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Joel M. H. Teichman - One of the best experts on this subject based on the ideXlab platform.
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Laser Lithotripsy Physics
Urinary Tract Stone Disease, 2010Co-Authors: Andrew J. Marks, Jinze Qiu, Thomas E. Milner, Kin F. Chan, Joel M. H. TeichmanAbstract:Lasers can be used as intracorporeal lithotriptors for urinary calculi. Laser Lithotripsy generally involves one of two mechanisms: photoacoustic or photothermal Lithotripsy. Photoacoustic Lithotripsy produces large fragments but has difficulty in fragmenting calcium oxalate monohydrate, cystine, and brushite stones. Photothermal Lithotripsy produces small fragments and is effective in fragmenting all stone compositions. Photothermal Lithotripsy, such was with the holmium:YAG laser, tends to be slow compared to photoacoustic Lithotripsy. The physics of photothermal Lithotripsy is reviewed with the objective to enhance fragmentation efficiency and minimization of retropulsion.
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Update On Erbium:YAG Lithotripsy
AIP Conference Proceedings, 2007Co-Authors: Joel M. H. Teichman, Hyun Wook Kang, Randolph D. Glickman, Ashley J. WelchAbstract:The Holmium:YAG laser fragments stones by a photothermal mechanism. It produces tiny fragments compared to short pulse duration lasers which fragment stones by laser induced shockwave Lithotripsy. Holmium:YAG Lithotripsy fragments stones of all compositions, but fragments stones slowly. In an effort to achieve photothermal Lithotripsy more efficiently, Erbium:YAG Lithotripsy has been tested. The Erbium:YAG laser fragments stones up to 5 times more efficiently than the Holmium:YAG laser. Its principal limitation is that it is not transmitted well by currently available fibers. Erbium:YAG Lithotripsy is more efficient than Holmium:YAG Lithotripsy but it is not yet practical for clinical use with current technology.
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Laser Lithotripsy.
Current Opinion in Urology, 2002Co-Authors: Joel M. H. TeichmanAbstract:All literature related to laser Lithotripsy published within the past year was reviewed. Salient articles have been reviewed and grouped according to safety issues, efficacy, comparison studies, biliary applications or future directions. There is no evidence of renal deterioration after holmium:yttrium-aluminium-garnet Lithotripsy. Laser-related complications occur in less than 1%. Stone-free rates from holmium:yttrium-aluminium-garnet Lithotripsy are greater than 90% for ureteral calculi, and 67-84% for renal calculi. This method of Lithotripsy is effective for ureteral and renal calculi in morbidly obese patients who are not suitable candidates for shock-wave Lithotripsy or percutaneous nephrolithotomy. Holmium:yttrium-aluminium-garnet Lithotripsy is more effective than pneumatic Lithotripsy for ureteral calculi, but no more effective than shock-wave Lithotripsy (Dornier HM-3) for distal ureteral calculi. Holmium:yttrium-aluminium-garnet Lithotripsy of biliary calculi is uniformly effective. Preliminary data showed the erbium:yttrium-aluminium-garnet laser to be more efficient than holmium:yttrium-aluminium-garnet energy, but current erbium:yttrium-aluminium-garnet fibers are impractical. The holmium:yttrium-aluminium-garnet laser is safe and effective. It is the lithotrite of choice for endoscopic ureteral and ureterorenoscopic Lithotripsy.
