The Evolution of Stone Treatment: From War Zones to High-Tech Healing

Last updated: August 17, 2026

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Welcome to a journey through the history and science of one of the most transformative technologies in modern urology: Extracorporeal Shockwave Lithotripsy (ESWL). As a board-certified urologist specializing in kidney stone treatment, I want to share with you how a wartime observation evolved into one of the most elegant non-invasive procedures we offer today.

This article is drawn from my official presentation delivered at the Royal Phnom Penh Urology Seminar on November 17, 2018. That seminar remains a meaningful milestone in my career — a moment where we connected the historical roots of medical innovation to the cutting-edge solutions I now provide to patients at Bangkok Hospital Headquarters and Samitivej Sriracha Hospital.

Before the History: When a Stone Becomes an Emergency

This article is about technology, and technology is the least urgent part of stone disease. Before reading on, it is worth knowing which stone situations cannot wait, because the answer to them is not a lithotripter appointment:

• Fever or shaking chills with flank pain. This suggests an infected, obstructed kidney — the true emergency of stone disease. It needs urgent drainage of the kidney, not antibiotics alone, and it can become life-threatening within hours.
• Passing little or no urine, or severe pain in a man with a single functioning kidney or a transplanted kidney.
• Pain with persistent vomiting that prevents you keeping fluids down.
• Suspected stone in pregnancy, which needs assessment by a team rather than a standard pathway.

In Thailand the emergency number is 1669. Everything below assumes you are not in one of these situations.

What Exactly is a Shockwave?

To understand how we break kidney stones without a single incision, we must first understand the physics of the shockwave. In scientific terms, a shockwave is a sharp change of pressure in a narrow region traveling through a medium such as air or water. These waves are typically caused by explosions or by bodies moving faster than the speed of sound.

In urology, we harness this energy and aim it with precision. Think of it like a focused beam of sound energy: much like a magnifying glass focuses sunlight onto a single point to create heat, an ESWL machine focuses shockwaves onto a kidney stone to create mechanical stress, eventually shattering the stone into dust or small fragments that can be passed naturally in the urine.

A Surprising History: From Battlefields to Hospitals

The history of ESWL is a classic example of dual-use technology — where a discovery in one field changes another entirely.

• The World War II Connection: During WWII, it was observed that sailors and soldiers in the vicinity of underwater depth charge explosions suffered severe lung injuries — even when they had no visible external wounds. This proved that shockwaves could travel through water and the human body to affect internal structures.
• The Breakthrough (1980): Decades of research into high-energy physics eventually led to a medical breakthrough. On February 7, 1980, the very first human treatment using a first-generation Extracorporeal Shockwave Lithotripter was performed in Germany. This single event changed urology forever, transforming what used to be major open surgeries into non-invasive procedures.

The Four Generations of ESWL

The technology has evolved rapidly since 1980. Each generation of machines has aimed to make the treatment safer, more comfortable, and more accurate. One caution before the list, because it is easy to read a story of generations as a story of steadily better results: what improved most across the generations was comfort, size, cost and targeting. Stone clearance itself has not improved in the same straight line, and the characteristics of your stone matter more than the age of the machine.

1. The First Generation: The Water Bath Era

The early machines were massive. To work, the patient had to be submerged in a large tub of water to allow the shockwaves to travel from the generator into the body. The downsides were significant: these machines were incredibly expensive and huge, the focal zone (the area where the energy hits) was wide and therefore less precise, patients required general anesthesia, and they typically required hospitalization.

2. The Second Generation: The Dry Patient

Engineers replaced the giant water tub with a small water-filled cushion or bellows pressed against the patient’s skin. The patient stayed dry, and the focal zone became tighter and more accurate. Some treatments could be done under local anesthesia — but the machines remained large and still required significant radiation exposure for stone targeting.

3. The Third Generation: Compact Efficiency

These machines became much smaller and more mobile. However, they still relied heavily on X-ray (fluoroscopy) for targeting, meaning patients were exposed to radiation. Furthermore, the patient’s breathing caused the kidney stone to move up and down with each respiration, making it difficult to maintain a perfect hit rate on the stone. This is the generation in use at Bangkok Hospital Headquarters today, and it remains a thoroughly established treatment — the large majority of the world’s published ESWL evidence was generated on machines of this type.

