Urolithiasis is one of the most common urological diseases, affecting at least 1–20% of the population [Trinchieri A., Health Publications: Paris, 2003], most often among people of working age (20–60 years). If we analyze patients hospitalized in urology departments, 30–40% of them are diagnosed with urolithiasis. Considering its growth rate (more than 37% over the past 20 years [Gambaro G., J Urol, 2017]), prevalence, and chronic nature (sometimes lasting a lifetime) – leading to loss of work ability on one hand and to sepsis, acute or chronic renal failure, and even death on the other – the condition is not only a medical issue but also a social one.
When to See a Urologist for Stone Removal:
Today, the introduction of new diagnostic and treatment methods, as well as modern organizational and methodological approaches, has significantly improved the quality of life of patients with urolithiasis. Over recent decades, the proportion of open surgeries for this condition has decreased to nearly zero [Basiri A., Urol J, 2014]. This became possible thanks to the widespread use of advanced medical technologies – primarily extracorporeal shock-wave lithotripsy (ESWL) – and endoscopic treatment methods such as ureteroscopy, pyeloscopy, and contact lithotripsy.
- Stone growth in the kidney exceeding 5 mm (since the last examination);
- High risk of stone formation;
- Obstruction caused by stones;
- Infection caused by stones;
- Symptomatic stones (pain, hematuria);
- Kidney stones larger than 5 mm (the risk of clinical manifestation or the need to treat asymptomatic calyceal stones is about 10–25% per year [Inci K., et al. J. Urol, 2007]);
- Patient’s preference;
- Social factors (profession or frequent travel);
- Planned pregnancy.
How Kidney and Ureter Stones Are Crushed with Ultrasound
Extracorporeal shock-wave lithotripsy (ESWL, DLT) is one of the fundamental treatment methods for urolithiasis and a recommended approach for removing small and medium-sized stones (<20 mm) in most international guidelines.
Indications for the Procedure
Indications for this procedure [Guidelines on Urolithiasis; EAU Guidelines, 2020 – first 3 points]:
- Kidney stones up to 20 mm in size, except for those in the lower calyx.
- Lower calyx kidney stones up to 10 mm.
- Stones in the upper and lower ureter less than 10 mm.
- Bladder stones.
Principle of Device Operation
The principle of extracorporeal lithotripter operation is based on breaking stones in the urinary tract with focused acoustic shock waves generated in water by a submerged spark discharge or another energy source. The stone is gradually destroyed and fragmented into fine sand-like particles that are naturally excreted with urine. The shock wave passing through the body outside the focal zone – where the stone is located – does not damage surrounding tissues or organs. No incisions, punctures, or insertion of endoscopic instruments into the urinary tract are required, making this treatment method minimally invasive and highly effective.
Procedure Steps
The patient is positioned on the operating table. A soft, water-filled cushion is placed against the body by the doctor. Under ultrasound guidance, the shock wave passes through the body and is precisely focused on the stone.
Kidney stone fragmentation, patient positioning.
Ultrasound visualization of a kidney stone in the same patient.
Fragmentation of an upper ureter stone, patient positioning.
Ultrasound visualization of an upper ureter stone in the same patient.
Fragmentation of a mid-ureter stone, patient positioning.
Ultrasound visualization of a mid-ureter stone in the same patient.
Fragmentation of a lower ureter stone, patient positioning.
Ultrasound visualization of a lower ureter stone in the same patient.
It should be noted that this method is used for both adults and children. The procedure lasts 40–60 minutes. The ultrasound stone fragmentation procedure is so minimally invasive that it can be performed on an outpatient basis. After the procedure, the urologist monitors the patient for about 1 hour, and if there is no pain, the patient is discharged home. During the postoperative period, patients are advised to drink plenty of fluids, filter their urine to collect stone fragments for analysis, and take pain relief medication if needed.
Contraindications for Shock-Wave Lithotripsy:
- Pregnancy;
- Blood coagulation disorders (hemophilia, anticoagulant use, menstrual period in women);
- Active stage of urinary tract infection;
- Musculoskeletal deformities or severe obesity preventing proper patient positioning and accurate shock-wave targeting of the stone;
- Aortic aneurysm or any artery located within the area of shock-wave exposure;
- Urinary tract obstruction below the stone’s location.
