Prediction of postoperative SSIs and causative organisms in the spine by measuring trophic factors using preoperative serum markers.

Abstract

Background: Surgical site infection (SSI) following spinal surgery, although rare, is a serious complication that affects patient outcomes. Identifying risk factors such as patient background, preoperative serum markers, and surgical factors is essential for effective screening and prevention measures. Therefore, this study aimed to verify whether preoperative patient conditions serve as predictors of post-spinal surgery infections and to determine the association between preoperative serum markers and infecting pathogen species.

Methods: This single center retrospective study analyzed 427 patients who underwent spinal surgery at our hospital between November 2019 and September 2022. Data on patient demographics, comorbidities, preoperative blood tests, surgical factors, SSI occurrence, and causative organisms were collected. Logistic regression analysis was performed to identify independent predictors of SSI, and a subgroup analysis compared preoperative serum markers between superficial and intra-abdominal bacterial infections.

Results: SSI occurred in 33 patients (7.7 %). Several factors showed significant differences between the SSI and non-SSI groups, including albumin (ALB), Albumin-Globulin Ratio (AGR), Prognostic Nutritional Index (PNI), C-Reactive Protein (CRP), CAR, D-dimer, and blood loss. Logistic regression analysis identified ALB as the only independent predictor of SSI (OR = 0.23, 95 % CI: 0.11-0.48, P < 0.001), with a cutoff value of <4.0 g/dL. Among SSI cases with identified pathogens, 17 were caused by skin commensal bacteria, while 7 were attributed to intra-abdominal comm-ensal bacteria. Subgroup analysis revealed that AGR and Lympocyte to Monocyte Ratio (LMR) were significantly higher in the intra-abdominal infection group than in the superficial infection group (P = 0.028 and P = 0.045, respectively).

Conclusion: Preoperative ALB levels serve as a crucial predictor of postoperative SSI in spinal surgery, with a cutoff value of <4.0 g/dL. Additionally, the type of bacterial infection (superficial vs. intra-abdominal) may be influenced by preoperative patient factors.