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In vitro erbium: YAG laser Lithotripsy
Laser-Tissue Interaction XI: Photochemical Photothermal and Photomechanical, 2000Co-Authors: Kin F. Chan, Joel M. H. Teichman, Randolph D. Glickman, Gracie Vargas, Patricia J. Parker, H. Stan Mcguff, Ashley J. WelchAbstract:The potential application of an Erbium:YAG (Er:YAG) laser (Q 0 = 50 mJ/pulse; τ p = 275 μs; rep. rate = 2, 10 Hz) with a sapphire delivery fiber for intracorporeal laser Lithotripsy was explored. Preliminary measurements on calculus mass-loss and fragmentation efficiency were conducted and results were compared with that of Ho:YAG laser Lithotripsy. Laser induced bubble and Lithotripsy dynamics were investigated to assess the mechanism(s) involved in the fragmentation process. Results showed that the fragmentation efficiency (mass-loss/H o - g.μm 2 /J) in Er:YAG laser Lithotripsy was about 2.4 times that of Ho:YAG laser Lithotripsy (used: Q 0 = 500 mJ/pulse; Tp = 250 μs; rep. rate = 10 Hz). Acoustic transients were found to have minimal effect during Er:YAG laser Lithotripsy. Schlieren flash images suggested a predominantly photothermal mechanism due to direct laser energy absorption, which resulted in recrystallization and plume formation. These events indicated melting and chemical decomposition of the calculus composition. Another observation led to the possibility of a plasma-mediated photothermal mechanism. The 'Moses effect' facilitating pulsed mid-infrared laser delivery appeared more efficient for the Er:YAG laser than for the Ho:YAG laser. With the sapphire fiber, experimental results suggested the potential of an improved treatment modality by the Er:YAG laser for intracorporeal laser Lithotripsy.
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Holmium:YAG Lithotripsy in children.
Journal of Urology, 1999Co-Authors: Tim Wollin, Joel M. H. Teichman, John D. Denstedt, Vince J. Rogenes, Hassan A. Razvi, Michael GrassoAbstract:Purpose: We determined the safety and efficacy of holmium:YAG Lithotripsy in children. Materials and Methods: We retrospectively reviewed the records of all holmium:YAG Lithotripsy done in patients 17 years old or younger. Demographic, preoperative, intraoperative and postoperative data were collected. Results: A total of 9 boys and 10 girls (26 stones) with a mean age of 11 years (range 1 to 17) were treated with holmium:YAG Lithotripsy, which was chosen as initial therapy in 10 (53%). Retrograde ureteroscopy was performed in 15 patients to treat 13 ureteral and 6 renal calculi, and percutaneous nephroLithotripsy was done in 4 to treat 3 ureteral and 4 renal calculi. A complete stone-free outcome after 1 procedure was achieved in 16 children (84%) and 3 patients were rendered stone-free after 2 procedures. No patient had an intraoperative injury. Followup ranged from 0.5 to 12 months (mean 3). Followup imaging has shown no evidence of stricture or hydronephrosis. Conclusions: Holmium:YAG Lithotripsy is safe and effective in children. It is a reasonable option for failed shock wave Lithotripsy, or in children with a known durile stone composition or contraindications to shock wave Lithotripsy.
Gary C. Bellman - One of the best experts on this subject based on the ideXlab platform.
