Urolithiasis is one of the common diseases in urology, and occupies the first place among urology inpatients. The incidence of urinary stones in China is 1% to 5%, and as high as 5% to 10% in the south; the annual new incidence is about 150-200/100,000 people, 25% of whom require hospitalization. In recent years, the incidence of urinary stones in China has increased, and it is one of the 3 major areas with high incidence of stones in the world. In recent years, with the in-depth research on the etiology of urinary stones, the metabolic risk factors of stones have become more and more important to urologists. Extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotripsy (PNL), ureterorenoscope lithotripsy (URL), and laparoscopic lithotripsy have been performed. URL), and laparoscopic lithotripsy (1aparoscope lithotomy) have emerged one after another, making the treatment of urinary stones gradually develop in the direction of minimally invasive. I. Risk factors for stone formation There are many factors that affect stone formation. Age, gender, race, genetics, environmental factors, diet and occupation have a great influence on stone formation. Metabolic abnormalities in the body, obstruction of the urinary tract, infection, foreign body and drug use are common causes of stone formation. Focusing on these issues can reduce the formation and recurrence of stones. 1. Metabolic abnormalities (1) Urine acidity and alkalinity. (2) Hypercalcemia: Common diseases causing hypercalcemia include hyperparathyroidism, lacto-a-alkaline syndrome, nodular disease or sarcoidosis, vitamin D toxicity, malignancy, cortisolism, hyperparathyroidism, pheochromocytoma, adrenal insufficiency, taking thiazide diuretics, recovery from acute tubular necrosis, multiple myeloma, hypothyroidism, and vitamin A toxicity. (3) Hypercalciuria: There are 3 types of primary hypercalciuria: absorptive hypercalciuria, renal hypercalciuria and reabsorptive hypercalciuria. In addition, some metabolic diseases of clear etiology can also cause secondary hypercalciuria and the formation of calcium-containing stones in the urinary tract, such as distal tubular acidosis, nodular disease, long-term bed rest, bone Page-t disease, glucocorticoid excess, hyperparathyroidism and vitamin D toxicity. Among them, about 0.5%-3% of patients with urinary calcium stones have distal tubular acidosis. (4) Hyperoxaluria Primary hyperoxaluria [type I is glycolicaciduria and type II is glycericaciduria] is rare. Causes of secondary hyperoxaluria include excessive intake of VitC, excessive intake of oxalic acid and its precursors in the diet, decreased intake of calcium in the diet, enterogenic hyperoxaluria, and VitB6 deficiency. A common cause of increased urinary oxalate is increased absorption of enteric-derived oxalic acid and its precursors. On the other hand, hyperoxaluria associated with disturbances in bile acid metabolism and excessive water loss can also occur after small bowel resection or short-circuit surgery, steatorrhea, or in Crohn’s disease. In addition, it has been suggested that the number of oxalobacteria (O. formigenes) in the intestine is reduced in patients with hyperoxaluria. (5) Hyperoxaluria. (6) Cystinuria. (7) Hypocitraturia. (8) Hypomagnesuria. 2. Local etiology Urinary tract obstruction, infection and the presence of foreign bodies in the urinary tract are the main local factors that induce stone formation. Obstruction can lead to infection and stone formation, while stones themselves are foreign bodies in the urinary tract, the latter of which can aggravate obstruction and infection. Clinical obstructive diseases that predispose to urinary tract stone formation include two major categories: mechanical and dynamic obstruction. Among them, pelvic ureteral junction stenosis, bladder neck stenosis, spongy kidney, renal ureteral malformation, ureteral orifice bulge, renal cyst, renal calyx diverticulum and horseshoe kidney are the common mechanical obstructive diseases. In addition, intrarenal-type pelvic and calyx neck stenosis can cause urinary retention, which can induce the formation of kidney stones. Neurogenic bladder and congenital giant ureter are power obstructive diseases, the latter two can also cause retention of urine and promote stone formation. 3, drug-related factors Drug-induced kidney stones account for 1% to 2% of all stones, divided into 2 major categories: a class of high concentration of urine and relatively low solubility of drugs, including aminopterin (triamterene), the treatment of HIV infection drugs (such as indinavir indinaVir), magnesium silicate and sulfonamides, these drugs are themselves components of the stone. Another group of drugs that can induce stone formation include acetazolamide, VitD, VitC and corticosteroids, which are metabolized in the process of leading to the formation of stones of other components. Diagnosis 1. Imaging examination Imaging examination should be done in all patients with clinical symptoms of urinary stones, and the results are of great value for further examination and treatment of stones. (1) Ultrasound (recommended): Ultrasound examination is easy, economical, non-invasive, and can detect X ray positive and negative stones above 2mm. In addition, ultrasound examination can understand the degree of dilatation of the urinary tract above the stone and indirectly understand the renal parenchyma and collecting system. For bladder stones, ultrasonography is able to observe both the bladder and prostate and look for causative factors and complications of stone formation. However, ultrasonography is less sensitive in diagnosing stones in the middle and lower ureter due to the influence of intestinal contents. Ultrasound can be used as a routine test for urinary stones, especially as the method of choice in cases