STONE DISEASE OF THE BILIARY TRACT AND PANCREAS l

Laser lithotripsy - The new wave

J H<..X ·1 !Bl:RUER, MD, C ELL, MD, FRCPC

INCE TIIE EARLY 1980, SEVFR,\L ABSTRACT: Currently more than 90% of all common hile duct concrements can he rcmovcJ via the endoscopic retrograde route hy means of emloscopic Sreams have workeJ on the problem papdlotomy, stone cxlrnction hy haskcts and ballonn catheters, or mechanic::il of fragmentation of gallstones by laser lithntripsy. Oversized, very hard or impacted stones however often st ill resist (I-L9). First reports on the percutane• conventional endoscopic therapy. Laser lithotrtpsy represents a promistng new ous-transhepatic I ichocomy of common endoscopic approach to the nnnsurgical treatment of those common bile duct bile Juct stones c:ame from Jap.u1 u,11lJ! stones. Currently only short-pulsed laser systems with }ugh power peaks but low a continuous wave neodymium YAG potential for thermal tissue damage are used for stone fragmentation. Systems in (NJ: YAG) laser, as 1c is known 111 t'ndo­ clinical applicaunn are the pulsed free-running-mode neodymium YAG scopic tumour trcarment ( 1,2). Maml1, (Nd:YAG) laser (1064 nm, 2 ms) ::iml theJyc laser (504 nm, I to 1.5 µs). Energy melting and drilling effcus on the \tone transmission via highly flexihle 200 µm quart• fibres allows an endoscopic coulendoscopy unit in the scope of the endoscopic pretreatment and does not require L). The advantage of pulsed lasl.'r,com general anesthesia, which is often necessal) for extracorporeal shock wave pared to the continuous wave la,crcon, lithotripsy. Can JGastroenterol 1990;4(9):632-636 sists in the fact that Jue to short pub, duration h 1gh power peaks can be Key Words: Alexandrite laser, Cholel1thia.s1s, Common bile duct, Dye laser, Laser, reached. The pulse energy (Ep, power x Lichocripsy Neodymium YAG laser, Shock wa11es I pulse duration) and the mean power (Pm, pulse energy X pu lse repc11t1on La lithotritie au laser rate), measures fM the thermal poten, tial of the laser arc, however, low. In RESUME: Actuellement, plus de 90% des calculs du cholcdoquc peuvcnt etre L986 common bile duct stonescoulr-Umwrslly, Erlangen -Nuremberg, Germany lithotnptor devices, the cnJoscop1cap­ Correspondence and repnnts: Dr J I lochbcrger, Department of Medicine I, Krankenhaimtr proach and energy application in the I 2, Fricdrich-Alemru1:r University Frlnnien- Nuremb..>ri, D-85 20 bkmgen, Gennany hile duct account for this fact.

632 CAN J GA~TROENTERt)I. VOL 4 No 9 DECEMI\ER Im laser lithotripsy

autorisant l'approchc des calculs par voie retrograde endoscopique, a !'aide d'un For clinical application in gastroen­ duodenoscope conventionnel ou d'un foetoscope. Les nouveaux modelcs terology, the only laser systems at pres­ prescntemcnt utilises !ors des premiers essais cliniques ou des essais prccliniques ent commercially available are pulsed sont le laser NdYAG Q-commute, c'est-a,d1re en foncrionnement a facteur de dye and Nd:YAG lasers. The Alexan­ surtension commute ( 1064 nm, 20 ns), et le laser a alexan

Figure 3} Removal of fine fragments from the Figure 2) Gallstone fragmentation within a few seconds using che millisecond pulse free-running scone surface by laser-induced local shock waves mode Nd:YAG laser with the Q-switched Nd:YAG laser

