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  1. Damage mechanisms in shock wave lithotripsy (SWL)

    NASA Astrophysics Data System (ADS)

    Lokhandwalla, Murtuza

    Shock wave lithotripsy is a 'non-invasive' therapy for treating kidney stones. Focused shock waves fragment stones to a size that can be passed naturally. There is, however, considerable tissue injury, and the mechanisms of stone fragmentation and tissue injury are not well understood. This work investigates potential tissue damage mechanisms, with an aim towards enhancing stone fragmentation and minimizing tissue damage. Lysis of red blood cells (RBC's) due to in vitro exposure to shock waves was investigated. Fluid flow-fields induced by a non-uniform shock wave, as well as radial expansion/implosion of a bubble was hypothesized to cause cell lysis. Both the above flow-fields constitute an unsteady extensional flow, exerting inertial as well as viscous forces on the RBC membrane. The resultant membrane tension and the membrane areal strain due to the above flow-fields were estimated. Both were found to exert a significantly higher inertial force (50--100 mN/m) than the critical membrane tension (10 mN/m). Bubble-induced flow-field was estimated to last for a longer duration (˜1 microsec) compared to the shock-induced flow (˜1 ns) and hence, was predicted to be lytically more effective, in typical in vitro experimental conditions. However, in vivo conditions severely constrain bubble growth, and cell lysis due to shock-induced shear could be dominant. Hemolysis due to shock-induced shear, in absence of cavitation, was experimentally investigated. The lithotripter-generated shock wave was refocused by a parabolic reflector. This refocused wave-field had a tighter focus (smaller beam-width and a higher amplitude) than the lithotripter wave-field. Cavitation was eliminated by applying overpressure to the fluid. Acoustic emissions due to bubble activity were monitored by a novel passive cavitation detector (HP-PCD). Aluminum foils were also used to differentiate cavitational from non-cavitational mode of damage. RBC's were exposed to the reflected wave-field from the parabolic reflector and also from a flat reflector, the latter serving as a control experiment. Exposure to the wave-field from the parabolic reflector increased hemolysis four-fold compared to untreated controls and was twice that of cell lysis with the flat reflector. This result corroborated the hypothesis of shock-induced shear as a damage mechanism.

  2. Shock wave lithotripsy (SWL) induces significant structural and functional changes in the kidney

    NASA Astrophysics Data System (ADS)

    Evan, Andrew P.; Willis, Lynn R.; Lingeman, James E.

    2003-10-01

    The foundation for understanding SWL-injury has been well-controlled renal structural and functional studies in pigs, a model that closely mimics the human kidney. A clinical dose (2000 shocks at 24 kV) of SWL administered by the Dornier HM3 induces a predictable, unique vascular injury at F2 that is associated with transient renal vasoconstriction, seen as a reduction in renal plasma flow, in both treated and untreated kidneys. Unilateral renal denervation studies links the fall in blood flow in untreated kidneys to autonomic nerve activity in the treated kidney. SWL-induced trauma is associated with an acute inflammatory process, termed Lithotripsy Nephritis and tubular damage at the site of damage that leads to a focal region of scar. Lesion size increases with shock number and kV level. In addition, risk factors like kidney size and pre-existing renal disease (e.g., pyelonephritis), can exaggerate the predicted level of renal impairment. Our new protection data show that lesion size can be greatly reduced by a pretreatment session with low kV and shock number. The mechanisms of soft tissue injury probably involves shear stress followed by acoustic cavitation. Because of the perceived enhanced level of bioeffects from 3rd generation lithotripters, these observations are more relevant than ever.

  3. Using Helical CT to Predict Stone Fragility in Shock Wave Lithotripsy (SWL)

    SciTech Connect

    Williams, James C. Jr.; Zarse, Chad A.; Jackson, Molly E.; McAteer, James A.; Lingeman, James E.

    2007-04-05

    Great variability exists in the response of urinary stones to SWL, and this is true even for stones composed of the same mineral. Efforts have been made to predict stone fragility to shock waves using computed tomography (CT) patient images, but most work to date has focused on the use of stone CT number (i.e., Hounsfield units). This is an easy number to measure on a patient stone, but its value depends on a number of factors, including the relationship of the size of the stone to me resolution (i.e., the slicewidth) of the CT scan. Studies that have shown a relationship between stone CT number and failure in SWL are reviewed, and all are shown to suffer from error due to stone size, which was not accounted for in the use of Hounsfield unit values. Preliminary data are then presented for a study of calcium oxalate monohydrate (COM) stones, in which stone structure-rather than simple CT number values-is shown to correlate with fragility to shock waves. COM stones that were observed to have structure by micro CT (e.g., voids, apatite regions, unusual shapes) broke to completion in about half the number of shock waves required for COM stones that were observed to be homogeneous in structure by CT. This result suggests another direction for the use of CT in predicting success of SWL: the use of CT to view stone structure, rather than simply measuring stone CT number. Viewing stone structure by CT requires the use of different viewing windows than those typically used for examining patient scans, but much research to date indicates that stone structure can be observed in the clinical setting. Future clinical studies will need to be done to verify the relationship between stone structure observed by CT and stone fragility in SWL.

  4. Complementary approaches to decreasing discomfort during shockwave lithotripsy (SWL).

    PubMed

    Ngee-Ming, Goh; Tamsin, Drake; Rai, B P; Somani, B K

    2014-06-01

    Shock wave lithotripsy (SWL) is an established treatment for renal stones. Although non-invasive, it can cause significant pain and anxiety during the procedure. Our purpose was to review the literature to look at the effect of complimentary therapy in patients undergoing SWL and whether it led to a reduction in the requirement of analgesics and anxiolytics. A systematic review was performed on the use of acupuncture, auricular acupressure, transcutaneous electrical nerve stimulation (TENS) and music during SWL. Only prospective randomized controlled trials were selected. Two reviewers independently extracted the data from each study. Outcomes relating to analgesia requirement, anxiety and stone-free rates (SFR) were compared. Seven papers were identified reporting on 591 patients (acupuncture-3, TENS-1 and music-3). Pain control/analgesia requirement was significantly better in four studies (music-2, acupuncture-1, TENS-1). Significantly lower anxiety was noted in one study with music and two using acupuncture. No difference in SFR was noted with the use of complementary therapy. No major or minor side effects were noted. Complementary therapy for SWL can help lower analgesia requirement and the anxiety associated with it. However, it does not have any effect on the SFR. PMID:24648110

  5. Is the gravity effect of radiographic anatomic features enough to justify stone clearance or fragments retention following extracorporeal shock wave lithotripsy (SWL).

    PubMed

    Mustafa, Mahmoud

    2012-08-01

    We determined whether the gravity effect of radiographic anatomic features on the preoperative urography (IVP) are enough to predict fragments clearance after shock wave lithotripsy (SWL). A Total of 282 patients with mean age 45.8 ± 13.2 years (189 male, 93 female), who underwent SWL due to renal calculi between October 2005 and August 2009 were enrolled. The mean calculi load was 155.72 ± 127.66 mm². The patients were stratified into three groups: patients with pelvis calculi (group 1); patients with upper or middle pole calculi (group 2) and patients with lower pole calculi (group 3). Three angles on the pretreatment IVP were measured: the inner angle between the axis of the lower pole infundibular and ureteropelvic axis (angle I); the inner angle between the lower pole infundibular axis and main axis of pelvis-ureteropelvic (UP) junction point (angle II) and the inner angle between the lower pole infundibular axis and perpendicular line (angle III). Multivariate analysis was used to define the significant predictors of stone clearance. The overall success rate was 85.81%. All angles, sessions number, shock waves number and stone burden were significant predictors of success in patients in group 1. However, in group 2 only angle II and in group 3 angles I and II had significant effect on stone clearance. Radiographic anatomic features have significant role in determining the stone-free rate following satisfactory fragmentation of renal stones with SWL. The measurement of infundibulopelvic angle in different manner helps to predict the stone-free status in patients with renal calculi located not only in lower pole, but also in renal pelvis and upper or middle pole. Gravity effect is not enough to justify the significant influence of the radiographic anatomic features on the stone clearance and fragments retention after SWL. PMID:21847556

  6. Comparison of shock wave lithotripsy (SWL) and retrograde intrarenal surgery (RIRS) for treatment of stone disease in horseshoe kidney patients

    PubMed Central

    Gokce, Mehmet Ilker; Tokatli, Zafer; Suer, Evren; Hajiyev, Parviz; Akinci, Aykut; Esen, Baris

    2016-01-01

    ABSTRACT Objectives In this study it is aimed to compare the success and complication rates of SWL and RIRS in treatment of HSK stone disease. Materials and methods In this retrospective study data of 67 patients treated with either SWL (n=44) or RIRS (n=23) for stone disease in HSK between May 2003 to August 2014 was investigated. age, gender, stone size and multiplicity, stone free status, renal colic episodes and complication rates of the SWL and RIRS groups were compared. Results Mean age of the population was 42.5±8.2 (range: 16-78) years and mean stone size was 16.9±4.1 mm. SWL and RIRS groups were similar with regard to demographic characteristics and stone related characteristics. SFR of the SWL and RIRS groups were 47.7%(21/44 patients) and 73.9% (17/23 patients) respectively (p=0.039).Renal colic episodes were observed in 3 and 16 patients in the RIRS and SWL groups respectively (p=0.024). No statistically significant complications were observed between the SWL (8/44 patients) and RIRS (4/23) groups (p=0.936). Conclusions In HSK patients with stone disease, both SWL and RIRS are effective and safe treatment modalities. However RIRS seems to maintain higher SFRs with comparable complication rates. PMID:27136473

  7. Pretreatment with low-energy shock waves induces renal vasoconstriction during standard SWL: a treatment protocol known to reduce lithotripsy-induced renal injury

    PubMed Central

    Handa, Rajash K.; Bailey, Michael R.; Paun, Marla; Gao, Sujuan; Connors, Bret A.; Willis, Lynn R.; Evan, Andrew P.

    2008-01-01

    Introduction and Objective A great deal of effort has been focused on developing new treatment protocols to reduce tissue injury to improve the safety of shock wave lithotripsy. This has led to the discovery that pretreatment of the kidney with a series of low-energy shock waves (SWs) will substantially reduce the hemorrhagic lesion that normally results from a standard clinical dose of high-energy SWs. Because renal blood flow is reduced following low- or high-energy SWL, and may therefore contribute to this effect, this study was designed to test the hypothesis that the pretreatment protocol induces renal vasoconstriction sooner than the standard protocol for SW delivery. Methods Female farm pigs (6-weeks old) were anesthetized with isoflurane and the lower pole of the right kidney treated with SWs using the HM3 lithotripter. Pulsed Doppler sonography was used to measure resistive index (RI) in blood vessels as a reflection of resistance/impedance to blood flow. RI was recorded from a single intralobar artery located in the targeted pole of the kidney, and measurements taken from pigs given sham SW treatment (Group 1; no SWs, n = 4), a standard clinical dose of high-energy SWs (Group 2; 2000 SWs, 24 kV, 120 SWs/min, n = 7), low-energy SW pretreatment followed by high-energy SWL (Group 3; 500 SWs, 12 kV, 120 SWs/min + 2000 SWs, 24 kV, 120 SWs/min, n = 8) and low-energy SW pretreatment alone (Group 4; 500 SWs, 12 kV, 120 SWs/min, n = 6). Results Baseline RI (~ 0.61) was similar for all groups. Pigs receiving sham SW treatment (Group 1) had no significant change in RI. A standard clinical dose of high-energy SWs (Group 2) did not significantly alter RI during treatment, but did increase RI at 45-min into the post-SWL period. Low-energy SWs did not alter RI in Group 3 pigs, but subsequent treatment with a standard clinical dose of high-energy SWs resulted in a significantly earlier (at 1000 SWs) and greater (two-fold) rise in RI than that observed in Group 2 pigs. This rise in RI during the low/high-energy SWL treatment protocol was not due to a delayed vasoconstrictor response of pretreatment, as low-energy SW treatment alone (Group 4) did not increase RI until 65 min into the post-SWL period. Conclusions The pretreatment protocol induces renal vasoconstriction during the period of SW application whereas the standard protocol shows vasoconstriction occurring only during the post-SWL period. Thus the earlier and greater rise in RI during the pretreatment protocol may be causally associated with a reduction in tissue injury. PMID:19154458

  8. Uncovering the Secret of Shock Wave Lithotripsy

    NASA Astrophysics Data System (ADS)

    Zhong, P.

    Shock wave lithotripsy (SWL) is an engineering innovation that has revolutionized the treatment of kidney stone disease since the early 1980s [1] - [3]. Today, SWL is the first-line therapy for millions of patients worldwide with renal and upper urinary stones [3, 4].

  9. Novel instrumentation in urologic surgery: Shock wave lithotripsy

    PubMed Central

    Semins, Michelle J.; Matlaga, Brian R.

    2010-01-01

    Extracorporeal shock wave lithotripsy (SWL) was first introduced in 1980 and it rapidly revolutionized the treatment of stone disease. SWL is a non-invasive, outpatient procedure that now accounts for the majority of stone removal procedures. Since the introduction of first generation lithotripter, the Dornier HM3 machine, SWL devices have undergone many modifications secondary to limitations, in efforts to create a more effective and efficient way to treat stones and decrease possible morbidities. Herein, we review the evolution of the technology and advances in the instrumentation over the last three decades. PMID:21116366

  10. Extracorporeal shock wave lithotripsy today

    PubMed Central

    Tailly, Geert G

    2013-01-01

    Even 32 years after its first introduction shockwave lithotripsy (SWL) remains a matter of discussion and controversy. Since the first SWL in 1980, millions of treatments have been performed worldwide. To this day SWL remains the least invasive of all stone treatments and is considered the treatment modality of first choice for the majority of urinary stones. Despite the massive scale on which SWL is performed in a wide range of indications, complication rate has always remained very low and usually limited to minor side effects and complications. The introduction of affordable multifunctional lithotripters has made SWL available to more and more departments of urology worldwide. Still many centers are disappointed with the treatment results and concerned about the adverse tissue effects. In this SWL proves to be the victim of its uninvasiveness and its apparent ease of practice. Urologists need proper skill and experience; however, to adequately administer shockwaves in order to improve outcome. This aspect is too often minimized and neglected. Apart from this the power of shockwaves often is underestimated by operators of shockwave machines. Basic knowledge of the physics of shockwaves could further reduce the already minimal adverse tissue effects. Good training and coaching in the administration of shockwaves would no doubt lead to a renaissance of SWL with better treatment results and minimal adverse tissue effects. PMID:24082441

  11. The Efficacy of Medical Expulsive Therapy (MET) in Improving Stone-free Rate and Stone Expulsion Time, After Extracorporeal Shock Wave Lithotripsy (SWL) for Upper Urinary Stones: A Systematic Review and Meta-analysis.

    PubMed

    Skolarikos, Andreas; Grivas, Nikolaos; Kallidonis, Panagiotis; Mourmouris, Panagiotis; Rountos, Thomas; Fiamegos, Alexandros; Stavrou, Sotirios; Venetis, Chris

    2015-12-01

    In this meta-analysis, we included randomized studies on medical expulsive therapy implemented following shock wave lithotripsy for renal and ureteral stones. Pooled results demonstrated the efficacy of α-blockers, nifedipine, Rowatinex, and Uriston in increasing stone clearance. In addition, the time to stone elimination, the intensity of pain, the formation of steinstrasse, and the need for auxiliary procedures were reduced mainly with α-blockers. Expulsion rate was not correlated with the type of α-blocker, the diameter, and the location of stone. Our results show that medical expulsive therapy for residual fragments after shock wave lithotripsy should be implemented in clinical practice. PMID:26383613

  12. Effect of Shock Wave Lithotripsy on Renal Hemodynamics

    NASA Astrophysics Data System (ADS)

    Handa, Rajash K.; Willis, Lynn R.; Evan, Andrew P.; Connors, Bret A.

    2008-09-01

    Extracorporeal shock wave lithotripsy (SWL) can injure tissue and decrease blood flow in the SWL-treated kidney, both tissue and functional effects being largely localized to the region targeted with shock waves (SWs). A novel method of limiting SWL-induced tissue injury is to employ the "protection" protocol, where the kidney is pretreated with low-energy SWs prior to the application of a standard clinical dose of high-energy SWs. Resistive index measurements of renal vascular resistance/impedance to blood flow during SWL treatment protocols revealed that a standard clinical dose of high-energy SWs did not alter RI during SW application. However, there was an interaction between low- and high-energy SWL treatment phases of the "protection" protocol such that an increase in RI (vasoconstriction) was observed during the later half of SW application, a time when tissue damage is occurring during the standard high-energy SWL protocol. We suggest that renal vasoconstriction may be responsible for reducing the degree of tissue damage that normally results from a standard clinical dose of high-energy SWs.

  13. Extracorporeal shock wave lithotripsy: An opinion on its future

    PubMed Central

    Rassweiler, Jens; Rassweiler, Marie-Claire; Frede, Thomas; Alken, Peter

    2014-01-01

    The development of miniaturized nephroscopes which allow one-stage stone clearance with minimal morbidity has brought the role of shock wave lithotripsy (SWL) in stone management into question. Design innovations in SWL machines over the last decade have attempted to address this problem. We reviewed the recent literature on SWL using a MEDLINE/PUBMED research. For commenting on the future of SWL, we took the subjective opinion of two senior urologists, one mid-level expert, and an upcoming junior fellow. There have been a number of recent changes in lithotripter design and techniques. This includes the use of multiple focus machines and improved coupling designs. Additional changes involve better localization real-time monitoring. The main goal of stone treatment today seems to be to get rid of the stone in one session rather than being treated multiple times non-invasively. Stone treatment in the future will be individualized by genetic screening of stone formers, using improved SWL devices for small stones only. However, there is still no consensus about the design of the ideal lithotripter. Innovative concepts such as emergency SWL for ureteric stones may be implemented in clinical routine. PMID:24497687

  14. The Efficacy and Safety of Extracorporeal Shock Wave Lithotripsy in Children

    PubMed Central

    Aksoy, Yılmaz; Yapanoğlu, Turgut; Özbey, İsa

    2009-01-01

    Technological advances in the design of shock wave lithotriptors have precipitated important changes in the management of urolithiasis in children. New generation lithotriptors have reduced the need for anesthesia, lowered hospitalization duration, and resulted in better fluoroscopic targeting reducing radiation exposure. Currently, shock wave lithotripsy (SWL) has become standard first line treatment for most renal and ureteral calculi in children. Herein, the literature and assess success rates, re-treatment rates, preoperative stenting, anesthesia requirements, side effects, and complications of SWL were reviewed. As a result, we aimed to demonstrate that SWL is safe for the treatment of pediatric urolithiasis. PMID:25610082

  15. The Acute and Long-Term Adverse Effects of Shock Wave Lithotripsy

    PubMed Central

    McAteer, James A.; Evan, Andrew P.

    2009-01-01

    Shock wave lithotripsy (SWL) has proven to be a highly effective treatment for the removal of kidney stones. Shock waves (SW’s) can be used to break most stone types, and because lithotripsy is the only non-invasive treatment for urinary stones SWL is particularly attractive. On the downside SWL can cause vascular trauma to the kidney and surrounding organs. This acute SW damage can be severe, can lead to scarring with a permanent loss of functional renal volume, and has been linked to potentially serious long-term adverse effects. A recent retrospective study linking lithotripsy to the development of diabetes mellitus has further focused attention on the possibility that SWL may lead to life-altering chronic effects 1. Thus, it appears that what was once considered to be an entirely safe means to eliminate renal stones can elicit potentially severe unintended consequences. The purpose of this review is to put these findings in perspective. The goal is to explain the factors that influence the severity of SWL injury, update current understanding of the long-term consequences of SW damage, describe the physical mechanisms thought to cause SWL injury, and introduce treatment protocols to improve stone breakage and reduce tissue damage. PMID:18359401

  16. Shock Wave Injury to the Kidney in SWL: Review and Perspective

    NASA Astrophysics Data System (ADS)

    McAteer, James A.; Evan, Andrew P.; Willis, Lynn R.; Connors, Bret A.; Williams, James C.; Pishchalnikov, Yuri A.; Lingeman, James E.

    2007-04-01

    Shock wave lithotripsy (SWL) is a first-line option for treatment for urinary calculi—particularly effective for the removal of uncomplicated stones from the upper urinary tract. The success of lithotripsy is tempered, however, by the occurrence of acute injury that has been reported to progress to long-term complications. SW trauma to the kidney is a vascular lesion characterized by parenchymal and subcapsular bleeding. The acute lesion is dose-dependent, and typically localized to the focal volume of the lithotripter. Cavitation has been implicated in vessel rupture, but SW-shear has the potential to be a primary mechanism for damage as well. Possible chronic adverse effects of SWL may include new-onset hypertension, development of diabetes, and exacerbation of stone disease. If acute trauma could be reduced, it seems likely that serious long-term effects could be minimized, or even eliminated. Reducing the dose of SW's needed for stone breakage is one option. Improved coupling improves stone breakage, and slowing SW rate significantly improves stone-free outcomes. Experiments with animals now show that treatment protocols can be designed to protect against tissue injury. Initiating treatment with low energy SW's dramatically reduces lesion size, and reducing the rate of SW delivery virtually eliminates SW trauma altogether. SWL stands to gain from new advances in technology, as lithotripters become safer and more effective. Perhaps the greatest progress will be made when we have determined the physical mechanisms of SW action both for stone breakage and tissue damage, and have better characterized the biological response to SW's—as this will provide the principles needed to achieve the best combination of safety and efficiency with whatever lithotripter is at hand.

  17. SHOCK WAVE LITHOTRIPSY AND DIABETES MELLITUS: A POPULATION-BASED COHORT STUDY

    PubMed Central

    de Cógáin, Mitra; Krambeck, Amy E.; Rule, Andrew D.; Li, Xujian; Bergstralh, Eric J.; Gettman, Matthew T.; Lieske, John C.

    2011-01-01

    OBJECTIVES The pancreas is vulnerable to injury at the time of shock wave lithotripsy (SWL) as evidenced by case studies; thus, concern exists for the development of diabetes mellitus following SWL. Since previous studies may have been limited by referral and detection biases, the current study was completed in a population-based cohort. METHODS The Rochester Epidemiologic Project (REP) was used to identify all Olmsted County, Minnesota residents diagnosed with urolithiasis from 1985 to 2008. New onset diabetes was identified by diagnostic codes and treatment with SWL by surgical codes. Cox proportional hazards models were used to determine the risk of diabetes following SWL therapy. RESULTS There were 5,287 incident stone formers without pre-existing diabetes and with at least 3 months of follow-up. After an average follow-up of 8.7 years, 423 patients (8%) were treated with SWL and new onset diabetes developed in 743 (12%). The diagnosis of diabetes followed SWL in 77 patients. However, there was no evident association between SWL and the development of diabetes before (HR=0.98, 95% CI: 0.76 to 1.26) or after (HR 0.92, 95% CI: 0.71 to 1.18) controlling for age, gender, and obesity. CONCLUSION In this large, population-based cohort, the long-term risk for developing diabetes was not increased in persons who received SWL to treat their kidney stones. PMID:22088569

  18. Modification of the edge wave in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Zhou, Yufeng

    2012-10-01

    To reduce the bubble cavitation and the consequent vascular injury of shock wave lithotripsy (SWL), a new method was devised to modify the diffraction wave generated at the aperture of a Dornier HM-3 lithotripter. Subsequently, the duration of the tensile wave was shortened significantly (3.2±0.54 μs vs. 5.83±0.56 μs). However, the amplitude and duration of the compressive wave of LSW between these two groups as well as the -6 dB beam width and the amplitude of the tensile wave are almost unchanged. The suppression on bubble cavitation was confirmed using the passive cavitation technique. At the lithotripter focus, while 30 shocks can cause rupture of blood vessel phantom using the HM-3 lithotripter at 20 kV; no rupture could be found after 300 shocks with the edge extender. On the other hand, after 200 shocks the HM-3 lithotripter at 20 kV can achieve a stone fragmentation of 50.4±2.0% on plaster-of-Paris stone phantom, which is comparable to that of using the edge extender (46.8±4.1%, p=0.005). Altogether, the modification on the diffraction wave at the lithotripter aperture can significantly reduce the bubble cavitation activities. As a result, potential for vessel rupture in shock wave lithotripsy is expected.

  19. Hepatic haematoma after shockwave lithotripsy for renal stones.

    PubMed

    Ng, Chi-Fai; Law, Vincent T T; Chiu, Peter K F; Tan, Chong-Boon; Man, Chi-Wai; Chu, Peggy S K

    2012-12-01

    Extracorporeal shock wave lithotripsy (SWL) is a non-invasive procedure for urolithiasis. Only a very small portion of patients suffer from post-SWL haematoma and most of them have perinephric haematoma formation. We present two patients who developed subcapsular hepatic haematomas after SWL, followed by a review of the literature on the condition. PMID:22782117

  20. 3D dynamic simulation of crack propagation in extracorporeal shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Wijerathne, M. L. L.; Hori, Muneo; Sakaguchi, Hide; Oguni, Kenji

    2010-06-01

    Some experimental observations of Shock Wave Lithotripsy(SWL), which include 3D dynamic crack propagation, are simulated with the aim of reproducing fragmentation of kidney stones with SWL. Extracorporeal shock wave lithotripsy (ESWL) is the fragmentation of kidney stones by focusing an ultrasonic pressure pulse onto the stones. 3D models with fine discretization are used to accurately capture the high amplitude shear shock waves. For solving the resulting large scale dynamic crack propagation problem, PDS-FEM is used; it provides numerically efficient failure treatments. With a distributed memory parallel code of PDS-FEM, experimentally observed 3D photoelastic images of transient stress waves and crack patterns in cylindrical samples are successfully reproduced. The numerical crack patterns are in good agreement with the experimental ones, quantitatively. The results shows that the high amplitude shear waves induced in solid, by the lithotriptor generated shock wave, play a dominant role in stone fragmentation.

  1. A Rare Complication of Extracorporeal Shock Wave Lithotripsy: Intrarenal Hematoma Mimicking Pelvis Renalis Tumor.

    PubMed

    Akbulut, Fatih; Kucuktopcu, Onur; Ucpinar, Burak; Savun, Metin; Ozgor, Faruk; Sonmezay, Erkan; Simsek, Abdulmuttalip; Gurbuz, Gokhan

    2015-01-01

    Extracorporeal shock wave lithotripsy (SWL) is a very commonly used treatment modality for appropriate sized stones. Even though it is a noninvasive treatment technique, major complications may occur following SWL sessions. Herein, we report a 17-year-old male patient, who received 2 sessions of SWL treatment for his left kidney stone, 4 months before his admission. Imaging methods showed an enhanced left renal pelvis mass with contrast-enhanced computerized tomography (CT) and this finding raised a suspicion of pelvis renalis tumor. Diagnostic ureterorenoscopy was planned for the patient and operation revealed a left intrarenal hematoma, which was drained percutaneously during the same operation. Careful history should be taken from patients with renal pelvis masses and intrarenal hematoma formation should be kept in mind, especially if the patient has a previous SWL history. PMID:26064767

  2. A Rare Complication of Extracorporeal Shock Wave Lithotripsy: Intrarenal Hematoma Mimicking Pelvis Renalis Tumor

    PubMed Central

    Akbulut, Fatih; Kucuktopcu, Onur; Ucpinar, Burak; Savun, Metin; Ozgor, Faruk; Sonmezay, Erkan; Simsek, Abdulmuttalip; Gurbuz, Gokhan

    2015-01-01

    Extracorporeal shock wave lithotripsy (SWL) is a very commonly used treatment modality for appropriate sized stones. Even though it is a noninvasive treatment technique, major complications may occur following SWL sessions. Herein, we report a 17-year-old male patient, who received 2 sessions of SWL treatment for his left kidney stone, 4 months before his admission. Imaging methods showed an enhanced left renal pelvis mass with contrast-enhanced computerized tomography (CT) and this finding raised a suspicion of pelvis renalis tumor. Diagnostic ureterorenoscopy was planned for the patient and operation revealed a left intrarenal hematoma, which was drained percutaneously during the same operation. Careful history should be taken from patients with renal pelvis masses and intrarenal hematoma formation should be kept in mind, especially if the patient has a previous SWL history. PMID:26064767

  3. Modified shock waves for extracorporeal shock wave lithotripsy: a simulation based on the Gilmore formulation.

    PubMed

    Canseco, Guillermo; de Icaza-Herrera, Miguel; Fernández, Francisco; Loske, Achim M

    2011-10-01

    Extracorporeal shock wave lithotripsy (SWL) is a reliable therapy for the treatment of urolithiasis. Nevertheless, improvements to enhance stone fragmentation and reduce tissue damage are still needed. During SWL, cavitation is one of the most important stone fragmentation mechanisms. Bubbles with a diameter between about 7 and 55μm have been reported to expand and collapse after shock wave passage, forming liquid microjets at velocities of up to 400m/s that contribute to the pulverization of renal calculi. Several authors have reported that the fragmentation efficiency may be improved by using tandem shock waves. Tandem SWL is based on the fact that the collapse of a bubble can be intensified if a second shock wave arrives tenths or even a few hundredths of microseconds before its collapse. The object of this study is to determine if tandem pulses consisting of a conventional shock wave (estimated rise time between 1 and 20ns), followed by a slower second pressure profile (0.8μs rise time), have advantages over conventional tandem SWL. The Gilmore equation was used to simulate the influence of the modified pressure field on the dynamics of a single bubble immersed in water and compare the results with the behavior of the same bubble subjected to tandem shock waves. The influence of the delay between pulses on the dynamics of the collapsing bubble was also studied for both conventional and modified tandem waves. For a bubble of 0.07mm, our results indicate that the modified pressure profile enhances cavitation compared to conventional tandem waves at a wide range of delays (10-280μs). According to this, the proposed pressure profile could be more efficient for SWL than conventional tandem shock waves. Similar results were obtained for a ten times smaller bubble. PMID:21459398

  4. Urine cytology to evaluate urinary urothelial damage of shock-wave lithotripsy.

    PubMed

    Mustafa, Mahmoud; Pancaroglu, Kuddusi

    2011-06-01

    Our aim is to study the prospective trial where urine cytology was used to detect the acute urothelial mucosal damage in patients who undergo extracorporeal shock waves lithotripsy (SWL). The study included 48 consecutive patients (28 male, 20 female) with mean age of 49.02 years (range 18-66) who were treated with SWL due to renal stones (30 patients) or upper ureter stones (18 patients). The mean calculi diameter was 12.44 mm (range 5-20). Urinary cytologic examinations were done for all patients immediately before and after SWL therapy and 10 days latter. The average numbers of transitional cells, red blood cells and myocytes were counted under 40 × magnification. In overall patients the average numbers of transitional cells at the cytologic examinations done immediately before and after SWL therapy were 1.6 and 7.53 cell/field, respectively (p = 0.001). The increment in transitional cells at cytologic examination after SWL was significantly influenced only by number of shock waves applied (p = 0.003). No muscle cell was detected in all cytologic examinations. The cytologic examinations which were done after 10 days of SWL therapy showed recovery from all cytologic abnormalities. The acute increment in number of transitional cells after the SWL is not clinically important and it is a temporary change. Urothelial lesion is limited to mucosal layer and there is no evidence of damage to basal membrane or deeper muscle layer. SWL safety on urothelial and muscular layer was demonstrated. However, evaluation of larger series with use of other lithotripters is necessary before reaching any definitive conclusions. PMID:21063696

  5. Shock Wave Lithotripsy Does Not Impair Renal Function in a Swine Model of Metabolic Syndrome

    PubMed Central

    Johnson, Cynthia D.; Connors, Bret A.; Evan, Andrew P.; Phillips, Carrie L.; Liu, Ziyue

    2015-01-01

    Abstract Purpose: To determine whether shock wave lithotripsy (SWL) may be a risk factor for renal functional impairment in a swine model of metabolic syndrome (MetS). Materials and Methods: 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. Results: 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. Conclusions: Our results are consistent with the view that a single SWL session does not result in renal impairment, even in the presence of MetS. PMID:25285417

  6. Poly(methyl methacrylate) particles for local drug delivery using shock wave lithotripsy: In vitro proof of concept experiment.

    PubMed

    Shaked, Eliav; Shani, Yoav; Zilberman, Meital; Scheinowitz, Mickey

    2015-08-01

    To leverage current local drug delivery systems methodology, there is vast use of polymeric particles serving as drug carriers to assure minimal invasive therapy with little systemic distribution of the released drug. There is an increasing interest in poly(methyl methacrylate) (PMMA) serving as carriers in drug delivery. The study aims to develop PMMA carriers for localized drug delivery and release system, combining innovative biomaterial technology and shock wave lithotripsy (SWL), and to study the effect of SWL on various concentrations of PMMA particles. We prepared PMMA particles that contain horseradish peroxidase (HRP) using a double emulsion technique, and investigated the mechanism of in vitro drug release from the carriers following exposure to SWL. We investigated the correlation between production method modifications, concentrations of the carriers subjected to SWL, and shock wave patterns. We successfully produced PMMA particles as drug carriers and stimulated the release of their contents by SWL; their polymeric shell can be shattered externally by SWL treatment, leading to release of the encapsulated drug. HRP enzyme activity was maintained following the encapsulation process and exposure to high dose of SWL pulses. Increased shock wave number results in increased shattering and greater fragmentation of PMMA particles. The results demonstrate a dose-response release of HRP; quantitation of the encapsulated HRP from the carriers rises with the number of SWL. Moreover, increased concentration of particles subjected to the same dose of SWL results in a significant increase of the total HRP release. Our research offers novel technique and insights into new, site-specific drug delivery and release systems. PMID:25350479

  7. Matched pair analysis of ureteroscopy vs. shock wave lithotripsy for the treatment of upper ureteric calculi.

    PubMed

    Stewart, G D; Bariol, S V; Moussa, S A; Smith, G; Tolley, D A

    2007-05-01

    There is controversy over whether shock wave lithotripsy (SWL) or ureteroscopy (URS) is the best management of ureteric calculi, especially for stones located in the upper ureter. This study compares URS and SWL management of upper ureteric stones directly for the first time using a different analysis tool, the matched pair analysis study design. This method enables meaningful comparisons to be made on a small number of matched patients, using precise like-for-like matching. Adult patients undergoing primary treatment of solitary radiopaque proximal ureteric stones were identified. Patients with stents, nephrostomies or stones at the pelvi-ureteric junction were excluded. Patients had a minimum of 3 months follow-up. Patients treated by primary URS were matched using four parameters (sex, laterality, stone size and location) to patients treated on a Dornier Compact Delta Lithotriptor. A total of 1479 patients had URS or SWL from which 27 upper ureteric stone matched pairs were identified. Three-month stone free rates were 82% for URS and 89% for SWL (McNemar's test, p=0.625). Re-treatment was required in 11% and 26% following URS and SWL respectively (p=0.219). Forty-one per cent of URS patients required an ancillary treatment, such as stent removal, compared with only 22% of SWL patients (p=0.227). Introduction of a holmium:YAG laser for use with URS improved the stone free rate for URS to 100%. Using a robust like-for-like comparison of similar patients with very similar upper ureteric stones the outcomes following SWL and URS were comparable. Choice of treatment should therefore be based on parameters such as availability of equipment, waiting times and patient preference. PMID:17386062

  8. Previous shock-wave lithotripsy treatment does not impact the outcomes of flexible ureterorenoscopy

    PubMed Central

    Yürük, Emrah; Binbay, Murat; Akman, Tolga; Özgör, Faruk; Berberoğlu, Yalçın; Müslümanoğlu, Ahmet Yaser

    2014-01-01

    Objective: Shock-wave lithotripsy (SWL) is the first-line treatment for the active removal of small and medium-sized kidney stones. Flexible ureterorenoscopy (fURS) is recommended after failed SWL treatment. The aim of this retrospective analysis is to evaluate whether prior unsuccessful SWL treatments affect the outcomes of fURS. Material and methods: Data from 206 patients who underwent fURS for the treatment of renal stones between September 2009 and January 2011 were collected, and the patients were divided into two groups according to their previous SWL treatment. The patient demographics, stone characteristics, operation and fluoroscopy times, stone-free rates and complications were compared. Results: Of the patients, 114 (55.3%) did not undergo SWL prior to fURS (Group 1), whereas 92 (44.6%) completed a minimum of 3 sessions of SWL and waited at least 2 weeks before the fURS operation (Group 2). Although the mean stone number was higher in Group 2, this difference was not significant (p=0.06). The mean operation (p=0.12) and fluoroscopy times (p=0.69) were similar between the groups. The mean operation time per mm2 stone and fluoroscopy time per mm2 stone were not significantly different (p=0.64 and p=0.76, respectively). The length of the hospitalization and the overall complication rates were similar. After the third postoperative month, the stone-free rates were not different between the groups (82.5% and 86.9%, respectively, p=0.38). Conclusion: The stone-free and complication rates of fURS were not affected by previous SWL therapy. PMID:26328180

  9. Effect of Different Analgesics on Pain Relief During Extracorporeal Shock Wave Lithotripsy

    PubMed Central

    Yesil, S; Polat, F; Ozturk, U; Dede, O; Imamoglu, MA; Bozkirli, I

    2014-01-01

    Background/aim: The aim of this study was  to compare  three drugs for pain relief during shock wave lithotripsy (SWL). Materials and Methods: Seventy six male patients that were treated for renal stones with SWL were included in this study. They were randomized into four groups. A different treatment protocol was used for each group.  Intramuscular (IM) diclofenac 75mg was given in group 1 (n=20), dexketoprofen, 50mg, IM in group 2 (n=20) and hyoscine 10 mg plus paracetamol 500mg, orally in group 3 (n=20). In group 4 (control, n=16) saline solution   was given 30 min before SWL. Pain during SWL was assessed using the 10-score linear visual analogue pain scale (VAS) and was compared among groups. Age, weight, height, body mass index (BMI), stone size, stone location, duration of SWL, total shock waves performed and mean energy level (kV) for each patient were recorded. A p value of <0.05 was considered statistically significant. Results: The mean patients’ age was 45.4 ± 12.9 years. The highest VAS value was observed in Group 4 (8.4 ± 1), and the lowest  in Group 1 (6.25 ± 2.2).  Statistically significant  difference was noted  only when Group 1 and Group 4 were compared. The remaining groups provided similar results and there were no significant statistical differences according to VAS values. Other parameters were similar  in all groups. Conclusion: In conclusion, this study shows that reducing the pain with a single dose injection of intramuscular diclofenac sodium before SWL is superior compared to others. PMID:25336870

  10. Is flexible ureterorenoscopy and laser lithotripsy the new gold standard for lower pole renal stones when compared to shock wave lithotripsy: Comparative outcomes from a University hospital over similar time period

    PubMed Central

    Burr, Jacob; Ishii, Hiro; Simmonds, Nick

    2015-01-01

    Introduction Renal lower pole stones pose difficulty in management due to anatomical variation, stone size, hardness and patient demographics. Flexible ureterorenoscopy and laser lithotripsy (FURSL) and shock wave lithotripsy (SWL) are preferred for stones 1-2 cm in size. We wanted to compare the outcomes of FURSL and SWL for lower pole stones during the same time period. Material and methods All patients who were treated for lower pole stones with FURSL and SWL during a 19-month period were included. The stone free rate (SFR) was defined as ≤3 mm fragments on follow-up imaging or stone free endoscopically. Data was recorded in an excel spreadsheet with SPSS version 21 used for statistical analysis. Results A total of 161 lower pole procedures were done (93 SWL and 63 FURSL). The mean stone size for SWL (7.4 mm; range: 4-16 mm) was significantly smaller than for FURSL (13.4 mm; 4-53 mm). The mean operating time and hospital stay for FURSL was 65 minutes (range: 30-160 minutes) and 0.5 days (range: 0-7 days) respectively. The SFR was significantly better (p <0.001) for FURSL (n = 63, 93%) compared to SWL (n = 23, 25%). There were 4 (6%) complications (3 Clavien II and 1 Clavien I) in the FURSL group (2 urosepsis, 1 UTI and 1 stent pain). Three patients in the SWL group (Clavien I) were readmitted with renal colic but there were no other complications. Conclusions FURSL for lower pole stones seems to be a much better alternative than SWL with a high SFR even for larger stones and seems to be the new gold standard for lower pole stone management. PMID:26251738

  11. Mechanism by which shock wave lithotripsy can promote formation of human calcium phosphate stones

    PubMed Central

    Evan, Andrew P.; Coe, Fredric L.; Connors, Bret A.; Handa, Rajash K.; Lingeman, James E.

    2015-01-01

    Human stone calcium phosphate (CaP) content correlates with higher urine CaP supersaturation (SS) and urine pH as well as with the number of shock wave lithotripsy (SWL) treatments. SWL does damage medullary collecting ducts and vasa recta, sites for urine pH regulation. We tested the hypothesis that SWL raises urine pH and therefore Cap SS, resulting in CaP nucleation and tubular plugging. The left kidney (T) of nine farm pigs was treated with SWL, and metabolic studies were performed using bilateral ureteral catheters for up to 70 days post-SWL. Some animals were given an NH4Cl load to sort out effects on urine pH of CD injury vs. increased HCO3− delivery. Histopathological studies were performed at the end of the functional studies. The mean pH of the T kidneys exceeded that of the control (C) kidneys by 0.18 units in 14 experiments on 9 pigs. Increased HCO3− delivery to CD is at least partly responsible for the pH difference because NH4Cl acidosis abolished it. The T kidneys excreted more Na, K, HCO3−, water, Ca, Mg, and Cl than C kidneys. A single nephron site that could produce losses of all of these is the thick ascending limb. Extensive injury was noted in medullary thick ascending limbs and collecting ducts. Linear bands showing nephron loss and fibrosis were found in the cortex and extended into the medulla. Thus SWL produces tubule cell injury easily observed histopathologically that leads to functional disturbances across a wide range of electrolyte metabolism including higher than control urine pH. PMID:25656372

  12. Acute pancreatitis and development of pancreatic pseudo cyst after extra corporeal shock wave lithotripsy to a left renal calculus: A rare case with review of literature.

    PubMed

    Mylarappa, Prasad; Javali, Tarun; Prathvi; Ramesh, D

    2014-01-01

    Extracorporeal shock wave lithotripsy (SWL) is considered the standard of care for the treatment of small upper ureteric and renal calculi. A few centers have extended its use to the treatment of bile duct calculi and pancreatic calculi. The complication rates with SWL are low, resulting in its wide spread acceptance and usage. However, some of the serious complications reported in 1% of patients include acute pancreatitis, perirenal hematoma, urosepsis, venous thrombosis, biliary obstruction, bowel perforation, lung injury, rupture of aortic aneurysm and intracranial hemorrhage. To our knowledge, only six cases of acute pancreatitis or necrotizing pancreatitis following SWL have been documented in the literature. Herein, we report a rare case of acute pancreatitis and formation of a pseudo cyst following SWL for left renal pelvic calculus. PMID:24497695

  13. Acute pancreatitis and development of pancreatic pseudo cyst after extra corporeal shock wave lithotripsy to a left renal calculus: A rare case with review of literature

    PubMed Central

    Mylarappa, Prasad; Javali, Tarun; Prathvi; Ramesh, D.

    2014-01-01

    Extracorporeal shock wave lithotripsy (SWL) is considered the standard of care for the treatment of small upper ureteric and renal calculi. A few centers have extended its use to the treatment of bile duct calculi and pancreatic calculi. The complication rates with SWL are low, resulting in its wide spread acceptance and usage. However, some of the serious complications reported in 1% of patients include acute pancreatitis, perirenal hematoma, urosepsis, venous thrombosis, biliary obstruction, bowel perforation, lung injury, rupture of aortic aneurysm and intracranial hemorrhage. To our knowledge, only six cases of acute pancreatitis or necrotizing pancreatitis following SWL have been documented in the literature. Herein, we report a rare case of acute pancreatitis and formation of a pseudo cyst following SWL for left renal pelvic calculus. PMID:24497695

  14. Innovations in Lithotripsy Technology

    NASA Astrophysics Data System (ADS)

    Zhong, Pei

    2007-04-01

    The introduction of shock wave lithotripsy (SWL) in the early 1980's revolutionized the surgical management for kidney stone disease. Since then, although numerous 2nd- and 3rd-generation lithotripters have been developed using various means for shock wave generation, focusing, patient coupling and stone localization, the technical improvements in these devices were largely made based on practical concerns for user convenience and multifunctionality of the system rather than a clear understanding of the working principles of SWL. In this paper, the fundamental mechanisms of stone comminution and tissue injury in SWL revealed by basic studies in the past two decades are first reviewed. This is followed by a summary of the innovations in SWL technology developed in recent years that have been demonstrated to provide improved stone comminution with concomitantly reduced tissue injury both in vitro using phantom systems and in vivo in animal models. Furthermore, the role of treatment strategy in determining the overall outcome of clinical lithotripsy is emphasized, and future prospects for lithotripsy research and technological innovations are discussed.

  15. Complications of extracorporeal shock wave lithotripsy for urinary stones: to know and to manage them-a review.

    PubMed

    D'Addessi, Alessandro; Vittori, Matteo; Racioppi, Marco; Pinto, Francesco; Sacco, Emilio; Bassi, PierFrancesco

    2012-01-01

    To identify the possible complications after extracorporeal shock wave lithotripsy (SWL) and to suggest how to manage them, the significant literature concerning SWL treatment and complications was analyzed and reviewed. Complications after SWL are mainly connected to the formation and passage of fragments, infections, the effects on renal and nonrenal tissues, and the effects on kidney function. Each of these complications can be prevented adopting appropriate measures, such as the respect of the contraindications and the recognition and the correction of concomitant diseases or infection, and using the SWL in the most efficient and safe way, tailoring the treatment to the single case. In conclusion, SWL is an efficient and relatively noninvasive treatment for urinary stones. However, as with any other type of therapy, some contraindications and potential complications do exist. The strictness in following the first could really limit the onset and danger of the appearance of others, which however must be fully known so that every possible preventive measure be implemented. PMID:22489195

  16. Complications of Extracorporeal Shock Wave Lithotripsy for Urinary Stones: To Know and to Manage Them—A Review

    PubMed Central

    D'Addessi, Alessandro; Vittori, Matteo; Racioppi, Marco; Pinto, Francesco; Sacco, Emilio; Bassi, PierFrancesco

    2012-01-01

    To identify the possible complications after extracorporeal shock wave lithotripsy (SWL) and to suggest how to manage them, the significant literature concerning SWL treatment and complications was analyzed and reviewed. Complications after SWL are mainly connected to the formation and passage of fragments, infections, the effects on renal and nonrenal tissues, and the effects on kidney function. Each of these complications can be prevented adopting appropriate measures, such as the respect of the contraindications and the recognition and the correction of concomitant diseases or infection, and using the SWL in the most efficient and safe way, tailoring the treatment to the single case. In conclusion, SWL is an efficient and relatively noninvasive treatment for urinary stones. However, as with any other type of therapy, some contraindications and potential complications do exist. The strictness in following the first could really limit the onset and danger of the appearance of others, which however must be fully known so that every possible preventive measure be implemented. PMID:22489195

  17. The Effect of Terpene Combination on Ureter Calculus Expulsion After Extracorporeal Shock Wave Lithotripsy

    PubMed Central

    Kim, Dai Hee; Goh, Hyeok Jun; Lee, Ho Won; Kim, Kyu Shik; Kim, Yong Tae; Moon, Hong Sang; Lee, Seung Wook

    2014-01-01

    Purpose Terpene combination (Rowatinex) is known to help with the expulsion of urinary stones. The aim of this study was to determine how Rowatinex affects the expulsion of remnant stones after shock wave lithotripsy (SWL). Materials and Methods Clinical data were collected retrospectively from 499 patients with a diagnosis of ureteral stones who underwent SWL from January 2009 to August 2012. Ureteral stones were diagnosed in all patients by kidney, ureter, and bladder x-ray and abdominal computed tomography (CT). The progress of patients was documented every 2 weeks to confirm remnant stones after SWL. The patients with remnant stones underwent SWL again. Group 1 consisted of patients who were prescribed an analgesic, Tamsulosin 0.2 mg, and Rowatinex. Group 2 consisted of patients who were prescribed only an analgesic and Tamsulosin 0.2 mg. The expulsion rate of urinary stones was compared between groups. Results The expulsion rate of urinary stones was not significantly different between the two groups after 2 weeks. However, after 4 weeks, group 1 had a significantly higher expulsion rate (72.2% compared with 61.1%, p=0.022). Fifteen patients (10.2%) in group 1 and 40 (11.4%) in group 2 had to undergo ureteroscopic removal of the stone (p=0.756). Acute pyelonephritis occurred in one patient (0.7%) in group 1 and in one patient (0.3%) in group 2 (p=0.503). Conclusions The long-term administration of Rowatinex for 4 weeks increased the expulsion rate of urinary stones after SWL. PMID:24466395

  18. Shock Wave Lithotripsy: Effects on the Pancreas and Recurrent Stone Disease

    NASA Astrophysics Data System (ADS)

    Krambeck, Amy E.; Rohlinger, Audrey L.; Lohse, Christine M.; Patterson, David E.; Gettman, Matthew T.

    2007-04-01

    Long-term effects of shockwave lithotripsy (SWL) are unknown; however, we recently found an association between SWL and diabetes mellitus in a population based case control cohort. To further study the association between SWL and diabetes mellitus, we determined the immediate impact of SWL on the pancreas as well as the long-term natural history of stone disease following treatment. Chart review identified 630 patients treated with SWL at our institution in 1985. Questionnaires focusing on recurrent stone episodes after SWL were sent to 578 patients alive in 2004. To further assess impact of SWL on the pancreas, pancreatic enzyme measurements were performed on 24 symptomatic stone patients treated in 2006 with ureteroscopy (n=12) and SWL (n=12). Serum amylase and lipase were evaluated pre and post SWL. A⩾5 U/L increase in either lab value was considered significant. Among patients in the long-term SWL treatment group, the questionnaire response rate was 58.9% (288/489). Recurrent stone events were noted in 154 (53.5%) of the survey respondents. Characteristics associated with stone recurrences were: gender (p=0.004), age at SWL (p=0.022), BMI (p=0.007), SWL complications (p=0.009), and lower pole SWL (p=0.025). Recurrent stone disease was also associated with the development of diabetes mellitus (p=0.020). In the contemporary group of treated stone patients, pancreatic enzyme analysis demonstrated an increase in serum amylase and lipase in 3 (25.0%) SWL patients and 1 (8.3%) ureteroscopy patient (p=0.273). In conclusion, over half of the patients treated with SWL will develop recurrent stone events. We found a strong association between recurrent stone disease and the development of diabetes mellitus at long-term follow-up. Although not statistically significant due to small number, data in a contemporary treatment cohort suggest the possibility that the pancreas can be adversely affected by SWL.

  19. New-onset diabetes mellitus after shock wave lithotripsy for urinary stone: a systematic review and meta-analysis.

    PubMed

    Deng, Tuo; Liao, Banghua; Tian, Ye; Luo, Deyi; Liu, Jiaming; Jin, Tao; Wang, Kunjie

    2015-06-01

    The purpose of the study was to evaluate the association between shock wave lithotripsy (SWL) for urinary stone and new-onset diabetes mellitus (DM). A comprehensive data collection was performed in the Pubmed database, Embase database, Chinese Biomedical database, Chinese National Knowledge Infrastructure database and VIP database. Difference in incidence of new-onset DM after SWL between cases and controls was evaluated by odds ratio (OR) with its 95% confidence interval (CI). And summary adjusted risk ratios (RRs) and 95% CIs were calculated to assess the strength of association between SWL and new-onset DM, and then subgroup analyses were conducted. Five studies were included in this meta-analysis. The incidence of new-onset DM after SWL is not higher than that in the population who do not receive SWL [OR = 1.59, 95% CI (0.92, 2.74), P = 0.10]. And statistical association between SWL and new-onset DM could not be found significantly [RR = 1.33, 95% CI (0.83, 2.13), P = 0.24], either. However, body mass index (BMI) [RR = 1.09, 95% CI (1.04, 1.14), P < 0.001] and family history of DM (FHx DM) [RR = 0.35, 95% CI (0.15, 0.80), P = 0.013] were found significantly associated with the development of DM in subgroup analyses. Our data suggests that there is no association between SWL for urinary stone and new-onset DM. PMID:25753541

  20. Changes in Urolithiasis Referral Patterns for Shock Wave Lithotripsy over a Decade: Was There Adherence to AUA/EAU Guidelines?

    PubMed Central

    Noureldin, Yasser A.; Elkoushy, Mohamed A.; Andonian, Sero

    2015-01-01

    Objective The primary objective was to assess changes in referral patterns of urolithiasis for shock wave lithotripsy (SWL) over a decade. The secondary objective was to evaluate the effect of the number of years of practice of referring physicians on these referral patterns. Methods A retrospective review of SWL database was performed for consecutive referrals for SWL at a tertiary stone center between December 1999 and December 2013. Patient demographics and stone characteristics were assessed. The stone location at the time of referral was used as the reference. Retreatments were excluded. In addition, years of practice of the referring physicians were calculated. The 2007 AUA/EAU guidelines on urolithiasis were considered as a reference. Results A total of 8,992 SWL treatments were included. After December 2007, there was a significant increase in the percentage of renal pelvic stones referred for SWL (23.0 vs. 27.1%, p < 0.001). Conversely, proximal ureteral stones significantly decreased after 2007 (24 vs. 18.2%, p < 0.001) including stones > 10 mm (5.1 vs. 2.9%, p < 0.001). Otherwise, there were no changes in the referral patterns for SWL of other stone locations before and after December 2007 (p > 0.05). Furthermore, percentage of stones referred for SWL by urologists practicing for less than 10 years significantly decreased after December 2007 (29.5 vs. 22.8%, p < 0.001). Conclusions The significant reduction in the referral of proximal ureteral stones after December 2007 corresponds to the latest AUA/EAU guidelines on management of ureteral stones. PMID:26889134

  1. Optimizing Shock Wave Lithotripsy: A Comprehensive Review

    PubMed Central

    McClain, Paul D; Lange, Jessica N; Assimos, Dean G

    2013-01-01

    Shock wave lithotripsy is a commonly used procedure for eradicating upper urinary tract stones in patients who require treatment. A number of methods have been proposed to improve the results of this procedure, including proper patient selection, modifications in technique, adjunctive therapy to facilitate elimination of fragments, and changes in lithotripter design. This article assesses the utility of these measures through an analysis of contemporary literature. PMID:24082843

  2. SHOCK WAVE LITHOTRIPSY IS NOT PREDICTIVE OF HYPERTENSION AMONG COMMUNITY STONE FORMERS AT LONG-TERM FOLLOW-UP

    PubMed Central

    Krambeck, Amy E.; Rule, Andrew D.; Li, Xujian; Bergstralh, Eric J.; Gettman, Matthew T.; Lieske, John C.

    2011-01-01

    INTRODUCTION Concern exists over the subsequent development of hypertension after use of shock wave lithotripsy (SWL) for the treatment of symptomatic urolithiasis. Referral bias and lack of long-term follow-up has been a limitation of prior studies. METHODS We identified all Olmsted County, Minnesota residents with a diagnosis of urolithiasis from 1985 to 2008. The charts were electronically queried for hypertension and obesity by diagnostic codes and use of SWL by surgical codes. All patients first diagnosed with hypertension before or up to 90 days after their first documented kidney stone were considered to have prevalent hypertension and excluded. Cox proportional hazards models were used to assess the association of SWL with a subsequent diagnosis of hypertension. RESULTS We identified 6,077 incident urolithiasis patients with greater than 90 days follow-up. We excluded 1,295 (21.3%) of the population for prevalent hypertension leaving 4,782 incident urolithiasis patients for analysis. During an average follow-up of 8.7 years, new-onset hypertension was diagnosed in 983 (20.6%) of the cohort at a mean of 6.0 years from index stone date. Only 400 (8.4%) of the cohort received SWL therapy. There was no significant association between SWL treatment and the development of hypertension in univariate (P=0.33) and multivariate modeling controlling for age, gender, and obesity (Hazard ratio [95% CI] =1.03[0.84, 1.27], P=0.77). CONCLUSION In a large population based cohort of kidney stone formers, we failed to identify an association between SWL and the subsequent long-term risk of hypertension. PMID:21074794

  3. Prospective randomized trial comparing shock wave lithotripsy and flexible ureterorenoscopy for lower pole stones smaller than 1 cm.

