1, clinical data 1, 1 general information The group of 75 cases, 61 men, 14 women, age 17-66 years old, 39 cases on the left side, 35 cases on the right side, 1 case of bilateral, 11 cases in the upper segment, 40 cases in the middle segment, 24 cases in the lower segment. Stone size 0,4-0,7cmX1,2-2,2cm, 3 cases of multiple occurrence, 12 cases of combined stone segment polyps and inflammatory tissue encapsulation, 4 cases of stenosis, 10 cases of ineffective ESWL, 3 cases of stone street formation.Ultrasound showed that the affected side of the mild effusion of 45 cases, moderate or more than 23 cases of effusion, IVP does not show up in 5 cases, 1 case of bilateral stone combined with postrenal renal failure. 1,2 Treatment method Continuous epidural anesthesia, lithotomy position. The bladder was entered under the surveillance of imaging system using Japanese Olympus F7 or F8/9,8 ureteroscope and Holmium laser (power 60w) of American Kojima Company. After finding the ureteral orifice on the affected side, a zebra guide wire is inserted, and the ureteral orifice is entered along the guide wire with the “reverse picking method” under the condition of water injection by a hydraulic pump, and then the irrigation pressure is lowered, and the scope continues to enter to the stone. Holmium 550μm laser fiber is inserted through the working channel of ureteroscope, and the power is adjusted to 05-1,0J/5-10Hz, aiming at the stone, and the stone is broken down to less than 2mm by the method of “worm-eaten”, and part of the stone fragments can be discharged with the rinsing liquid. Some of the stone fragments can be discharged with the rinsing fluid. Combined with polyps or inflammatory tissues, they can be removed together, and if there is a stenosis at the stone, holmium laser can be used to incise it first. If the mucosa bleeds during the operation, the fiber optic tip is about 0.5mm away from the bleeding area, and the bleeding is stopped with the energy emitted in the mode of electrocoagulation. A double-lumen urinary catheter was left in place postoperatively and removed after 1-2 days. F5 double-j tube was routinely placed and removed cystoscopically after 2-4 weeks. The average length of hospital stay was 35.2 min. 2 cases were hospitalized for 2-5 days after the operation, and the average length of hospital stay was 2.4 days. 2 cases of small stones in the upper part of the kidney were washed into the renal pelvis, but they were not found, and ESWL was carried out after the operation. 2 cases were combined with stenosis, which was perforated during holmium laser incision, and the operation was changed to an open operation. 12 cases of stones combined with polyps and inflammation tissues were resected with holmium laser, and the lumen of the tubes was clear. 7 cases were combined with bleeding of the mucous membrane in the ureter around the stone, and holmium laser electrocoagulation was used, and the bleeding was stopped satisfactorily. Holmium laser electrocoagulation was used in 7 cases with bleeding in the ureteral mucosa around the stone. There was no serious complication such as ureteral avulsion during the operation. There was no postoperative fever, infection, etc. In 71 cases of holmium laser lithotripsy, the stone removal rate was 94.3% (67/71) after 2-6 weeks of follow-up, and the hydronephrosis of the affected kidneys was reduced to different degrees on ultrasound. In one case of combined long segment stenosis, the stone was not discharged in 1 month after surgery and the amount of hydronephrosis increased compared with the preoperative period, so the patient was re-admitted to the hospital for open surgery to remove the stone and the stenosis segment was resected. 3, Discussion Holmium laser is a high-energy pulsed solid laser with a wavelength of 2100nm, an output energy of 0,2-4,0J, and an output frequency of 5-45Hz, and a conductive optical fiber that is not only fine but also bendable, which is recognized as the best energy source for intracavitary lithotripsy. Its lithotripsy effect mainly depends on the photothermal effect and the secondary shock wave effect to play, can break various types of stones, the number of 2mm fragments of broken stones are increased proportionally with the pulse energy. Compared with the high pulse energy, the low pulse energy is slower, but relatively safe, with less damage to the fiber, more complete stone crushing, and less obvious displacement of stones during lithotripsy. Therefore, the holmium laser lithotripsy effect is optimal at higher frequencies and lower pulse energies (less than 1.0 J). We have the same experience in the actual treatment, and the best results are obtained with high frequency and low energy settings, which result in the stones being powdered and discharged quickly after the operation, with a high discharge rate. [3](3) If there is a stenosis underneath the stone, or if there is a hyperplastic polyp or granulation tissue wrapped around the stone, holmium laser ablation of the polyp or incision of the stenosis ring should be performed first, and holmium laser lithotripsy should be performed after the guidewire is passed through the stenosis. In two cases of combined stenosis, the guidewire could not be passed, and after holmium laser perforation, open surgery was performed, and the ureter was found to be nearly atretic in the stenotic segment below the stone, with a length of nearly 1 cm. In one case of combined stenosis, the stone had not been discharged and the amount of fluid had increased, so the patient was readmitted to the hospital for incision and removal of the stone, and the stenotic segment was resected. We believe that if the stenosis is long and the guidewire is not easy to pass, and if the lumen cannot be patented by holmium laser incision, then open lithotripsy and resection of the stenosis should be performed. In conclusion, ureteroscopic holmium laser lithotripsy is highly efficient, minimally invasive, safe, and has a fast recovery in the treatment of urinary stones, and is the treatment of choice for ureteral stones. [4] It can be used to treat concomitant polyps, stenosis and other lesions at the same time, and it is also an ideal choice for ureteral stones that fail ESWL.