Dornier HM3 Lithotripter Research Articles

Shock Wave Lithotripsy in Pediatric Stone Disease: A 15-Year Single-Center Experience with 2 Types of Lithotripters

Introduction and Objectives: We report our experience with pediatric shock wave lithotripsy (SWL) using two types of lithotripters: Dornier HM3 (HM3) and Dornier Lithotripter SII (DLS). Study Design: We retrospectively reviewed the charts of children who underwent SWL between 2002 and 2016. Patients were divided into two groups based on the type of the lithotripter: during 2002–2009, we used the electrohydraulic HM3 lithotripter which was replaced in 2009 with the DLS electromagnetic lithotripter. Clinical and perioperative parameters were compared. Results: Our cohort included 107 children who underwent SWL. Average age was 11.5 ± 5.1 years. Average stone size was 10.6 ± 4.9 mm. HM3 was used in 38% of children and DLS2 in 62% (n = 41 and 66, respectively). There were no significant differences in age, gender, stone size, or location between the groups. The total SFR did not differ statistically between HM3 and DLS (83% vs. 74%, p = 0.35). SFR after one SWL was higher with the HM3 (78% vs. 62%, p = 0.093). Re-treatment rate was 22% and 17% (HM3 vs. DLS, p = 0.61). Complication rates were low, with renal colic being the most common (HM3 10%, DLS 20%, NS). Conclusions: SWL in the pediatric population using the DLS showed good results with low complication rates that are equivalent to the gold standard HM3.

Biliary lithotripsy and what we learned from Carstensen

In the early 1990s, kidney-stone lithotripsy was a new burgeoning field and applications to gallstone destruction were being investigated. I came as the 1989-90 Hunt Fellow to work on the mechanisms of lithotripsy and related areas with Edwin Carstensen and his collaborators at the University of Rochester. The composition and liquid environment of gallstones is very different from that of kidney stones, however, and successful fragmentation of gallstones was rare. Comparing a Diasonics piezoelectric lithotripter and Dornier HM-3 lithotripter provided insights, as did studies of the mechanical and acoustical properties of gallstones. More generally, biliary lithotripsy led to fundamental studies of mechanisms of fragmentation and the interaction of acoustic shock waves outside and inside stones. While eventually the success of laproscopic surgery spelled the end of biliary lithotripsy as a competing technology, Ed Carstensen and his collaborators added knowledge that later paid dividends in related fields of biomedical acoustics, such as atherosclerotic plaque removal, sonothrombolysis, and cavitation-based imaging and therapy.

Using 300 Pretreatment Shock Waves in a Voltage Ramping Protocol Can Significantly Reduce Tissue Injury During Extracorporeal Shock Wave Lithotripsy

Pretreating a pig kidney with 500 low-energy shock waves (SWs) before delivering a clinical dose of SWs (2000 SWs, 24 kV, 120 SWs/min) has been shown to significantly reduce the size of the hemorrhagic lesion produced in that treated kidney, compared with a protocol without pretreatment. However, since the time available for patient care is limited, we wanted to determine if fewer pretreatment SWs could be used in this protocol. As such, we tested if pretreating with 300 SWs can initiate the same reduction in renal lesion size as has been observed with 500 SWs. Fifteen female farm pigs were placed in an unmodified Dornier HM-3 lithotripter, where the left kidney of each animal was targeted for lithotripsy treatment. The kidneys received 300 SWs at 12 kV (120 SWs/min) followed immediately by 2000 SWs at 24 kV (120 SWs/min) focused on the lower pole. These kidneys were compared with kidneys given a clinical dose of SWs with 500 SW pretreatment, and without pretreatment. Renal function was measured both before and after SW exposure, and lesion size analysis was performed to assess the volume of hemorrhagic tissue injury (% functional renal volume, FRV) created by the 300 SW pretreatment regimen. Glomerular filtration rate fell significantly in the 300 SW pretreatment group by 1 hour after lithotripsy treatment. For most animals, low-energy pretreatment with 300 SWs significantly reduced the size of the hemorrhagic injury (to 0.8% ± 0.4%FRV) compared with the injury produced by a typical clinical dose of SWs. The results suggest that 300 pretreatment SWs in a voltage ramping treatment regimen can initiate a protective response in the majority of treated kidneys and significantly reduce tissue injury in our model of lithotripsy injury.

Editorial Comment

The authors1 performed a meta-analysis comparing outcomes of shock wave lithotripsy and ureteroscopic lithotripsy for stones >10 mm. A higher initial stone-free rate and lower retreatment rate were found for those treated ureteroscopically; complications were similar between the 2 groups. An important consideration, alluded to in the discussion, is that shock wave lithotripsy technology has remained stagnant with the Dornier HM3 lithotripter, still considered the gold standard in terms of efficacy.

Shock wave lithotripsy does not impair renal function in a Swine model of metabolic syndrome.

