Endoscopic pulsed dye laser lithotripsy of gallbladder calculi in vivo.

We have evaluated the efficacy and safety of pulsed dye laser lithotripsy of gallbladder calculi using a percutaneous endoscopic technique in a porcine model. Fragmentation was readily achieved in vivo. Using a combination of laser lithotripsy and saline lavage, complete removal of all stone debris was feasible through a 24 F tract (N = 3). However, the degree of fragmentation required rendered removal through a smaller tract inefficient, a mean 53% of stone mass being retrievable through a 16 F tract (N = 11). Repeated laser activation at 1 mm from the gallbladder mucosa produced minimal injury, regardless of pulse energy. When the laser fiber was pressed against the mucosa, perforation of the gallbladder was possible at therapeutic pulse energy, but this did not lead to clinical sequelae. We conclude that the pulsed dye laser is a safe and effective means of fragmenting gallbladder calculi in vivo.     

Percutaneous transhepatic cholangioscopic color laser lithotripsy in bile duct calculi]

Tunable dye laser lithotripsy is an effective and low risk treatment in patients with bile duct stones in which transpapillary maneuvers failed. The percutaneous approach allows to introduce small caliber endoscopes (10.5 F) to fragment the calculi under vision. This technique was evaluated in 8 patients who had undergone a biliodigestive anastomosis or in whom the biliary calculi could not removed by standard retrograde treatment. Laser lithotripsy resulted in sufficient fragmentation in 7 patients. Bile duct clearance proved to be a particular problem with the percutaneous access. When a retrograde sphincterotomy is not possible an antegrade papillotomy must be attempted under fluoroscopic guidance. In bile duct strictures the implantation of expandable stents facilitates the passage of fragments and may prevent recurrent stricture and development of new stones.     

Holmium-YAG laser for gall stone fragmentation: an endoscopic tool.

A systematic review of the 2.1 mu holmium-YAG laser for gall stone lithotripsy was undertaken. This infrared laser, which can be used endoscopically and percutaneously, has safety advantages over other lasers and has potential as a general purpose vascular and surgical tool. Twenty nine gall stones (mean mass 1.3 g) were fragmented in vitro using pulse energies of 114 to 159 mJ/pulse at 5 Hz with a 0.6 mm fibre, while being held in an endoscopy basket. All stones were successfully fragmented, requiring an average of 566 pulses with a 5 Hz pulse repetition frequency. The number of pulses required increased with gall stone size and mass (p < 0.01), and decreased with both pulse energy (p < 0.01) and operator experience (p < 0.05). The biochemical content of the stone did not significantly affect the number of pulses needed. The potential hazard of the laser to the biliary endothelium was investigated. At the pulse energies used, five pulses at close contact penetrated into the serosa of fresh gall bladder wall. No damage was seen when two pulses were fired. This laser shows considerable promise in gall stone lithotripsy. Until further safety data are available, however, its use with endoscopic vision is advised.     

Endoscopic laser lithotripsy of large bile duct stones

Experimental work has established that the Candela (Candela Laser Corporation, Wayland, MA) flashlamp excited dye laser (wavelength, 504 nm) is a highly effective method for fragmenting biliary stones and has minimal potential for injuring the bile duct wall. This technique was evaluated in 25 complex patients whose stones, usually because of large size, did not respond to standard nonoperative treatment. The laser imaging was applied through a quartz fiber and aimed either under direct vision with choledochoscopes passed percutaneously or through a special "mother" duodenoscope or under fluoroscopic guidance at standard duodenoscopy. Laser treatment resulted in some fragmentation of stones in 23 cases. Subsequently, it proved that it was possible to clear the bile duct of stones in 20 patients, 12 of them receiving successful treatment during the same endoscopic procedure. There were no significant complications. This endoscopic technique seems to be a useful new alternative to surgery in patients with large and difficult bile duct stones.     

