Minimally invasive treatment of upper urinary tract stones has progressed and even revolutionized in the last 20 years, with about 90% of stone cases being treated minimally invasively and with few complications. A variety of treatment options are now available. They include extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy for stone extraction and lithotripsy (PCNL), pneumatic ballistic lithotripsy (PL) and laser lithotripsy (LL) under ureterorenoscopy (URS), flexible ureterorenoscopic lithotripsy, retroperitoneoscopic surgery, combined minimally invasive, open combined minimally invasive treatment, etc. The size of the stone, the presence of site, combined polyps, inflammation, obstruction, etc., due to anatomical factors of the kidney and ureter, etc., make it possible to selectively utilize these treatments. We started the clinical application of some minimally invasive methods in 2002. In this paper, we analyze the minimally invasive treatment methods for upper urinary tract stone calculi in recent years and review them in light of the literature. The incidence of urinary tract stones is widespread, with a high recurrence rate and complex causes. The incidence is extremely high in the southern provinces of China, Hong Kong and Macao, and there is no fundamental treatment and prevention method for urinary stones. Some studies have shown that 10% of asymptomatic kidney stone patients will develop symptoms or require treatment each year; with a five-year follow-up, about half of the patients will progress, and for stones over 1 cm in diameter, the probability of such progression will be even greater, reaching 47% within two years. The growth and change of stones can clinically cause infection, obstruction, renal hypoplasia and other hazards, and active treatment is especially important. 2. Commonly used minimally invasive treatment methods For ureteral stones, minimally invasive treatment is gradually replacing traditional open surgery, and progress in minimally invasive treatment of kidney stones is also gradually achieved. Commonly used methods include: ESWL, PCNL, ureteral rigidoscopic pneumatic ballistic lithotripsy, laser lithotripsy, flexible ureteroscopic lithotripsy, posterior laparoscopic surgery and the combined application of endoluminal mirror, etc. 2.1. ESWL Extracorporeal shock wave lithotripsy (ESWL) has the advantages of easy operation, low pain and low cost. It has become the first-line method for the treatment of urinary stones. The treatment effect is affected by the size, location and composition of stones, as well as whether they are combined with infections and polyps. The literature reports that the combined clearance rate of ESWL for ureteral union is 57%-90%, and about 5%-60% of patients need repeat treatment or adjuvant treatment measures, and the size of ureteral stones is directly proportional to the effect of ESWL. The rate of discharge after re-fighting was significantly higher than the rate of discharge after initial treatment. ESWL treatment of ≥1 cm union was less effective, and the union load was one of the important factors affecting the larger stones and the shock wave energy index was not enough to achieve the crushing of stones. In addition, the lack of sufficient diffusion space after the shock wave fragmentation of larger stones is not conducive to further stone fragmentation, and the obstruction of stone discharge or even the formation of “stone street” is also a common reason for ESWL failure. Ding Chongbiao et al. reported 5140 patients with urolithiasis treated with ESWL, most of them had stones less than 2.0 cm in diameter, and concluded that routine examination before treatment should not be neglected, and the efficacy of low energy and emergency ESWL is satisfactory. Over the years, China has accumulated rich experience in ESWL for urinary stones, with a low complication rate and a 3.4% incidence of renal colic. However, the indications for extracorporeal shock wave lithotripsy are still limited and may cause different degrees of damage to the renal parenchyma in the long term. For complex stones, a double J-tube is placed before ESWL to prevent the formation of “stone streets”, and antler stones are not suitable for ESWL treatment, but only as an adjunctive treatment. Calcium oxalate monohydrate and cystine stones are more difficult to break up. The number of treatments should not exceed 3-5 times, and the interval should be 10-14 days. Contraindications are systemic bleeding disorders, people with pacemakers, morbid obesity, pregnant women, and systemic diseases that cannot tolerate the treatment. 2.2. Ureteroscopic pneumatic ballast lithotripsy and laser lithotripsy In 1977, GOODMAN reported the use of pediatric cystoscopy as a ureteroscope to observe the ureter in adults, and in 1980, PEREZ-GAS-TRO successfully manufactured the first rigid ureteroscope with a diameter of F11 and used it for ureteral examination and stone extraction. Between 1983 and 1985, the first ureteroscopes were introduced to China in Beijing and Guangzhou, but at that time, the ureteroscopes were thicker (F13-F16), the efficiency of the intracavitary lithotripsy equipment was lower, and the complications were higher. Since the 1990s, ureteroscopy has been continuously improved due to the rapid development of medical engineering, electronics, and material technology. The introduction of fiberoptic guide beams, both rigid and flexible, has greatly reduced the caliber of the ureteroscope. The introduction of increasingly sophisticated operating instruments has also reduced the diameter of the working channel. At the same time, ureteral dilatation techniques have evolved from blind dilatation with a dilator tube, to dilatation with a guidewire-guided dilator and balloon, to simple hydraulic dilatation today. Ureteroscopic lithotripsy tools