4. The Fourth Generation

This generation represents a real advance in targeting and patient comfort. I introduced Cambodia’s first 4th-generation lithotripter at Royal Phnom Penh Hospital in 2018, after training on the system at Chang Gung Memorial Hospital in Taiwan. At Bangkok Hospital Headquarters, ESWL is currently performed using a 3rd-generation lithotripter. The improvements of the 4th generation are these:

• Automated stone localization: the system assists in finding and holding the target.
• Radiation-free targeting: ultrasound rather than X-ray can be used to locate the stone, so a session can be completed without radiation exposure. In practice X-ray is still used in some cases, for example where the stone is not clearly seen on ultrasound.
• Respiratory tracking: the ultrasound system follows the stone as it moves with the patient’s breath, so more of the shockwaves land on the target rather than on surrounding tissue.
• Less need for anesthesia: many patients tolerate treatment with little or no analgesia and return home the same day. This is about comfort during the session; it does not by itself mean more stones are cleared.

What Determines Success?

Whichever generation of lithotripter is used, whether a stone breaks depends far more on the stone than on the machine:

Factor	Description
Stone hardness	Not all stones are alike. CT scanning measures stone density in Hounsfield Units. Dense stones — calcium oxalate monohydrate and cystine in particular — resist shockwaves and may not fragment at all, whichever machine is used.
Stone location	Stones in the kidney or upper ureter generally do better than those in the lower pole, where fragments must travel uphill to leave the kidney and often simply stay there.
Stone size	Stones under 10 mm do best. Above 10 mm, a single session clears fewer stones and a second treatment is more often needed.
Body habitus	The distance from skin to stone matters. Where that distance is large, the shockwave arrives with less energy and success falls — which is why ESWL is not the right choice for every patient.

A note on the success figures quoted for ESWL, including on this site in the past. Published rates for stones under 10 mm are often given as roughly 85–90%, but those numbers move a great deal depending on what is being counted. Being stone-free on a CT scan is a far stricter test than having no fragment larger than 4 mm, and studies use both. Density, location and skin-to-stone distance shift the figure further. The honest way to use a published rate is as a starting point for a conversation about your own stone, not as a promise.

What ESWL Asks of You: Risks and Aftermath

Non-invasive does not mean without consequence, and a history of the technology would be incomplete without saying what the treatment actually involves for a patient. Expected effects in the days afterwards include blood in the urine, bruising or tenderness of the skin over the treated side, and colicky pain as fragments make their way down the ureter — that pain can be worse than the original stone, and it is normal rather than a sign of failure.

The complications worth knowing about are:

• Steinstrasse — literally a street of stones: fragments lining up and blocking the ureter. Increasing pain, or any pain accompanied by fever, after treatment needs assessment rather than waiting.
• Infection, including sepsis from bacteria released as the stone breaks up. This is why a urine infection is treated before treatment, never during it.
• Bleeding around the kidney (perirenal haematoma) — uncommon, and more likely with uncontrolled blood pressure or a bleeding tendency.
• Incomplete fragmentation, needing a second session or a change of plan to ureteroscopy.

ESWL is not suitable for everyone. It is avoided in pregnancy, with an untreated urinary infection, with a bleeding disorder or anticoagulation that has not been managed beforehand, where there is an obstruction below the stone that would prevent fragments passing, and where an aortic or renal artery aneurysm sits in the shockwave path. Whether you can safely pause a blood thinner is a decision for the doctor who prescribed it, together with your urologist — never a decision to make on your own.

What happens after treatment is set out in detail in my patient instructions for 3rd-generation ESWL, which is the machine used at Bangkok Hospital Headquarters. And because breaking a stone is not the same as solving the problem, the more important half of stone care is preventing the next one — and for one stone type in particular, medication can dissolve the stone rather than break it.