Use of pulsed energy delivery to minimize tissue injury resulting from carbon dioxide laser irradiation of cardiovascular tissues

The carbon dioxide (CO2) laser has been utilized for preliminary intraoperative cardiovascular applications, including coronary endarterectomy and ventricular endocardiectomy. CO2 lasers used for these applications have been operated in the continuous wave, chopped or pulsed mode at low peak powers. To evaluate the extent of boundary tissue injury, continuous, chopped and pulsed energy delivery of CO2 laser emission was used to bore through 192 5 mm thick myocardial slices in air. Continuous, chopped and pulsed delivery at a peak power of 500 W or less failed to eliminate light microscopic or ultrastructural signs of thermal injury. Only when a high energy CO2 laser (pulse energy 80 to 300 mJ, pulse duration 1 microseconds) was used at a peak power greater than 80 kW were all signs of thermal injury eliminated; furthermore, high peak power prevented thermal injury only when the beam was focused to achieve a peak power density greater than 60 kW/mm2. Under these conditions, pathologic findings were identical to those observed using excimer wavelengths. The results of these experiments indicate that: conventional CO2 lasers fail to minimize boundary tissue injury, elimination of thermal injury during intraoperative laser ablation requires that CO2 laser energy be focused to achieve a peak power density greater than 60 kW/mm2, and elimination of thermal injury can be achieved at a variety of wavelengths, provided that an appropriate energy profile is employed.     

中国胆道结石双频双脉冲激光碎石专家建议

胆道结石是消化系统常见疾病,目前主要治疗手段有外科手术、内镜下介入治疗等,但部分困难结石临床上仍面临挑战。双频双脉冲激光碎石术因其安全、高效等特点,是解决困难结石的有效方法。双频双脉冲掺钕钇铝石榴石激光是目前被国家药品监督管理局批准的可用于胆道结石碎石的激光技术,但其适应证、导入方式和操作规范等问题尚未形成共识。为此,国家消化系统疾病临床医学研究中心（上海）、中国医师协会内镜医师分会和中华医学会消化内镜学分会特邀国内消化、内镜与外科等相关领域专家,在参考国内外文献的基础上,经过充分讨论形成本专家建议,以期为国内规范开展胆道结石激光碎石提供指导和参考。     

Intracorporeal Shock Wave Lithotripsy (ISWL) in Bile Ducts under Peroral Endoscopy: Progress and Current Status

Attempting to use ISWL (intracorporeal shock wave lithotripsy) for treating large and difficult biliary stones was started in the mid 1970s, approximately 10 years before the introduction of ESWL (extracorporeal shock wave lithotripsy). However, in contrast to ESWL, ISWL did not quickly become popular in practise. The main reason for this delayed recognition, undoubtedly, lay in the technical difficulties of the peroral applications until the mid 1980s, when the development of an improved cholangios-cope system and a thin, flexible probe allowed the use of EHL (electrohydraulic lithotripsy) under direct vision during peroral cholangioscopy. Thanks to recent advances in technology, a powerful pulsed laser has begun to be used for ISWL through a 0.2 mm sized quartz fiber. A laser version of ISWL with such a thin probe is expected to facilitate its use by minimizing the endoscope system. The automatic stone-tissue recognition system which interrupts the laser discharge in case of wall contact is another useful advance in technology which increases the safety and therapeutic efficacy. Whereas laser techniques are still in development, ISWL with a laser will be the first choice technique for treating difficult bile duct stones after failure of mechanical lithotripsy and it also promises to improve its therapeutic efficacy for intrahepatic stones in combination with ESWL. In this article, the recent progresses and results of ISWL treatment were reviewed with a respect to the success of ESWL.     

多轴全方位机器人造影系统在内镜治疗胆道结石中的应用价值初探

目的探讨在行内镜逆行胰胆管造影（ERCP）时使用Artiszeego机器人对胆道进行3D旋转采集和三维重建的应用价值。方法对12例B超提示胆道扩张的病例,在行ERCP同时使用Artis zeego机器人进行3D旋转采集,并经工作站处理进行三维胆道重建,以内镜和手术取石结果为最终诊断,观察其对肝内外胆管结石诊断的符合率。结果12例患者均完成3D旋转采集和三维重建检查,其诊断结果与ERCP取石和手术取石结果均相符,诊断符合率100％,其中,ERCP诊断中2例肝外胆管结石数量不明,1例可疑结石及2例疑似肝内胆管结石病例均得到明确诊断。结论使用Artis zeego机器人对胆道进行3D旋转采集和三维重建有助于ERCP诊疗中对胆道病变做出精准判断。     

Laser lithotripsy of difficult bile duct stones under direct visual control.