To determine whether shock wave lithotripsy (SWL) may be a risk factor for renal functional impairment in a swine model of metabolic syndrome (MetS). Nine-month-old female Ossabaw pigs were fed an excess calorie atherogenic diet to induce MetS. At 15 months of age, the MetS pigs were treated with 2000 SWs or an overtreatment dose of 4000 SWs targeted at the upper pole calyx of the left kidney (24 kV at 120 SWs/min using the unmodified Dornier HM3 lithotripter; n=5-6 per treatment group). Serum creatinine (Cr) and blood urea nitrogen (BUN) levels were measured in conscious pigs before and ∼60 days after SWL to provide a qualitative assessment of how well both kidneys were filtering (glomerular filtration rate [GFR]). Bilateral renal function was assessed at ∼65 days post-SWL in anesthetized pigs with GFR and effective renal plasma flow (ERPF) quantified by the renal clearance of inulin and para-amino hippurate, respectively. Cr and BUN values were within normal limits before SWL and remained unchanged after lithotripsy in both the 2000 SW- and 4000 SW-treated pigs. GFR and ERPF of kidneys treated with SWL at either SW dose were similar to the contralateral nontreated kidney. Chronic histological changes in the SW-treated pole of the kidney included interstitial fibrosis, sclerotic glomeruli, and dilated and atrophic tubules. Our results are consistent with the view that a single SWL session does not result in renal impairment, even in the presence of MetS.

Comparison of Tissue Injury from Focused Ultrasonic Propulsion of Kidney Stones Versus Extracorporeal Shock Wave Lithotripsy

Focused ultrasonic propulsion is a new noninvasive technique designed to move kidney stones and stone fragments out of the urinary collecting system. However, to our knowledge the extent of tissue injury associated with this technique is not known. We quantitated the amount of tissue injury produced by focused ultrasonic propulsion under simulated clinical treatment conditions and under conditions of higher power or continuous duty cycles. We compared those results to extracorporeal shock wave lithotripsy injury. A human calcium oxalate monohydrate stone and/or nickel beads were implanted by ureteroscopy in 3 kidneys of live pigs weighing 45 to 55 kg and repositioned using focused ultrasonic propulsion. Additional pig kidneys were exposed to extracorporeal shock wave lithotripsy level pulse intensity or continuous ultrasound exposure 10 minutes in duration using an ultrasound probe transcutaneously or on the kidney. These kidneys were compared to 6 treated with an unmodified Dornier HM3 lithotripter (Dornier Medical Systems, Kennesaw, Georgia) using 2,400 shocks at 120 shock waves per minute and 24 kV. Histological analysis was performed to assess the volume of hemorrhagic tissue injury created by each technique according to the percent of functional renal volume. Extracorporeal shock wave lithotripsy produced a mean ± SEM lesion of 1.56% ± 0.45% of functional renal volume. Ultrasonic propulsion produced no detectable lesion with simulated clinical treatment. A lesion of 0.46% ± 0.37% or 1.15% ± 0.49% of functional renal volume was produced when excessive treatment parameters were used with the ultrasound probe placed on the kidney. Focused ultrasonic propulsion produced no detectable morphological injury to the renal parenchyma when using clinical treatment parameters but produced injury comparable in size to that of extracorporeal shock wave lithotripsy when using excessive treatment parameters.

1553 COMPARISON OF TISSUE INJURY FROM A NOVEL TECHNIQUE OF FOCUSED ULTRASONIC PROPULSION OF KIDNEY STONES VERSUS EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY

You have accessJournal of UrologyStone Disease: New Technology1 Apr 20131553 COMPARISON OF TISSUE INJURY FROM A NOVEL TECHNIQUE OF FOCUSED ULTRASONIC PROPULSION OF KIDNEY STONES VERSUS EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY Bret Connors, Andrew Evan, Philip Blomgren, Ryan Hsi, Jonathan Harper, Mathew Sorensen, Yak-Nam Wang, Julianna Simon, Marla Paun, Frank Starr, Bryan Cunitz, and Michael Bailey Bret ConnorsBret Connors Indianapolis, IN More articles by this author , Andrew EvanAndrew Evan Indianapolis, IN More articles by this author , Philip BlomgrenPhilip Blomgren Indianapolis, IN More articles by this author , Ryan HsiRyan Hsi Seattle, WA More articles by this author , Jonathan HarperJonathan Harper Seattle, WA More articles by this author , Mathew SorensenMathew Sorensen Seattle, WA More articles by this author , Yak-Nam WangYak-Nam Wang Seattle, WA More articles by this author , Julianna SimonJulianna Simon Seattle, WA More articles by this author , Marla PaunMarla Paun Seattle, WA More articles by this author , Frank StarrFrank Starr Seattle, WA More articles by this author , Bryan CunitzBryan Cunitz Seattle, WA More articles by this author , and Michael BaileyMichael Bailey Seattle, WA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.3063AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Focused ultrasonic propulsion is a new technique designed to move kidney stones and stone fragments out of the upper urinary collecting system. It is similar to extracorporeal shock wave lithotripsy (SWL) in that both techniques are transcutaneous with acoustic energy originating from an extracorporeal source. However, ultrasonic propulsion generates pulses with substantially lower pressures (20 MPa versus 35-110 MPa), and lower total energy delivered into a kidney for a standard 20-40 min treatment (25-50 J versus 100-200 J) compared to SWL. As such, the injury from ultrasound propulsion would be expected to be lower than SWL. The purpose of this study was to compare the amount of tissue injury produced by focused ultrasound propulsion versus SWL. METHODS Human calcium oxalate monohydrate stones and/or nickel beads were implanted (with ureteroscopy) into 4 kidneys of live pigs (45-55 kg), and repositioned using focused ultrasound propulsion. These kidneys were compared to 12 kidneys treated with an unmodified Dornier HM3 Lithotripter (2400 shocks at 120 SWs/min and 24 kV). After treatment, all kidneys were perfusion-fixed with gluteraldehyde, injected with Microfil, and embedded in paraffin. The kidneys were then serial-sectioned into 10 μm-thick slices, and digital reconstructions were created from photographs of each section. Analysis was performed to assess the volume of tissue injury created by each technique (% functional renal volume, FRV). RESULTS Treatment parameters for the ultrasonic propulsion group averaged 124±30 pulses delivered for a total push burst time of 103±17 seconds per kidney. All stones/beads demonstrated movement. The ultrasonic propulsion technique achieved a 75% clearance rate defined as repositioning of the stone or bead from a calyx into the renal pelvis or ureter. Ultrasonic propulsion produced no detectable lesion compared to 1.08±0.38% FRV for the SWL group. CONCLUSIONS Compared to SWL, focused ultrasonic propulsion produced no detectable tissue injury to the renal parenchyma when using clinical treatment parameters. Efforts are now underway for FDA approval of human feasibility studies of the ultrasonic propulsion technique. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e637 Peer Review Report Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Bret Connors Indianapolis, IN More articles by this author Andrew Evan Indianapolis, IN More articles by this author Philip Blomgren Indianapolis, IN More articles by this author Ryan Hsi Seattle, WA More articles by this author Jonathan Harper Seattle, WA More articles by this author Mathew Sorensen Seattle, WA More articles by this author Yak-Nam Wang Seattle, WA More articles by this author Julianna Simon Seattle, WA More articles by this author Marla Paun Seattle, WA More articles by this author Frank Starr Seattle, WA More articles by this author Bryan Cunitz Seattle, WA More articles by this author Michael Bailey Seattle, WA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Optimising an escalating shockwave amplitude treatment strategy to protect the kidney from injury during shockwave lithotripsy

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Animal studies have shown that one approach to reduce SWL-induced renal injury is to pause treatment for 3-4 min early in the SWL-treatment protocol. However, there is typically no pause in treatment during clinical lithotripsy. We show in a porcine model that a pause in SWL treatment is unnecessary to achieve a reduction in renal injury if treatment is begun at a low power setting that generates low-amplitude SWs, and given continuously for ≈ 4 min before applying higher-amplitude SWs. • To test the idea that a pause (≈ 3 min) in the delivery of shockwaves (SWs) soon after the initiation of SW lithotripsy (SWL) is unnecessary for achieving a reduction in renal injury, if treatment is begun at a low power setting that generates low-amplitude SWs. • Anaesthetised female pigs were assigned to one of three SWL treatment protocols that did not involve a pause in SW delivery of >10 s (2000 SWs at 24 kV; 100 SWs at 12 kV + ≈ 10-s pause + 2000 SWs at 24 kV; 500 SWs at 12 kV + ≈ 10-s pause + 2000 SWs at 24 kV). • All SWs were delivered at 120 SWs/min using an unmodified Dornier HM3 lithotripter. • Renal function was measured before and after SWL. • The kidneys were then processed for quantification of the SWL-induced haemorrhagic lesion. Values for lesion size were compared to previous data collected from pigs in which treatment included a 3-min pause in SW delivery. • All SWL treatment protocols produced a similar degree of vasoconstriction (23-41% reduction in glomerular filtration rate and effective renal plasma flow) in the SW-treated kidney. • The mean renal lesion in pigs treated with 100 low-amplitude SWs delivered before the main dose of 2000 high-amplitude SWs (2.27% functional renal volume [FRV]) was statistically similar to that measured for pigs treated with 2000 SWs all at high-amplitude (3.29% FRV). • However, pigs treated with 500 low-amplitude SWs before the main SW dose had a significantly smaller lesion (0.44% FRV) that was comparable with the lesion in pigs from a previous study in which there was a 3-min pause in treatment separating a smaller initial dose of 100 low-amplitude SWs from the main dose of 2000 high-amplitude SWs (0.46% FRV). The time between the initiation of the low - and high-amplitude SWs was ≈ 4 min for these latter two groups compared with ≈ 1 min when there was negligible pause after the initial 100 low-amplitude SWs in the protocol. • Pig kidneys treated by SWL using a two-step low-to-high power ramping protocol were protected from injury with negligible pause between steps, provided the time between the initiation of low-amplitude SWs and switching to high-amplitude SWs was ≈ 4 min. • Comparison with results from previous studies shows that protection can be achieved using various step-wise treatment scenarios in which either the initial dose of SWs is delivered at low-amplitude for ≈ 4 min, or there is a definitive pause before resuming SW treatment at higher amplitude. • Thus, we conclude that renal protection can be achieved without instituting a pause in SWL treatment. It remains prudent to consider that renal protection depends on the acoustic and temporal properties of SWs administered at the beginning stages of a SWL ramping protocol, and that this may differ according to the lithotripter being used.