Ureteroscopy and Laser Fragmentation of Ureteral Stones
Ureteroscopy is a procedure in which a thin instrument (ureteroscope) is inserted into the bladder and then into the ureter (the “tube” connecting the kidney to the bladder) and used for diagnosing and treating various urinary tract conditions. In cases of ureteral stones, ureteroscopy allows the urologist to visualize the ureter, locate the stone, and remove it. The ureteroscope can be rigid or flexible, allowing the doctor to advance up the ureter to the stone and view it on a video monitor via fiber optics.
Reducing the outer diameter of ureteroscopes and introducing modern semirigid miniscopes and flexible (fibroureteroscopes) instruments have, in most cases, eliminated the need for dilation of the ureteral orifice and lower ureter, significantly reducing the frequency of cases where upper urinary tract lesions were inaccessible and minimizing ureteral trauma.
Ureteroscopic lithotripsy has become the method of choice for treating ureteral stones due to its safety and effectiveness [Lane, J., et al., Curr Urol Rep, 2020]. Endoscopic stone removal involves visualizing the stone within the urinary tract while applying energy to fragment it into small pieces or dust. The holmium laser remains one of the most widely used tools in urological procedures, including stone fragmentation. One of its main advantages is its ability to effectively fragment stones regardless of their size, hardness, chemical composition, or consistency, ensuring a high rate of complete stone clearance. Therefore, laser ureteroscopic lithotripsy is recommended as the gold standard of intracorporeal lithotripsy for endoscopic treatment of urinary stones [Aboumarzouk, O.M., et al. J Endourol, 2012].
Technique of Ureteroscopy and Contact Lithotripsy
Contact lithotripsy is performed under anesthesia. The anesthesia type is chosen by the anesthesiologist depending on the patient’s age and condition. Endotracheal, intravenous, or epidural anesthesia may be used.
The sequence of ureteroscopy and contact lithotripsy includes several stages:
1. Entry into the bladder and visualization of the ureteral orifice. Mahesh R., B J U, 2011.
2. Passage through the orifice and intramural portion of the ureter. Mahesh R., B J U, 2011.
3. Visualization of the calculus, assessment of its size and shape, evaluation of nearby mucosa, and selection of the removal method.
4. Performing the contact laser procedure.
5. Removal of stone fragments using forceps or a retrieval loop.
6. Ureteral stenting – performed after removal of large stones, in cases of significant ureteral mucosal edema, or in the presence of urinary tract infection. A stent is a plastic tube approximately 1.6–2.0 mm in diameter, with two curled ends shaped like a “pig’s tail,” hence the name JJ-stent. The stent connects the kidney and the bladder, relieving ureteral obstruction, reducing mucosal swelling, and allowing small stone fragments to pass after lithotripsy. Most patients tolerate the stent well, although some may experience mild discomfort or frequent urination. Fortunately, the stent is temporary – usually kept for several days. Removal is painless and takes only 30–40 seconds.
Advantages of Contact Lithotripsy Over Extracorporeal Lithotripsy:
- The ability to remove the stone in a single session, ensuring rapid relief of upper urinary tract obstruction.
- Removal of ureteral stones located beyond the reach of ultrasound or X-ray imaging.
- Removal of stones associated with anatomical abnormalities or distal obstruction of the upper urinary tract.
- The possibility of performing contact lithotripsy in pregnant patients.
Data from Guidelines on Urolithiasis; EAU Guidelines, 2020:
The overall stone-free rates for ureteroscopic and extracorporeal methods are comparable. However, for larger stones, complete fragment clearance is achieved earlier with laser treatment. At the same time, ureteroscopic laser lithotripsy is associated with a higher risk of complications. Compared to ESWL, the laser method for ureteral stones demonstrates a higher rate of complete stone removal at 4 weeks, although this difference is not statistically significant after 3 months of follow-up. After laser lithotripsy, the rate of retreatment is lower, but the frequency of additional interventions, complications, and hospitalization duration is higher. ESWL is characterized by low invasiveness.
Conclusions. ESWL is the least invasive method of stone removal and provides high treatment efficacy when performed according to proper indications. However, its effectiveness is limited for large stones, cystine stones, or calculi causing ureteral obstruction. Laser lithotripsy is more traumatic compared to ESWL but achieves a higher rate of complete stone clearance in the ureter and kidneys. The holmium laser remains the most effective and widely used laser available today.
