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At least 109 records · Page 6Linked to original sources
PubMed1997

Fluoroscopically guided laser lithotripsy versus extracorporeal shock wave lithotripsy for retained bile duct stones: a prospective randomised study.

BACKGROUND AND AIMS: To compare extracorporeal shock wave lithotripsy (ESWL) and laser induced shock wave lithotripsy (LISL) of retained bile duct stones to stone free rate, number of therapeutic sessions, and costs. PATIENTS: Thirty four patients were randomly assigned to either ESWL or LISL therapy. The main reasons for failure of standard endoscopy were due to stone impaction (n = 12), biliary stricture (n = 8), or large stone diameter (n = 14). METHODS: An extracorporeal piezoelectic lithotripter with ultrasonic guidance and a rhodamine 6G laser with an integrated stone tissue detection system were used. LISL was performed exclusively under radiological control. RESULTS: Using the initial methods complete stone fragmentation was achieved in nine of 17 patients (52.4%) of the ESWL group and in 14 of 17 patients (82.4%) in the LISL group, or combined with additional fragmentation techniques 31 of the 34 patients (91.2%) were stone free at the end of treatment. In comparison LISL tended to be more efficient in clearing the bile ducts (p = 0.07, NS). Significantly less fragmentation sessions (1.29 v 2.82; p = 0.0001) and less additional endoscopic sessions (0.65 v 1.6; p = 0.002) were necessary in the LISL group. There were no major complications in either procedure. CONCLUSIONS: Compared with ESWL, fluoroscopically guided LISL achieves stone disintegration more rapidly and with significantly less treatment sessions, which leads to a significant reduction in cost.

Adult↗
PubMed1988

Effects of pulsed dye laser lithotripsy on tissues. Experimental study in the canine ureter.

This experimental study demonstrates the absence of irreversible tissue damage after lithotripsy with a pulsed dye laser. The absence of thermal damage with this laser is due to the beam divergence capacity at the end of the fiber and to the short pulse, which generates very low thermal effect. These results as a whole confirm the safety of the pulsed dye laser and indicate that it can be used for clinical treatments in humans.

Animals↗
PubMed1998

Pulsed dye laser lithotripsy for treatment of urolithiasis in two geldings.

Transendoscopic pulsed dye laser lithotripsy was effective in the treatment of calcium carbonate urothlithiasis in 2 adult geldings. Perineal urethrotomy provided convenient access for standing transendoscopic lithotripsy and evacuation of a large cystic calculus in one gelding. In the second horse, an obstructive urethral calculus was fragmented and removed by a transurethroscopic approach. Pulsed dye laser lithotriptor is effective in fragmentation of the most common form (calcium carbonate) of uroliths in horses and may be performed in standing horses with reduced surgical invasiveness and trauma to the urinary tract, compared with conventional approaches. The principle disadvantages include cost of the procedure, which is comparable to laparocystotomy, and the time delay required to make arrangements for use of the pulsed dye laser lithotriptor.

Animals↗
PubMed1990

Laser lithotripsy of ureteral calculi: initial experience with a new pulsed dye laser.

Thirty-two patients with ureteral calculi ranging in size from 5 x 5 to 12 x 18 mm underwent lithotripsy with a new pulsed dye laser (Pulsolith, TMI). In 24 cases, the patients were entirely free of stones following laser lithotripsy alone, or with adjunctive stone basket removal. There were three instances of equipment failure and five calcium oxalate monohydrate stones that did not respond to laser energy.

Calcium Oxalate↗
PubMed1992

Laser lithotripsy of the difficult ureteral calculus: results in 122 patients.

We studied 122 patients with ureteral calculi who could not be treated by extracorporeal shock wave lithotripsy (ESWL) because the stones could not be localized or focused for treatment, the patient had failed prior ESWL, the stones were impacted and in situ ESWL was likely to fail or the stones were proximal to a ureteral stricture. These patients underwent laser lithotripsy using the Candela pulsed dye laser. In 107 patients (88%) the calculi were completely fragmented with the laser alone, while 10 (8%) needed another procedure (ESWL in 8 and stone fragment extraction by basket in 2), and 5 (4%) had failed laser therapy and needed some other form of treatment (ESWL in 4 and percutaneous antegrade extraction in 1). At 3 months 116 of 122 patients (95%) were stone-free. There were 2 immediate complications (ureteral perforations) and 1 late complication (ureteral stricture). Laser lithotripsy is a safe and effective method of intracorporeal fragmentation, even of the difficult ureteral calculus, and it is a useful adjunct to ESWL.