    PubMed

    Sener, Nevzat Can; Imamoglu, M Abdurrahim; Bas, Okan; Ozturk, Ufuk; Goktug, H N Goksel; Tuygun, Can; Bakirtas, Hasan

    2014-04-01

    In this study, we aimed to compare the success and complications of flexible ureterorenoscopy (F-URS) with its advanced technology and the accomplished method of shock wave lithotripsy (SWL) in the treatment of lower pole stones smaller than 1 cm. One hundred and forty patients were randomized as 70 undergoing SWL (Group 1) and 70 undergoing F-URS (Group 2). Patients were evaluated by plain X-ray and urinary ultrasound 1 week and after 3 months following SWL. The same procedure was done for F-URS patients 1 week after surgery and after 3 months. Success rates were established the day following the procedure and after 3 months. Fragmentation less than 3 mm was considered success. Mean operative time was 44 ± 7.4 min for Group 2 and mean fluoroscopy duration was 51 ± 12 s. In F-URS group, all the patients were stone free after 3 months (100 %). Group 1 had 2.7 ± 0.4 sessions of SWL. Sixty-four patients were stone free in that group after 3 months (91.5 %). The procedure yielded significant success in FURS group, even though patients underwent SWL for 2.7 ± 0.4 sessions and F-URS for 1 session (p < 0.05). With higher success and similar complication rates, fewer sessions per treatment, and advances in technology and experience, we believe F-URS has a potential to be the first treatment option over SWL in the future. PMID:24220692

  4. Is shock wave lithotripsy efficient for the elderly stone formers? Results of a matched-pair analysis.

    PubMed

    Philippou, Prodromos; Lamrani, Djelali; Moraitis, Konstantinos; Bach, Christian; Masood, Junaid; Buchholz, Noor

    2012-08-01

    The aim of the study was to evaluate the impact of age on the efficacy of extracorporeal shock wave lithotripsy (SWL), in a comparative study based on the principles of matched-pair analysis. Over a period of 4 years, 2,311 patients were treated with SWL in a tertiary referral center. Patient and stone data were recorded in a prospective electronic database. Among these patients, 115 (4.97%) were older than 70 years of age and fulfilled the criteria for inclusion in the study (Group A). For the purposes of the comparative analysis, Group A patients were matched for gender and stone parameters (side, location of stone, and diameter ±2 mm) with a control group of patients under the age of 70 (Group B). Following matching, the patients' electronic medical records were reviewed, to identify SWL success rates at 3 months and McNemar's test was used to compare the efficacy of SWL between the two groups. Matching was possible in all cases. The results indicate that there were no statistically significant differences in the mean number of SWL sessions or in the mean number of impulses per session between the two groups. The overall stone clearance rate achieved by SWL alone was 71.3% for Group A and 73.9% for group B. Discordant pairs were found in 37 cases (in 17 pairs only patients in Group A became stone-free, while in 20 pairs only patients in Group B became stone-free). By using McNemar's test, the difference in stone clearance rates between the two groups was not found to be statistically significant (p = 0.742). A total of 22 patients (19.1%) in Group A and 17 patients (14.7%) in Group B underwent an adjuvant procedure to achieve stone clearance. McNemar's test also revealed the absence of any statistically significant difference in SWL success rates between older and younger patients in the subgroups of patients presenting with either ureteric or renal stones (p = 0.727 and p = 0.571, respectively). In conclusion, SWL is still considered one of the first-line tools for geriatric patients suffering from urolithiasis, as increased age alone does not seem to adversely affect the efficacy of SWL. PMID:21901557

  5. Ureteroscopy in proximal ureteral stones after shock wave lithotripsy failure: Is it safe and efficient or dangerous?

    PubMed Central

    Kilinc, Muhammet Fatih; Doluoglu, Omer Gokhan; Karakan, Tolga; Dalkilic, Ayhan; Sonmez, Nurettin Cem; Aydogmus, Yasin; Resorlu, Berkan

    2015-01-01

    Introduction: We assessed the effectiveness of ureteroscopy (URS) in proximal ureteral stones performed after shock wave lithotripsy (SWL) failure, and determined outcomes in terms of success rate, complications, and operation time. Methods: We analyzed data of patients with previous unsuccessful SWL (Group I) and the ones that did not have SWL or URS before (Group II) for proximal ureteral stones between December 2007 and August 2014. Group I included 346 patients who underwent complementary URS and Group II 209 patients who underwent primary URS. Success rates, operation time and complications were compared between groups. Results: Success rates of complementary and primary URS were 78.9% and 80.9%, respectively. The difference in success rates was not statistically significant between groups (p = 0.57). The complication rates of complementary URS was 12.1%, and 9.5% in primary URS (p = 0.49). No statistically significant differences were noted in terms of gender, age, stone size and side, or lithotripter type between groups. The mean operation time and need for balloon dilatation were higher in complementary URS group compared to the primary URS group, and the difference was statistically significant (p < 0.05). Conclusions: Complementary URS may be used safely after SWL failure in proximal ureteral stones. Its success rate and morbidities are similar to primary URS, except for longer operation time and an increased need for balloon dilatation. PMID:26664506

  6. Shock-wave lithotripsy in the elderly: Safety, efficacy and special considerations

    PubMed Central

    Philippou, Prodromos; Lamrani, D.; Moraitis, Konstantinos; Wazait, Hassan; Masood, Junaid; Buchholz, Noor

    2011-01-01

    Purpose Shock-wave lithotripsy (SWL) for elderly patients can be challenging. Patients often have a long-standing complex stone burden and significant comorbidities. We report a cohort of patients aged ⩾70 years who were treated by SWL, with special attention to treatment outcomes, complications and the need for adjuvant procedures. Patients and methods Over a period of 4 years, 2311 patients were treated with SWL in a tertiary referral centre. Among these patients, 137 were aged ⩾70 years (5.9%). Patient and stone data were obtained from an electronic database and the patients’ electronic medical records were reviewed. Results During the pre-procedural assessment, 29 patients (21.2%) were considered to be at high anaesthetic risk, due their comorbidities (American Society of Anesthesiology score 3+). In terms of stone burden, 16 stones (11.7%) were located in the distal ureter (mean stone diameter 7.9 mm) and 28 (20.4%) were in the proximal ureter (mean diameter 10.1 mm). In the kidney, 54 stones (39.4%) were in the renal pelvis, upper or mid calyx (mean diameter 10.6 mm), while 39 stones (28.5%) were in the lower calyx (mean diameter 10.1 mm). The median (range) number of SWL sessions per patient was 2.0 (1–3). The overall stone-free rate achieved by SWL alone was 63.5% (65.9% for ureteric stones and 62.4% for renal stones). In total, 38 patients (27.7%) had an adjuvant procedure to achieve stone clearance (ureteroscopy in 23, PCNL in 14 and laparoscopic ureterolithotomy in one case). Apart from six cases (4.3%) of ureteric obstruction due to steinstrasse, there were no severe complications noted. Conclusions The management of elderly patients presenting with urolithiasis is challenging, due to the presence of significant comorbidities. Careful assessment of an integrated management plan for geriatric patients with urolithiasis is essential, and SWL still remains a safe and efficient first-line tool in well-selected cases. PMID:26579264

  7. Lithotripsy

    MedlinePlus

    ... pass through your body until they hit the kidney stones. If you are awake, you may feel a ... Lithotripsy is used to remove kidney stones that are causing: Bleeding ... Not all kidney stones can be removed using lithotripsy. ...

  8. Clinical Nomograms to Predict Stone-Free Rates after Shock-Wave Lithotripsy: Development and Internal-Validation

    PubMed Central

    Kim, Jung Kwon; Ha, Seung Beom; Jeon, Chan Hoo; Oh, Jong Jin; Cho, Sung Yong; Oh, Seung-June; Kim, Hyeon Hoe; Jeong, Chang Wook

    2016-01-01

    Purpose Shock-wave lithotripsy (SWL) is accepted as the first line treatment modality for uncomplicated upper urinary tract stones; however, validated prediction models with regards to stone-free rates (SFRs) are still needed. We aimed to develop nomograms predicting SFRs after the first and within the third session of SWL. Computed tomography (CT) information was also modeled for constructing nomograms. Materials and Methods From March 2006 to December 2013, 3028 patients were treated with SWL for ureter and renal stones at our three tertiary institutions. Four cohorts were constructed: Total-development, Total-validation, CT-development, and CT-validation cohorts. The nomograms were developed using multivariate logistic regression models with selected significant variables in a univariate logistic regression model. A C-index was used to assess the discrimination accuracy of nomograms and calibration plots were used to analyze the consistency of prediction. Results The SFR, after the first and within the third session, was 48.3% and 68.8%, respectively. Significant variables were sex, stone location, stone number, and maximal stone diameter in the Total-development cohort, and mean Hounsfield unit (HU) and grade of hydronephrosis (HN) were additional parameters in the CT-development cohort. The C-indices were 0.712 and 0.723 for after the first and within the third session of SWL in the Total-development cohort, and 0.755 and 0.756, in the CT-development cohort, respectively. The calibration plots showed good correspondences. Conclusions We constructed and validated nomograms to predict SFR after SWL. To the best of our knowledge, these are the first graphical nomograms to be modeled with CT information. These may be useful for patient counseling and treatment decision-making. PMID:26890006

  9. Extracorporeal shock wave lithotripsy: What is new?

    PubMed Central

    Bach, Christian; Karaolides, Theocharis; Buchholz, Noor

    2012-01-01

    Objectives Thirty years after its introduction, extracorporeal shockwave lithotripsy (ESWL) is still first-line treatment for more than half of all urinary tract stones, but machines and treatment strategies have significantly developed over time. In this review, we summarise the latest knowledge about the clinically important aspects of ESWL. Methods We searched PubMed to identify relevant reports and the latest European Association of Urology guidelines, and standard urological textbooks were consulted. Results New technical developments include: Twin-head and tandem-pulse shock-wave generators; wide-focus, low-pressure systems; optimised coupling; and automated location and acoustic tracking systems. Indications have been refined, making possible the identification of patients in whom ESWL treatment is likely to fail. By lowering the shock-wave rate, improving coupling, applying abdominal compression, power ‘ramping’ and postoperative medical expulsion therapy, treatment protocols have been optimised. Conclusions Promising new technical developments are under development, with the potential to increase the stone-free rate after ESWL. For optimal results, the refined indications need to be respected and optimised treatment protocols should be applied. PMID:26558039

  10. Is scoring system of computed tomography based metric parameters can accurately predicts shock wave lithotripsy stone-free rates and aid in the development of treatment strategies?

    PubMed Central

    Badran, Yasser Ali; Abdelaziz, Alsayed Saad; Shehab, Mohamed Ahmed; Mohamed, Hazem Abdelsabour Dief; Emara, Absel-Aziz Ali; Elnabtity, Ali Mohamed Ali; Ghanem, Maged Mohammed; ELHelaly, Hesham Abdel Azim

    2016-01-01

    Objective: The objective was to determine the predicting success of shock wave lithotripsy (SWL) using a combination of computed tomography based metric parameters to improve the treatment plan. Patients and Methods: Consecutive 180 patients with symptomatic upper urinary tract calculi 20 mm or less were enrolled in our study underwent extracorporeal SWL were divided into two main groups, according to the stone size, Group A (92 patients with stone ≤10 mm) and Group B (88 patients with stone >10 mm). Both groups were evaluated, according to the skin to stone distance (SSD) and Hounsfield units (≤500, 500–1000 and >1000 HU). Results: Both groups were comparable in baseline data and stone characteristics. About 92.3% of Group A rendered stone-free, whereas 77.2% were stone-free in Group B (P = 0.001). Furthermore, in both group SWL success rates was a significantly higher for stones with lower attenuation <830 HU than with stones >830 HU (P < 0.034). SSD were statistically differences in SWL outcome (P < 0.02). Simultaneous consideration of three parameters stone size, stone attenuation value, and SSD; we found that stone-free rate (SFR) was 100% for stone attenuation value <830 HU for stone <10 mm or >10 mm but total number SWL sessions and shock waves required for the larger stone group were higher than in the smaller group (P < 0.01). Furthermore, SFR was 83.3% and 37.5% for stone <10 mm, mean HU >830, SSD 90 mm and SSD >120 mm, respectively. On the other hand, SFR was 52.6% and 28.57% for stone >10 mm, mean HU >830, SSD <90 mm and SSD >120 mm, respectively. Conclusion: Stone size, stone density (HU), and SSD is simple to calculate and can be reported by radiologists to applying combined score help to augment predictive power of SWL, reduce cost, and improving of treatment strategies. PMID:27141192

  11. Drugs for Pain Management in Shock Wave Lithotripsy

    PubMed Central

    Bach, Christian; Zaman, Faruquz; Kachrilas, Stefanos; Kumar, Priyadarshi; Buchholz, Noor; Masood, Junaid

    2011-01-01

    Objective. With this review, we provide a comprehensive overview of the main aspects and currently used drugs for analgesia in shockwave lithotripsy. Evidence Acquisition. We reviewed current literature, concentrating on newer articles and high-quality reviews in international journals. Results. No standardized protocols for pain control in SWL exist, although it is crucial for treatment outcome. General and spinal anaesthesia show excellent pain control but are only recommended for selected cases. The newer opioids and nonsteroidal anti-inflammatory drugs are able to deliver good analgesia. Interest in inhalation anaesthesia with nitrous oxide, local anaesthesia with deep infiltration of the tissue, and dermal anaesthesia with EMLA or DMSO has recently rekindled, showing good results in terms of pain control and a favourable side effect profile. Tamsulosin and paracetamol are further well-known drugs being currently investigated. Conclusion. Apart from classically used drugs like opioids and NSARs, medicaments like nitrous oxide, paracetamol, DMSA, or refined administration techniques for infiltration anaesthesia show a good effectiveness in pain control for SWL. PMID:22135735

  12. Predictive value of low tube voltage and dual-energy CT for successful shock wave lithotripsy: an in vitro study.

    PubMed

    Largo, Remo; Stolzmann, Paul; Fankhauser, Christian D; Poyet, Cédric; Wolfsgruber, Pirmin; Sulser, Tullio; Alkadhi, Hatem; Winklhofer, Sebastian

    2016-06-01

    This study investigates the capabilities of low tube voltage computed tomography (CT) and dual-energy CT (DECT) for predicting successful shock wave lithotripsy (SWL) of urinary stones in vitro. A total of 33 urinary calculi (six different chemical compositions; mean size 6 ± 3 mm) were scanned using a dual-source CT machine with single- (120 kVp) and dual-energy settings (80/150, 100/150 Sn kVp) resulting in six different datasets. The attenuation (Hounsfield Units) of calculi was measured on single-energy CT images and the dual-energy indices (DEIs) were calculated from DECT acquisitions. Calculi underwent SWL and the number of shock waves for successful disintegration was recorded. The prediction of required shock waves regarding stone attenuation/DEI was calculated using regression analysis (adjusted for stone size and composition) and the correlation between CT attenuation/DEI and the number of shock waves was assessed for all datasets. The median number of shock waves for successful stone disintegration was 72 (interquartile range 30-361). CT attenuation/DEI of stones was a significant, independent predictor (P < 0.01) for the number of required shock waves with the best prediction at 80 kVp (β estimate 0.576) (P < 0.05). Correlation coefficients between attenuation/DEI and the number of required shock waves ranged between ρ = 0.31 and 0.68 showing the best correlation at 80 kVp (P < 0.001). The attenuation of urinary stones at low tube voltage CT is the best predictor for successful stone disintegration, being independent of stone composition and size. DECT shows no added value for predicting the success of SWL. PMID:26391614

  13. Diuresis and inversion therapy to improve clearance of lower caliceal stones after shock wave lithotripsy: A prospective, randomized, controlled, clinical study

    PubMed Central

    Ahmed, Abul-fotouh; Shalaby, Essam; Maarouf, Aref; Badran, Yasser; Eladl, Mahmoud; Ghobish, Ammar

    2015-01-01

    Objective: To improve the clearance of lower caliceal stones (LCSs) after shock wave lithotripsy (SWL) using a combination of intra-operative forced diuresis and inversion therapy. Materials and Methods: One hundred and fifty-seven consecutive patients with symptomatic, single LCSs of 5–20 mm size were prospectively randomized into two groups. The first (study group, SG) underwent SWL at the time of the maximum diuresis with the patient in the Trendelenburg position with an angle of 30 degree, while the second group (control group, CG) underwent standard SWL. After the last SWL session, patients were followed-up regularly using plain abdominal X-ray and renal ultrasound. The primary endpoint of the study was the stone-free rate (SFR) at 12 weeks. Results: A total of 141 patients completed the study treatment protocol and follow-up: 69 patients in SG and 72 patients in CG. Both groups were comparable in baseline data. SG showed significantly higher SFR at all follow-up time points. At week 12, 78.3% of SG were rendered stone free, whereas only 61.1% were stone free in CG (P = 0.030). Also, there was a significantly higher SFR for larger stones (>10 mm) and stones with higher attenuation value (>500 Hounsfield units) in SG than CG. Mild non-significant complications were reported in both groups. Conclusion: SWL with intraoperative forced diuresis and inversion seems to be an effective measure with minimal extra cost to improve LCS clearance post-SWL. PMID:25878414

  14. Extracorporeal shock-wave lithotripsy. Initial Australian experience.

    PubMed

    Brooks, A J; Drummond, J M; Collison, J M

    1987-04-20

    Fifty patients were treated with extracorporeal shock-wave lithotripsy for upper urinary tract calculi. The procedure was performed by means of either epidural or general anaesthesia. There were minimal postoperative complications with a mean length of stay of 3.6 days. Six patients required a repeat extracorporeal shock-wave lithotripsy procedure for residual fragments during their initial admission to hospital. Forty (80%) patients were free of all stone fragments within one month of their discharge from hospital. Three patients have residual fragments of greater than 2 mm in axial length. The remainder underwent other procedures to remove residual stones or will be treated with further extracorporeal shock-wave lithotripsy therapy. PMID:3614054

  15. Ureteral stenting during extracorporeal shock wave lithotripsy: help or hindrance?

    PubMed

    Preminger, G M; Kettelhut, M C; Elkins, S L; Seger, J; Fetner, C D

    1989-07-01

    We retrospectively reviewed the outcome of extracorporeal shock wave lithotripsy in patients with renal calculi less than 3 cm. in size who were treated at a large multi-user lithotripsy center. Patients in whom indwelling ureteral stents were placed before lithotripsy treatment were subjected to higher levels of total power (shocks times voltage), yet the rate free of stones did not differ from those treated without a stent. In addition, the patients with internal ureteral stents experienced a significantly higher incidence of urinary urgency (43 versus 25 per cent) and hematuria (40 versus 23 per cent) than nonstented patients, respectively (p less than 0.05). Also, the duration of bladder discomfort was longer for stented patients (26 versus 13 per cent) as was the duration of urinary frequency (31 versus 16 per cent), compared to nonstented patients (p less than 0.05). The results suggest that use of an indwelling ureteral stent may not contribute to a higher rate free of stones for the treatment of small to medium sized renal calculi and, in fact, it may make the treatment more uncomfortable for the patient than performing lithotripsy without ureteral stenting. Of course, in selected cases (solitary kidney, large stone burden and aid in stone localization) ureteral stenting has a useful adjunctive role in extracorporeal shock wave lithotripsy. PMID:2733104

  16. Perspective on Lithotripsy Adverse Effects

    NASA Astrophysics Data System (ADS)

    Knoll, Thomas; Wendt-Nordahl, Gunnar

    2008-09-01

    Shock wave lithotripsy (SWL) is an effective and without any doubt the least invasive procedure to treat upper urinary tract calculi. Acute complications are rarely reported and do not require specific treatment in most cases. However, one should be aware that energy levels sufficient for stone breakage are capable of damaging tissue as well, and significant hematoma—not only in the kidney but as well in surrounding organs—has been observed. Furthermore, only little is known about the long-term effects of SWL. Some authors have reported an increased incidence of hypertension and possibly also diabetes mellitus. Such chronic diseases—if indeed related to prior SWL—may be a late result of acute SWL-related trauma but the discussion on the underlying pathogenesis is controversial. Many factors have to be considered, such as the natural history of recurrent stone formers, technical principles of SWL, and differences in treatment protocols. Promising studies are currently underway to optimize stone breakage while limiting potential collateral damage. With this progress, SWL remains a safe treatment option for most urinary calculi.

  17. Optimization of pressure waveform, distribution and sequence in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Zhou, Yufeng

    This work aims to improve shock wave lithotripsy (SWL) technology by increasing stone comminution efficiency while reducing simultaneously the propensity of tissue injury. First, the mechanism of vascular injury in SWL was investigated. Based on in vitro vessel phantom experiment and theoretical calculation, it was found that SWL-induced large intraluminal bubble expansion may constitute a primary mechanism for the rupture of capillaries and small blood vessels. However, when the large intraluminal bubble expansion is suppressed by inversion of the pressure waveform of the lithotripter shock wave (LSW), rupture of a 200-mum cellulose hollow fiber vessel phantom can be avoided. Based on these experimental observations and theoretical assessment of bubble dynamics using the Gilmore model an in situ pulse superposition technique was developed to reduce tissue injury without compromising stone comminution in SWL. A thin shell ellipsoidal reflector insert was fabricated to fit snugly with the original HM-3 reflector. Using the Hamilton model, the effects of reflector geometry on the pulse profile and sequence of the shock waves were evaluated qualitatively. Guided by this analysis, the design of the reflector insert had been refined to suppress the intraluminal bubble expansion, which was confirmed by high-speed imaging of bubble dynamics both in free field and inside a vessel phantom. The pulse pressure, beam size and stone comminution efficiency of the upgraded reflector were all found to be comparable to those of the original reflector. However, the greatest difference lies in the propensity for tissue injury. At the lithotripter focus, about 30 shocks are needed to cause a rupture of the vessel phantom using the original reflector, but no rupture can be produced after 200 shocks by the upgraded reflector. Overall, the upgraded reflector could significantly reduce the propensity of vessel rupture while maintaining satisfactory stone comminution. Second, to improve stone comminution in SWL a new piezoelectric annular array (PEAA) generator made of 1--3 piezocomposite material was fabricated and retrofitted on a clinical HM-3 lithotripter. The operation of the integrated lithotripter system can be controlled by an automatic program. The shock wave produced by the PEAA generator was used to intensify the collapse of LSW-induced bubbles near the target stone. In vitro experiments have shown that combining the upgraded reflector with the PEAA generator could produce better stone comminution efficiency after 1,500 shock (95.25%) than that produced by the original reflector (81.58%). In animal experiments, a BegoStone phantom was implanted into the renal pelvis of right porcine kidney from the urinary tract and exposed up to 2,000 shocks produced by different lithotripter configurations. Better stone comminution efficiencies can be achieved by using the upgraded reflector and the combined system (91.6% and 93.2%, respectively) than the original HM-3 reflector (87.6%). Meanwhile, the volume percentages of gross injury produced by the upgraded reflector and the combined system (0.92% and 0.71%, respectively) are found to be less than that of the original reflector (1.69%). All together, it has been shown both in vitro and in vivo that optimization of lithotripter pressure waveform, distribution, and sequence can improve stone comminution efficiency and reduce simultaneously the propensity of tissue injury.

  18. Enterococcal endocarditis after extracorporeal shock wave lithotripsy for nephrolithiasis.

    PubMed Central

    Zimhony, O.; Goland, S.; Malnick, S. D.; Singer, D.; Geltner, D.

    1996-01-01

    We report a case of enterococcal endocarditis following extracorporeal shock wave lithotripsy (ESWL) for ureteral stone. Although endocarditis following ESWL is very rare, transient bacteraemia occurs during ESWL. This case is a reminder that enterococcal endocarditis may follow innovative genitourinary procedures without appropriate prophylaxis. PMID:8746286

  19. Incidence and risk factors of renal hematoma: a prospective study of 1,300 SWL treatments.

    PubMed

    Schnabel, M J; Gierth, M; Chaussy, C G; Dötzer, K; Burger, M; Fritsche, H M

    2014-06-01

    Shock wave lithotripsy (SWL) is the gold standard for the treatment of upper urinary tract stones. Despite being relatively non-invasive, SWL can cause renal hematoma (RHT). The aim of this study was to determine incidence and risk factors for RHT following SWL. 857 patients were included in a prospectively maintained database. The observation period spans from 2007 to 2012. 1,324 procedures were performed due to kidney stones. Treatment protocol included power ramping and shock wave frequency of 60-90 per minute as well as an ultrasound check within 3 days of SWL for all patients. Patients with RHT were analyzed, and treatment characteristics were compared with the complete population in a non-statistical manner due to the low event count. RHTs after SWL, sized between 2.6 × 0.6 cm and 17 × 15 cm, were verified in seven patients (0.53%). In four patients, the RHT was asymptomatic. Three patients developed pain after SWL treatment due to a RHT. In one patient surgical intervention was necessary due to a symptomatic RHT, the kidney was preserved. The risk of RHT following SWL treatment of kidney stones is about 0.5%. Clinically relevant or symptomatic RHTs occur in 0.23%, RHTs requiring surgical intervention are extremely rare. Older age and vascular comorbidities appear to be risk factors for the development of RHT. The technical characteristics of SWL treatment and intake of low-dose acetylsalicylic acid due to an imperative cardiologic indication do not appear to influence the risk. Prospective studies are warranted. PMID:24419328

  20. Shock wave lithotripsy outcomes for lower pole and non-lower pole stones from a university teaching hospital: Parallel group comparison during the same time period

    PubMed Central

    Geraghty, Robert; Burr, Jacob; Simmonds, Nick; Somani, Bhaskar K.

    2015-01-01

    Introduction: Shock wave lithotripsy (SWL) is a treatment option for all locations of renal and ureteric stones. We compared the results of SWL for lower pole renal stones with all other non-lower pole renal and ureteric stones during the same time period. Material and Methods: All SWL procedures were carried out as day case procedures by a mobile lithotripter from January 2012 to August 2013. The follow-up imaging was a combination of KUB X-ray or USS. Following SWL treatment, the stone free rate (SFR) was defined as ≤3 mm fragments. Results: A total of 148 patients with a mean age of 62 years underwent 201 procedures. Of the 201 procedures, 93 (46%) were for lower pole stones. The non-lower pole stones included upper pole (n = 36), mid pole (n = 40), renal pelvis (n = 10), PUJ (n = 8), mid ureter (n = 3), upper ureter (n = 5) and a combination of upper, middle and/or lower pole (n = 6). The mean stone size for lower pole stones (7.4 mm; range: 4-16 mm) was slightly smaller than non-lower pole stones (8 mm; range: 4-17 mm). The stone fragmentation was successful in 124 (62%) of patients. However, the SFR was statistically significantly better (P = 0.023) for non-lower pole stones 43 (40%) compared to lower pole stones 23 (25%). There were 9 (4%) minor complications and this was not significantly different in the two groups. Conclusions: Although SWL achieves a moderately high stone fragmentation rate with a low complication rate, the SFR is variable depending on the location of stone and the definition of SFR, with lower pole stones fairing significantly worse than stones in all other locations. PMID:25657543

  1. Does ureteral stenting matter for stone size? A retrospectıve analyses of 1361 extracorporeal shock wave lithotripsy patients

    PubMed Central

    Dogan, Cagatay; Can, Gulce Ecem; Tansu, Nejat; Erozencı, Ahmet; Onal, Bulent

    2015-01-01

    Introduction The aim of our study was to determine the efficacy of ureteral stents for extracorporeal shock wave lithotripsy (SWL) treatment of pelvis renalis stones and to compare the results and complications in stented and non-stented patients. Material and methods Between 1995 and 2011, 1361 patients with pelvis renalis stones were treated with SWL. Patients were subdivided into three groups according to stone burden: ≤1 cm2 (group 1; n = 514), 1.1 to 2 cm2 (group 2; n = 530) and >2 cm2 (group 3; n = 317). Each group was divided into subgroups of patients who did and did not undergo ureteral stent implantation before SWL treatment. The efficacy of treatment was evaluated by determining the effectiveness quotient (EQ). Statistical analysis was performed by chi-square, Fisher's exact and Mann-Whitney U tests. Results Of the 514, 530 and 317 patients in groups 1, 2 and 3 respectively, 30 (6%), 44 (8%) and 104 (33%) patients underwent auxiliary stent implantation. Steinstrasse rates did not differ significantly between stented and non-stented patients in each group. The EQ was calculated as 62%, 33% and 70% respectively in non-stented, stented and totally for group 1. This ratio calculated as 58%, 25% and 63% for group 2 and 62%, 26% and 47% for group 3. Stone-free rates were significantly higher for non-stented than for stented patients in groups 2 and 3. Conclusions Stone free rates are significantly higher in non-stented than in stented patients with pelvis renalis stones >1 cm2, whereas steinstrasse rates are not affected. PMID:26568882

  2. One hundred cases of anaesthesia for extracorporeal shock wave lithotripsy.

    PubMed Central

    Frank, M.; McAteer, E. J.; Cohen, D. G.; Blair, I. J.

    1985-01-01

    One hundred cases of anaesthesia for Extracorporeal Shock Wave Lithotripsy (ESWL) are described. Epidural or general anaesthesia was used. Anaesthetic complications were mainly cardiovascular, namely hypotension and bradycardia. With increased experience, it was noted that the use of minimal concentrations of general anaesthetic agents, or epidural anaesthesia supplemented with ephedrine, decreased the incidence of these problems. There was a low incidence of nausea or vomiting or analgesic requirements postoperatively, and the average length of stay in hospital postoperatively was 3 days. PMID:4073761

  3. Eosinophilic pleural effusion: a rare complication of extracorporeal shock wave lithotripsy.

    PubMed

    Mokhtari, Maral; Kumar, Perikala Vijayananda; Ghayumi, Mohammad-Ali

    2013-01-01

    Background. Extracorporeal shock wave lithotripsy has been widely used to treat renal stones. The procedure is relatively safe with minor complications. Case. The patient is a 32-year-old man who presented with left sided pleural effusion after extracorporeal shock wave lithotripsy. Results. The pleural effusion study revealed an exudative fluid rich in eosinophils (30%). So, the diagnosis of eosinophilic pleural effusion as a complication of lithotripsy was made. Conclusion. Extracorporeal shock wave lithotripsy should be regarded as an etiology of unexplained eosinophilic pleural effusion after this procedure. PMID:23935633

  4. The effects of extracorporeal shock wave lithotripsy on pacemaker function.

    PubMed

    Langberg, J; Abber, J; Thuroff, J W; Griffin, J C

    1987-09-01

    Twenty-two pacemaker pulse generators were exposed to shock waves of an extracorporeal shock wave lithotripter to assess the effects of the extremely high pressure transients on pacemaker function. The pulse generator and distal aspect of the lead were positioned 5 cm from the focal point of the lithotripter and 10 cm from each other. Pulse generator function was analyzed during shock wave delivery synchronized with pulse generator output, during shock waves at a rate faster than the escape rate, and after exposure to lithotripsy. During shock waves delivered synchronously with pulse generator output, only one of 22 pulse generators malfunctioned by intermittently reverting to the magnet rate. When subjected to shock waves at a rate greater than the escape rate, 50% of the pulse generators were inhibited by electromechanical interference from the lithotripter. Both bipolar and unipolar devices were affected. However, analysis after exposure to shock waves showed that none of the pacemakers was damaged or spuriously reprogrammed. In conclusion, cardiac pacemakers do not appear to be damaged or reprogrammed by exposure to extracorporeal shock wave lithotripsy. The likelihood of false inhibition appears to be very low if shock waves are delivered synchronously with the QRS. PMID:2444938

  5. Tracking kidney stones with sound during shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Kracht, Jonathan M.

    The prevalence of kidney stones has increased significantly over the past decades. One of the primary treatments for kidney stones is shock wave lithotripsy which focuses acoustic shock waves onto the stone in order to fragment it into pieces that are small enough to pass naturally. This typically requires a few thousand shock waves delivered at a rate of about 2 Hz. Although lithotripsy is the only non-invasive treatment option for kidney stories, both acute and chronic complications have been identified which could be reduced if fewer shock waves were used. One factor that could be used to reduce the number of shock waves is accounting for the motion of the stone which causes a portion of the delivered shock waves to miss the stone, yielding no therapeutic benefit. Therefore identifying when the stone is not in focus would allow tissue to be spared without affecting fragmentation. The goal of this thesis is to investigate acoustic methods to track the stone in real-time during lithotripsy in order to minimize poorly-targeted shock waves. A relatively small number of low frequency ultrasound transducers were used in pulse-echo mode and a novel optimization routine based on time-of-flight triangulation is used to determine stone location. It was shown that the accuracy of the localization may be estimated without knowing the true stone location. This method performed well in preliminary experiments but the inclusion of tissue-like aberrating layers reduced the accuracy of the localization. Therefore a hybrid imaging technique employing DORT (Decomposition of the Time Reversal Operator) and the MUSIC (Multiple Signal Classification) algorithm was developed. This method was able to localize kidney stories to within a few millimeters even in the presence of an aberrating layer. This would be sufficient accuracy for targeting lithotripter shock waves. The conclusion of this work is that tracking kidney stones with low frequency ultrasound should be effective clinically.

  6. Goodpasture's disease following extracorporeal shock wave lithotripsy: a case report & literature review.

    PubMed

    Cranfield, Alistair; Mathavakkannan, Suresh

    2015-03-01

    Shock wave lithotripsy may unmask epitopes within the glomerular basement membrane, leading to the formation of anti-glomerular basement membrane (GBM) antibodies and clinical disease in susceptible individuals. Although rare, our case highlights the need for vigilant monitoring of renal function following extracorporeal shock wave lithotripsy. This may allow for early recognition, treatment and improved outcome of anti-GBM disease. PMID:25838905

  7. Adverse effects of shock waves and strategies for improved treatment in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    McAteer, James A.; Evan, Andrew P.; Connors, Bret A.; Williams, James C.; Willis, Lynn R.

    2005-04-01

    Lithotripter SWs rupture blood vessels in the kidney. This acute trauma, accompanied by a fall in renal function, can lead to significant long-term effects such as profound scarring of the kidney cortex and renal papillaea permanent loss of functional renal mass. SWL has been linked to new-onset hypertension in some patients, and recent studies suggest that multiple lithotripsies can actually alter a patient's stone disease leading to formation of stones (brushite) that are harder to break. Cavitation and shear appear to play a role in stone breakage and tissue damage. Progress in understanding these mechanisms, and the renal response to SWs, has led to practical strategies to improve treatment. Slowing the SW-rate, or initiating treatment at low kV/power both improve stone breakage and reduce the number of potentially tissue-damaging SWs needed to achieve comminution. The observation that SWs cause transient vasoconstriction in the kidney has led to studies in pigs showing that a pre-conditioning dose of low-energy SWs significantly reduces trauma from subsequent high-energy SWs. Thus, SWs can induce adverse effects in the kidney, but what we have learned about the mechanisms of SW action suggests strategies that could make lithotripsy safer and more effective. [Work supported by NIH-DK43881, DK55674.

  8. Turbulent Water Coupling in Shock Wave Lithotripsy

    PubMed Central

    Lautz, Jaclyn; Sankin, Georgy; Zhong, Pei

    2013-01-01

    Previous studies have demonstrated that stone comminution decreases with increased pulse repetition frequency as a result of bubble proliferation in the cavitation field of a shock wave lithotripter (Pishchalnikov et al., 2011). If cavitation nuclei remain in the propagation path of successive lithotripter pulses, especially in the acoustic coupling cushion of the shock wave source, they will consume part of the incident wave energy, leading to reduced tensile pressure in the focal region and thus lower stone comminution efficiency. We introduce a method to remove cavitation nuclei from the coupling cushion between successive shock exposures using a jet of degassed water. As a result, pre-focal bubble nuclei lifetime quantified by B-mode ultrasound imaging was reduced from 7 s to 0.3 s by a jet with an exit velocity of 62 cm/s. Stone fragmentation (percent mass < 2 mm) after 250 shocks delivered at 1 Hz was enhanced from 22 ± 6% to 33 ± 5% (p = 0.007) in water without interposing tissue mimicking materials. Stone fragmentation after 500 shocks delivered at 2 Hz was increased from 18 ± 6% to 28 ± 8% (p = 0.04) with an interposing tissue phantom of 8 cm thick. These results demonstrate the critical influence of cavitation bubbles in the coupling cushion on stone comminution and suggest a potential strategy to improve the efficacy of contemporary shock wave lithotripters. PMID:23322027

  9. Effective radiation exposure evaluation during a one year follow-up of urolithiasis patients after extracorporeal shock wave lithotripsy

    PubMed Central

    Tekinarslan, Erdem; Keskin, Suat; Buldu, İbrahim; Sönmez, Mehmet Giray; Karatag, Tuna; Istanbulluoglu, Mustafa Okan

    2015-01-01

    Introduction To determine and evaluate the effective radiation exposure during a one year follow-up of urolithiasis patients following the SWL (extracorporeal shock wave lithotripsy) treatment. Material and methods Total Effective Radiation Exposure (ERE) doses for each of the 129 patients: 44 kidney stone patients, 41 ureter stone patients, and 44 multiple stone location patients were calculated by adding up the radiation doses of each ionizing radiation session including images (IVU, KUB, CT) throughout a one year follow-up period following the SWL. Results Total mean ERE values for the kidney stone group was calculated as 15, 91 mSv (5.10-27.60), for the ureter group as 13.32 mSv (5.10-24.70), and in the multiple stone location group as 27.02 mSv (9.41-54.85). There was no statistically significant differences between the kidney and ureter groups in terms of the ERE dose values (p = 0.221) (p >0.05). In the comparison of the kidney and ureter stone groups with the multiple stone location group; however, there was a statistically significant difference (p = 0.000) (p <0.05). Conclusions ERE doses should be a factor to be considered right at the initiation of any diagnostic and/or therapeutic procedure. Especially in the case of multiple stone locations, due to the high exposure to ionized radiation, different imaging modalities with low dose and/or totally without a dose should be employed in the diagnosis, treatment, and follow-up bearing the aim to optimize diagnosis while minimizing the radiation dose as much as possible. PMID:26568880

  10. Turbulent water coupling in shock wave lithotripsy.

    PubMed

    Lautz, Jaclyn; Sankin, Georgy; Zhong, Pei

    2013-02-01

    Previous studies have demonstrated that stone comminution decreases with increased pulse repetition frequency as a result of bubble proliferation in the cavitation field of a shock wave lithotripter (Pishchalnikov et al 2011 J. Acoust. Soc. Am. 130 EL87-93). If cavitation nuclei remain in the propagation path of successive lithotripter pulses, especially in the acoustic coupling cushion of the shock wave source, they will consume part of the incident wave energy, leading to reduced tensile pressure in the focal region and thus lower stone comminution efficiency. We introduce a method to remove cavitation nuclei from the coupling cushion between successive shock exposures using a jet of degassed water. As a result, pre-focal bubble nuclei lifetime quantified by B-mode ultrasound imaging was reduced from 7 to 0.3 s by a jet with an exit velocity of 62 cm s(-1). Stone fragmentation (percent mass <2 mm) after 250 shocks delivered at 1 Hz was enhanced from 22 ± 6% to 33 ± 5% (p = 0.007) in water without interposing tissue mimicking materials. Stone fragmentation after 500 shocks delivered at 2 Hz was increased from 18 ± 6% to 28 ± 8% (p = 0.04) with an interposing tissue phantom of 8 cm thick. These results demonstrate the critical influence of cavitation bubbles in the coupling cushion on stone comminution and suggest a potential strategy to improve the efficacy of contemporary shock wave lithotripters. PMID:23322027

  11. Controlled Cavitation to Augment SWL Stone Comminution: Mechanistic Insights In-Vitro

    PubMed Central

    Duryea, Alexander P.; Roberts, William W.; Cain, Charles A.; Hall, Timothy L.

    2013-01-01

    Stone comminution in shock wave lithotripsy (SWL) has been documented to result from mechanical stresses conferred directly to the stone, as well as the activity of cavitational microbubbles. Studies have demonstrated that the presence of this cavitation activity is crucial for stone subdivision; however, its exact role in the comminution process remains somewhat weakly defined, in part due to the fact that it is difficult to isolate the cavitational component from the shock waves themselves. In this study, we further explored the importance of cavitation in SWL stone comminution through the use of histotripsy ultrasound therapy. Histotripsy was utilized to target model stones designed to mimic the mid-range tensile fracture strength of naturally occurring cystine calculi with controlled cavitation at strategic time points in the SWL comminution process. All SWL was applied at a peak-positive pressure (p+) of 34 MPa and a peak-negative pressure (p−) of 8 MPa; a shock rate of 1 Hz was used. Histotripsy pulses had a p− of 33 MPa and were applied at a pulse repetition frequency (PRF) of 100 Hz. Ten model stones were sonicated in-vitro with each of five different treatment schemes: A. 10 minutes SWL (600 shocks) with 0.7 seconds of histotripsy interleaved between successive shocks (totaling to 42,000 pulses); B. 10 minutes SWL (600 shocks) followed by 10 minutes histotripsy applied in 0.7 second bursts (1 burst per second, totaling to 42,000 pulses); C. 10 minutes histotripsy applied in 0.7 second bursts (42,000 pulses) followed by 10 minutes SWL (600 shocks); D. 10 minutes SWL-only (600 shocks); E. 10 minutes histotripsy-only applied in 0.7 second bursts (42,000 pulses). Following sonication, debris was collected and sieved through 8, 6, 4, and 2 mm filters. It was found that SWL-only generated a broad range of fragment sizes, with an average of 14.9 ± 24.1% of the original stone mass remaining >8 mm. Histotripsy-only eroded the surface of stones to tiny particulate debris that was small enough to pass through the finest filter used in this study (<2 mm), leaving behind a single primary stone piece (>8 mm) with mass 85.1 ± 1.6% of the original following truncated sonication. The combination of SWL and histotripsy (schemes A, B, and C) resulted in a shift in the size distribution toward smaller fragments and complete elimination of debris >8 mm. When histotripsy controlled cavitation was applied following SWL (B), the increase in exposed stone surface area afforded by shock wave stone subdivision led to enhanced cavitation erosion. When histotripsy controlled cavitation was applied prior to SWL (C), it is likely that stone surface defects induced by cavitation erosion provided sights for crack nucleation and accelerated shock wave stone subdivision. Both these effects are likely at play in the interleaved therapy (A), although shielding of shock waves by remnant histotripsy microbubble nuclei may have limited the efficacy of this scheme. Nevertheless, these results demonstrate the important role played by cavitation in the stone comminution process, and suggest that the application of controlled cavitation at strategic time points can provide an adjunct to traditional SWL therapy. PMID:23357904

  12. Goodpasture's disease following extracorporeal shock wave lithotripsy: a case report & literature review

    PubMed Central

    Cranfield, Alistair; Mathavakkannan, Suresh

    2015-01-01

    Key Clinical Message Shock wave lithotripsy may unmask epitopes within the glomerular basement membrane, leading to the formation of anti-glomerular basement membrane (GBM) antibodies and clinical disease in susceptible individuals. Although rare, our case highlights the need for vigilant monitoring of renal function following extracorporeal shock wave lithotripsy. This may allow for early recognition, treatment and improved outcome of anti-GBM disease. PMID:25838905

  13. Radiation exposure to patients during extracorporeal shock wave lithotripsy

    SciTech Connect

    Van Swearingen, F.L.; McCullough, D.L.; Dyer, R.; Appel, B.

    1987-07-01

    Extracorporeal shock wave lithotripsy is rapidly becoming an accepted treatment of renal calculi. Since fluoroscopy is involved to image the stones it is important to know how much radiation the patient receives during this procedure. Surface radiation exposure to the patient was measured in more than 300 fluoroscopic and radiographic procedures using thermoluminescent dosimeters. Initial results showed an average skin exposure of 10.1 rad per procedure for each x-ray unit, comparing favorably with exposure rates for percutaneous nephrostolithotomy and other routine radiological procedures. Factors influencing exposure levels include stone characteristics (location, size and opacity), physician experience and number of shocks required. Suggestions are given that may result in a 50 per cent reduction of radiation exposure.

  14. Stone heterogeneity index as the standard deviation of Hounsfield units: A novel predictor for shock-wave lithotripsy outcomes in ureter calculi.

    PubMed

    Lee, Joo Yong; Kim, Jae Heon; Kang, Dong Hyuk; Chung, Doo Yong; Lee, Dae Hun; Do Jung, Hae; Kwon, Jong Kyou; Cho, Kang Su

    2016-01-01

    We investigated whether stone heterogeneity index (SHI), which a proxy of such variations, was defined as the standard deviation of a Hounsfield unit (HU) on non-contrast computed tomography (NCCT), can be a novel predictor for shock-wave lithotripsy (SWL) outcomes in patients with ureteral stones. Medical records were obtained from the consecutive database of 1,519 patients who underwent the first session of SWL for urinary stones between 2005 and 2013. Ultimately, 604 patients with radiopaque ureteral stones were eligible for this study. Stone related variables including stone size, mean stone density (MSD), skin-to-stone distance, and SHI were obtained on NCCT. Patients were classified into the low and high SHI groups using mean SHI and compared. One-session success rate in the high SHI group was better than in the low SHI group (74.3% vs. 63.9%, P = 0.008). Multivariate logistic regression analyses revealed that smaller stone size (OR 0.889, 95% CI: 0.841-0.937, P < 0.001), lower MSD (OR 0.995, 95% CI: 0.994-0.996, P < 0.001), and higher SHI (OR 1.011, 95% CI: 1.008-1.014, P < 0.001) were independent predictors of one-session success. The radiologic heterogeneity of urinary stones or SHI was an independent predictor for SWL success in patients with ureteral calculi and a useful clinical parameter for stone fragility. PMID:27035621

  15. Stone heterogeneity index as the standard deviation of Hounsfield units: A novel predictor for shock-wave lithotripsy outcomes in ureter calculi

    PubMed Central

    Lee, Joo Yong; Kim, Jae Heon; Kang, Dong Hyuk; Chung, Doo Yong; Lee, Dae Hun; Do Jung, Hae; Kwon, Jong Kyou; Cho, Kang Su

    2016-01-01

    We investigated whether stone heterogeneity index (SHI), which a proxy of such variations, was defined as the standard deviation of a Hounsfield unit (HU) on non-contrast computed tomography (NCCT), can be a novel predictor for shock-wave lithotripsy (SWL) outcomes in patients with ureteral stones. Medical records were obtained from the consecutive database of 1,519 patients who underwent the first session of SWL for urinary stones between 2005 and 2013. Ultimately, 604 patients with radiopaque ureteral stones were eligible for this study. Stone related variables including stone size, mean stone density (MSD), skin-to-stone distance, and SHI were obtained on NCCT. Patients were classified into the low and high SHI groups using mean SHI and compared. One-session success rate in the high SHI group was better than in the low SHI group (74.3% vs. 63.9%, P = 0.008). Multivariate logistic regression analyses revealed that smaller stone size (OR 0.889, 95% CI: 0.841–0.937, P < 0.001), lower MSD (OR 0.995, 95% CI: 0.994–0.996, P < 0.001), and higher SHI (OR 1.011, 95% CI: 1.008–1.014, P < 0.001) were independent predictors of one-session success. The radiologic heterogeneity of urinary stones or SHI was an independent predictor for SWL success in patients with ureteral calculi and a useful clinical parameter for stone fragility. PMID:27035621

  16. Histopathologic effects of extracorporeal shock wave lithotripsy on rabbit kidney.

    PubMed

    Karalezli, G; Gögüş, O; Bedük, Y; Köküuslu, C; Sarica, K; Kutsal, O

    1993-01-01

    Despite the widespread clinical use of the lithotriptor, the margin of safety for the kidney during shock wave application is substantially unknown. Although a series of pilot studies have been performed in laboratory animals, long-term follow-up is mandatory to establish the effect of extracorporeal shock wave lithotripsy (ESWL) and subsequent dose-dependent changes on the kidneys. An experimental study was performed in 45 rabbits; to define and compare the early and late complications of ESWL in the kidneys. The rabbits were divided into three groups of 15 animals each that received 1000, 1500 or 3000 shock waves respectively at 15-20 kV. The rabbits in each group were killed and necropsy performed within 24 h for the first 5 animals, 1 week for the second 5 animals and 2 months post-ESWL for the last 5 animals. Dose-dependent moderate damage (subcapsular hemorrhage, interstitial hemorrhage, capsular tension and perirenal hemorrhage) were noted in all kidneys at 24 h after treatment. Evidence of permanent changes (some fibrosis, tubular and glomerular damage, chronic inflammatory alterations) was noted in long-term follow up. Complete necrosis of the treated kidney was not encountered in this study. PMID:8456541

  17. Transient cavitation produced by extracorporeal shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Cioanta, Iulian

    1998-12-01

    Two decades ago, a new medical procedure was introduced, allowing the fragmentation of kidney stones from outside the human body (noninvasively) using a shock wave device termed lithotripter ('stone crusher'). Considered as one of the most important medical inventions of this century, lithotripsy is currently used in more than 80% of urolithiasis cases. Experimental studies have shown that transient or inertial cavitation is generated by this procedure near the stones and in renal tissue. To find a correlation between the number of shocks delivered and the treatment efficiency, the acoustic emission (AE) generated by the oscillation of cavitation bubbles, and its relation with stone fragmentation and tissue damage during shock wave lithotripsy were studied. In vitro experiments were carried out to identify the correlation between the AE signals and the expansion and collapse of cavitation bubbles, which were captured by high-speed photography (20,000 frames per second). This correlation has been verified on four different electrohydraulic lithotripters, under multiple experimental conditions. The effects of tissue attenuation on AE and stone fragmentation were also studied. The in vitro results have further allowed the interpretation of AE signals from in vivo experiments with pigs. Although similar in general trend, in vivo AE signals are found to be shorter in expansion and longer in the total ringing times (including the rebound phenomenon) than for in vitro AE signals, indicating a tissue constraining effect on bubble oscillation. Based on this observation a new mechanism for renal vascular and tubular injury is proposed. In addition, changes in AE signals have been observed as the total number of shocks increases, and this dose dependence feature has allowed the determination of a threshold value for extended tissue injury at 20 kV. This result has been confirmed by histological analysis and by results of a theoretical model study of bubble oscillation in a tissue mimicking membrane structure. To improve the efficiency of stone fragmentation and to reduce tissue injury, a new design for lithotripters shock wave reflector has been proposed and tested in vitro.

  18. Shock wave lithotripsy at 60 or 120 shocks per minute: A randomized, double-blinded trial

    NASA Astrophysics Data System (ADS)

    Pace, Kenneth; Ghiculete, Daniela; Harju, Melanie; Honey, R. John

    2005-04-01

    Rate of shock wave administration is a factor in the per-shock efficiency of SWL. Decreasing shock wave frequency from 120 shocks per minute (s/m) may improve stone fragmentation. This study is the first to test this hypothesis in vivo. Patients with previously untreated radio-opaque kidney stones were randomized to SWL at 60 or 120 s/m and followed at 2 weeks and 3 months. Primary outcome was success rate, defined as stone-free or asymptomatic fragments 5 mm in size 3 months post-treatment. 111 patients were randomized to 60 s/m and 109 to 120 s/m. The groups were comparable on age, gender, BMI, stent status, and initial stone area. Success rate was higher for 60 s/m (75% versus 61%, p=0.027). Patients with stone area 100 mm2 experienced the greatest benefit: success rates were 71% for 60 s/m versus 32% (p=0.002), and stone-free rates were 60% versus 28% (p=0.015). Repeat SWL treatment was required in 32% treated at 120 s/m versus 18% (p=0.018). Fewer shocks were required (2423 versus 2906, p=0.001), but treatment time was longer (40.6 versus 24.2 minutes, p=0.001). SWL treatment at 60 s/m yields better outcomes than 120 s/m, particularly for stones 100 mm2.

  19. [Medical and Economic Aspects of Extracorporeal Shock Wave Lithotripsy].

    PubMed

    Knoll, T; Fritsche, H-M; Rassweiler, J

    2011-11-01

    Extracorporeal shock wave lithotripsy (ESWL) is the method of choice for most renal and ureteral calculi. However, endoscopic procedures such as ureteroscopy or percutaneous nephrolithotomy are being more and more performed as primary treatment alternatives in clinical routine. This development may result from the sometimes unsatisfying results of ESWL. While this is often explained by a lower efficacy of last-generation machines, an often unrecognized explanation is the impact of a less well trained urologist. To achieve best results it is mandatory that fundamental knowledge about shock wave physics and disintegration mechanisms are available. In Germany, the reimbursement system between outpatient and inpatient departments is totally separate. This leads to difficulties in clinical practice. We believe that patients at risk for complications, such as ureteral stones, urinary tract infections or high age, benefit from inpatient treatment, while uncomplicated renal stones can safely be treated on an outpatient basis. Regular application and training of ESWL will aid an optimization of its results and acceptance. PMID:22090371

  20. Ureteral stenting with extracorporeal shock-wave lithotripsy.

    PubMed

    Cass, A S

    1992-05-01

    We reviewed the results of ureteral stent use with extracorporeal shock-wave lithotripsy (ESWL) in 3,096 patients with renal calculi less than 3 cm in diameter. The 2,595 patients with indwelling ureteral stents required lower total power (shocks x voltage) and less radiation and had a lower secondary procedure rate but a higher retreatment rate than the 501 patients without stents. However, the only statistically significant difference was in the average radiation dose in patients with or without stents and single stones no larger than 10 mm (16 vs. 18 rad). The hospital stay was one day or less in 98 percent of the patients in both groups. With an 80 percent follow-up rate at three months indwelling ureteral stents were associated with a higher stone-free rate in patients with a single stone but a lower stone-free rate in patients with multiple stones, compared with those treated without a stent. An indwelling ureteral stent may result in urinary frequency and bladder discomfort in some patients, and with no statistical difference in the results with or without a ureteral stent it is questionable whether or not the high use of an indwelling ureteral stent is justified in patients admitted for one day or less. PMID:1580036

  1. Pediatric extracorporeal shock wave lithotripsy: Predicting successful outcomes

    PubMed Central

    McAdams, Sean; Shukla, Aseem R.

    2010-01-01

    Extracorporeal shock wave lithotripsy (ESWL) is currently a first-line procedure of most upper urinary tract stones <2 cm of size because of established success rates, its minimal invasiveness and long-term safety with minimal complications. Given that alternative surgical and endourological options exist for the management of stone disease and that ESWL failure often results in the need for repeat ESWL or secondary procedures, it is highly desirable to identify variables predicting successful outcomes of ESWL in the pediatric population. Despite numerous reports and growing experience, few prospective studies and guidelines for pediatric ESWL have been completed. Variation in the methods by which study parameters are measured and reported can make it difficult to compare individual studies or make definitive recommendations. There is ongoing work and a need for continuing improvement of imaging protocols in children with renal colic, with a current focus on minimizing exposure to ionizing radiation, perhaps utilizing advancements in ultrasound and magnetic resonance imaging. This report provides a review of the current literature evaluating the patient attributes and stone factors that may be predictive of successful ESWL outcomes along with reviewing the role of pre-operative imaging and considerations for patient safety. PMID:21369388

  2. Ureteral wall thickness at the impacted ureteral stone site: a critical predictor for success rates after SWL.

    PubMed

    Sarica, Kemal; Kafkasli, Alper; Yazici, Özgür; Çetinel, Ali Cihangir; Demirkol, Mehmet Kutlu; Tuncer, Murat; Şahin, Cahit; Eryildirim, Bilal

    2015-02-01

    The aim of the study was to determine the possible predictive value of certain patient- and stone-related factors on the stone-free rates and auxiliary procedures after extracorporeal shock wave lithotripsy in patients with impacted proximal ureteral calculi. A total of 111 patients (86 male, 25 females M/F: 3.44/1) with impacted proximal ureteral stones treated with shock wave lithotripsy were evaluated. Cases were retrieved from a departmental shock wave lithotripsy database. Variables analyzed included BMI of the case, diameter of proximal ureter and renal pelvis, stone size and Hounsfield unit, ureteral wall thickness at the impacted stone site. Stone-free status on follow-up imaging at 3 months was considered a successful outcome. All patients had a single impacted proximal ureteral stone. While the mean age of the cases was 46 ± 13 years (range 26-79 years), mean stone size was 8.95 mm (5.3-15.1 mm). Following shock wave lithotripsy although 87 patients (78.4%) were completely stone-free at 3-month follow-up visit, 24 (21.6%) cases had residual fragments requiring further repeat procedures. Prediction of the final outcome of SWL in patients with impacted proximal ureteral stones is a challenging issue and our data did clearly indicate a highly significant relationship between ureteral wall thickness and the success rates of shock wave lithotripsy particularly in cases requiring additional procedures. Of all the evaluated stone- and patient-related factors, only ureteral wall thickness at the impacted stone site independently predicted shock wave lithotripsy success. PMID:25417717

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

    PubMed Central

    Jakobs, R; Adamek, H E; Maier, M; Krömer, M; Benz, C; Martin, W R; Riemann, J F

    1997-01-01

    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. PMID:9203950

  4. Intrahepatic hematoma requiring hepatic artery embolization: a rare complication of extracorporeal shock wave lithotripsy.

