Laser lithotripsy is a

surgical procedure Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

to remove stones from urinary tract, i.e.,

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

ureter The ureters are tubes made of smooth muscle that propel urine from the kidneys to the urinary bladder. In a human adult, the ureters are usually long and around in diameter. The ureter is lined by urothelial cells, a type of transitional epit ...

bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...

, or

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

History

Laser

lithotripsy Lithotripsy is a non-invasive procedure involving the physical destruction of hardened masses like kidney stones, bezoars or gallstones. The term is derived from the Greek words meaning "breaking (or pulverizing) stones" ( litho- + τρίψω rip ...

was invented at the Wellman Center for Photo medicine at Massachusetts General Hospital in the 1980s to remove impacted urinary stones. Optical fibers carry light pulses that pulverize the stone.

Candela The candela ( or ; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous to ...

licensed the technology and released the first commercial laser lithotripsy system. Initially 504 nm dye lasers were used, then holmium lasers were studied in the 1990s.

Procedure

urologist Urology (from Greek οὖρον ''ouron'' "urine" and ''-logia'' "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the urinary-tract system and the reproductive organ ...

inserts a scope into the urinary tract to locate the stone. The scope may be a

cystoscope Cystoscopy is endoscopy of the urinary bladder via the urethra. It is carried out with a cystoscope. The urethra is the tube that carries urine from the bladder to the outside of the body. The cystoscope has lenses like a telescope or microscope ...

ureteroscope Ureteroscopy is an examination of the upper urinary tract, usually performed with a ureteroscope that is passed through the urethra and the bladder, and then directly into the ureter. The procedure is useful in the diagnosis and treatment of diso ...

, renoscope or nephroscope. An optical fiber is inserted through the working channel of the scope, and laser light is directly emitted to the stone. The stone is fragmented and the remaining pieces are collected in a "basket" and/or washed out of the

urinary tract The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, con ...

, along with the finer particulate "dust." The procedure is done under either

local Local may refer to: Geography and transportation * Local (train), a train serving local traffic demand * Local, Missouri, a community in the United States * Local government, a form of public administration, usually the lowest tier of administrat ...

general anesthesia General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...

and is considered a

minimally-invasive procedure Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition ...

. It is widely available in most hospitals in the world.

Comparison

Laser lithotripsy (LL) has been evaluated against

Extracorporeal An extracorporeal is a medical procedure which is performed outside the body. Extracorporeal devices are the artificial organs that remain outside the body while treating a patient. Extracorporeal devices are useful in hemodialysis and cardiac surg ...

Shock Wave lithotripsy (ESWL), finding both to be safe and effective. ESWL may be safer for small stones (<10 mm), but less effective for 10–20 mm stones. A 2013 meta-analysis found LL can treat larger stones (> 2 cm) with good stone-free and complication rates. Holmium laser lithotripsy had superior initial success and re-treatment rate compared to

extracorporeal shock wave lithotripsy Extracorporeal shockwave therapy (ESWT) is a non-invasive, out-patient alternative to surgery for those with many joint and tendon disorders. ESWT sends acoustic shock waves into bone or soft tissue, in effect reinjuring the area on a cellular l ...

(ESWL) in a 2013 trial. The experimental thulium

fiber laser A fiber laser (or fibre laser in British English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related t ...

(TFL) is being studied as a potential alternative to the holmium:YAG (Ho:YAG) laser for the treatment of kidney stones. The TFL has several potential advantages compared to Ho:YAG laser for lithotripsy, including a four times lower ablation threshold, a near single-mode beam profile, and higher pulse rates, resulting in up to four times as fast ablation rates and faster procedural times.

Lasers

Pulsed dye laser A dye laser is a laser that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths, often spanning 50 to 100 ...

s have been used with fiber diameters of 200–550 microns for lithotripsy of biliary and urinary stones. Ho:YAG lasers have wavelength of 2100 nm (infrared) and are used for medical procedures in urology and other areas. They have qualities of CO₂ and Nd:Yag lasers, with ablative and coagulation effects. Holmium laser use results in smaller fragments than 320 or 365 micron pulsed dye lasers or electrohydraulic and mechanical methods. Thulium fiber lasers are being investigated.

References

{{Lasers Laser medicine Urologic procedures

History

Procedure

Comparison

Lasers

See also

References