Modern Management of Urinary Stones Evolving Techniques and New Minimally Invasive Approaches
Urinary stone disease is one of the most common urological conditions in the general population. It is estimated that about 10–15% of people will develop at least one episode of urinary stones during their lifetime, with a higher prevalence in industrialized countries.
Urinary Stone Disease: An Increasing Condition
In recent years, an increase in the incidence of urinary stone disease has been observed. This trend is mainly attributed to changes in lifestyle and dietary habits. Diets rich in animal proteins and salt, low fluid intake, obesity, and metabolic syndrome represent important risk factors for stone formation.
How Stones Form
The formation of urinary stones is a complex process resulting from the interaction of metabolic, environmental, and genetic factors. Stones form when certain substances in the urine—such as calcium, oxalate, uric acid, or cystine—reach concentrations that favor crystallization and the subsequent aggregation into solid concretions. Stones may develop anywhere along the urinary tract: kidney, ureter, bladder, or urethra.
From a clinical standpoint, the most typical manifestation is renal colic, characterized by sudden and severe flank pain that may radiate to the groin or, in men, to the testicle. This pain is often associated with nausea, vomiting, and sometimes hematuria (blood in the urine).
From Traditional Surgery to Endourology
Over the past few decades, the management of urinary stones has undergone a profound transformation thanks to the introduction of increasingly sophisticated technologies and minimally invasive surgical techniques. Endourology, together with modern lithotripsy technologies, has progressively replaced traditional open surgical procedures, offering patients treatments that are more effective, safer, and associated with significantly shorter recovery times.
Until the second half of the twentieth century, treatment for urinary stones was mainly surgical. Open procedures such as pyelolithotomy or nephrolithotomy required large incisions, prolonged hospitalization, and often lengthy and painful postoperative recovery. The introduction of endourology has completely revolutionized the therapeutic approach. Endourology includes all techniques that allow access to the urinary tract through natural pathways or through small percutaneous accesses using miniature endoscopic instruments. Thanks to these advances, open surgery for urinary stones has become extremely rare and is now reserved only for highly selected cases.
Current Techniques for the Treatment of Urinary Stones
Currently, the main treatment techniques for urinary stones can be grouped into:
- Extracorporeal Shock Wave Lithotripsy (ESWL)
- Endoscopic lithotripsy by ureteroscopy
- Percutaneous nephrolithotomy (PCNL)
- Mini-PCNL and Micro-PCNL
Extracorporeal Shock Wave Lithotripsy (ESWL)
One of the most important innovations in the treatment of urinary stones was the introduction of Extracorporeal Shock Wave Lithotripsy (ESWL). Developed in the 1980s, this technique allows stones to be fragmented without any surgical incision. The principle is based on the generation of shock waves that are focused on the stone using radiologic or ultrasound guidance. These shock waves fragment the stone into small pieces that can later be eliminated naturally through the urine. ESWL remains an effective treatment particularly for small renal stones, renal pelvic stones, and proximal ureteral stones.
The main advantages are the absence of surgical incisions, outpatient procedure or short hospital stay, and minimal post-procedural pain. However, its effectiveness depends on the size, composition, and location of the stone.
Endoscopic Lithotripsy by Ureteroscopy
This procedure involves the insertion of a thin endoscopic instrument—the ureteroscope—through the urethra and bladder into the ureter. This technique allows direct visualization of the stone and fragmentation using different energy sources. Ureteroscopy is currently one of the most commonly used treatments for ureteral stones, with very high success rates.
The ureteroscope may be rigid or flexible (RIRS – Retrograde Intrarenal Surgery). Rigid ureteroscopes are mainly used for stones located in the distal and mid ureter, while flexible ureteroscopes allow access to the proximal ureter and the kidney, enabling treatment of stones located in the renal calyces. Modern digital ureteroscopes provide high-definition images that facilitate stone fragmentation.
One of the most important energies in endourology is the Holmium laser (Ho:YAG laser), which is highly effective regardless of chemical composition. More recently, the Thulium Fiber Laser has been introduced, offering higher energy efficiency, faster fragmentation, and reduced stone retropulsion (backward movement of the stone). After fragmentation, a small ureteral catheter—called a double-J stent—is usually placed and removed a few days later to facilitate the process.
Percutaneous Nephrolithotomy (PCNL)
When kidney stones are particularly large or complex, it may be necessary to perform Percutaneous Nephrolithotomy (PCNL). This technique involves creating a small access through the skin of the flank directly into the kidney. Through this access, an instrument called a nephroscope is introduced to visualize and fragment the stone. PCNL is particularly indicated for stones larger than 2 cm, staghorn stones, or those resistant to other treatments.
Mini-PCNL and Micro-PCNL
To further reduce the invasiveness of the procedure, several variants of traditional PCNL have been developed. Mini-PCNL uses instruments of smaller diameter, resulting in less renal trauma and reduced blood loss. Micro-PCNL involves even smaller access tracts and may be used for moderately sized stones.
Management of Urinary Stone Disease: Importance of a Personalized Approach
Modern management of urinary stones increasingly relies on a personalized approach. The choice of treatment depends on several factors, including stone size, location, composition, urinary tract anatomy, and patient clinical conditions. International guidelines, such as those from the European Association of Urology (EAU), provide clear recommendations to help select the most appropriate therapeutic strategy.
Prevention of Recurrence
An essential aspect of urinary stone management is the prevention of recurrence. Approximately 50% of patients who develop a urinary stone may experience another episode within 5–10 years. For this reason, metabolic evaluation is recommended. Main preventive strategies include increased fluid intake, reduction of dietary salt, moderation in animal protein consumption, and correction of metabolic abnormalities.
The Future of Urinary Stone Surgery
The future will likely be characterized by further technological advances: increasingly miniaturized endoscopic instruments, improvements in laser technologies, integration with robotic systems, and use of artificial intelligence for surgical planning. The main goal remains to make treatments less invasive, more effective, and safer for patients.
Conclusions
Over the past decades, management has undergone a true revolution. Minimally invasive techniques have progressively replaced traditional surgery, allowing the majority of urinary stones to be treated with safe procedures and very short recovery times. The availability of multiple therapeutic options now allows a personalized treatment approach for each patient.