    PubMed

    Pei, Y Veronica

    2013-09-01

    Extracorporeal shock wave lithotripsy is a well-established treatment modality for renal calculi since the 1980s (Urology 1984;23(5):59–66). In general, it is a safe and effective noninvasive therapeutic modality for treatment of urolithiasis. Bleeding complications of this procedure are rare and usually involve the kidneys. In this case report, a 56-year-old woman developed severe abdominal pain with signs of hemorrhagic shock 2 days post–extracorporeal shock wave lithotripsy procedure. Computed tomography of the abdomen and pelvis showed a large intrahepatic hemorrhage that required hepatic artery embolization. PMID:23791461

  5. Modeling elastic wave propagation in kidney stones with application to shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Cleveland, Robin O.; Sapozhnikov, Oleg A.

    2005-10-01

    A time-domain finite-difference solution to the equations of linear elasticity was used to model the propagation of lithotripsy waves in kidney stones. The model was used to determine the loading on the stone (principal stresses and strains and maximum shear stresses and strains) due to the impact of lithotripsy shock waves. The simulations show that the peak loading induced in kidney stones is generated by constructive interference from shear waves launched from the outer edge of the stone with other waves in the stone. Notably the shear wave induced loads were significantly larger than the loads generated by the classic Hopkinson or spall effect. For simulations where the diameter of the focal spot of the lithotripter was smaller than that of the stone the loading decreased by more than 50%. The constructive interference was also sensitive to shock rise time and it was found that the peak tensile stress reduced by 30% as rise time increased from 25 to 150 ns. These results demonstrate that shear waves likely play a critical role in stone comminution and that lithotripters with large focal widths and short rise times should be effective at generating high stresses inside kidney stones.

  6. Modeling elastic wave propagation in kidney stones with application to shock wave lithotripsy.

    PubMed

    Cleveland, Robin O; Sapozhnikov, Oleg A

    2005-10-01

    A time-domain finite-difference solution to the equations of linear elasticity was used to model the propagation of lithotripsy waves in kidney stones. The model was used to determine the loading on the stone (principal stresses and strains and maximum shear stresses and strains) due to the impact of lithotripsy shock waves. The simulations show that the peak loading induced in kidney stones is generated by constructive interference from shear waves launched from the outer edge of the stone with other waves in the stone. Notably the shear wave induced loads were significantly larger than the loads generated by the classic Hopkinson or spall effect. For simulations where the diameter of the focal spot of the lithotripter was smaller than that of the stone the loading decreased by more than 50%. The constructive interference was also sensitive to shock rise time and it was found that the peak tensile stress reduced by 30% as rise time increased from 25 to 150 ns. These results demonstrate that shear waves likely play a critical role in stone comminution and that lithotripters with large focal widths and short rise times should be effective at generating high stresses inside kidney stones. PMID:16266186

  7. [Shock wave lithotripsy, retrograde intrarenal surgery or percutaneous nephrolithotomy for lower pole renal stones?].

    PubMed

    Rojas, Alejandro; Gallegos, Héctor; Salvadó, José A

    2015-01-01

    Among the therapeutic alternatives available for the treatment of lower pole renal calculi are extracorporeal lithotripsy, percutaneous nephrolithotomy and retrograde intrarenal surgery. There is controversy about which of these techniques is more effective, especially for stones smaller than 20 mm. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified four systematic reviews including 11 pertinent randomized controlled trials overall. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded percutaneous nephrolithotomy probably increases success rate, but it is not clear if it decreases the need of retreatment compared to extracorporeal shock wave lithotripsy. In comparison to retrograde intrarenal surgery, it may increase success rate, but it is not clear if it decreases the need of retreatment. Retrograde intrarenal surgery may increase success rate, and probably decreases need of retreatment compared to extracorporeal shock wave lithotripsy. PMID:26352272

  8. Ballistic shock wave lithotripsy in an 18-year-old thoroughbred gelding.

    PubMed Central

    Koenig, J; Hurtig, M; Pearce, S; Henderson, J; Morris, T

    1999-01-01

    Prolonged postoperative recuperation time and restricted exercise were circumvented by using ballistic shock wave lithotripsy to break up an 8-cm diameter vesical calculus and by flushing out the sand-like residue under epidural anesthesia with the horse standing. Recovery was uneventful. Images Figure 1. PMID:10086219

  9. [Experience in phytotherapy in nephrolithiasis patients after extracorporeal shock-wave lithotripsy].

    PubMed

    Tkachuk, V N; Al'-Shukri, S Kh; Rizan, Ammo

    2011-01-01

    Our study of efficacy of Prolit-septo phytotherapy following extracorporeal shock-wave lithotripsy (ESWLT) in patients with nephrolithiasis has demonstrated that Prolit-septo noticeably reduces the time of evacuation from the urinary tract of the destructed stone fragments as well as renal colic incidence and renal inflammation exacerbation. PMID:22279778

  10. Endoscopically controlled electrohydraulic intracorporal shock wave lithotripsy as a new therapy for sialolithiasis: first clinical experiences in comparison to the results of laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Koenigsberger, Rainer; Feyh, Jens; Goetz, Alwin E.; Kastenbauer, E.

    1992-06-01

    The endoscopically controlled electrohydraulic shock wave lithotripsy (EISL) of salivary stones was performed on 29 patients with submandibular duct stones as a new non-surgical treatment of sialolithiasis. Under local anesthesia, a flexible fiberscope with an additional probe to generate shock waves is placed into the submandibular duct. Under endoscopic monitoring the fiberscope is advanced until the stone is identified. For stone disintegration, the probe must be situated 1 mm in front of the concrement. The fragmentation itself is performed by pressure waves generated by a sparkover at the tip of the probe. By means of the endoscopically controlled shock wave lithotripsy (EISL), it was possible to achieve complete stone fragmentation in 20 of 29 patients without serious side effects. In 3 patients only partial stone fragmentation could be achieved due to the stone quality. The endoscopically controlled electrohydraulic intracorporal shock wave lithotripsy (EISL) represents a novel non-invasive therapy for endoscopically accessible salivary gland stones. This therapy is performed on an outpatient basis with little inconvenience to the patient. The advantage in comparison to the endoscopically controlled laser lithotripsy will be discussed.

  11. Numerical simulation of shock wave generation and focusing in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Krimmel, Jeff; Colonius, Tim

    2007-11-01

    Shock wave lithotripsy is a procedure where focused shock waves are fired at kidney stones in order to pulverize them. Many lithotripters with different source mechanisms and reflector shapes (or lenses) are in clinical use, but accurate prediction of focal region pressure is made difficult by nonlinearity and cavitation. We report on development of a numerical simulation framework aimed at accurate prediction of focal region flow physics. Shock wave generation and beam focusing are simulated via the Euler equations with MUSCL-type shock capturing scheme and adaptive mesh-refinement (Berger and Oliger, 1984). In future work, a bubbly cavitating flow model will be added. Electrohydraulic, electromagnetic, and piezoelectric lithotripters are modeled with axisymmetric and three-dimensional geometries. In the electrohydraulic case, a simple expanding bubble model simulates spark firing. In the piezoelectric case, a boundary condition prescribing the motion of individual elements is used. Amplitudes and durations of calculated focal region waveforms are in reasonable agreement with experimental data.

  12. Severe acute pancreatitis with abscess after extracorporeal shock wave lithotripsy: a rare complication.

    PubMed

    Weng, Chu-Hao; Ho, Pei-Yin; Tsai, Chia-Chi; Hsu, Jong-Ming; Chen, Marcelo; Lin, Wun-Rong

    2013-04-01

    Extracorporeal shock wave lithotripsy (ESWL) is a widely accepted procedure for urolithiasis. However, the shock waves do not pass through the body without damage. Here, we reported a 57-year-old man who underwent ESWL four times before, and immediately developed acute pancreatitis and peritoneal abscess after ESWL for a right renal stone. Although the possibility of post-ESWL acute pancreatitis is extremely low, urologists must be aware of this vital complication. PMID:23503874

  13. Renovascular acute renal failure precipitated by extracorporeal shock wave lithotripsy for pancreatic stones.

    PubMed

    Cecere, Nicolas; Goffette, Pierre; Deprez, Pierre; Jadoul, Michel; Morelle, Johann

    2015-08-01

    Extracorporeal shock wave lithotripsy (ESWL) for pancreatic stones is considered a safe and efficient method to facilitate fragmentation and stone removal. We describe the case of a 73-year-old woman with a solitary functioning kidney who presented an acute-onset anuria and renovascular renal failure the day after ESWL. We speculate that vascular calcifications in the area targeted by shock waves played a critical role in renal artery obstruction in the present case. PMID:26251710

  14. The effect of renal cortical thickness on the treatment outcomes of kidney stones treated with shockwave lithotripsy

    PubMed Central

    Luke, Sylvia; Chiu, Peter K.F.; Teoh, Jeremy Y.C.; Wong, Ka-Tak; Hou, Simon S.M.

    2015-01-01

    Purpose Because the shock wave passes through various body tissues before reaching the stone, stone composition may affect the treatment efficacy of shock wave lithotripsy (SWL). We investigated the effect of various tissue components along the shock wave path on the success of SWL. Materials and Methods From October 2008 to August 2010, a total of 206 patients with kidney stones sized 5 to 20 mm were prospectively recruited for a study of the factors that affect the outcome of treatment with a Sonolith Vision lithotripter. Successful SWL was defined as either stone-free status or residual fragments <4 mm at 12 weeks. Logistic regression analysis was performed to assess the factors that predicted treatment outcomes. Potential predictors included the patient's age, shock wave delivery rate, stone volume (SV), mean stone density (MSD), skin-to-stone distance (SSD), and the mean thickness of the three main components along the shock wave path: renal cortical thickness (KT), muscle thickness (MT), and soft-tissue thickness (ST). Results The mean age of the patients was 53.8 years (range, 25-82 years). The overall treatment success rate after one session of SWL was 43.2%. The mean KT, MT, and ST were 26.9, 16.6, and 40.8 mm, respectively. The logistic regression results showed that a slower shock wave delivery rate, smaller SV, a lower MSD, and a thicker KT were found to be significant predictors for successful SWL. SSD, MT, and ST were not predictors of successful treatment. Conclusions Among the main tissue components along the shock wave path, a thicker KT was a favorable factor for successful SWL after adjustment for SV, MSD, and the shock wave delivery rate. PMID:25964839

  15. Extracorporeal shock wave lithotripsy in the treatment of renal and ureteral stones.

    PubMed

    Torricelli, Fábio César Miranda; Danilovic, Alexandre; Vicentini, Fábio Carvalho; Marchini, Giovanni Scala; Srougi, Miguel; Mazzucchi, Eduardo

    2015-01-01

    The use of certain technical principles and the selection of favorable cases can optimize the results of extracorporeal shock wave lithotripsy (ESWL). The aim of this study is to review how ESWL works, its indications and contraindications, predictive factors for success, and its complications. A search was conducted on the Pubmed® database between January 1984 and October 2013 using "shock wave lithotripsy" and "stone" as key-words. Only articles with a high level of evidence, in English, and conducted in humans, such as clinical trials or review/meta-analysis, were included. To optimize the search for the ESWL results, several technical factors including type of lithotripsy device, energy and frequency of pulses, coupling of the patient to the lithotriptor, location of the calculus, and type of anesthesia should be taken into consideration. Other factors related to the patient, stone size and density, skin to stone distance, anatomy of the excretory path, and kidney anomalies are also important. Antibiotic prophylaxis is not necessary, and routine double J stent placement before the procedure is not routinely recommended. Alpha-blockers, particularly tamsulosin, are useful for stones >10mm. Minor complications may occur following ESWL, which generally respond well to clinical interventions. The relationship between ESWL and hypertension/diabetes is not well established. PMID:25909212

  16. The effects of local administration of aminophylline on transureteral lithotripsy.

    PubMed

    Barzegarnezhad, Ayyoub; Firouzian, Abolfazl; Emadi, Seyed Abdollah; Mousanejad, Nadali; Bakhshali, Roksana

    2012-01-01

    Introduction. Urinary stone is a common cause of urinary tract disease. Stone excretion using ureteroscope is effective in inferior ureter. The aim of this study was to investigate the effects of aminophylline on ureteral spasm during ureteroscopy in acute phase of renal colic. Methods. In this double-blind randomized clinical trial, 120 patients with ureteral stones were enrolled and randomized into two groups. The bladder was drained and then received a 150 mL irrigation solution. Irrigation solution was saline and saline plus 10 mL aminophylline at 250 mg dose for control and case groups, respectively. Ureteroscopy and transureteral lithotripsy (TUL) were performed five minutes after irrigation. Results. The mean duration of TUL was 4.2 ± 2.61 min and 8.4 ± 2.9 min for control and case groups, respectively. The successful rate was 95% and 76.1% in case and control groups, respectively. Further extracorporeal shock wave lithotripsy (SWL) was performed in 5% and 30% for patients in case and control groups, respectively. Conclusion. Aminophylline facilitated ureteroscopy and increased the success rate in the treatment of renal colic using TUL. No significant complications from post-TUL were observed. Using aminophylline carries several advantages such as reducing procedure duration, decreasing the need for ureteral and double-J catheter, and reducing stone migration to the kidney and use of SWL. PMID:23082076

  17. Extracorporeal shock wave lithotripsy: our experimental and clinical experience with the Direx machine.

    PubMed

    Servadio, C; Livne, P M; Simon, D

    1990-07-01

    The Direx Tripter X-1 is a modular extracorporeal shock wave system that uses underwater spark gaps as its source for lithotripsy. Experience with 712 treatments in 541 patients has given a fragmentation rate of 99%. Of these patients, 27% had stones larger than 2 cm or multiple stones. A stone free situation at 3 months follow-up was achieved in 75% of the cases. Seventeen percent had small fragments less than 4 mm and 8% had fragments greater than 4 mm. Auxiliary procedures following ESWL were required in 7%. No major complications were seen. The advantages of this system are: modularity, mobility, flexibility, and low cost. PMID:10148920

  18. Acute pancreatitis due to extracorporeal shock wave lithotripsy: a rare complication.

    PubMed

    Limon, Onder; Kantar, Funda Ugur; Sahin, Erkan; Arslan, Murat; Ugurhan, Aslı Aydınoglu

    2014-11-01

    Extracorporeal shock wave lithotripsy (ESWL) is considered the treatment of choice for most renal and upper ureteral stones. Although extensive data have documented its safety, serious complications have been reported in 1% of patients, including acute pancreatitis, perirenal hematoma, urosepsis, venous thrombosis, biliary obstruction, bowel perforation, lung injury, and rupture of aortic aneurysms. Here, we report a 41-year-old woman who underwent ESWL for a calculus at the right renal pelvis and immediately developed acute pancreatitis after the procedure. Although the possibility of post-ESWL acute pancreatitisis extremely low, physicians must be aware of this complication in emergency departments. PMID:24908440

  19. Effect of alkalinization on calcium oxalate monohydrate calculi during extracorporeal shock wave lithotripsy: in vivo experiments.

    PubMed

    Vandeursen, H; De Ridder, D; Demeulenaere, R; Pittomvils, G; Boving, R; Baert, L

    1992-01-01

    Previous in vitro experiments demonstrated the reduced microhardness of calcium oxalate monohydrate (COM) calculi, relative to dry values, when saturated with an alkaline solution (pH = 9.5). Nineteen patients with a COM calculus in the distal ureter which had been resistant to prior extracorporeal shock wave lithotripsy in situ, were treated when the stone was surrounded by alkaline urine. The urine of 14 patients was alkalinized orally by administration of acetazolamine and citrate solution; in 5 other patients direct percutaneous irrigation of sodium bicarbonate via a nephrostomy tube was carried out. The urinary pH just before lithotripsy was greater than or equal to 9 in 17/19 patients. 4,000 shock waves, averaging 18.1 kV generated by the Siemens Lithostar, were delivered onto the calculus. No significant increase of comminution rate was apparent at radiographic control immediately after the treatment and only in half of the cases was evacuation obtained within 3 months. PMID:1316663

  20. Laser-induced shock-wave lithotripsy of canine urocystoliths and nephroliths

    NASA Astrophysics Data System (ADS)

    Woods, J. P.; Bartels, Kenneth E.; Stair, Ernest L.; Schafer, Steven A.; Nordquist, Robert E.

    1997-05-01

    Urolithiasis is a common disease affecting dogs which can sometimes be treated with dietary and medical protocols. In many cases, however, medical management cannot be employed because the dietary restrictions are contraindicated, effective medical dissolution protocols for the calculi (uroliths) do not exist, or obstruction by the calculi may result in deterioration of renal function during the time required for medical dissolution. At present, the management of medically untreatable calculi has been surgical removal which may result in temporary but dramatic decrease in renal function, irreversible loss of damaged nephrons, and significant risk, particularly for bilateral or recurrent nephroliths. An innovative technique for the removal of these uroliths would involve laser lithotripsy which transforms light energy into acoustical energy generating a shock wave sufficient to fragment stones (photoacoustic ablation). The laser is transmitted via quartz fibers which are small and flexible and can be used under direct vision through endoscopes resulting in effective fragmentation with little surrounding tissue damage. Lasers are becoming increasingly more utilized in veterinary medicine, in contrast to the limited availability of other non-invasive methods of treatment of nephroliths (i.e. extracorporeal shock-wave lithotripsy).

  1. Scrotal hematoma resulting from extracorporeal shock wave lithotripsy for a renal calculus: a sign of retroperitoneal hemorrhage

    PubMed Central

    Katz, Darren J.; Dodds, Lachlan J.

    2011-01-01

    We report a rare case of a patient presenting with scrotal hematoma associated with retroperitoneal hemorrhage after extracorporeal shock wave lithotripsy (ESWL). We propose a mechanism for the formation of scrotal hematoma and its importance as a sign of retroperitoneal hemorrhage. PMID:24578909

  2. [Anesthetic management of extracorporeal shock wave lithotripsy: case reports of four young patients with epilepsy].

    PubMed

    Edanaga, Mitsutaka; Azumaguchi, Ryu; Ohsuda, Michiko; Mimura, Mitsuko; Yamakage, Michiaki

    2012-06-01

    Four young patients, including a 7-year-old girl with Aicardi syndrome, an 11-year-old boy with Lennox-Gastaut syndrome, a 22-year-old man with epilepsy due to childhood encephalitis, and a 17-year-old girl with Rett syndrome, were scheduled to undergo extracorporeal shock wave lithotripsy (ESWL) for urolithiasis. Epilepsy in all of the patients was well controlled by medication. Series of ESWL treatment were safely performed under general anesthesia with tracheal intubation. We recommend that maintenance of anesthesia be performed by sevoflurane and nitrous oxide, which can increase threshold of epileptic stroke, and controlled ventilation with a muscle relaxant should be performed to prevent lung or renal injury by the shock wave of ESWL. PMID:22746027

  3. Disseminated tuberculosis after extracorporeal shock-wave lithotripsy in an AIDS patient presenting with urosepsis.

    PubMed

    Tourchi, Ali; Ebadi, Maryam; Hosseinzadeh, Alireza; Shabaninia, Mahsa

    2014-03-01

    Haematogenous dissemination of undiagnosed urinary tuberculosis after performing extracorporeal shock-wave lithotripsy (ESWL) is extremely rare. Herein, we report a 41-year-old male who presented with urosepsis to the emergency room; catheterization was performed and retention resolved. He had a tattoo on his left arm and a five-year history of intravenous drug use. Blood tests indicated anaemia, leukocytosis, elevated CRP and ESR and mild hyponatraemia; haematuria, moderate bacteriuria and 2+ proteinuria on urinanalysis were observed. Chest X-ray revealed lesions suggestive of miliary tuberculosis, which was confirmed by chest CT scan. Brain CT and MRI suggested brain involvement in the setting of tuberculosis. On further investigations, HIV infection and hepatitis C seropositivity were detected and the patient remained in a coma for five days with a Glasgow Coma Scale of 6/15. Finally, the diagnosis of haematogenous dissemination of tuberculosis following lithotripsy was established. Anti-tuberculosis and anti-retroviral therapy were prescribed and monthly follow-up visits were scheduled. In conclusion, in a patient diagnosed with ureterolithiasis, a thorough history and physical examination, with specific attention to HIV and tuberculosis predisposing factors, should be carried out and preoperative screening tests considering the possibility of urinary tuberculosis are required. Finally, if urinary tuberculosis is detected, ESWL must be postponed until after appropriate treatment of tuberculosis. PMID:23970650

  4. In vitro study of the mechanical effects of shock-wave lithotripsy.

    PubMed

    Howard, D; Sturtevant, B

    1997-01-01

    Impulsive stress in repeated shock waves administered during extracorporeal shock-wave lithotripsy (ESWL) causes injury to kidney tissue. In a study of the mechanical input of ESWL, the effects of focused shock waves on thin planar polymeric membranes immersed in a variety of tissue-mimicking fluids have been examined. A direct mechanism of failure by shock compression and an indirect mechanism by bubble collapse have been observed. Thin membranes are easily damaged by bubble collapse. After propagating through cavitation-free acoustically heterogeneous media (liquids mixed with hollow glass spheres, and tissue) shock waves cause membranes to fail in fatigue by a shearing mechanism. As is characteristic of dynamic fatigue, the failure stress increases with strain rate, determined by the amplitude and rise time of the attenuated shock wave. Shocks with large amplitude and short rise time (i.e., in uniform media) cause no damage. Thus the inhomogeneity of tissue is likely to contribute to injury in ESWL. A definition of dose is proposed which yields a criterion for damage based on measurable shock wave properties. PMID:9330454

  5. The adoption and use of extracorporeal shock wave lithotripsy by hospitals in the United States.

    PubMed

    Power, E J

    1987-01-01

    Extracorporeal shock wave lithotripsy (ESWL) for upper urinary stones has been in use in the United States since 1984. It was accepted immediately by hospitals and physicians, and its diffusion has been and continues to be rapid. Government payment and planning policies do not seem to have slowed this diffusion, although they have had some effect on the ownership of lithotripters and the manner in which ESWL is provided. An unintended but foreseeable result of ESWL's popularity with hospitals, physicians, and patients is that ESWL is not only rapidly replacing traditional surgery but is being used on many patients who would not have had surgery. It is likely that many more upper urinary stones are being treated aggressively now than before ESWL was introduced. PMID:10285325

  6. Variables influencing radiation exposure during extracorporeal shock wave lithotripsy. Review of 298 treatments

    SciTech Connect

    Carter, H.B.; Naeslund, E.B.R.; Riehle, R.A. Jr.

    1987-12-01

    Retrospective review of 298 extracorporeal shock wave lithotripsy (ESWL) treatments was undertaken to determine the factors which influence radiation exposure during ESWL. Fluoroscopy time averaged 160 seconds (3-509), and the average number of spot films taken per patient was 26 (5-68). The average stone burden was 19.3 mm (3-64). Average calculated skin surface radiation exposure was 17.8 R per treatment. Radiation exposure increased with increasing stone burden and patient weight. Stones treated in the ureter resulted in a higher average patient radiation exposure than for renal stones (19 R vs 16 R), even though the average size of these ureteral stones (11.3 mm) was significantly less than the mean. However, type of anesthetic (general or regional) used was not a significant factor. Operator training, experience, and familiarity with radiation physics should significantly decrease the amount of imaging time and consequent patient radiation exposure during ESWL.

  7. A case of hyperreninemic hypertension after extracorporeal shock-wave lithotripsy.

    PubMed

    Sasaguri, M; Noda, K; Matsumoto, T; Shirai, K; Tsuji, E; Tsuji, Y; Arakawa, K

    2000-11-01

    A 53-year-old male was found to have hypertension caused by the significant secretion of renin from an atrophic left kidney. He had undergone extracorporeal shock-wave lithotripsy (ESWL) for left renal lithiasis 11 years previously. A renal dynamic study with 99mTc-diethylenetriaminepentaacetic acid (DTPA) indicated that the rate of renal excretion and uptake was decreased in the left kidney and normal in the right kidney. Renal angiography demonstrated a normal right renal artery and a small but nonstenotic left renal artery. The ratio of PRA in the left renal vein to that in the right renal vein was 1.7. Blood pressure could be lowered to the range of 140-150/80-90 mmHg with imidapril, an ACE inhibitor. ESWL may cause hypertension via the well-known Page kidney effect. In this case, the kidney, atrophic probably due to ESWL, released a significant amount of renin. PMID:11131285

  8. Kidney damage in extracorporeal shock wave lithotripsy: a numerical approach for different shock profiles.

    PubMed

    Weinberg, Kerstin; Ortiz, Michael

    2009-08-01

    In shock-wave lithotripsy--a medical procedure to fragment kidney stones--the patient is subjected to hypersonic waves focused at the kidney stone. Although this procedure is widely applied, the physics behind this medical treatment, in particular the question of how the injuries to the surrounding kidney tissue arise, is still under investigation. To contribute to the solution of this problem, two- and three-dimensional numerical simulations of a human kidney under shock-wave loading are presented. For this purpose a constitutive model of the bio-mechanical system kidney is introduced, which is able to map large visco-elastic deformations and, in particular, material damage. The specific phenomena of cavitation induced oscillating bubbles is modeled here as an evolution of spherical pores within the soft kidney tissue. By means of large scale finite element simulations, we study the shock-wave propagation into the kidney tissue, adapt unknown material parameters and analyze the resulting stress states. The simulations predict localized damage in the human kidney in the same regions as observed in animal experiments. Furthermore, the numerical results suggest that in first instance the pressure amplitude of the shock wave impulse (and not so much its exact time-pressure profile) is responsible for damaging the kidney tissue. PMID:18807077

  9. Extracorporeal shock wave lithotripsy in children: experience using a mpl-9000 lithotriptor.

    PubMed

    Aksoy, Yilmaz; Ozbey, Isa; Atmaca, Ali Fuat; Polat, Ozkan

    2004-06-01

    Our objectives were to assess the value of extracorporeal shock wave lithotripsy (ESWL) in treating pediatric urolithiasis, and to determine the factors that may affect treatment success. Between January 1993 and August 2002, 129 children with upper urinary tract calculi (134 renoureteral units) were treated using a Dornier MPL-9000 lithotriptor. The series consisted of 77 boys and 52 girls with an age range from 20 months to 14 years (average age: 8.7 years). All ESWL procedures took place under general anaesthesia or sedation with ketamin or fentanyl. Under ultrasonic or fluoroscopic guidance, children were treated with a maximum 2,550 shocks at an average of 19.5 kV. Success was defined as the lack of any visible stone fragments on post-treatment radiological evaluation. The patients were assessed 3 months after ESWL treatment and the results were compared using chi(2)-tests to detect factors that might be associated with treatment success. There were 105 renal, 20 ureteral, four bilateral renal and one unilateral renal plus contralateral ureteral calculi. The mean sizes were 15.7 mm for pelvic, 17.8 mm for renal and 10.2 mm for ureteral stones. One or two lithotripsy sessions were sufficient in most cases (71.6%). In 15 (11.6%) patients, double J stents introduced before lithotripsy were left indwelling until all stone fragments were voided. Overall success rates were 89.5% for pelvic, 85.5% for renal and 75% for ureteral stones. Complications such as urinary tract infection, Steinstrasse and small subcapsular hematoma occurred in 19 (14.7%) patients. The only significant factor associated with the stone-free rate was the diameter of the stone ( P=0.022). This study confirmed that the stone-free rate is significantly influenced by stone size. Because children with stone disease are at risk for a longer period than adults, their cumulative likelihood of stone recurrences may be higher. Thus, we agree with other authorities that minimally invasive treatment, such as ESWL, is mandatory in children with urolithiasis. PMID:14740160

  10. Anti-miss-shot control device for selective stone disintegration in extracorporeal shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Kuwahara, M.; Ioritani, N.; Kambe, K.; Orikasa, S.; Takayama, K.

    1991-06-01

    A new device to prevent erroneously focused shock waves to the renal parenchyma during extracorporeal shock wave lithotripsy (ESWL) has been developed; an anti-miss-shot control device (AMCD) and experiments have been conducted to evaluate its effectiveness. For shock wave generation and stone localization, piezoceramic elements (PSE) and ultrasound localization, respectively were used. After stone localization, probing ultrasounds (PU) were emmitted from the PSE towards the focal region and the reflected sound levels (RSL) were monitored by the PSE which also functioned as a microphone. A direct hit by the PU to the stone or a miss was judged from the RSL, i.e. a high RSL indicates a direct hit and a low RSL indicates a miss. Shock waves were generated only when the RSL exceeded the level which indicated a direct hit. The experimental results showed that the injury to the renal parenchyma was decreased by using the AMCD. Clinical application of the AMCD is expected to increase the safety of ESWL.

  11. Tissue damage in kidney, adrenal glands and diaphragm following extracorporeal shock wave lithotripsy.

    PubMed

    Gecit, Ilhan; Kavak, Servet; Oguz, Elif Kaval; Pirincci, Necip; Günes, Mustafa; Kara, Mikail; Ceylan, Kadir; Kaba, Mehmet; Tanık, Serhat

    2014-10-01

    This study was designed to investigate whether exposure to short-term extracorporeal shock wave lithotripsy (ESWL) produces histologic changes or induces apoptosis in the kidney, adrenal glands or diaphragm muscle in rats. The effect of shock waves on the kidney of male Wistar rats (n = 12) was investigated in an experimental setting using a special ESWL device. Animals were killed at 72 h after the last ESWL, and the tissues were stained with an in situ Cell Death Detection Kit, Fluorescein. Microscopic examination was performed by fluorescent microscopy. Apoptotic cell deaths in the renal tissue were not observed in the control group under fluorescent microscopy. In the ESWL group, local apoptotic changes were observed in the kidney in the area where the shock wave was focused. The apoptotic cell deaths observed in the adrenal gland of the control group were similar to those observed in the ESWL groups, and apoptosis was occasionally observed around the capsular structure. Apoptotic cell deaths in the diaphragm muscle were infrequently observed in the control group. Apoptosis in the ESWL group was limited to the mesothelial cells. This study demonstrated that serious kidney, adrenal gland and diaphragm muscles damage occurred following ESWL, which necessitated the removal of the organ in the rat model. It is recognized that the ESWL complications related to the kidney, adrenal gland and diaphragm muscles are rare and may be managed conservatively. PMID:23095486

  12. Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound.

    PubMed

    Wang, Jen-Chieh; Zhou, Yufeng

    2015-01-01

    Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve these bubbles for better stone comminution efficiency. In this study, low intensity pulsed ultrasound (LIPUS) beam was aligned perpendicular to the axis of a shock wave (SW) lithotripter at its focus. The light transmission was used to evaluate the compressive wave and cavitation induced by SWs without or with a combination of LIPUS for continuous sonication. It is found that bubble shielding effect becomes dominated with the SW exposure and has a greater significant effect on cavitation than compressive wave. Using the combined wave scheme, the improvement began at the 5th pulse and gradually increased. Suppression effect on bubble shielding is independent on the trigger delay, but increases with the acoustic intensity and pulse duration of LIPUS. The peak negative and integral area of light transmission signal, which present the compressive wave and cavitation respectively, using our strategy at PRF of 1 Hz are comparable to those using SW alone at PRF of 0.1 Hz. In addition, high-speed photography confirmed the bubble activities in both free field and close to a stone surface. Bubble motion in response to the acoustic radiation force by LIPUS was found to be the major mechanism of suppressing bubble shielding effect. There is a 2.6-fold increase in stone fragmentation efficiency after 1000 SWs at PRF of 1 Hz in combination with LIPUS. In summary, combination of SWs and LIPUS is an effective way of suppressing bubble shielding effect and, subsequently, improving cavitation at the focus for a better outcome. PMID:25173067

  13. Shock Wave Lithotripsy in Ureteral Stones: Evaluation of Patient and Stone Related Predictive Factors

    PubMed Central

    Yazici, Ozgur; Tuncer, Murat; Sahin, Cahit; Demirkol, Mehmet K.; Kafkasli, Alper; Sarica, Kemal

    2015-01-01

    ABSTRACT Purpose: To evaluate the patient and stone related factors which may influence the final outcome of SWL in the management of ureteral stones. Materials and Methods: Between October 2011 and October 2013, a total of 204 adult patients undergoing SWL for single ureteral stone sizing 5 to 15 mm were included into the study program. The impact of both patient (age, sex, BMI,) and stone related factors (laterality, location, longest diameter and density as CT HU) along with BUN and lastly SSD (skin to stone distance) on fragmentation were analysed by univariate and multivariate analyses. Results: Stone free rates for proximal and distal ureteral stones were 68.8% and 72.7%, respectively with no statistically significant difference between two groups (p=0.7). According to univariate and multivariate analyses, while higher BMI (mean: 26.8 and 28.1, p=0.048) and stone density values (mean: 702 HU and 930 HU, p<0.0001) were detected as statistically significant independent predictors of treatment failure for proximal ureteral stones, the only statistically significant predicting parameter for the success rates of SWL in distal ureteral stones was the higher SSD value (median: 114 and 90, p=0.012). Conclusions: Our findings have clearly shown that while higher BMI and increased stone attenuation values detected by NCCT were significant factors influencing the final outcome of SWL treatment in proximal ureteral stones; opposite to the literature, high SSD was the only independent predictor of success for the SWL treatment of distal ureteral stones. PMID:26401859

  14. Renal morphology and function immediately after extracorporeal shock-wave lithotripsy

    SciTech Connect

    Kaude, J.V.; Williams, C.M.; Millner, M.R.; Scott, K.N.; Finlayson, B.

    1985-08-01

    The acute effects of extracorporeal shock-wave lithotripsy (ESWL) on morphology and function of the kidney were evaluated by excretory urography, quantitative radionuclide renography (QRR), and magnetic resonance imaging (MRI) in 33 consecutive patients. Excretory urograms demonstrated an enlarged kidney in seven (18%) of 41 treatments and partial or complete obstruction of the ureter by stone fragments after 15 (37%) of 41 treatments. Total effective renal plasma flow (ERPF) was not changed after ESWL, but the percentage ERPF of the treated kidney was decreased by more than 5% in 10 (30%) of 33 cases. QRR images showed partial parenchymal obstruction in 10 (25%) of 41 teated kidneys and total parenchymal obstruction in 9 (22%). MRI disclosed one or more abnormalities in 24 (63%) of 38 treated kidneys. Treated kidneys were normal by all three imaging methods in 26% and abnormal by one or more tests in 74% of cases. The morphologic and functional changes are attributed to renal contusion resulting in edema and extravasation of urine and blood into the interstitial, subcapsular, and perirenal spaces.

  15. [Effects and side effects of ureteral stenting during extracorporeal shock wave lithotripsy].

    PubMed

    Kohri, K; Katayama, Y; Ishii, T; Kato, Y; Kurita, T; Mitsubayashi, S; Iguchi, M

    1990-10-01

    We retrospectively studied the effects and side effects of placing indwelling ureteral stents in 196 cases who underwent extracorporeal shock wave lithotripsy with a ureteral stent. The average period of ureteral stenting was approximately 22 days. Placing ureteral stents was mainly for large renal stones (79.3%), single kidney etc. There were no significant differences between the stunted and non-stunted patients with approximately 2 cm sized single renal stone with respect to the stone free rate, stone free period, and symptoms during stenting, which suggested that ureteral stenting might be unnecessary in those patients. High fever was highest in incidence of the symptoms and complications during stenting (17.2%). It occurred frequently in patients with infected stones or cystine stones. The percentages of pyrexia and stone street in patients using Towers type's stents were higher than those using the others. It was also shown that the bladder portions of the stents in patients using Towers peripheral ureteral stents were densely encased in calculous material and were very brittle. Fortunately the ureteral portions were removed intact. This study suggests that use of an indwelling ureteral stent may not contribute to the higher rate of being free of stones after the treatment of small to medium sized renal calculi, and that stents should be removed or changed early. PMID:2273707

  16. Can a dual-energy computed tomography predict unsuitable stone components for extracorporeal shock wave lithotripsy?

    PubMed Central

    Ahn, Sung Hoon; Oh, Tae Hoon

    2015-01-01

    Purpose To assess the potential of dual-energy computed tomography (DECT) to identify urinary stone components, particularly uric acid and calcium oxalate monohydrate, which are unsuitable for extracorporeal shock wave lithotripsy (ESWL). Materials and Methods This clinical study included 246 patients who underwent removal of urinary stones and an analysis of stone components between November 2009 and August 2013. All patients received preoperative DECT using two energy values (80 kVp and 140 kVp). Hounsfield units (HU) were measured and matched to the stone component. Results Significant differences in HU values were observed between uric acid and nonuric acid stones at the 80 and 140 kVp energy values (p<0.001). All uric acid stones were red on color-coded DECT images, whereas 96.3% of the nonuric acid stones were blue. Patients with calcium oxalate stones were divided into two groups according to the amount of monohydrate (calcium oxalate monohydrate group: monohydrate≥90%, calcium oxalate dihydrate group: monohydrate<90%). Significant differences in HU values were detected between the two groups at both energy values (p<0.001). Conclusions DECT improved the characterization of urinary stone components and was a useful method for identifying uric acid and calcium oxalate monohydrate stones, which are unsuitable for ESWL. PMID:26366277

  17. Impact of shock wave pattern and cavitation bubble size on tissue damage during ureteroscopic electrohydraulic lithotripsy.

    PubMed

    Vorreuther, R; Corleis, R; Klotz, T; Bernards, P; Engelmann, U

    1995-03-01

    It is known that electrohydraulic lithotripsy (EHL) during ureteroscopy may cause ureteral damage. To evaluate this trauma potential, find its mechanism and make it possible to avoid it, our research employed photographic evaluation, tissue studies, shock wave measurements and disintegration tests. The setup included a 3.3 F probe attached to an experimental generator with adjustable voltages and capacities providing energies from 25 mJ. to 1300 mJ. per pulse. In general, we distinguish between two traumatic mechanisms: (1) After placing the probe directly on the mucosa the rapid initial plasma penetrates the tissue resulting in a small, nonthermal, punched-like defect, whose depth depends on the energy applied. This trauma has minor clinical implications and is avoided by maintaining a minimum safety distance of 1 mm.; (2) According to physics, each plasma is followed by a cavitation bubble. The maximum size of this bubble depends on the energy applied and ranges from 3 mm. (25 mJ) to > 15 mm. (1300 mJ). In proportion to the bubble size, the ureteral wall may be distended or disrupted, even when the probe is not in direct contact with the mucosa. Therefore, the goal should be to obtain a low energy pressure pulse with high disintegration efficacy. Our evaluation of the pressure waves revealed that the selection of a high voltage and a low capacity leads to short and steep "laser-like" pulses. These pulses have a significant higher impact on stone disintegration than the broader pulses of the same energy provided by currently available generators. PMID:7861549

  18. A cumulative shear mechanism for tissue damage initiation in shock-wave lithotripsy

    PubMed Central

    Freund, Jonathan B.; Colonius, Tim; Evan, Andrew P.

    2007-01-01

    Evidence suggests that inertial cavitation plays an important role in the renal injury incurred during shock-wave lithotripsy. However, it is unclear how tissue damage is initiated, and significant injury typically occurs only after a sufficient dose of shock waves. While it has been suggested that shock-induced shearing might initiate injury, estimates indicate that individual shocks do not produce sufficient shear to do so. In this paper, we hypothesize that the cumulative shear of the many shocks is damaging. This mechanism depends upon whether there is sufficient time between shocks for tissue to relax to its unstrained state. We investigate the mechanism with a physics-based simulation model wherein the the basement membranes that define the tubules and vessels in the inner medulla are represented as elastic shells surrounded by viscous fluid. Material properties are estimated from in vitro tests of renal basement membranes and documented mechanical properties of cells and extracellular gels. Estimates for the net shear deformation from a typical lithotripter shock (~ 0.1%) are found from a separate dynamic shock simulation. The results suggest that the larger interstitial volume (~ 40%) near the papilla tip gives the tissue there a relaxation time comparable to clinical shock delivery rates (~ 1Hz), thus allowing shear to accumulate. Away from the papilla tip, where the interstitial volume is smaller (≲ 20%), the model tissue relaxes completely before the next shock would be delivered. Implications of the model are that slower delivery rates and broader focal zones should both decrease injury, consistent with some recent observations. PMID:17507147

  19. Effectiveness of extracorporeal shock wave lithotripsy on intrahepatic biliary calculi developing after choledochal cyst surgery: A case report.

    PubMed

    Şenyüz, Osman Faruk; Gülşen, Fatih; Gökhan, Okan; Emre, Şenol; Eroğlu, Egemen

    2015-05-01

    The development of intra- and extrahepatic bile duct stones has been reported as one of the most serious complications after choledochal cyst excision with biliary-enteric reconstruction through Roux-en-Y hepaticojejunostomy (HJ). Here, we report our experience with extracorporeal shock wave lithotripsy (ESWL) in a case of giant intrahepatic stones developing after choledochal cyst surgery. ESWL is an excellent therapeutic modality for large intrahepatic biliary calculi, and after dilating the HJ anastomosis percutaneously, it can be offered as first-line therapy to these patients. PMID:26006206

  20. Treatment Protocols to Reduce Injury and Improve Stone Breakage in SWL

    NASA Astrophysics Data System (ADS)

    McAteer, James A.; Evan, Andrew P.; Connors, Bret A.; Pishchalnikov, Yuri A.; Williams, James C.; Lingeman, James E.

    2008-09-01

    Here we provide a capsule summary of key observations showing that adverse effects can be reduced and stone breakage outcomes can be improved by the choice of the treatment protocol used in SWL. The take home message is—technique in lithotripsy can be used to significant advantage. SW-rate is key, and so is the sequence of SW delivery. Patient studies have shown that stone breakage is significantly improved at 60SW/min compared to a rate of 120SW/min, and laboratory experiments with pigs show that acute SWL injury to the kidney can be reduced dramatically by further slowing the SW firing rate to 30SW/min. The sequence of SW administration has a profound effect on the kidney, and renal injury is significantly reduced when the treatment protocol incorporates a priming dose of SW's followed by a brief pause before treatment is resumed. Continued developments in lithotripsy technology are welcome and will hopefully lead to improved SWL systems. Current experience suggests, however, that technology is not a substitute for expert technique, and attention to the fundamentals of SW delivery is essential to achieve the best possible outcomes regardless of the lithotripter at hand.

  1. Effect of the frequency of transcutaneous electrical nerve stimulation on analgesia during extracorporeal shock wave lithotripsy.

    PubMed

    Kararmaz, Alper; Kaya, Sedat; Karaman, Haktan; Turhanoglu, Selim

    2004-12-01

    In this prospective, randomised, sham controlled study, we set out to determine which transcutaneous electrical nerve stimulation (TENS) therapy modality (conventional vs acupuncture-like) is more effective as a supplementary analgesic regimen during extracorporeal shock wave lithotripsy (ESWL). Patients were prospectively randomised to one of three groups. In Group I (n=22), conventional TENS (impulse pattern: continuous at 80 Hz; intensity: 10-30 mA) was applied. In Group II (n=22) acupuncture-like TENS (impulse pattern: burst at 2 Hz; intensity: 15-50 mA) was applied. In Group III (n=22) (control group), stimulation was started at 1 mA and the intensity increased to no more than 10 mA until it produced a tickling sensation. Alfentanil was administered through a patient controlled analgesic device. Alfentanil consumption, hemodynamics and respiratory parameters, a 10-cm visual analogue pain scale, patient satisfaction, recovery and discharge times were evaluated. The consumption of alfentanil was significantly lower in Group I than in Groups II and III (P<0.0001). Pain scores were lower in Group I than in the other two groups (P<0.05). Patients in Group I were more satisfied with their analgesic medication than those in the other two groups (P<0.05). Both the time to an Aldrete score >8 and a modified post-anaesthetic discharge score >8 were significantly shorter in Group I (2.3+/-1.8, 49.1+/-14.6) than those of Groups II (4.6+/-2.2, 60.2+/-18.1) and III (4.9+/-2.8, 58.4+/-16.5) (P<0.0001 and P<0.05, respectively). We conclude that the use of conventional TENS is effective in decreasing the analgesic requirements and the incidence of alfentanil-related side effects during ESWL. PMID:15243722

  2. Diagnostic and prognostic role of computed tomography in extracorporeal shock wave lithotripsy complications

    PubMed Central

    Telegrafo, Michele; Carluccio, Davide Antonio; Rella, Leonarda; Ianora, Amato Antonio Stabile; Angelelli, Giuseppe; Moschetta, Marco

    2016-01-01

    Purpose: To evaluate the role of multidetector computed tomography (MDCT) in recognizing the complications of extracorporeal shock wave lithotripsy (ESWL) and providing a prognostic grading system for the therapeutic approach. Materials and Methods: A total of 43 patients who underwent ESWL because of urinary stone disease were assessed by 320-row MDCT examination before and after ESWL. Pre-ESWL CT unenhanced scans were performed for diagnosing stone disease. Post-ESWL CT scans were acquired before and after intravenous injection of contrast medium searching for peri-renal fluid collection or hyper-density, pyelic or ureteral wall thickening, blood clots in the urinary tract, peri- or intra-renal hematoma or abscess, active bleeding. A severity grading system of ESWL complications was established. Results: Patients were affected by renal (n = 36) or ureteral (n = 7) lithiasis. Post-ESWL CT examination detected small fluid collections and hyper-density of peri-renal fat tissue in 35/43 patients (81%), pyelic or ureteral wall thickening in 2/43 (4%), blood clots in the urinary tract in 9/43 (21%), renal abscesses or hematomas with a diameter of <2 cm in 10/43 (23%), large retroperitoneal collections in 3/43 (7%), active bleeding from renal vessels in 1/43 (2%). Mild complications were found in 30 cases; moderate in 9; severe in 4. The therapeutic choice was represented by clinical follow-up (n = 20), clinical and CT follow-up (n = 10), ureteral stenting (n = 9), drainage of large retroperitoneal collections (n = 3), and arterial embolization (n = 1). Conclusion: MDCT plays a crucial role in the diagnosis of urolithiasis and follow-up of patients treated with ESWL recognizing its complications and providing therapeutic and prognostic indications. PMID:27141186

  3. Treatment of renal stones in infants: comparing extracorporeal shock wave lithotripsy and mini-percutaneous nephrolithotomy.

    PubMed

    Zeng, Guohua; Jia, Jianye; Zhao, Zhijian; Wu, Wenqi; Zhao, Zhigang; Zhong, Wen

    2012-10-01

    The objective of the study is to compare the efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) and mini-percutaneous nephrolithotomy (MPCNL) in treating renal stones sizing 15-25 mm in infants <3 years. Forty-six infants with renal stones sizing 15-30 mm were treated by either ESWL (22 renal units in 22 infants) using Dornier compact delta lithotripter or MPCNL (25 renal units in 24 infants) using 14F-18F renal access under general anesthesia. The operation time, stone-free rate, re-treatment rate, and complications between the two groups were compared with the χ(2), Mann-Whitney U, and Student's t tests. No significant differences in mean age and stone size were observed between the two groups. The 1- and 3-month postoperative stone-free rates were 84 and 96% in MPCNL group and were 31.8 and 86.4% in ESWL group. The re-treatment and complication rates were significantly higher in ESWL group than in MPCNL group (50 vs. 12%, P = 0.004; 16.0 vs. 45.5%, P = 0.028). The stone recurrence rate was similar between the two groups. No significant changes of serum creatinine (Cr) level and glomerular filtration rate were observed in both groups. In conclusion, MPCNL is an effective and feasible alternative monotherapy for large renal stones (15-25 mm) in infants, with a higher stone-free rate and a lower complication rate when compared with ESWL. PMID:22580634

  4. Efficacy of Extracorporeal Shock Wave Lithotripsy in Pediatric and Adolescent Urolithiasis

    PubMed Central

    Jee, Joon Yeop; Kim, Soo Dong

    2013-01-01

    Purpose To retrospectively evaluate the efficacy of extracorporeal shock wave lithotripsy (ESWL) by age and current condition as a first-line treatment for pediatric and adolescent urolithiasis. Materials and Methods The computerized records of 55 children were retrospectively reviewed from March 1991 to July 2007. The children were below 18 years of age and had undergone ESWL monotherapy for urolithiasis. There were 36 boys (65.5%) and 19 girls (34.5%), with a mean age of 8.5 years (range, 0.5-18 years). There were 24 patients aged 7 years or less and 31 patients aged more than 7 years. Results The mean size of the stones was 9.48 mm (range, 4-22 mm). The overall success rate of ESWL was 90.9% (50 children). The mean number of ESWL sessions was 2.02 (range, 1-10). The mean number of ESWL sessions for the patient group aged 7 years or less was 1.16 (range, 1-2) and that for the patient group aged more than 7 years was 2.97 (range, 1-10; p=0.037). There was also a statistically significant difference in the mean number of ESWL sessions between the younger and older patients who needed general anesthesia (1.16 vs. 2.2 sessions, respectively; 0.042). Conclusions In the patient group aged 7 years or less, the number of ESWL sessions and the complication rate were comparable with those for endoscopic management. Thus, ESWL is an effective first-line treatment modality for patients aged less than 7 years. PMID:24363869

  5. Aortic valve streptococcus group B endocarditis post-extracorporeal shock wave lithotripsy

    PubMed Central

    Meidani, Mohsen; Taghavi, Mahboobeh; Abdar Esfahani, Morteza

    2013-01-01

    BACKGROUND Sub-acute left-sided bacterial endocarditis is a serious condition that may present with variable clinical manifestations. Its symptoms include both sterile and infected emboli, and various immunological phenomena. CASE REPORT This report presents a 55 year old man with frequency and dysuria after a lithotripsy and several admissions with urosepsis. Due to the suspicion of infective endocarditis echocardiography was done which confirmed streptococcus group B endocarditis. CONCLUSION Streptococci group B is one of the rare causes of infective endocarditis, but it was observed after various producers such as lithotripsy. PMID:24302939

  6. Dual pulses for cavitation control in lithotripsy: Shock wave-bubble interactions and bioeffects

    NASA Astrophysics Data System (ADS)

    Sokolov, Dahlia L.

    2002-08-01

    Cavitation, the growth and collapse of gas/vapor bubbles, appears to play an important role in both stone comminution and tissue injury during shock wave lithotripsy, the clinical treatment in which focused, high amplitude shock pulses are used to comminute kidney stones. The goal of this research was to characterize in vitro cavitation activity and stone and cell damage in a novel system that uses converging dual pulses, produced by two identical, confocal lithotripters, to modify the cavitation field. The cavitation bubble dynamics were numerically calculated, and experiments were performed in a research electrohydraulic shock wave lithotripter to determine bubble size, lifetime, and pit depth created in aluminum foils by cavitation collapse. Furthermore, damage to model stones and to red blood cells was measured for both single and dual-pulses. A single shock pulse creates a ˜15 x 100 mm cloud of bubbles in water. The greatest cavitation activity and stone damage from single-pulses was found to occur 2 cm proximal to the geometric focus, F2, where the stone is normally aligned. Therefore, a 2 cm shift in stone alignment may potentially improve stone comminution and reduce tissue injury in clinical treatment. The dual-pulse lithotripter, on the other hand, generates a localized and intensified cavitation field that increased stone comminution efficiency at F2 by at least three times the maximum values achieved by single-pulses. At F2, acoustic pressure approximately doubled, as did bubble size, collapse time, and pit depth on foils. A significant reduction in comminution of stones suspended in glycerol indicates that cavitation activity, not the doubling of acoustic pressure, explains the increased comminution. On either side of F2, the second delayed pulse mitigated bubble collapse, resulting in little or no pitting on foils and reduced hemolysis, even when compared with single pulses. Numerical calculations of radial dynamics agreed with experimental findings. No significant bubble translation was observed or calculated. The data support the conclusion that cavitation plays an important role in efficient stone comminution and hemolysis. The dual-pulse lithotripter, because of its localized and intensified cavitation field, yields the promise of improved stone comminution efficiency, reduced tissue damage, and accelerated treatment.

  7. Shock wave-bubble interaction near soft and rigid boundaries during lithotripsy: numerical analysis by the improved ghost fluid method

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kazumichi; Kodama, Tetsuya; Takahira, Hiroyuki

    2011-10-01

    In the case of extracorporeal shock wave lithotripsy (ESWL), a shock wave-bubble interaction inevitably occurs near the focusing point of stones, resulting in stone fragmentation and subsequent tissue damage. Because shock wave-bubble interactions are high-speed phenomena occurring in tissue consisting of various media with different acoustic impedance values, numerical analysis is an effective method for elucidating the mechanism of these interactions. However, the mechanism has not been examined in detail because, at present, numerical simulations capable of incorporating the acoustic impedance of various tissues do not exist. Here, we show that the improved ghost fluid method (IGFM) can treat shock wave-bubble interactions in various media. Nonspherical bubble collapse near a rigid or soft tissue boundary (stone, liver, gelatin and fat) was analyzed. The reflection wave of an incident shock wave at a tissue boundary was the primary cause for the acceleration or deceleration of bubble collapse. The impulse that was obtained from the temporal evolution of pressure created by the bubble collapse increased the downward velocity of the boundary and caused subsequent boundary deformation. Results of this study showed that the IGFM is a useful method for analyzing the shock wave-bubble interaction near various tissues with different acoustic impedance.

  8. EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AND ENDOSCOPIC URETERAL STENT PLACEMENT IN AN ASIAN SMALL-CLAWED OTTER (AONYX CINEREA) WITH NEPHROLITHIASIS.

    PubMed

    Wojick, Kimberlee B; Berent, Allyson C; Weisse, Chick W; Gamble, Kathryn C

    2015-06-01

    Urolithiasis is a significant disease concern in Asian small-clawed otters (Aonyx cinerea), with over 60% of captive animals affected. Bilateral ureteral stent placement, using endoscopic and fluoroscopic guidance, and extracorporeal shock wave lithotripsy (ESWL) were performed as salvage procedures in a 13-yr-old intact female Asian small-clawed otter following a 7-yr history of nephrolithiasis and progressive renal insufficiency. Following the procedure, radiographs revealed a slight shifting of urolith position, although a decrease in urolith mass was not observed. As a result of declining quality of life related to severe osteoarthritis, the otter was euthanized 5 wk after the procedure. While this treatment approach was unsuccessful in this case, the technique was clinically feasible, so ESWL and ureteral stent placement may remain a consideration for other individuals of this species presented earlier in the course of this disease. PMID:26056891

  9. Treatment of renal uric acid stone by extracorporeal shock wave lithotripsy combined with sodium bicarbonate: 2 case reports.

