Neutrophil-Lymphocyte Ratio and Lymphocyte-Monocyte Ratio correlate with Chronic Prosthetic Joint Infection but are not useful markers for diagnosis.

PURPOSE: To investigate reported correlations between Neutrophil-to-Lymphocyte (NLR) and Lymphocyte-to-Monocyte (LMR) ratios and their value in diagnosis of chronic prosthetic joint infection (PJI) in a large cohort of patients from a single specialist hospital. METHODS: Diagnostic aspirations of 362 patients under investigation for PJI were identified. Of the included patients 185 patients received a final diagnosis of PJI and 177 were classed as aseptic. Established criteria (ICM 2018) were employed to define PJI. Included in the analysis are differential white cell counts, C-Reactive Protein (CRP), Synovial Leukocyte Count, Synovial Alpha-defensin ELISA and Synovial Leukocyte esterase activity. Receiver-operator characteristic (ROC) curves were calculated for each of the available diagnostic tests together with the corresponding area under the curve values (AUC). Youden's index was utilized to identify the optimal diagnostic threshold point for the NLR and LMR. Other diagnostic tests were evaluated as per the threshold values previously defined in the literature and specified in the ICM criteria. RESULTS: Using Youden's Index to identify the optimal NLR cut-off within our cohort we established a value of 2.93. This yielded a sensitivity of 0.60 and specificity of 0.64. The area under the curve (AUC) of a receiving operator characteristics (ROC) curve was 0.625. Regarding the LMR the results demonstrate similar findings; a positive correlation with a diagnosis of infection but poor sensitivity and specificity. The AUC for LMR was 0.633 and was not superior to NLR (P = 0.753). CONCLUSIONS: There is a significant correlation between higher Neutrophil-Lymphocyte and Lymphocyte-Monocyte ratios, and a diagnosis of PJI. The sensitivity and specificity of this calculation is poor and the does not add value to the diagnostic algorithm for PJI. LEVEL OF EVIDENCE: Level III Retrospective Cohort analysis.

Total en bloc spondylectomy in the treatment of postoperative chronic osteomyelitis: a case report.

Background: Infection of the spine after surgical procedures is one of the most dreaded complications of spinal fusion surgery. Treatment goals are to eradicate the necrotic and infected tissue and to obtain a correct spinal profile. Traditionally many authors have recommended the posterolateral or double approach, anterior and posterior. Total en bloc spondylectomy is a surgical procedure traditionally used to treat primary and metastatic tumors. The use of this surgical procedure in treatment of chronic vertebral osteomyelitis is not clearly defined in literature. Case Description: This case involved a 66-year-old female patient with a history of T9-S1 instrumentation after several surgeries, who developed chronic osteomyelitis of T8-T9 with extensive destruction of the vertebral body and severe thoracic kyphosis. After targeted antibiotic therapy, total en bloc spondylectomy of T8-T9 was performed according to the Tomita technique. Necrotic and infected tissues were removed proceeding as if it were chronic osteomyelitis of long bones and performing en bloc resection with clear margins, that is, applying the criteria of oncological surgery to this chronic infection. After resection, the sagittal plane is reconstructed in the affected segment, restoring the normal distance between the two healthy vertebrae and the mechanical stability of the spine. Conclusions: Total en bloc spondylectomy in the treatment of extensive infectious lesions with a mechanical component allows performing en bloc resection of infected and necrotic tissue along with biological and mechanical reconstruction. In our case, the complete resection of the infected bone and soft tissues achieved good outcome without complications. We propose total en bloc spondylectomy as a reasonable treatment option in complicated spondylodiscitis progressing to extensive chronic osteomyelitis and compromising spinal stability due to a significant loss of bone material.