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Original Articles HOLM1UM:YAG Lithotripsy YIELDS SMALLER FRAGMENTS THAN LITHOCLAST, PULSED DYE LASER OR ELECTROHYDRAULIC Lithotripsy
1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:Purpose: The mechanism of Lithotripsy Mers among eledrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size hm each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest fragments among these lithotrites. Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 pm. pulsed dye lasers and 365 Fm. ho1mium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition. Results: Ho1mium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no ho1mium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Ho1mium:YAG had significantly greater weight of fragments less than 1 mm. compared to the other lithotrites. Conclusions: Ho1mium:YAG yields smaller fragments compared to electrohydraulic Lithotripsy, mechanical Lithotripsy or pulsed dye lasers. These findings imply that fragments from ho1mium:YAG Lithotripsy are more likely to pass without problem compared to the other lithotrites. Furthermore, the significant difference in fragment size adds evidence that ho1mium:YAG Lithotripsy involves vaporization. The mechanisms of electrohydraulic Lithotripsy, mechanical Lithotripsy (lithoclast) and pulsed dye laser Lithotripsy are well understood.1-4 Electrohydraulic Lithotripsy creates an expanding cavitation bubble that collapses on itself, releasing an acoustic pressure wave or shock wave. Mechanical Lithotripsy (Lithoclast) fragments calculi by a mechanism akin to a pneumatic jackhammer. Pulsed dye lasers energy vaporizes the medium creating an expanding cavitation bubble that leads to an acoustic pressure wave. The process of creating a vapor plasma requires specific conditions necessary to achieve laser induced shock wave Lithotripsy. In contast, the mechanism of ho1mium:YAG Lithotripsy is not well understood but it is believed to involve direct stone absorption of laser energy and not to involve laser induced shock wave Jithotripsy.4 Because the Lithotripsy mechanisms of electrohydraulic lithotripey, mechanical Lithotripsy, pulsed dye lasers, and ho1mium:YAG Lithotripsy differ, we postulated that the fragment size might also differ. Clinically, ho1mium:YAG Lithotripsy sgems to create minute fragments, a result that appears different endoscopically compared to the other
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holmium yag Lithotripsy yields smaller fragments than lithoclast pulsed dye laser or electrohydraulic Lithotripsy
The Journal of Urology, 1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:AbstractPurpose: The mechanism of Lithotripsy differs among electrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size from each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest among the lithotrites.Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 micro m. pulsed dye lasers and 365 micro m. holmium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition.Results: Holmium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no holmium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Holmiu...
John D. Denstedt - One of the best experts on this subject based on the ideXlab platform.
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lower pole i a prospective randomized trial of extracorporeal shock wave Lithotripsy and percutaneous nephrostolithotomy for lower pole nephrolithiasis initial results
The Journal of Urology, 2001Co-Authors: David M Albala, Ralph V. Clayman, John D. Denstedt, James E. Lingeman, Michael Grasso, Dean G Assimos, Jorge Gutierrezaceves, Robert I Kahn, Raymond J Leveillee, N Joseph J R MacalusoAbstract:Purpose: The efficacy of shock wave Lithotripsy and percutaneous stone removal for the treatment of symptomatic lower pole renal calculi was determined.Materials and Methods: A prospective randomized, multicenter clinical trial was performed comparing shock wave Lithotripsy and percutaneous stone removal for symptomatic lower pole only renal calculi 30 mm. or less.Results: Of 128 patients enrolled in the study 60 with a mean stone size of 14.43 mm. were randomized to percutaneous stone removal (58 treated, 2 awaiting treatment) and 68 with a mean stone size of 14.03 mm. were randomized to shock wave Lithotripsy (64 treated, 4 awaiting treatment). Followup at 3 months was available for 88% of treated patients. The 3-month postoperative stone-free rates overall were 95% for percutaneous removal versus 37% Lithotripsy (p <0.001). Shock wave Lithotripsy results varied inversely with stone burden while percutaneous stone-free rates were independent of stone burden. Stone clearance from the lower pole following...
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Holmium:YAG Lithotripsy in children.
Journal of Urology, 1999Co-Authors: Tim Wollin, Joel M. H. Teichman, John D. Denstedt, Vince J. Rogenes, Hassan A. Razvi, Michael GrassoAbstract:Purpose: We determined the safety and efficacy of holmium:YAG Lithotripsy in children. Materials and Methods: We retrospectively reviewed the records of all holmium:YAG Lithotripsy done in patients 17 years old or younger. Demographic, preoperative, intraoperative and postoperative data were collected. Results: A total of 9 boys and 10 girls (26 stones) with a mean age of 11 years (range 1 to 17) were treated with holmium:YAG Lithotripsy, which was chosen as initial therapy in 10 (53%). Retrograde ureteroscopy was performed in 15 patients to treat 13 ureteral and 6 renal calculi, and percutaneous nephroLithotripsy was done in 4 to treat 3 ureteral and 4 renal calculi. A complete stone-free outcome after 1 procedure was achieved in 16 children (84%) and 3 patients were rendered stone-free after 2 procedures. No patient had an intraoperative injury. Followup ranged from 0.5 to 12 months (mean 3). Followup imaging has shown no evidence of stricture or hydronephrosis. Conclusions: Holmium:YAG Lithotripsy is safe and effective in children. It is a reasonable option for failed shock wave Lithotripsy, or in children with a known durile stone composition or contraindications to shock wave Lithotripsy.
