This study looks at two ways to treat kidney stones that are 2-3 cm big. The first method is called RIRS (Retrograde Intrarenal Stone Surgery). It's a common way to treat kidney stones using a special tool called a ureteral access sheath, which is like a tiny flexible tube. The second method is called PCNL (Percutaneous Nephrolithotomy), which involves making a small cut in the skin to remove the stones. The study compares how safe and effective these two methods are when using a new type of ureteral access sheath that controls pressure.

• Participants need to be at least 18 years old and have kidney stones 2-3 cm in size.
• Those with abnormal urinary tract shapes or infections cannot join.
• This study is observational, so no treatments are given, and there's no mention of compensation or risks.

This study helps determine the best way to treat medium-sized kidney stones. People who join must understand and agree to the study rules.