Laser Induced Shock Wave Lithotripsy Research Articles

970: Laser Induced Shockwave Lithotripsy (LISL): In Vitro Comparison of 5 Different Clinical Laser Systems

You have accessJournal of UrologyModerated Poster 29, Monday, May 21, 2007, 1:00 - 3:00 pm1 Apr 2007970: Laser Induced Shockwave Lithotripsy (LISL): In Vitro Comparison of 5 Different Clinical Laser Systems Markus J. Bader, Volkmar Hecht, Derya Tilki, Armin J. Becker, Christian G. Stief, and Ronald Sroka Markus J. BaderMarkus J. Bader More articles by this author , Volkmar HechtVolkmar Hecht More articles by this author , Derya TilkiDerya Tilki More articles by this author , Armin J. BeckerArmin J. Becker More articles by this author , Christian G. StiefChristian G. Stief More articles by this author , and Ronald SrokaRonald Sroka More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)31198-4AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "970: Laser Induced Shockwave Lithotripsy (LISL): In Vitro Comparison of 5 Different Clinical Laser Systems." The Journal of Urology, 177(4S), p. 321 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 177Issue 4SApril 2007Page: 321 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Markus J. Bader More articles by this author Volkmar Hecht More articles by this author Derya Tilki More articles by this author Armin J. Becker More articles by this author Christian G. Stief More articles by this author Ronald Sroka More articles by this author Expand All Advertisement Loading ...

Risk factors for symptomatic stone recurrence after transpapillary laser lithotripsy for difficult bile duct stones using a laser with a stone recognition system

Laser-induced shock-wave lithotripsy (LISL) is successfully used for the treatment of difficult bile duct stones. The aim of this study was to assess the long-term risk for a symptomatic bile duct stone recurrence after LISL and to detect risk factors predicting recurrence. Between 1993 and 2001, 80 patients with difficult bile duct stones were successfully treated by intracorporeal LISL through the papilla of Vater. Seventy-one of these patients [median age, 65.8 years; 51 women (71.8%)] were followed for a median (range) period of 58 (1-114) months. Eleven patients (15.5%) had a symptomatic stone recurrence. The median (range) period between laser lithotripsy and recurrence was 40 (5-85) months. The presence of a bile duct stenosis (P=0.032) and a body-mass index below 25 (P=0.025) were significantly associated with an increased risk for stone recurrence. A gallbladder in situ, the presence of gallbladder stones, dilation of the bile duct, or a peripapillary diverticulum was not associated with stone recurrence. The presence of a bile duct stenosis is significantly related to bile duct stone recurrence after treatment with LISL. The impact of the body mass index on stone recurrence is interesting. The gallbladder status did not predict stone recurrence in our study.

Advances in Therapeutic Endoscopic Treatment of Common Bile Duct Stones

Advances in cannulation techniques and instruments have helped in difficult bile duct cannulation and thus stone extraction. For small common bile duct (CBD) stones, endoscopic papillary balloon dilatation has been proposed as an alternative to endoscopic papillotomy (EPT). The technique must undergo further evaluation before recommending its routine use. For most patients with bile duct stones, EPT remains the method of choice. Out of 8204 patients treated in three surgical endoscopy centers (Chile, Germany, and India), 86% to 91% of all CBD stones could be extracted subsequently after EPT using a Dormia basket; 4% to 7% required mechanical lithotripsy (ML) before removal and 3% to 10% of the patients needed other sophisticated techniques, such as electrohydraulic lithotripsy (EHL), laser-induced shock-wave lithotripsy (LISL), or extracorporeal shock-wave lithotripsy (ESWL). The local expertise and availability of equipment determines the choice of method used. In general, EHL or LISL is used for impacted CBD stones including stones in Mirizzi syndrome refractory to ML. ESWL is best suited for intrahepatic stones. Permanent stenting can be offered to poor risk patients instead of extensive procedures to clear the bile duct. Using currently available nonsurgical techniques, fewer than 1% of all patients with bile duct stones still require surgical intervention.