CAN] GASTROENTEROL VOL 4 No 9 DEC EMBER 1990 633 HOCHBER(,ER ANl1 ELL

Due to high power peaks of the'giant pulses' of the Q-switched Nd:YAG laser, inilially only relatively rigid fi~re transmission syslems could be used. The fibre core diameter was at least 600 µm, and an additional lens focusing syitem or 'light pipes' at the distal fihrc end were needed (12, 13 ). The aulhors have developed a highly flexible iOO µm qu:-1rtz Iight guide system which permits endoscopic retrograde applicat1t>11 ti the Q-switched Nd:YAO laser (14). By giving the distal fibre end a lens-like hemispherical configuration, a foc us area l. 5 to 3 mm in front of the fibre up is obtained. An additional lens focusing system is not necessary. The laser plas­ ma at lhe point of origin of the mechanical shock wave is induceJ Figure 4) Three different ways of applying laser energy to common bile duct concrements: either in front or directly on the surface choledochoscope (left), balloon catheter (centre) with concentric fibre channeL~, and special of the concremem. Stone disintegra­ lithotriptor basket ( right) uon results from the removal of very fine sand grain or powder-like frag, men ts from the stone surface (Figure}) There 1s no hazard of thermal damage lO tissue applying this laser type. In the flash lamp pulsed Jye last:r, organic dyes mostly dissolved in alcohol are used a:. active laser materia l. Depending on the specific dye and the resonator setting, the wavelength of the emttted laser beam can be varied l,e. tween the far ultraviolet and the near infrared (tunahility of wavele ngth). Best light absorplion m gallstones and kidney stones is obtained in the hlue­ green light spectrum ( 4,15,J 6). ForthlS reason, the 504 nm wavelength 1scom• monly applied, wh ich can easily and effectively be generated using cumann dye and which is less absorbed in hemoglobin than in bi lirubin. The high Figure 5) Nonextractable very hard common bile duct concrement in which mechanical l11hotripsy absorption of bi liary concrement~ for had failed several times radiologically before (left) and after laser lithotripsy using ihe luhotr1pwr light of this wavelength facilitate~ the basket; clearly visible fracture line through 1he centre of the stone ( right) induction of a laser plasma with the relatively long microsecond (10-6 s) 9 and laboratory foll ow-up until four gigawatt range (10 W) within five to light pu lses of the dye laser. The frag­ weeks after direct irradiation of the bile 30 ns. However, the pulse energy pro­ mentation process itself is athermal but duct. Histological find ings after that duct of laser power and pulse duration, induced by a thermal process (16,17) time were basically inconspicuous as well as the mean power of the laser After healing a small quantity of ~tone {10,11). Due toils fragmentation are low (Ep 15 to 25 mJ; Pm around 0.3 material at the tip of a 200 µm fi brt mechanism, the free-running mode W). With this laser type, nonlinear opti­ brought inw direct contact with the Nd:YAO laser can be used for gallstones cal processes such as 'plasma' induction stone surface, the plasma and COlbe· but not fo r kidney stones. and creation of a local shock wave can be quently the mechanical shock wave 1s In the Q-switched operation mode, induced. By this methotl a completely induced. The result of fragmentanon 1s the pulsed Nd: YAG laser produces ex­ arhermal transformation of light energy similar to that of the Q-switched tremely high power peaks up to the into mechanical energy is possible (20). NJ:YAO laser. The advantage of the

634 CAN J GASTROENTEROL VOL 4 No 9 DECEMRER 191XJ Loser lithotripsy

type for the fragmentation of biliary calculi arc still limited. A solid state laser like che NJ:YAG, the AlexanJrite laser should be reliable in operation and easy to maintain. Similar to the dye laser 1t is tunable within a certain wave­ length range (700 to 815 nm) but 1s additionally tunahle in pulse durauon (30 to 500 ns in the Q-switched opera­ tion mode). As the laser radiatton emitted is in the deep red and near infrared, low absorption in tissue and therefore little damage is expected. Suf­ ficient absorption 111 stone pigments, however, leads ro a fragmennition effect approximately comparable to that of the pulsed dye laser at equal pulse ener­ gies (9). Because of great loss of quartz material from the fibre tip at short pulse length (250 ns), electronic 'pulse stretching' to the microseconJ range seems to be favorable (19). In virro and animal experiments in rabbits to reveal possible tissue damage to the bile Jucc using the Alexandrite laser are present· ly under way.