Evaluation of shock wave lithotripsy injury in the pig using a narrow focal zone lithotriptor

What's known on the subject? and What does the study add? Of all the SW lithotriptors manufactured to date, more research studies have been conducted on and more is known about the injury (both description of injury and how to manipulate injury size) produced by the Dornier HM-3 than any other machine. From this information have come suggestions for treatment protocols to reduce shock wave (SW)-induced injury for use in stone clinics. By contrast, much less is known about the injury produced by narrow-focus and high-pressure lithotriptors like the Storz Modulith SLX. In fact, a careful study looking at the morphology of the injury produced by the SLX itself is lacking, as is any study exploring ways to reduce renal injury by manipulating SW delivery variables of this lithotriptor. The present study quantitates the lesion size and describes the morphology of the injury produced by the SLX. In addition, we report that reducing the SW delivery rate, a manoeuvre known to lower injury in the HM-3, does not reduce lesion size in the SLX. • To assess renal injury in a pig model after treatment with a clinical dose of shock waves using a narrow focal zone (≈3 mm) lithotriptor (Modulith SLX, Karl Storz Lithotripsy). • The left kidney of anaesthetized female pigs were treated with 2000 or 4000 shock waves (SWs) at 120 SWs/min, or 2000 SWs at 60 SWs/min using the Storz SLX. • Measures of renal function (glomerular filtration rate and renal plasma flow) were collected before and 1 h after shock wave lithotripsy (SWL) and the kidneys were harvested for histological analysis and morphometric quantitation of haemorrhage in the renal parenchyma with lesion size expressed as a percentage of functional renal volume (FRV). • A fibre-optic probe hydrophone was used to determine acoustic output and map the focal width of the lithotriptor. • Data for the SLX were compared with data from a previously published study in which pigs of the same age (7-8 weeks) were treated (2000 SWs at 120 or 60 SWs/min) using an unmodified Dornier HM3 lithotriptor. • Treatment with the SLX produced a highly focused lesion running from cortex to medulla and often spanning the full thickness of the kidney. Unlike the diffuse interstitial haemorrhage observed with the HM3, the SLX lesion bore a blood-filled core of near-complete tissue disruption devoid of histologically recognizable kidney structure. • Despite the intensity of tissue destruction at the core of the lesion, measures of lesion size based on macroscopic determination of haemorrhage in the parenchyma were not significantly different from kidneys treated using the HM3 (2000 SWs, 120 SWs/min: SLX, 1.86 ± 0.52% FRV; HM3, 3.93 ± 1.29% FRV). • Doubling the SW dose of the SLX from 2000 to 4000 SWs did not significantly increase lesion size. In addition, slowing the firing rate of the SLX to 60 SWs/min did not reduce the size of the lesion (2.16 ± 0.96% FRV) compared with treatment at 120 SWs/min, as was the case with the HM3 (0.42 ± 0.23% FRV vs 3.93 ± 1.29% FRV). • Renal function fell significantly below baseline in all treated groups but was similar for both lithotriptors. • Focal width of the SLX (≈2.6 mm) was about one-third that of the HM3 (≈8 mm) while peak pressures were higher (SLX at power level 9: P+≈90 MPa, P-≈-12 MPa; HM3 at 24 kV: P+≈46 MPa, P-≈-8 MPa). • The lesion produced by the SLX (narrow focal width, high acoustic pressure) was a more focused, more intense form of tissue damage than occurs with the HM3. • Slowing the SW rate to 60 SWs/min, a strategy shown to be effective in reducing injury with the HM3, was not protective with the SLX. • These findings suggest that the focal width and acoustic output of a lithotriptor affect the renal response to SWL.

