Identifying and Mitigating SIRS in Patients Undergoing Percutaneous Nephrolithotomy

Urolithiasis, commonly known as kidney stones, affects approximately 5 to 10% of the global population at some point in their lives. This condition can significantly diminish quality of life and recurs in more than half of the affected individuals. One of the primary treatments for kidney stones, particularly large or complex stones, is percutaneous nephrolithotomy (PCNL). While PCNL is effective, it carries a higher risk of complications like infections, which can lead to serious conditions such as sepsis.

What is Systemic Inflammatory Response Syndrome (SIRS)?

SIRS is an inflammatory response condition that can occur after infections, including those resulting from PCNL. It is characterized by fever, tachycardia, increased respiratory rate, and altered mental status. SIRS is the initial phase of the sepsis cascade and can progress to full sepsis if left untreated. Sepsis complicates approximately 18% to 28% of PCNL cases, making early detection and intervention crucial.

Preoperative Inflammatory Biomarkers and SIRS Risk

Studies have highlighted the utility of preoperative inflammatory biomarkers like NLR (Neutrophil-to-Lymphocyte Ratio), PLR (Platelet-to-Lymphocyte Ratio), LMR (Lymphocyte-to-Monocyte Ratio), and SII (Systemic Immune-Inflammation Index) in predicting the risk of SIRS. These markers are widely accessible, easy to measure, and inexpensive, making them valuable tools in clinical practice.

Methodology

This study analyzed 317 patients who underwent PCNL at the Anhui Medical University First Affiliated Hospital between January 2018 and June 2024. Patients were grouped based on whether they developed SIRS postoperatively. Data was collected on patient demographics, comorbidities, preoperative laboratory values, and stone characteristics. The study used statistical analysis to identify significant risk factors and the predictive power of inflammatory biomarkers.

Clinical Data

Patient data included age, BMI, clinical history, and laboratory parameters like NLR, PLR, LMR, and SII. Stone size, type (staghorn or non-staghorn), and operation time were also evaluated. Preoperative examinations such as renal-ureter-bladder radiography (KUB), ultrasonography, and computed tomography (CT) were conducted to assess kidney stone characteristics.

Surgical Procedure

Patients were positioned in lithotomy and then prone positions. Under ultrasonographic guidance, a renal calyx was punctured, and an 18 Fr sheath was inserted. The Holmium laser was used to fragment stones, followed by their removal using stone forceps and a pulsed perfusion pump. After the procedure, a double-J catheter and nephrostomy tube were placed.

Statistical Analysis

Statistical analysis was performed using SPSS software. The Kolmogorov-Smirnov test determined data distribution. Chi-square and Fisher’s exact tests analyzed categorical variables, while t-tests and Mann-Whitney U tests evaluated numerical variables. Univariate and multivariate logistic regression analyses identified risk factors for SIRS. Receiver Operating Characteristic (ROC) curves and area under the curve (AUC) values assessed the predictive value of inflammatory biomarkers.

Results

Univariate analysis revealed several significant predictors of SIRS, including female gender, operation time, blood leukocyte count, neutrophil level, monocyte concentration, urine leukocyte count, urine nitrite, urine culture results, and systemic inflammation indices—NLR, PLR, LMR, and SII.

Figure 1 ROC curves for neutrophil-to-lymphocyte ratio (NLR) (A), platelet-to-lymphocyte ratio (PLR) (B) and Systemic immune-inflammatory index (SII) (C) to predict SIRS. ROC = receiver operating characteristic.

Discussion

The study identified female gender, preoperative urine cultures, and longer operation times as risk factors for SIRS after PCNL. Women are more susceptible to infections due to anatomical features and hormonal changes. The occurrence of SIRS with negative urine cultures may be attributed to bacterial endotoxins in infected stones. High NLR, PLR, or SII indicates a higher risk of SIRS, especially in patients with negative cultures.

Conclusions

NLR, PLR, and SII are valuable, readily available, and clinically feasible predictors of SIRS after PCNL. These biomarkers can aid in identifying high-risk patients preoperatively. High-risk individuals should receive prophylactic antibiotics and aggressive anti-infective treatment during surgery. Further research is needed to confirm the predictive accuracy of these markers.

Abbreviations

SIRS, Systemic inflammatory response syndrome; PCNL, Percutaneous nephrolithotomy; NLR, Neutrophil to lymphocyte ratio; LMR, lymphocyte to monocyte ratio; PLR, Platelet to lymphocyte ratio; SII, Systemic immune inflammation, platelet count × neutrophil count / lymphocyte count; IQR, Interquartile Range.

Ethics Approval and Informed Consent

This retrospective study was conducted under the strict confidentiality of patient information and adhered to the Declaration of Helsinki. The ethics committee of the Dongcheng branch of Anhui Medical University approved the study.

Funding

The study was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Anhui Province.

Disclosure

The authors have declared no conflicts of interest.

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