CLINICAL APPLICATION At present there are three different methods for endoscopic retrograde ap­ plication of laser lithmripsy in the com­ mon bile duct ( 5-10) (Figure 4 ). If the stone can he caught in a lithotripter ba~ket, iL can be frag­ mented under x-ray control alone; the fibre is centred nghL in the middle of a laser basket by means of a central chan­ nel without any danger of accidental application of energy to ~urrounding tis­ sue (Figure 5). In the case of impacted stones a similar idea is pursued using a balloon catheter with a central chan­ nel. Since x-ray control can usually be Jone only in two planes, a certain in­ security will remain concerning the Figures 6-9) Raaiulogic and choledochoscopic findings before and after laser lichompsy of a giant correct energy application even if bal­ common bile duct concremcnt with visualization of che incral1epauc bile ducts after successful stone loon catheLers are developed which are Yc'lllOVal better adapted to the anatomical situa­ tion. Without any doubt, the safest ap­ dye laser lies in its simple fibre transmis­ technical problems in the routine clini­ proach for stone fragmentation is the sion system, corresponding co that of cal use of the dye laser are dye stability, use of a 'baby' or 'mini' endoscope the free-running mode Nd:Y AG la~er dye change, handling of toxic waste which is inserted into the bile duct via and the use of low pulse energies (E11 30 disposal and electronic failures. a 'motherscope'. The disadvantage of to 90 mJ; Pm 0.3 to 1.3 W). Contrary to The Alexandrire laser represents a the so far commercially existing the nanosecond pulse Q-sw1tch new and interesting device for the mother-babyscope systems is, however, Nd:Y AG, the dye laser can induce ther­ lithotripsy of urinary and biliary calculi that they are fragile and their applica­ mal tissue damage. Currently existing (9,18,19). Experiences using this laser tion is not always simple depending on

CAN J GA~TROENTEROL VOL 4 No 9 DECEMBER 1990 635 H(X'HBERGER AND ELL

the anatomical situation of the bile must be miniaturized or modified for use Electrohydraulic lithocripsy is a very duct. over standard duodenoscopes. Different effective method for the disintegration developments and activities of laser of very hard or giant biliary calculi (21). CONCLUSIONS companies or manufacturers of endo­ Nevertheless, there is always a potential Extracorporeal shock wave litho­ scopy equipment are promising. for tissue Jamagc up to imme