have also become more sophisticated, from ultrasonic and electrohydraulic lithotriptors to pneumatic ballistic lithotriptors and laser lithotriptors. Many of the techniques used to get the ureteroscope into the tortuous lumen are based on vascular interventions. The continuous improvement of these devices and techniques has greatly facilitated the clinical use of ureteroscopic lithotripsy, and the incidence of complications such as ureteral injury has been greatly reduced. Currently, URL has irreplaceable advantages in the treatment of middle and lower ureteral stones, such as high stone retrieval rate, short duration of symptoms, and simultaneous removal of polyps in the stone area. The development of highly efficient intraluminal lithotripters, especially the Holmium laser, has made ureteroscopy more useful in the treatment of distorted ureteral stones and stones in the lower renal calyces, and the success rate of treatment and stone removal has reached more than 90%, and the incidence of serious complications such as ureteral mucosal exfoliation, ureteral perforation and rupture is < 3% [10211 ]. Nowadays, ureteroscopy has established an irreplaceable position in the management of ureteral stones, especially in the treatment of distal ureteral stones. The choice between ESWL and URL as first-line treatment is based on the hospital's equipment and the physician's skill and experience. For upper ureteral stones, ESWL is generally preferred if the history is less than 1 month, while URL or MPCNL is preferred if the history is long, the stone is large and is complicated by moderate to severe hydronephrosis in the ipsilateral kidney, when polyps are often formed around the stone. At present, the direct approach method and the guidewire-guided approach+1 are mainly used to enter the ureteral opening along the catheter under direct vision with hydraulic pump irrigation, and repeatedly adjust the speed of the mirror and flushing fluid to visualize the stone under direct vision. Ureteroscopic pneumatic ballistic lithotripsy and laser lithotripsy are then performed. We have been using ureteroscopy in clinical practice since 2002 and have gained extensive experience. Pneumatic ballistic lithotripsy is a new type of lithotripsy system invented in 1990s, which uses the energy generated by compressed gas to push the bullet body inside the handle, and the bullet body pulses to impact the stone and break the stone. It has the advantages of reliable lithotripsy effect, safe and efficient, slight damage and low treatment cost. At present, it is widely used in the treatment of ureteral stones, but the key to successful lithotripsy is to prevent the upward movement of stones. The application of pneumatic ballistic combined with ultrasonic lithotripsy system has improved the stone removal rate in phase I and reduced the stone residual rate more effectively. Laser lithotripsy commonly includes holmium laser lithotripsy, and now new laser methods are constantly appearing, such as: dual-frequency double-pulse laser lithotripsy. Holmium laser performance characteristics: ① Holmium laser is a high-energy pulsed solid laser with high lithotripsy efficiency. Holmium laser can treat polyps and ureteral strictures at the same time, eliminating factors unfavorable to the combination of discharge and increasing the stone removal rate. Comparison between the two: The cost of laser lithotripsy is higher than that of pneumatic ballistic lithotripsy. It is significantly better than the former for ureteral stones with combined polyps and strictures. Due to the continuous updating of the ureteroscope, the caliber is shrinking, which makes it easier to enter the ureter with direct vision, high quality mirror image and easy operation. With the application of ureteroscopy (URL) technology, the pneumatic ballast and holmium laser techniques have been promoted. For 2cm, PCNL is the best treatment method. For residual stones or obstructed stones after MPCNL treatment, ESWL is an effective treatment. For various reasons, ESWL, URL and MPCNL are not feasible or have failed, and are absolute indications for posterior laparoscopic pelvic or ureteral lithotripsy; also, large or hard ureteral stones, prolonged impaction or complete obstruction of solitary kidney stones with significant surrounding fibrous or granulomatous growth are indications for the procedure. Comprehensive treatment is feasible in stage I or II. For complex, multiple and recurrent stones, depending on the conditions, posterior laparoscopy and combined stone extraction can be chosen, taking into account various factors such as the brittle composition of the stone, whether it is combined with complications and anatomical features of the renal ureter. ESWL and URL are now widely used and the technology is constantly being improved. The residual rate after minimally invasive treatment of ureteral stones is very low. For complex kidney stones, it is unavoidable to have a small amount of stone fragments remaining in the kidney when treated with modern urological techniques. There is a fundamental difference between residual stone fragments and residual stones, which should be carefully selected and applied according to different cases in the selection of treatment modalities and intraoperative procedures to reduce the presence of residual stones and fragments. Approximately 75% of residual stone fragments are clinically asymptomatic and are followed up and reviewed closely after surgery to prevent recurrence and urinary tract infection. For horseshoe kidney and transplanted kidney with concurrent stones, ESWL or PCNL can be used for treatment. Li Xun et al. treated 13 cases of transplanted kidney stones with intracavitary technique and concluded that percutaneous renal puncture for stone extraction and paracentesis are the key to successful treatment.