Miniature endoscopes in otorhinolaryngologic applications

SummaryProgressive miniaturization of rigid and flexible endoscopes enables the practising otorhinolaryngologist (head and neck surgeon) to visually inspect regions of the upper respiratory tract that could never have been inspected directly before, or had only been accessible for direct view by massive traumatization of the anatomic surroundings. For the otologist, microendoscopy opens up the possibility of using an endoscope to assess the luminal situation of the Eustachian tube, in order to detect morphological obstructions of this normally collapsed connection between the middle ear compartment and the nasopharynx. The first basic laser surgery on polyps and oedematous soft tissues to restore the essential proper ventilation and drainage of the tympanic cavity have been performed and data about this topic are soon to be published. The ‘mother-baby endoscope’ technique allows us to reach into the nasopharynx and paranasal sinuses via the natural orifices, for a direct visual diagnosis of chronic secretory and polypous rhinosinusitis. Even small recurrences can be treated using minimally invasive techniques by fibre-delivered laser surgery in hidden areas of facial skull cavities. This painless technique is particularly useful in children. The development of ‘sialendoscopy’ i.e. microendoscopy of the salivary glands, is the first procedure to identify the real cause of obstructive disorders of the major salivary glands. Direct visual inspection allows the examiner to differentiate between stenoses, secretion plugs and calculi. In cases of sialolithiasis, laser-induced shock wave lithotripsy (LIL) can be performed by transferring short laser pulses via an inserted fibre onto the surface of the stone to disintegrate it.

Pulsed dye laser lithotripsy of submandibular gland salivary calculus.

An in vivo study was performed to evaluate the use of pulsed-dye laser beam for the fragmentation of salivary calculus. In accordance with the absorption and reflection spectra of sections of salivary stones, optimal fragmentation was achieved with a pulsed-dye laser with a pulse width of 1.4 microns and tuned to a wavelength of 504 nm. Further studies on particle size were conducted, and a new "sialoendoscope" technique was developed. Fifteen patients with sialolithiasis of the submandibular gland were treated. Under continuous endoscopic monitoring laser-induced shock wave lithotripsy was performed. In six patients complete fragmentation and removal of the salivary stones was achieved and in another patient 50 per cent fragmentation was sufficient to restore salivary flow. Laser lithotripsy of salivary stones with endoscopic monitoring permits treatment on an outpatient basis with little inconvenience to the patient, and this is a breakthrough in otolaryngology.

唾石の内相鏡下レーザー破砕術の試み

The application of laser beams for the fragmentation of salivary stones was examined. Studies of the absorption and reflection spectra of sections of salivary stones showed that optimal fragmentation was achieved with a pulsed dye laser with a pulse width of 1.4 psec and a wave-length of 504nm. Further studies of particle size were conducted, and a new “sialoendoscope” technique was developed. Two patients with a sialolithiasis of the submandibular gland were treated. Under continuous endoscopic monitoring, laser-induced shock wave lithotripsy was performed. In one patient complete fragmentation and removal of the salivary stones was achieved and in the other 70% fragmentation was possible, and salivary flow was restored. This approach to laser lithotripsy of salivary stones with endoscopic monitoring represents a novel method that permits treatment on an outpatient basis under local anesthesia with little inconvenience to the patient.

ESWL and the future of stone management

Based on optimal efficacy regarding disintegration and stone clearance, combined with minimal invasiveness, extracorporeal shockwave lithotripsy (ESWL) represents the first choice therapy for urolithiasis. Further developments in ESWL have related more to economic aspects than to improvement of disintegration efficacy or reduction of side effects. Routine indications for ESWL are well known and widely accepted. Its limitations are also well established: silent calyceal stones, calyceal diverticula stones, nephrolithiasis in horse-shoe kidneys, medullary sponge kidney, and residual fragments after ESWL. Although endourology provides new, less invasive and traumatic means of stone retrieval or disintegration, including laser lithotripsy, small ureteroscopes and actively deflectable uretero- and pyeloscopes, indications for an aggressive approach in such cases are limited to those who are symptomatic. In the case of distal ureteral calculi ureteroscopy in traureteral laser-induced shockwave lithotripsy open up new and interesting possibilities for the future.

Laser-induced shock wave lithotripsy with a regenerative energy converter

Two main mechanisms govern the field of laser lithotripsy. The first mechanism produces mechanical stress inside the stone by absorbing the laser light at the stone surface. Therefore it depends on the stone's optical properties. The second method uses a Q-switched laser and an energy converter to release mechanical shock waves acting on the stone to cause its fragmentation. This method is called laser-induced shock wave lithotripsy (LISL). The converter must be attached to the light transmitting optical fibre and should not provide an increase of the overall diameter of the probe to fit in a small, flexible endoscope. So we used the irrigation liquid, which must be supplied for endoscopic lithotripsy. Adding of Fe3+-ions to the isotonic saline solution (0.02 mmol l−1) lowered the intensity threshold for the energy conversion. With this special irrigation liquid we have a continuously regenerating energy converter. It allows the use of bare fibres with spherically shaped tips, which can be easily changed while the endoscope remains inside the patient's body.