Adolescent↗
PubMed1996

Complex biliary stones: treatment with a small choledochoscope and laser lithotripsy.

PURPOSE: To evaluate the use of a small choledochoscope and laser lithotripsy in the treatment of complex biliary stone disease. MATERIALS AND METHODS: Twenty-five consecutive patients with complex biliary stone disease not amenable to surgical therapy, peroral endoscopic removal, or simple percutaneous retrieval techniques underwent 35 stone-removal procedures. A 3.4-mm endoscope and a pulsed dye coumarin green laser were used to pulverize and remove stones through preexisting, mature transhepatic biliary drain tracts (n = 18), t-tube tracts (n = 3), cholecystostomy tube tracts (n = 3), and a hepaticocutaneous enterostomy (n = 1). Procedures in 14 of the 25 patients (56%) were performed on an outpatient basis. RESULTS: Twenty-four of the 25 patients (96%) were cleared of their stone burden and underwent subsequent catheter therapy of strictures or abscesses as necessary. Complications of the stone removal included fever and chills in six patients (24%) and mild bleeding from a bile duct wall during removal of an adherent stone in one patient. CONCLUSION: Use of a small choledochoscope and a coumarin green pulsed dye laser is safe and effective in the management of complex biliary stone disease.

Bile Duct Diseases↗
PubMed2003

Upper tract imaging after ureteroscopic holmium:YAG laser lithotripsy: when is it necessary?

INTRODUCTION/OBJECTIVE: Advances in ureteroscope design and refinements of ancillary instrumentation have resulted in an expanded role for ureteroscopy in the management of urinary calculi. Technological enhancements coupled with improved endourologic skills have also been associated with a reduction in procedural-related complications. Historically, postoperative imaging with ultrasound (U/S) or intravenous pyelogram (IVP) had been advocated to rule out persistent obstruction due to retained stone fragments or ureteral stricture. The purposes of this study were to evaluate the incidence of postoperative ureteral obstruction in a contemporary series of patients undergoing ureteroscopic holmium:YAG laser lithotripsy without basket extraction of fragments and to identify patient, stone and operative factors predictive of which patients will benefit from postoperative imaging. MATERIALS AND METHODS: The charts and imaging studies of 89 consecutive patients undergoing a total of 94 holmium:YAG ureteroscopic lithotripsy procedures between December 1998 and December 2000 were retrospectively reviewed. Preoperative, intraoperative and postoperative data were collected and analyzed. The primary outcome measure was the incidence of postoperative ureteral obstruction documented on upper tract imaging. Secondary outcome measures included interventions required for postoperative obstruction and other nonobstructive postoperative complications. RESULTS: Twenty-eight females and 61 males were studied, with a mean patient age of 54 (range 13-80) years. Fifty-five percent of patients underwent related procedures prior to referral to our tertiary endourology centre. Complete clinical and radiological follow-up is available for 68 of 89 (76.4%) patients, with a mean follow-up duration of 24.2 weeks. Overall stone-free rate was 97%. Six patients had evidence of urinary tract obstruction on follow-up radiological assessment, two from residual stone fragments and four from ureteral stricture. Each of these four patients had at least one preoperative risk factor for ureteral stricture. CONCLUSIONS: Routine postoperative upper tract imaging is not necessary in all patients undergoing uncomplicated ureteroscopic holmium:YAG laser lithotripsy. Indications for upper tract imaging include chronic stone impaction, significant ureteral trauma, pre-existing renal function impairment, endoscopic evidence of stricture and postoperative flank pain or fever.

Adolescent↗
PubMed1990

Laser lithotripsy. The new stone age.

1. Advancements in stone management focus on the ability to safely fragment urinary calculi into small pieces, permitting simple elimination or facilitating retrieval and extraction. 2. The coumarin pulsed dye laser offers a safe and minimally invasive alternative in the treatment of calculi not amenable to or safely treated by other fragmentation techniques. 3. No complications have been directly attributed to laser lithotripsy. 4. Understanding laser mechanics and the principles of laser photo-fragmentation will promote the safe and knowledgeable integration of this revolutionary technology into the perioperative care of patients with urolithiasis.