Biliary laser lithotripsy was performed under direct visual control in 35 consecutive patients not amenable to routine endoscopy. The patients had 1-50 (median 1) bile duct stones with the greatest diameter of the largest stone being 9-42 mm (median 20 mm). Conventional endoscopic treatment had failed because of an inaccessible papilla (16 patients), biliary strictures (seven patients), and impaction or large size of calculi (12 patients). Twelve patients, depending on their anatomical condition, underwent peroral cholangioscopy by means of a mother-babyscope system. Percutaneous cholangioscopy was initially carried out in 23 patients, 7-20 days (median 10 days) after creation of a transhepatic fistula. Pulsed dye laser (32 patients) or alexandrite laser (three patients) lithotripsy was applied under an appropriate direct visual control in all cases. Complete stone disintegration succeeded in 33 of 35 patients. All resultant fragments passed the papilla within a mean number of 1.3 treatment sessions. Peroral cholangioscopic lithotripsy failed in two cases. One patient successfully underwent percutaneous laser treatment and the other patient was referred to surgery. Fever, temporary haemobilia, or a subcapsular liver haematoma were seen in a total of eight patients during establishment of the cutaneobiliary fistula. A 95 year old patient who had been admitted with septic cholangitis died because of cardiorespiratory failure 5 days after bile duct clearance. It is concluded that laser lithotripsy performed under a direct visual control is an effective and safe procedure for the non-surgical treatment of difficult bile duct stones. Ductal clearance can usually be achieved in a single treatment session when the papilla and the stones are accessible by the peroral route. Percutaneous cholangioscopic lithotripsy is more time consuming but highly effective even in patients with a difficult anatomy, bile duct strictures, or intrahepatic calculi. This approach should be limited, however, to cases not amenable to retrograde procedures because the creation of the cutaneobiliary fistula is not without risks.     

Plaque ablation by excimer laser irradiation using a movable energy-transmitting device

During the past 2 years, excimer laser energy has been shown to provide a highly suitable type of atherosclerotic plaque ablation, especially in small-diameter vessels such as coronary or crural arteries. Nevertheless, transmission of far-ultraviolet pulsed laser power has remained a major problem in animal studies and clinical trials. In an attempt to solve this problem, we constructed an energy-transmitting device for use with a Lambdaphysics EMG 102 excimer laser. The transmission system, which was housed in a rigid articulated arm, allowed movement in all directions and rotation along the long axis, thus permitting easy handling and guiding of the laser beam in the operating field. To test whether this device could deliver enough energy to remove atherosclerotic plaques within a period that would meet the requirements for intraoperative use, we obtained fresh human cadaver coronary arteries both with and without atherosclerotic disease, and irradiated them vertically and coaxially. A power meter was used to determine the effective amount of energy delivered at the distal end of each vessel. Energy densities up to 3 J/cm(2)/pulse were obtained, owing to energy focussing within the transmitting device. At 5 Hertz (Hz), tissue ablation consisted of approximately 20 microm/pulse. Areas of normal vascular tissue, as well as fibrohyalinous and lipid plaque components, were promptly ablated. Macroscopically, the "lasered holes" appeared well-circumscribed, with clear-cut surfaces and no carbonization. Light microscopy revealed no thermal damage to the boundary tissue. With this new energy-transmitting device, the surgeon can use excimer laser irradiation intraoperatively. There is no significant loss of energy between the generator and the tip, and energy densities of 3 J/cm(2)/pulse are available for sufficient plaque removal.     

How Should Biliary Stones be Managed?

Minimally invasive therapy is currently invaluable for the treatment of biliary stones. Clinicians should be familiar with the various endoscopic modalities that have been evolving. I reviewed the treatment of biliary stones from the common practice to pioneering procedures, and here I also briefly summarize the results of many related studies. Lithotripsy involves procedures that fragment large stones, and they can be roughly classified into two groups: intracorporeal modalities and extracorporeal shock-wave lithotripsy (ESWL). Intracorporeal modalities are further divided into mechanical lithotripsy (ML), electrohydraulic lithotripsy, and laser lithotripsy. ESWL can break stones by focusing high-pressure shock-wave energy at a designated target point. Balloon dilation after minimal endoscopic sphincterotomy (EST) is effective for retrieving large biliary stones without the use of ML. Peroral cholangioscopy provides direct visualization of the bile duct and permits diagnostic procedures or therapeutic interventions. Biliary stenting below an impacted stone is sometimes worth considering as an alternative treatment in elderly patients. This article focuses on specialized issues such as lithotripsy rather than simple EST with stone removal in order to provide important information on state-of-the-art procedures.     