Endoscopic Management of Difficult Bile Duct Stones

More than 90% of all common bile duct concrements can be removed via the endoscopic retrograde route via endoscopic sphincterotomy, stone extraction by baskets and balloon catheters, or mechanical lithotripsy. Oversized, very hard or impacted stones, however, often still resist conventional endoscopic therapy. Promising new or improved approaches for the treatment of these stones are intracorporeal or extracorporeal shock wave lithotripsy. Shockwave lithotriptors for extracorporeal shockwave lithotripsy are currently available worldwide. However, for the waterbath first generation devices, general anesthesia is required since shockwaves are very painful. Furthermore, an x-ray localization system is essential to visualize the stones after having filled the bile duct over a nasobiliary catheter. An average of two shockwave treatments with additional two to four endoscopic sessions are required. ln tracorporeal lithotripsy promises more comfort and less effort for the patient. Shockwaves are generated either by means of the spark gap principle (electrohydraulic probes) or by laser-induced plasma generation. Laser-induced shockwave lithotripsy appears to be more safer, since with dye and solid state lasers, athermal, well-controlled shockwaves can be generateJ without the risks for duct perfo ration (as described for the electrohydraulic system). Furthermore, a recently developed stone-tissue detection system integrated in a new dye laser system enchances the safety of laser-induced lithotripsy. ln consequence, lithotripsy without direct endoscopic control appears possible in selected cases.

Interspersion of fragmented fiber's splinters into tissue during pulsed alexandrite laser lithotripsy

Laser induced shockwave lithotripsy (LISL) on artificially inserted human renal calculi was realized in explanted pig ureters. A pulse stretched Alexandrite solid state laser was used at 750nm. Pulses of 350ns and 1 microseconds duration were transmitted through a 250 microns all silica fiber onto a stone surface, keeping the fiber tip in contact with a stone close to the ureter wall. The high power density of the 350 ns pulses lead to an optical breakdown inside the distal fiber tip causing fiber fragmentation of about 28 mm/100 pulses. Deep penetration of the fiber fragments into the ureter wall was proven histologically. Fiber fragmentation was avoided by increasing the pulse duration up to 1 microseconds. Riks for patient treatment caused by short pulse lithotripsy are discussed.

Application Systems for Intracorporeal Laser-Induced Shockwave Lithotripsy Using the Nd:YAG Q-Switched Laser

Application Systems for Intracorporeal Laser-Induced Shockwave Lithotripsy Using the Nd:YAG Q-Switched Laser

Application systems for intracorporeal laser-induced shockwave lithotripsy using the Nd:YAG Q-switched laser.

For laser-induced shockwave lithotripsy, the electromagnetic energy of a laser light pulse is converted intracorporeally into the acoustic energy of a shockwave. The lithotriptor is based on a specially developed, Q-switched Nd:YAG laser whose high power light pulses (70 mJ, 25 nsec) are coupled into a flexible quartz fiber with a core diameter of 600 mum. Using focusing elements, energy densities higher than 6 x 10 5 J m -2 can be achieved, resulting in an optical breakdown in water followed by a shockwave. As a result of different absorption mechanisms, the breakdown threshold can be decreased by placing a metallic target into the laser beam. The different shockwave formations of such optomechanical transducers have been measured. First clinical applications have been performed.

Laser-induced shock wave lithotripsy

With a high intensity Q-switched Nd-YAG laser shock waves can be generated in a liquid close to the calculus. Up to 80 mJ single pulse energy with 8 nsec pulse duration can be transmitted through flexible quartz fibers. Energy conversion and enhancement can be accomplished at the fiber tip with optical focussing of the light at the quartz tip, with irrigation solutions and with high pulse energies. Iron-III-dextran solutions (1 mg Fe3+/1) and magnesium chloride (50 mmol/l) increased the pressure in the laser induced breakdown up to ten times (8,000-10,000 bar). Smaller stone particles and higher efficacy in stone fragmentation could be achieved.

