Definitions:
Extracorporeal shock wave lithotripsy (ESWL) is a shock wave generated by an extracorporeal lithotripsy machine, which is focused by the machine and aimed at the stones, and after multiple releases of energy, the stones in the body are broken up and eliminated with urine. In 1985, it began to be used clinically in China, and due to its advantages of small trauma, few complications, and no need for anesthesia, ESWL has become the conventional preferred method for urolithiasis.
Basic principle: The basic principle of shock wave generation (liquid electricity) is to form a high temperature and high pressure plasma region with high energy density on the discharge channel through high voltage, high current and instantaneous discharge, and quickly convert electrical energy into heat, light, force and sound energy, and the discharge channel expands sharply during the discharge process, forming a pressure pulse in the aqueous medium, that is, the shock wave. Generally speaking, all stone crushers are composed of two basic parts, namely the shock wave source that can crush the stone and the precise positioning system for the stone, and the shock wave source is the core of the stone crusher.
Positioning system: B-ultrasound positioning adopted by our hospital.
*Parameters: 2500 stages of kidney stones, ** interval of more than 2 weeks; Ureteral stones: 2500 stages, ** more than 1 week apart.
Preparation before gravel:
First of all, imaging examination of the urinary system should be carried out to determine whether there are stones, the location, size, number and hardness of the stones, as well as the condition of hydronephrosis and whether there is urinary tract obstruction below the stones, etc.; The commonly used imaging examination methods are: 1. B-ultrasound examination: The biggest advantage is that there is no X-ray radiation damage, which helps to judge the degree of renal hydrops, but the detection rate of small stones in the middle and lower ureters is low. 2. CT examination: judge the hardness of the stone according to its CT value, and then evaluate the difficulty of stone crushing. 3. Urogram: intravenous pyelogram (IVU): Routine application, urography helps to determine the exact location of the stone, and at the same time can understand the kidney function, whether there is obstruction below the stone, etc. Secondly, the patient's general condition should be evaluated before surgery, and routine blood routine, urine routine, blood coagulation, liver and kidney function, electrocardiogram and other examinations should be routinely performed.
Indications: 1. Kidney stones: <20mm; However, for columnar or antler-shaped stones with large diameters, the best plan should be selected according to the specific situation, and percutaneous nephrolithotomy or flexible ureteroscopy technique + percutaneous nephrolithotripsy is usually selected. If an attempt is made to perform extracorporeal shock wave lithotripsy on larger staghorn stones, a ureteral stent needs to be placed first to prevent excessive lithotripsy from forming stone knots and blocking the ureters;
2. Ureteral stones: <10mm; SWL is the first choice for stones located in the upper and lower ureters; >10mm；URS (ureteroscopic lithotripsy) is preferred for upper and lower ureteral stones;
3. Bladder stones: <25mm; **Secondary bladder stones, which are caused by obstructive diseases of the lower urinary tract, such as prostatic hyperplasia, urethral stricture, etc., should be the first choice for the first choice of bladder stones at the same time, rather than SWL alone.
Contraindications: 1. Systemic condition: 1. Combined with systemic hemorrhagic disease; 2. Severe skeletal deformity and severe obesity, affecting the location of stones and the conduction of energy (the straight-line distance from stones to ** should be less than 10cm); 3. There is an aneurysm around the stone; 4. Uncontrolled diabetes mellitus; 5.pregnant women; 6. Women should not be stone-crushed during menstruation; 7. Patients with pacemakers; 8. There is anatomical obstruction in the distal urinary tract of the stone.
2. Urinary system: 1. Renal function status, for patients with renal insufficiency caused by ureteral stone obstruction, extracorporeal shock wave lithotripsy may lead to further aggravation of renal function impairment; 2. For urinary tract infection, lithotripsy is not suitable during the acute inflammation of the urinary tract, and urogenic sepsis is very likely to be complicated by extracorporeal shock wave lithotripsy, so it is necessary to use effective antibiotics to control the infection before lithotripsy; 3. Extracorporeal shock wave lithotripsy is not recommended for patients with ureteral stones with a course of more than 2 weeks, according to the clinical summary, it is known that such patients mostly fail to pass stones due to the relatively narrow inner diameter of the ureter, if extracorporeal shock wave lithotripsy is performed at this time, the local edema of the relatively narrow ureter may be caused by lithotripsy after surgery, which will aggravate the stenosis and cause stone discharge failure; At the same time, it may be due to the long incarceration time of the stone, which may lead to the formation of local granulation tissue in the ureter, or even wrap the stone, and it is still difficult to discharge the stone fragments after lithotripsy; 4. Extracorporeal shock wave lithotripsy for patients with severe hydronephrosis may lead to aggravation of hydronephrosis after surgery, which in turn will lead to further aggravation of the already damaged kidney function.
3. The situation of the stones themselves: according to the chemical composition of the stones, the urinary tract stones are clinically divided into five categories: calcium oxalate stones, calcium phosphate stones, magnesium ammonium phosphate stones, uric acid stones, and cystine stones. In general, stones with a CT value of less than 900 Hu have a higher success rate of extracorporeal shock wave lithotripsy; If the CT value is 900-1000Hu, extracorporeal shock wave lithotripsy can be tried; If the CT value is greater than 1000 HU, the success rate of extracorporeal shock wave lithotripsy is extremely low.
Common postoperative complications:
1. Hematuria; 2. Renal colic; 3. Infection; 4. Visceral injury: such as kidney and intestinal injury; 5. Residual stones or stone streets; 6. Stenosis: It is more common in repeated lithotripsy in the same location.
Postoperative care and follow-up:
1. After gravel**, tell him to drink more water, move more, collect stones and send them for composition analysis; 2. If renal colic occurs during stone expulsion, you can use medicine to relieve pain and spasmodic, take traditional Chinese medicine for stone expulsion, infusion to control infection if necessary, and determine whether to restrict exercise and whether to use body position stone removal according to the situation; 3. Re-examination of urological ultrasound or CT 1-2 weeks after lithotripsy.
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