In 1980, extracorporeal shock wave lithotripsy (ESWL) was first used in clinical practice, and the Department of Urology of Shanghai Jiuxin Hospital was the first to perform extracorporeal shock wave lithotripsy in China, and has completed the treatment of more than 17,000 cases of urinary tract stones. With the accumulation of clinical experience and the continuous updating of lithotripter equipment, the indications for ESWL treatment of urinary tract stones have been expanded over the past 20 years of application of extracorporeal shock wave lithotripsy, and it has so far become one of the standard methods of choice for the treatment of upper urinary tract stones.
Patient selection
I. Systemic conditions
1. Pregnancy: Since the application of lithotripter in clinical practice, pregnancy has been an absolute contraindication to ESWL, no matter in early or late stages of pregnancy, because ESWL may lead to fetal abortion and malformation, so patients with such stones are advised to switch to other treatment methods or wait until after delivery for ESWL treatment. Female patients with lower ureteral stones in the reproductive age should also not use ESWL, because the shock wave focus is too close to the uterus and ovaries, and the shock wave may have different degrees of impact on their functions.
2. Abnormal coagulation mechanism: The most common histobiological effect of shock wave is bleeding, therefore, if the patient has bleeding disorders, it may lead to hemorrhage or bleeding from the target organ.
3.Severe cardiovascular disease: Shock wave is not suitable for patients with cardiopulmonary insufficiency and severe arrhythmias because of the risk of aggravating the disease.
4. Active tuberculosis: The tissue damage caused by shock wave will promote the spread of Mycobacterium tuberculosis to the blood, so ESWL is not recommended for those with active tuberculosis of the urinary system.
Urinary system condition
1.Urinary obstruction in the distal part of the stone: if the stone is obstructed by various reasons such as congenital malformation, polyp or tumor, it is difficult to discharge the stone after it is broken, and the accumulation of fragments will aggravate the obstruction, so ESWL is not suitable for these patients for the time being.
2. Renal insufficiency: A large number of clinical studies have shown that ESWL can cause transient renal hypoplasia, but there is no definite conclusion whether there are long-term effects. If the renal insufficiency is caused by stone obstruction, the stone should be actively broken to release the obstruction; if it is not caused by stone obstruction, the stone should not be broken to avoid aggravating the renal function.
3. Urinary tract infection: ESWL is forbidden during the acute urinary tract infection period because it is prone to inflammatory spread leading to sepsis. Chronic inflammation is usually difficult to eliminate in the short term, so lithotripsy can be performed after 3-4 days of effective antimicrobial treatment. After lithotripsy, observation should be strengthened and antimicrobial agents should be continued for a period of time.
3. Stone condition
The location, size, composition, structure, morphology, length of time in the urinary tract and the presence of fluid can affect the lithotripsy effect.
Pre-treatment preparation
1. Psychological aspects: Patiently explain the general principles and procedures of ESWL to patients, especially those who have doubts and fears, and seek the patient’s cooperation.
2. Systemic aspects: Take a detailed history of the patient’s heart, lungs, liver, kidney and blood system, take blood pressure, check blood routine, clotting time, liver and kidney function, electrocardiogram, etc. If aspirin and non-steroidal anti-inflammatory drugs are used, they should be stopped for at least 2 weeks before treatment, and check coagulation function; take a laxative at 8:00 pm one day before treatment, eat easy-to-digest food in the morning of the treatment day, and avoid flatulence-prone food. If lithotripsy is performed in the afternoon, eat easily digestible food at noon of the same day.
3. Urinary system: Ultrasound, KUB+IVP, CTU or retrograde pyelogram of the urinary system should be performed before treatment to have an overall understanding of the patient’s urinary system anatomy, function and stone condition; routine urine examination, urine bacterial culture + drug sensitivity if necessary. On the day of lithotripsy, KUB or preoperative electrodialysis localization was performed to understand the exact location of the stone.
Post-treatment treatment
I. General treatment
1. Drink more water: ensure the daily urine volume is above 2000ml. If there is difficulty in drinking water, intravenous rehydration should be given.
2, moderate exercise: appropriate increase in physical activity can help stone removal, but too much exercise has the risk of causing obstruction due to large number of stone fragments, so patients with huge kidney stones or isolated kidney stones should not be strenuous activity immediately after stone fragmentation.
3. Postural drainage: If the stone in the lower renal calyx is difficult to be discharged due to anatomical factors, the patient can be placed in a head-low, foot-high position and percussion on the lower back to facilitate the discharge of stone fragments.
II. Auxiliary measures
Hemostasis: almost every patient will have hematuria after ESWL, but most of them are mild and disappear within 1-2 days; a few patients with more severe symptoms or longer duration can be given certain hemostatic agents.
2.Medication for stone removal: Chinese medicine such as stone removal punch can be taken.
3.Antispasmodic: stone fragments may cause pain or even colic in the process of downward movement; those with heavy symptoms may be given intramuscular antispasmodic agents.
4.Antibiotics: antibiotics are not used routinely, but can be used if there was urinary tract infection before lithotripsy.
3. Stone review
X-ray or ultrasound (negative stones) will be reviewed 2 weeks after lithotripsy to understand the situation of stone crushing and discharge. If the stone has disappeared, the treatment ends here; if the stone fragment is ≤3mm, continue the conservative treatment and review after 1-3 months; if the fragment is >3mm, the decision will be made according to the specific situation.
Complications and their prevention
1. Ureteral debris accumulation: If the “stone street” does not disappear on its own within 1-2 days, ESWL should be performed again; if it is accompanied by fever or colic, ESWL should be performed urgently; if ESWL treatment fails, endoluminal technique can be used to remove the stone.
2. Fever: Fever mostly appears within 1-3 days after lithotripsy and is often accompanied by lumbar pain on the affected side, which can be treated with antibiotics. If ureteral stone accumulation is found at the same time, active measures should be taken to release the obstruction.
Hemorrhagic complications: hematuria, renal parenchymal and perirenal bleeding, skin bleeding, gastrointestinal bleeding and coughing up blood and sputum, which are usually relieved by symptomatic treatment.
Cardiac complications: They are rare but most serious, so patients with a history of cardiac disease should be monitored intraoperatively, and cardiac arrhythmias should be stopped immediately once they occur.
Changes in renal function: In general, ESWL does not cause serious damage to patients with normal function of both kidneys, but special care should be taken for patients with isolated kidneys or a previous history of renal disease.