of renal colic. (2) Urethral plain film (KUB plain film) (recommended): Urethral plain film can detect about 90% of X-ray positive stones, and can roughly determine the location, morphology, size and number of stones, and initially suggest the chemical nature of stones. Therefore, it can be used as a routine method of stone examination. On urethral plain films, stones of different composition are visualized in the following order: calcium oxalate, calcium and magnesium ammonium phosphate, cystine, and urate-containing stones. Simple uric acid stones and xanthine stones are able to pass through X-rays (X-ray negative), and cystine stones have a low density, the latter being more faintly visualized on urethrograms. (3) Intravenous urography (IVU) (recommended): IVU should be performed on the basis of urograms. Its value is to understand the anatomy of the urinary tract, to determine the location of stones in the urinary tract, to detect X-ray negative stones that cannot be shown on urograms, and to identify suspicious calcified foci on plain films. In addition, the function of the divided kidney can be understood and the degree of hydronephrosis can be determined. In cases where the function of one side of the kidney is severely impaired or where the kidney is not visualized with a normal dose of contrast, the use of an increased contrast dose (double or high dose) or a delayed film can often achieve renal visualization. During an attack of renal colic, the diagnosis of stones can be difficult because acute urinary tract obstruction often leads to non-development or poor visualization of the urinary tract. (4) CT scan (optional): CT examination is usually not required for the diagnosis of urinary stones. However, because CT scan is not affected by stone composition, renal function and respiratory motion, and because spiral CT is also capable of simultaneous two- and three-dimensional reconstruction of the acquired images, it can detect small stones that are easily missed in other conventional imaging examinations. It is an important complement to X-ray. In addition, the composition and fragility of stones can be initially assessed by different CT value changes, which can provide a reference for the choice of treatment. Enhanced CT can show the degree of hydronephrosis and the thickness of the renal parenchyma, thus reflecting the altered renal function. (5) Retrograde or percutaneous nephrostomy (optional): It is an invasive test and is not used as a routine test. It is only used when intravenous urography is unrevealing or poorly visualized and when X-ray negative stones are suspected and further differential diagnosis is needed. (6) Magnetic resonance water imaging (MRU) (optional): magnetic resonance is extremely poor for the diagnosis of urinary tract stones, and therefore is not generally used for stone examination. However, magnetic resonance water imaging (MRU) is able to understand the situation of upper urinary tract obstruction, and the same effect as intravenous urography can be obtained without contrast, independent of changes in renal function. Therefore, it can be considered for patients who are not suitable for intravenous urography (e.g., contrast allergy, severe renal impairment, children, and pregnant women). (7) Radionuclide (optional) Radionuclide examination cannot directly show urinary stones, however, it can show the morphology of the urinary system and provide renal blood perfusion. The information on renal function and urinary tract obstruction is therefore valuable for the selection of surgical options and the evaluation of surgical efficacy. In addition, renal dynamic imaging can also be used to assess the impact of extracorporeal shock wave lithotripsy on renal function. Laboratory tests (1) Routine laboratory tests for patients with stones should include blood analysis, urinalysis and stone analysis. (2) Urinalysis for complex kidney stones: further urinalysis may be an option for patients with complex kidney stones (meaning patients with recurrent stones, with or without intrarenal residual stones and special risk factors). (3) Urine collection protocol. (4) Evaluation of test results: Measurement of serum/plasma calcium is useful in the diagnosis of hyperparathyroidism (HPT) or other disorders associated with hypercalcemia. If the blood calcium concentration is high (>2.60 mmol/L), parathyroid hormone levels should be measured to confirm the diagnosis or exclude HPT. Uric acid stones should be considered in the presence of x-ray negative stones with hyperuricemia, but may be demonstrated on CT films. Fasting morning urine pH>5.8 can be considered as complete or incomplete renal tubular acidosis, acid load test and blood pH, potassium, bicarbonate and chloride measurement should be done at the same time. Stone composition analysis is a method to confirm the nature of the stone, and is also an important basis for the development of stone prevention measures and the selection of lithotripsy therapy, in addition, it also helps to narrow the scope of stone metabolic assessment. Stone specimens can be obtained by surgery, lithotripsy and self-discharge. Stone composition analysis includes both qualitative and quantitative analyses, and usually qualitative analysis is sufficient to meet clinical needs. There are 2 methods of stone analysis: physical and chemical. The physical analysis method is more accurate than the chemical analysis method, and the commonly used physical analysis methods are infrared spectroscopy and other methods. The main drawback of the infrared spectroscopy method is that it can analyze both organic and inorganic components, as well as crystalline and non-crystalline components, and requires only 1 mg of specimens. However, the method is simple and inexpensive and can meet the clinical needs.