Ureteral Obstruction

Obstructive uropathy is a serious complication frequently seen in cancer patients, occurring when urine flow from the kidneys is blocked by tumor compression, invasion, or benign etiologies such as radiation-induced strictures and stones. If left untreated, this blockage leads to hydronephrosis, acute kidney impairment, and interruptions in cancer therapy. When internal ureteral stenting fails or is not possible, percutaneous nephrostomy (PCN), which involves inserting a small drainage tube through the back directly into the renal collecting system, is required to decompress the kidney and preserve renal function. Traditionally, PCN is performed under fluoroscopy, exposing patients and healthcare staff to ionizing radiation. Ultrasound guidance provides continuous real-time visualization of the renal structures while completely eliminating radiation hazards. The primary purpose of this prospective interventional study is to evaluate the technical success, safety, and complication rates of ultrasound-guided percutaneous nephrostomy in oncology patients presenting with urinary tract obstruction. Participants in this study undergo ultrasound-guided PCN under local anesthesia using the standard Seldinger technique to place an 8Fr pigtail drainage catheter. The study evaluates the technical success rate of the procedure, procedural and post-procedural complications (such as bleeding or sepsis), recovery of kidney function measured by changes in serum creatinine levels, and hospital length of stay.

The goal of this observational study is to investigate the systemic pathogenesis and identify potential diagnostic biomarkers in patients with ureteral stricture and healthy volunteers. The main questions it aims to answer are: What are the systemic differences in the gut microbiome, urine microbiome, and metabolomic profiles (fecal, urinary, and serum) between patients with ureteral stricture and healthy controls? What are the correlations between these microbial/metabolic alterations and clinical phenotypes, such as stricture severity, inflammatory levels, and renal function? Researchers will compare the biological panoramic profiles of patients with ureteral stricture to those of healthy controls to see if specific "microbiome-metabolite-disease" regulatory networks drive the development of the condition. Participants will: Provide stool samples for gut microbiome (16S/Metagenomics) and metabolomic analysis. Provide urine samples for urine microbiome and metabolomic analysis. Provide blood (serum) samples for systemic metabolomic profiling. Undergo clinical assessments, including medical history collection, imaging (e.g., CT/IVP), and laboratory tests (e.g., renal function, inflammatory markers) to evaluate disease severity.