Humans↗
PubMed1992

Laser lithotripsy for the management of retained stones.

The morbidity of reoperation for retained biliary stones is not significant. Many techniques have been developed to avoid reoperation. This study analyzes T-tube tract choledochoscopy and lithotripsy using a 504-nm pulsed dye laser for treatment of retained stones. A flexible choledochoscope is passed into the biliary tract and laser energy is delivered under endoscopic visualization after passing a 320-microns laser fiber through the instrument channel. Eight patients were treated in nine sessions. The mean number of pulses was 1512.33, delivered at 3 to 5 Hz with an energy of 100 to 120 mJ. In all patients, the biliary tract was cleared. A single patient's treatment was complicated by transient bacteremia. Mean follow-up was 10 months. Choledochoscopic laser lithotripsy is a safe, effective technique that may also play a major role in laparoscopic common duct surgery.

Boston↗
PubMed1995

Laser lithotripsy for ureteric calculi: results in 250 patients.

Two hundred and fifty patients with 290 stones presenting to the Department of Urology were treated with the Candela MDL 2000 Laser Lithotripter. Overall stone clearance rate was 95%. The more proximal the calculus the lower the success rate. Ninety eight percent of stones in the lower ureter, 95% of mid ureteric and 91% of upper ureteric stones were cleared. The major complication was perforation which occurred in 6% of cases. This procedure is a safe and effective treatment for ureteric calculi and is associated with a low complication rate and a high clearance rate. Laser lithotripsy is the optimum ureteroscopic method of treating ureteric calculi and is complimentary to extra corporeal shock wave lithotripsy.

Adolescent↗
PubMed1994

[Laser lithotripsy of ureteral calculi].

A total of 149 patients with 152 ureteral stones were treated with intraureteral lithotripsy by Dye-laser (83.55%), Alexandrite-laser (41.27%), electrohydraulic lithotripsy adapted for use in the ureter (25.16%) or neodymium: YAG laser with optomechanic coupling (3.2%). The Dye-laser has an automatic pulse shut-off mechanism with spectral analysis of the reflected laser beam, so that effective laser pulses can only be released by contact with a stone. Most (127 of 83.5%) of the stones could be completely fragmented, so that no further treatment was necessary. In 16 cases (10.5%) the stone was too hard for fragmentation and had to be removed by alternative techniques. Intraureteral lithotripsy is a save and effective method of treating ureteral stones that cannot be reached or have not been treated successfully by shockwave lithotripsy. No significant differences in outcome were found between the different lasers or electrohydraulic lithotripsy. In selected cases endoscopic treatment may be recommended as treatment of first choice.

Adolescent↗
PubMedDate not supplied

Laser lithotripsy for treatment of canine uroliths.

OBJECTIVE: To confirm in vivo optimal laser energy settings previously determined in vitro for lithotripsy, to develop a technique for Ho:YAG laser lithotripsy, and to evaluate acute and chronic tissue effects of laser lithotripsy. STUDY DESIGN: Prospective, randomized preclinical trial. ANIMALS OR SAMPLE POPULATION: Nineteen intact, adult male dogs. METHODS: Via cystotomy, a single urolith was inserted into the urethra to the level of the base of the os penis to simulate obstruction. Uroliths (calcium oxalate, urate, or magnesium ammonium phosphate) were fragmented by Ho:YAG laser, in contact mode through a 320 micro optic fiber, passed through the operating channel of a 2.8 mm flexible endoscope. The time and total energy to fragmentation were recorded. Dogs were euthanatized immediately after lithotripsy (3 dogs) or at 3 days (7 dogs), and urethral lesions and any stone remnants were evaluated. Urethral integrity was also evaluated in 9 other dogs by endoscopy on day 10; these were also monitored clinically for 30 days. RESULTS: The mean time for adequate fragmentation was 166.7 seconds (range, 47-494.5 seconds). The mean+/-SD energy used was 1418+/-851.2 J. In part 1, 2 dogs were obstructed with urolith fragments at necropsy. Eight dogs had minimal (<30 mg) or no urolith material evident within the urethra. Four dogs had gross focal or circumferential erosion, ulceration, or hemorrhage of the urethral mucosa. Lesions were not associated with the site of laser irradiation in 2 dogs. In dogs observed for 30 days, hematuria, pollakiuria, and stranguria that were observed after lithotripsy, resolved in all affected dogs by day 5. No mucosal lesions were observed by endoscopy and none of the dogs became obstructed. CONCLUSION: Laser lithotripsy with the Ho:YAG laser in contact mode successfully fragmented obstructive uroliths in male dogs. CLINICAL RELEVANCE: Laser lithotripsy may be a clinically relevant technique for treatment of urolithiasis in male dogs; clinical studies to evaluate long-term effects on urethral mucosa and the role of repeat treatment for recurrence are indicated.