    PubMed

    Li, Hao-Yong; Lian, Pei-Yu; Zhou, Zhi-Yan; Song, Peng; Yan, Yi; Liu, Ji-Hong

    2015-01-01

    Uric acid stone is the most comment radiolucent renal stone with high recurrence rate, which would further cause acute upper urinary tract obstruction and kidney failure. Here we report two cases of renal uric acid stone from December 2012 to April 2013. One 43-year-old male patient suffered from chronic uric acid nephrolithiasis caused by the long-term indwelling of bilateral double-J stent. Another 69-year-old patient was also diagnosed with uric acid nephrolithiasis at the right kidney. Both patients were first treated with extracorporeal shock wave lithotripsy (ESWL), followed by 1.5% sodium bicarbonate dissolution therapy. After a week of the treatment, the uric acid stones in both patients were completely dissolved without retrograde infection. In summary, the use of ESWL and sodium bicarbonate dissolution therapy as a combined modality is a safe, effective, inexpensive treatment for uric acid nephrolithiasis. PMID:26550383

  10. Treatment of renal uric acid stone by extracorporeal shock wave lithotripsy combined with sodium bicarbonate: 2 case reports

    PubMed Central

    Li, Hao-Yong; Lian, Pei-Yu; Zhou, Zhi-Yan; Song, Peng; Yan, Yi; Liu, Ji-Hong

    2015-01-01

    Uric acid stone is the most comment radiolucent renal stone with high recurrence rate, which would further cause acute upper urinary tract obstruction and kidney failure. Here we report two cases of renal uric acid stone from December 2012 to April 2013. One 43-year-old male patient suffered from chronic uric acid nephrolithiasis caused by the long-term indwelling of bilateral double-J stent. Another 69-year-old patient was also diagnosed with uric acid nephrolithiasis at the right kidney. Both patients were first treated with extracorporeal shock wave lithotripsy (ESWL), followed by 1.5% sodium bicarbonate dissolution therapy. After a week of the treatment, the uric acid stones in both patients were completely dissolved without retrograde infection. In summary, the use of ESWL and sodium bicarbonate dissolution therapy as a combined modality is a safe, effective, inexpensive treatment for uric acid nephrolithiasis. PMID:26550383

  11. Evaluation of Hounsfield Units as a predictive factor for the outcome of extracorporeal shock wave lithotripsy and stone composition.

    PubMed

    Nakasato, Takehiko; Morita, Jun; Ogawa, Yoshio

    2015-02-01

    The objective of this study was to evaluate the utility of the Hounsfield Unit (HU) values as a predictive factor of extracorporeal shock wave lithotripsy outcome for ureteral and renal stones. We also assessed the possibility that HU values could be used to predict stone composition. A retrospective study was performed to measure stone HU values in 260 patients who underwent extracorporeal shock wave lithotripsy (ESWL) for solitary renal and ureteral stones from July 2007 to January 2012. Stone volume, location, skin-to-stone distance, stone HU values, and stone composition were assessed. Success of ESWL was defined as: (1) being stone-free or (2) residual stone fragments <4 mm after 3 months by radiography. Of the 260 assessed patients, 141 (54.2%) were stone-free, 32 (12.3%) had residual stone fragments <4 mm (clinically insignificant stone fragments), and 87 (33.5%) had residual stone fragments ≥4 mm after one round of ESWL. Multivariate analysis revealed that stone location and mean HU were significant predictors of ESWL success. Receiver operating characteristic curves defined cutoff values for predicting treatment outcome. Treatment success rates were significantly higher for stones <815 HU than with stones >815 HU (P < 0.0265). HU of calcium oxalate and calcium phosphate stones were higher than those of uric acid stones, but we could not differentiate between calcium oxalate monohydrate and calcium oxalate dihydrate stones. Evaluation of stone HU values prior to ESWL can predict treatment outcome and aid in the development of treatment strategies. PMID:25139151

  12. Aggressive extracorporeal shock wave lithotripsy of gall bladder stones within wider treatment criteria: fragmentation rate and early results.

    PubMed Central

    Meiser, G; Heinerman, M; Lexer, G; Boeckl, O

    1992-01-01

    Two hundred and twenty patients with a total of 412 gall bladder stones of between 8 and 38 mm in size were treated with extracorporeal shock wave lithotripsy, using the overhead module Lithostrar Plus. Fifty six per cent of stones were solitary (mean (SD) diameter 23 (5) mm) and 9.5% of the patients had more than three stones. Stones were successfully disintegrated in 218 patients (fragmentation size less than 5 mm in 80%, less than 10 mm in 19%). Some 65% of patients required one treatment and the rest two or three. A mean (SD) of 4100 (1800) shock waves with a pressure of 700 bar were applied. Twenty four to 48 hours after lithotripsy a transient but significant increase in serum transaminase activities (31%) and in bilirubin (29%), urinary amylase (27%), and blood leukocyte (62%) values was observed. In 29% of patients there was a transient microhaematuria, in 2% transient macrohaematuria, and in 25% painless petechiae of the skin. Ultrasound showed temporary gall bladder wall oedema in 13%, temporary distension of the gall bladder in 11%, and transient common bile duct distension in 8% after treatment. After discharge from hospital, 31% of patients complained of recurrent colic that responded to simple analgesics. Four to eight weeks after therapy, four patients developed biliary pancreatitis and 11 biliary obstruction that was managed by endoscopy. To date, 105 patients have been followed for over 12 months. Sixty one of these had a solitary stone, 17 had two, and 27 had three or more stones. A total of 59 patients, including 44 with a primary solitary stone, eight with two stones, and seven with three or more stones are completely stone free. Images Figure 1 Figure 2 Figure 3 PMID:1371761

  13. Ulnar nerve neuropraxia after extracorporeal shock wave lithotripsy: a case report

    PubMed Central

    Konczak, Clark R

    2005-01-01

    A case is presented that illustrates and discusses the clinical presentation, diagnosis and chiropractic management of a 50-year-old male presenting with a case of ulnar neuropraxia following extracorporal shockwave lithotripsy. Onset is believed to be due to the patient’s arm position in full abduction and external rotation during the lithotripsy procedure. Motor abnormalities related to the ulnar nerve were noted in the absence of distinct sensory findings. Chiropractic treatment focused on relief of the patient’s pain during the course of the condition. Treatment may have helped in the rapid and complete resolution of his symptoms in this case. Poor patient positioning on hard surfaces, for extended periods may place pressure on superficial nerves resulting in nerve injury. In this case, the outcome was excellent, with complete resolution of symptoms less than one week later. The prognosis for this type of neuropraxia is usually good with conservative management. The patient history and chronological clinical course strongly suggest a causal association between the patient’s position during the procedure and the development of the ulnar neuropraxia. PMID:17549150

  14. Treatment of staghorn calculi by percutaneous nephrolithotomy and SWL: the Hotel Dieu de France experience.

    PubMed

    Merhej, S; Jabbour, M; Samaha, E; Chalouhi, E; Moukarzel, M; Khour, R; Chaiban, R

    1998-02-01

    To evaluate the combined approach of percutaneous nephrolithotomy (PCNL) and extracorporeal shockwave lithotripsy (SWL) in the treatment of staghorn calculi, we carried out a retrospective review of 101 patients. The stone surface area ranged from 654 to 3042 mm2 (1535 mm2 on average). During PCNL, a single access tract was used in 22 patients, a double tract in 65 patients, and a triple tract in 14 patients. A double-J stent was placed percutaneously in 62 patients. Extracorporeal lithotripsy was scheduled at the patient's convenience on an outpatient basis approximately 2 weeks after PCNL. The mean hospital stay was 4.4 days. The combined approach showed a stone-free rate of 67% on the initial evaluation, an insignificant residual fragment rate of 26%, and a residual stone rate of 7%. With a follow-up of 52 months on average, the global stone growth rate was 17%, being 4.4% only among the stone-free group and 27% among the group with insignificant residual fragments. The global transfusion rate was 10%. Percutaneous stone debulking combined with SWL on an outpatient basis is an efficient, minimally invasive treatment for staghorn renal calculi. Reducing the number of access tracts, using the flexible nephroscope liberally, and placing a double-J stent frequently after PCNL increases the stone-free rate while reducing the morbidity and hospital stay. PMID:9531142

  15. Shock-induced bubble jetting into a viscous fluid with application to tissue injury in shock-wave lithotripsy

    PubMed Central

    Freund, J. B.; Shukla, R. K.; Evan, A. P.

    2009-01-01

    Shock waves in liquids are known to cause spherical gas bubbles to rapidly collapse and form strong re-entrant jets in the direction of the propagating shock. The interaction of these jets with an adjacent viscous liquid is investigated using finite-volume simulation methods. This configuration serves as a model for tissue injury during shock-wave lithotripsy, a medical procedure to remove kidney stones. In this case, the viscous fluid provides a crude model for the tissue. It is found that for viscosities comparable to what might be expected in tissue, the jet that forms upon collapse of a small bubble fails to penetrate deeply into the viscous fluid “tissue.” A simple model reproduces the penetration distance versus viscosity observed in the simulations and leads to a phenomenological model for the spreading of injury with multiple shocks. For a reasonable selection of a single efficiency parameter, this model is able to reproduce in vivo observations of an apparent 1000-shock threshold before wide-spread tissue injury occurs in targeted kidneys and the approximate extent of this injury after a typical clinical dose of 2000 shock waves. PMID:19894850

  16. Simulation of shock-induced bubble collapse with application to vascular injury in shockwave lithotripsy

    NASA Astrophysics Data System (ADS)

    Coralic, Vedran

    Shockwave lithotripsy is a noninvasive medical procedure wherein shockwaves are repeatedly focused at the location of kidney stones in order to pulverize them. Stone comminution is thought to be the product of two mechanisms: the propagation of stress waves within the stone and cavitation erosion. However, the latter mechanism has also been implicated in vascular injury. In the present work, shock-induced bubble collapse is studied in order to understand the role that it might play in inducing vascular injury. A high-order accurate, shock- and interface-capturing numerical scheme is developed to simulate the three-dimensional collapse of the bubble in both the free-field and inside a vessel phantom. The primary contributions of the numerical study are the characterization of the shock-bubble and shock-bubble-vessel interactions across a large parameter space that includes clinical shockwave lithotripsy pressure amplitudes, problem geometry and tissue viscoelasticity, and the subsequent correlation of these interactions to vascular injury. Specifically, measurements of the vessel wall pressures and displacements, as well as the finite strains in the fluid surrounding the bubble, are utilized with available experiments in tissue to evaluate damage potential. Estimates are made of the smallest injurious bubbles in the microvasculature during both the collapse and jetting phases of the bubble's life cycle. The present results suggest that bubbles larger than one micrometer in diameter could rupture blood vessels under clinical SWL conditions.

  17. [Conservative treatment of severe renal trauma after extracorporeal shockwave lithotripsy].

    PubMed

    Marchini, Giovanni Scala; Lopes, Roberto Iglesias; Bruschini, Homero; Torricelli, Fábio; Lopes, Roberto Nicomedes

    2011-01-01

    Subcapsular and perinephric hematomas are relatively common after shock-wave lithotripsy, but high-grade kidney injuries are extremely rare. We present the first case of a high-grade kidney injury after shock-wave lithotripsy managed conservatively. A 57-year-old white female patient with left 1.5cm superior ureteral calculi was submitted to shock-wave lithotripsy. PMID:22267146

  18. Treatment of Kidney Stones Using Extracorporeal Shock Wave Lithotripsy (ESWL) and Double-J Stent in Infants.

    PubMed

    Younesi Rostami, Mehdi; Taghipour-Gorgikolai, Mehrdad; Sharifian, Rayka

    2012-01-01

    Background. Extracorporeal shock wave lithotripsy (ESWL) has progressively acquired popularity as being the gold standard treatment for upper urinary tract lithiasis in infants since 1980. Our aim was to evaluate the outcome of ESWL for kidney stones and the use of double-J stent in infants. Material and Methods. A prospective clinical trial study performed on 50 infants with renal calculi at pelvic admitted in the Urology ward of Shafa Hospital, Sari, Iran, between 2001 and 2010. Main outcome measure of our study was clearing stones after one or more consecutive sessions of ESWL. Results. The study included 50 patients with renal calculi at pelvic. Among them, there were 35 (70%) boys and 15 (30%) girls with the age ranging from 1 to 13 months (mean of 7 month ± 3 days). All of them were treated by standard ESWL using Simons Lithostor plus machine. The stone sizes ranged from 6 mm to 22 mm. Double-J stents were placed in 11 infants (22%) with stones larger than 13 mm. Most of the patients required only one ESWL session. Conclusion. Since there were no complications following ESWL treatment, we can conclude that, in short term, ESWL is an effective and safe treatment modality for renal lithiasis in infants. In addition, we recommend double-J stent in infants with stones larger than 13 mm. PMID:22550483

  19. Topical EMLA for pain control during extracorporeal shock wave lithotripsy: prospective, comparative, randomized, double-blind study.

    PubMed

    Gallego Vilar, D; García Fadrique, G; Di Capua Sacoto, C; Beltran Persiva, J; Perez Mestre, M; De Francia, J A; Povo Martin, I; Miralles Aguado, J; Garau Perelló, C; Sanchis Verdu, L; Gallego Gomez, J

    2012-10-01

    Patient collaboration in external shock wave lithotripsy (ESWL) is critical for its correct application, making proper analgesic selection indispensable. The aim of this study was to evaluate the efficacy of combined application of EMLA and intravenous (i.v.) pethidine compared with pethidine plus placebo cream in patients undergoing ESWL for ureteral and/or renal lithiasis. Prospective, controlled, randomized, double-blind study was conducted in patients receiving ESWL for renal and/or ureterolithiasis. The patients were randomly assigned to receive i.v. pethidine plus either EMLA cream (group A) or placebo hydrating cream (group B). Evaluated were type, location, and size of lithiasis, patient's sex, age, body mass index, comorbidity, Visual Analogue Scale (VAS) score of pain, and degree of lithiasis fragmentation. EMLA cream provided significantly better pain relief and lithiasis fragmentation and more completed ESWL treatment. Topical application of EMLA cream combined with i.v. pethidine improved VAS scores and lithiasis fragmentation and decreased the rate of withdrawal from ESWL procedure versus i.v. pethidine plus placebo therapy. PMID:22555869

  20. A novel method to control P+/P- ratio of the shock wave pulses used in the extracorporeal piezoelectric lithotripsy (EPL).

    PubMed

    Lewin, P A; Chapelon, J Y; Mestas, J L; Birer, A; Cathignol, D

    1990-01-01

    There is growing evidence that acoustic cavitation plays an important role in stone fragmentation during extracorporeal shock wave lithotripsy (ESL) treatment. In addition, side effects of the treatment, such as the hemorrhage and destruction of the tissue in the vicinity of the stone are also ascribed to cavitation phenomenon. Since cavitation is associated with the maximum negative pressure in the shock pulse, it would thus appear that possibility of controlling this pressure would be desirable in ESL applications. This paper describes a novel technique developed to control the ratio of compressional peak (P+) to rarefactional peak pressure (P-) of the shock wave for use in lithotripsy treatment. The procedure is based on the finite amplitude wave generation by focused piezoelectric transducers and subsequent interaction of the shocked waves in the common focal region. The highly asymmetrical shock wave is produced in the focal region by providing an appropriate time delay to each of the high voltage electrical excitation signals which drive the transducers. The degree of relative reduction of negative halfcycles and the corresponding positive halfcycles amplification increases with the number of the acoustic sources used. The practical implementation of the shock wave generator was obtained by using 5 cm diameter, focused 1 MHz transmitter, and additional transducers of identical construction having frequencies corresponding to the harmonics and subharmonics of the 1 MHz frequency. The importance of the results for the future development of lithotripters, and stone treatment efficiency is pointed out. PMID:2238254

  1. Evaluation of a system for classification of stones and their sites in kidneys treated with extracorporeal shock wave lithotripsy.

    PubMed

    Pettersson, B; Tiselius, H G; Rahmqvist, M

    1990-01-01

    The results of treatment with extracorporeal shock wave lithotripsy (ESWL) were recorded in 1067 patients with renal calculi during their first admission to hospital. All treatments were performed in an unmodified Dornier HM3 lithotripter according to the original recommendations whereby the generator voltage was usually set between 18 and 23 kV. The stones in kidneys treated with ESWL alone were first classified into four different types (A. B. C. D) and after which a further subgrouping was carried out according to the number and sites of stones in the renal pelvis or calyces. The number of shock-waves. the energy index. the duration of treatment, and length of hospital stay as well as the therapeutic results after four weeks and six months were recorded for the different subgroups. An approximate estimate of the stone volume was calculated from measurements on a plain abdominal radiograph. The mean stone volume, number of shock waves, energy index, duration of treatment, and length of hospital stay increased progressively and significantly from group A to group D. The stone volumes and the energy indexes in the different subgroups within each type were distributed around levels that clearly differed between the types. Although minor variations were observed similar patterns also were recorded for the retreatment rate, the total duration of treatment, and the length of hospital stay. The therapeutic result, expressed as satisfactory disintegration, showed roughly similar results within each group but, as expected, the success rate decreased when more complicated stones were treated. Although stones located in the renal pelvis were often bigger than calyceal stones, the former seemed to disintegrate more easily.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2274754

  2. A Case of Septic Shock caused by Achromobacter xylosoxidans in an Immunocompetent Female Patient after Extracorporeal Shock Wave Lithotripsy for a Ureteral Stone

    PubMed Central

    Lee, So Yon; Park, In Young; Park, So Yeon; Lee, Jin Seo; Kang, Goeun; Kim, Jae Seok

    2016-01-01

    Achromobacter xylosoxidans can cause various types of infections, but its infection in humans is rare. A. xylosoxidans has been reported as a rare etiological agent of infections including primary bacteremia, catheter-related bloodstream infection, endocarditis, otitis, and pneumonia, particularly in immunocompromised hosts. We encountered a case of septic shock caused by A. xylosoxidans in a 52-year-old, immunocompetent woman with no underlying disease, who received extracorporeal shock wave lithotripsy to remove a left upper ureteral stone. She was treated with antibiotics to which the organism was susceptible but died as a result of septic shock. PMID:27104016

  3. Extracorporeal lithotripsy. Update on technology.

    PubMed

    Chow, G K; Streem, S B

    2000-05-01

    The development of shock-wave lithotripsy was a serendipitous event. Fortunately, the significance of this accidental discovery was not overlooked by the engineers at Dornier and their medical counterparts. There are many components that make up a lithotripter, but the heart of the lithotripter is its energy source. These machines often are categorized by the type of shock-wave generator used, and each type of generator has its own advantages and disadvantages. Unfortunately, no quantitative value of a shock-wave generator can be correlated to its qualitative effect. Interestingly, each type of energy source delivers its shock-wave energy with such distinctiveness that even the crater pattern it leaves in a stone is unique. New technology and ideas have transformed lithotripters in form and function so that they bear little resemblance to the original HM-1 prototype. Ongoing research is attempting to improve ESWL in several different ways, and advances in shock-wave generation, shock-wave measurement, and stone localization should result in even more efficient lithotripsy. The application of the time-reversal process to lithotripsy ultimately may enable lithotripters to track stones and electronically steer shock waves toward the target. Advances like these herald a time when ESWL, fortunately or unfortunately, will become automated completely. PMID:10778473

  4. [Research on Energy Distribution During Osteoarthritis Treatment Using Shock Wave Lithotripsy].

    PubMed

    Zhang, Shinian; Wang, Xiaofeng; Zhang, Dong

    2015-04-01

    Extracorporeal shock wave treatment is capable of providing a non-surgical and effective treatment modality for patients suffering from osteoarthritis. The major objective of current works is to investigate how the shock wave (SW) field would change if a bony structure exists in the path of the acoustic wave. Firstly, a model of finite element method (FEM) was developed based on Comsol software in the present study. Then, high-speed photography experiments were performed to record cavitation bubbles with the presence of mimic bone. On the basis of comparing experimental with simulated results, the effectiveness of FEM model could be verified. Finally, the energy distribution during extracorporeal shock wave treatment was predicted. The results showed that the shock wave field was deflected with the presence of bony structure and varying deflection angles could be observed as the bone shifted up in the z-direction relative to shock wave geometric focus. Combining MRI/CT scans to FEM modeling is helpful for better standardizing the treatment dosage and optimizing treatment protocols in the clinic. PMID:26211244

  5. Modeling and experimental analysis of acoustic cavitation bubbles for Burst Wave Lithotripsy

    PubMed Central

    Maeda, Kazuki; Colonius, Tim; Kreider, Wayne; Maxwell, Adam; Cunitz, Bryan; Bailey, Michael

    2016-01-01

    A combined modeling and experimental study of acoustic cavitation bubbles that are initiated by focused ultrasound waves is reported. Focused ultrasound waves of frequency 335 kHz and peak negative pressure 8 MPa are generated in a water tank by a piezoelectric transducer to initiate cavitation. The resulting pressure field is obtained by direct numerical simulation (DNS) and used to simulate single bubble oscillation. The characteristics of cavitation bubbles observed by high-speed photography qualitatively agree withs the simulation result. Finally, bubble clouds are captured using acoustic B-mode imaging that works in synchronization with high-speed photography. PMID:27087826

  6. Proteus mirabilis viability after lithotripsy of struvite calculi

    NASA Astrophysics Data System (ADS)

    Prabakharan, Sabitha; Teichman, Joel M. H.; Spore, Scott S.; Sabanegh, Edmund; Glickman, Randolph D.; McLean, Robert J. C.

    2000-05-01

    Urinary calculi composed of struvite harbor urease-producing bacteria within the stone. The photothermal mechanism of holmium:YAG lithotripsy is uniquely different than other lithotripsy devices. We postulated that bacterial viability of struvite calculi would be less for calculi fragmented with holmium:YAG irradiation compared to other lithotripsy devices. Human calculi of known struvite composition (greater than 90% magnesium ammonium phosphate hexahydrate) were incubated with Proteus mirabilis. Calculi were fragmented with no lithotripsy (controls), or shock wave, intracorporeal ultrasonic, electrohydraulic, pneumatic, holmium:YAG or pulsed dye laser lithotripsy. After lithotripsy, stone fragments were sonicated and specimens were serially plated for 48 hours at 38 C. Bacterial counts and the rate of bacterial sterilization were compared. Median bacterial counts (colony forming units per ml) were 8 X 106 in controls and 3 X 106 in shock wave, 3 X 107 in ultrasonic, 4 X 105 in electrohydraulic, 8 X 106 in pneumatic, 5 X 104 in holmium:YAG and 1 X 106 in pulsed dye laser lithotripsy, p less than 0.001. The rate of bacterial sterilization was 50% for holmium:YAG lithotripsy treated stones versus 0% for each of the other cohorts, p less than 0.01. P. mirabilis viability is less after holmium:YAG irradiation compared to other lithotripsy devices.

  7. Overview of shock waves in medicine

    NASA Astrophysics Data System (ADS)

    Cleveland, Robin O.

    2003-10-01

    A brief overview of three applications of shock waves is presented. Shock wave lithotripsy (SWL) has been in clinical use for more than 20 years. In the United States it is used to treat more than 80% of kidney stone cases and has wide acceptance with patients because it is a noninvasive procedure. Despite SWLs enormous success there is no agreement on how shock waves comminute stones. There is also a general acceptance that shock waves lead to trauma to the soft tissue of the kidney. Yet there has been little forward progress in developing lithotripters which provide comminution with less side-effects, indeed the original machine is still considered the gold standard. The last decade has seen the advent of new shock wave devices for treating principally musculoskeletal indications, such as plantar fasciitis, tennis elbow, and bone fractures that do not heal. This is referred to as shock wave therapy (SWT). The mechanisms by which SWT works are even less well understood than SWL and the consequences of bioeffects have also not been studied in detail. Shock waves have also been shown to be effective at enhancing drug delivery into cells and assisting with gene transfection. [Work partially supported by NIH.

  8. The clinical efficacy of extracorporeal shock wave lithotripsy in pediatric urolithiasis: a systematic review and meta-analysis.

    PubMed

    Lu, Pei; Wang, Zijie; Song, Rijin; Wang, Xiaolan; Qi, Kai; Dai, Qiying; Zhang, Wei; Gu, Min

    2015-06-01

    The aim was to investigate the clinical efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) in pediatric urolithiasis. A comprehensive systematic review and meta-analysis were performed. PubMed, Embase, and the Cochrane central register of controlled trials (CENTRAL) were searched, and the stone-free rates (SFRs) of various stone sizes and stone positions were extracted from the eligible articles. The quality of the original articles was assessed according to the McHarm Scale. The risk ratios (RRs) and 95% confidential intervals (CIs) were pooled, and the sensitive analysis was performed to evaluate the heterogeneity among all eligible studies. In total, 14 studies with 1842 patients were identified. The pooled RR for the SFR of stones less than 10 mm and greater than 10 mm was 1.14 (95% CI: 1.07, 1.21, P < 0.001); the RR for the SFR of stones in the renal pole calix (PC) and the renal pelvis was 0.95 (95% CI: 0.893, 1.009, P < 0.01); the RR for the SFR of stones in the upper/middle PC and the lower PC was 1.07 (95% CI: 0.997, 1.156, P < 0.061); and the RR for the SFR of stones in the proximal ureter and middle/distal ureter was 1.077 (95% CI: 1.005, 1.154, P = 0.036). Heterogeneity was low in all the analyses. Major complications in ESWL of pediatric urolithiasis were steinstrasse and abdominal colic, the incidences of which were 6.00 and 6.29 %, respectively. The SFR of stones <10 mm was significantly higher than stones >10 mm, and the SFR of stones located in proximal ureter was statistically greater than stones in middle or distal ureter in pediatric urolithiasis, leaving no significant between stones in renal PC and renal pelvis, or between upper/middle PC and lower PC. The use of ESWL in children is highly efficient, with negligible complications; ESWL therapy could be considered the first-line treatment for pediatric urolithiasis. PMID:25721456

  9. Modeling and experimental analysis of acoustic cavitation bubbles for Burst Wave Lithotripsy

    NASA Astrophysics Data System (ADS)

    Maeda, Kazuki; Kreider, Wayne; Maxwell, Adam; Cunitz, Bryan; Colonius, Tim; Bailey, Michael

    2015-12-01

    Cavitation bubbles initiated by focused ultrasound waves are investigated through experiments and modeling. Pulses of focused ultrasound with a frequency of 335 kHz and a peak negative pressure of 8 MPa is generated in a water tank by a piezoelectric transducer to initiate cavitation. The pressure field is modeled by solving the Euler equations and used to simulate single bubble oscillation. The characteristics of cavitation bubbles observed by highspeed photography qualitatively agree with the simulation results. Finally, bubble clouds are captured using acoustic B-mode imaging that works synchronized with high-speed photography.

  10. A comparative study to analyze the efficacy and safety of flexible ureteroscopy combined with holmium laser lithotripsy for residual calculi after percutaneous nephrolithotripsy

    PubMed Central

    Xu, Gang; Wen, Jiaming; Li, Zhongyi; Zhang, Zhewei; Gong, Xiuqing; Chen, Jimin; Du, Chuanjun

    2015-01-01

    A certain proportion of patients with initial Percutaneous nephrolithotripsy (PCNL) management require ancillary procedures to increase the stone-free rate. In this study, we aim to analyze the efficacy and safety of flexible ureteroscopy combined with holmium laser lithotripsy (F-UL) for treatment of residual calculi after PCNL by comparison with extracorporeal shockwave lithotripsy (SWL). Total of 96 patients with residual renal calculi (4 mm to 20 mm) after PCNL was enrolled from May 2010 to March 2013. They were randomly divided into two groups: US Group: patients were treated with F-UL; SWL Group: patients were treated with SWL. Follow-up was made one month and three months after treatment. The mean residual stone size after PCNL was 12.4 ± 4.3 mm in US group compared with 11.9 ± 4.5 in SWL group. The stone-free rate was 84.7% one month after surgical procedure in US group, this rate increased to 91.3% in the third months, while the stone-free rate in SWL group is 64.6% one month after treatment and 72.9% in the third month. For residual stone in lower calyx, the stone-free rate three month after treatment was 90.4% in US group compared to 65.2% in SWL group (P < 0.05). The overall complication rate was low in both groups, no severe complication was found. Both F-UL and SWL are safe and effective methods for residual calculi after PCNL, without severe complications. F-UL provided significantly higher stone-free rate compared with SWL, especially for low-pole calculi. PMID:26064375

  11. Cost-effectiveness of extracorporeal shock wave lithotripsy in a poor resource setting: The Okada, Nigeria experience

    PubMed Central

    Eze, Kenneth C.; Irekpita, E.; Salami, T. A.

    2016-01-01

    Background: The first extracorporeal shock wave lithotripsy (ESWL) used in Nigeria was at Igbinedion Hospital and Medical Research Centre (IHMRC), Okada in 1992 and it functioned for 6 consecutive years. The objectives of this study were to analyze the cost-effectiveness of the procedure and highlight the associated factors that led to its failure. Methods: A retrospective study of medical records and publications associated with the use of ESWL at IHMRC, Okada, for the period of 1992 to 1998. The study was conducted between January 2003 and November 2008. Unclassified authentic information relating to the use of ESWL and treatment of upper urinary tract stones was obtained from the IHMRC Okada and some government hospitals on hospital bills. Relevant documents in public domains related to the national and international wages and emoluments of medical workers and socioeconomic development of Nigeria within the time the ESWL functioned were studied. Result: A total of 32 patients were treated with 51 treatment sessions which is an average of nine patients per year and an average of two treatment sessions per patient were involved. The reasons for the low patronage were the extremely low stone formation rate of Nigerians, poverty, and out-of-pocket payment system. In addition, each treatment session of ESWL at Okada cost an average of $681.8 compared to $227.3 for open nephrolithotomy in a nearby high profile teaching hospital. The IHMRC, Okada, paid an average annual salary of ₦180,000 ($8,181.8) for each medical consultant compared to ₦120,000 ($5,454.5) paid by federal teaching hospitals in Nigeria within the period. Expatriate consultant doctors from Europe and USA who initially manned the lithotriptor at IHMRC, Okada, were paid much higher salaries. Average annual income of $5,909 for each of the 6 years amounting to a total of $34,771.7 for the six years was realized which could not maintain staff salaries in the hospital leading to staff emigration, decline of the hospital services, and eventual closure of the ESWL procedure center in the hospital in 1998. Conclusion: ESWL at Okada was not cost-effective both to patients and the hospital management. Despite these, ESWL is desirable in poor-resource countries because of its noninvasiveness, low morbidity, and usability in patients who are unfit for open surgery. Purchasing high technological medical equipment as commodities by sub-Saharan Africans without considering the prevalence of diseases they are meant to cater for, their maintenance for steady function during useful lifespan, their cost-effectiveness and how to recoup the money spent on investments depletes the scarce foreign exchange reserve of the home countries and is eventually counterproductive as exemplified by this case.

  12. Shock Wave Lithotripsy

    MedlinePlus

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  13. Focused Ultrasound and Lithotripsy.

    PubMed

    Ikeda, Teiichiro; Yoshizawa, Shin; Koizumi, Norihiro; Mitsuishi, Mamoru; Matsumoto, Yoichiro

    2016-01-01

    Shock wave lithotripsy has generally been a first choice for kidney stone removal. The shock wave lithotripter uses an order of microsecond pulse durations and up to a 100 MPa pressure spike triggered at approximately 0.5-2 Hz to fragment kidney stones through mechanical mechanisms. One important mechanism is cavitation. We proposed an alternative type of lithotripsy method that maximizes cavitation activity to disintegrate kidney stones using high-intensity focused ultrasound (HIFU). Here we outline the method according to the previously published literature (Matsumoto et al., Dynamics of bubble cloud in focused ultrasound. Proceedings of the second international symposium on therapeutic ultrasound, pp 290-299, 2002; Ikeda et al., Ultrasound Med Biol 32:1383-1397, 2006; Yoshizawa et al., Med Biol Eng Comput 47:851-860, 2009; Koizumi et al., A control framework for the non-invasive ultrasound the ragnostic system. Proceedings of 2009 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), pp 4511-4516, 2009; Koizumi et al., IEEE Trans Robot 25:522-538, 2009). Cavitation activity is highly unpredictable; thus, a precise control system is needed. The proposed method comprises three steps of control in kidney stone treatment. The first step is control of localized high pressure fluctuation on the stone. The second step is monitoring of cavitation activity and giving feedback on the optimized ultrasound conditions. The third step is stone tracking and precise ultrasound focusing on the stone. For the high pressure control we designed a two-frequency wave (cavitation control (C-C) waveform); a high frequency ultrasound pulse (1-4 MHz) to create a cavitation cloud, and a low frequency trailing pulse (0.5 MHz) following the high frequency pulse to force the cloud into collapse. High speed photography showed cavitation collapse on a kidney stone and shock wave emission from the cloud. We also conducted in-vitro erosion tests of model and natural kidney stones. For the model stones, the erosion rate of the C-C waveform showed a distinct advantage with the combined high and low frequency waves over either wave alone. For optimization of the high frequency ultrasound intensity, we investigated the relationship between subharmonic emission from cavitation bubbles and stone erosion volume. For stone tracking we have also developed a non-invasive ultrasound theragnostic system (NIUTS) that compensates for kidney motion. Natural stones were eroded and most of the resulting fragments were less than 1 mm in diameter. The small fragments were small enough to pass through the urethra. The results demonstrate that, with the precise control of cavitation activity, focused ultrasound has the potential to be used to develop a less invasive and more controllable lithotripsy system. PMID:26486335

  14. A new semiconductor lithotripsy sensor.

    PubMed

    Singh, V R

    2004-01-01

    Calibration of lithotripters is important for proper therapeutic treatment of the patients suffering with the presence of the stones in the kidney. Hence, a new semiconductor lithotripsy sensor is developed here to study the optimum performance of the kidney stone disintegrators. The present lithotripsy sensor has four-arm Wheatstone bridge sensor chip having associated electronics of signal conditioning, and amplifier etc. on the chip itself, and is fabricated, by using conventional bipolar IC process, in combination with bulk micromachining process. The starting material used is 5 ohm-cm p-type (100) silicon. The chip size is 3 mm square and the size of anisotropically etched diaphragm is 1.0mmx1.5 mmx20 micron (thickness). The pressure sensitivity is found to be 10 V/mm Hg pressure, with nonlinearity of 0.20% full scale output and thermal stability less than +1.5% over a temperature range of -50 degrees C to 300 degrees C. The smart semiconductor lithotripsy sensor, due to better sensitivity and resolution, is found useful in monitoring of the acoustic intensity level and pressure amplitude (in MPa range) of the shock waves generated by the ESWL. The calibration of the lithotripters is discussed here in detail. PMID:17270770

  15. Acoustic cavitation bubbles in the kidney induced by focused shock waves in extracorporeal shock wave lithotripsy (ESWL)

    NASA Astrophysics Data System (ADS)

    Kuwahara, M.; Ioritani, N.; Kambe, K.; Taguchi, K.; Saito, T.; Igarashi, M.; Shirai, S.; Orikasa, S.; Takayama, K.

    1990-07-01

    On an ultrasonic imaging system a hyperechoic region was observed in a focal area of fucused shock waves in the dog kidney. This study was performed to learn whether cavitation bubbles are responsible for this hyperechoic region. The ultrasonic images in water of varying temperatures were not markedly different. In the flowing stream of distilled water, the stream was demonstrated as a hyperechoic region only with a mixture of air bubbles. Streams of 5%-50% glucose solutions were also demonstrated as a hyperechoic region. However, such concentration changes in living tissue, as well as thermal changes, are hardly thought to be induced. The holographic interferometry showed that the cavitation bubbles remained for more than 500 msec. in the focal area in water. This finding indicate that the bubble can remain for longer period than previously supposed. These results support the contentions that cavitation bubbles are responsible for the hyperechoic region in the kidney in situ.

  16. Is an excretory urogram mandatory in patients with small to medium-sized renal and ureteric stones treated by extra corporeal shock wave lithotripsy?

    PubMed Central

    Ather, M Hammad; Faruqui, Nuzhat; Akhtar, Sobia; Sulaiman, M Nasir

    2004-01-01

    Background An intravenous urogram (IVU) has traditionally been considered mandatory before treating renal and ureteric stones by extracorporeal shock wave lithotripsy (ESWL). This study was designed to see whether there is a difference in complications and the need for ancillary procedures in patients managed by ESWL for renal and ureteric calculi, according to preoperative imaging technique. Methods This retrospective study compared 133 patients undergoing ESWL from January 2001 to July 2002. Patients were divided into three groups according to the preoperative imaging technique used: i) IVU; ii) non-contrast enhanced helical computed tomography (UHCT); and iii) ultrasound (US) + X-ray kidney, ureter and bladder (KUB). The groups were matched in terms of age and gender, as well as location, side and size of stones. Results There was no statistically significantly difference for number of ESWL sessions, number of shock waves and use of ancillary procedures between the three groups. The stone-free rate was 98% for the IVU and UHCT groups, and 97% for the US + X-ray KUB group. Conclusions The complication rate and need for ancillary procedures was comparable across the three groups. Patients imaged by UHCT or US + X-ray KUB prior to ESWL for uncomplicated renal and ureteric stones do not require IVU. PMID:15115545

  17. Is quantitative diffusion-weighted MRI a valuable technique for the detection of changes in kidneys after extracorporeal shock wave lithotripsy?

    PubMed Central

    Hocaoglu, Elif; Inci, Ercan; Aydin, Sibel; Cesme, Dilek Hacer; Kalfazade, Nadir

    2015-01-01

    Objective The aim of this study was to evaluate the capability and the reliability of diffusion-weighted imaging (DWI) in the changes of kidneys occurring after extracorporeal shock wave lithotripsy (ESWL) treatment for renal stones. Materials and Methods A total of 32 patients who underwent ESWL treatment for renal stone disease between June and December 2011 were enrolled in this prospective study. Color Doppler ultrasonography (CDUS) and DWI were performed before and within 24 hours after ESWL. DWI was obtained with b factors of 0, 500 and 1000 s/mm2 at 1.5 T MRI. Each of Resistive index (RI) and ADC values were calculated from the three regions of renal upper, middle and lower zones for both of the affected and contralateral kidneys. Paired sample t test was used for statistical analyses. Results After ESWL, the treated kidneys had statistically significant lower ADC values in all different regions compared with previous renal images. The best discriminative parameter was signal intensity with a b value of 1000 s/mm2. The changes of DWI after ESWL were noteworthy in the middle of the treated kidney (p<0.01). There were no significant difference between RI values in all regions of treated and contralateral kidneys before and after treatment with ESWL (p>0.05). Conclusion DWI is a valuable technique enables the detection of changes in DWI after ESWL treatment that may provide useful information in prediction of renal damage by shock waves, even CDUS is normal. PMID:25928520

  18. Extracorporeal shock waves lithotripsy versus retrograde ureteroscopy: is radiation exposure a criterion when we choose which modern treatment to apply for ureteric stones?

    PubMed Central

    Pricop, Catalin; Maier, Adrian; Negru, Dragos; Malau, Ovidiu; Orsolya, Martha; Radavoi, Daniel; Serban, Dragomir R.

    2014-01-01

    The aim of this study is to compare two major urological procedures in terms of patient exposure to radiation. We evaluated 175 patients, that were subjected to retrograde ureteroscopy (URS) and extracorporeal shock waves lithotripsy (ESWL) for lumbar or pelvic ureteral lithiasis, at two urological departments. The C-arm Siemens (produced in 2010 by Siemens AG, Germany) was used for ureteroscopy. The radiological devices of the lithotripters used in this study in the two clinical centers had similar characteristics. We evaluated patient exposure to ionizing radiation by using a relevant parameter, the air kerma-area product (PKA; all values in cGy cm2), calculated from the radiation dose values recorded by the fluoroscopy device. PKA depends on technical parameters that change due to anatomical characteristics of each case examined, such as body mass index (BMI), waist circumference, and stone location. For the patients subjected to ESWL for lumbar ureteral lithiasis the mean of PKA(cGy cm2) was 509 (SD=180), while for those treated for pelvic ureteral lithiasis the mean of PKA was 342 (SD=201). In the URS group for lumbar ureteral lithiasis, the mean of PKA (cGy cm2) was 892 (SD=436), while for patients with pelvic ureteral lithiasis, the mean of PKA was 601 (SD=429). The patients treated by URS had higher exposure to ionizing radiation dose than patients treated by ESWL. The risk factors of higher radiation doses were obesity, exposure time, and localization of the stones. PMID:25428680

  19. Pain control using pethidine in combination with diazepam compared to diclofenac in combination with hyoscine-n-butyl bromide: in patients undergoing extracorporeal shock wave lithotripsy

    PubMed Central

    Cecen, Kursat; Karadag, Mert Ali; Uslu, Mehmet; Arslan, Omer Erkam

    2015-01-01

    Introduction Extracorporeal Shock Wave Lithotripsy (ESWL) remains the preferred least invasive treatment for urinary tract stones. The main purpose of this study was to compare two treatment modalities for pain control during the ESWL procedure. Material and methods From 2013 to 2014, 220 patients received ESWL for kidney stones. Before the procedure, the weight and height were measured to determine the body mass index (BMI); in addition, oxygen saturation and the pulse of the patients, as well as pain level were determined. The pain control provided included two different methods: diclofenac sodium plus hyoscine-N-butyl bromide in the first group and pethidine plus diazepam in the second group. The pain level of the patients was determined using two different scales: the Wong-Baker and the Visual Analogue scales (VAS). At the end of three sessions, all patients were evaluated for the stone fragmentation rate by plain abdominal X-ray, and the findings were recorded and analyzed. Results A total of 220 patients were enrolled in this study. There were 91 patients in the first group (diclofenac sodium + hyoscine-N-butyl bromide) (male/female: 63/28) and 129 (male/female: 83/46) patients in the second group (pethidine HCL +diazepam). The mean age with SD according to each group was 42.03 (±16.43) and 42.56 (±14.23), respectively (p = 0.8). With regard to pain scores (using the Wong-Baker and VAS scales), the responses were significantly lower in the second group (p <0.001). Conclusions Pethidine in combination with diazepam was superior to diclofenac and Hyoscine-N-butyl bromide for pain in patients undergoing ESWL. PMID:26251744

  20. Extracorporeal shock wave lithotripsy versus retrograde intrarenal surgery for treatment for renal stones 1-2 cm: a meta-analysis.

    PubMed

    Zheng, Changjian; Yang, Hongmei; Luo, Jun; Xiong, Bo; Wang, Hongzhi; Jiang, Qing

    2015-11-01

    This study is to evaluate the efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) versus retrograde intrarenal surgery (RIRS) for the treatment for renal calculi 1-2 cm. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the Chinese Biomedical Literature Database were researched and hand-searched for relevant congress abstracts and journals about RIRS and ESWL for the treatment for 1- to 2-cm renal stones. The retrieval time ended in September 2014. The related trials met the inclusion criteria were included in the meta-analysis. Two reviewers independently assessed the quality of all included studies, and meta-analysis was performed with RevMan 5.2. Seven literatures were retrieved, including 983 patients. The meta-analysis results showed that, compared to RIRS group, the patients in ESWL group had the following features:(1) the stone-free rate [relative risk (RR) 0.86; 95% confidence interval (CI) 0.77-0.95, P = 0.005] was significantly different between two groups; (2) The retreatment rate of RIRS group was lower (RR 8.12; 95% CI 4.77-13.83, P < 0.00); (3) The complications were not significantly different between two groups (Grade I RR 1.06; 95% CI 0.67-1.69, P = 0.80; Grade II RR 0.75; 95% CI 0.29-1.91, P = 0.54; Grade III RR 0.86; 95% CI 0.26-2.86, P = 0.80). Compared to ESWL, our results showed that RIRS provided significantly higher stone-free rate and lower retreatment rate and without increase in the incidence of complications. However, further randomized trials are needed to confirm these findings. PMID:26211003

  1. Optimal Skin-to-Stone Distance Is a Positive Predictor for Successful Outcomes in Upper Ureter Calculi following Extracorporeal Shock Wave Lithotripsy: A Bayesian Model Averaging Approach

    PubMed Central

    Cho, Kang Su; Jung, Hae Do; Ham, Won Sik; Chung, Doo Yong; Kang, Yong Jin; Jang, Won Sik; Kwon, Jong Kyou; Choi, Young Deuk; Lee, Joo Yong

    2015-01-01

    Objectives To investigate whether skin-to-stone distance (SSD), which remains controversial in patients with ureter stones, can be a predicting factor for one session success following extracorporeal shock wave lithotripsy (ESWL) in patients with upper ureter stones. Patients and Methods We retrospectively reviewed the medical records of 1,519 patients who underwent their first ESWL between January 2005 and December 2013. Among these patients, 492 had upper ureter stones that measured 4–20 mm and were eligible for our analyses. Maximal stone length, mean stone density (HU), and SSD were determined on pretreatment non-contrast computed tomography (NCCT). For subgroup analyses, patients were divided into four groups. Group 1 consisted of patients with SSD<25th percentile, group 2 consisted of patients with SSD in the 25th to 50th percentile, group 3 patients had SSD in the 50th to 75th percentile, and group 4 patients had SSD≥75th percentile. Results In analyses of group 2 patients versus others, there were no statistical differences in mean age, stone length and density. However, the one session success rate in group 2 was higher than other groups (77.9% vs. 67.0%; P = 0.032). The multivariate logistic regression model revealed that shorter stone length, lower stone density, and the group 2 SSD were positive predictors for successful outcomes in ESWL. Using the Bayesian model-averaging approach, longer stone length, lower stone density, and group 2 SSD can be also positive predictors for successful outcomes following ESWL. Conclusions Our data indicate that a group 2 SSD of approximately 10 cm is a positive predictor for success following ESWL. PMID:26659086

  2. Intracorporeal laser lithotripsy

    PubMed Central

    Papatsoris, Athanasios G.; Skolarikos, Andreas; Buchholz, Noor

    2012-01-01

    Objectives To review the current literature on intracorporeal laser lithotripsy. Methods We searched PubMed for relevant reports up to January 2012, using the keywords ‘laser’, ‘lithotripsy’ and ‘intracorporeal’. Results We studied 125 relevant reports of studies with various levels of evidence. Efficient lithotripsy depends on the laser variables (wavelength, pulse duration and pulse energy) and the physical properties of the stones (optical, mechanical and chemical). The most efficient laser for stones in all locations and of all mineral compositions is the holmium yttrium–aluminium–garnet laser (Ho:YAG). The frequency-doubled double-pulse Nd:YAG laser functions through the generation of a plasma bubble. New laser systems, such as the erbium:YAG and the thulium laser, are under evaluation. Laser protection systems have also been developed for the novel digital flexible ureteroscopes. Although complications are rare, a high relevant clinical suspicion is necessary. Conclusions Laser lithotripsy technology is continuously developing, while the Ho:YAG laser remains the reference standard for intracorporeal lithotripsy. PMID:26558041

  3. Comparative Study of Lithotripsy and PCNL for 11-15 mm Lower Caliceal Calculi In Community Health Hospital

    PubMed Central

    Gadekar, Jayant; Shinde, Babaji B.; Tatte, Julie Anand

    2014-01-01

    Background and Purpose: Percutaneous Nephrolithotomy (PCNL) is not a popular procedure in smaller sized calculi due to its invasive nature, complications and need for anesthesia. Small sized lower caliceal calculi are generally treated by ESWL but have significantly less clearance rate in spite of several sittings. Here we want to study the efficacy and safe of both procedures in 11 to 15 mm lower caliceal calculi. Materials and Methods: We present comparative study of lithotripsy and PCNL in 11-15 mm lower caliceal calculi in our hospital. Total 156 patients were studied 78 underwent lithotripsy and 78 underwent PCNL. We compared results in the form of clearance rate, the number of settings needed, hospital stay, need for anesthesia, blood transfusion rate, chest complication, the incidence of sepsis, the need for another procedure, need for stenting in either group. Results: We found a 67.95% clearance rate in SWL group and 97.43% clearance rate in PCNL group. Hospital stay was minimum in SWL group and was 46 hours in PCNL group. The procedure time was 42 minutes in PCNL and it was 114 mins in SWL (considering all settings). The rest of the complications like chest complication, sepsis and bleeding were negligible due to the small size of calculi. Conclusion: In a small sized LPC calculi, PCNL is gaining increased popularity due to lower complication and high safety and complete clearance rate. It is wide accepted by society as the patient is totally stone free at the end of the procedure. SWL is less invasive but less effective and has given significant discomfort to patients. PMID:25121001

  4. Extracorporeal shock wave lithotripsy of gall stones: an in vitro comparison between an electrohydraulic and a piezoceramic device.

    PubMed Central

    Schachler, R; Bird, N C; Sauerbruch, T; Frost, E A; Sackmann, M; Paumgartner, G; Johnson, A G

    1991-01-01

    A comparative study of the effectiveness of two types of lithotripter in fragmenting gall bladder stones is reported. The machines used were a Piezolith 2300, which generates shock waves by the piezoceramic principle, and a Dornier MPL 9000, which produces the shock waves by underwater spark discharge. With each machine, corresponding stones of 45 pairs of weight and volume matched calculi (median volume 0.5 cm3, median diameter 10.5 mm) obtained at cholecystectomy were treated. All stones were successfully disintegrated (fragments smaller than 2 mm) with up to 5400 (median 628) shocks with the Piezolith and 3450 (median 428) shocks with the MPL 9000 lithotripters. With the Piezolith, operating at the highest power setting, a 1.65 fold median higher number of shocks was required for stone fragmentation than with the MPL 9000 at a medium power setting. Stone volume seemed to be the only determinant which affected ease of fragmentation; composition and density of the stones as assessed by computed tomography did not seem to be governing factors. Images Figure 5 PMID:2013428

  5. Improving the lens design and performance of a contemporary electromagnetic shock wave lithotripter

    PubMed Central

    Neisius, Andreas; Smith, Nathan B.; Sankin, Georgy; Kuntz, Nicholas John; Madden, John Francis; Fovargue, Daniel E.; Mitran, Sorin; Lipkin, Michael Eric; Simmons, Walter Neal; Preminger, Glenn M.; Zhong, Pei

    2014-01-01

    The efficiency of shock wave lithotripsy (SWL), a noninvasive first-line therapy for millions of nephrolithiasis patients, has not improved substantially in the past two decades, especially in regard to stone clearance. Here, we report a new acoustic lens design for a contemporary electromagnetic (EM) shock wave lithotripter, based on recently acquired knowledge of the key lithotripter field characteristics that correlate with efficient and safe SWL. The new lens design addresses concomitantly three fundamental drawbacks in EM lithotripters, namely, narrow focal width, nonidealized pulse profile, and significant misalignment in acoustic focus and cavitation activities with the target stone at high output settings. Key design features and performance of the new lens were evaluated using model calculations and experimental measurements against the original lens under comparable acoustic pulse energy (E+) of 40 mJ. The ?6-dB focal width of the new lens was enhanced from 7.4 to 11 mm at this energy level, and peak pressure (41 MPa) and maximum cavitation activity were both realigned to be within 5 mm of the lithotripter focus. Stone comminution produced by the new lens was either statistically improved or similar to that of the original lens under various in vitro test conditions and was significantly improved in vivo in a swine model (89% vs. 54%, P = 0.01), and tissue injury was minimal using a clinical treatment protocol. The general principle and associated techniques described in this work can be applied to design improvement of all EM lithotripters. PMID:24639497

  6. Music does not reduce alfentanil requirement during patient-controlled analgesia (PCA) use in extracorporeal shock wave lithotripsy for renal stones.

    PubMed

    Cepeda, M S; Diaz, J E; Hernandez, V; Daza, E; Carr, D B

    1998-12-01

    To evaluate the impact of music on opioid requirements and pain levels during renal lithotripsy using alfentanil patient-controlled analgesia (PCA), we conducted a prospective, blinded, randomized controlled trial. Patients undergoing lithotripsy were instructed in PCA use and asked to rate their anxiety and select their preferred type of music. They were then premedicated with morphine and ketorolac and randomly allocated into two groups. Group 1 (n = 97) had music started 10 min before the procedure and maintained until 10 min after its conclusion. Group 2 (n = 96) had music begun at the conclusion of lithotripsy and continued for 10 min. Pain intensity, alfentanil requirement, side effects, quality of analgesia, patient satisfaction, and acceptance of the technique were evaluated. Demographics, alfentanil requirement, pain levels, side effects, quality of analgesia, and patient satisfaction were similar in both groups. The addition of music did not provide any benefit. This result raises the possibility that some nonpharmacologic therapies have minimal impact in settings where the painful stimulus is moderate to severe and adequate pharmacotherapy is available. PMID:9879163

  7. A Possible Cumulative Shear Mechanism For Tissue Damage Initiation In SWL

    NASA Astrophysics Data System (ADS)

    Freund, Jonathan B.

    2007-04-01

    In shock-wave lithotripsy, inertial cavitation is observed in kidney tissue after hundreds of shocks are delivered, which seems to correspond with the onset of wide-spread injury. However, it is unclear what initiates the process. It is possible, and has been suggested before, that hemorrhage is a prelude to cavitation damage. We investigate the possibility that the net shear of multiple shocks can accumulate to cause this initial hemorrhage. A mathematical model is used to show that the larger interstitial volume fraction in the medulla toward the papilla tip would make it particularly sensitive there to this mechanism. This is consistent with observations.

  8. Thulium Fiber Laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard Leious, Jr.

    The Thulium Fiber Laser (TFL) has been studied as a potential alternative to the conventional Holmium:YAG laser (Ho:YAG) for the treatment of kidney stones. The TFL is more ideally suited for laser lithotripsy because of the higher absorption coefficient of the emitted wavelength in water, the superior Gaussian profile of the laser beam, and the ability to operate at arbitrary temporal pulse profiles. The higher absorption of the TFL by water helps translate into higher ablation of urinary stones using less energy. The Gaussian spatial beam profile allows the TFL to couple into fibers much smaller than those currently being used for Ho:YAG lithotripsy. Lastly, the ability of arbitrary pulse operation by the TFL allows energy to be delivered to the stone efficiently so as to avoid negative effects (such as burning or bouncing of the stone) while maximizing ablation. Along with these improvements, the unique properties of the TFL have led to more novel techniques that have currently not been used in the clinic, such as the ability to control the movement of stones based on the manner in which the laser energy is delivered. Lastly, the TFL has led to the development of novel fibers, such as the tapered fiber and removable tip fiber, to be used for lithotripsy which can lead to safer and less expensive treatment of urinary stones. Overall, the TFL has been demonstrated as a viable alternative to the conventional Ho:YAG laser and has the potential to advance methods and tools for treatment of kidney stones.

  9. Kidney Stone Treatment with Lithotripsy

    MedlinePlus Videos and Cool Tools

    Kidney Stone Treatment with Lithotripsy Broward Health Medical Center Fort Lauderdale, FL November 11, 2011 I'm ... got at least three stones in his left kidney. He's been having pain and blood in his ...

  10. Femtosecond laser lithotripsy: feasibility and ablation mechanism

    NASA Astrophysics Data System (ADS)

    Qiu, Jinze; Teichman, Joel M. H.; Wang, Tianyi; Neev, Joseph; Glickman, Randolph D.; Chan, Kin Foong; Milner, Thomas E.

    2010-03-01

    Light emitted from a femtosecond laser is capable of plasma-induced ablation of various materials. We tested the feasibility of utilizing femtosecond-pulsed laser radiation (λ=800 nm, 140 fs, 0.9 mJ/pulse) for ablation of urinary calculi. Ablation craters were observed in human calculi of greater than 90% calcium oxalate monohydrate (COM), cystine (CYST), or magnesium ammonium phosphate hexahydrate (MAPH). Largest crater volumes were achieved on CYST stones, among the most difficult stones to fragment using Holmium:YAG (Ho:YAG) lithotripsy. Diameter of debris was characterized using optical microscopy and found to be less than 20 μm, substantially smaller than that produced by long-pulsed Ho:YAG ablation. Stone retropulsion, monitored by a high-speed camera system with a spatial resolution of 15 μm, was negligible for stones with mass as small as 0.06 g. Peak shock wave pressures were less than 2 bars, measured by a polyvinylidene fluoride (PVDF) needle hydrophone. Ablation dynamics were visualized and characterized with pump-probe imaging and fast flash photography and correlated to shock wave pressures. Because femtosecond-pulsed laser ablates urinary calculi of soft and hard compositions, with micron-sized debris, negligible stone retropulsion, and small shock wave pressures, we conclude that the approach is a promising candidate technique for lithotripsy.