Reduction of laser-induced pathologic tissue injury using pulsed energy delivery

Continuous-wave (CW) laser irradiation of cardiovascular tissues is characterized by 2 distinctive histologic findings: a superficial zone of coagulation necrosis and a subjacent zone of polymorphous lacunae. The present investigation was designed to determine whether such injury could be eliminated by altering the temporal profile of laser energy delivery. One hundred forty-five myocardial slices were irradiated with an air-tissue interface using CW laser irradiation at wavelengths of 488 to 515 nm (argon), 1,064 nm (Nd-YAG) and 10,600 nm (CO2). Pulsed laser irradiation included 248 nm (excimer); 355, 532 and 1,064 nm (Nd-YAG); and 515 nm (mode-locked argon). Energy profiles in the pulsed mode included a range of repetition rates (1 Hz to 256 MHz), pulse duration (0.2 to 358 ns) and pulse energies (2 nJ to 370 mJ). Resultant average powers were 0.1 to 38 W. Grossly visible charring of myocardial tissue was observed at all laser wavelengths when the laser energy profile was CW or pulsed at high repetition rates (more than 2 KHz) and low pulse energies (less than 3 mJ) independent of the wavelengths used. In contrast, when laser energy was pulsed at low repetition rates (less than 200 Hz) and large pulse energies (more than 10 mJ), neither gross nor histologic signs of thermal injury were observed. Pathologic injury associated with laser-induced tissue ablation may thus be substantially reduced by use of pulsed energy delivery at low repetition rates. Potential advantages of pulsed laser energy include a more benign healing process, a less thrombogenic surface, and improved preservation of structural tissue integrity.     

Percutaneous transhepatic cholangioscopy and lithotripsy in treating difficult biliary ductal stones: Two case reports

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP) is preferred for managing biliary obstruction in patients with bilio-enteric anastomotic strictures(BEAS) and calculi. In patients whose duodenal anatomy is altered following upper gastrointestinal(UGI) tract surgery, ERCP is technically challenging because the biliary tree becomes difficult to access by per-oral endoscopy.Advanced endoscopic therapies like balloon-enteroscopy or rendevous-ERCP may be considered but are not always feasible. Biliary sepsis and comorbidities may also make these patients poor candidates for surgical management of their biliary obstruction.CASE SUMMARY We present two 70-year-old caucasian patients admitted as emergencies with obstructive cholangitis. Both patients had BEAS associated with calculi that were predominantly extrahepatic in Patient 1 and intrahepatic in Patient 2. Both patients were unsuitable for conventional ERCP due to surgically-altered UGl anatomy. Emergency biliary drainage was by percutaneous transhepatic cholangiography(PTC) in both cases and after 6-weeks' maturation, PTC tracts were dilated to perform percutaneous transhepatic cholangioscopy and lithotripsy(PTCSL) for duct clearance. BEAS were firstly dilated fluoroscopically,and then biliary stones were flushed into the small bowel or basket-retrieved under visualization provided by the percutaneously-inserted video cholangioscope. Lithotripsy was used to fragment impacted calculi, also under visualization by video cholangioscopy. Satisfactory duct clearance was achieved in Patient 1 after one PTCSL procedure, but Patient 2 required a further procedure to clear persisting intrahepatic calculi. Ultimately both patients had successful stone clearance confirmed by check cholangiograms.CONCLUSION PTCSL offers a pragmatic, feasible and safe method for biliary tract clearance when neither ERCP nor surgical exploration is suitable.     

Laserlithotripsy of common bile duct stones.