Laser Lithotripsy: Further Experience with Nd:YAG Laser

Fifteen patients with ureteral stones underwent attempted laser-induced shock wave lithotripsy. Shock waves were generated by a pulsed Q-switched NdrYAG laser (8-12-nsec pulses, 1064-nm wavelength). The transmission system consisted of a 600-μm fiber mounted with a newly developed optomechanical coupler. Complete fragmentation of the stones occurred in 11 patients. Partial fragmentation occurred in three patients, and in one patient, the laser failed to fragment the stone. Laser lithotripsy succeeded in four patients using only fluoroscopic control without ureteroscopy. In a trial to optimize the technique, we report our initial experience with the new transmission system.

Laser-induced shock-wave lithotripsy of ureteric calculi

Laser-induced shock-wave generation with a high-intensity Q-switched Nd: YAG laser depends on a laser-induced breakdown in a liquid, with the formation of an oscillating plasma bubble and cavitational effects. No thermic lesions in porcine urothelium could be found. A new multifunctional laser for shock-wave fragmentation (20-ns pulse duration) of urinary calculi, with a freerunning mode and millisecond pulses for biliary stones and coagulation of tissue was developed for use with 320-, 400- and 600-μm quartz fibers. A total of 100 patients with 112 calculi were treated with laser-induced shock-wave lithotripsy (LISL), with complete fragmentation of 106 stones; in 6 calculi, laser disintegration was too slow. The efficacy of LISL can be augmented with a highly diluted metallic solution (Fe-III-dextran or MgCl) by a self-focussing effect of the laser beam. With small quartz fibers 320 and 400 μm, however, these solutions are not necessary for hard stones, as the laser focus is minimized in these fibers.

Laser induced shock wave lithotripsy

AbstractLaser induced shock wave lithotripsy has the potential to become a standard procedure in the endourologic management of urinary stone disease. To date, there are two fairly well established laser systems for laser induced shock wave lithotripsy in clinical practice, the Q‐switched Nd: YAG and the flashlamp pumped dye laser. —The Q‐switched Nd: YAG Laser (20 ns pulses) is distinguished by the high stone selectivity of its coupler systems, but the necessity of a coupler and its fairly small rate of conversion of light into mechanical energy present a grievous draw back. Furthermore, the minimal outer diameter of the transmission system is 1.8 mm, limiting its range of application. —By using longer pulses in the range of 1–2 μs that can be produced with both a flashlamp pumped dye or a low‐gain solid state laser with the same pulse energies (∽ 50 mJ) these disadvantages can be overcome. —Pulses of the dye laser can be passed through a highly flexible and uncomplicated 200 μm quarz fiber. Laser lithotripsy is performed with the bare fiber tip placed directly in contact with the stone at repetition rates of up to 10 Hz. The quality of the fiber tip in contact with the stone is uncritical. —Biological evaluation of damage caused by direct irradiation shows that both laser systems cause minor damage of different degree. —Our newest development is a optical feedback regulation system to avoid damage to adjacent tissue even under direct contact, enabling intracorporeal lithotripsy without endoscopic control.

Lasers in urology

Different kinds of laser-tissue interactions have been tested as to their feasibility in urology. Some applications, especially the thermal interactions of tumor destruction have become standard procedures; others, such as laser induced shock wave lithotripsy, promise to become an undisputed method for those urinary calculi elusive to extracorporeal shock wave lithotripsy. Further applicabilities, especially those of tumor diagnosis by laser spectroscopy are still in their infancy and the scope of future developments cannot be estimated at present.

Laser Induced Shock Wave Lithotripsy—Biologic Effects of Nanosecond Pulses

Laser energy of a Nd-YAG laser (1064nm. wave length, 8 nsec pulse duration) was directed against various tissue cultures and the urothelium of the ureter, bladder and kidney parenchyma in pigs. Single pulse energy was 50 to 120mJ with a repetition rate of 20Hz. Urothelium and kidney parenchyma were irradiated in seven pigs. Tissue samples were examined histologically and electron-microscopically directly, two, four, eight and 12 days after irradiation. No macroscopic lesion could be found. Maximum energy caused a small ‘rupture cone’ of 40µm. depth. No thermic effects or necrosis resulted, so that no harm is to be expected with unintentional irradiation during laser stone disintegration.

701 - Laser-Induced Shock Wave Lithotripsy (LISL)

701 - Laser-Induced Shock Wave Lithotripsy (LISL)

Laser-induced Shockwave Lithotripsy of Gallstones

With the aid of a Q-switched Nd:YAG laser with energy transmission via a flexible glass fiber, it proves possible under laboratory conditions, to destroy gallstones reliably and reproducibly. Lithotripsy is effected mechanically via a laser-induced local shockwave.