Final Thoughts

The evolution of ESWL — from a wartime observation to a 4th-generation tracking system — is a testament to the power of medical innovation. My presentation in 2018 at Royal Phnom Penh Hospital was, in many ways, a celebration of this progress. But the lesson I took from it, and still hold, is that the machine is the least interesting variable. Whichever generation of lithotripter is used, ESWL remains a non-invasive, same-day treatment that allows most patients to return to normal life quickly — and careful patient selection matters far more than the age of the equipment. At Bangkok Hospital Headquarters, ESWL is performed using a 3rd-generation lithotripter, with candidates selected on the basis of stone size, location, density and body habitus. For stones that ESWL cannot handle well, flexible ureteroscopy with holmium laser (RIRS) is generally the better answer.

If you are dealing with kidney stones and would like to discuss which treatment is right for you, Dr. Soarawee Weerasopone provides specialist kidney stone care at Bangkok Hospital Headquarters and at Samitivej Sriracha Hospital, Chonburi — 088-022-1445.

Bangkok Hospital Telemedicine is available for patients who cannot attend in person, including international patients — arrange it in advance by email to the Urology department at bhquro@bdms.co.th. Samitivej Sriracha is in-person only. For any enquiry about the cost of consultation or treatment, please contact the hospital directly — Bangkok Hospital at bhquro@bdms.co.th, or Samitivej Sriracha on 088-022-1445.

Frequently Asked Questions About ESWL

What is ESWL and how does it break kidney stones?

ESWL (Extracorporeal Shockwave Lithotripsy) uses focused shockwaves generated outside the body to break kidney stones into small fragments. The shockwaves pass through the skin and tissue, concentrating their energy on the stone to fracture it into pieces small enough to be passed naturally in the urine.

What are the risks of ESWL, and when should I seek help after treatment?

Blood in the urine, skin tenderness over the treated side and colicky pain as fragments pass are expected in the days afterwards. The complications to know about are steinstrasse (fragments blocking the ureter), infection including sepsis, bleeding around the kidney, and incomplete fragmentation needing a further session. Seek care urgently for fever or shaking chills, pain that is escalating rather than settling, persistent vomiting, or passing little or no urine. In Thailand the emergency number is 1669.

Who should not have ESWL?

ESWL is avoided in pregnancy, with an untreated urinary infection, with a bleeding disorder or anticoagulation not managed in advance, where an obstruction below the stone would stop fragments passing, and where an aortic or renal artery aneurysm lies in the shockwave path. Very dense stones and a large skin-to-stone distance also make ESWL a poor choice, and flexible ureteroscopy with holmium laser is often better in those situations. Never stop a blood thinner on your own — that decision belongs to the doctor who prescribed it.

Is ESWL painful or does it require anesthesia?

ESWL is generally well tolerated and is performed as a same-day procedure. How much pain relief is needed depends partly on the machine: with 4th-generation systems many patients need no anesthesia at all, while with 3rd-generation lithotripters — including the one used at Bangkok Hospital Headquarters — short-acting intravenous analgesia or light sedation is commonly given. In either case, patients normally return home the same day.

What size of kidney stone is best treated with ESWL?

Stones under 10 mm respond best. Published success rates for this group are often quoted around 85–90%, but the figure depends heavily on how success is defined — being completely stone-free on CT is a much stricter test than having no fragment above 4 mm — and on stone density, position and skin-to-stone distance. Stones above 10 mm may still respond but more often need a second session or a different approach.

Does modern ESWL still use X-ray radiation?

It depends on the generation of the machine. Fourth-generation systems can localize the stone with ultrasound and complete a session without X-ray, although fluoroscopy is still used in some cases where the stone is not clearly visible. Third-generation lithotripters — including the one used at Bangkok Hospital Headquarters — rely on X-ray fluoroscopy for targeting, although exposure is brief and kept as low as reasonably achievable, and the dose is comparable to routine diagnostic imaging.

Is a newer machine always better?

Not in the way the word generation suggests. What improved most across the four generations was patient comfort, machine size and cost, and the accuracy of targeting. Stone clearance did not improve along the same straight line, and it depends far more on the density, size, position and depth of your particular stone. A well-selected patient on a 3rd-generation machine will do better than a poorly selected one on a 4th-generation machine.

Disclaimer: This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters. It is intended for educational purposes only and does not constitute medical advice. No diagnosis, advice or prescription is provided through personal messaging channels or social media. Always consult a qualified healthcare professional before starting, stopping or changing any medical treatment.