What is the popular ureteroscopic stone extraction procedure in recent years for the treatment of kidney stones? Why is there a difference between ureteroscopy rigid and fiberoptic ureteroscopy? What are the advantages and disadvantages of this procedure compared with traditional surgery? The human urinary system has a natural lumen, the urethra, which leads directly to the outside of the body and does not have to be artificially created. Ureteroscopy is designed to reverse the process of urination: we all know that urine is discharged from the urethra, and from the urethra up to the bladder, and from the bladder up to the ureter, and from the ureter up to the kidneys, where the stones originate. If a surgical mirror is sent in by this route, and this mirror can turn and adapt to the complex structure of the human body, and follow the normal physiological curvature to reach the kidney, then the kidney stone can be removed. This is now a relatively new technique of fiberoptic ureteroscopy for lithotripsy, which is the least invasive compared to any previous modality, because we do not have to create a new channel through the injury. (Figure 1) Before the soft fiberoptic ureteroscope there was the hard mirror, which could only go straight ahead, to the end of the ureter, and then it couldn’t turn further down into the kidney, it was just this one step away. With a soft mirror, it can slide down into the kidney during the bending process and get rid of the stones. (Figure 2) This fiberoptic ureteroscope is so soft that it looks like a plastic tube, and this plastic tube has many fine tools integrated inside. Nowadays, the thinnest fiberoptic ureteroscope can be 2 mm in diameter, and two optical channels are integrated in a 2 mm space to illuminate the surgery; of course, the surgical instrument channel is also integrated, and many lithotripsy tools have to enter through the instrument channel; there is also a part responsible for the control, which is a wire to control the movement of the head end, and a lot of contents are integrated in this 2-3 mm space. (Figure 3) Because of the bendable nature of the ureteroscope, theoretically every structure of the kidney will be accessible to it. However, in practice, the fiberoptic ureteroscope still has its blind spot, and some specific locations cannot be fully reached. Of course, any lithotripsy method, including open surgery, has a blind spot in the kidney. The structure inside the kidney is not simply square or round as imagined, the stone is there for us to get. There are many, many calyces inside the kidney. The so-called calyces are the containers that hold the urine filtered out by the effective structures of each group of kidneys, and finally all the calyces then converge into a large cavity called the renal pelvis. Due to the complexity of the kidney structure, it is not always possible to reach all the spaces in each surgical procedure, and there is a possibility that stones may remain in the end.