  11. Laser lithotripsy: a review of 20 years of research and clinical applications.

    PubMed

    Dretler, S P

    1988-01-01

    Four new technologies have transformed the treatment of urinary calculi: electrohydraulic lithotripsy, ultrasonic lithotripsy, extracorporeal shock wave lithotripsy, and laser lithotripsy. Initial attempts to ablate urinary calculi by continuous wave CO2, ruby, and Nd-YAG lasers failed because of excess thermal injury and inability to pass the laser energy via a flexible fiber. Basic laboratory studies then demonstrated that short pulsed laser energy absorbed by the calculus resulted in fragmentation. The parameters that produced optimal urinary calculus fragmentation were found using the flashlamp pumped tunable dye laser, with the following parameters: wavelength: 504 nm; pulse duration: 1 microsec; fiber: 250 micro silica-coated quartz; repetition: 5-20 Hz. Use of pulsed dye laser caused no tissue damage. The mechanism of fragmentation is light absorption, plasma development, and repetitive acoustic shock wave action with resultant fragmentation. The techniques for application of laser to calculi have been successful, and new, miniature instruments have been developed. Laser lithotripsy is a successful method for fragmenting ureteral calculi. The small caliber of the laser fiber makes this method useful for treating calculi in narrow, tortuous ureters; impacted calculi; distal calculi in ureters that cannot be dilated, via the percutaneous route for stones in calyces or impacted in the upper ureter. Investigations are continuing to optimize fragmentation of harder calculi and to use laser fragmentation within the kidney. Laser lithotripsy may also be used to fragment biliary calculi. PMID:2902498

  12. Holmium laser lithotripsy of bladder calculi

    NASA Astrophysics Data System (ADS)

    Beaghler, Marc A.; Poon, Michael W.

    1998-07-01

    Although the overall incidence of bladder calculi has been decreasing, it is still a significant disease affecting adults and children. Prior treatment options have included open cystolitholapaxy, blind lithotripsy, extracorporeal shock wave lithotripsy, and visual lithotripsy with ultrasonic or electrohydraulic probes. The holmium laser has been found to be extremely effective in the treatment of upper tract calculi. This technology has also been applied to the treatment of bladder calculi. We report our experience with the holmium laser in the treatment of bladder calculi. Twenty- five patients over a year and a half had their bladder calculi treated with the Holmium laser. This study was retrospective in nature. Patient demographics, stone burden, and intraoperative and post-operative complications were noted. The mean stone burden was 31 mm with a range of 10 to 60 mm. Preoperative diagnosis was made with either an ultrasound, plain film of the abdomen or intravenous pyelogram. Cystoscopy was then performed to confirm the presence and determine the size of the stone. The patients were then taken to the operating room and given a regional or general anesthetic. A rigid cystoscope was placed into the bladder and the bladder stone was then vaporized using the holmium laser. Remaining fragments were washed out. Adjunctive procedures were performed on 10 patients. These included transurethral resection of the prostate, transurethral incision of the prostate, optic internal urethrotomy, and incision of ureteroceles. No major complications occurred and all patients were rendered stone free. We conclude that the Holmium laser is an effective and safe modality for the treatment of bladder calculi. It was able to vaporize all bladder calculi and provides a single modality of treating other associated genitourinary pathology.

  13. Shock-Induced Bubble Collapse in a Vessel: Implications for Vascular Injury in Shockwave Lithotripsy

    NASA Astrophysics Data System (ADS)

    Coralic, Vedran; Colonius, Tim

    2013-11-01

    We numerically investigate the shock-induced collapse (SIC) of a preexisting bubble in a blood vessel and evaluate the potential of such an event to contribute to onset of vascular injury in shockwave lithotripsy (SWL). Previously, we utilized a 3D, high-order accurate, shock- and interface-capturing, multicomponent flow algorithm to carry out a large-scale parametric study of this problem [V. Coralic and T. Colonius, Eur. J. Mech. B-Fluid 40, 64-74 (2013)]. The results indicated that the influence of the blood vessel on the bubble dynamics was negligible and confirmed with experiments that the vessel would freely deform under the forcing imparted by the collapse. As a result, in this study, we perform simulations of the SIC of a preexisting bubble in a free field and couple them to a freely deforming Lagrangian mesh so to characterize the deformations in the fluid surrounding the bubble, which, as our previous results suggest, may be interpreted as the vessel and surrounding tissue. We report the fully 3D and time-dependent Green-Lagrange strains and compare them to the ultimate strains obtained in uniaxial compression/tension tests in tissue. Our findings suggest that the SIC of preexisting bubbles in blood vessels is a viable mechanism by which injury may be initiated in SWL. This research was supported by NIH grant no. 2PO1DK043881 and utilized XSEDE, which is supported by NSF grant no. OCI-1053575.

  14. Patient and personnel exposure during extracorporeal lithotripsy

    SciTech Connect

    Glaze, S.; LeBlanc, A.D.; Bushong, S.C.; Griffith, D.P.

    1987-12-01

    Extracorporeal shock wave lithotripsy (ESWL) has provided a nonsurgical approach to treatment of renal stones. The Dornier lithotripter uses dual image intensified x-ray systems to center the stone before treatment. Three imaging modes are offered: a fluoroscopic mode and two video spot filming modes. The average entrance exposure to the stone side of the typical patient at our facility is 2.6 X 10(-3) C kg-1 (10 R) (range: 0.5-7.7 X 10(-3) C kg-1 (2-30 R)) which is comparable and often much less than that reported for percutaneous lithotripsy. Recommendations are made for minimizing patient exposure. Scattered radiation levels in the lithotripter room are presented. We have determined that Pb protective apparel is not required during this procedure provided x-ray operation is temporarily halted should personnel be required to lean directly over the tub to attend to the patient. If the walls of the ESWL room are greater than 1.83 m (6 feet) from the tub, shielding in addition to conventional construction is not required.

  15. Optically triggered solid state driver for shock wave therapy

    NASA Astrophysics Data System (ADS)

    Duryea, Alexander P.; Roberts, William W.; Cain, Charles A.; Hall, Timothy L.

    2012-10-01

    Shock wave lithotripsy (SWL) represents one of several first-line therapies for the treatment of stones located in the kidneys and ureters. Additional applications for shock wave therapy are also under exploration, including non-urinary calculi, orthopedics, and neovascularization. Except for the elimination of a large water bath in which the treatment is performed, current procedures remain largely unchanged, with one of the original commercial devices (the Dornier HM3) still considered a gold standard for comparison. To accelerate research in this area, Coleman, et al. published an experimental electrohydraulic shock wave generator capable of simulating the acoustic field generated by the HM3. We propose a further update of this system, replacing the triggered spark gap with an optically triggered solid state switch. The new system has better reliability, a wider operating range, and reduced timing jitter allowing synchronization with additional acoustic sources under exploration for improving efficacy and reducing injury. Originally designed for exciting electrohydraulic spark electrodes, the system can also be adapted for driving piezoelectric and electromagnetic sources.

  16. Bubble Dynamics in Laser Lithotripsy

    NASA Astrophysics Data System (ADS)

    Mohammadzadeh, Milad; Martinez Mercado, Julian; Ohl, Claus-Dieter

    2015-12-01

    Laser lithotripsy is a medical procedure for fragmentation of urinary stones with a fiber guided laser pulse of several hundred microseconds long. Using high-speed photography, we present an in-vitro study of bubble dynamics and stone motion induced by Ho:YAG laser lithotripsy. The experiments reveal that detectable stone motion starts only after the bubble collapse, which we relate with the collapse-induced liquid flow. Additionally, we model the bubble formation and dynamics using a set of 2D Rayleigh-Plesset equations with the measured laser pulse profile as an input. The aim is to reduce stone motion through modification of the temporal laser pulse profile, which affects the collapse scenario and consequently the remnant liquid motion.

  17. Flexible Ureterorenoscopy versus Extracorporeal Shock Wave Lithotripsy for the treatment of upper/middle calyx kidney stones of 10-20 mm: a retrospective analysis of 174 patients.

    PubMed

    Cecen, Kursat; Karadag, Mert Ali; Demir, Aslan; Bagcioglu, Murat; Kocaaslan, Ramazan; Sofikerim, Mustafa

    2014-01-01

    To compare the outcomes of flexible ureterorenoscopy (F-URS) with extracorporeal shock wave lithotripsy (ESWL) for the treatment of upper or mid calyx kidney stones of 10 to 20 mm. A total of 174 patients with radioopaque solitary upper or mid calyx stones who underwent ESWL or F-URS with holmium:YAG laser were enrolled in this study. Each group treated with ESWL and F-URS for upper or mid calyx kidney stones were retrospectively compared in terms of retreatment and stone free rates, and complications. 87% (n = 94) of patients who underwent ESWL therapy was stone free at the end of 3rd month. This rate was 92% (n = 61) for patients of F-URS group (p = 0.270 p > 0.05). Retreatment was required in 12.9% of patients (n = 14) who underwent ESWL and these patients were referred to F-URS procedure after 3rd month radiologic investigations. The retreatment rate of cases who were operated with F-URS was 7.5% (n = 5) (p = 0.270 p > 0.05). Ureteral perforation (Clavien grade 3B) was occured in 3 patients (4.5%) who underwent F-URS. Fever (Clavien grade 1) was noted in 7 and 5 patients from ESWL and F-URS group, respectively (6.4% vs 7.5%) (p = 0.78 p > 0.05). F-URS and ESWL have similar outcomes for the treatment of upper or mid calyx renal stones of 10-20 mm. ESWL has the superiority of minimal invasiveness and avoiding of general anethesia. F-URS should be kept as the second teratment alternative for patients with upper or mid caliceal stones of 10-20 mm and reserved for cases with failure in ESWL. PMID:25332859

  18. [Extracorporeal electromagnetic shock-wave lithotripsy. Initial results in the treatment of ureteral calculi in situ. A series of 50 consecutive cases].

    PubMed

    Conort, P; Ledenko, N; Léo, J P; Richard, F; Chatelain, C

    1990-01-01

    Electromagnetic shock waves are sufficiently powerful to break ureteral stones in situ under X-ray control. Fifty consecutive patients were treated for ureteral stones (20 lombar, 4 iliac, 26 pelvic); the average length was 7.5 mm; 48 times in one session, twice in two sessions. At 6 months, 98% of these patients were stone-free (with IVP control) and one patient was lost to follow-up. PMID:2360783

  19. A perspective on laser lithotripsy: the fragmentation processes.

    PubMed

    Chan, K F; Pfefer, T J; Teichman, J M; Welch, A J

    2001-04-01

    This paper describes in simple terms the physics of laser-calculus interactions and introduces a method with which physicians can understand or evaluate the application of any new laser technique for use in lithotripsy or other medical fields. Tissue optical properties and laser parameters govern the mechanism(s) of fragmentation of urinary or biliary calculi. Laser pulse energies for clinical lithotripsy range from Q0 = 20 mJ to 2 J for short-pulsed lasers to long-pulsed lasers, respectively. Lasers with short pulse durations (i.e., less than a few microseconds) fragment calculi by means of shockwaves following optical breakdown and plasma expansion of ionized water or calculus compositions or by cavitation collapse, thus manifesting a photoacoustical effect. Laser-tissue interactions involving dominant photomechanical or photoacoustical effects are usually stress confined. Long-pulsed lasers (i.e., >100 microsec), on the other hand, generate minimal acoustic waves, and calculi are fragmented by temperatures beyond the thresholds for vaporization of calculus constituents, melting, or chemical decomposition. PMID:11339391

  20. [Case of renal subcapsular hematoma caused by flexible transurethral lithotripsy].

    PubMed

    Watanabe, Ryuta; Inada, Kouji; Azuma, Kouji; Yamashita, Yokihiko; Oka, Akihiro

    2013-09-01

    A 39-year-old man with macroscopic hematuria was admitted to our hospital. A stone, 5 mm in diameter was detected in the right ureteropelvic junction after abdominal computed tomography and plain abdominal radiography. We performed flexible transurethral lithotripsy (f-TUL) and crushed the stone and extracted almost all stone fragments without any complications. However, almost immediately after the operation, the patient began to complain about pain in the right back. In the results of abdominal plain computed tomography right renal subcapsular hematoma was detected. Because active bleeding was not observed in the results of enhanced computed tomography, only conservative treatment was performed. The patient was discharged from the hospital on day 11 of hospitalization. One month after the operation, plain computed tomography was performed and diminished subcapsular hematoma was detected. Renal subcapsular hematoma is assumed to be a unique complication of extracorporeal shock wave lithotripsy. This is the first report of a case of renal subcapsular hematoma caused by f-TUL. The onset of renal subcapsular hematoma following f-TUL could have been caused either because the laser fiber thrust into the renal lithiasis unintentionally or because the internal pressure of the renal pelvis increased substantially during the operation. PMID:24113753

  1. Visualizing mechanical stress and liquid flow during laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Reinten, Ilja; Verdaasdonk, Rudolf; van der Veen, Albert; Klaessens, John

    2014-03-01

    The mechanism of action of the holmium laser lithotripsy is attributed to explosive expanding and imploding vapor bubbles in association with high-speed water jets creating high mechanical stress and cracking the stone surface. A good understanding of this mechanism will contribute to the improvement and the safety of clinical treatments. A new method has been developed to visualize the dynamics of mechanical effects and fluid flow induced by Holmium laser pulses around the fiber tip and the stone surface. The fiber tip was positioned near the surface of a stone on a slab of polyacrylamide gel submerged in water. The effects were captured with high speed imaging at 2000-10000 f/s. The dynamics of the pressure wave after the pulse could be visualized by observing the optical deformation of a fine line pattern in the background of the water container using digital subtraction software. This imaging technique provides a good understanding of the mechanical effects contributing to the effectiveness and safety of lithotripsy and can be used to study the optimal fiber shape and position towards the stone surface.

  2. [Clinical application of extracorporeal microexplosive lithotripsy].

    PubMed

    Honda, M; Maeda, S; Takasaki, E

    1989-03-01

    A total of 46 cases underwent 66 treatments with extracorporeal microexplosive lithotripsy (EML) for upper urinary tract calculi between March 10, 1987 and May 28, 1987. The efficacy of EML therapy was investigated in all cases over 3 months. The lithotripter of EML made by the Yachiyoda Co. Ltd (SZ-1) was adapted to a microexplosion (10 mg silver azide) as the source of energy for underwater shock wave generation. Fifteen cases (32.6%) had a history of previous open lithotomy of the same upper urinary tract as being treated by EML. Pre-treatments with ureteral catheters and ureteral stents were performed in 4 and 4 cases (8.7% and 8.7%), respectively. The microexplosions were conducted in syncronization with patient exhalation from 100 to 400 times during 1 session, depending upon the size of the stone. The patients felt pressure only on their back at the pulse of explosion and complained occasionally a dull pain, but this pain was mild and tolerable, and no patients required anesthesia. When stone disintegration was judged to be unsatisfactory, that is the stone remained unfragment or the size of the residual stone fragments was greater than 5 mm., an additional session was performed, usually 1 week after the previous session. On the X-ray film obtained three months after EML treatment, 26 cases (57%) were completely free from stone concerments, 17 cases (37%) had stone fragments of equal to or less than 5 mm and 3 cases (6%) had ones of greater than 5 mm. Treatment of EML alone was performed in 44 cases (96%), while 2 cases (4%) required transurethral stone manipulation following EML.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2735248

  3. Extracorporeal piezoelectric lithotripsy in unanesthetized children.

    PubMed

    Starr, N T; Middleton, R G

    1992-06-01

    Extracorporeal piezoelectric lithotripsy is an effective method for treating renal pelvic stones in children. Treatment with the Wolf lithotriptor is essentially painless and can be performed without anesthesia on an outpatient basis. Real-time ultrasound is used to localize stones. In a 1-year period at the University of Utah, extracorporeal piezoelectric lithotripsy was administered to eight children with nine renal units. Of the eight children, aged 5 to 17 1/2 years, only two required sedation and only one received retreatment. No stents were placed. At 1 month posttreatment, all children were stone-free, and no significant complications occurred. PMID:1594380

  4. Ureteroscopy and laser lithotripsy: technologic advancements.

    PubMed

    Alexander, B; Fishman, A I; Grasso, M

    2015-02-01

    Ureteroscopic lithotripsy has evolved since the first reported cases employing rigid rod-lens endoscopes and stiff ultrasonic lithotrites. Fiber optics facilitated rigid endoscope miniaturization and the development of a steerable, deflectable flexible ureteroscopes. Over 30 years of technical innovations culminating in digital imagers and powerful, precise laser lithotrites, complimented by progressive endoscopic techniques have produced efficient endoscopic therapies with minimal morbidity and commonly performed in an outpatient setting. PMID:25266163

  5. [Use of high frequency jet ventilation in extracorporeal shockwave lithotripsy].

    PubMed

    Schulte am Esch, J; Kochs, E; Meyer, W H

    1985-06-01

    High frequency jet ventilation (HFJV) was used in 68 patients which were treated with extracorporal shock wave lithotripsy (ESWL) because of stone diseases in the upper urinary tract. The question was whether HFJV in combination with a semiclosed conventional circle system offered a practicable and safe technique to minimize the oscillations which are proportional to the applied tidal volume and to the diaphragmatic movements. With IPPV the mean distance of the stone movement was 32 mm, whereas with the application of HFJV the stones oscillated around their resting position within limits of 2 to 3 mm (ventilation frequency: 200-300/min, driving pressure: 0.6-1.1 bar, tidal volume: 3-8 1/min). The effectiveness of HFJV was monitored by the end-tidal carbon dioxide tension (PeCO2) during intermittently conventional ventilation with "adequate" tidal volumes (TV 15 ml/kg bw). The correlation between PeCO2 and simultaneous measured PaCO2 was r = 0,91. The application of HFJV enhances the efficiency of ESWL. So the treatment of stones of the upper urinary tract can be varied by more subtle dosage of the incoming shock wave energy and by stabilisation of the stones in the underlying ellipsoid of the energy focus. PMID:3904519

  6. Extra corporeal shockwave lithotripsy resulting in skin burns--a report of two cases.

    PubMed

    Rao, Sandhya R; Ballesteros, Natalia; Short, Kerry L; Gathani, Krishna K; Ankem, Murali K

    2014-01-01

    Severe skin injury after extracorporeal shock wave lithotripsy (ESWL) is rare. We describe two patients who suffered full thickness skin burns following ESWL for renal calculi. One patient was treated conservatively and the other underwent debridement with skin grafting. We speculate that failure of the thermostatic mechanism of the lithotripter, leading to overheating of the water-filled cushion, resulted in this very rare adverse event. Proper preoperative patient counseling regarding the risk of serious burn injuries will help to avoid potential litigation. PMID:25615256

  7. Calcium Phosphate Composition Affects Ureteroscopic Laser Lithotripsy.

    PubMed

    Otsuki, Hideo; Yoshioka, Takashi; Shimizu, Toshihiro; Nakanishi, Yusuke; Fujio, Kei; Murao, Wataru; Uehara, Shinya; Kikuchi, Hirosato; Fujio, Koji

    2016-02-01

    The effects of stone composition on transurethral lithotripsy (TUL) have not been sufficiently elucidated. The purpose of this study was to identify how calcium phosphate stone composition impacts TUL. Two hundred eighty-nine cases of semi-rigid and/or flexible TUL for upper urinary tract calculi were reviewed retrospectively. Inclusion criteria were a preoperative assessment by noncontrast computed tomography (NCCT) and a stone composition analysis. Small stones and those without calcium composition were excluded. Stone core radiodensity (SCR) was measured by taking the average of the upper 3 of 5 points in the proximity of the center of the stone on NCCT. Fifty-three patients with calcium phosphate composition (CaP) and 118 patients with calcium oxalate and without phosphate composition were eligible for analysis. SCR was significantly higher in the CaP group (p<0.01). The CaP patient group needed a significantly longer operation time (p=0.014) and more laser energy (p=0.085), and tended to have a lower rate of complete lithotripsy (p=0.096) and higher incidence of postoperative pyelonephritis (p=0.181). Stones containing calcium phosphate are harder, demand more laser energy, and require a longer operating time. NCCT evaluation can estimate stone composition preoperatively, and may be a useful tool for predicting operative outcomes. PMID:26899606

  8. [Extracorporeal lithotripsy using the HM3 Dornier lithotriptor and the modified HM3 lithotriptor].

    PubMed

    Zanetti, G; Montanari, E; Mazza, L; Ceresoli, A; Mandressi, A; Pisani, E

    1989-12-01

    Extracorporeal shock waves lithotripsy is a well established procedure for the treatment of renal and ureteral calculi. From January 1985 to December 1987, 1034 patients underwent 1152 treatments with the Dornier HM3 lithotripter; from January 1988 and December 1988, 466 patients underwent 566 treatments with the modified Dornier HM3. Treatments with the original HM3 were performed mainly under general anaesthesia (97%). Only 2.4% of modified Dornier HM3 treatments have been performed under general anaesthesia; the 97.6% were treated under a combination of anxiolytic and analgesic drugs. An average of 1900 and 2300 shock waves was applied with the original HM3 and the modified one, respectively. The rate of secondary treatment increased from 10.3% to 17.4% respectively. At three month follow-up the 85.6% of the patients treated with the original HM3 and the 76.7% of those treated with the modified Dornier were free from stones. Low energy lithotripsy with the modified semi ellipsoid has proved to be equally effective as the older generators working with high shock wave pressure. PMID:2532400

  9. [Anesthesia for extracorporeal lithotripsy in the treatment of renal lithiasis].

    PubMed

    Darancette, G; Bourdalle-Badie, C; Robert, S

    1989-01-01

    Extracorporeal shock wave lithotripsy has become the main technique for treating renal lithiasis. It has many repercussions on anaesthesia. The fundamental technical concepts of lithotriptors are reviewed. The problems due to the different systems (electrohydraulic or piezoelectric--the most widespread in France) are discussed. Electrohydraulic systems, which are more adapted to the treatment of large stones (diameter greater than 2 cm), require the immersion of the patient. As a result, there are analgesic, cardiovascular, respiratory and temperature repercussions on the anaesthetic management of these patients. General anaesthesia is generally more appropriate for this technique. On the other hand, piezoelectric systems are more adapted to the treatment of medium-sized or small calculi (diameter less than 2 cm), and do not require immersion. Anaesthesia is often not required for the use of this technique, but, if necessary, local, regional or general anaesthesia may be used. For either technique, the anaesthetic protocol must be adapted to the patient's and the surgical indications. PMID:2683898

  10. A novel ureter dilatation method for replacing hydromantic perfusion pump during ureteroscopic lithotripsy in patients with ureteral calculi and ibroepithelial polyps.

    PubMed

    Li, Tengcheng; Fang, Youqiang; Wu, Jieying; Zhou, Xiangfu

    2014-01-01

    This study aimed to evaluate the clinical value of a novel ureter dilatation method during ureteroscopic pneumatic lithotripsy in patients with ureteral calculi and polyps. Clinical information of 86 patients with ureter calculi and polyps who underwent ureteroscopic pneumatic lithotripsy was reviewed. A cavity-distention machine was used in 44 cases to inject normal saline for keeping clear operation view (cavity-distention machine-assisted group). A high handled water bag with artificial water injection (traditional pneumatic lithotripsy group) was used in 42 cases. The total operation time, time of stone removal, stone clearance rate and surgery complications were compared between two groups. All operations were successful with no patients transferred to open surgery. No ureter breakage or avulsion occurred in two groups. Two patients in traditional pneumatic lithotripsy group suffered from ureter perforation. In cavity-distention machine-assisted group and traditional pneumatic lithotripsy group, the total operation time was 30.1±4.8 min and 36.2±6.0 min, respectively (t=-5.22, P<0.01); the time of stone removal was 6.4±1.3 min and 9.3±1.5 min, respectively (t=-9.59, P<0.01); the stone clearance rate was 100% (44/44) and 95.2% (40/42; upper ureter stone immigrated to the renal pelvis in 2, and extraorgan shock wave lithotripsy was performed), respectively. Thus, intraoperative infusion of saline with a cavity-distention machine may replace the hydromantic perfusion pump to maintain a clear operation view and favor the stone removal in lesser time. This method has important clinical value in the treatment of ureteral calculi and polyps. PMID:24753755

  11. Experimental Study of the Richtmyer-Meshkov Instability Induced by Cylindrical Converging Shock Waves

    NASA Astrophysics Data System (ADS)

    Si, Ting; Zhai, Zhigang; Luo, Xisheng; Yang, Jiming

    The Richtmyer-Meshkov (RM) instability induced by converging shock waves becomes more and more attractive because of its physical applications in shock-wave lithotripsy, inertial confinement fusion, turbulent mixing in scramjet and collapse in supernova.

  12. Biological consequences of fiber fragmentation with pulsed laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Bruhn, Erich W.; Go, Peter M. N. Y. H.; McClane, Robert W.; Hunter, John G.; Straight, Richard C.

    1990-06-01

    Fiber tip breakage during urinary and biliary laser lithotripsy has been recognized to occur with several laser types. This phenomenon has also been seen with Q-switched Nd:YAG laser lithotripsy. Our aim was to determine the biological consequences of this event in the canine ureter and bile duct. In an excised tissue preparation, urinary and biliary stones were impacted in a canine ureter and common bile duct. Three and four hundred micron quartz laser fibers were placed in direct contact with the stone. Normal saline coaxial irrigation was initiated at 75 xal/min. A Q-switched Nd:YAG laser was activated at repetition rates from 1O-30 Hz. and pulse energies from 10-30 mJ. The tissue was sectioned and microscopic examination of the fragmentation site was performed. Histological exam revealed the persistence of large numbers of fiber fragments in the lumen and imnbedded in the epithelium at the lithotripsy site. Fragments varied greatly in size and appeared to have angular, sharp edges We conclude that irrigation can not be relied upon to remove the fiber fragments from the lithotripsy sites and that the biological consequences of fiber fragmentation may be greater than previously believed. Glass fragments "blown" into the epitheliumu will often result in glass granulomas, which may eventually cause obstruction of closed lumninal structures. This raises serious concern for the presence of any fiber breakage during laser lithotripsy.

  13. Management of lower pole renal stones: the devil is in the details

    PubMed Central

    Issi, Yasar; Onem, Kadir; Germiyanoglu, Cankon

    2016-01-01

    Shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (MIP) are highly effective treatment options for lower pole stones up to 2 cm. Selecting the best treatment modality represents a controversial area in urology, because each treatment methods have their own advantages and disadvantages. Donaldson and co-workers have recently published a very comprehensive review and meta-analysis to compare the benefits and harms of SWL, RIRS and PNL techniques. PMID:27047957

  14. Management of lower pole renal stones: the devil is in the details.

    PubMed

    Resorlu, Berkan; Issi, Yasar; Onem, Kadir; Germiyanoglu, Cankon

    2016-03-01

    Shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (MIP) are highly effective treatment options for lower pole stones up to 2 cm. Selecting the best treatment modality represents a controversial area in urology, because each treatment methods have their own advantages and disadvantages. Donaldson and co-workers have recently published a very comprehensive review and meta-analysis to compare the benefits and harms of SWL, RIRS and PNL techniques. PMID:27047957

  15. Effect of alpha1-blockers on stentless ureteroscopic lithotripsy

    PubMed Central

    Zhu, Jianguo; Liang, Yuxiang; Chen, Weihong; Xu, Shuxiong; Wang, Yuanlin; Hu, Jianxing; He, Hui-chan; Zhong, Wei-de; Sun, Zhaolin

    2016-01-01

    ABSTRACT Objective To evaluate the clinical efficiency of alpha1-adrenergic antagonists on stentless ureteroscopic lithotripsy treating uncomplicated lower ureteral stones. Materials and Methods From January 2007 to January 2013, 84 patients who have uncomplicated lower ureteral stones treated by ureteroscopic intracorporeal lithotripsy with the holmium laser were analyzed. The patients were divided into two groups, group A (44 patients received indwelled double-J stents) and group B (40 patients were treated by alpha1-adrenergic antagonists without stents). All cases of group B were treated with alpha1 blocker for 1 week. Results The mean operative time of group A was significantly longer than group B. The incidences of hematuria, flank/abdominal pain, frequency/urgency after surgery were statistically different between both groups. The stone-free rate of each group was 100%. Conclusions The effect of alpha1-adrenergic antagonists is more significant than indwelling stent after ureteroscopic lithotripsy in treating uncomplicated lower ureteral stones. PMID:27136474

  16. Massive Pulmonary Calculi Embolism: A Novel Complication of Pneumatic Lithotripsy

    PubMed Central

    Zhang, Lin; Zhou, Yiwu

    2015-01-01

    Abstract Pneumatic lithotripsy is a minimally invasive technique mainly for the treatment of urinary staghorn stones. Previous literatures have reported some therapeutic complications during or after this procedure, but calculi embolism has not been mentioned before. We report here a fatal case of calculi-induced pulmonary embolism in an adult woman who underwent pneumatic lithotripsy. An autopsy did not reveal any evidence of pulmonary embolism. However, light microscopy revealed noticeable presence of calculi in pulmonary arterioles and capillaries, as evidenced by environmental scanning electron microscope and energy dispersive X-ray analysis. The primary determinants of calculi embolism include intrarenal pressure, and volume and viscosity of the calculi fragments formation. Vascular intravasation of smashed calculi might increase pulmonary vascular resistance and hypoxemia and decrease cardiac output. This case report intends to provide information for clinicians to consider the probability of intraoperative calculi embolism during lithotripsies when patients develop typical symptoms of acute pulmonary embolism. PMID:26222867

  17. Observations of the collapses and rebounds of millimeter-sized lithotripsy bubbles.

    PubMed

    Kreider, Wayne; Crum, Lawrence A; Bailey, Michael R; Sapozhnikov, Oleg A

    2011-11-01

    Bubbles excited by lithotripter shock waves undergo a prolonged growth followed by an inertial collapse and rebounds. In addition to the relevance for clinical lithotripsy treatments, such bubbles can be used to study the mechanics of inertial collapses. In particular, both phase change and diffusion among vapor and noncondensable gas molecules inside the bubble are known to alter the collapse dynamics of individual bubbles. Accordingly, the role of heat and mass transport during inertial collapses is explored by experimentally observing the collapses and rebounds of lithotripsy bubbles for water temperatures ranging from 20 to 60 °C and dissolved gas concentrations from 10 to 85% of saturation. Bubble responses were characterized through high-speed photography and acoustic measurements that identified the timing of individual bubble collapses. Maximum bubble diameters before and after collapse were estimated and the corresponding ratio of volumes was used to estimate the fraction of energy retained by the bubble through collapse. The rebounds demonstrated statistically significant dependencies on both dissolved gas concentration and temperature. In many observations, liquid jets indicating asymmetric bubble collapses were visible. Bubble rebounds were sensitive to these asymmetries primarily for water conditions corresponding to the most dissipative collapses. PMID:22088027

  18. Adaptable Design Improvements for Electromagnetic Shock Wave Lithotripters and Techniques for Controlling Cavitation

    NASA Astrophysics Data System (ADS)

    Smith, Nathan Birchard

    In this dissertation work, the aim was to garner better mechanistic understanding of how shock wave lithotripsy (SWL) breaks stones in order to guide design improvements to modern electromagnetic (EM) shock wave lithotripters. To accomplish this goal, experimental studies were carefully designed to isolate mechanisms of fragmentation, and models for wave propagation, fragmentation, and stone motion were developed. In the initial study, a representative EM lithotripter was characterized and tested for in vitro stone comminution efficiency at a variety of field positions and doses using phantom kidney stones of variable physical properties, and in different fluid mediums to isolate the contribution of cavitation. Through parametric analysis of the acoustic field measurements alongside comminution results, a logarithmic correlation was determined between average peak pressure incident on the stone surface and comminution efficiency. It was also noted that for a given stone type, the correlations converged to an average peak pressure threshold for fragmentation, independent of fluid medium in use. The correlation of average peak pressure to efficacy supports the rationale for the acoustic lens modifications, which were pursued to simultaneously enhance beam width and optimize the pulse profile of the lithotripter shock wave (LSW) via in situ pulse superposition for improved stone fragmentation by stress waves and cavitation, respectively. In parallel, a numerical model for wave propagation was used to investigate the variations of critical parameters with changes in lens geometry. A consensus was reached on a new lens design based on high-speed imaging and stone comminution experiments against the original lens at a fixed acoustic energy setting. The results have demonstrated that the new lens has improved efficacy away from the focus, where stones may move due to respiration, fragmentation, acoustic radiation forces, or voluntary patient movements. Using the traditional theory of brittle fragmentation and newfound understanding of average peak pressure correlation to stone comminution, the entire set of stone comminution data for lens comparison was heuristically modeled using a Weibull-style distribution function. This model linked both the average peak pressure and shock wave dose to efficacy, including their respective threshold parameters, and demonstrated correlation of coefficients to cavitation activity. Subsequently, this model was used in prediction of stone comminution efficiency from mimicked respiratory motions in vitro, which compared favorably to actual simulated motion studies using both the new and original lenses. Under a variety of mimicked respiratory motions, the new lens produced statistically higher stone comminution efficiency than the original lens. These results were confirmed in vivo in a swine model, where the new lens produced statistically higher stone comminution after 1,000 and 2,000 shocks. Finally, a mechanistic investigation into the effects of cavitation with the original lens was conducted using an integrated, self-focusing annular ring transducer specially designed for tandem pulse lithotripsy. It was found that cavitation and stone comminution efficiency are progressively enhanced by tandem pulsing as source energies of both the primary LSW and trailing pressure pulse increase, which suggests that cavitation and stress waves act synergistically to enhance the efficacy in kidney stone fragmentation.

  19. [Extracorporeal lithotripsy in a young child. Use of the EDAP LT 01 apparatus in a 20-month-old girl].

    PubMed

    Alessandrini, P; Coulange, C; Ovalles, J; Hernandez, F; Aubrespy, P

    1988-01-01

    The possibility for treating adults with renal stone by extracorporeal shock wave lithotripsy is proved to be an effective method. However, up to now, a few cases in the world were reported in childhood, never before the patient was 3 years old; although 65% of urinary stones in children can be observed before 3 years. We report the first successful application of the EDAP lithotriptor in the management of a twenty months little girl with upper urinary stone. We conclude that this treatment must be developed in future. PMID:3168100

  20. Sound field prediction of ultrasonic lithotripsy in water with spheroidal beam equations

    NASA Astrophysics Data System (ADS)

    Zhang, Lue; Wang, Xiang-Da; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2015-01-01

    With converged shock wave, extracorporeal shock wave lithotripsy (ESWL) has become a preferable way to crush human calculi because of its advantages of efficiency and non-intrusion. Nonlinear spheroidal beam equations (SBE) are employed to illustrate the acoustic wave propagation for transducers with a wide aperture angle. To predict the acoustic field distribution precisely, boundary conditions are obtained for the SBE model of the monochromatic wave when the source is located on the focus of an ESWL transducer. Numerical results of the monochromatic wave propagation in water are analyzed and the influences of half-angle, fundamental frequency, and initial pressure are investigated. According to our results, with optimization of these factors, the pressure focal gain of ESWL can be enhanced and the effectiveness of treatment can be improved. Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921504 and 2011CB707902), the National Natural Science Foundation of China (Grant No. 11274166), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201401), and the China Postdoctoral Science Foundation (Grant No. 2013M531313).

  1. Control of acoustic cavitation with application to lithotripsy

    NASA Astrophysics Data System (ADS)

    Bailey, Michael Rollins

    Control of acoustic cavitation, which is sound-induced growth and collapse of bubbles, is the subject of this dissertation. Application is to extracorporeal shock wave lithotripsy (ESWL), used to treat kidney stones. Cavitation is thought to help comminute stones yet may damage tissue. Can cavitation be controlled? The acoustic source in a widely used clinical lithotripter is an electrical spark at the near focus of an underwater ellipsoidal reflector. To control cavitation, we used rigid reflectors, pressure release reflectors, and pairs of reflectors aligned to have a common focus and a controlled delay between sparks. Cavitation was measured with aluminum foil, which was placed along the axis at the far focus of the reflector(s). Collapsing bubbles pitted the foil. Pit depth measured with a profilometer provided a relative measure of cavitation intensity. Cavitation was also measured with a focused hydrophone, which detected the pressure pulse radiated in bubble collapse. Acoustic pressure signals produced by the reflectors were measured with a PVdF membrane hydrophone, digitally recorded, and input into a numerical version of the Gilmore equation (F. R. Gilmore, 'The growth or collapse of a spherical bubble in a viscous compressible liquid,' Rep#26-4, California Institute of Technology, Pasadena (1952), pp.1-40.). Maximum pressure produced in a spherical bubble was calculated and employed as a relative measure of collapse intensity. Experimental and numerical results demonstrate cavitation can be controlled by an appropriately delayed auxiliary pressure pulse. When two rigid-reflector pulses are used, a long interpulse delay (150-200 μs) of the second pulse 'kicks' the collapsing bubble and intensifies cavitation. Foil pit depth and computed pressure three times single pulse values were obtained. Conversely, a short delay (<90 μs) 'stifles' bubble growth and weakens cavitation. A single pressure release reflector time- reverses the rigid-reflector waveform-a positive pressure spike follows a shallow negative phase-and thus inherently stifles cavitation. Additional configurations and waveforms were explored, and localization of an intensified cavitation region surrounded by a tempered cavitation region was realized. The general methods of control and their specific implementations provide tools for assessment of cavitation's role in, and for improvement of, ESWL.

  2. Hazardous sound levels produced by extracorporeal shock wave lithotripsy

    SciTech Connect

    Lusk, R.P.; Tyler, R.S.

    1987-06-01

    Sound emitted from the Dornier system GmbH lithotriptor was found to be of sufficient intensity to warrant concern about noise-induced sensorineural hearing loss. The patients were exposed to impulses of 112 dB. peak sound pressure level. Operating room personnel were exposed to sounds of less intensity, although the number of impulses they were exposed to was much greater, thereby increasing the risk of hearing loss. Hearing protection is recommended for patients and operating room personnel.

  3. Treatment philosophy and retreatment rates following piezoelectric lithotripsy.

    PubMed

    Fegan, J; Camp, L A; Wilson, W T; Miller, G L; Preminger, G M

    1993-01-01

    Second generation lithotriptors offer the advantage of anesthesia-free fragmentation of renal and ureteral calculi but they frequently require multiple treatments to attain a stone-free status. However, excessive single lithotripsy sessions or multiple treatments may be associated with significant damage to the kidney. For some clinicians a common treatment philosophy involves evaluation of serial plain abdominal films every 24 hours after lithotripsy and immediate retreatment of all patients with incomplete fragmentation. To avoid unnecessary retreatments and, thus, minimize potential renal damage, we prospectively evaluated 100 patients undergoing lithotripsy on a Wolf Piezolith 2300 device. Patients were routinely treated with 4,000 shocks at 1,100 bar. Serial plain abdominal films were obtained at 1 day and 2 weeks after lithotripsy. The need for retreatment was determined by the plain abdominal film results. Additional therapy was considered necessary if there was no stone fragmentation or if residual fragments measured greater than 4 mm. Of the patients whose plain abdominal film at 24 hours indicated the need for a repeat treatment 43% were stone-free on the 2-week film. Thus, these patients were spared an unnecessary treatment by allowing adequate time for the stone fragments to pass spontaneously. Our data suggest that repeat treatments on second generation lithotriptors should not be performed within 24 hours. Rather, the patient should be reevaluated at least 1 to 2 weeks later to avoid unnecessary retreatment with the attendant potential for renal injury. In addition, when comparing the retreatment rates of various lithotriptors, one should also consider the treatment philosophy used at the particular institution and the timing of the radiographic studies used to determine the stone-free status. PMID:8417191

  4. Retrograde intrarenal lithotripsy for small renal stones in prepubertal children.

    PubMed

    Abu Ghazaleh, Lara Alex; Shunaigat, Abdul Naser; Budair, Zahran

    2011-05-01

    Advancements in ureteroscopy have now given the urologist virtually unrestricted access to calculi at all locations in the upper urinary tract. Retrograde intrarenal lithotripsy is a new modality to treat upper urinary tract stones in children. In this retrospective study, we present our experience in retrograde intra-renal lithotripsy in children over a period of 30 months. Fifty-six children with renal stones less than 1.5 cm in size, who underwent retrograde intrarenal lithotripsy during the period from January 2007 to June 2009 at Prince Hussein Urology Center, Royal Medical Center, Amman, Jordan, were included in the study. The average age was 8.2 years and male to female ratio was 2.1:1. The average size of the stone was 1.2 cm, ranging from 0.9 to 1.5 cm. Twelve patients (15.5%) had bilateral stones. All patients had a Double J stent inserted 2-4 weeks prior to the procedure. Ureteroscopy up to the renal pelvis was performed and fragmentation of the pelvic stones was performed by electrohydraulic lithotriptor and the patients were on follow-up during this period. Overall, a total of 78 procedures were performed in these patients. Twelve patients underwent bilateral procedures for bilateral disease, but in separate settings. Nine patients (16%) needed a second session for residual stones. Only four patients (7.1%) needed a third session. The clearance rate was 94.8%. Three patients (3.9%) developed upper urinary tract infection after ureteroscopy; one patient (1.7%) developed frank hematuria postoperatively that was treated conservatively. No residual stones or other complications were detected during an average of 34 months of follow-up. Thus, in the expanding field of pediatric urolithiasis, retrograde intrarenal lithotripsy seems promising and is less invasive and has fewer complications. PMID:21566306

  5. Influence of Saline on Temperature Profile of Laser Lithotripsy Activation

    PubMed Central

    Silva, Igor N.; Donalisio da Silva, Rodrigo; Gustafson, Diedra; Sehrt, David; Kim, Fernando J.

    2015-01-01

    Abstract Purpose: We established an ex vivo model to evaluate the temperature profile of the ureter during laser lithotripsy, the influence of irrigation on temperature, and thermal spread during lithotripsy with the holmium:yttrium-aluminum-garnet (Ho:YAG) laser. Materials and Methods: Two ex vivo models of Ovis aries urinary tract and human calcium oxalate calculi were used. The Open Ureteral Model was opened longitudinally to measure the thermal profile of the urothelium. On the Clinical Model, anterograde ureteroscopy was performed in an intact urinary system. Temperatures were measured on the external portion of the ureter and the urothelium during lithotripsy and intentional perforation. The lithotripsy group (n=20) was divided into irrigated (n=10) and nonirrigated (n=10), which were compared for thermal spread length and values during laser activation. The intentional perforation group (n=10) was evaluated under saline flow. The Ho:YAG laser with a 365 μm laser fiber and power at 10W was used (1J/Pulse at 10 Hz). Infrared Fluke Ti55 Thermal Imager was used for evaluation. Maximum temperature values were recorded and compared. Results: On the Clinical Model, the external ureteral wall obtained a temperature of 37.4°C±2.5° and 49.5°C±2.3° (P=0.003) and in the Open Ureteral Model, 49.7°C and 112.4°C with and without irrigation, respectively (P<0.05). The thermal spread along the external ureter wall was not statically significant with or without irrigation (P=0.065). During intentional perforation, differences in temperatures were found between groups (opened with and without irrigation): 81.8°±8.8° and 145.0°±15.0°, respectively (P<0.005). Conclusion: There is an increase in the external ureteral temperature during laser activation, but ureteral thermal values decreased when saline flow was applied. Ureter thermal spread showed no difference between irrigated and nonirrigated subgroups. This is the first laser lithotripsy thermography study establishing the framework to evaluate the temperature profile in the future. PMID:25154455

  6. Minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy for calculus in bladder diverticula

    PubMed Central

    GU, SI-PING; YOU, ZHI-YUAN; HUANG, YUNTENG; LU, YI-JIN; HE, CAOHUI; CAI, XIAO-DONG; ZHOU, XIAO-MING

    2013-01-01

    The aim of this study was to investigate the effectiveness of minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy for treating calculus in bladder diverticula. Percutaneous cystostomy with ureteroscopic pneumatic lithotripsy was performed on six elderly male patients with calculi in bladder diverticula, who could not be treated with transurethral ureteroscopic lithotripsy. The stones were successfully removed from all patients, with no complications such as bladder perforation, rupture, urethritis or cystitis. The surgery time was 15–60 min, with an average time of 32 min. Postoperative ultrasound or X-ray examination showed no stone residues and the bladder stoma healed well. No recurrent stones were detected in the follow-up of 3–24 months (average, 16 months). Minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy is a safe, efficient and easy treatment for calculus in bladder diverticula. This method provides a new clinical approach for lithotripsy and we suggest that it is worthy of wider use. PMID:23837044

  7. Laser and acoustic lens for lithotripsy

    DOEpatents

    Visuri, Steven R.; Makarewicz, Anthony J.; London, Richard A.; Benett, William J.; Krulevitch, Peter; Da Silva, Luiz B.

    2002-01-01

    An acoustic focusing device whose acoustic waves are generated by laser radiation through an optical fiber. The acoustic energy is capable of efficient destruction of renal and biliary calculi and deliverable to the site of the calculi via an endoscopic procedure. The device includes a transducer tip attached to the distal end of an optical fiber through which laser energy is directed. The transducer tip encapsulates an exogenous absorbing dye. Under proper irradiation conditions (high absorbed energy density, short pulse duration) a stress wave is produced via thermoelastic expansion of the absorber for the destruction of the calculi. The transducer tip can be configured into an acoustic lens such that the transmitted acoustic wave is shaped or focused. Also, compressive stress waves can be reflected off a high density/low density interface to invert the compressive wave into a tensile stress wave, and tensile stresses may be more effective in some instances in disrupting material as most materials are weaker in tension than compression. Estimations indicate that stress amplitudes provided by this device can be magnified more than 100 times, greatly improving the efficiency of optical energy for targeted material destruction.

  8. Comparison of Percutaneous Nephrolithotomy Using Pneumatic Lithotripsy (Lithoclast®) Alone or in Combination with Ultrasonic Lithotripsy

    PubMed Central

    Cho, C one; Yu, Ji Hyeong; Sung, Luck Hee; Chung, Jae Yong

    2010-01-01

    Purpose Percutaneous nephrolithotomy (PCNL) is the procedure of choice for treating large renal stones. Pneumatic lithotripsy (Lithoclast®) is effective regardless of the stones' composition, and ultrasonic lithotripsy allows the aspiration of small debris during lithotripsy. We investigated the efficacy and safety of PCNL via Lithoclast® alone or combined with ultrasonic lithotripsy. Materials and Methods Thirty-five (group A) and 39 (group B) patients underwent Lithoclast® PCNL and combination therapy, respectively, from May 2001 to March 2010, and the two groups were compared in terms of stone size, location, and composition; operative time; average number of treatments; hospital days; hemoglobin loss; ancillary procedures; rate of device failure; and initial and total stone-free rates. Results The two groups did not differ significantly in preoperative stone size, location, or composition; the average number of treatments; or the initial and overall stone-free rates. However, combination therapy was associated with a significantly lower operative time (181±50 vs. 221±65 min, respectively, p=0.004), number of hospital days (11.6±3.8 vs. 14.2±4.4 days, respectively, p=0.009), and average hemoglobin loss (1.12±0.61 vs. 1.39±1.02 g/dl, respectively, p=0.013). Transfusions were required in 6 patients (4 and 2 in each group, respectively), but there were no significant complications related to percutaneous access. There were 2 (5.7%) mechanical failures (Lithoclast® probe fracture) in the group A and 5 (12.8%) in the group B (2 cases of suction tube obstruction, 3 cases of overheating). Conclusions The combination of ultrasonic lithotripter and Lithoclast® is more effective than Lithoclast® alone because it significantly decreases operative time, hemoglobin loss, and the hospital stay. This may reflect the superior power of Lithoclast® and the ability to aspirate the debris during ultrasonic lithotripsy. PMID:21165200

  9. Quantification of the Range of Motion of Kidney and Ureteral Stones During Shockwave Lithotripsy in Conscious Patients.

    PubMed

    Harrogate, Suzanne R; Yick, L M Shirley; Williams, James C; Cleveland, Robin O; Turney, Benjamin W

    2016-04-01

    Effective shockwave lithotripsy requires accurate targeting of the stone throughout the course of treatment. Stone movement secondary to respiratory movement can make this more difficult. In vitro work has shown that stone motion outside the focal region reduces the efficacy of stone fragmentation; however, there are few clinical data on the degree of stone movement in patients during treatment. To investigate this, X-ray fluoroscopic images of the kidney and ureteral stones at the upper and lower limits of the normal respiratory cycle were acquired during shock wave lithotripsy of 58 conscious patients, and stone excursion was calculated from these images. In addition, the respiration rate and patient perceived pain were recorded during the course of the treatment. It was found that stone motion secondary to respiration was 7.7 ± 2.9 mm for kidney stones and 3.6 ± 2.1 mm for ureteral stones-less than has been reported in studies with anesthetized patients. There was no significant change of motion over the course of treatment although pain was found to increase. These data suggest that stone motion in conscious patients is less than in anesthetized patients. Furthermore, it suggests that lithotripters with focal regions of 8 mm or greater should not suffer from a marked drop in fragmentation efficiency due to stone motion. PMID:26756226

  10. Intracorporeal lithotripsy with the holmium:YAG laser

    NASA Astrophysics Data System (ADS)

    Denstedt, John D.; Razvi, Hassan A.; Chun, Samuel S.; Sales, Jack L.

    1995-05-01

    A variety of devices are currently available for intracorporeal stone fragmentation. Recently a new wavelength of laser, the Holmium:YAG, has demonstrated a variety of potential urologic applications including ablation of soft tissue lesions as well as stone fragmentation. This laser has a wavelength of 2100 nm and operates in a pulsed mode. Energy is delivered through a 400 um quartz end-firing fiber. In this presentation we review our clinical experience with the Holmium:YAG laser for the treatment of renal and ureteral calculi. Over a 23 month period, 63 patients underwent 67 procedures. Seven procedures consisted of percutaneous nephrolithotripsy for large or staghorn renal calculi. Sixty procedures were performed for ureteral stones. Procedures for proximal ureteral stones (6) employed a retrograde approach using flexible ureteroscopes (8.5 or 9.8). Stones in the mid ureter (12) and distal ureter (42) were approached transurethrally using a 6.9 rigid ureteroscope. Complete stone fragmentation without the need for additional procedures was achieved in 82% of cases. Treatment failures included 1 stone migration into the renal pelvis during laser activation, 6 patients who had incomplete fragmentation and 3 patients in which laser malfunction precluded complete fragmentation. Stone analysis available in 23 patients revealed calcium oxalate monohydrate (15), calcium oxalate dihydrate (2), cystine (2), uric acid (3) and calcium phosphate (1). A single complication of ureteral perforation occurred when the laser was fired without direct visual guidance. Radiographic follow-up at an average of 16 weeks is available in 22 patients and has identified 2 patients with ureteral strictures that are not believed to be related to laser lithotripsy. In summary, we have found the Holmium:YAG laser to be a reliable and versatile device for intracorporeal lithotripsy. Its safety and efficacy make it a suitable alternative for performing intracorporeal lithotripsy of urinary calculi.

  11. [Extracorporeal shockwave lithotripsy. Current status in treatment of kidney calculus disease].

    PubMed

    Rassweiler, J; Eisenberger, F; Bub, P; Schmidt, A

    1989-08-10

    The introduction of extracorporal shock wave lithotripsy has led to a revolution in stone management. After five years of clinical experience with increasing use of second generation lithotripters, the following conclusions can be drawn: There is an increasing tendency to employ ESWL for ureteral calculi, although only 60% of those can be located by ultrasound. In the case of staghorn stones, a differentiated approach is adopted (ESWL-, PCNL-monotherapy or a combination of the two) depending on stone size, localisation, chemical composition, radiodensity, and the state of the collecting system. With almost all second generation lithotripters, ESWL can be performed under i.v.-analgesia. Some machines with a large-aperture shock wave source (i.e. Wolf Piezolith, Edap LT 01, Dornier MPL 9000) even permit painfree treatment without the need for analgesia. However, this is associated with a 30% increase in retreatment rate. Further development of low-cost lithotripters and increasing use of ESWL for biliary stones make it necessary for ever more hospitals to face the question of installing such a machine. In this situation, the choice must be based on the local situation (i.e. number of patients, interdisciplinary use of ESWL). PMID:2670718

  12. Factors Influencing Urologist Treatment Preference in Surgical Management of Stone Disease

    PubMed Central

    Childs, M. Adam; Rangel, Laureano J.; Lingeman, James E.; Krambeck, Amy E.

    2015-01-01

    Objective To assess the surgeon factors influencing the surgical treatment decisions for symptomatic stone disease. The factors influencing the selection of shock wave lithotripsy (SWL), ureteroscopy, or percutaneous nephrolithotomy to treat symptomatic stone disease are not well studied. Methods Electronic surveys were sent to urologists with American Medical Association membership. Information on training, practice, and ideal treatment of common stone scenarios was obtained and statistically analyzed. Results In November 2009, 600 surveys were sent and 180 were completed. High-volume SWL practices (>100 cases annually) were more common in community practice (P < .01), and high-volume ureteroscopy and percutaneous nephrolithotomy practices were more common in academic practice (P = .03). Community practice was associated with SWL selection for proximal urolithiasis and upper pole nephrolithiasis (P < .005). An increasing time since urologic training was associated with SWL selection for proximal urolithiasis and upper pole nephrolithiasis (P < .01). Urologists reporting shock wave lithotriptor ownership were 3-4 times more likely to select SWL for urolithiasis or nephrolithiasis compared with urologists who did not own a lithotripter (P < .01). Routine concern for stent pain and rigid ureteroscope preference (vs flexible) were associated with SWL selection (P < .03). Conclusion Surgeon factors significantly affected urolithiasis treatment selection. SWL was associated with community urology practice, increasing time since training, shock wave lithotriptor ownership, concern for stent pain, and ureteroscope preference. PMID:22245295

  13. Holmium: YAG laser lithotripsy versus pneumatic lithotripsy for treatment of distal ureteral calculi: a meta-analysis.

    PubMed

    Yin, Xiangrui; Tang, Ziwei; Yu, Bei; Wang, Yarong; Li, Yuehua; Yang, Qi; Tang, Wei

    2013-04-01

    The objective of this study was to estimate the treatment effect of Pneumatic Lithotripsy (PL) versus holmium: YAG laser lithotripsy (LL) in the treatment of distal ureteric calculi. A bibliographic search covering the period from 1990 to April 2012 was conducted using search engines such as MEDLINE, EMBASE, and Cochrane library. Data were extracted and analyzed with RevMan5.1 software. A total of 47 studies were scant, and 4 independent studies were finally recruited. Holmium: YAG LL conveyed significant benefits compared with PL in terms of early stone-free rate [odds ratio (OR)=4.42, 95% confidence interval (CI) (1.14, 17.16), p=0.03], delayed stone-free rate [OR=4.42, 95%CI (1.58, 12.37), p=0.005], mean operative time [WMD=-16.86, 95%CI (-21.33, -12.39), p<0.00001], retaining double-J catheter rate [OR=0.44, 95%CI (0.25, 0.78), p=0.004], and stone migration incidence [OR=0.26, 95%CI (0.11, 0.62), p=0.003], but not yet in the postoperative hematuria rate and the ureteral perforation rate according to this meta-analysis. Precise estimates on larger sample size and trials of high quality may provide more uncovered outcomes in the future. PMID:23016622

  14. Shock-induced collapse of a gas bubble in shockwave lithotripsy

    PubMed Central

    Johnsen, Eric; Colonius, Tim

    2008-01-01

    The shock-induced collapse of a pre-existing nucleus near a solid surface in the focal region of a lithotripter is investigated. The entire flow field of the collapse of a single gas bubble subjected to a lithotripter pulse is simulated using a high-order accurate shock- and interface-capturing scheme, and the wall pressure is considered as an indication of potential damage. Results from the computations show the same qualitative behavior as that observed in experiments: a re-entrant jet forms in the direction of propagation of the pulse and penetrates the bubble during collapse, ultimately hitting the distal side and generating a water-hammer shock. As a result of the propagation of this wave, wall pressures on the order of 1 GPa may be achieved for bubbles collapsing close to the wall. The wall pressure decreases with initial stand-off distance and pulse width and increases with pulse amplitude. For the stand-off distances considered in the present work, the wall pressure due to bubble collapse is larger than that due to the incoming shockwave; the region over which this holds may extend to ten initial radii. The present results indicate that shock-induced collapse is a mechanism with high potential for damage in shockwave lithotripsy. PMID:19062841

  15. Thulium fiber laser lithotripsy in an in vitro ureter model

    NASA Astrophysics Data System (ADS)

    Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

    2014-12-01

    Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ=2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy.