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Management of Vesical Calculi: Comparison of Lithotripsy Devices
Journal of Endourology, 1996Co-Authors: Hassan Razvi, John D. DenstedtAbstract:Although endoscopic Lithotripsy of bladder stones has been well described and is widely practiced, comparison of the main modalities of mechanical, electrohydraulic, and ultrasonic Lithotripsy is lacking. The exact role of these and other modalities such as the Swiss Lithoclast and extracorporeal Shockwave Lithotripsy is not clearly defined. The safety and efficacy of the various Lithotripsy modalities available to treat bladder calculi were reviewed retrospectively over an 18-year period. A total of 106 patients were treated with some form of intracorporeal Lithotripsy. In general, all devices proved to be effective with a low rate of complications. The addition of transurethral resection of the prostate to bladder stone management under the same anesthetic was also found to be a safe procedure for moderate benign prostatic hyperplasia. In summary, transurethral endoscopic Lithotripsy is a safe and effective method of bladder stone management both alone and in combination with transurethral prostatectomy...
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Electrohydraulic Lithotripsy of Renal and Ureteral Calculi
Journal of Urology, 1990Co-Authors: John D. Denstedt, Ralph V. ClaymanAbstract:AbstractElectrohydraulic Lithotripsy was used to manage 45 upper tract calculi (23 renal and 22 ureteral stones) in 40 patients. Electrohydraulic Lithotripsy successfully fragmented 91% of the calculi. All ureteral fragments cleared; in 2 patients with renal calculi solitary 4mm. stone fragments remained. There were no intraoperative or long-term complications directly related to the use of electrohydraulic Lithotripsy in the upper urinary tract. We conclude that intrarenal and intraureteral electrohydraulic Lithotripsy is a safe, effective, inexpensive means to perform intracorporeal Lithotripsy. (J. Urol, 143: 13–17, 1990)
George J. Vassar - One of the best experts on this subject based on the ideXlab platform.
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Original Articles HOLM1UM:YAG Lithotripsy YIELDS SMALLER FRAGMENTS THAN LITHOCLAST, PULSED DYE LASER OR ELECTROHYDRAULIC Lithotripsy
1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:Purpose: The mechanism of Lithotripsy Mers among eledrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size hm each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest fragments among these lithotrites. Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 pm. pulsed dye lasers and 365 Fm. ho1mium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition. Results: Ho1mium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no ho1mium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Ho1mium:YAG had significantly greater weight of fragments less than 1 mm. compared to the other lithotrites. Conclusions: Ho1mium:YAG yields smaller fragments compared to electrohydraulic Lithotripsy, mechanical Lithotripsy or pulsed dye lasers. These findings imply that fragments from ho1mium:YAG Lithotripsy are more likely to pass without problem compared to the other lithotrites. Furthermore, the significant difference in fragment size adds evidence that ho1mium:YAG Lithotripsy involves vaporization. The mechanisms of electrohydraulic Lithotripsy, mechanical Lithotripsy (lithoclast) and pulsed dye laser Lithotripsy are well understood.1-4 Electrohydraulic Lithotripsy creates an expanding cavitation bubble that collapses on itself, releasing an acoustic pressure wave or shock wave. Mechanical Lithotripsy (Lithoclast) fragments calculi by a mechanism akin to a pneumatic jackhammer. Pulsed dye lasers energy vaporizes the medium creating an expanding cavitation bubble that leads to an acoustic pressure wave. The process of creating a vapor plasma requires specific conditions necessary to achieve laser induced shock wave Lithotripsy. In contast, the mechanism of ho1mium:YAG Lithotripsy is not well understood but it is believed to involve direct stone absorption of laser energy and not to involve laser induced shock wave Jithotripsy.4 Because the Lithotripsy mechanisms of electrohydraulic lithotripey, mechanical Lithotripsy, pulsed dye lasers, and ho1mium:YAG Lithotripsy differ, we postulated that the fragment size might also differ. Clinically, ho1mium:YAG Lithotripsy sgems to create minute fragments, a result that appears different endoscopically compared to the other
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holmium yag Lithotripsy yields smaller fragments than lithoclast pulsed dye laser or electrohydraulic Lithotripsy
The Journal of Urology, 1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:AbstractPurpose: The mechanism of Lithotripsy differs among electrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size from each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest among the lithotrites.Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 micro m. pulsed dye lasers and 365 micro m. holmium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition.Results: Holmium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no holmium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Holmiu...