Endoscopic retrograde laser lithotripsy of common bile duct stones is a new technique which can be carried out through the endoscope without anaesthesia using ordinary endoscopic equipment. In the method described here a flashlamp pulsed Neodymium YAG laser (wave length 1064 nm) was used. Light energy was transmitted along a highly flexible quartz fibre with a diameter of 0.2 mm. This new technique was used in nine patients with concrements in the common bile duct, which could not be removed with the established endoscopic techniques. In eight of the nine the concrements (maximum diameter 4.7 x 3.1 cm) could be fragmented and in six the fragments could be extracted from the common bile duct. The total energy required was 80-300 J; complications were not observed.     

Percutaneous pulsed laser-assisted balloon angioplasty guided by spectroscopy

Percutaneous laser angioplasty was performed in 19 patients with total superficial femoral calcified and noncalcified (4 to 25 cm length) occlusions; a pulsed dye laser of 480 nm was used with a pulse duration of 2 musec/pulse. The treatment laser was guided by a 325 nm diagnostic laser that induced fluorescence. The laser system operated through a single 200 or 500 microns optical fiber. Computerized spectral analysis of the tissue fluorescence located at the distal of the fiber tip allowed the treatment laser to be emitted on the atheroma and not on the arterial wall. Uniform success in primary laser recanalization was demonstrated, which allowed for subsequent balloon dilatation in all but one patient. One mechanical fiber perforation, two mechanical fiber dissections, one guidewire perforation, and one guidewire dissection occurred, but no complications resulting from the treatment or diagnostic laser were observed. The safety of the procedure appears to be enhanced by the spectroscopic guidance system, which allows recognition of plaque. The pulsed dye treatment laser was well tolerated and effective even in heavily calcified arteries.     

The Munich Gallbladder Lithotripsy Study. Results of the first 5 years with 711 patients

OBJECTIVE: To evaluate the long-term results of three types of shock wave treatment in patients with radiolucent gallbladder stones. DESIGN: Cohort study. SETTING: Single-center trial. PATIENTS: Of 5824 patients with gallstones, 19% were eligible; 711 patients were treated. INTERVENTIONS: Patients received extracorporeal shock wave lithotripsy as well as adjuvant therapy with bile acids. RESULTS: Lithotripsy was done in three ways, using a water-tank lithotriptor (group A), a water-cushion lithotriptor at low energy levels (group B), and a water-cushion lithotriptor at high energy levels (group C). The rate of complete fragment clearance 9 to 12 months after lithotripsy was done differed significantly among the three groups: Among patients with single stones of 20 mm or less in diameter, the rate of fragment clearance for group A was 76%; for group B, it was 60%; and for group C, it was 83% (P = 0.03). Among patients with single stones of 21 to 30 mm, the rate of fragment clearance for group A was 63%; for group B, it was 32%; and for group C, it was 58% (P less than 0.005). Among patients with two or three stones, the rate of fragment clearance for group A was 38%; for group B, it was 16%; and for group C, it was 46% (P = 0.01). Patients with fragments of 3 mm or less 24 hours after lithotripsy was done showed a higher probability of fragment disappearance than did those with larger fragments (P less than 0.001). The clearance rate was higher in patients who were compliant than in those who were noncompliant with bile acid therapy (P less than 0.001). Adverse effects included liver hematoma in 1 patients, biliary pain attacks in 253 patients (36%), mild biliary pancreatitis in 13 patients (2%), and cholestasis in 7 patients (1%). Elective cholecystectomy was done in 16 patients (2%), and endoscopic sphincterotomy was done in 4 patients (1%). CONCLUSIONS: The rate of complete disappearance of stones after shock wave therapy depends on the size and the number of the initial stones, the diameter of the largest fragment, and the mode of shock wave treatment. Adjuvant therapy with bile acids appears to be important for complete fragment clearance.     

Effect of preirradiation tissue target temperature upon selective vascular damage induced by 577-nm tunable dye laser pulses

The effect of hamster cheek pouch temperature upon the microvascular injury induced by pulsed laser dye radiation was studied. An appropriate wavelength (577 nm) and pulse width (300 nsec) were delivered by a flashlamp-pumped dye laser to induce selective vascular damage, as previously described. With increasing pulse energies, transient slowing of blood flow, stasis with brown discoloration of blood, and hemorrhage were observed. Cooling the cheek pouch to 8° before irradiation increased the laser exposure threshold for induction of such injury. Measurement of the exposure thresholds for hemorrhage at different temperatures suggests that microvessels are heated to between 90 and 100°, before hemorrhage occurs. These data are consistent with microvaporization as a major event in the sequence leading to hemorrhage, but do not exclude other possible mechanisms.     