1837 SHOCKWAVE LITHOTRIPSY: IS ITS CURRENT EFFICACY OVERESTIMATED? AN INVESTIGATION OF SUCCESS AND RETREATMENT FOR BOTH FIRST- AND FOURTH-GENERATION LITHOTRIPTERS

You have accessJournal of UrologyStone Disease: New Technology/SWL, Ureteroscopic or Percutaneous Stone Removal1 Apr 20111837 SHOCKWAVE LITHOTRIPSY: IS ITS CURRENT EFFICACY OVERESTIMATED? AN INVESTIGATION OF SUCCESS AND RETREATMENT FOR BOTH FIRST- AND FOURTH-GENERATION LITHOTRIPTERS Brian Benway, Timur Roytman, Robert Figenshau, Sam Bhayani, and Alana Desai Brian BenwayBrian Benway St. Louis, MO More articles by this author , Timur RoytmanTimur Roytman St. Louis, MO More articles by this author , Robert FigenshauRobert Figenshau St. Louis, MO More articles by this author , Sam BhayaniSam Bhayani St. Louis, MO More articles by this author , and Alana DesaiAlana Desai St. Louis, MO More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1856AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Shockwave lithotripsy (SWL) is one accepted modality for the treatment of renal and ureteral calculi, with reported success rates historically on par with ureteroscopic intervention. However, at our institution, we have witnessed what we believe to be a sharp decrease in efficacy of SWL for stones <1.5cm. We therefore sought to evaluate contemporary outcomes of SWL performed with both first- and fourth-generation lithotripters from January 2007 through January 2009. METHODS An interim analysis of patients undergoing SWL between 2007 and 2009 was performed. Only patients with follow-up at our institution were included. Of the 53 patients who met inclusion criteria, 26 patients were treated with the first-generation Dornier HM3 lithotripter, and 27 were treated using the fourth-generation Storz Modulith F2. Outcomes, including stone clearance, postoperative complications, and retreatments were evaluated. RESULTS The two patient populations were equivalent across all measured demographic parameters, including age, BMI, comorbidity, stone size, and composition. Mean stone size for the HM3 group was 12.1mm, and 11.5 for the F2 cohort (p=0.7). Stone composition was predominantly calcium oxalate monohydrate. Skin-to-stone distance for HM3 and F2 was 12.5 and 11.4cm, respectively (p=0.3). Success, as determined by residual fragment size <2 mm was 47% for the HM3 and 39% for the F2; this difference was not statistically significant (p=0.6). 27% of HM3 and 19% of F2 patients required emergent evaluation or re-admission. Retreatment was required in 50% and 52% of patients treated with the HM3 and F2, respectively (p=0.5). CONCLUSIONS In our sampling analysis, SWL in the modern era appears to be associated with a marked decrease in efficacy over historically-reported outcomes, with half of patients now requiring retreatment. Even more surprisingly, this decline appears to be independent of lithotripter generation, suggesting perhaps that changes in patient characteristics and stone composition, and not technology may be to blame. Further study is critically needed. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e736 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Brian Benway St. Louis, MO More articles by this author Timur Roytman St. Louis, MO More articles by this author Robert Figenshau St. Louis, MO More articles by this author Sam Bhayani St. Louis, MO More articles by this author Alana Desai St. Louis, MO More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

A Prospective Randomised Trial Comparing the Modified HM3 with the MODULITH® SLX-F2 Lithotripter

BackgroundThe relative efficacy of first- versus last-generation lithotripters is unknown. ObjectivesTo compare the clinical effectiveness and complications of the modified Dornier HM3 lithotripter (Dornier MedTech, Wessling, Germany) to the MODULITH® SLX-F2 lithotripter (Storz Medical AG, Tägerwilen, Switzerland) for extracorporeal shock wave lithotripsy (ESWL). Design, setting and participantsWe conducted a prospective, randomised, single-institution trial that included elective and emergency patients. InterventionsShock wave treatments were performed under anaesthesia. MeasurementsStone disintegration, residual fragments, collecting system dilatation, colic pain, and possible kidney haematoma were evaluated 1 d and 3 mo after ESWL. Complications, ESWL retreatments, and adjuvant procedures were documented. Results and limitationsPatients treated with the HM3 lithotripter (n=405) required fewer shock waves and shorter fluoroscopy times than patients treated with the MODULITH® SLX-F2 lithotripter (n=415). For solitary kidney stones, the HM3 lithotripter produced a slightly higher stone-free rate (p=0.06) on day 1; stone-free rates were not significantly different at 3 mo (HM3: 74% vs MODULITH® SLX-F2: 67%; p=0.36). For solitary ureteral stones, the stone-free rate was higher at 3 mo with the HM3 lithotripter (HM3: 90% vs MODULITH® SLX-F2: 81%; p=0.05). For solitary lower calyx stones, stone-free rates were equal at 3 mo (63%). In patients with multiple stones, the HM3 lithotripter’s stone-free rate was higher at 3 mo (HM3: 64% vs MODULITH® SLX-F2: 44%; p=0.003). Overall, HM3 lithotripter led to fewer secondary treatments (HM3: 11% vs MODULITH® SLX-F2: 19%; p=0.001) and fewer kidney haematomas (HM3: 1% vs. MODULITH® SLX-F2: 3%; p=0.02). ConclusionsThe modified HM3 lithotripter required fewer shock waves and shorter fluoroscopy times, showed higher stone-free rates for solitary ureteral stones and multiple stones, and led to fewer kidney haematomas and fewer secondary treatments than the MODULITH® SLX-F2 lithotripter. In patients with a solitary kidney and solitary lower calyx stones, results were comparable for both lithotripters.