  16. Extracorporeal shockwave lithotripsy of gallstones. Possibilities and limitations.

    PubMed Central

    Vergunst, H; Terpstra, O T; Brakel, K; Laméris, J S; van Blankenstein, M; Schröder, F H

    1989-01-01

    Recently extracorporeal shockwave lithotripsy (ESWL) has been introduced as a nonoperative treatment for gallstone disease. Except for lung damage, no significant adverse effects of ESWL of gallbladder stones have been observed in animals. In clinical use ESWL of gallbladder stones is now confined to 15% to 30% of symptomatic patients. To achieve complete stone clearance, ESWL of gallbladder stones must be supplemented by an adjuvant therapy. ESWL of bile duct stones is highly effective and can be considered in patients in whom primary endoscopic or surgical stone removal fails. Second generation lithotriptors allow anesthesia-free (outpatient) treatments, but the clinical experience with most of these ESWL devices is still limited. The likelihood of gallbladder stone recurrence is a major disadvantage of ESWL treatment, which raises the issue of cost-effectiveness. ESWL for cholelithiasis is a promising treatment modality with good short-term and unknown long-term results. PMID:2684058

  17. Laser lithotripsy for removal of uroliths in dogs

    NASA Astrophysics Data System (ADS)

    Adams, Larry G.; Lulich, Jody P.

    2006-02-01

    Introduction: This study evaluated the ability to fragment and remove naturally occurring uroliths in dogs using a holmium: YAG laser. Methods: Twenty four dogs with naturally occurring uroliths including 10 spayed females and 14 neutered males. The dogs were 8.7 +/- 2.8 years old and weighed 13.7 +/- 8.0 kg. All dogs had bladder stones and 5 male dogs also had urethral stones. In female dogs, cystoscopy was performed using a rigid cystoscope with sheath diameter of 14 to 19 french. Cystoscopy was performed in males dogs using a 7.5 french diameter pediatric ureteroscope. Uroliths were fragmented using a 20 watt Holmium: YAG laser and the fragments were removed by basket extraction and voiding urohydropropulsion. Results: Average laser parameters for urolith fragmentation were 0.7 Joules at 8 Hertz (range: 0.5 to 1.3 Joules at 5 to 13 Hertz). All urolith fragments were successfully removed in all 10 female dogs and 11 of 14 male dogs. In one male dog, the urethra was too small to allow passage of the ureteroscope. In one of the male dogs, the urethral stones were successfully removed by laser lithotripsy, but removal of the bladder stones was performed by cystotomy. There was one complication of urethral perforation during attempts to pass an access sheath transurethrally in a dog with extensive proliferative urethritis. Conclusions: Laser lithotripsy is a safe and effective method of removing bladder and urethral stones in dogs provided the dog is large enough to permit transurethral passage of a cystoscope or ureteroscope.

  18. Large Bowel Obstruction Due to a Big Gallstone Successfully Treated with Endoscopic Mechanical Lithotripsy

    PubMed Central

    Balzarini, Marco; Broglia, Laura; Comi, Giovanni; Calcara, Calcedonio

    2015-01-01

    Colonic gallstone ileus in an uncommon mechanical bowel obstruction caused by intraluminal impaction of one or more gallstones. The surgical management of gallstone ileus is complex and is potentially of high risk. There have been reports of gallstone extractions using various endoscopic modalities to relieve the obstruction. In this report we present the technique employed to successfully perform a mechanical lithotripsy and extraction of a large gallstone embedded in a sigmoid colon affected by diverticular stenosis. We passed through the stenosis with a 11.3 mm videoscope with 3.7 mm channel. A large lithotripsy extraction basket was used to catch and break up the stone and fragments were removed using the same basket. The patient was discharged asymptomatic three days after the procedure. Using appropriate devices mechanical lithotripsy is a safe and effective method to treat colonic obstruction and avoid surgery in the setting of gallstone ileus even in case of big stones. PMID:26137329

  19. Predictive Factors of the Outcome of Extracorporeal Shockwave Lithotripsy for Ureteral Stones

    PubMed Central

    Choi, Ji Woong; Song, Phil Hyun

    2012-01-01

    Purpose Extracorporeal Shock Wave Lithotripsy (ESWL) has shown successful outcomes for ureteral stones. We investigated predictive factors for failure of ESWL for treating ureteral stones. Materials and Methods A total of 153 patients who underwent ESWL between July 2006 and July 2009 for ureteral stones diagnosed by non-enhanced spiral computed tomography were divided into two groups: (group A, stone size ≤10 mm; and group B, stone size >10 mm). The failure was defined as remnant stones >4 mm. We assessed age, sex, body mass index, stone size, laterality, location, skin-to-stone distance (SSD), Hounsfield unit, and the presence of secondary signs (hydronephrosis, renal enlargement, perinephric fat stranding, and tissue rim sign). We analyzed predictive factors by using logistic regression in each group. Results The success rates were 90.2% and 68.6% in group A and B, respectively. In the univariate analysis of each group, stone size, SSD, and all secondary signs showed statistically significant differences in terms of the outcome of ESWL (p<0.05). In the multivariate logistic regression, stone size (odds ratio [OR], 50.005; 95% confidence interval [CI], 6.207 to 402.852) was an independent predictive factor in group A. The presence of perinephric fat standing (OR, 77.634; 95% CI, 1.349 to 446.558) and stone size (OR, 19.718; 95% CI, 1.600 to 243.005) were independent predictive factors in group B. Conclusions Stone size is an independent predictive factor influencing failure of ESWL for treating ureteral stones. In larger ureteral stones (>10 mm), the presence of perinephric fat stranding is also an independent predictive factor. PMID:22741053

  20. Ureteropyeloscopy and homium: YAG laser lithotripsy for treatment of ureteral calculi (report of 356 cases)

    NASA Astrophysics Data System (ADS)

    Wu, Zhong; Din, Qiang; Jiang, Hao-wen; Zen, Jing-cun; Yu, Jiang; Zhang, Yuanfang

    2005-07-01

    Objective: To evaluate the efficacy and safety of holmium YAG laser lithotripsy for the treatment of ureteral calculi. Methods: A total of 356 patients underwent ureteropyeloscopic lithotripsy using holmium YAG laser with a semirigid uretesopyeloscope, 93 upper, 135 middle, and 128 lower ureteral stones were treated. Results: The overall successful fragmentation rate for all ureteral stones in a single session achieved 98% (349/356). The successful fragmentation rate stratified by stone location was 95% 88/93 in the upper ureter, 99% (134/135) in the mid ureter , and 99%(127/128) in the distal ureter. 12 cases with bilateral ureteral stones which caused acute renal failure and anuria were treated rapidly and effectively by the holmium YAG laser lithotripsy. No complications such as perforation and severe trauma were encountered during the operations. 2 weeks 17months (with an average of 6.8 month ) follow up postoperatively revealed that the overall stone-free rate was 98%(343/349) and no ureteral stenosis was found. Conclusions Holmium YAG laser lithotripsy is a highly effective, minimally invasive and safe therapy for ureteral calculi. It is indicated as a first choice of treatment for patients with ureteral calculi, especially for the ones with mid- lower levels of ureteral calculi.

  1. Impact of Residual Fragments following Endourological Treatments in Renal Stones

    PubMed Central

    Acar, Cenk; Cal, Cag

    2012-01-01

    Today, shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), and flexible ureterorenoscopy (URS) are the most widely used modalities for the management of renal stones. In earlier series, treatment success of renal calculi assessed with KUB radiography, ultrasound, or intravenous pyelography which are less sensitive than CT that leads to be diversity of study results in reporting outcome. Residual fragments (RFs) after interventional therapies may cause pain, infection, or obstruction. The size and location of RFs following SWL and PCNL are the major predictors for clinical significant symptoms and stone events requiring intervention. There is no consensus regarding schedule for followup of SWL, PCNL, and flexible URS. Active monitoring can be recommended when the stones become symptomatic, increase in size, or need intervention. RFs <4 mm after SWL and <2 mm after PCNL and flexible URS could be actively monitored on an annual basis with CT. Early repeat SWL and second-look endoscopy are recommended after primary SWL and PCNL, respectively. There is insufficient data for flexible URS, but RFs can be easily treated with repeat URS. Finally, medical therapy should be tailored based on the stone analysis and metabolic workup that may be helpful to prevent regrowth of the RFs. PMID:22829812

  2. [Use of isradipine and lipostabil for protection of the kidney during extracorporeal lithotripsy].

    PubMed

    Neĭmark, A I; Zhukov, V N; Fidirkin, A V

    1998-01-01

    The authors analyse the effects of ESWL on renal function in 180 patients with nephrolithiasis. Renal performance was judged by the level of enzymes. Pharmacological defense of the kidney was made with isradipine and lipostabil given for 12 weeks before lithotripsy and 4 weeks after it. Isradipine proved a good corrector of renal function after lithotripsy as it decreased enzymuria, promoted normalization of the activity of alkaline phosphatase, gamma-glutamyl transferase, alpha-glucosidase and lactate dehydrogenase to the end of the first postoperative month. This indicates quicker recovery of renal parenchyma after ESWL. Lipostabil also improved enzymic indices. Its moderate protective action on renal parenchyma normalized levels of some enzymes one month after ESWL. PMID:10051821

  3. Optimal Management of Lower Polar Calyceal Stone 15 to 20 mm

    PubMed Central

    Haroon, Naveed; Nazim, Syed M

    2013-01-01

    Purpose To compare the stone clearance rate, efficiency quotient (EQ), and early complications of shock wave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) for solitary lower-pole renal stones measuring 15 to 20 mm. Materials and Methods This was a retrospective matched-pair analysis of 142 patients (78 in the SWL and 64 in the PCNL group). Preoperative imaging was done by use of noncontrast computed tomography (CT kidney, ureter, and bladder [KUB]), intravenous urogram, or plain X-ray and ultrasound KUB to assess the largest dimension of the stones. Only patients with radiopaque stones were included. The stone-free rates were assessed with plain X-ray and ultrasound at 4 weeks. Data were analyzed by use of SPSS ver. 19. Results The patients' demographic profiles (age, body mass index) and the stone sizes were comparable in the two groups. The mean stone size was 17.4±2.12 in the PCNL group compared with 17.67±2.04 in the SWL group (p=0.45). At 4 weeks, 83% of patients undergoing PCNL were stone-free compared with 51% in the SWL group (p<0.001). The EQ for the PCNL group was 76% compared with 44% for the SWL group (p<0.001). Ancillary procedures were required by 9% of patients in the PCNL group compared with 15% in the SWL group. The complication rate was 19% in both groups. The SWL complications were minor. Conclusions Stone clearance from the lower pole of solitary stones sized 15 to 20 mm at the greatest diameter following SWL is poorer. These calculi can be better managed with percutaneous surgery owing to its higher efficacy and acceptably low morbidity. PMID:23614064

  4. Treatment of Kidney Stone in a Kidney-Transplanted Patient with Mini-Percutaneous Laser Lithotripsy: A Case Report

    PubMed Central

    Markić, Dean; Krpina, Kristian; Ahel, Juraj; Gršković, Antun; Španjol, Josip; Rubinić, Nino; Materljan, Mauro; Mikolašević, Ivana; Orlić, Lidija; Rački, Sanjin

    2016-01-01

    We report a case of a kidney-transplanted patient with urolithiasis treated with mini-percutaneous laser lithotripsy. The patient presented with renal dysfunction and graft hydronephrosis. Diagnostic procedures revealed ureterolithiasis as a cause of obstruction, and percutaneous nephrostomy was inserted as a temporary solution. Before surgery, the stone migrated to the renal pelvis. Mini-percutaneous laser lithotripsy was successfully performed, and during surgery, all stone fragments were removed. Six months after successful treatment, the patient has good functioning and stone-free graft. PMID:27066492

  5. Percutaneous Endoscopic Holmium Laser Lithotripsy for Management of Complicated Biliary Calculi

    PubMed Central

    Healy, Kelly; Chamsuddin, Abbas; Spivey, James; Martin, Louis; Nieh, Peter

    2009-01-01

    Background and Objectives: Advances in endoscopic techniques have transformed the management of urolithiasis. We sought to evaluate the role of such urological interventions for the treatment of complex biliary calculi. Methods: We conducted a retrospective review of all patients (n=9) undergoing percutaneous holmium laser lithotripsy for complicated biliary calculi over a 4-year period (12/2003 to 12/2007). All previously failed standard techniques include ERCP with sphincterotomy (n=6), PTHC (n=7), or both of these. Access to the biliary system was obtained via an existing percutaneous transhepatic catheter or T-tube tracts. Endoscopic holmium laser lithotripsy was performed via a flexible cystoscope or ureteroscope. Stone clearance was confirmed intra- and postoperatively. A percutaneous transhepatic drain was left indwelling for follow-up imaging. Results: Mean patient age was 65.6 years (range, 38 to 92). Total stone burden ranged from 1.7 cm to 5 cm. All 9 patients had stones located in the CBD, with 2 patients also having additional stones within the hepatic ducts. All 9 patients (100%) were visually stone-free after one endoscopic procedure. No major perioperative complications occurred. Mean length of stay was 2.4 days. At a mean radiological follow-up of 5.4 months (range, 0.5 to 21), no stone recurrence was noted. Conclusions: Percutaneous endoscopic holmium laser lithotripsy is a minimally invasive alternative to open salvage surgery for complex biliary calculi refractory to standard approaches. This treatment is both safe and efficacious. Success depends on a multidisciplinary approach. PMID:19660213

  6. Evaluation of Extracorporeal Shock Wave Lithotripsy (ESWL): Efficacy in Treatment of Urinary System Stones

    PubMed Central

    Junuzovic, Dzelaludin; Prstojevic, Jelena Kovacevic; Hasanbegovic, Munira; Lepara, Zahid

    2014-01-01

    ABSTRACT Introduction: Elimination of stone is determined by size and its localization. Stone from the ureter in 80% of cases can be eliminated spontaneously. If the stone by its characteristics is not spontaneously eliminated, taken are further steps and therapeutic protocols to solve this problem. Material and methods: The study was prospective, open and comparative. It was conducted at the Urology Clinic Clinical Center of Sarajevo University in the period from 2007 to 2013. The study included 404 patients with urinary tract lithiasis treated by ESWL. ESWL treatment is performed on the machine Siemens Model Lithostar Multiline, which has a combined ultrasonographic and fluoroscopic display, large energy density in order to obtain optimum focus (without damaging surrounding tissue) and minimal pain that on rare occasions requires for mild sedation-sedation. Results: From a total of 404 patients included in the study there were 234 (57.92%) male and 170 (42.08%) female patients. The most common type of stone both in female and male patients was calcium type. From a total of 262 calcium stones, 105 of them (40.07%) was present in female patients and 157 (59.92%) in male. Share of infectious type of stone in female patients was 63 (49.60%) and 64 among males (50.39%). Other stones were less abundant in both the gender groups and their total number was only 17. In women their frequency was 2 (13.33%) and 13 among males (86.67%). There was a significant difference in the frequency of different types of stones by gender (x2 = 11.47, p = 0.009). Conclusion: There was no statistically significant correlation between the number of treatments and localization of stones in the ureter, as well as a statistically significant correlation between the size of the stone and the localization of calculus in the ureter. PMID:25568579

  7. Effect of lithotripter focal width on stone comminution in shock wave lithotripsy

    PubMed Central

    Qin, Jun; Simmons, W. Neal; Sankin, Georgy; Zhong, Pei

    2010-01-01

    Using a reflector insert, the original HM-3 lithotripter field at 20 kV was altered significantly with the peak positive pressure (p+) in the focal plane increased from 49 to 87 MPa while the −6 dB focal width decreased concomitantly from 11 to 4 mm. Using the original reflector, p+ of 33 MPa with a −6 dB focal width of 18 mm were measured in a pre-focal plane 15-mm proximal to the lithotripter focus. However, the acoustic pulse energy delivered to a 28-mm diameter area around the lithotripter axis was comparable (∼120 mJ). For all three exposure conditions, similar stone comminution (∼70%) was produced in a mesh holder of 15 mm after 250 shocks. In contrast, stone comminution produced by the modified reflector either in a 15-mm finger cot (45%) or in a 30-mm membrane holder (14%) was significantly reduced from the corresponding values (56% and 26%) produced by the original reflector (no statistically significant differences were observed between the focal and pre-focal planes). These observations suggest that a low-pressure∕broad focal width lithotripter field will produce better stone comminution than its counterpart with high-pressure∕narrow focal width under clinically relevant in vitro comminution conditions. PMID:20370044

  8. Shock Wave Technology and Application: An Update☆

    PubMed Central

    Rassweiler, Jens J.; Knoll, Thomas; Köhrmann, Kai-Uwe; McAteer, James A.; Lingeman, James E.; Cleveland, Robin O.; Bailey, Michael R.; Chaussy, Christian

    2012-01-01

    Context The introduction of new lithotripters has increased problems associated with shock wave application. Recent studies concerning mechanisms of stone disintegration, shock wave focusing, coupling, and application have appeared that may address some of these problems. Objective To present a consensus with respect to the physics and techniques used by urologists, physicists, and representatives of European lithotripter companies. Evidence acquisition We reviewed recent literature (PubMed, Embase, Medline) that focused on the physics of shock waves, theories of stone disintegration, and studies on optimising shock wave application. In addition, we used relevant information from a consensus meeting of the German Society of Shock Wave Lithotripsy. Evidence synthesis Besides established mechanisms describing initial fragmentation (tear and shear forces, spallation, cavitation, quasi-static squeezing), the model of dynamic squeezing offers new insight in stone comminution. Manufacturers have modified sources to either enlarge the focal zone or offer different focal sizes. The efficacy of extracorporeal shock wave lithotripsy (ESWL) can be increased by lowering the pulse rate to 60–80 shock waves/min and by ramping the shock wave energy. With the water cushion, the quality of coupling has become a critical factor that depends on the amount, viscosity, and temperature of the gel. Fluoroscopy time can be reduced by automated localisation or the use of optical and acoustic tracking systems. There is a trend towards larger focal zones and lower shock wave pressures. Conclusions New theories for stone disintegration favour the use of shock wave sources with larger focal zones. Use of slower pulse rates, ramping strategies, and adequate coupling of the shock wave head can significantly increase the efficacy and safety of ESWL. PMID:21354696

  9. Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy

    NASA Astrophysics Data System (ADS)

    Watterson, James D.; Girvan, Andrew R.; Beiko, Darren T.; Nott, Linda; Wollin, Timothy A.; Razvi, Hassan A.; Denstedt, John D.

    2003-06-01

    Objectives: Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy (PCN). Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy. The purpose of this study was to review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Methods: A retrospective analysis was conducted at 2 tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and 2 encrusted ureteral stents were treated. Mean gestational age at presentation was 22 weeks. Mean stone size was 8.1 mm. Stones were located in the proximal ureter/ureteropelvic junction (UPJ) (3), mid ureter (1), and distal ureter (6). Results: Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetrical or urological complications were encountered. Conclusions: Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

  10. Holmium:YAG laser lithotripsy for the management of urolithiasis in small ruminants and pot-bellied pigs

    NASA Astrophysics Data System (ADS)

    Halland, Spring K.; House, John K.; George, Lisle

    2001-05-01

    Obstructive urolithiasis is a common problem in small ruminants and pot-bellied pigs. The most common site of urinary tract obstruction in these species is the urethra. Surgical procedures developed to relieve obstructions, in our experience have been effective in approximately 75% of cases. Urethral stricture is a common complication if the mucosa of the urethra is disrupted. The objective of this project was to evaluate endoscopy guided laser lithotripsy as a therapeutic modality to relieve urethral obstructions in small ruminants and pot-bellied pigs. The study population consisted of patients presented to the Veterinary Medical Teaching Hospital at the University of California Davis with obstructive urolithiasis. Lithotripsy was performed using a Holmium:YAG laser via a 200-micron low water quartz fiber passed through a flexible mini-endoscope. Two types of urinary calculi were managed with this technique, calcium carbonate and calcium hydroxyphosphate. Laser lithotripsy was effective at relieving obstructions caused by both types of calculi when conventional methods had failed. Laser lithotripsy performed via urethral endoscopy is a safe and effective therapeutic modality for management of obstructive urolithiasis in small ruminants and pot-bellied pigs and reduces the risk of post procedural urethral stricture.

  11. Ureteroscopic Lithotripsy Using Swiss Lithoclast for Treatment of Ureteral Calculi: 12-Years Experience

    PubMed Central

    Park, Dong Soo

    2009-01-01

    Ureteroscopic lithotripsy using Swiss Lithoclast was performed in 411 cases from January 1996 to September 2007 in a single hospital. Medical records of 341 cases, in which Swiss Lithoclast was successfully applied, were available for this retrospective study. We used 9.5Fr and 10Fr Storz rigid ureteroscopes. A success was defined as being free of stone-related symptoms and residual stones larger than 2 mm. Sixty one stones were located in the upper ureter, 49 stones were in the mid ureter, and 231 stones were in the lower ureter. The overall success rate was 93.5%. The success rate of upper ureter stone (80.3%) was significantly lower compared with those of mid (93.8%) and lower (96.9%) ureter stones (P=0.001). The higher the calculi was located within the ureter, the more chance of upward migration there was (P<0.001). The success rate in male patients was lower than in female patients without a statistical significance (P=0.068). The success rate decreased as the size of the stone increased (P<0.001), and as the degree of hydronephrosis increased (P=0.03). Perforation rates were 4.9%, 4.1%, and 2.6% from upper to lower ureter stone group. Ureteroscopic lithotripsy using Swiss Lithoclast is a safe and useful treatment modality for ureteral calculi. PMID:19654954

  12. Detachable fiber optic tips for use in thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas C.; Blackmon, Richard L.; Irby, Pierce B.; Fried, Nathaniel M.

    2013-03-01

    The thulium fiber laser (TFL) has recently been proposed as an alternative to the Holmium:YAG (Ho:YAG) laser for lithotripsy. The TFL's Gaussian spatial beam profile provides higher power transmission through smaller optical fibers with reduced proximal fiber tip damage, and improved saline irrigation and flexibility through the ureteroscope. However, distal fiber tip damage may still occur during stone fragmentation, resulting in disposal of the entire fiber after the procedure. A novel design for a short, detachable, distal fiber tip that can fit into an ureteroscope's working channel is proposed. A prototype, twist-lock, spring-loaded mechanism was constructed using micromachining methods, mating a 150-μm-core trunk fiber to 300-μm-core fiber tip. Optical transmission measuring 80% was observed using a 30-mJ pulse energy and 500-μs pulse duration. Ex vivo human calcium oxalate monohydrate urinary stones were vaporized at an average rate of 187 μg/s using 20-Hz modulated, 50% duty cycle 5 pulse packets. The highest stone ablation rates corresponded to the highest fiber tip degradation, thus providing motivation for use of detachable and disposable distal fiber tips during lithotripsy. The 1-mm outer-diameter prototype also functioned comparable to previously tested tapered fiber tips.

  13. Detachable fiber optic tips for use in thulium fiber laser lithotripsy.

    PubMed

    Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

    2013-03-01

    The thulium fiber laser (TFL) has recently been proposed as an alternative to the Holmium:YAG (Ho:YAG) laser for lithotripsy. The TFL's Gaussian spatial beam profile provides higher power transmission through smaller optical fibers with reduced proximal fiber tip damage, and improved saline irrigation and flexibility through the ureteroscope. However, distal fiber tip damage may still occur during stone fragmentation, resulting in disposal of the entire fiber after the procedure. A novel design for a short, detachable, distal fiber tip that can fit into an ureteroscope's working channel is proposed. A prototype, twist-lock, spring-loaded mechanism was constructed using micromachining methods, mating a 150-μm-core trunk fiber to 300-μm-core fiber tip. Optical transmission measuring 80% was observed using a 30-mJ pulse energy and 500-μs pulse duration. Ex vivo human calcium oxalate monohydrate urinary stones were vaporized at an average rate of 187  μg/s using 20-Hz modulated, 50% duty cycle 5 pulse packets. The highest stone ablation rates corresponded to the highest fiber tip degradation, thus providing motivation for use of detachable and disposable distal fiber tips during lithotripsy. The 1-mm outer-diameter prototype also functioned comparable to previously tested tapered fiber tips. PMID:23455966

  14. Engineering Better Lithotripters.

    PubMed

    Chaussy, Christian G; Tiselius, Hans-Gran

    2015-08-01

    Although shock wave lithotripsy (SWL) remains an excellent non-invasive method for active removal of stones from the ureter and kidney, its popularity has decreased during recent years and the arguments for choosing endoscopic procedures rather than the only non-invasive surgical procedure are usually based on the opinion that SWL results are inferior to those obtained with endoscopic methods. It is considered that slow technical progress has not sufficiently met the requirements of disintegration, reduced need of repeated treatments, shorter treatment duration and less negative effects on tissues. This article summarises some recently published articles that address these problems and have the aim of improving the function of lithotripters. Modification of the shock wave geometry, elimination or control of cavitation bubbles, and different techniques of disintegration studied in in vitro and in animal experiments suggest several possible future directions that might provide a basis for development of a new "gold standard" lithotripter. PMID:26077353

  15. Variation of slow-wave frequency and locking during the migrating myoelectric complex in dogs.

    PubMed

    Caenepeel, P; Janssens, W; Accarino, A; Janssens, J; Vantrappen, G; Eyssen, H

    1991-12-01

    Slow waves determine rhythm and polarity of spike bursts. We measured the variation of slow-wave frequency (swf) and locking (swl) in the canine jejunum during the various phases of the migrating myoelectric complex (MMC) and during induced phase III (erythromycin 125 micrograms/kg iv bolus or somatostatin 2.5 micrograms.kg-1.h-1 iv infusion), blocked phase III (atropine 20 micrograms/kg iv bolus), and so-called stationary phase III activity (cisapride 150 micrograms/kg iv bolus). The EMG of 4 dogs, implanted with 10 bipolar electrodes, was recorded on a polygraph. Our results indicate that swf and swl change during the MMC from a stepwise swf gradient with slow waves locked in plateaus during phase I to a continuous swf gradient without or with significantly reduced phase locking during phase III. The length of the first swf plateau decreases significantly from 42 +/- 12 cm post Treitz during phase I to 11 +/- 4 cm during spontaneous phase III. Atropine block of phase III activity prevents phase unlocking and development of a continuous swf gradient. Our hypothesis is that phase unlocking may be one of the induction mechanisms of spike-burst activity. PMID:1685071

  16. The Evaluation of Ureteroscopy and Pneumatic Lithotripsy Results in Pregnant Women With Urethral Calculi

    PubMed Central

    Keshvari Shirvan, Maliheh; Darabi Mahboub, Mohammad Reza; Rahimi, Hamid Reza; Seyedi, Ali

    2013-01-01

    Background Urinary stone incidence in pregnancy has been reported in a wide range, from 1 in 200 to 1 in 2000 cases. Objectives The aim of this study was to investigate the efficacy and safety of ureteroscopic treatment and its results and complications for pregnant women with urinary stones. Patients and Methods From 2003 till 2011, 113 pregnant patients with symptomatic urolithiasis were admitted to the urology emergency clinic at Imam Reza hospital. All patients were initially treated conservatively, resulting in spontaneous passage of the calculi in 69 patients. Forty-four patients with symptomatic urolithiasis were included in the study. Post-operative follow ups, including maternal and fetal health was performed by a gynecologist consult fetal heart rate assessment and urine analysis and culture and renal and urethral ultrasonography. Results The mean age of the patients was 23 years ± 2 (19-34) and the mean gestational age was 24 ± 3 weeks. The overall and pneumatic lithotripsy success rate was 100%. All patients from the interventional group delivered at term with no fetal or maternal complications. There was no morbidity during and after the operation. Conclusions In conditions, medical management of urinary stones and consequent renal colic in pregnant women cannot improve patients’ symptoms, choosing of a surgical method like setting of a DJ catheter or URS and pneumatic lithotripsy can be a safe and effective way for the health of both the mother and fetus. Of course, more research is needed to establish this approach as the standard method in pregnancy urinary stones. PMID:24350085

  17. A comparison of efficacies of holmium YAG laser, and pneumatic lithotripsy in the endoscopic treatment of ureteral stones

    PubMed Central

    Akdeniz, Ekrem; İrkılata, Lokman; Demirel, Hüseyin Cihan; Saylık, Acun; Bolat, Mustafa Suat; Şahinkaya, Necmettin; Zengin, Mehmet; Atilla, Mustafa Kemal

    2014-01-01

    Objective: We aimed to compare the effectiveness of holmium YAG laser and pneumatic lithotripsy in the treatment of ureteral stones. Material and methods: A total of 216 patients who had established indications of ureteroscopy between November 2011 and June 2012 were included in this study. Patients’ files were retrospectively reviewed by dividing cases as groups that underwent pneumatic (PL) or laser lithotripsy (LL) procedures. Age, sex, stone burden and localization, duration of follow-up, operative times were evaluated. Stone-free rates were evaluated by ureteroscopical examination, postoperative scout films and ultrasonography. Results: Group PL consisted of 109 and group LL of 107 patients. Median age was 43.93±15.94 years in Group PL and 46.15±14.54 years in Group LL. Male to female ratio, stone burden and localization were similar for both groups. Overall success rate was 89.9% in Group PL and 87.9% in Group LL, respectively (p<0.791). With the aid of additional procedures, success rate was 100% for both groups at the end of the first month. Groups were not different as for operative time, rate of insertion of an ureteral catheter and its removal time. Hospitalization period was apparently somewhat shorter in Group LL (p=0.00). Conclusion: Pneumatic lithotripsy can be as efficacious as laser lithotripsy and be used safely in the endoscopic management of ureteral stone. In comparison of both methods, we detected no differences as to operative time, success of operation and the time to removal of the catheter, however, hospitalization period was shorter in Group LL. PMID:26328167

  18. The evolution of the endourologic management of pediatric stone disease

    PubMed Central

    Smaldone, Marc C.; Gayed, Bishoy A.; Ost, Michael C.

    2009-01-01

    In the 1980s, the advent of shock wave lithotripsy (SWL) revolutionized pediatric stone management and is currently the procedure of choice in treating most upper tract calculi <1.5 cm in children. However, with miniaturization of instruments and refinement of surgical technique the management of pediatric stone disease has undergone a dramatic evolution over the past twenty years. In a growing number of centers, ureteroscopy (URS) is now being performed in cases that previously would have been treated with SWL or percutaneous nephrolithotomy (PCNL). PCNL has replaced open surgical techniques for the treatment of large stone burdens >2 cm with efficacy and complication rates similar to the adult population. Recent results of retrospective reviews of large single institution series demonstrate stone free and complication rates with URS comparable to PCNL and SWL but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burden are needed to reach consensus regarding the most effective primary treatment modality in children. This report provides a comprehensive review of the literature evaluating the indications, techniques, complications, and efficacy of endourologic stone management in children. PMID:19881120

  19. Bilateral stones as a cause of acute renal failure in the emergency department

    PubMed Central

    Alonso, Joaquín V.; cachinero, Pedro L.; Ubeda, Fran R.; Ruiz, Daniel J. L.; Blanco, Alfredo

    2014-01-01

    BACKGROUND: Acute renal failure (ARF) due to obstructive uropathy is a urological emergency. The standard radiological investigations in the emergency setting include X-ray, ultrasonography and computed tomography. But occasionally the cause of obstruction may be elusive. METHODS: We present a case of obstructive uropathy due to bilateral stones presenting as acute renal failure. The patient underwent successful shock wave lithotripsy (SWL) for dissolution of calculi. RESULTS: The patient was successfully treated, and reported asymptomatic in a follow-up. CONCLUSION: Close collaboration between nephrological, urological, and radiological services is required. PMID:25215151

  20. Moderate high power 1 to 20μs and kHz Ho:YAG thin disk laser pulses for laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Renz, Günther

    2015-02-01

    An acousto-optically or self-oscillation pulsed thin disk Ho:YAG laser system at 2.1 μm with an average power in the 10 W range will be presented for laser lithotripsy. In the case of cw operation the thin disk Ho:YAG is either pumped with InP diode stacks or with a thulium fiber laser which leads to a laser output power of 20 W at an optical-to-optical efficiency of 30%. For the gain switched mode of operation a modulated Tm-fiber laser is used to produce self-oscillation pulses. A favored pulse lengths for uric acid stone ablation is known to be at a few μs pulse duration which can be delivered by the thin disk laser technology. In the state of the art laser lithotripter, stone material is typically ablated with 250 to 750 μs pulses at 5 to 10 Hz and with pulse energies up to a few Joule. The ablation mechanism is performed in this case by vaporization into stone dust and fragmentation. With the thin disk laser technology, 1 to 20 μs-laser pulses with a repetition rate of a few kHz and with pulse energies in the mJ-range are available. The ablation mechanism is in this case due to a local heating of the stone material with a decomposition of the crystalline structure into calcium carbonate powder which can be handled by the human body. As a joint process to this thermal effect, imploding water vapor bubbles between the fiber end and the stone material produce sporadic shock waves which help clear out the stone dust and biological material.

  1. Generation of shear waves as an effective mechanism of dynamic load of the lithotripter shock wave on the kidney stone

    NASA Astrophysics Data System (ADS)

    Sapozhnikov, Oleg A.; Cleveland, Robin O.; Bailey, Michael R.; Crum, Lawrence A.

    2003-10-01

    A number of stone comminution mechanisms have been studied in lithotripsy. Except cavitation erosion, these mechanisms (namely, spallation, dynamic fatigue, shear, and circumferential compression) are associated with stresses generated in the stone by the shock wave. The mechanical load on the stone depends on the waveform and stone structure, size, and shape. We modeled the propagation of lithotripter shock waves through a cylindrical stone with a finite differences simulation based on Lame's equation. The stone parameters were similar to those of natural kidney stones. A new mechanism of tensile stress generation is predicted that may be 5-10 times more efficient than spalling. Shear elasticity of the stone gave rise to the peak tensile strain in the bulk of the stone; this strain occurs near the stone axis due to coherent arrival of shear waves from the front edges of the stone. The position of the region of maximum strain and direction of corresponding tensile forces is similar to those predicted by the spalling mechanism. The modeling also showed that circumferential compression is not activated by the dynamic load produced by a short shock wave typical for lithotripsy. [Work supported by NIH PO1 DK43881, RO1 DK55674 and FOGARTY, CDRF, ONRIFO, and NSBRI.

  2. Investigation on the impact of pulse duration for laser induced lithotripsy

    NASA Astrophysics Data System (ADS)

    Sroka, Ronald; Kiris, Tugba; Fiedler, Sebastian; Scheib, Gabriel; Kuznetsova, Julia; Pongratz, Thomas

    2014-03-01

    Objective: In-vitro investigation of Ho:YAG-laser induced stone fragmentation was performed to identify potential impacts of different pulse durations on stone fragmentation characteristics. Materials and Methods: An innovative Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long- or short pulse mode was tested with regard to its fragmentation properties. The pulse duration depends on the specific laser parameter used. Fragmentation tests (hand held, hands free, single pulse induced crater) on artificial BEGO-Stones and fiber burn back tests were performed under reproducible experimental conditions. Additionally, the repulsion of long versus short laser pulses was compared using the pendulum set-up. Results: Differences in fragmentation rates between the two pulse duration regimes were seen. The difference was, however, not statistically significant. Using long pulse mode, the fiber burn back is nearly negligible while in short pulse mode an increased burn back was seen. The results of the pendulum test showed that the deviation induced by the momentum of shorter pulses is increased compared to longer pulses. Conclusion: Long pulse-mode showed reduced side effects like repulsion and fiber burn back in comparison to short pulse-mode while fragmentation rates remained at a comparable level. Lower push back and reduced burn back of longer laser pulses may results in better clinical outcome of laser lithotripsy and more convenient handling during clinical use.

  3. Shock-induced bubble collapse in a vessel: Implications for vascular injury in shockwave lithotripsy

    NASA Astrophysics Data System (ADS)

    Coralic, Vedran; Colonius, Tim

    2014-11-01

    In shockwave lithotripsy, shocks are repeatedly focused on kidney stones so to break them. The process leads to cavitation in tissue, which leads to hemorrhage. We hypothesize that shock-induced collapse (SIC) of preexisting bubbles is a potential mechanism for vascular injury. We study it numerically with an idealized problem consisting of the three-dimensional SIC of an air bubble immersed in a cylindrical water column embedded in gelatin. The gelatin is a tissue simulant and can be treated as a fluid due to fast time scales and small spatial scales of collapse. We thus model the problem as a compressible multicomponent flow and simulate it with a shock- and interface-capturing numerical method. The method is high-order, conservative and non-oscillatory. Fifth-order WENO is used for spatial reconstruction and an HLLC Riemann solver upwinds the fluxes. A third-order TVD-RK scheme evolves the solution. We evaluate the potential for injury in SIC for a range of pressures, bubble and vessel sizes, and tissue properties. We assess the potential for injury by comparing the finite strains in tissue, obtained by particle tracking, to ultimate strains from experiments. We conclude that SIC may contribute to vascular rupture and discuss the smallest bubble sizes needed for injury. This research was supported by NIH Grant No. 2PO1DK043881 and utilized XSEDE, which is supported by NSF Grant No. OCI-1053575.

  4. Extracorporeal shockwave lithotripsy vs. percutaneous nephrolithotomy vs. flexible ureterorenoscopy for lower-pole stones

    PubMed Central

    Knoll, Thomas; Buchholz, Noor; Wendt-Nordahl, Gunnar

    2012-01-01

    Objectives To review previous reports and discuss current trends in extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureterorenoscopy (URS). ESWL was recommended as the first-line treatment for small and intermediate-sized stones in the lower pole, while it is the standard treatment for large stones. However, the stone clearance rate after ESWL seems to be lower than that of stones in other locations. This seems to result from a lower rate of fragment passage, due to anatomical factors. Methods Reports on urinary stone disease were reviewed, assessing only publications in peer-reviewed, Medline-listed journals in the English language (publication years 1990–2011). Results Recent experience with flexible URS (fURS) for intrarenal stones showed that excellent stone-free rates can be achieved. With increasing experience and technically improved equipment, fURS has become an alternative to ESWL for small and intermediate-sized renal stones. Furthermore, several authors reported successful retrograde treatment for large renal stones, proposing fURS as an alternative to PCNL. However, the major drawbacks are long operating times and commonly, staged procedures, which is why PCNL remains the method of choice for such stones. Conclusions Considering the currents trends and evidence, the 2012 update of the European Association of Urology Guidelines on Urolithiasis has upgraded the endourological treatment of kidney stones. Individual factors such as body habitus, renal anatomy, costs and patient preference must be considered. PMID:26558046

  5. Holmium Laser Lithotripsy with Semi-Rigid Ureteroscopy: A First-Choice Treatment for Impacted Ureteral Stones in Children?

    PubMed Central

    Adanur, Senol; Aydin, Hasan Riza; Ozkaya, Fatih; Ziypak, Tevfik; Polat, Ozkan

    2014-01-01

    Background We aimed to assess the effectiveness of semi-rigid ureteroscopy and holmium laser lithotripsy in the treatment of impacted ureteral stones in children. Material/Methods We evaluated a total of 32 children under the age of 18 years treated with ureteroscopic holmium laser lithotripsy for impacted ureteral stones between January 2005 and July 2013. Their stone-free state was defined as the absence of any residual stone on radiologic evaluation performed 4 weeks postoperatively. Complications were evaluated according to the modified Clavien classification. Result The mean patient age was 9.5±5.1 years (range 1–18 years). Seven (21.8%) of the stones were located in the proximal ureter, 9 (28.2%) were in the mid-ureter, and 16 (50%) were in the distal ureter. The mean stone size was calculated as being 10.46±3.8 mm2 (range 5–20). The stone-free rate was 93.75% (30/32 patients) following primary URS. Additional treatment was required for only 2 (6.25%) of the patients. After the procedure, a D-J stent was placed in all the patients. The total complication rate was 15.6% (5 patients). The 10 total complications in these 5 patients were 5 (15.6%) Grade I, 1 (3.1%) Grade II, 2 (6.25%) Grade IIIa, and 2 (6.25%) Grade IIIb. The mean follow-up period was 16.5 months (range 3–55). Conclusions For the treatment of impacted ureteral stones in children, holmium laser lithotripsy with semi-rigid ureteroscopy, with its low retreatment requirement and acceptable complication rates, is an effective and reliable method in experienced and skilled hands as a first-choice treatment approach. PMID:25415256

  6. Efficacy and safety of Ho:YAG Laser Lithotripsy for ureteroscopic removal of proximal and distal ureteral calculi

    PubMed Central

    2014-01-01

    Background Laser lithotripsy is an established endourological modality. Ho:YAG laser have broadened the indications for ureteroscopic stone managements to include larger stone sizes throughout the whole upper urinary tract. Aim of current work is to assess efficacy and safety of Ho:YAG laser lithotripsy during retrograde ureteroscopic management of ureteral calculi in different locations. Methods 88 patients were treated with ureteroscopic Ho:YAG laser lithotripsy in our institute. Study endpoint was the number of treatments until the patient was stone-free. Patients were classified according to the location of their stones as Group I (distal ureteric stones, 51 patients) and group II (proximal ureteral stones, 37). Group I patients have larger stones as Group II (10.70 mm vs. 8.24 mm, respectively, P = 0.020). Results Overall stone free rate for both groups was 95.8%. The mean number of procedures for proximal calculi was 1.1 ± 0.1 (1–3) and for distal calculi was 1.0 ± 0.0. The initial treatment was more successful in patients with distal ureteral calculi (100% vs. 82.40%, respectively, P = 0.008). No significant difference in the stone free rate was noticed after the second laser procedure for stones smaller versus larger than 10 mm (100% versus 94.1%, P = 0.13). Overall complication rate was 7.9% (Clavien II und IIIb). Overall and grade-adjusted complication rates were not dependant on the stone location. No laser induced complications were noticed. Conclusions The use of the Ho:YAG laser appears to be an adequate tool to disintegrate ureteral calculi independent of primary location. Combination of the semirigid and flexible ureteroscopes as well as the appropriate endourologic tools could likely improve the stone clearance rates for proximal calculi regardless of stone-size. PMID:25107528

  7. Differentiation of tissue and kidney stones for laser lithotripsy using different spectroscopic approaches

    NASA Astrophysics Data System (ADS)

    Lange, Birgit; Cordes, Jens; Brinkmann, Ralf

    2015-07-01

    Holmium lasers are nowadays the gold standard for endoscopic laser lithotripsy. However, there is a risk of damaging or perforating the ureter or kidney tissue when the vision is poor. An automatic tissue/stone differentiation would improve the handling and safety of the procedure. To achieve this objective, an easy and robust real-time discrimination method has to be found which can be used to realize a feedback loop to control the laser system. Two possible approaches have been evaluated: White light reflectance and fluorescence spectroscopy. In both cases, we use the treatment fiber for detection and evaluate the possibility to decide whether the fiber is placed in front of tissue or calculus by the signal that is delivered by the surface in front of it. White light reflectance spectroscopy uses the standard light source for endourologic surgeries: Radiation of a Xenon light source is coupled to the ureteroscope via a liquid light guide. The part of the white light that is reflected back into the fiber is spectroscopically analyzed. In a clinical proof of concept study reflection signals were measured in vivo in 8 patients. For differentiation of stone and tissue via autofluorescence, excitation as well as detection was done via the treatment fiber. A suitable excitation wavelength was chosen with in vitro measurements (UV / visible) on several human renal calculi and porcine tissues. For verification of the positive results with green excitation in a clinical proof of concept study, a measurement set-up was realized which allows the recording of fluorescence signals during an endourological intervention.

  8. Percutaneous Transhepatic Endoscopic Holmium Laser Lithotripsy for Intrahepatic and Choledochal Biliary Stones

    SciTech Connect

    Rimon, Uri; Kleinmann, Nir; Bensaid, Paul; Golan, Gil; Garniek, Alexander; Khaitovich, Boris; Winkler, Harry

    2011-12-15

    Purpose: To report our approach for treating complicated biliary calculi by percutaneous transhepatic endoscopic biliary holmium laser lithotripsy (PTBL). Patients and Methods: Twenty-two symptomatic patients (11 men and 11 women, age range 51 to 88 years) with intrahepatic or common bile duct calculi underwent PTBL. Nine patients had undergone previous gastrectomy and small-bowel anastomosis, thus precluding endoscopic retrograde cholangiopancreatography. In the other 13 patients, stone removal attempts by ERCP failed due to failed access or very large calculi. We used a 7.5F flexible ureteroscope and a 200-{mu}m holmium laser fiber by way of a percutaneous transhepatic tract, with graded fluoroscopy, to fragment the calculi with direct vision. Balloon dilatation was added when a stricture was seen. The procedure was performed with the patient under general anaesthesia. A biliary drainage tube was left at the end of the procedure. Results: All stones were completely fragmented and flushed into the small bowel under direct vision except for one patient in whom the procedure was aborted. In 18 patients, 1 session sufficed, and in 3 patients, 2 sessions were needed. In 7 patients, balloon dilatation was performed for benign stricture after Whipple operation (n = 3), for choledochalenteric anastomosis (n = 3), and for recurrent cholangitis (n = 1). Adjunctive 'balloon push' (n = 4) and 'rendezvous' (n = 1) procedures were needed to completely clean the biliary tree. None of these patients needed surgery. Conclusion: Complicated or large biliary calculi can be treated successfully using PTBL. We suggest that this approach should become the first choice of treatment before laparoscopic or open surgery is considered.

  9. Comparison Between Percutaneous Transhepatic Rigid Cholangioscopic Lithotripsy and Conventional Percutaneous Transhepatic Cholangioscopic Surgery for Hepatolithiasis Treatment

    PubMed Central

    Sun, Beiwang; Huang, Binyuan; Xie, Jiafen; Liu, Yanmin; Zhu, Canhua; Ye, Chen; Zhou, Zixuan

    2016-01-01

    Background: Percutaneous transhepatic cholangioscopy (PTCS) is one option for treating hepatolithiasis without surgical resection. This approach can use conventional biliary drainage methods over a long period, but a shorter procedure needs to be evolved. Objective: To evaluate the short-term and the long-term therapeutic outcomes of percutaneous transhepatic cholangioscopic lithotripsy (PTCSL) in comparison with conventional PTCS. Methods: In this retrospective study, 118 patients with hepatolithiasis were enrolled who underwent treatment in our hospital between March 2007 and July 2014. About 67 of them received PTCSL and the remaining 51 patients received conventional PTCS. Preoperative data, surgical operation-related records, the postoperative therapeutic effect, and the long-term hepatolithiasis recurrence rate were collected for comparison between the 2 groups. Results: The age, sex, and surgical history were similar between the 2 groups, but there was a significant difference in the Child-Pugh score, with more grade 3 patients in the PTCS group (P=0.002). However, the operation time, intraoperative blood infusion, and the blood loss were similar between the 2 groups. The final clearance ratio of calculus in the PTCSL group was significantly better than in the PTCS group after multivariate analysis (P=0.021; OR=0.201; 95% CI, 0.051-0.785). Calculus recurrence was 9% (PTCSL) and 22% (PTCS). The postoperative hospital stay was significantly shorter in the PTCSL group (P=0.001; OR=1.337; 95% CI, 1.132-1.58). Conclusions: PTCSL was a satisfactory therapeutic option for hepatolithiasis treatment, with less operation time and a superior long-term therapeutic effect compared with conventional PTCS. PMID:26679679

  10. Computed tomography-based novel prediction model for the stone-free rate of ureteroscopic lithotripsy.

    PubMed

    Kim, Jong Wook; Chae, Ji Yun; Kim, Jin Wook; Oh, Mi Mi; Park, Hong Seok; Moon, Du Geon; Yoon, Cheol Yong

    2014-02-01

    The purpose of this study was to evaluate whether computed tomography (CT) parameters can predict the success of ureteroscopic lithotripsy (URSL) and establish a model for predicting the success rates of a single URSL procedure for the treatment of a single ureteral stone. We retrospectively reviewed the records of 237 patients who underwent URSL for ureteral stones diagnosed by CT between January 2009 and June 2012. Stone-free status was defined as the absence of stones or residual stone fragments <2 mm by ureteroscopy and plain abdominal radiography. We analyzed the correlations between the outcome of URSL and the patients' sex, age, height, body weight, body mass index, and history of ureteral stone. Stone factors such as the diameter (D), stone height (H), volumetric stone burden (VSB; D(2) × H × 5 mm × π × 1/6), estimated stone location (ESL; number of axial cut images between the stone and uretero-vesical junction), tissue rim sign (RS; 0-3), perinephric edema (0-3), hydronephrosis (0-3), and Hounsfield unit (HU) were also analyzed. We then developed a model to predict the probability of successful URSL by applying a logistic model to our data. The success rate of URSL was 85.7% (203/237). Univariate analysis found that stone diameter, length, VSB, ESL, HU and RS significantly affected the stone-free rate. Multivariate analysis indicated that stone diameter, ESL and RS independently influenced the stone-free rate. The logistic model indicated that success rates = 1/[1 + exp{-6.146 + 0.071(D) + 0.153(ESL) + 1.534(RS)}] with an area under the receiver operating characteristic curve of 0.825. Stone diameter, ESL, and RS were independent predictors of the outcome of a single URSL for a single ureteral stone. PMID:24162952

  11. Treatment of ureteral calculus obstruction with laser lithotripsy in an Atlantic bottlenose dolphin (Tursiops truncatus).

    PubMed

    Schmitt, Todd L; Sur, Roger L

    2012-03-01

    An adult female bottlenose dolphin (Tursiops truncatus) presented with acute anorexia secondary to progressive azotemia (blood urea nitrogen = 213 mg/dl, creatinine [Cr] = 9.5 mg/dl) and electrolyte abnormalities (K = 7.4 mEq/L). It was later diagnosed with postrenal obstruction secondary to bilaterally obstructing ureteral calculi seen on ultrasound. Treatment of the obstruction required two endoscopic procedures, cystoscopy for ureteral stent placement and ureteroscopy to perform intracorporeal lithotripsy on the obstructing calculi. Before the first procedure, the dolphin's azotemia was stabilized with aggressive fluid therapy, peritoneal dialysis, and treatment for acidosis. Diuresis subsequent to the fluid therapy enabled passage of the right obstructing urolith. For both endoscopic procedures, the dolphin was placed in left lateral recumbency due to the peritoneal dialysis catheter in the right retroperitoneal region. For the first procedure, a 12-French (Fr) flexible cystoscope was inserted retrograde into the bladder via the urethra, whereupon a calculus was seen obstructing the left ureteral orifice. A 4.8-Fr, 26-cm double-pigtail ureteral stent was placed up the left ureter to relieve the postrenal obstruction. Inadvertent proximal migration of the left ureteral stent occurred during the procedure. However, renal parameters (serum Cr = 5.8, K = 5.4) improved significantly by the next day. For the second procedure, 28 hr later, ureteroscopy was performed to treat the calculus and replace the existing stent with a longer stent. The left ureteral calculus was pulverized into tiny fragments by using a holmium:yttrium-aluminum-garnet laser inserted through a 6.9-Fr semirigid ureteroscope. The migrated stent was visualized in the distal left ureter and replaced with a 90-cm single-pigtail ureteral stent that was sutured exterior to the urogenital slit and removed 3 days later. Renal function normalized over the next several days, and the dolphin recovered over the next 2 mo. PMID:22448516

  12. Extracorporeal shockwave lithotripsy for lower pole calculi smaller than one centimeter

    PubMed Central

    Chaussy, Christian; Bergsdorf, Thorsten

    2008-01-01

    Extracorporeal shockwave lithotripsy (ESWL) has revolutionized the treatment of urinary calculi and became the accepted standard therapy for the majority of stone patients. Only for stones located in the lower calix, ESWL displayed a limited efficacy. Since the stone-free rate seemed to be preferential, endoscopic maneuvers like percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) have been proposed as the primary approach for this stone localization. Stone size seems to be the most important parameter in regard to the stone-free rate, whereas anatomical characteristics of the lower pole collecting system are discussed controversial. Various studies show a good stone clearance between 70-84% for stones up to 1 cm in diameter. Additional physical and medical measures are suitable to improve treatment results. Stone remnants after ESWL, defined as clinical insignificant residual fragments (CIRF) will not cause problems in every case and will pass until up to 24 months after treatment; in total 80-90% of all patients will become stone-free or at least symptom-free. When complete stone-free status is the primary goal, follow-up examinations with new radiological technologies like spiral CT show that the stone-free rate of ESWL and endoscopically treated patients (RIRS) does not differ significantly. However, in comparison to endoscopic stone removal, shockwave therapy is noninvasive, anesthesia-free and can be performed in an outpatient setup. Therefore, ESWL remains the first choice option for the treatment of lower caliceal stones up to 1 cm. The patient will definitely favour this procedure. PMID:19468510

  13. Solifenacin improves double-J stent-related symptoms in both genders following uncomplicated ureteroscopic lithotripsy.

    PubMed

    Lee, Yuan-Ju; Huang, Kuo-How; Yang, Hung-Ju; Chang, Hong-Chiang; Chen, Jun; Yang, Teng-Kai

    2013-06-01

    The objective of this study is to evaluate the effects of solifenacin on double-J stent-related symptoms following uncomplicated ureterosocpic lithotripsy (URSL). A total of 70 patients who underwent double-J ureteral stent insertion following URSL were consecutively recruited and received solifenacin postoperatively. Another 70 age- and sex-matched subjects without solifenacin therapy were enrolled as a control group. The clinical data including stone and stent characteristics were collected. All subjects completed the brief-form Ureteral Symptom Score Questionnaire (Chinese-version) to assess the lower urinary tract symptoms, stent-related body pain and hematuria 2 weeks after operation. The severity of stent-related symptoms was compared between two groups. The mean age was 53.8 in solifenacin group and 53.4 years in the control group (p = 0.87). The stone characteristics, stent size, position and curl completeness were similar in both groups. Compared to the control group, solifenacin group had significantly lower total symptom score, urgency and urge incontinence scores. As for stent-related body pain, solifenacin group had significantly less flank, abdominal, urethral pain and hematuria scores (all p < 0.05). The solifenacin versus control group showed significant benefits in lower urinary tract symptoms, stent-related pain and hematuria in both genders (all p < 0.05). Four subjects encountered minor adverse events (5.7 %) and one had urinary retention (1.4 %) in solifenacin group. For patients undergoing URSL and double-J stent indwelling, postoperative solifenacin use was effective and well-tolerated for the treatment of lower urinary tract symptoms, stent-related body pain and hematuria irrespective of genders. PMID:23515684

  14. Gall stone pulverisation strategy in patients treated with extracorporeal lithotripsy and follow up results of maintenance treatment with ursodeoxycholic acid.