Clinical usefulness of transpapillary removal of common bile duct stones by frequency doubled double pulse Nd：YAG laser

AIM： To study the efficacy and the safety of laser lithotripsy without direct visual control by using a balloon catheter in patients with bile duct stones that could not be extracted by standard technique.
METHODS： The seventeen patients （7 male and 10 female; mean age 67.8 years） with difficult common bile duct （CBD） stones were not amenable for conventional endoscopic maneuvers such as sphincterotomy and mechanical lithotripsy were included in this study. Laser wavelengths of 532 nm and 1064 nm as a double pulse were applied with pulse energy of 120 mJ. The laser fiber was advanced under fluoroscopic control through the ERCP balloon catheter. Laser lithotripsy was continued until the fragment size seemed to be less than 10 mm. Endoscopic extraction of the stones and fragments was performed with the use of the Dormia basket and balloon catheter.
RESULTS： Bile duct clearance was achieved in 15 of 17 patients （88%）. The mean number of treatment sessions was 1.7 ± 0.6. Endoscopic stone removal could not be achieved in 2 patients （7%）. Adverse effects were noted in three patients （hemobilia, pancreatitis, and cholangitis）.
CONCLUSION： The Frequency Doubled Double Pulse Nd：YAG （FREDDY） laser may be an effective and safe technique in treatment of difficult bile duct stones.     

Pulsed dye laser lithotripsy of bile duct stones.

Efficacy and safety of pulsed dye laser lithotripsy was tested in 25 consecutive patients in whom bile duct stones could not be extracted after endoscopic sphincterotomy. The patients had one to six (mean, 1.8) bile duct stones (diameter, 10-35 mm; mean, 18 mm) located in the common bile duct (18 cases), the intrahepatic bile ducts (6 cases), or in a long cystic duct stump (1 case). Different approaches were tested depending on the presence of a T tube and on the localization of the bile duct stones. When a T tube was present (7 cases), the lithotripsy was performed under direct vision using a choledochoscope inserted through the T-tube tract. In 18 patients without a T tube in place, the lithotripsy was performed under fluoroscopy using a retrograde approach in case of common bile duct stones (14 cases) or under choledochoscopy using a percutaneous transhepatic approach in case of intrahepatic bile duct stones (4 cases). Fragmentation of all the bile duct stones and a complete bile duct clearance were obtained in all 11 cases with procedures performed under direct vision as compared with only 5 of 14 cases with procedures under fluoroscopic control. Moreover, 6 of the 9 failures using the latter approach were offered another session using a choledochoscope inserted through a percutaneous transhepatic tract and were also successfully treated. No complication related to the laser beam was noted. It is concluded that pulsed dye laser lithotripsy of bile duct stones (that are unable to be removed by standard endoscopic techniques) is safe and efficacious provided that it is performed under direct vision. Technical refinements are needed before this procedure can be reliably performed under fluoroscopy.     

Electromagnetic shock-wave lithotripsy of gallbladder calculi. Multicentered preliminary report on experience with 276 patients

The Lithostar Working Group reports on the first 276 patients who underwent lithotripsy of biliary calculi by means of an electromagnetic Lithotriptor (Lithostar Plus from Siemens). Some 66% (183/276) and 27% (75/276) of the patients had solitary and two or three stones, respectively while 7% (18/276) had more than three gallbladder calculi. Calcified calculi were found in 11% of the patients. On an average the patients were treated in 1.6 (range 1.4-2.15) sessions; with the exception of one user the maximal energy (setting 9) was applied. The upper limit of shock waves per session was 1500-6000 (x = 2189 +/- 1058). 17% and 48% of the patients were free from calculi after 3 and 6 months, respectively. During the follow-up period 14% of the patients complained of severe biliary pain and 1.5% suffered from pancreatitis, which was controlled by conservative treatment. In three out of five patients with a transitory cholestatic jaundice endoscopic papillotomy was necessary. Four patients underwent an elective cholecystectomy. Considering the selection of the patients, the results obtained are comparable with those found in other studies.