What Happened to Shockwave Lithotripsy During the Past 22 Years? A Single-Center Experience

From 1985 to August 2007 we have performed 15,324 shockwave lithotripsy (SWL) treatments using the Dornier HM3 lithotripter. We studied trends in the characteristics of treatments and patients. Patient data were recorded in a computerized database. Changes in characteristics of patients and stones treated during this period were reviewed. A total of 15,324 treatments were performed on 10,734 patients. The following trends were observed: (1) Stone size: A significant increase in the proportion of patients treated for stones up to 10 mm in diameter, no change for stone size of 10 to 20 mm, and a decrease in stones larger than 20 mm in diameter. (2) Stone location: A significant increase in the proportion of patients treated for proximal and distal ureteral calculi, whereas a significant decrease in those with renal pelvic and staghorn stones. (3) Auxiliary procedures: A significant increase in the use of perioperative procedures (stents or ureteral catheters) ranging from 20% during the mid-1980s up to 60% in the year 2007. (4) Presenting symptoms: A significant increase in the percentage of patients referred with pain and a significant decrease in the percentage of patients referred with signs of infection. (5) Repeat SWL: A total of 13% of the patients required a second SWL for the same stone within 90 days of the first procedure. (6) Complication rate: This rate was relatively low, ranging from 1% to 6% per year. The evolvement of endourological procedures and techniques resulted in a decreased referral of large kidney stones for SWL. Advanced diagnostic modalities increased the diagnosis of renal colic in patients presenting with pain, and consequently their referral rate and timing for SWL treatment. The use of stents increased because of referral of patients with obstructing stones and infection or for prevention of posttreatment obstruction.

Fever after shockwave lithotripsy: risk factors and indications for prophylactic antimicrobial treatment

J Endourol. 2010; 24: 277-81.Purpose: To identify risk factors for fever after shockwave lithotripsy (SWL) and suggest guidelines for pro-phylactic antimicrobial treatment. Patients and Methods: Between 1985 and 2007, a total of 15,324 SWL procedures were performed in our institution using the Dornier HM3 lithotripter. Because stone analyses were not available in the majority of patients, management of stones larger than 2 cm in diameter were excluded from this analysis to minimize the ratio of struvite stones as a possible cause for postprocedural fever. In this analysis, 11,500 SWL treatments were included. Clinical parameters before, during, and after treatments were prospectively registered using a computerized database. Potential risk factors for fever after SWL were evaluated. Results: Fever >38.0 degrees C developed in 161 (1.4%) patients. The risk factors for fever after SWL were: A positive urine culture (P 38.0 degrees C) develops in only 1.4% of the patients undergoing SWL. Therefore, pro-phylactic antibiotic treatment is not indicated in all patients. Selective prophylactic treatment is recommended in patients who present with UTI, kidney or upper ureteral stones, and those for whom a nephrostomy tube or stent is necessary.

Fever After Shockwave Lithotripsy—Risk Factors and Indications for Prophylactic Antimicrobial Treatment

To identify risk factors for fever after shockwave lithotripsy (SWL) and suggest guidelines for prophylactic antimicrobial treatment. Between 1985 and 2007, a total of 15,324 SWL procedures were performed in our institution using the Dornier HM3 lithotripter. Because stone analyses were not available in the majority of patients, management of stones larger than 2 cm in diameter were excluded from this analysis to minimize the ratio of struvite stones as a possible cause for postprocedural fever. In this analysis, 11,500 SWL treatments were included. Clinical parameters before, during, and after treatments were prospectively registered using a computerized database. Potential risk factors for fever after SWL were evaluated. Fever >38.0 degrees C developed in 161 (1.4%) patients. The risk factors for fever after SWL were: A positive urine culture (P < 0.05), an indwelling nephrostomy tube or stent during the procedure (P < 0.001), lithotripsy of kidney or upper ureteral stones (P < 0.05) and preoperative symptomatic urinary tract infection (UTI) (P < 0.05) or sepsis (P < 0.05). Lithotripsy of mid and lower ureteral stones, stone size, and the use of ureteral catheters during the procedures were not associated with increased risk of fever after SWL. Fever (>38.0 degrees C) develops in only 1.4% of the patients undergoing SWL. Therefore, prophylactic antibiotic treatment is not indicated in all patients. Selective prophylactic treatment is recommended in patients who present with UTI, kidney or upper ureteral stones, and those for whom a nephrostomy tube or stent is necessary.