    PubMed Central

    Boscaini, M; Piccinni-Leopardi, M; Andreotti, F; Montori, A

    1994-01-01

    Between November 1988 and July 1992 70 patients with radiolucent gall stones were treated with extracorporeal lithotripsy (ESL) and ursodeoxycholic acid (UDCA; mean (SD) dose 11.2 (1.9) mg/kg/day). Fifty three patients have been followed for one year. One week after lithotripsy, 30.6% had completely eliminated all stone fragments from the gall bladder and one year later 93.9% were free of stones. Three factors were considered important in achieving these results. 'Pulverisation' of the stone--that is, its fragmentation into echogenic dust (crystalline aggregates, some few hundred mu in size) or particles similar to grains of sand, smaller than 1 mm in diameter, or both, is required. Secondly, dust and particles were rapidly eliminated, strongly suggesting a mechanical elimination process by physiological gall bladder contractions. Thirdly, there must be chemical dissolution with biliary acids. This therapeutic approach gave excellent results without causing any clinically relevant side effects. The first 20 patients who became free of stones after ESL were given oral bile acid maintenance treatment--300 mg/day of UDCA at bedtime, for two years. All were asymptomatic and none had suffered a recurrence after two years. In four patients, crystalline aggregates, detected in gall bladder bile by ultrasound, were subsequently dissolved between one and three months after resuming a full dose regimen of UDCA. Images Figure 2 Figure 3 PMID:8307431

  15. AB076. Compare the treatment of urolithiasis in a microchannel percutaneous nephrolithotomy pneumatic lithotripsy and open surgery

    PubMed Central

    Sun, Yuanxing

    2016-01-01

    Objective The aim of this study is to compare the treatment of urolithiasis in a microchannel percutaneous nephrolithotomy ultrasonic pneumatic lithotripsy and open stone surgery. Methods January 2014–October 2014 in our hospital treated 43 cases of patients with kidney stones as the observation group, the use of micro-channel percutaneous nephrolithotomy lithotripsy; and 48 cases of patients with urolithiasis in March 2013~December 2013 were treated as the control group, the use of open stone surgery treatment. Results It was observed in patients with clinical manifestations and complications during surgery, after statistical comparison of the results were analyzed. Observation group and control group operative time was no difference (P>0.05), hospitalization time in the observation group was shorter than the control group (P<0.05). Bleeding volume in the observation group was less than the control group (P<0.05). A clearance rate in the observation group was higher than the control group (P<0.05), the incidence of complications in the observation group was less than the control group (P<0.05). Conclusion The difference was statistically significant. Significant effect of microchannel percutaneous nephrolithotomy is smaller surgical trauma and shorter hospital stay.

  16. The mechanisms of stone disintegration by shock waves.

    PubMed

    Sass, W; Bräunlich, M; Dreyer, H P; Matura, E; Folberth, W; Preismeyer, H G; Seifert, J

    1991-01-01

    Through interpretation of high-speed films at 10,000 frames per second of shock wave action on kidney stones and gallstones, the mechanism of stone destruction was analyzed in detail. This shows that the interaction of the shock wave with the targets firstly produces fissures in the stone material. Liquid then enters these small cracks. The actual disintegration is caused later by the enormous violence of imploding cavitation bubbles within these small split lines. That cavitation acts inside the stone and causes fragmentation even within the human gallbladder could furthermore be demonstrated by using scanning electron microscopy. These results should lead to a different process in gallstone lithotripsy leaving intervals between the shock wave treatments. This will allow the viscous bile fluids to occupy the fissures of the stones more completely and, therefore, should increase the cavitational activity on the subsequent treatment with shock pulses. PMID:1887509

  17. Air bubble-shock wave interaction adjacent to gelantine surface

    NASA Astrophysics Data System (ADS)

    Lush, P. A.; Tomita, Y.; Onodera, O.; Takayama, K.; Sanada, N.; Kuwahara, M.; Ioritani, N.; Kitayama, O.

    1990-07-01

    The interaction between a shock wave and an air bubble-adjacent to a gelatine surface is investigated in order to simulate human tissue damage resulting from extracorporeal shock wave lithotripsy. Using high speed cine photography it is found that a shock wave of strength 11 MPa causes 1-3 mm diameter bubbles to produce high velocity microjets with penetration rates of approximately 110 m/s and penetration depths approximately equal to twice the initial bubble diameter. Theoretical considerations for liquid impact on soft solid of similar density indicate that microjet velocities will be twice the penetration rate, i.e. 220 m/s in the present case. Such events are the probable cause of observed renal tissue damage.

  18. [The 24 May, 2009 isolation of the first A/IIV-Moscow/01/2009 (H1N1)swl strain similar to swine A(H1N1) influenza virus from the first Moscow case detected on May 21, 2009, and its deposit in the state collection of viruses (SCV No. 2452 dated May 24, 2009)].

    PubMed

    L'vov, D K; Burtseva, E I; Prilipov, A G; Bazarova, M V; Kolobukhina, L V; Merkulova, L N; Malyshev, N A; Deriabin, P G; Fediakina, I T; Sadykova, G K; Usachev, E V; Shchelkanov, M Iu; Shevchenko, E S; Trushakova, S V; Ivanova, V T; Beliakova, N V; Oskerko, T A; Aliper, T I

    2009-01-01

    The paper presents the results of the first isolation of the new influenza virus in Moscow and the Russian Federation, which was similar to the swine A/IIV-Moscow/01/2009(H1N1)swl strain isolated on May 24, 2009 from a Russian arrived in Moscow from the USA on May 19, 2009. The antigenic, biological, and molecular genetic properties of this virus were studied. The virus was isolated on MDCK and chick embryos, the hemagglutination titers being 1:8-1:16 AE; the infectious titers being 6.51g of the tissue cytopathogenic infective dose (TCID50) and 7.01g of the common infective dose (CID50). The virus was sensitive to arbidol, ribavirin, oseltamivir, and resistant to rimantadine. The complete virus genome was sequenced; the data were accepted to the Gen Bank on May 28, 2009 under GQ219584-GQ219590 and GQ202724. The significant gene substitution of neuraminidase Asp for Gly in position 451, which has been undetectable in any other strain published in the Gen Bank by the present time is unique only to A/IIV-Moscow/01/2009 (H1N1)swl. The virus has been deposited in the State Collection of Viruses, D. I. Ivanovsky Institute of Virology, Russian Academy of Medical Sciences, under No. 2452 dated May 24, 2009. PMID:19882896

  19. Suppression of shocked-bubble expansion due to tissue confinement with application to shock-wave lithotripsy

    PubMed Central

    Freund, Jonathan B.

    2008-01-01

    Estimates are made of the effect of tissue confinement on the response of small bubbles subjected to lithotriptor shock pressures. To do this the Rayleigh–Plesset equation, which governs the dynamics of spherical bubbles, is generalized to treat a bubble in a liquid region (blood), which is in turn encased within an elastic membrane (like a vessel’s basement membrane), beyond which a Voigt viscoelastic material models the exterior tissue. Material properties are estimated from a range of measurements available for kidneys and similar soft tissues. Special attention is given to the constitutive modeling of the basement membranes because of their expected importance due to their proximity to the bubble and their toughness. It is found that the highest expected values for the elasticity of the membrane and surrounding tissue are insufficient to suppress bubble growth. The reduced confinement of a cylindrical vessel should not alter this conclusion. Tissue viscosities taken from ultrasound measurements suppress bubble growth somewhat, though not to a degree expected to resist injury. However, the higher reported viscosities measured by other means, which are arguably more relevant to the deformations caused by growing bubbles, do indeed significantly suppress bubble expansion. PMID:18529202

  20. Sudden onset of a huge subcapsular renal hematoma following minimally invasive ureteroscopic holmium laser lithotripsy: A case report

    PubMed Central

    ZHANG, PENG; HU, WAN-LI

    2015-01-01

    The postoperative complication rate of ureteroscopic lithotripsy (URSL) is low, and the most frequent complication is fever. Thus, urological surgeons often neglect or are unaware of subcapsular renal hematoma (SRH) as a rare complication following URSL. Although a SRH after undergoing URSL is uncommon, the occurrence may be fatal. The current study reports on a rare life-threatening case that occurred recently at Zhongnan Hospital (Wuhan, China). A 24-year-old male patient presented with a large SRH (111411 cm) after undergoing a failed, but minimally invasive URSL with a holmium laser. The presence of the large SRH was confirmed by computerized tomography imaging. The patient underwent conservative management, which prevented hematoma enlargement, and no further treatment was conducted. In conclusion, SRH, although rare following URSL, should be noted by the urological surgeon. PMID:26170958

  1. Characterization of calculus migration during Ho:YAG laser lithotripsy by high speed camera using suspended pendulum method

    NASA Astrophysics Data System (ADS)

    Zhang, Jian James; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Chia, Ray W. J.; Hasenberg, Tom

    2014-03-01

    Calculus migration is a common problem during ureteroscopic laser lithotripsy procedure to treat urolithiasis. A conventional experimental method to characterize calculus migration utilized a hosting container (e.g. a "V" grove or a test tube). These methods, however, demonstrated large variation and poor detectability, possibly attributing to friction between the calculus and the container on which the calculus was situated. In this study, calculus migration was investigated using a pendulum model suspended under water to eliminate the aforementioned friction. A high speed camera was used to study the movement of the calculus which covered zero order (displacement), 1st order (speed) and 2nd order (acceleration). A commercialized, pulsed Ho:YAG laser at 2.1 um, 365-um core fiber, and calculus phantom (Plaster of Paris, 10×10×10mm cube) were utilized to mimic laser lithotripsy procedure. The phantom was hung on a stainless steel bar and irradiated by the laser at 0.5, 1.0 and 1.5J energy per pulse at 10Hz for 1 second (i.e., 5, 10, and 15W). Movement of the phantom was recorded by a high-speed camera with a frame rate of 10,000 FPS. Maximum displacement was 1.25+/-0.10, 3.01+/-0.52, and 4.37+/-0.58 mm for 0.5, 1, and 1.5J energy per pulse, respectively. Using the same laser power, the conventional method showed <0.5 mm total displacement. When reducing the phantom size to 5×5×5mm (1/8 in volume), the displacement was very inconsistent. The results suggested that using the pendulum model to eliminate the friction improved sensitivity and repeatability of the experiment. Detailed investigation on calculus movement and other causes of experimental variation will be conducted as a future study.

  2. Clinical effectiveness of the PolyScope™ endoscope system combined with holmium laser lithotripsy in the treatment of upper urinary calculi with a diameter of less than 2 cm

    PubMed Central

    GU, SI-PING; HUANG, YUN-TENG; YOU, ZHI-YUAN; ZHOU, XIAOMING; LU, YI-JIN; HE, CAO-HUI; QI, JUAN

    2013-01-01

    The aim of this study was to evaluate the clinical value of the PolyScope™ endoscope system in the treatment of upper urinary calculi with a diameter of <2 cm. A total of 86 patients hospitalized with upper urinary tract calculi were included. The patients were placed under general or spinal anesthesia and in a lithotomy position. Following the dilation of the ureter, a guide wire was inserted under the direct vision of an F8/9.8 rigid ureteroscope, and an F12/14 flexible ureteral access sheath was positioned along the guide wire. Holmium laser lithotripsy was subsequently performed, using an F8.0 ‘PolyScope’ modular flexible ureteroscope. Plain film of the kidney-ureter-bladder (KUB) was performed 1 day subsequent to the surgery, in order to determine the result of the lithotripsy and the position of the double-J stent which was inserted after after holmium laser lithotripsy. In addition, in certain patients, KUB radiography was performed 2–4 weeks subsequent to the surgery, and extracorporeal shockwave lithotripsy (ESWL) was performed if the diameter of the residual stones was >6 mm. Lithotripsy was successful in 77 patients and the duration of the surgery ranged between 25 and 80 min (mean duration, 42 min). Little bleeding was observed. Three patients presented with a slight fever following the surgery; however, no ureteral perforation, high fever or septicemia was observed among the patients following anti-inflammatory treatment. The stone-free rate (SFR) of the single-pass lithotripsy was 89.5% (77/86) and the SFR with ESWL was 96.5% (83/86). The study demonstrated that the F8 modular flexible ureteroscope was safe, convenient and effective for the lithotripsy of upper-tract calculi. PMID:24137232

  3. Development of a system of automatic gap-adjusted electrodes for shock wave generators

    NASA Astrophysics Data System (ADS)

    Manousakas, Ioannis; Liang, Shen-Min; Wan, Long-Ray; Wang, Chia-Hui

    2004-11-01

    In this study, a system of automatic gap-adjusted electrodes is developed for electrohydraulic shock wave generators that can be used both for extracorporeal shock wave lithotripsy (treatment of renal calculi) and for the extracorporeal shock wave therapy for musculo-skeletal disorders. This system is composed of three main components: (1) two electrodes and their bases; (2) servo motors and control software; (3) a high sensitivity CCD camera and image processing program. To verify system performance, in vitro fragmentation tests have been conducted using kidney stone phantoms. Results indicate that the efficiency of stone fragmentation using automatic gap adjustment can be increased up to 55.2%, which is twice more than without automatic gap adjustment (26.7%). This system can be applied to any commercial electrohydraulic extracorporeal shock wave lithotriptor or orthotriptor without difficulty.

  4. Cost-effectiveness v patient preference in the choice of treatment for distal ureteral calculi: a literature-based decision analysis.

    PubMed

    Wolf, J S; Carroll, P R; Stoller, M L

    1995-06-01

    Ureteroscopy (URS) and extracorporeal shockwave lithotripsy (SWL) battle for supremacy in the management distal ureteral calculi. In order to clarify issues surrounding this controversy, we created a decision tree modeling URS or SWL with literature-based probabilities and used as endpoints both cost and patient preferences. Ureteroscopy was more successful than single-session or multiple-session SWL, 92.1% v 74.3% or 84.5%, and had a lower retreatment/complication rate. Although initial SWL was only slightly more expensive than URS, $4,420 v $4,337, the difference increased when the additional costs of complications and retreatment were calculated, $6,745 v $5,555. Using values for an "average" patient, SWL was preferred to URS in terms of patient satisfaction. The most important factors distinguishing between URS and SWL were the success of treatment, the cost of initial therapy, and patient attitudes toward unplanned ancillary procedures and retreatment. Although no alteration of success rates and cost figures within reasonable ranges made URS less cost-effective than SWL, individual differences in patients' aversion for complications allowed URS to be preferred to SWL in some situations. Therefore, SWL is less cost-effective than URS and is not necessarily preferred by patients. The physician should be aware of the principal determinants of the choice between URS and SWL treatment of distal ureteral calculi. PMID:7550267

  5. A Miniaturized, 1.9F Integrated Optical Fiber and Stone Basket for Use in Thulium Fiber Laser Lithotripsy.

    PubMed

    Wilson, Christopher R; Hutchens, Thomas C; Hardy, Luke A; Irby, Pierce B; Fried, Nathaniel M

    2015-10-01

    The thulium fiber laser (TFL) is being explored as an alternative laser lithotripter to the standard holmium:yttrium-aluminum-garnet laser. The more uniform beam profile of the TFL enables higher power transmission through smaller fibers. In this study, a 100-μm core, 140-μm outer-diameter (OD) silica fiber with 5-mm length hollow steel tip was integrated with 1.3F (0.433-mm OD) nitinol wire basket to form a 1.9F (0.633-mm OD) device. TFL energy of 30 mJ, 500 μs pulse duration, and 500 Hz pulse rate was delivered to human uric acid stones, ex vivo. Stone ablation rates measured 1.5 ± 0.2 mg/s, comparable to 1.7 ± 0.3 mg/s using bare fiber tips separately with stone basket. With further development, this device may minimize stone retropulsion, allowing more efficient TFL lithotripsy at higher pulse rates. It may also provide increased flexibility, higher saline irrigation rates through the ureteroscope working channel, reduce fiber degradation compared with separate fiber and basket manipulation, and reduce laser-induced nitinol wire damage. PMID:26167738

  6. Shock wave as biological therapeutic tool: From mechanical stimulation to recovery and healing, through mechanotransduction.

    PubMed

    d'Agostino, M C; Craig, K; Tibalt, E; Respizzi, S

    2015-12-01

    Extracorporeal Shock Wave Therapy (ESWT) is a form of "mechanotherapy", that, from its original applications as urological lithotripsy, gained the field of musculo-skeletal diseases as Orthotripsy (mainly tendinopaties and bone regenerative disorders) and Regenerative Medicine as well. The mechanisms of action of Shock Waves (SW), when applied in non-urological indications, are not related to the direct mechanical effect, but to the different pathways of biological reactions, that derive from that acoustic stimulations, through "mechano-transduction". So, the "mechanical model" of urological lithotripsy has been substituted by a "biological model", also supported by current knowledge in "mechanobiology", the emerging multidisciplinary field of science that investigates how physical forces and changes in cell/tissue mechanics can influence the tissue development, physiology and diseases. Although some details are still under study, it is known that SW are able to relief pain, as well to positively regulate inflammation (probably as immunomodulator), to induce neoangiogenesis and stem cells activities, thus improving tissue regeneration and healing. ESWT can be nowadays considered an effective, safe, versatile, repeatable, noninvasive therapy for the treatment of many musculo-skeletal diseases, and for some pathological conditions where regenerative effects are desirable, especially when some other noninvasive/conservative therapies have failed. Moreover, based on the current knowledge in SW mechanobiology, it seems possible to foresee new interesting and promising applications in the fields of Regenerative Medicine, tissue engineering and cell therapies. PMID:26612525

  7. Kidney stone ablation times and peak saline temperatures during Holmium:YAG and Thulium fiber laser lithotripsy, in vitro, in a ureteral model

    NASA Astrophysics Data System (ADS)

    Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

    2015-02-01

    Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental Thulium fiber laser (TFL) was studied and compared to clinical gold standard Holmium:YAG laser. The Holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. TFL (λ = 1908 nm) was operated with 35 mJ, 500 μs, 150-500 Hz, and 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate / 40% calcium phosphate), of uniform mass and diameter (4-5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 ml/min and 13.7 ml/min for the TFL and Holmium laser, respectively. The temperature 3 mm from tube's center and 1 mm above mesh sieve was measured by a thermocouple and recorded during experiments. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. Holmium laser time measured 167 +/- 41 s (n = 12). TFL times measured 111 +/- 49 s, 39 +/- 11 s, and 23 +/- 4 s, for pulse rates of 150, 300, and 500 Hz (n = 12 each). Mean peak saline irrigation temperatures reached 24 +/- 1 °C for Holmium, and 33 +/- 3 °C, 33 +/- 7 °C, and 39 +/- 6 °C, for TFL at pulse rates of 150, 300, and 500 Hz. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and reduced stone retropulsion, and may provide a clinical alternative to the conventional Holmium laser for lithotripsy.

  8. Obtaining patient feedback in an outpatient lithotripsy service is facilitated by use of a touch-screen tablet (iPad™) survey.

    PubMed

    Turney, B W; Reynard, J M

    2014-08-01

    There is now a requirement for every doctor in the UK to obtain patient feedback for revalidation. This can be an onerous and time-consuming task. The objective of this study was to evaluate a novel electronic patient feedback method in an outpatient lithotripsy service setting. Between September 2013 and January 2014, 100 patients attending an outpatient lithotripsy service in Oxford were asked to complete a selection of pre-approved NHS questions about the service they had received. Questions were presented on a tablet device (iPad™) and answered using the touch screen. Departmental staff were unaware of the questions in the survey. Patients were asked to complete the survey by an independent research nurse. Questions were created online in a free-to-use web-based survey application and presented on the tablet device in a user-friendly format via an application. Data were uploaded via wifi™ to the online system. Data were viewed, automatically analysed and displayed graphically. The age range of the patients surveyed was 20-80 years of age. All 100 patients completed the survey without difficulty. All patients answered every question. Data could be automatically viewed, analysed and presented graphically. This method of collecting patient feedback proved to be rapid and efficient. The feedback highlighted a high patient satisfaction with the lithotripsy service. A touch screen tablet device is an efficient and effective method of collecting truly objective patient feedback. This method of patient feedback could be employed in other clinical environments to collect data for revalidation purposes. PMID:24747981

  9. Water content contribution in calculus phantom ablation during Q-switched Tm:YAG laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Zhang, Jian J.; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Wang, Hui; Chia, Ray W. J.; Hasenberg, Tom; Kang, Hyun Wook

    2015-12-01

    Q-switched (QS) Tm:YAG laser ablation mechanisms on urinary calculi are still unclear to researchers. Here, dependence of water content in calculus phantom on calculus ablation performance was investigated. White gypsum cement was used as a calculus phantom model. The calculus phantoms were ablated by a total 3-J laser pulse exposure (20 mJ, 100 Hz, 1.5 s) and contact mode with N=15 sample size. Ablation volume was obtained on average 0.079, 0.122, and 0.391 mm3 in dry calculus in air, wet calculus in air, and wet calculus in-water groups, respectively. There were three proposed ablation mechanisms that could explain the effect of water content in calculus phantom on calculus ablation performance, including shock wave due to laser pulse injection and bubble collapse, spallation, and microexplosion. Increased absorption coefficient of wet calculus can cause stronger spallation process compared with that caused by dry calculus; as a result, higher calculus ablation was observed in both wet calculus in air and wet calculus in water. The test result also indicates that the shock waves generated by short laser pulse under the in-water condition have great impact on the ablation volume by Tm:YAG QS laser.

  10. Water content contribution in calculus phantom ablation during Q-switched Tm:YAG laser lithotripsy.

    PubMed

    Zhang, Jian J; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Wang, Hui; Chia, Ray W J; Hasenberg, Tom; Kang, Hyun Wook

    2015-12-01

    Q-switched (QS) Tm:YAG laser ablation mechanisms on urinary calculi are still unclear to researchers. Here, dependence of water content in calculus phantom on calculus ablation performance was investigated. White gypsum cement was used as a calculus phantom model. The calculus phantoms were ablated by a total 3-J laser pulse exposure (20 mJ, 100 Hz, 1.5 s) and contact mode with N=15 sample size. Ablation volume was obtained on average 0.079, 0.122, and 0.391  mm3 in dry calculus in air, wet calculus in air, and wet calculus in-water groups, respectively. There were three proposed ablation mechanisms that could explain the effect of water content in calculus phantom on calculus ablation performance, including shock wave due to laser pulse injection and bubble collapse, spallation, and microexplosion. Increased absorption coefficient of wet calculus can cause stronger spallation process compared with that caused by dry calculus; as a result, higher calculus ablation was observed in both wet calculus in air and wet calculus in water. The test result also indicates that the shock waves generated by short laser pulse under the in-water condition have great impact on the ablation volume by Tm:YAG QS laser. PMID:26662067

  11. Comparison of holmium:YAG and thulium fiber laser lithotripsy: ablation thresholds, ablation rates, and retropulsion effects

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard L.; Irby, Pierce B.; Fried, Nathaniel M.

    2011-07-01

    The holmium:YAG (Ho:YAG) laser lithotriptor is capable of operating at high pulse energies, but efficient operation is limited to low pulse rates (~10 Hz) during lithotripsy. On the contrary, the thulium fiber laser (TFL) is limited to low pulse energies, but can operate efficiently at high pulse rates (up to 1000 Hz). This study compares stone ablation threshold, ablation rate, and retropulsion for the two different Ho:YAG and TFL operation modes. The TFL (λ = 1908 nm) was operated with pulse energies of 5 to 35 mJ, 500-μs pulse duration, and pulse rates of 10 to 400 Hz. The Ho:YAG laser (λ = 2120 nm) was operated with pulse energies of 30 to 550 mJ, 350-μs pulse duration, and a pulse rate of 10 Hz. Laser energy was delivered through 200- and 270-μm-core optical fibers in contact mode with human calcium oxalate monohydrate (COM) stones for ablation studies and plaster-of-Paris stone phantoms for retropulsion studies. The COM stone ablation threshold for Ho:YAG and TFL measured 82.6 and 20.8 J/cm2, respectively. Stone retropulsion with the Ho:YAG laser linearly increased with pulse energy. Retropulsion with TFL was minimal at pulse rates less than 150 Hz, then rapidly increased at higher pulse rates. For minimal stone retropulsion, Ho:YAG operation at pulse energies less than 175 mJ at 10 Hz and TFL operation at 35 mJ at 100 Hz is recommended, with both lasers producing comparable ablation rates. Further development of a TFL operating with both high pulse energies of 100 to 200 mJ and high pulse rates of 100 to 150 Hz may also provide an alternative to the Ho:YAG laser for higher ablation rates, when retropulsion is not a primary concern.

  12. Percutaneous papillary large balloon dilation during percutaneous cholangioscopic lithotripsy for the treatment of large bile-duct stones: a feasibility study.

    PubMed

    Han, Jee Young; Jeong, Seok; Lee, Don Haeng

    2015-03-01

    When access to a major duodenal papilla or endoscopic retrograde cholangiopancreatography has failed, percutaneous transhepatic cholangioscopic lithotripsy (PTCS-L) may be useful for removing common bile duct (CBD) stones. However, the feasibility and usefulness of percutaneous transhepatic papillary large-balloon dilation (PPLBD) during PTCS-L for the removal of large CBD stones has not been established. We aimed to determine the safety and efficacy of PPLBD for the treatment of large CBD stones. Eleven patients with large CBD stones in whom the access to the major papilla or bile duct had failed were enrolled prospectively. Papillary dilation was performed using a large (12-20 mm) dilation balloon catheter via the percutaneous transhepatic route. Post-procedure adverse events and efficacy of the stone retrieval were measured. The initial success rate of PPLBD was 100%. No patient required a basket to remove a stone after PPLBD. Electrohydraulic lithotripsy was required in 2 (18.2%) patients. The median time to complete stone removal after PPLBD was 17.8 min and no adverse events occurred after PPLBD. Asymptomatic hyperamylasemia was not encountered in any patients. This study indicates that PPLBD is safe and effective for removal of large CBD stones. PMID:25729250

  13. High-speed photography during laser-based gall bladder stone lithotripsy

    NASA Astrophysics Data System (ADS)

    Kokaj, Jahja O.

    2001-04-01

    Shadowgraphy of gall bladder stone, which is held by a basket and immersed in a civete is performed. The exposure time is determined by the time of a N-Dye laser pulse used as a lightening source for photography. The shadowgram is projected in the objective of a camera which is connected to a microscope. The light coming from the laser, illuminates the civete collecting optical information of the stone and physical phenomena appearing above the stone. On top of the stone a tip of optical fiber is fixed, which is used for transmitting Ho:Yag laser power to the stone. Using a computer and time delay the laser pulses used for destruction and illumination are synchronized. Since the N-Dye laser pulse is pico-second range and the Ho:Yag laser pulse is in the range of micro-second, many image frames are obtained within the time of one pulse applied during the destruction. It is known that in the process of stone destruction several phenomena like plume, plasma, shock wave and bubble formation take place. However, the physical mechanism of the stone destruction is not yet completely understood. From the obtained results the above phenomena are studied which gives new information and clue for understanding some of the mentioned phenomena. The laser power which is guided by an optical fiber into the gall bladder or kidney of the human body can damage the living tissue and cause some serious health problems. For this reason the fiber needs to be oriented properly during the action of the laser power.

  14. Modular flexible ureteroscopy and holmium laser lithotripsy for the treatment of renal and proximal ureteral calculi: A single-surgeon experience of 382 cases

    PubMed Central

    YAN, ZEJUN; XIE, GUOHAI; YUAN, HESHENG; CHENG, YUE

    2015-01-01

    To determine the safety and efficacy of modular flexible ureteroscopy and holmium laser lithotripsy for the treatment of renal and proximal ureteral calculi, a retrospective chart review of a single surgeon's 3-year modular flexible ureteroscopy experience was performed. All of the patients were treated with modular flexible ureteroscopy and holmium laser lithotripsy by a single surgeon. Stone-free status was defined as no fragments or a single fragment ≤4 mm in diameter at the 3-month follow-up. The procedure number, operative time, stone-free rates, repeat usage of the multilumen catheter, and perioperative complications were documented. The present study included 215 male patients and 167 female patients, with an average age of 48.5±13.7 years (range, 17–84 years). The mean stone size was 11.5±4.1 mm (range, 4–28 mm), and the mean total stone burden was 17.5±5.7 mm (range 15–46 mm). A total of 305 patients (79.8%) had a stone burden ≤20 mm, and 77 patients (20.2%) had a stone burden >20 mm. The mean number of primary procedures was 1.3±0.2 (range, 1–3). The stone-free rate following the first and the second procedure was 73.4 and 86.9%, respectively. The mean postoperative hospital stay was 3.1±1.2 days (range, 2–6 days). The highest clearance rates were observed for proximal ureteral stones (100%) and renal pelvic stones (88.7%), whereas the lowest clearance rates were observed for lower calyx stones (76.7%) and multiple calyx stones (77.8%). The higher the initial stone burden, the lower the postoperative stone-free rate (≤20 vs. >20 mm; 89.8 vs. 75.3%). The overall complication rate was 8.1%. The results of the present study suggest that modular flexible ureteroscopy with holmium laser lithotripsy may be considered the primary method for the treatment of renal and proximal ureteral calculi in select patients, due to its acceptable efficacy, low morbidity, and relatively low maintenance costs. PMID:26622508

  15. Effects of shock waves on growth of endothelial cells in vitro

    NASA Astrophysics Data System (ADS)

    Tamagawa, Masaaki; Kitayama, Masanobu; Iwakura, Seiya

    2005-04-01

    Recently shock wave phenomena in living tissues are being widely applied in the fields of medical and chemical engineering, such as extracorporeal shock wave lithotripsy, bioprocess for environmental protection and tissue engineering. In the field of tissue engineering, the bone therapy to regenerate the bone by extracorporeal shock waves shows the possibility for new therapy. In this paper, to investigate the effects of shock waves on the endothelial cells in vitro, the cells by plane shock waves are observed by microscope and the growth rate and others are measured by image processing. The peak pressure works on the endothelial cells in water at the test case is 0.4 MPa. After working shock waves on suspended cells and fixed cells, the disintegration, shape and growth are investigated. It is found that the younger generation cells have small differences of shape index, and the growth rate of the shock-worked cells from 0 to 4 h are clearly high compared with control ones. It is concluded that once shock waves worked, some of them are disintegrated, but the other has capacity to increase growth rate of cell culture in vitro.

  16. Study of fiber-tip damage mechanism during Ho:YAG laser lithotripsy by high-speed camera and the Schlieren method

    NASA Astrophysics Data System (ADS)

    Zhang, Jian J.; Getzan, Grant; Xuan, Jason R.; Yu, Honggang

    2015-02-01

    Fiber-tip degradation, damage, or burn back is a common problem during the ureteroscopic laser lithotripsy procedure to treat urolithiasis. Fiber-tip burn back results in reduced transmission of laser energy, which greatly reduces the efficiency of stone comminution. In some cases, the fiber-tip degradation is so severe that the damaged fiber-tip will absorb most of the laser energy, which can cause the tip portion to be overheated and melt the cladding or jacket layers of the fiber. Though it is known that the higher the energy density (which is the ratio of the laser energy fluence over the cross section area of the fiber core), the faster the fiber-tip degradation, the damage mechanism of the fibertip is still unclear. In this study, fiber-tip degradation was investigated by visualization of shockwave, cavitation/bubble dynamics, and calculus debris ejection with a high-speed camera and the Schlieren method. A commercialized, pulsed Ho:YAG laser at 2.12 um, 273/365/550-um core fibers, and calculus phantoms (Plaster of Paris, 10x10x10 mm cube) were utilized to mimic the laser lithotripsy procedure. Laser energy induced shockwave, cavitation/bubble dynamics, and stone debris ejection were recorded by a high-speed camera with a frame rate of 10,000 to 930,000 fps. The results suggested that using a high-speed camera and the Schlieren method to visualize the shockwave provided valuable information about time-dependent acoustic energy propagation and its interaction with cavitation and calculus. Detailed investigation on acoustic energy beam shaping by fiber-tip modification and interaction between shockwave, cavitation/bubble dynamics, and calculus debris ejection will be conducted as a future study.

  17. Unexpected waves

    NASA Astrophysics Data System (ADS)

    Gemmrich, J.; Garrett, C.

    2009-04-01

    Rogue waves have received considerable scientific attention in recent years. They are commonly defined as waves with height H ≥ 2.2Hs, where Hs is the significant wave height (typically estimated from records that are several tens of minutes long). This definition of rogue waves is solely based on the wave height. We suggest that the "unexpectedness" of large waves is also of great concern to mariners and beachcombers, and define "unexpected waves" as waves being twice as large as any of the preceding 30 waves. Our simulations suggest that, even in a Gaussian sea, unexpected waves might be as common as rogue waves occurring within a longer wave group. The return period of unexpected waves decreases if modifications of the wave shape due to phase locked second harmonics are allowed for. In particular, shallow water effects significantly increase the probability of occurrence of unexpected waves. We analyze historical Canadian wave buoy records from the Pacific and Atlantic in terms of unexpected waves, and find our simulations to be in agreement with the occurrence rates of unexpected waves obtained from these records. This agreement suggests that extreme waves in the ocean occur largely due to linear superposition

  18. Assessment of shock wave lithotripters via cavitation potential

    PubMed Central

    Iloreta, Jonathan I.; Zhou, Yufeng; Sankin, Georgy N.; Zhong, Pei; Szeri, Andrew J.

    2008-01-01

    A method to characterize shock wave lithotripters by examining the potential for cavitation associated with the lithotripter shock wave (LSW) has been developed. The method uses the maximum radius achieved by a bubble subjected to a LSW as a representation of the cavitation potential for that region in the lithotripter. It is found that the maximum radius is determined by the work done on a bubble by the LSW. The method is used to characterize two reflectors: an ellipsoidal reflector and an ellipsoidal reflector with an insert. The results show that the use of an insert reduced the −6 dB volume (with respect to peak positive pressure) from 1.6 to 0.4 cm3, the −6 dB volume (with respect to peak negative pressure) from 14.5 to 8.3 cm3, and reduced the volume characterized by high cavitation potential (i.e., regions characterized by bubbles with radii larger than 429 µm) from 103 to 26 cm3. Thus, the insert is an effective way to localize the potentially damaging effects of shock wave lithotripsy, and suggests an approach to optimize the shape of the reflector. PMID:19865493

  19. Perioperative cultures and the role of antibiotics during stone surgery

    PubMed Central

    Motamedinia, Piruz; Korets, Ruslan; Badalato, Gina

    2014-01-01

    Urinary tract infection and urosepsis are the most common complications associated with the procedures urologists employ to manage stone disease. Recommendations regarding antibiotic prophylaxis and utilization of perioperative urine and stone culture prior to shockwave lithotripsy (SWL) or endoscopic intervention have evolved overtime. We sought to provide readers with a comprehensive consensus regarding these most recent recommendations. PMID:26816781

  20. Developing mobile lithotripsy services.

    PubMed

    Kates, J A; Krella, J M; Schoen, E J

    1990-03-01

    Today's health care environment forces hospitals to seek competitive advantages over other providers in their area, yet circumstances and situations exist where cooperation among providers is the only way to ensure the effective and efficient provision of quality care to area residents. In the case of new and expensive medical technology, cooperation may be necessary to make state-of-the-art treatment modalities available to the patient population in an affordable manner. The role of outside consultants and legal counsel should not be overlooked. Independent consultants can be a valuable resource in dealing with planning agencies and in preparing a Certificate of Need. In addition, reputable firms can lend additional credibility to the conduct of feasibility studies and the preparation of financial projections. Continuity in terms of staffing and committee representatives is also extremely important. In a process that covered a three-and-one-half year time period, participants can lose sight of the original goals of the venture and even interest in the project. Hospitals and physicians in northeastern Pennsylvania combined to provide an alternative to surgical intervention for the removal of kidney stones. The process was a lengthy and complicated one, but one that resulted in a service which, above all, is of benefit to those affected by kidney stone disease. The delivery network currently includes seven facilities, five as partners and two on a fee-for-service basis, with an additional five making application to join the program in the future.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:10104392

  1. Kidney stones - lithotripsy - discharge

    MedlinePlus

    ... days after this procedure. Drink a lot of water in the weeks after treatment. This helps pass any pieces of stone that still remain. Your health care provider may give you a medicine ... take and drink a lot of water if you have pain. You may need to ...

  2. Feasibility and efficacy of extracorporeal shock-wave lithotripsy using a new modified lateral position for the treatment of renal stones in obese patients.

    PubMed

    Karatzas, Anastasios; Gravas, Stavros; Tzortzis, Vassilios; Aravantinos, Evangelos; Zachos, Ioannis; Kalogeras, Nikolaos; Melekos, Michael

    2012-08-01

    The aim of our study was to evaluate the efficacy and safety of ESWL using a modified lateral position in obese patients with renal stones. Nineteen obese patients with renal stones were enrolled (group A). The mean stone diameter was 1.3 cm (0.7-1.9 cm). The mean BMI was 35.1 kg/m² (31-41 kg/m²). Patients were placed in the lateral position, with the energy source facing their body posteriorly and the site where the stone was located in direct contact with the water cushion. Success rate (defined as the percentage of patients who were stone-free or with insignificant fragments after 3 months), mean number of ESWL sessions, mean duration of ESWL session and complications were recorded. The results were compared with those of 17 obese patients (Group B) with similar baseline characteristics treated in the standard supine position. All ESWLs were performed using the Dornier lithotripter SII. Both success rate (68.4 vs. 64.7% for groups A and B, respectively) and mean number of sessions (2.2 vs. 2.6) did not differ significantly between the two groups (p = 0.5). Interestingly, the time required to complete ESWL was significantly shorter for group A patients (56 min) compared to group B (73 min) (p = 0.001). No severe complications (including hematoma, pyelonephritis) were recorded. Our data indicate that ESWL in the modified lateral position for renal calculi in obese patients seems to be feasible and safe. In addition, it is faster than in the supine position since it overcomes technical difficulties. Further studies with a large number of patients are required to support our findings. PMID:21847555

  3. Role of steroidal anti-inflammatory agent prior to intracorporeal lithotripsy under local anesthesia for ureterovesical junction calculus: A prospective randomized controlled study

    PubMed Central

    Lodh, Bijit; Singh, Kaku Akoijam; Sinam, Rajendra Singh

    2015-01-01

    Objective: The objective of the following study is to assess the effect of steroidal anti-inflammatory agent on the outcome of ureterorenoscopic lithotripsy (URSL) for ureterovesical junction (UVJ) calculus. Settings and Design: This was a prospective randomized controlled study conducted at the Department of Urology, Regional Institute of Medical Sciences, Imphal. Subjects and Methods: One hundred and twenty-six patients requiring ureteroscopic lithotripsy for UVJ calculus were randomly assigned into two groups. The study group received tablet deflazacort 30 mg once a day for 10 days prior to the procedure, whereas the control group did not receive such treatment. Parameters with respect to the outcome of the procedure were recorded for all patients in both groups. Statistical Analysis Used: Fisher's exact and independent t-test was used to compare the outcome between the groups where P < 0.05 was considered to be statistically significant. Results: There was significant statistical difference (P - 0.016) on the endoscopic appearance of the region of ureteric orifice in patients receiving steroidal anti-inflammatory agent compared with control. Severe procedure related pain and mean operative time was less in the study group compared to control (P - 0.020 and 0.031, respectively). Re-treatment rates in the study group were lower than the control group (4.76% vs. 17.46%) and found to be statistically significant (P - 0.044). It is found that computed tomography (CT) appearance (r - 0.399) and stone size (r - 0.410) strongly correlate with the endoscopic findings of the region of UVJ (P - 0.001). Conclusions: Inflamed and or obliterated ureteric orifice is the major constraints for stone clearance at ureterovesical junction. The present study showed the administration of tablet deflazacort (a steroidal anti-inflammatory agent) significantly improves the outcome of URSL under local anesthesia. We strongly recommend its use prior to URSL for UVJ calculus, especially for stone size ≥10.24 mm and on CT evidence of prominent soft tissue swelling at the UVJ. PMID:25835035

  4. Gravity Waves

    Atmospheric Science Data Center

    2013-04-19

    article title:  Gravity Waves Ripple over Marine Stratocumulus Clouds ... Imaging SpectroRadiometer (MISR), a fingerprint-like gravity wave feature occurs over a deck of marine stratocumulus clouds. Similar ... that occur when a pebble is thrown into a still pond, such "gravity waves" sometimes appear when the relatively stable and stratified air ...

  5. Development of Laser-induced Grating Spectroscopy for Underwater Temperature Measurement in Shock Wave Focusing Regions

    NASA Technical Reports Server (NTRS)

    Gojani, Ardian B.; Danehy, Paul M.; Alderfer, David W.; Saito, Tsutomu; Takayama, Kazuyoshi

    2003-01-01

    In Extracorporeal Shock Wave Lithotripsy (ESWL) underwater shock wave focusing generates high pressures at very short duration of time inside human body. However, it is not yet clear how high temperatures are enhanced at the spot where a shock wave is focused. The estimation of such dynamic temperature enhancements is critical for the evaluation of tissue damages upon shock loading. For this purpose in the Interdisciplinary Shock Wave Research Center a technique is developed which employs laser induced thermal acoustics or Laser Induced Grating Spectroscopy. Unlike most of gasdynamic methods of measuring physical quantities this provides a non-invasive one having spatial and temporal resolutions of the order of magnitude of 1.0 mm3 and 400 ns, respectively. Preliminary experiments in still water demonstrated that this method detected sound speed and hence temperature in water ranging 283 K to 333 K with errors of 0.5%. These results may be used to empirically establish the equation of states of water, gelatin or agar cells which will work as alternatives of human tissues.

  6. The Advantage of a Broad Focal Zone in SWL

    NASA Astrophysics Data System (ADS)

    Cleveland, Robin O.

    2008-09-01

    The evolution of lithotripters over the past 20 years has lead to the production of lithotripters with smaller focal zones (diameters 4-8 mm) than the first generation lithotripters (˜12 mm diameters) and with higher peak pressures (˜100 MPa compared to ˜40 MPa). At first glance it may seem beneficial to focus the acoustic energy more tightly onto the stone however clinical reports suggest that the narrower focal zones have poorer outcomes and more side effects. Here the impact of focal spot size on energy delivered to stones and the intensity delivered to tissue is considered by numerical modeling. It is shown that lithotripters with focal spots much larger than a stone are able to deliver similar energy to a stone as a narrow high pressure focal spot lithotripter. The reduction of energy delivered to the stone is exacerbated in the presence of motion. The larger focal spot lithotripters result in reduced incident intensity to the tissue. These results suggest that wide focal spot lithotripters have the potential to adequately fragment stones with a lower risk of side effects.

  7. The role of shear and longitudinal waves in the kidney stone comminution by a lithotripter shock pulse

    NASA Astrophysics Data System (ADS)

    Sapozhnikov, Oleg A.; Cleveland, Robin O.; Bailey, Michael R.

    2001-05-01

    Shock wave lithotripsy has been in clinical use for 20 years but there is no consensus as to the main mechanism of kidney stone comminution. Experiments show that several mechanisms might be involved, including cavitation, spallation, and dynamic fatigue. Until recently, little attention was paid to shear elasticity of the stone material, i.e., mechanical load was mainly attributed to the longitudinal waves. In a previous numerical study, we found that shear elasticity resulted in tremendous change in the stress pattern inside cylindrical stones. The numerical model has been extended to study elastic waves in asymmetric inhomogeneous stones. Strains and stresses in the stone are calculated based on the Lamé equation for an isotropic elastic medium. Lithotripter shock waves of various temporal and spatial profiles were considered according to several clinical models of lithotripters. Maximum compression, tensile and shear stresses are predicted as a function of stone dimension and shape. The model predicts that both shear and longitudinal waves play an important role in creating the regions of excess stresses where cracks can be formed. The results of modeling are compared with the experimental observations. [Work supported by ONRIFO, CRDF, NIH-Fogarty, RFBR, NIH, and Whitaker Foundation.

  8. Reorganization of pathological control functions of memory-A neural model for tissue healing by shock waves

    NASA Astrophysics Data System (ADS)

    Wess, Othmar

    2005-04-01

    Since 1980 shock waves have proven effective in the field of extracorporeal lithotripsy. More than 10 years ago shock waves were successfully applied for various indications such as chronic pain, non-unions and, recently, for angina pectoris. These fields do not profit from the disintegration power but from stimulating and healing effects of shock waves. Increased metabolism and neo-vascularization are reported after shock wave application. According to C. J. Wang, a biological cascade is initiated, starting with a stimulating effect of physical energy resulting in increased circulation and metabolism. Pathological memory of neural control patterns is considered the reason for different pathologies characterized by insufficient metabolism. This paper presents a neural model for reorganization of pathological reflex patterns. The model acts on associative memory functions of the brain based on modification of synaptic junctions. Accordingly, pathological memory effects of the autonomous nervous system are reorganized by repeated application of shock waves followed by development of normal reflex patterns. Physiologic control of muscle and vascular tone is followed by increased metabolism and tissue repair. The memory model may explain hyper-stimulation effects in pain therapy.

  9. Third Wave.

    ERIC Educational Resources Information Center

    Reed, Chris

    2000-01-01

    Third Wave is a Christian charity based in Derby (England) that offers training in vocational skills, preindustrial crafts, horticultural and agricultural skills, environmental education, and woodland survival skills to disadvantaged people at city and farm locations. Third Wave employs a holistic approach to personal development in a community…

  10. Correlation between the operation time using two different power settings of a Ho: YAG laser: laser power doesn’t influence lithotripsy time

    PubMed Central

    2013-01-01

    Background This study investigated the correlation between the operation time using two different power settings of a Ho: YAG laser. Findings A total of 68 patients underwent cystolithotripsy from April 2010 to October 2011 In Fifty-six of these patients underwent cystolithotripsy by one surgeon using a Ho: YAG laser for bladder calculi. This study assessed these patients in two groups; the 30 W laser generator group with the settings of 2.5 J x 5 Hz (30 W group) and the 100 W laser generator group as the settings of 3.5 J x 5 Hz (100 W group). The operation time in these two groups were assessed. A total of 56 patients including 45 male and 11 female patients that underwent cystolithotripsy using a Ho: YAG laser for bladder calculi by one surgeon were enrolled in this study. The patients’ characteristics including age (mean; 68.8 vs 68.4 yr), gender (male; 74.2 vs 88.0%), stone burden (mean; 34.9 vs 41.3 mm), number of stones (mean; 3.2 vs 2.0) and stone’s CT density (mean; 981.5 vs 902.0 HU) showed no significant differences. All patients were stone free following treatment. The median total length of the operation was 19 minutes (mean: 34.6 ± 36.1) in the 30 W group and 29 minutes (mean: 44.4 ± 38.8) in the 100 W group, which was not significantly different. Conclusions The results showed that the power settings of Ho: YAG laser show no differences in the operation time for bladder calculi lithotripsy. PMID:23510531

  11. A Review of Computational Methods in Materials Science: Examples from Shock-Wave and Polymer Physics

    PubMed Central

    Steinhauser, Martin O.; Hiermaier, Stefan

    2009-01-01

    This review discusses several computational methods used on different length and time scales for the simulation of material behavior. First, the importance of physical modeling and its relation to computer simulation on multiscales is discussed. Then, computational methods used on different scales are shortly reviewed, before we focus on the molecular dynamics (MD) method. Here we survey in a tutorial-like fashion some key issues including several MD optimization techniques. Thereafter, computational examples for the capabilities of numerical simulations in materials research are discussed. We focus on recent results of shock wave simulations of a solid which are based on two different modeling approaches and we discuss their respective assets and drawbacks with a view to their application on multiscales. Then, the prospects of computer simulations on the molecular length scale using coarse-grained MD methods are covered by means of examples pertaining to complex topological polymer structures including star-polymers, biomacromolecules such as polyelectrolytes and polymers with intrinsic stiffness. This review ends by highlighting new emerging interdisciplinary applications of computational methods in the field of medical engineering where the application of concepts of polymer physics and of shock waves to biological systems holds a lot of promise for improving medical applications such as extracorporeal shock wave lithotripsy or tumor treatment. PMID:20054467

  12. Experimentally validated multiphysics computational model of focusing and shock wave formation in an electromagnetic lithotripter

    PubMed Central

    Fovargue, Daniel E.; Mitran, Sorin; Smith, Nathan B.; Sankin, Georgy N.; Simmons, Walter N.; Zhong, Pei

    2013-01-01

    A multiphysics computational model of the focusing of an acoustic pulse and subsequent shock wave formation that occurs during extracorporeal shock wave lithotripsy is presented. In the electromagnetic lithotripter modeled in this work the focusing is achieved via a polystyrene acoustic lens. The transition of the acoustic pulse through the solid lens is modeled by the linear elasticity equations and the subsequent shock wave formation in water is modeled by the Euler equations with a Tait equation of state. Both sets of equations are solved simultaneously in subsets of a single computational domain within the BEARCLAW framework which uses a finite-volume Riemann solver approach. This model is first validated against experimental measurements with a standard (or original) lens design. The model is then used to successfully predict the effects of a lens modification in the form of an annular ring cut. A second model which includes a kidney stone simulant in the domain is also presented. Within the stone the linear elasticity equations incorporate a simple damage model. PMID:23927200

  13. Wave records and freak waves

    NASA Astrophysics Data System (ADS)

    Lechuga, Antonio

    2010-05-01

    Recently some evidences of freak waves have been found all over the world. 25-30 accidents have been reported to happen yearly due to them (Pelinovsky et al.). However direct measurements of freak or rogue waves is not easy .The main reason for it comes from its elusive quality as pointed out by researches and observers. Therefore to approach the problem we have to use whatever tool is available for us. One of them are wave records from buoys deployed near the presumed location. Thus we have to look for freak waves using data that have not got, in general, any anomalous wave (from the usual definition) but they present some characteristics that make it probable to induce its formation. We are going to carry out the analysis of the wave records close to locations where some accident has taken place, assuming nonlinear focussing as the framework of the involved theory. According to Janssen and Onorato et al. the main parameter to consider is kurtosis and through it the related BF index (BFI). This procedure, uniting statistical properties of random seas and a powerful theory, could in a near future to help us to foretell the appearance of rogue waves.

  14. Full-wave modeling of therapeutic ultrasound: Nonlinear ultrasound propagation in ideal fluids

    NASA Astrophysics Data System (ADS)

    Ginter, Siegfried; Liebler, Marko; Steiger, Eckard; Dreyer, Thomas; Riedlinger, Rainer E.

    2002-05-01

    The number of applications of high-intense, focused ultrasound for therapeutic purposes is growing. Besides established applications like lithotripsy, new applications like ultrasound in orthopedics or for the treatment of tumors arise. Therefore, new devices have to be developed which provide pressure waveforms and distributions in the focal zone specifically for the application. In this paper, a nonlinear full-wave simulation model is presented which predicts the therapeutically important characteristics of the generated ultrasound field for a given transducer and initial pressure signal. A nonlinear acoustic approximation in conservation form of the original hydrodynamic equations for ideal fluids rather than a wave equation provides the base for the nonlinear model. The equations are implemented with an explicit high-order finite-difference time-domain algorithm. The necessary coefficients are derived according to the dispersion relation preserving method. Simulation results are presented for two different therapeutic transducers: a self-focusing piezoelectric and one with reflector focusing. The computational results are validated by comparison with analytical solutions and measurements. An agreement of about 10% is observed between the simulation and experimental results.

  15. Making WAVES.

    ERIC Educational Resources Information Center

    Hindes, Victoria A.; Hom, Keri; Brookshaw, Keith

    About 46% of high school graduates enrolled in California State Universities need remedial courses in both math and English to prepare them for college level. These students typically earned B averages in their high school math and English classes. In order to address this issue, Shasta College launched Operation WAVES (Win by Achieving Valuable…

  16. On neutron surface waves

    SciTech Connect

    Ignatovich, V. K.

    2009-01-15

    It is shown that neutron surface waves do not exist. The difference between the neutron wave mechanics and the wave physics of electromagnetic and acoustic processes, which allows the existence of surface waves, is analyzed.

  17. Whip waves

    NASA Astrophysics Data System (ADS)

    McMillen, Tyler; Goriely, Alain

    2003-10-01

    The sound created by a whip as it cracks is produced by a mini-sonic boom created by a supersonic motion of the end of the whip. To create such a motion, one sends an impulse to the handle of the whip that travels to the end and accelerates the tip to supersonic speed. The impulse which creates a whip crack is studied as a wave travelling along an elastic rod. The whip is modeled as an inextensible, unshearable, inhomogeneous planar elastic rod. A crack is produced when a section of the whip breaks the sound barrier. We show by asymptotic analysis that a wave travelling along the whip increases its speed as the radius decreases-as the whip tapers. A numerical scheme adapted to account for the varying cross-section and realistic boundary conditions is presented, and results of several numerical experiments are reported and compared to theoretical predictions. Finally, we describe the shape of the shock waves emitted by a material point on the whip travelling faster than the speed of sound.

  18. Making Waves: Seismic Waves Activities and Demonstrations

    NASA Astrophysics Data System (ADS)

    Braile, S. J.; Braile, L. W.

    2011-12-01

    The nature and propagation of seismic waves are fundamental concepts necessary for understanding the exploration of Earth's interior structure and properties, plate tectonics, earthquakes, and seismic hazards. Investigating seismic waves is also an engaging approach to learning basic principles of the physics of waves and wave propagation. Several effective educational activities and demonstrations are available for teaching about seismic waves, including the stretching of a spring to demonstrate elasticity; slinky wave propagation activities for compressional, shear, Rayleigh and Love waves; the human wave activity to demonstrate P- and S- waves in solids and liquids; waves in water in a simple wave tank; seismic wave computer animations; simple shake table demonstrations of model building responses to seismic waves to illustrate earthquake damage to structures; processing and analysis of seismograms using free and easy to use software; and seismic wave simulation software for viewing wave propagation in a spherical Earth. The use of multiple methods for teaching about seismic waves is useful because it provides reinforcement of the fundamental concepts, is adaptable to variable classroom situations and diverse learning styles, and allows one or more methods to be used for authentic assessment. The methods described here have been used effectively with a broad range of audiences, including K-12 students and teachers, undergraduate students in introductory geosciences courses, and geosciences majors.

  19. Robotic partial nephrectomy for caliceal diverticulum: a single-center case series.

    PubMed

    Akca, Oktay; Zargar, Homayoun; Autorino, Riccardo; Brandao, Luis Felipe; Laydner, Humberto; Samarasekera, Dinesh; Krishnan, Jayram; Noble, Mark; Haber, George-Pascal; Kaouk, Jihad H; Stein, Robert J

    2014-08-01

    The aim of this study is to examine the role of robotic partial nephrectomy (RPN) in the management of caliceal diverticula by assessing our single-center outcomes. Between July 2007 and July 2013, 7 of 670 patients underwent RPN procedures as a reason of caliceal diverticula. The indications for RPN in all cases were recurrent urinary tract infection and pain attributed to the diverticulum in addition to failed management by endourologic or extracorporeal shockwave lithotripsy (SWL) treatments. One patient with a calcified diverticulum and another with an unsuccessful SWL treatment underwent RPN without further endourologic intervention. The other five patients had a history of unsuccessful percutaneous nephrolithotomy (one case), ureteroscopy (URS) (two cases), and a combination of SWL+URS (two cases). No intraoperative or postoperative complications were observed. No patient was readmitted postoperatively. Unique features of the robotic platform facilitate the excision of diverticulum and subsequent kidney reconstruction for this benign, but complex pathology. PMID:24720868

  20. [Staghorn renal lithiasis treated with shock waves. Bacteriologic aspects].

    PubMed

    Durlach, R A; Toblli, J E; Gigler, C; Domecq, P; Vázquez, R; Cucci, V; Ramas, H; Ghirlanda, J M

    1994-01-01

    Struvite renal stones are caused by infection of the urine with bacteria that synthesize the enzyme urease. Ammonium is released by the breakdown of urea by urease, the urine becomes highly alkaline, and magnesium ammonium phosphate (struvite) and carbonate apatite crystallize. Incorporation of the infecting bacteria within the developing stone, results in a focus of infection that is resistant to conventional antimicrobial therapy, and which is manifested clinically by repeated urinary tract infection caused by persistent bacteriuria. Extracorporeal shock wave lithotripsy (ESWL) currently is accepted as the election treatment for most renal calculi. This trial examines the bacteriologic aspects pre and post-ESWL. Eighty adult patients, 47 females and 33 males, without clinical signs of urinary tract infections (UTI) were submitted to urine cultures pre and post-ESWL. The first 50 patients underwent during and post-ESWL, 150 blood cultures, which all proved to be negative, confirming very low risk of generalized sepsis. No patient presented fever, chills or rigors pre or postprocedures. With respect to urine cultures 43 patients (52.5%) had a pre-ESWL UTI, in comparison to 49 (60%) who had a UTI post-ESWL. The distribution of organisms pre and post-ESWL was as follows: Proteus mirabilis (22/22), Escherichia coli (11/11), Pseudomonas aeruginosa (4/5), Klebsiella pneumoniae (2/2), Enterobacter cloacae (0/1), Alcaligenes odorans (1/2) Enterococcus faecalis (1/3), Staphylococcus saprophyticus (1/2) and Candida albicans (1/1). In this study 6 patients presented bacteriuria post-ESWL probably due to bacteria from inside the calculi. According to these results, the risk of bacteremia seems to be very low. In 60% of staghorn renal stones we could demonstrate a bacterial infection. PMID:7658975

  1. Cutting Head for Ultrasonic Lithotripsy

    NASA Technical Reports Server (NTRS)

    Angulo, E. D.; Goodfriend, R.