Animals↗
PubMed2002

Erbium: YAG laser lithotripsy mechanism.

PURPOSE: We tested the hypothesis that the mechanism of long pulse erbium:YAG laser lithotripsy is photothermal. MATERIALS AND METHODS: Human urinary calculi were placed in deionized water and irradiated with erbium:YAG laser energy delivered through a sapphire optical fiber. Erbium:YAG bubble dynamics were visualized with Schlieren flash photography and correlated to acoustic emissions measured by a polyvinylidene fluoride needle hydrophone. The sapphire fiber was placed either parallel or perpendicular to the calculus surface to assess the contribution of acoustic transients to fragmentation. Stones were irradiated using desiccated stone irradiated in air, hydrated stone irradiated in air and hydrated stone irradiated in water. Ablation crater sizes were compared. Uric acid stones were irradiated in water and the water was assayed for cyanide. RESULTS: During the early phase of vapor bubble expansion, acoustic transients had minimal effects on calculus fragmentation. Fragmentation occurred due to direct absorption of laser energy transmitted to the calculus through the vapor channel between the sapphire fiber tip and calculus. The forward axial expansion of the bubble occurred more rapidly than the radial expansion. A parallel oriented fiber on the calculus surface produced no fragmentation but generated larger amplitude acoustic transients compared to perpendicular orientation. In perpendicular orientation the erbium:YAG laser did not generate any collapse acoustic waves but fragmentation occurred. Crater width was greatest for desiccated stones irradiated in air (p <0.03). Cyanide production increased as erbium:YAG irradiation of uric acid calculi increased, (r2 = 0.98). CONCLUSIONS: The erbium:YAG laser fragments stones through a photothermal mechanism.

Humans↗
PubMed1997

Nonlinear absorption: intraocular microsurgery and laser lithotripsy.

The paper reviews the principles of nonlinear absorption with reference to the present major clinical applications of plasma-mediated effects: intraocular microsurgery and laser lithotripsy. Emphasis is laid on the analysis of the working mechanisms, sources of collateral damage, and on strategies for both the optimization of efficacy and the minimization of side effects.

Absorption↗
PubMed2006

Ureteroscopy and holmium laser lithotripsy in pregnancy: stents must be used postoperatively.

PURPOSE: To present our experience with ureteroscopy and holmium laser lithotripsy in pregnant patients and discuss the need for stents postoperatively. PATIENTS AND METHODS: A retrospective analysis was performed on seven consecutive pregnant patients presenting with renal colic necessitating intervention between 1997 and 2003. One patient presented during the first, five in the second, and one in the third trimester. Abdominal ultrasonography was the primary diagnostic test. If the stone could not be seen with a rigid ureteroscope, flexible ureteroscopy (f-URS) was performed. Stones were fragmented with a holmium laser, and large fragments were taken out. Ureteral stents were placed routinely in all but the first two patients. RESULTS: The ureteral stones could be seen with ultrasonography in three patients. In four patients, holmium lasertripsy could be done by the rigid ureteroscope. In the remaining patients, f-URS was performed, and two upper-system stones were fragmented. Six patients were rendered stone free. In one patient, both collectingsystem dilation and right perirenal liquid accumulation were present by ultrasonography, but no stones could be detected. Ureteral-stent insertion reduced postoperative pain and analgesic use in the whole group. CONCLUSIONS: When conservative therapy fails in the pregnant patient with a ureteral stone, ureteroscopy and holmium lasertripsy should be considered. Routine insertion of ureteral stents with pull-out strings for at least 72 hours will reduce the pain and analgesic use postoperatively.

Adult↗