Case Report: Renal rupture and massive urine extravasation following flexible ureteroscopic lithotripsy: analysis of 4 cases and literature review.

A retrospective analysis was conducted on 4 patients who developed renal rupture and urinary extravasation after retrograde intrarenal surgery (RIRS) in our hospital. Their clinical data, intraoperative findings, rescue procedures, and outcomes were reviewed, alongside a narrative literature review of relevant studies. For the literature review, we searched PubMed and CNKI databases using the terms "RIRS," "renal rupture," "urinary extravasation," "intrarenal pressure," and "ureteroscopic complications," without applying strict systematic selection criteria. Because these cases were collected over an extended period without a dedicated procedural registry, we did not attempt to calculate the overall incidence of this complication at our institution; rather, this series focuses on the clinical presentation, risk factors, and management strategies. We acknowledge that the small sample size, retrospective single-center design, and absence of a control group are inherent limitations of this case series. All 4 cases were successfully managed without mortality. The primary contributing factors included pre-existing moderate-to-severe hydronephrosis with thinning of the renal parenchyma (n = 4), duplicated kidney (n = 1), prior renal surgery (n = 2), prolonged operative time (2.5 to 3.7 h), presumed elevated intrarenal pressure (inferred from poor outflow and prolonged operative time), and pre-existing urinary tract infection (n = 1). Emergency interventions comprised broad-spectrum antibiotics, fluid resuscitation, percutaneous drainage of ascites (1,000-1,200 mL drained within 30 min in relevant cases), and selective renal artery embolization for active bleeding (n = 1). All patients recovered and were discharged; follow-up imaging showed gradual resolution of perinephric hematoma and extravasation. Renal rupture with massive urinary extravasation is a rare but severe complication of RIRS. Key preventive measures, as suggested by the published literature, may include strict case selection, adequate preoperative infection control, preoperative ureteral stenting (generally for 7-14 days according to prior reports), efforts to keep intrarenal pressure below the commonly cited threshold of 30 mmHg, and limiting operative time to the generally recommended 60-90 min, alongside early intraoperative or postoperative detection via ultrasound or CT. This series underscores that early recognition, multidisciplinary collaboration, and timely intervention, including prompt drainage, intensive care support, and selective arterial embolization when indicated, are critical for successful management.