Extracorporeal Shockwave Lithotripsy (ESWL) and Advancements In Kidney Stones Treatment

Kidney stones are small hard masses composed of salt and minerals primarily calcium formed inside the kidneys. Between 3-5% of the general population develop kidney stones in their lifetime. Globally, an estimated 4.5 million adults are diagnosed with kidney disease annually. If the kidney stones are less than 4 mm size they can be passed out of the urine easily and if kidney stones are too big to be passed out of the body that is of size 6-7 mm in diameter, then various treatments are used to remove the stones like Extracorporeal shock wave Lithotripsy (ESWL), Ureteroscopy, percutaneous nephrolithotomy (PCNL) and open surgery.

According to IQ4I estimation the global extracorporeal shockwave lithotripsy market is estimated to reach $264 million by 2023. North America holds the largest share in number of units sold and in installed base of the global ESWL market. Rest of the world is expected to grow at a double digit CAGR from 2016 to 2023. The major drivers for the ESWL market are developing healthcare infrastructure, the availability of advanced equipments to carry out the procedures, rising prevalence of obesity and patient awareness. Research studies show that obesity or higher body mass index (BMI) may increase the amount of calcium and other substances in the urine which in turn leads to the formation of kidney stones. Failure of breaking large stones through this device is a challenging factor for the extracorporeal shock wave lithotripsy market.

Extracorporeal shockwave lithotripsy is a non-invasive treatment of kidney stones and gallbladder stones. Major principle behind the treatment is breaking of the kidney stones by passing shock waves from outside the body targeted at kidney stones. Stones that are between 4 mm (0.16 in.) and 2 cm (0.8 in.) in diameter are most likely to be treated with ESWL used at rate of 60-90 shocks/minute to achieve optimal stone fragmentation.

The basic components of ESWL machines are shockwave generator or lithotripter, a focusing system, a coupling system and imaging/localization unit. The shockwaves used in the treatment can be generated in 3 ways such as by Electrohydraulic, Piezoelectric and Electromagnetic. In the electrohydraulic generator, the passing of electric current through the electrodes generates the high-energy pressure waves that are used as shock waves for the treatment, whereas, in Piezoelectric generator, the piezoelectric ceramics or crystals are being mechanically stressed by high-frequency electrical pulses resulting in the production of shock waves. In an electromagnetic generator, high-frequency vibrations which are produced by electromagnetic coil under high voltage produces shockwaves used for the breaking the kidney stones.

The focusing system in the ESWL treatment uses the generator produced shockwaves which are at one focal point (F1) and unites at the second focal point (F2). The focusing systems can be of different shape like an ellipsoid, hemispherical or cylindrical depending on the types of the generator used. The coupling system usually consists of small water drums/cushions and the major purpose of using coupling system in the treatment is to reduce the dissipation of energy of shockwaves before reaching into the patient’s skin surface. Imaging systems provides us with the exact location and visualization of the kidney stone. Fluoroscopy and ultrasonography are the two visualization techniques used to locate stones, wherein, ultrasonography is the cost effective and most efficient technique in comparison with the fluoroscopy.

ESWL is being used in new applications such as chronic calcification like heel spur, treating pancreatic stone, gallstones, Peyronie’s disease and erectile dysfunction. The key advantages of this technology are it does not require any anesthesia or hospital admission and almost 80% of all stones can be treated quite safely. However, there are few disadvantages like, this treatment is not suitable for the larger kidney stones and more sessions are required for the fragmentation of the larger stones, the passage of stones may results in acute colic, pain and discomfort in the patient and the treatment cannot be used for a pregnant woman. Sometimes ESWL might cause urinary tract infection.

Uretereoscope, a surgical procedure of removing the stone can be an alternative to ESWL and proved to be efficient in comparison with ESWL in terms of stone clearance rate and fewer repeated treatments. Michael Bailey, principle engineer in UW’s (University of Washington) Applied Physics, U.S and his team developed a new technology called Burst Wave Lithotripsy (BWL) which can pose a threat to ESWL technology in future. In Burst Wave Lithotripsy, focused ultrasound is used to fragment the larger kidney stones into uniform, small fragments and allowing them to pass naturally. BWL is still in the preclinical stage and can move into a clinical trial in a couple of years.

With the advancement in imaging technologies and predictive healthcare, the future of both technologies looks promising. However, the preferable choice to treat the kidney stones would depend on several factors like the nature of stones, patient condition and their response to the treatment option ESWL or Ureteroscopy.

Some of the major players in global ESWL market are Boston Scientific (U.S), Cook Group (U.S), C. R Bard (U.S), Dornier MedTech GmbH (Germany), Karl Storz (Germany), Lumenis (Israel), Medtrue Enterprise Co. Ltd (China), Olympus corporation (Japan), Siemens AG(Germany)


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