Perioperative predictors of urinary tract infections after percutaneous nephrolithotomy

Abstract

BACKGROUND

Urinary tract infections (UTIs) are the most common postoperative complications of percutaneous nephrolithotomy (PNL). Besides the significant threat to the patient's life, they represent a surgical, financial, and stressful burden to the healthcare systems. Duration of the procedure, bacterial load in urine, severity of obstruction, and presence of infected stone directly increase the incidence of UTI.

AIM

To identify the perioperative predictors of postoperative UTIs in patients undergoing PNL in Assiut University Urology Hospital, Assiut, Egypt.

METHODS

A prospective study was conducted at Assiut University Urology Hospital, Assiut University, Egypt, involving adult patients who underwent PNL from May 2022 to March 2023 for postoperative UTI. The sample size was calculated based on the previous studies and the PNL rate in our hospital, using Thompson’s equation. Patients who had other surgical procedures besides PNL, had immunosuppression, congenital kidney malformations, or refused to participate were excluded. Patients were recruited consecutively during the study duration. The Excel sheet was used for data collection, and the Statistical Package for the Social Sciences (SPSS) program, version 26, was used for statistical analysis. The authors analyzed the preoperative, operative, and postoperative variables using both univariate and multivariate analyses. The statistical cutoff point for significance was set at P < 0.05.

RESULTS

This study included 157 patients: 96 (61.1%) males and 61 (39.9%) females. The mean ± SD (range) age was 47.37 ± 12.47 (20-65) years. The mean body mass index ± SD (range) was 24.44 ± 2.84 (16.80-33.80) kg/m². Thirty-one patients (19.7%) had postoperative UTIs. The univariate analysis revealed that the presence of a history of pyuria (P = 0.026), diabetes mellitus (P = 0.010), large stone size (P < 0.001), multiple renal punctures (P = 0.001), prolonged operative time (P = 0.004), placement of a double-J stent (P = 0.027) or nephrostomy tube (P = 0.021), higher blood transfusion rate (P = 0.024), residual stones (P = 0.002), and prolonged urethral catheterization (P = 0.001) were associated with the incidence of UTIs. The multivariate analysis demonstrated that the presence of diabetes mellitus [odds ratio (OR) = 0.15, confidence interval (CI): 1.1-4.41], stone size (OR = 2.15, CI: 0.14-1.13), and residual stone (OR = 0.16, CI: 0.03-0.93) were independent predictors for postoperative UTIs.

CONCLUSION

Thirty-one out of 157 patients experienced UTIs following PNL. The presence of diabetes mellitus, larger stone size, and residual stones were identified as independent risk factors for postoperative UTIs after PNL. We suggest conducting further research to identify factors that may aid in the early detection of post-PNL UTI risks.

Keywords: Percutaneous nephrolithotomy; Perioperative predictors; Postoperative complications; Urinary tract infections; Urolithiasis

Core Tip: Percutaneous nephrolithotomy is the preferred treatment for kidney stones larger than 2 cm. It offers faster recovery and a higher stone removal rate. However, its complication profile remains significant, including hemorrhage and urinary tract infections. The current prospective study identified factors such as diabetes mellitus, history of preoperative pyuria, large stone size, multiple punctures, long operative time, intraoperative double-J stent placement, blood transfusion, residual stones, and extended urethral catheterization as influencing the risk of post-percutaneous nephrolithotomy urinary tract infection. Nonetheless, diabetes mellitus, larger stone size, and residual stones were independent predictors.