Percutaneous nephrolithotomy among patients with upper urinary system anomalies: evaluating the prevalence, types, characteristics and comparing its outcomes with other patients: a prospective, comparative study of 1485 patients.

background and purposePCNL plays an important role in the treatment of kidney stones, but since it is less defined for patients with anomalous urinary system, their management is challenging. This study attempts to resolve this issue to help the urologist to properly assess the patients before, during, and after surgery. MATERIALS AND

methodsA prospective study data were collected for 1485 PCNL candidates treated over 3 years (Sep 2022-Dec 2025). According to preoperative and intraoperative imaging, the samples were divided into two groups: abnormal (n = 121) and normal (n = 1364) groups and compared.

resultsThe prevalence of anomalies was 8.1%, with bifid or trifid pelvis 4.5%, mal-rotation 1.3%, duplex system 1.1%, infundibulum stenosis 0.5%, and horseshoe kidney 0.4% being the most common, and others being rare. In the anomaly group, the stones were mostly mixed (73.5%) with a dominant calcium component. Uric acid and struvite types were slightly more common than in the normal group. There was no statistically significant gender difference between the two groups. (P = 0.54) The mean age of the normal group was 40.8 ± 8.6 years and the anomaly group was 37.9 ± 8.8 years. The mean length of hospitalization in the anomaly group was 3.60 ± 0.89 days which was significantly longer than the normal group (P < 0.0001). There was no difference in body mass index (BMI) between the groups (P = 0.144). In the anomaly group, 84.3% had a history of related procedures. Number of access in the anomaly group was more than in the normal group (1.09 ± 0.28 vs. 1.18 ± 0.39 and P = 0.01). There were more upper access and puncture sites. In the anomaly group, the surgical duration was 66.5 ± 28.1 min, which was more than in the normal group. (P = 0.0003) In the anomaly group, 73.6% were stone-free in the first operation, compared to 82.2% in the normal group. (P = 0.019) Postoperative complications in the anomaly group occurred in 47.1% and more than in normal individuals, but major complications in the anomaly group were comparable to the normal group. (P = 0.43).

conclusionTypes of urinary system anomalies and their prevalence in PCNL candidate patients and postoperative outcomes indicate the importance of the subject. It seems necessary to achieve appropriate criteria for comparison and correct understanding of future studies. Ultimately, PCNL in patients with upper urinary tract anomalies is associated with increased technical complexity, reduced stone-free rates, and higher overall complication rates. Although it remains a viable treatment modality, these outcomes should be carefully considered during preoperative counseling and surgical planning.