REFERENCES terns: Alexandrite-, dye-, free-running 45. I. Orii K, Nakahara A, Talcase Y, mode neodym YAG- and Q-switcheSurgery Thieme Publishers, 1990. 1988;2:4 3-7. 1981 ;90: 120-1. 10. Ell C. Laserlithotripsie von Gal­ 19. Engelhardt R, Brinkmann R, Meyer 2. Orii K, Ozaki A, Takase Y, Iwasaki Y. lensteinen. In vitro-und tierexperirnen­ W, Walling), Heller D. Urinary and Lithotomy of intrahepatic and relle Untersuchungen. Stuttgart: biliary stone fragmentation wirh the choledochal stones with YAG laser. Ferdinand Enke Publishers, 1988. Alcxandrite-Laser. lnternational Con­ Surg Gynecol Obstet 1983; 156:485-7. 11. Ell C, Hochherger J, MUiier 0, er al. gress and Workshop on Laserlithotnp­ 3. Mills T, Swan P, Watson G, Bown SO, Laserlirhompsy of gallstones by means sy and Conventional Therapy of Salmon PR. Comparison of thermal of a pulsed neodymium YAO-laser - In Urinary and Biliary Stone Disease. Sep,­ and photoacoustic fragmentation of vitro and animal experiments. tember, 1989, Lubeck, Federal biliary calculi using continuous wave Endoscopy 1986;18:92-4. Republic of Germany. (Abst) and giant pulse lasers. Laser Surg Med 12. Ell C, Wondrazek F, Frank F, 20. Boulnois J. Photophysical proces.,L-s m 1983;3: 156. (Abst) Hochberger J, Lux G, Demlmg L. recent medical laser developments: A 4. Watson 0, Jaccques S, Dretler S, Laser-induced shockwave lithotripsy of review. Lasers Med Sci 1986;!:47-66. Parrish J. Tunable pulsed dye laser for gallstones. Endoscopy 1986;18:144-5. 21. Classen M, HagenmUtler F, Knyrim I(, fragmentation of biliary calculi. Laser 13. Schmidt-Kloiber H, Reichel E, Frimberger E. Giant bile duct sronc,­ Surg Med 1985;5:189. (Absc) Schoffmann H. Lasennduccd shock­ Non-surgical treatment. Endoscopy 5. Lux G, Ell C, Hochberger J, MUiler D, wave lithotripsy (LISL). Biomed 1988;20:21-6. Demling L. The first successful endo­ Technik 1985;30:173-81. 22. Saucrbruch T, Stem M. Fragmentataon:, scopic retrograde laser l ithotripsy of 14. Hochberger J, Ell C, Gruber E, et al. of bile duct stones by extraCOTJXircal common bile duct stones in man using Laserlithotripsy of biliary calculi by shock waves. Gastroenterology a pulsed neodymium YAG-laser. means of a Q-switched giant pulse l 989;96: 146-52. Endoscopy 1986;18: l 44-5. Nd:YAG laser and highly flexible fiber 23. Koch H, Stolte M, Walz V. Endo­ 6. Ell C, Lux, G, Hochberger J, Muller D, systems. Gastroenterology scopic lithotripsy in the common h1le Demling L. Laserlithotripsy of common 1989;96:A213. (Abst) duct. Endoscopy 1977 ;9:95-8. bile duct stones. Gut [988;29:746-5 l. 15. Nishioka N, Anderson R. Fragmenta­ 24. Liguory CL, Bonnel D, Canard JM, 7. Kozarek RA, Low DE, Ball TJ. Laser­ tion of biliary calculi with tunable dye Comud F, Dumont JL. lntracorporeal lithorripsy of large bile duct stones. lasers. Gastroenterology 1986;32: 15 7. electrohydraulic shock wave lithompsy Gasrrointest Enclose l 988;28:418-21. (Abst) of common bile duct stones. 8. Cotton PB, Kozarek RA. La:.er 16. Nishioka N, Levins P, Murray S, Endoscopy 1987;19:237-40. lichotripsy of large bile duce stones Parrish J, Anderson R. Fragmentation 25. Kellett MJ, WickhamJEA, Rus.,;ell under direct vis10n via peroral of biliary calculi with tunable dye RCG. Percutaneous cholecysto, choledochoscopy. Gut 1988;29: 1496. lasers. Gasrroenterology l 987;93:250-5. lithotomy. Br Med J I 988;296:453-5. (Abst) 17. Nishioka NS, Teng P, Deutsch TF, 26. Wenk H, Thomas S, Schmellcr N, 9. Hochberger J, Wisbacher R, Gruber E, Anderson R. Mechanism of laser­ Lange V, Schildberg FW. Percutaneo11 Hahn EG, Ell C. Lithotripsy of induced fragmentation of urinary and cranshepatic cholecysto-lithotrip,y gallstones using four different laser sys- biliary calculi. Lasers Life Sci 1987;231- (PTCL). Endoscopy [989;21:221-2.

636 CAN J GASTROENTEROL VOL 4 No 9 DECEMBER 1990 M EDIATORSof INFLAMMATION

The Scientific Gastroenterology Journal of Research and Practice Diabetes Research Disease Markers World Journal Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014

Journal of International Journal of Immunology Research Endocrinology Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014

Submit your manuscripts at http://www.hindawi.com

BioMed PPAR Research Research International Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014

Journal of Obesity

Evidence-Based Journal of Stem Cells Complementary and Journal of Ophthalmology International Alternative Medicine Oncology Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014

Parkinson’s Disease

Computational and Mathematical Methods Behavioural AIDS Oxidative Medicine and in Medicine Neurology Research and Treatment Cellular Longevity Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation Hindawi Publishing Corporation http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014 http://www.hindawi.com Volume 2014