Jay T. Bishoff - One of the best experts on this subject based on the ideXlab platform.
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Original Articles HOLM1UM:YAG Lithotripsy YIELDS SMALLER FRAGMENTS THAN LITHOCLAST, PULSED DYE LASER OR ELECTROHYDRAULIC Lithotripsy
1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:Purpose: The mechanism of Lithotripsy Mers among eledrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size hm each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest fragments among these lithotrites. Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 pm. pulsed dye lasers and 365 Fm. ho1mium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition. Results: Ho1mium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no ho1mium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Ho1mium:YAG had significantly greater weight of fragments less than 1 mm. compared to the other lithotrites. Conclusions: Ho1mium:YAG yields smaller fragments compared to electrohydraulic Lithotripsy, mechanical Lithotripsy or pulsed dye lasers. These findings imply that fragments from ho1mium:YAG Lithotripsy are more likely to pass without problem compared to the other lithotrites. Furthermore, the significant difference in fragment size adds evidence that ho1mium:YAG Lithotripsy involves vaporization. The mechanisms of electrohydraulic Lithotripsy, mechanical Lithotripsy (lithoclast) and pulsed dye laser Lithotripsy are well understood.1-4 Electrohydraulic Lithotripsy creates an expanding cavitation bubble that collapses on itself, releasing an acoustic pressure wave or shock wave. Mechanical Lithotripsy (Lithoclast) fragments calculi by a mechanism akin to a pneumatic jackhammer. Pulsed dye lasers energy vaporizes the medium creating an expanding cavitation bubble that leads to an acoustic pressure wave. The process of creating a vapor plasma requires specific conditions necessary to achieve laser induced shock wave Lithotripsy. In contast, the mechanism of ho1mium:YAG Lithotripsy is not well understood but it is believed to involve direct stone absorption of laser energy and not to involve laser induced shock wave Jithotripsy.4 Because the Lithotripsy mechanisms of electrohydraulic lithotripey, mechanical Lithotripsy, pulsed dye lasers, and ho1mium:YAG Lithotripsy differ, we postulated that the fragment size might also differ. Clinically, ho1mium:YAG Lithotripsy sgems to create minute fragments, a result that appears different endoscopically compared to the other
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holmium yag Lithotripsy yields smaller fragments than lithoclast pulsed dye laser or electrohydraulic Lithotripsy
The Journal of Urology, 1998Co-Authors: Joel M. H. Teichman, George J. Vassar, Jay T. Bishoff, Gary C. BellmanAbstract:AbstractPurpose: The mechanism of Lithotripsy differs among electrohydraulic Lithotripsy, mechanical Lithotripsy, pulsed dye lasers and holmium:YAG Lithotripsy. It is postulated that fragment size from each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG Lithotripsy yields the smallest among the lithotrites.Materials and Methods: We tested 3F electrohydraulic Lithotripsy, 2 mm. mechanical Lithotripsy, 320 micro m. pulsed dye lasers and 365 micro m. holmium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition.Results: Holmium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no holmium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Holmiu...