Extracorporeal Shock Wave Lithotripsy for Renal Calculi

To gain better understanding of ESWL efficacy in children with renal calculi we report our outcomes using this technique. We reviewed the records of children who underwent ESWL as monotherapy for renal calculi at our institution from 1988 to 2007. Data included clinical characteristics, stone-free rate and its relationship to stone size and location, lithotriptor and complications. The 33 boys and 29 girls with an average age of 10 years underwent a total of 69 treatments. A 53% and 63% stone-free rate was achieved after 1 and 2 ESWL sessions, respectively. A trend toward a higher stone-free rate (61% to 70%) after 1 ESWL session was seen in children with stones less than 50 mm(2), renal pelvic stones and treatment with the Dornier HM3 lithotriptor. Children with stones greater than 100 mm(2), a caliceal location and those treated with the Dornier MFL 5000 lithotriptor had a higher failure rate (25% to 46%). Five patients (8%) required ureteroscopy after ESWL due to retained distal ureteral stone fragments. Five patients (8%) who were not stone-free after therapy required subsequent endoscopic treatment for the stone during followup. Smaller renal stones, renal pelvic calculi and treatment with an older generation lithotriptor were independent variables associated with a higher stone-free rate in children. While ESWL is a simple method in children with renal calculi, those with large or caliceal stones may do best with a primary endoscopic approach.

Renal heme oxygenase-1 upregulation after shock wave lithotripsy.

Shock wave lithotripsy (SWL) is known to induce oxidative stress and a rapid inflammatory response in renal tissue. The purpose of this study was to determine the location and quantify markers for oxidative stress and inflammation in a porcine model of acute SWL-induced renal injury. The lower pole calyx of left kidneys of female pigs received 2000 shock waves at 24 kV/2 Hz from a Dornier HM3 lithotripter and subsequently monitored for 4 h. Heme oxygenase-1 protein (HO-1) was measured in renal microsomes by Western blot. Renal medulla HO-1/β-actin ratios were 1.186 ± 0.48 for treated pole (F2), 0.293 ± 0.23 for treated kidney upper pole, and 0.122 ± 0.075 for contralateral kidney (n=6). Thus, we observed an eightfold induction of HO-1 in renal medulla at F2 compared to the upper pole medulla of the treated kidney and the contralateral kidney medulla. In contrast, renal cortex at F2 did not show a similar HO-1 induction. The highly localized HO-1 induction in SWL-treated renal medulla parallels our previously reported finding of interleukin-6. These data together suggest that an early inflammatory response and oxidative stress appear primarily in the treated renal medulla within 4 h after SWL. [Work supported by NIH].

In-Situ Extracorporeal Shock Wave Lithotripsy (ESWL) for Ureteral Calculi in Prepubertal Children: 22 Year Experience of A Single Institiution With A Single Lithotriptor

Purpose The recent advancements in ureteroscopy, with reported success rate between 77% and 100%, have challenged the efficacy of ESWL monotherapy for ureterolithiasis in prepubertal children (PC). We, therefore, evaluated our long-term experience with ESWL in these patients, and determined its efficiency. Material and Methods We conducted a retrospective chart evaluation, and retrieved all PC who underwent ESWL for ureteral stones. The need for tubing, 3 month stone free rate (3SFR), the need for additional ESWL sessions, and the effect of stone size and location were evaluated. Results Fifty nine patients (32 males, 27 females; mean age 7.3 years, range 10 months to 12 years) underwent in-situ ESWL by the unmodified Dornier HM3 lithotriptor for ureteral calculi between 1986 and 2008. All patients required general anesthesia for their treatment. Average stone length was 9.5 mm (S.D. 4.8 mm). In 41 children (69%) a tube was inserted prior or during the procedure; A nephrostomy, a double pigtail ureteral stent, or an externalized ureteral catheter were inserted in 6 (14%), 9 (22%), and 23 (63%) patients respectively. All ureteral catheters were removed at the end of the procedure. 3SFR was 78%, and 13 patients (22%) required an additional procedure with subsequent total 96.5% and 98.3% SFR after a 2nd and a 3rd ESWL. SFR was not dependent on patients’ age, stone location (proximal, mid or distal), or stone size. Conclusions The 3SFR after ESWL monotherapy for ureteral stones in PC is only 78% regardless of the necessity for tubing in 69% of them. Therefore, ESWL does not have an advantage over ureteroscopy in this population. Recent reported results of ureteroscopy in PC place this modality equal, and even superior to ESWL.

