CT of the spine in the late third stage only in 29.0 % of patients. Nonspecifi c destructive changes of vertebrae were detected in 51.6% of persons, which required additional MRI examination to establish the diagnosis. In 19.4% of those examined in the presence of the fi rst MR stage, no specifi c CT signs of osteomyelitis were found. MRI scan of the spine is the main specifi c (93 %), accurate (94 %) and sensitive (97 %) method for early detection of pyogenic osteomyelitis. Although according to the world literature, MRI is not sensitive enough to assess the dynamics of the infl ammatory process in the spine, the progressive increase in signal intensity of vertebral cortex on T1-weighted images within aff ected vertebrae correlates well with infl ammation resolving and C-reactive protein (CRP) level normalization. We described this radiological sign as a «vertebral rim» phenomenon (VRP). In our study, a reliable correlation was found between CRP level and the «vertebral rim» phenomenon on MRI. Conclusions. For early detection of pyogenic vertebral osteomyelitis, MRI examination is the main specifi c and sensitive method. We suggest combining the CRP level and «vertebral rim» sign in practice as dynamics of spondylodiscitis markers and justifi cation of antibacterial therapy strategy.

Interest of Follow-Up Radiological Imaging in Patients with Pyogenic Vertebral Osteomyelitis

No recommendations are established for monitoring pyogenic vertebral osteomyelitis (PVO). Thus, the realization of systematic follow-up radiological imaging is controversial. The objective of this study was to evaluate the interest in follow-up radiological imaging in patients with PVO. We conducted a retrospective cohort analysis of patients with PVO who had both baseline and follow-up radiological imaging. We classified the follow-up images into two groups, improvement/stability, and deterioration, compared with the baseline data. For each patient, we compared their radiological imaging follow-up to their clinical-biological condition assessed at the same time. Eighty-six patients were included. The mean age was 68 years (±13). A total of 99 radiological imaging examinations at diagnosis and at follow-up were analyzed, 69 Magnetic Resonance Imaging (MRI), and 30 Computerized Tomography (CT scans). The mean delay between the follow-up radiological imaging and clinical evaluation was 2.8 +/− 2.1 months. Of the 36 patients with clinical and biological recovery, 24 patients (67%) had improved radiological imaging and 12 patients (34%) had radiological worsening (new abscesses (n = 4), extension of soft tissue infiltration (n = 2) and/or epiduritis (n = 2) or appearance of new locations (n = 1)). Among the 50 patients considered as unhealed, on the contrary, radiological imaging showed an improvement in imaging in 39 patients (78%) and a worsening in 11 patients (22%). Our study showed that there was no correlation between the clinical condition of patients and their follow-up radiological imaging in the context of PVO.