STRATEGIES TO IMPROVE SWL FOR OBESE PATIENTS: IN VITRO ASSESSMENT OF TARGETING STONES ALONG THE DISTAL ACOUSTIC AXIS

Initial clinical experience with the use of an optical fibre hydrophone for in vivo ultrasound dosimetry is reported. The hydrophone, originally described by Beard and Mills (1997), operates as an extrinsic, low-finesse Fabry-Perot optical sensor where acoustically-induced thickness changes in a polymer film modulate the phase difference between light beams reflected from the two surfaces of the film. The pressure waveforms from the sensor are compared with those from a calibrated piezoelectric polymer membrane hydrophone. The sensor is found to have a frequency resonance at around 12 MHz, corresponding to the thickness mode of the 50-μm polymer film. The directional responses at 0.16 MHz, 1.0 MHz and 5.0 MHz are found to be similar to those predicted for a plane piston receiver with the same diameter as that of the polymer film (400 μm). The performance of the sensor as a broad-band hydrophone is degraded by the relatively low acoustical impedance of the adhesive used in the fibre-film bond. The hydrophone was used in the clinic for measurement of acoustic pressures within the ureter of 4 patients undergoing clinical extracorporeal shock-wave lithotripsy on a Dornier HM3 lithotripter. Pressures in the range 0.5 to 5.0 MPa were recorded in the ureter at positions over 10 cm from the renal pelvis. Problems related to the clinical use of the sensor, including instability in the sensitivity of the sensor following handling and its mechanical strength in high-amplitude acoustic fields, are discussed.

Effect of initial shock wave voltage on shock wave lithotripsy‐induced lesion size during step‐wise voltage ramping

To determine if the starting voltage in a step-wise ramping protocol for extracorporeal shock wave lithotripsy (SWL) alters the size of the renal lesion caused by the SWs. To address this question, one kidney from 19 juvenile pigs (aged 7-8 weeks) was treated in an unmodified Dornier HM-3 lithotripter (Dornier Medical Systems, Kennesaw, GA, USA) with either 2000 SWs at 24 kV (standard clinical treatment, 120 SWs/min), 100 SWs at 18 kV followed by 2000 SWs at 24 kV or 100 SWs at 24 kV followed by 2000 SWs at 24 kV. The latter protocols included a 3-4 min interval, between the 100 SWs and the 2000 SWs, used to check the targeting of the focal zone. The kidneys were removed at the end of the experiment so that lesion size could be determined by sectioning the entire kidney and quantifying the amount of haemorrhage in each slice. The average parenchymal lesion for each pig was then determined and a group mean was calculated. Kidneys that received the standard clinical treatment had a mean (sem) lesion size of 3.93 (1.29)% functional renal volume (FRV). The mean lesion size for the 18 kV ramping group was 0.09 (0.01)% FRV, while lesion size for the 24 kV ramping group was 0.51 (0.14)% FRV. The lesion size for both of these groups was significantly smaller than the lesion size in the standard clinical treatment group. The data suggest that initial voltage in a voltage-ramping protocol does not correlate with renal damage. While voltage ramping does reduce injury when compared with SWL with no voltage ramping, starting at low or high voltage produces lesions of the same approximate size. Our findings also suggest that the interval between the initial shocks and the clinical dose of SWs, in our one-step ramping protocol, is important for protecting the kidney against injury.

Effect of Skin-to-Stone Distance on Shockwave Lithotripsy Success

We evaluated the effect of increased body habitus on stone-free rates after shockwave lithotripsy (SWL), determined by three reproducible skin-to-stone distances (SSDs) on CT. We retrospectively reviewed the records of 85 patients with preoperative CT scans available on Stentor Radiology Imaging who underwent SWL with the unmodified Dornier HM3 lithotripter from 2002 to 2007. SSDs were measured at the following angles: 0 degrees (vertical), 30 degrees, and 90 degrees (horizontal). Successful therapy was defined as stone free (residual fragments <2 mm) on follow-up imaging. Data were analyzed using descriptive statistics, Student t test, and the Fisher exact test. Four hundred and eighty patients underwent SWL at our institution from 2002 to 2007; 85 patients (50.6% men, mean age 50.8 +/- 15.7 years, mean body mass index [BMI] 28.8 +/- 6.6 kg/m2) had preoperative CT scans available for review. On follow-up imaging (142.7 +/- 217.2 days), 49.4% of patients were stone free. Mean SSDs (vertical, 30 degrees, horizontal) in patients who were stone-free v those with residual stone were 104.3 +/- 26.2 mm v 102.6 +/- 29.9 mm (P = 0.79), 103.9 +/- 28.2 mm v 101.0 +/- 31.5 mm (P = 0.66), and 106.6 +/- 25.3 mm v 107.1 +/- 29.3 mm (P = 0.94), respectively. Multiple variables have been shown to be associated with SWL success. In our sample of patients with preoperative CT scans, SSD was found to have no effect on SWL success.