    1987-01-01

    Kidney stones lodged in urinary tract disintegrated with increased safety and efficiency by cutting head attached to end of vibrated wire probe. Aligns probe with stone and enables probe to vibrate long enough to disintegrate stone. Design of cutting head reduces risk of metal-fatigue-induced breakage of probe tip leaving metal fragments in urinary tract. Teeth of cutting head both seat and fragment kidney stone, while extension of collar into catheter lessens mechanical strain in probe wire, increasing probe life and lessening danger of in situ probe breakage.

  2. Cutting head for ultrasonic lithotripsy

    NASA Technical Reports Server (NTRS)

    Anguluo, E. D.; Goodfriend, R. (Inventor)

    1985-01-01

    A cutting head for attachment to the end of the wire probe of an ultrasonic kidney stone disintegration instrument is described. The cutting head has a plurality of circumferentially arranged teeth formed at one end thereof to provide a cup shaped receptacle for kidney stones encountered during the disintegration procedure. An integral reduced diameter collar diminishes stress points in the wire and reduce breakage thereof.

  3. Cutting Head for Ultrasonic Lithotripsy

    NASA Technical Reports Server (NTRS)

    Angulo, Earl D. (Inventor); Goodfriend, Roger (Inventor)

    1989-01-01

    A cutting head for attachment to the end of the wire probe of an ultrasonic kidney stone disintegration instrument. The cutting head has a plurality of circumferentially arranged teeth formed at one end thereof to provide a cup-shaped receptacle for kidney stones encountered during the disintegration procedure. An integral reduced diameter collar diminishes stress points in the wire and reduces breakage thereof.

  4. Calyceal Diverticula: A Comprehensive Review

    PubMed Central

    Waingankar, Nikhil; Hayek, Samih; Smith, Arthur D; Okeke, Zeph

    2014-01-01

    Calyceal diverticula are rare outpouchings of the upper collecting system that likely have a congenital origin. Stones can be found in up to 50% of calyceal diverticula, although, over the combined reported series, 96% of patients presented with stones. Diagnosis is best made by intravenous urography or computed tomography urogram. Shock wave lithotripsy (SWL) is an option for first-line therapy in patients with stone-bearing diverticula that have radiologically patent necks in mid- to upper-pole diverticula and small stone burdens. Stone-free rates are the lowest with SWL, although patients report being asymptomatic following therapy in up to 75% of cases with extended follow-up. Ureteroscopy (URS) is best suited for management of anteriorly located mid- to upperpole diverticular stones. Drawbacks to URS include difficulty in identifying the ostium and low rate of obliteration. Percutaneous management is best used in posteriorly located mid- to lower-pole stones, and offers the ability to directly ablate the diverticulum. Percutaneous nephrolithotomy remains effective in the management of upperpole diverticula, but carries the risk of pulmonary complications unless subcostal access strategies such as triangulation or renal displacement are used. Laparoscopic surgery provides definitive management, but should be reserved for cases with large stones in anteriorly located diverticula with thin overlying parenchyma, and cases that are refractory to other treatment. This article reviews the current theories on the pathogenesis of calyceal diverticula. The current classification is examined in addition to the current diagnostic methods. Here we summarize an extensive review of the literature on the outcomes of the different treatment approaches. PMID:24791153

  5. ASTER Waves

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The pattern on the right half of this image of the Bay of Bengal is the result of two opposing wave trains colliding. This ASTER sub-scene, acquired on March 29, 2000, covers an area 18 kilometers (13 miles) wide and 15 kilometers (9 miles) long in three bands of the reflected visible and infrared wavelength region. The visible and near-infrared bands highlight surface waves due to specular reflection of sunlight off of the wave faces.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats, potentially active volcanoes, thermal pollution, and coral reef degradation; identifying crop stress; determining cloud morphology and physical properties; evaluating wetlands; mapping surface temperature of soils and geology; and measuring surface heat balance.

  6. MHD simple waves and the divergence wave

    SciTech Connect

    Webb, G. M.; Pogorelov, N. V.; Zank, G. P.

    2010-03-25

    In this paper we investigate magnetohydrodynamic (MHD) simple divergence waves in MHD, for models in which nablacentre dotBnot =0. These models are related to the eight wave Riemann solvers in numerical MHD, in which the eighth wave is the divergence wave associated with nablacentre dotBnot =0. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field induction in the MHD case) depend on a single phase function phi. We consider the form of the MHD equations used by both Powell et al. and Janhunen. It is shown that the Janhunen version of the equations possesses fully nonlinear, exact simple wave solutions for the divergence wave, but no physically meaningful simple divergence wave solution exists for the Powell et al. system. We suggest that the 1D simple, divergence wave solution for the Janhunen system, may be useful for the testing and validation of numerical MHD codes.

  7. Waves and Tsunami Project

    ERIC Educational Resources Information Center

    Frashure, K. M.; Chen, R. F.; Stephen, R. A.; Bolmer, T.; Lavin, M.; Strohschneider, D.; Maichle, R.; Micozzi, N.; Cramer, C.

    2007-01-01

    Demonstrating wave processes quantitatively in the classroom using standard classroom tools (such as Slinkys and wave tanks) can be difficult. For example, waves often travel too fast for students to actually measure amplitude or wavelength. Also, when teaching propagating waves, reflections from the ends set up standing waves, which can confuse…

  8. Waves and Tsunami Project

    ERIC Educational Resources Information Center

    Frashure, K. M.; Chen, R. F.; Stephen, R. A.; Bolmer, T.; Lavin, M.; Strohschneider, D.; Maichle, R.; Micozzi, N.; Cramer, C.

    2007-01-01

    Demonstrating wave processes quantitatively in the classroom using standard classroom tools (such as Slinkys and wave tanks) can be difficult. For example, waves often travel too fast for students to actually measure amplitude or wavelength. Also, when teaching propagating waves, reflections from the ends set up standing waves, which can confuse

  9. Auroral plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1989-01-01

    A review is given of auroral plasma wave phenomena, starting with the earliest ground-based observations and ending with the most recent satellite observations. Two types of waves are considered, electromagnetic and electrostatic. Electromagnetic waves include auroral kilometric radiation, auroral hiss, ELF noise bands, and low-frequency electric and magnetic noise. Electrostatic waves include upper hybrid resonance emissions, electron cyclotron waves, lower hybrid waves, ion cyclotron waves and broadband electrostatic noise. In each case, a brief overview is given describing the observations, the origin of the instability, and the role of the waves in the physics of the auroral acceleration region.

  10. Electromagnetic waves in gravitational wave spacetimes

    NASA Astrophysics Data System (ADS)

    Bini, Donato; Fortini, Pierluigi; Haney, Maria; Ortolan, Antonello

    2011-12-01

    We have considered the propagation of electromagnetic waves in a spacetime representing an exact gravitational plane wave and calculated the induced changes on the four-potential field Aμ of a plane electromagnetic wave. By choosing a suitable photon round trip in a Michelson interferometer, we have been able to identify the physical effects of the exact gravitational wave on the electromagnetic field, i.e. phase shift, change of the polarization vector, angular deflection and delay. These results have been exploited to study the response of an interferometric gravitational wave detector beyond the linear approximation of the general theory of relativity.

  11. A Simple Wave Driver

    ERIC Educational Resources Information Center

    Temiz, Burak Kagan; Yavuz, Ahmet

    2015-01-01

    This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the

  12. Financial Rogue Waves

    NASA Astrophysics Data System (ADS)

    Yan, Zhen-Ya

    2010-11-01

    We analytically give the financial rogue waves in the nonlinear option pricing model due to Ivancevic, which is nonlinear wave alternative of the BlackScholes model. These rogue wave solutions may he used to describe the possible physical mechanisms for rogue wave phenomenon in financial markets and related fields.

  13. A Simple Wave Driver

    ERIC Educational Resources Information Center

    Temiz, Burak Kagan; Yavuz, Ahmet

    2015-01-01

    This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the…

  14. Planetary plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1993-01-01

    The primary types of plasma waves observed in the vicinity of the planets Venus, Mars, Earth, Jupiter, Saturn, Uranus, and Neptune are described. The observations are organized according to the various types of plasma waves observed, ordered according to decreasing distance from the planet, starting from the sunward side of the planet, and ending in the region near the closest approach. The plasma waves observed include: electron plasma oscillations and ion acoustic waves; trapped continuum radiation; electron cyclotron and upper hybrid waves; whistler-mode emissions; electrostatic ion cyclotron waves; and electromagnetic ion cyclotron waves.

  15. Photoelectron wave function in photoionization: plane wave or Coulomb wave?

    PubMed

    Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I

    2015-11-19

    The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion. PMID:26509428

  16. Wave-pinned filaments of scroll waves

    NASA Astrophysics Data System (ADS)

    Bánsági, Tamás; Meyer, Kevin J.; Steinbock, Oliver

    2008-03-01

    Scroll waves are three-dimensional excitation patterns that rotate around one-dimensional space curves. Typically these filaments are closed loops or end at the system boundary. However, in excitable media with anomalous dispersion, filaments can be pinned to the wake of traveling wave pulses. This pinning is studied in experiments with the 1,4-cyclohexanedione Belousov-Zhabotinsky reaction and a three-variable reaction-diffusion model. We show that wave-pinned filaments are related to the coexistence of rotating and translating wave defects in two dimensions. Filament pinning causes a continuous expansion of the total filament length. It can be ended by annihilating the pinning pulse in a frontal wave collision. Following such an annihilation, the filament connects itself to the system boundary. Its postannihilation shape that is initially the exposed rim of the scroll wave unwinds continuously over numerous rotation periods.

  17. Global Coronal Waves

    NASA Astrophysics Data System (ADS)

    Chen, P. F.

    This paper uses "Extreme Ultraviolet (EUV) waves" for any kind of wavelike phenomena observed in EUV and 'Extreme Imaging Telescope (EIT) waves" for the phenomenon discovered by Thompson. The discovery and the ensuing interpretation of the globally propagating waves in the solar corona, that is, "EIT waves", are an excellent example to illustrate how complicated a propagating pattern would be. The chapter reviews the progress on this global coronal wave in the past 18 years. The authors argued that the faster wave corresponds to the coronal Moreton wave, therefore, it is of fast mode; the slower one corresponds to the diffuse "EIT wave" as discovered by Thompson. In principle, the authors might adjust the coronal magnetic field in order to make the derived velocity of the slower type of EUV wave best match the observation, and then consider the corresponding three-dimensional magnetic field to represent the real corona.

  18. Generalized viscoelastic wave equation

    NASA Astrophysics Data System (ADS)

    Wang, Yanghua

    2016-02-01

    This paper presents a generalized wave equation which unifies viscoelastic and pure elastic cases into a single wave equation. In the generalized wave equation, the degree of viscoelasticity varies between zero and unity, and is defined by a controlling parameter. When this viscoelastic controlling parameter equals to 0, the viscous property vanishes and the generalized wave equation becomes a pure elastic wave equation. When this viscoelastic controlling parameter equals to 1, it is the Stokes equation made up of a stack of pure elastic and Newtonian viscous models. Given this generalized wave equation, an analytical solution is derived explicitly in terms of the attenuation and the velocity dispersion. It is proved that, for any given value of the viscoelastic controlling parameter, the attenuation component of this generalized wave equation perfectly satisfies the power laws of frequency. Since the power laws are the fundamental characteristics in physical observations, this generalized wave equation can well represent seismic wave propagation through subsurface media.

  19. ULF Waves at Mercury

    NASA Astrophysics Data System (ADS)

    Kim, E.-H.; Boardsen, S. A.; Johnson, J. R.; Slavin, J. A.

    This chapter provides a brief overview of the observed characteristics of ultra-low-frequency (ULF) waves at Mercury. It shows how field-aligned propagating ULF waves at Mercury can be generated by externally driven fast compressional waves (FWs) via mode conversion at the ion-ion hybrid resonance. Then, the chapter reviews the interpretation that the strong magnetic compressional waves near and its harmonics observed with 20 of Mercury's magnetic equator could be the ion Bernstein wave (IBW) mode. A recent statistical study of ULF waves at Mercury based on MESSENGER data reported the occurrence and polarization of the detected waves. The chapter further introduces the field line resonance and the electromagnetic ion Bernstein waves to explain such waves, and shows that both theories can partially explain the observations.

  20. Gravity wave transmission diagram

    NASA Astrophysics Data System (ADS)

    Tomikawa, Y.

    2015-12-01

    A new method of obtaining power spectral distribution of gravity waves as a function of ground-based horizontal phase speed and propagation direction from airglow observations has recently been proposed. To explain gravity wave power spectrum anisotropy, a new gravity wave transmission diagram was developed in this study. Gravity wave transmissivity depends on the existence of critical and turning levels for waves that are determined by background horizontal wind distributions. Gravity wave transmission diagrams for different horizontal wavelengths in simple background horizontal winds with constant vertical shear indicate that the effects of the turning level reflection are significant and strongly dependent on the horizontal wavelength.

  1. A reduced-order, single-bubble cavitation model with applications to therapeutic ultrasound

    PubMed Central

    Kreider, Wayne; Crum, Lawrence A.; Bailey, Michael R.; Sapozhnikov, Oleg A.

    2011-01-01

    Cavitation often occurs in therapeutic applications of medical ultrasound such as shock-wave lithotripsy (SWL) and high-intensity focused ultrasound (HIFU). Because cavitation bubbles can affect an intended treatment, it is important to understand the dynamics of bubbles in this context. The relevant context includes very high acoustic pressures and frequencies as well as elevated temperatures. Relative to much of the prior research on cavitation and bubble dynamics, such conditions are unique. To address the relevant physics, a reduced-order model of a single, spherical bubble is proposed that incorporates phase change at the liquid-gas interface as well as heat and mass transport in both phases. Based on the energy lost during the inertial collapse and rebound of a millimeter-sized bubble, experimental observations were used to tune and test model predictions. In addition, benchmarks from the published literature were used to assess various aspects of model performance. Benchmark comparisons demonstrate that the model captures the basic physics of phase change and diffusive transport, while it is quantitatively sensitive to specific model assumptions and implementation details. Given its performance and numerical stability, the model can be used to explore bubble behaviors across a broad parameter space relevant to therapeutic ultrasound. PMID:22088026

  2. A model for damage of microheterogeneous kidney stones

    NASA Astrophysics Data System (ADS)

    Szeri, Andrew J.; Zohdi, Tarek I.; Blake, John R.

    2005-04-01

    In this paper, a theoretical framework is developed for the mechanics of kidney stones with an isotropic, random microstructure-such as those comprised of cystine or struvite. The approach is based on a micromechanical description of kidney stones comprised of crystals in a binding matrix. Stress concentration functions are developed to determine load sharing of the particle phase and the binding matrix phase. As an illustration of the theory, the fatigue of kidney stones subject to shock wave lithotripsy is considered. Stress concentration functions are used to construct fatigue life estimates for each phase, as a function of the volume fraction and of the mechanical properties of the constituents, as well as the loading from SWL. The failure of the binding matrix is determined explicitly in a model for the accumulation of distributed damage. Also considered is the amount of material damaged in a representative non-spherical collapse of a cavitation bubble near the stone surface. The theory can be used to assess the importance of microscale heterogeneity on the comminution of renal calculi and to estimate the number of cycles to failure in terms of measurable material properties.

  3. Dust-Acoustic Waves: Visible Sound Waves

    SciTech Connect

    Merlino, Robert L.

    2009-11-10

    A historical overview of some of the early theoretical and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some of the theoretical refinements that have been made, including the effects of collisions, plasma absorption, dust charge fluctuations, particle drifts and strong coupling effects are discussed. Some recent experimental findings and outstanding problems are also presented.

  4. Traveling Wave Demonstration.

    ERIC Educational Resources Information Center

    Kluger-Bell, Barry

    1995-01-01

    Describes a traveling-wave demonstration that uses inexpensive materials (crepe-paper streamers) and is simple to assemble and perform. Explains how the properties of light waves are illustrated using the demonstration apparatus. (LZ)

  5. Wave Meteorology and Soaring

    NASA Technical Reports Server (NTRS)

    Wiley, Scott

    2008-01-01

    This viewgraph document reviews some mountain wave turbulence and operational hazards while soaring. Maps, photographs, and satellite images of the meteorological phenomena are included. Additionally, photographs of aircraft that sustained mountain wave damage are provided.

  6. Gravity waves from thunderstorms

    NASA Technical Reports Server (NTRS)

    Balachandran, N. K.

    1980-01-01

    Gravity waves generated by severe thunderstorms in the eastern Ohio-Pennsylvania area were recorded by an array of microbarovariographs at Palisades, New York and by standard microbarographs across northeastern United States. The waves were associated with the cold mesohigh from the outflow of the thunderstorms. Along their path the waves apparently triggered new thunderstorms. The waves were observed to propagate with the velocity of the wind just below the tropopause. The long-distance propagation of the waves is explained by the presence of a dust associated with the critical level (steering level), in agreement with the derivations given by Lindzen and Tung (1976). The dust was directional and waves were absent to the west of the generating area. In the generating area wave-CISK might have been operating. Sharp vertical temperature gradients associated with the passage of the waves were observed by temperature sensors on a tower.

  7. Detonation Wave Profile

    SciTech Connect

    Menikoff, Ralph

    2015-12-14

    The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.

  8. Oceanic wave measurement system

    NASA Technical Reports Server (NTRS)

    Holmes, J. F.; Miles, R. T. (Inventor)

    1980-01-01

    An oceanic wave measured system is disclosed wherein wave height is sensed by a barometer mounted on a buoy. The distance between the trough and crest of a wave is monitored by sequentially detecting positive and negative peaks of the output of the barometer and by combining (adding) each set of two successive half cycle peaks. The timing of this measurement is achieved by detecting the period of a half cycle of wave motion.

  9. Waves of Hanta

    NASA Astrophysics Data System (ADS)

    Abramson, Guillermo

    2003-03-01

    A spatially extended model of the hantavirus infection in deer mice is analyzed. Traveling waves solutions of the infected and susceptible populations are studied in different regimes, controlled by an environmental parameter. The wave of infection is shown to lag behind the wave of susceptible population, and the delay between the two is analyzed numerically and through a piecewise linearization.

  10. Paper terahertz wave plates.

    PubMed

    Scherger, Benedikt; Scheller, Maik; Vieweg, Nico; Cundiff, Steven T; Koch, Martin

    2011-12-01

    We present a low-cost terahertz wave plate based on form birefringence fabricated using ordinary paper. Measurements of the transfer function of the wave plate between polarizers closely agree with predictions based on the measured complex indices of refraction of the effective medium. For the design frequency, the dependence on wave plate angle also agrees with theory. PMID:22273881

  11. ULF waves at Mercury

    NASA Astrophysics Data System (ADS)

    Kim, E. H.; Boardsen, S. A.; Johnson, J.; Slavin, J. A.

    2014-12-01

    Ion cyclotron frequency range waves (or electromagnetic ion cyclotron wave, EMIC) have been often observed at Mercury's magnetospheres. The previous statistical study showed the magnetic compressional component is dominant near the magnetic equator and the transition from compressional to transverse dominance occurs roughly at magnetic latitudes of ±20˚. Because the observed waves also often show linearly polarization, the field-line resonance in the single or multiple ion plasmas have been suggested to discuss such waves. On the other hand, electromagnetic ion Bernstein wave (IBW) is also suggested because of strong power of compressional component. In this talk, we will address both field-line resonance and electromagnetic IBWs in order to discuss the ULF waves detected from MESSENGER. We adopted 2D full-wave code that recently developed at Princeton Plasma Physics Laboratory. When compressional fast waves are launched in the outer magnetosphere, the waves propagate to inner magnetosphere and strong field-aligned waves are mode-converted from the incoming compressional waves. Such mode-converted waves globally oscillate and have strong transverse components. Near the magnetic equator, due to mixture of incoming compressional waves and mode-converted field-line resonance, magnetic compressional component is dominant while transverse component is dominant off the equator, which is consistent with statistical study. We also used warm plasma ray-tracing to explore the propagation of the IBW mode in a dipole magnetic field and found that the electromagnetic IBWs are highly unstable to the proton loss cone distribution function and the wave's group velocity is highly field aligned. The wavelength of this mode is on the order of 100 km. We also discovered that as the waves propagate they can become highly compressional even in a moderate proton beta ~0.05 to 0.54 plasma, which is also consistent with observations.

  12. Wave turbulence in annular wave tank

    NASA Astrophysics Data System (ADS)

    Onorato, Miguel; Stramignoni, Ettore

    2014-05-01

    We perform experiments in an annular wind wave tank at the Dipartimento di Fisica, Universita' di Torino. The external diameter of the tank is 5 meters while the internal one is 1 meter. The tank is equipped by two air fans which can lead to a wind of maximum 5 m/s. The present set up is capable of studying the generation of waves and the development of wind wave spectra for large duration. We have performed different tests including different wind speeds. For large wind speed we observe the formation of spectra consistent with Kolmogorv-Zakharov predictions.

  13. Detectors of gravitational waves

    NASA Astrophysics Data System (ADS)

    Pizzella, G.

    Gravitational waves Motion of test bodies in a g.w. field Energy carried by gravitational waves Gravitational-wave sources Spinning star Double-star systems Fall into a Schwarzschild black hole Radiation from gravitational collapse Gravitational-wave detectors The nonresonant detectors The resonant detectors Electromechnical transducers Piezoelectric ceramic The capacitor The inductor Data analysis The Brownian noise The back-action The wide-band noise, data analysis and optimization The resonant transducer The Wiener-Kolmogoroff filter The cross-section and the effective temperature The antenna bandwidth The gravitational-wave experiments in the world The laser interferometers The resonant detectors

  14. Fast wave current drive

    SciTech Connect

    Goree, J.; Ono, M.; Colestock, P.; Horton, R.; McNeill, D.; Park, H.

    1985-07-01

    Fast wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfven wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into the plasma by fast wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast wave current drive is appropriate for higher plasma densities.

  15. Cycloidal Wave Energy Converter

    SciTech Connect

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  16. Trapped rossby waves

    PubMed

    Muller

    2000-02-01

    The possibility of tidal dynamics at strictly imaginary Lamb parameters has been known for more than three decades. The present paper explores the prevailing physics in this parameter regime. To this end, basic features of the global circulation such as baroclinicity and geostrophy have to be incorporated into tidal dynamics. The tidal equations of the thermal wind are readily obtained in the framework of spherical bishallow water theory. Density surfaces of a circulation with available potential energy alter the spatial inhomogenities of the generic tidal problem. Wave dynamics in an inhomogeneous medium are characterized not only by a dispersion relation but also by a wave guide geography: significant wave amplitudes are trapped in specific regions of frequency-dependent width. As an inherently global issue, evaluation of the Rossby wave guide geography for a given circulation cannot rely on the familiar regional filters of tidal theory. On the global domain, the Rossby wave specification is given by the Margules filter. A thermal wind is stable against nondivergent Rossby wave disturbances. Rossby waves propagating with a geostrophic wind are governed by prolate dynamics (real Lamb parameters) while imaginary Lamb parameters emerge for the oblate dynamics of Rossby waves running against a geostrophic wind. Oblate Rossby wave dynamics include pole-centered wave guides and very low-frequency disturbances propagating eastward against a westward wind. PMID:11046427

  17. The biological effects of extracorporeal shock wave therapy (eswt) on tendon tissue.

    PubMed

    Notarnicola, Angela; Moretti, Biagio

    2012-01-01

    There is currently great interest in the use of Extracorporeal Shock Wave Therapy (ESWT) and in clarifying the mechanisms of action in tendon pathologies. The success rate ranges from 60% to 80% in epicondylitis, plantar fasciitis, cuff tendinitis, trocanteritis, Achilles tendinitis or jumper's knee. In contrast to urological treatments (lithotripsy), where shockwaves are used to disintegrate renal stones, in musculoskeletal treatments (orthotripsy), shockwaves are not being used to disintegrate tissues, but rather to microscopically cause interstitial and extracellular biological responses and tissue regeneration. The researchers are interesting to investigate the biological effects which support the clinical successes. Some authors speculated that shockwaves relieve pain in insertional tendinopathy by hyper-stimulation analgesia. Many recent studies demonstrated the modulations of shockwave treatment including neovascularization, differentiation of mesenchymal stem cells and local release of angiogenetic factors. The experimental findings confirm that ESWT decrease the expression of high levels of inflammatory mediators (matrix metalloproteinases and inter-leukins). Therefore, ESWT produces a regenerative and tissue-repairing effect in musculoskeletal tissues, not merely a mechanical disintegrative effect as generally before assumed. Based on the encouraging results of clinical and experimental studies, the potential of ESWT appears to be emerging. The promising outcome after this non-invasive treatment option in tendinitis care justifies the indication of shockwave therapy. Further studies have to be performed in order or determine optimum treatment parameters and will bring about an improvement in accordance with evidence-based medicine. Finally, meta-analysis studies are necessary to demonstrate the efficacy and safety of ESWT in treating tendinopathies. PMID:23738271

  18. RADIATION WAVE DETECTION

    DOEpatents

    Wouters, L.F.

    1960-08-30

    Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.

  19. Nonlinear Internal Waves Generation

    NASA Astrophysics Data System (ADS)

    Kanarska, Y.; McWilliams, J. C.; Shchepetkin, A.

    2006-12-01

    We present several studies of the generation of internal waves to explain the occurrence and properties of nonlinear waves in the South China Sea region. According to the fundamental work of Bell (1975), for linear generation of internal waves over topography (height h and length L) in medium with buoyancy frequency N by oscillatory flow with frequency ω 0 and amplitude U, two limiting case are possible: (a) a slowly varying version of lee waves in a steady stratified fluid if ω 0 / N → 0 (or some times replaced on more general condition U / ω 0 L >>1); (b) wave beams with wave slope √{{ω_02}-f2} / √ {N2 - ω 0 2} if U / ω 0 L → 0. Liner theory requires that wave slope be greater than topographic slope for both limits (i.e., subcritical topography). In realistic conditions of nonuniform stratification and finite depth the definition of characteristic regimes is more problematic e.g. ω 0 / N < < 0 in the pycnocline and, at the same time, U / ω 0 L is small. Moreover, in the case of finite depth topography (e.g. for the Luzon strait (h/H~ 0.9)) and a supercritical slope the generation of internal waves by the barotropic tide can be characterized by nonlinear processes such as flow separation, hydraulic jumps, and associated mixing that affect the bottom drag, wave generation and energy conversion and dissipation. We systematically study the impact of these nonlinearities on the wave field structure for mentioned conditions using idealized Gaussian ridge configuration and non-hydrostatic numerical model. Finally, the generation of tidal internal waves is investigated in a realistic regional configuration for the South China Sea, where the Kuroshio and other subtidal currents affect the generation and propagation of internal waves.

  20. Hysteresis of ionization waves

    SciTech Connect

    Dinklage, A.; Bruhn, B.; Testrich, H.; Wilke, C.

    2008-06-15

    A quasi-logistic, nonlinear model for ionization wave modes is introduced. Modes are due to finite size of the discharge and current feedback. The model consists of competing coupled modes and it incorporates spatial wave amplitude saturation. The hysteresis of wave mode transitions under current variation is reproduced. Sidebands are predicted by the model and found in experimental data. The ad hoc model is equivalent to a general--so-called universal--approach from bifurcation theory.

  1. Nondispersing wave packets

    SciTech Connect

    Maeda, H.; Gallagher, T. F.

    2007-03-15

    A nondispersing Rydberg wave packet can be made by applying a weak, linearly polarized field at the Kepler frequency of a Rydberg atom. The field phase locks the electron's motion to the microwave field, and the wave packet retains its spatial localization for times in excess of a microsecond. The electron's orbital oscillation leads to an oscillating dipole, which can either oscillate in phase or out of phase with the applied microwave field, creating wave packets analogous to Trojan and anti-Trojan wave packets described theoretically. Our observations can be described in both quantum mechanical and classical terms.

  2. Thermal-Wave Microscope

    NASA Technical Reports Server (NTRS)

    Jones, Robert E.; Kramarchuk, Ihor; Williams, Wallace D.; Pouch, John J.; Gilbert, Percy

    1989-01-01

    Computer-controlled thermal-wave microscope developed to investigate III-V compound semiconductor devices and materials. Is nondestructive technique providing information on subsurface thermal features of solid samples. Furthermore, because this is subsurface technique, three-dimensional imaging also possible. Microscope uses intensity-modulated electron beam of modified scanning electron microscope to generate thermal waves in sample. Acoustic waves generated by thermal waves received by transducer and processed in computer to form images displayed on video display of microscope or recorded on magnetic disk.

  3. Buckling of Scroll Waves

    NASA Astrophysics Data System (ADS)

    Dierckx, Hans; Verschelde, Henri; Selsil, Özgür; Biktashev, Vadim N.

    2012-10-01

    A scroll wave in a sufficiently thin layer of an excitable medium with negative filament tension can be stable nevertheless due to filament rigidity. Above a certain critical thickness of the medium, such a scroll wave will have a tendency to deform into a buckled, precessing state. Experimentally this will be seen as meandering of the spiral wave on the surface, the amplitude of which grows with the thickness of the layer, until a breakup to scroll wave turbulence happens. We present a simplified theory for this phenomenon and illustrate it with numerical examples.

  4. Optical rogue waves.

    PubMed

    Solli, D R; Ropers, C; Koonath, P; Jalali, B

    2007-12-13

    Recent observations show that the probability of encountering an extremely large rogue wave in the open ocean is much larger than expected from ordinary wave-amplitude statistics. Although considerable effort has been directed towards understanding the physics behind these mysterious and potentially destructive events, the complete picture remains uncertain. Furthermore, rogue waves have not yet been observed in other physical systems. Here, we introduce the concept of optical rogue waves, a counterpart of the infamous rare water waves. Using a new real-time detection technique, we study a system that exposes extremely steep, large waves as rare outcomes from an almost identically prepared initial population of waves. Specifically, we report the observation of rogue waves in an optical system, based on a microstructured optical fibre, near the threshold of soliton-fission supercontinuum generation--a noise-sensitive nonlinear process in which extremely broadband radiation is generated from a narrowband input. We model the generation of these rogue waves using the generalized nonlinear Schrödinger equation and demonstrate that they arise infrequently from initially smooth pulses owing to power transfer seeded by a small noise perturbation. PMID:18075587

  5. Caustics of atmospheric waves

    NASA Astrophysics Data System (ADS)

    Godin, Oleg A.

    2015-04-01

    Much like light and sound, acoustic-gravity waves in inhomogeneous atmosphere often have a caustic or caustics, where the ray theory predicts unphysical, divergent values of the wave amplitude and needs to be modified. Increase of the wave magnitude in the vicinity of a caustic makes such vicinities of primary interest in a number of problems, where a signal needs to be separated from a background noise. The value of wave focusing near caustics should be carefully quantified in order to evaluate possible nonlinearities promoted by the focusing. Physical understanding of the wave field in the vicinity of a caustic is also important for understanding of the wave reflection from and transmission (tunneling) through the caustic. To our knowledge, in contrast to caustics of acoustic, electromagnetic, and seismic waves as well as gravity waves in incompressible fluids, asymptotics of acoustic-gravity waves in the vicinity of a caustic have never been studied systematically. In this paper, we fill this gap. Atmospheric waves are considered as linear acoustic-gravity waves in a neutral, horizontally stratified, moving ideal gas of variable composition. Air temperature and wind velocity are assumed to be gradually varying functions of height, and slowness of these variations determines the large parameter of the problem. The scale height of the atmosphere can be large or small compared to the vertical wavelength. It is found that the uniform asymptotics of the wave field in the presence of a simple caustic can be expressed in terms of the Airy function and its derivative. As for the acoustic waves, the argument of the Airy function is expressed in terms of the eikonal calculated in the ray, or WKB, approximation. The geometrical, or Berry, phase, which arises in the consistent WKB approximation for acoustic-gravity waves, plays an important role in the caustic asymptotics. In the uniform asymptotics, the terms with the Airy function and its derivative are weighted by cosine and sine of the Berry phase, respectively. Explicit expressions are found for the amplitude factors in the dominant term of the uniform asymptotics. The amplitude factors can be expressed in terms of the Berry phase and the divergent wave amplitudes, which are found in the first WKB approximation, but remain finite at the caustic and in its vicinity. The uniform asymptotic expansion of acoustic-gravity waves in the presence of a caustic reduces to known results in the acoustic limit. Physical meaning and corollaries of the newly derived caustic asymptotics will be discussed.

  6. Ocean wave energy device

    SciTech Connect

    LaStella, J.P.; Tornabene, M.G.

    1986-07-15

    This patent describes an ocean wave energy device of a type including a buoy which reciprocates in a substantially vertical direction in response to successive waves of variable frequency passing therebeneath, the buoy being supported upon a substantially vertically oriented shaft and a power take off means including a shaft driven by movement of the vertical shaft. The improvement described consists of: wave frequency detector means for detecting the instantaneous frequency of a wave passing the detector and which will thereafter pass the buoy by monitoring the contour of each wave as such wave passes such wave frequency detector means and measuring the time interval between the crest and the following trough and between the trough and following crest of each such wave and means for imposing an artificial resonance to the buoy whereby the buoy resonance may be substantially conformed to the frequency of the wave at the time at the buoy, the artificial resonance imposing means including brake means for halting vertical movement of the buoy at substantially the uppermost and substantially the lowermost limits of vertical travel of the buoy.

  7. WAVES VHDL interface

    NASA Astrophysics Data System (ADS)

    Hanna, James P.

    1994-06-01

    The Waveform and Vector Exchange Specification (WAVES) is the Industry standard representation for digital stimulus and response for both the design and test communities. The VHSIC Hardware Description Language (VHDL) is the Industry standard language for the design, modeling, and simulation of digital electronics. Together VHDL and WAVES provide powerful support for top-down design and test methodologies and concurrent engineering practices. Although the syntax of WAVES is a subset of VHDL, no special support for using WAVES in a VHDL environment is defined within the language. This report will introduce and describe a VHDL package that was developed at Rome Laboratory to provide a software interface to support the use of WAVES in a VHDL environment. This VHDL package is referred to as the WAVES VHDL interface and has been proposed as a standard practice for a top-down design and test methodology using WAVES and VHDL. This report is not intended to provide a tutorial on VHDL or WAVES. It is assumed that the reader has an adequate understanding of the VHDL language and some modeling techniques. Further, it is assumed that the reader has an understanding of the WAVES language and can follow a simple Level 1 dataset description.

  8. Modal Waves Solved in Complex Wave Number

    NASA Astrophysics Data System (ADS)

    Xu, W.-J.; Jenot, F.; Ourak, M.

    2005-04-01

    A numerical algorithm is proposed for the resolution in complex domain of the ultrasonic modal waves from the characteristic equation of elastic structures. The method is applicable to any numerically available function given explicitly or implicitly. The complex root loci of the modal waves are constructed by varying other parameters. Different situations which can cause the roots searching and following failure are analysed and the corresponding solutions are proposed. The computation examples are given for a three layered adhesive joint and a composite plate.

  9. Stream breakup by waves

    NASA Astrophysics Data System (ADS)

    Samuelsen, G. S.; Ateshkadi, Arash

    1995-04-01

    An imaging technique is used to investigate the fluid dynamics associated with the breakup of a liquid jet by a passing transverse shock wave. This mechanism is believed to be a potential source of combustion instability in liquid propellant rocket engines. Combustion instability is caused by the release of heat in phase with a passing pressure disturbance. The jet/wave interaction causes rapid atomization and propellant redistribution, and enhances mixing, vaporization, and reaction rates. Knowledge of the breakup process aids in prediction of local heat release with respect to the passing wave and provides insight on its viability as a potential instability mechanism. The present shock tube study applies high-speed, high-resolution photography to explore the jet/wave interaction that might be experienced in a large scale liquid oxygen/hydrogen (LOX/H2) engine similar to the Space Shuttle Main Engine (SSME) or other such engines being considered for the next generation of launch systems. Fluid parameters deemed important were simulated as well as possible. Two types of wave induced breakup were examined: a constant velocity flow field (square wave) and an exponentially decaying velocity field (N-wave). Time resolved images of the jet/wave interaction indicate very rapid and fire atomization within 500 microns of impingement. Shock interaction with the primary atomization process produces a substantial change to the breakup mechanism and serves as a principal candidate for the promotion and acceleration of rocket engine instability. Results of the qualitative and quantitative study reveal that the step wave produces a long duration tangential and normal stress on the liquid column as compared to the N-wave. As a result, N-waves decelerate jet displacement and extend the jet breakup time.

  10. Oceanic-wave-measurement system

    NASA Technical Reports Server (NTRS)

    Holmes, J. F.; Miles, R. T.

    1980-01-01

    Barometer mounted on bouy senses wave heights. As wave motion raises and lowers barometer, pressure differential is proportional to wave height. Monitoring circuit samples barometer output every half cycle of wave motion and adds magnitudes of adjacent positive and negative peaks. Resulting output signals, proportional to wave height, are transmitted to central monitoring station.

  11. Power from Ocean Waves.

    ERIC Educational Resources Information Center

    Newman, J. N.

    1979-01-01

    Discussed is the utilization of surface ocean waves as a potential source of power. Simple and large-scale wave power devices and conversion systems are described. Alternative utilizations, environmental impacts, and future prospects of this alternative energy source are detailed. (BT)

  12. The Relativistic Wave Vector

    ERIC Educational Resources Information Center

    Houlrik, Jens Madsen

    2009-01-01

    The Lorentz transformation applies directly to the kinematics of moving particles viewed as geometric points. Wave propagation, on the other hand, involves moving planes which are extended objects defined by simultaneity. By treating a plane wave as a geometric object moving at the phase velocity, novel results are obtained that illustrate the

  13. The Relativistic Wave Vector

    ERIC Educational Resources Information Center

    Houlrik, Jens Madsen

    2009-01-01

    The Lorentz transformation applies directly to the kinematics of moving particles viewed as geometric points. Wave propagation, on the other hand, involves moving planes which are extended objects defined by simultaneity. By treating a plane wave as a geometric object moving at the phase velocity, novel results are obtained that illustrate the…

  14. Those Elusive Gravitational Waves

    ERIC Educational Resources Information Center

    MOSAIC, 1976

    1976-01-01

    The presence of gravitational waves was predicted by Einstein in his theory of General Relativity. Since then, scientists have been attempting to develop a detector sensitive enough to measure these cosmic signals. Once the presence of gravitational waves is confirmed, scientists can directly study star interiors, galaxy cores, or quasars. (MA)

  15. Spin Wave Directional Coupler

    NASA Astrophysics Data System (ADS)

    Nanayakkara, Kasuni; Kozhanov, Alexander

    2015-03-01

    Spin wave based logic devices are evolved as promising candidates for information processing due to potential in scaling and low power consumption. An element performing directional energy transfer between spin waveguides is required in order to implement existing proposed spin wave logic devices. Optical waveguide couplers are well studied and widely utilized in integrated and fiber optics applications. In this work we apply the concept of optical directional coupler to design and investigate the spin wave directional coupler comprised of the two ferromagnetic stripes separated by a nanometer scale air gap. Micromagnetic simulations and experimental spin wave energy transfer investigations using propagating spin wave spectroscopy were carried out. Spin waves are generated at one of the ends of the input waveguide while detected at remaining three ends of both spin waveguides. Spin wave coupling is investigated as the coupler geometry, biasing magnetic field amplitude and orientation and the spin wavelength are varied. Results are modeled as coupled backward volume magnetostatic spin wave modes. This work was supported in part by Georgia State University.

  16. Slow frictional waves

    NASA Astrophysics Data System (ADS)

    Viswanathan, Koushik; Sundaram, Narayan; Chandrasekar, Srinivasan

    Stick-slip, manifest as intermittent tangential motion between two dry solid surfaces, is a friction instability that governs diverse phenomena from automobile brake squeals to earthquakes. We show, using high-speed in situ imaging of an adhesive polymer interface, that low velocity stick-slip is fundamentally of three kinds, corresponding to passage of three different surface waves -- separation pulses, slip pulses and the well-known Schallamach waves. These waves, traveling much slower than elastic waves, have clear distinguishing properties. Separation pulses and Schallamach waves involve local interface separation, and propagate in opposite directions while slip pulses are characterized by a sharp stress front and do not display any interface detachment. A change in the stick-slip mode from separation to slip pulse is effected simply by increasing the normal force. Together, these three waves constitute all possible stick-slip modes in adhesive friction and are shown to have direct analogues in muscular locomotory waves in soft bodied invertebrates. A theory for slow wave propagation is also presented which is capable of explaining the attendant interface displacements, velocities and stresses.

  17. Wave action generator

    SciTech Connect

    Trepl, J.A.

    1983-04-05

    A wave motion motor is disclosed with an impeller moved by a float. The float is coupled to a swivel arrangement to turn in the direction of wave current and has an inclined underside. Also disclosed are means to adjust to tide level and triangular coupling means between the float and a flywheel.

  18. Acoustic wave analysis

    NASA Technical Reports Server (NTRS)

    Jackson, E. D.

    1968-01-01

    The primary mechanism for generation of acoustic waves in a centrifugal pump, due to the rotor/stator interaction, is an unsteady source at the entrance of the blade row as represented by the unsteady velocity field. The amplitudes of wave generated by pressure loading on the blades and by velocity boundary condition are compared.

  19. Advanced Gravitational Wave Detectors

    NASA Astrophysics Data System (ADS)

    Blair, D. G.; Howell, E. J.; Ju, L.; Zhao, C.

    2012-02-01

    Part I. An Introduction to Gravitational Wave Astronomy and Detectors: 1. Gravitational waves D. G. Blair, L. Ju, C. Zhao and E. J. Howell; 2. Sources of gravitational waves D. G. Blair and E. J. Howell; 3. Gravitational wave detectors D. G. Blair, L. Ju, C. Zhao, H. Miao, E. J. Howell, and P. Barriga; 4. Gravitational wave data analysis B. S. Sathyaprakash and B. F. Schutz; 5. Network analysis L. Wen and B. F. Schutz; Part II. Current Laser Interferometer Detectors: Three Case Studies: 6. The Laser Interferometer Gravitational-Wave Observatory P. Fritschel; 7. The VIRGO detector S. Braccini; 8. GEO 600 H. Lück and H. Grote; Part III. Technology for Advanced Gravitational Wave Detectors: 9. Lasers for high optical power interferometers B. Willke and M. Frede; 10. Thermal noise, suspensions and test masses L. Ju, G. Harry and B. Lee; 11. Vibration isolation: Part 1. Seismic isolation for advanced LIGO B. Lantz; Part 2. Passive isolation J-C. Dumas; 12. Interferometer sensing and control P. Barriga; 13. Stabilizing interferometers against high optical power effects C. Zhao, L. Ju, S. Gras and D. G. Blair; Part IV. Technology for Third Generation Gravitational Wave Detectors: 14. Cryogenic interferometers J. Degallaix; 15. Quantum theory of laser-interferometer GW detectors H. Miao and Y. Chen; 16. ET. A third generation observatory M. Punturo and H. Lück; Index.

  20. Spin-Wave Diode

    NASA Astrophysics Data System (ADS)

    Lan, Jin; Yu, Weichao; Wu, Ruqian; Xiao, Jiang

    2015-10-01

    A diode, a device allowing unidirectional signal transmission, is a fundamental element of logic structures, and it lies at the heart of modern information systems. The spin wave or magnon, representing a collective quasiparticle excitation of the magnetic order in magnetic materials, is a promising candidate for an information carrier for the next-generation energy-saving technologies. Here, we propose a scalable and reprogrammable pure spin-wave logic hardware architecture using domain walls and surface anisotropy stripes as waveguides on a single magnetic wafer. We demonstrate theoretically the design principle of the simplest logic component, a spin-wave diode, utilizing the chiral bound states in a magnetic domain wall with a Dzyaloshinskii-Moriya interaction, and confirm its performance through micromagnetic simulations. Our findings open a new vista for realizing different types of pure spin-wave logic components and finally achieving an energy-efficient and hardware-reprogrammable spin-wave computer.

  1. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L. (Inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  2. Holographic tunneling wave function

    NASA Astrophysics Data System (ADS)

    Conti, Gabriele; Hertog, Thomas; van der Woerd, Ellen

    2015-12-01

    The Hartle-Hawking wave function in cosmology can be viewed as a decaying wave function with anti-de Sitter (AdS) boundary conditions. We show that the growing wave function in AdS familiar from Euclidean AdS/CFT is equivalent, semiclassically and up to surface terms, to the tunneling wave function in cosmology. The cosmological measure in the tunneling state is given by the partition function of certain relevant deformations of CFTs on a locally AdS boundary. We compute the partition function of finite constant mass deformations of the O( N ) vector model on the round three sphere and show this qualitatively reproduces the behaviour of the tunneling wave function in Einstein gravity coupled to a positive cosmological constant and a massive scalar. We find the amplitudes of inhomogeneities are not damped in the holographic tunneling state.

  3. Project GlobWave

    NASA Astrophysics Data System (ADS)

    Busswell, Geoff; Ash, Ellis; Piolle, Jean-Francois; Poulter, David J. S.; Snaith, Helen; Collard, Fabrice; Sheera, Harjit; Pinnock, Simon

    2010-12-01

    The ESA GlobWave project is a three year initiative, funded by ESA and CNES, to service the needs of satellite wave product users across the globe. Led by Logica UK, with support from CLS, IFREMER, SatOC and NOCS, the project will provide free access to satellite wave data and products in a common format, both historical and in near real time, from various European and American SAR and altimeter missions. Building on the successes of similar projects for Sea Surface Temperature and ocean colour, the project aims to stimulate increased use and analysis of satellite wave products. In addition to common-format satellite data the project will provide comparisons with in situ measurements, interactive data analysis tools and a pilot spatial wave forecast verification scheme for operational forecast production centres. The project will begin operations in January 2010, with direction from regular structured user consultation.

  4. SQUARE WAVE AMPLIFIER

    DOEpatents

    Leavitt, M.A.; Lutz, I.C.

    1958-08-01

    An amplifier circuit is described for amplifying sigmals having an alternating current component superimposed upon a direct current component, without loss of any segnnent of the alternating current component. The general circuit arrangement includes a vibrator, two square wave amplifiers, and recombination means. The amplifier input is connected to the vibrating element of the vibrator and is thereby alternately applied to the input of each square wave amplifier. The detailed circuitry of the recombination means constitutes the novelty of the annplifier and consists of a separate, dual triode amplifier coupled to the output of each square wave amplifier with a recombination connection from the plate of one amplifier section to a grid of one section of the other amplifier. The recombination circuit has provisions for correcting distortion caused by overlapping of the two square wave voltages from the square wave amplifiers.

  5. Vector financial rogue waves

    NASA Astrophysics Data System (ADS)

    Yan, Zhenya

    2011-11-01

    The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black-Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields.

  6. Sculpting Waves (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Engheta, Nader

    2015-09-01

    In electronics controlling and manipulating flow of charged carriers has led to design of numerous functional devices. In photonics, by analogy, this is done through controlling photons and optical waves. However, the challenges and opportunities are different in these two fields. Materials control waves, and as such they can tailor, manipulate, redirect, and scatter electromagnetic waves and photons at will. Recent development in condensed matter physics, nanoscience, and nanotechnology has made it possible to tailor materials with unusual parameters and extreme characteristics and with atomic precision and thickness. One can now construct structures much smaller than the wavelengths of visible light, thus ushering in unprecedented possibilities and novel opportunities for molding fields and waves at the nanoscale with desired functionalities. At such subwavelength scales, sculpting optical fields and waves provides a fertile ground for innovation and discovery. I will discuss some of the exciting opportunities in this area, and forecast some future directions and possibilities.

  7. Observations of freak waves in random wave field in 2D experimental wave flume

    NASA Astrophysics Data System (ADS)

    Li, Jin-xuan; Li, Peng-fei; Liu, Shu-xue

    2013-10-01

    Long time series of wave field are experimentally simulated by JONSWAP spectra with random phases in a 2D wave flume. Statistic properties of wave surface, such as significant wave height, skewness and kurtosis, are analyzed, and the freak wave occurrence probability and its relations with Benjamin-Feir index (BFI) are also investigated. The results show that the skewness and the kurtosis are significantly dependent on the wave steepness, and the kurtosis increases along the flume when BFI is large. The freak waves are observed in random wave groups. They occur more frequently than expected, especially for the wave groups with large BFI.

  8. Secondary dust density waves excited by nonlinear dust acoustic waves

    SciTech Connect

    Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L.; Rosenberg, M.

    2012-08-15

    Secondary dust density waves were observed in conjunction with high amplitude (n{sub d}/n{sub d0}>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, {Gamma}{approx}1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.

  9. Standing Waves on a Shoestring.

    ERIC Educational Resources Information Center

    Hendrix, Laura

    1992-01-01

    Describes the construction of a wave generator used to review the algebraic relationships of wave motion. Students calculate and measure the weight needed to create tension to generate standing waves at the first eight harmonics. (MDH)

  10. Wave phenomena in sunspots

    NASA Astrophysics Data System (ADS)

    Löhner-Böttcher, Johannes

    2016-03-01

    Context: The dynamic atmosphere of the Sun exhibits a wealth of magnetohydrodynamic (MHD) waves. In the presence of strong magnetic fields, most spectacular and powerful waves evolve in the sunspot atmosphere. Allover the sunspot area, continuously propagating waves generate strong oscillations in spectral intensity and velocity. The most prominent and fascinating phenomena are the 'umbral flashes' and 'running penumbral waves' as seen in the sunspot chromosphere. Their nature and relation have been under intense discussion in the last decades. Aims: Waves are suggested to propagate upward along the magnetic field lines of sunspots. An observational study is performed to prove or disprove the field-guided nature and coupling of the prevalent umbral and penumbral waves. Comprehensive spectroscopic observations at high resolution shall provide new insights into the wave characteristics and distribution across the sunspot atmosphere. Methods: Two prime sunspot observations were carried out with the Dunn Solar Telescope at the National Solar Observatory in New Mexico and with the Vacuum Tower Telescope at the Teide Observatory on Tenerife. The two-dimensional spectroscopic observations were performed with the interferometric spectrometers IBIS and TESOS. Multiple spectral lines are scanned co-temporally to sample the dynamics at the photospheric and chromospheric layers. The time series (1 – 2.5 h) taken at high spatial and temporal resolution are analyzed according to their evolution in spectral intensities and Doppler velocities. A wavelet analysis was used to obtain the wave power and dominating wave periods. A reconstruction of the magnetic field inclination based on sunspot oscillations was developed. Results and conclusions: Sunspot oscillations occur continuously in spectral intensity and velocity. The obtained wave characteristics of umbral flashes and running penumbral waves strongly support the scenario of slow-mode magnetoacoustic wave propagation along the magnetic field lines. Signatures of umbral flashes and running penumbral waves are found already in the middle to upper photosphere. The signal and velocity increases toward the chromosphere. The shock wave behavior of the umbral flashes is confirmed by the evolving saw-tooth pattern in velocity and the strong downward motion of the plasma right after the passage of the shock front. The power spectra and peak periods of sunspot waves vary significantly with atmospheric altitude and position within the sunspot. In the vertical field of the umbra, the mixture of wave periods in the lower photosphere transforms into a domination of the 2.5min range in the upper photosphere and chromosphere. In the differentially inclined penumbra, the dominating wave periods increase with radial distance. The acoustic cut-off frequency which blocks the propagation of long-period waves is considered to increase with the field inclination and the ambient sound speed. The reconstruction of the sunspot's magnetic field inclination based on the peak period distribution yields consistent results with the inferred photospheric and extrapolated coronal magnetic field.

  11. Jovian Planetary Waves

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph

    1997-07-01

    The detection of slowly-moving, wave-like features in infrared {IR} observations of Jupiter {by us and others} has generated excitement. If these features are Rossby waves, they may probe the atmosphere down to the boundary with the planetary interior. Rossby waves cause zonal flows to oscillate about their characteristic latitude. We will search for such undulations in all available HST images of Jupiter's atmosphere, applying the automated searching techniques already successful in our infrared work. The amplitude of meridional oscillations would be 2,000 km, or 0decarcsec6 as seen from Earth. Detecting oscillations consistent with the wavenumbers and phases seen in IR data will establish that these features are indeed Rossby waves. Wave speeds, dispersion relations, longevity, vertical extent, and population statistics will all constrain models of planetary atmospheres, which have direct application to terrestrial meteorology. If, as we suspect, the waves have a large vertical extent, they may reflect the boundary conditions between the troposphere and planetary interior. Planetary interior modeling predicts convection organized into ``banana- cells'', which extend from pole to pole but are constrained in longitude. The number of cells strongly constrains the convection and is of interest to interior modelers. Detecting similar waves in both visible and IR data that maintain speed and wavenumber over a large range of latitudes would constitute a major step forward in measuring the conditions in the planetary interior.

  12. Undamped electrostatic plasma waves

    SciTech Connect

    Valentini, F.; Perrone, D.; Veltri, P.; Califano, F.; Pegoraro, F.; Morrison, P. J.; O'Neil, T. M.

    2012-09-15

    Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named corner modes. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the (k,{omega}{sub R}) plane ({omega}{sub R} being the real part of the wave frequency and k the wavenumber), away from the well-known 'thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower k-values and chopping the tail shifts them toward higher k-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.

  13. Wave action power plant

    SciTech Connect

    Lucia, L.V.

    1982-03-16

    A wave action power plant powered by the action of water waves has a drive shaft rotated by a plurality of drive units, each having a lever pivotally mounted on and extending from said shaft and carrying a weight, in the form of a float, which floats on the waves and rocks the lever up and down on the shaft. A ratchet mechanism causes said shaft to be rotated in one direction by the weight of said float after it has been raised by wave and the wave has passed, leaving said float free to move downwardly by gravity and apply its full weight to pull down on the lever and rotate the drive shaft. There being a large number of said drive units so that there are always some of the weights pulling down on their respective levers while other weights are being lifted by waves and thereby causing continuous rotation of the drive shaft in one direction. The said levers are so mounted that they may be easily raised to bring the weights into a position wherein they are readily accessible for cleaning the bottoms thereof to remove any accumulation of barnacles, mollusks and the like. There is also provided means for preventing the weights from colliding with each other as they independently move up and down on the waves.

  14. Glutamatergic Retinal Waves

    PubMed Central

    Kerschensteiner, Daniel

    2016-01-01

    Spontaneous activity patterns propagate through many parts of the developing nervous system and shape the wiring of emerging circuits. Prior to vision, waves of activity originating in the retina propagate through the lateral geniculate nucleus (LGN) of the thalamus to primary visual cortex (V1). Retinal waves have been shown to instruct the wiring of ganglion cell axons in LGN and of thalamocortical axons in V1 via correlation-based plasticity rules. Across species, retinal waves mature in three stereotypic stages (I–III), in which distinct circuit mechanisms give rise to unique activity patterns that serve specific functions in visual system refinement. Here, I review insights into the patterns, mechanisms, and functions of stage III retinal waves, which rely on glutamatergic signaling. As glutamatergic waves spread across the retina, neighboring ganglion cells with opposite light responses (ON vs. OFF) are activated sequentially. Recent studies identified lateral excitatory networks in the inner retina that generate and propagate glutamatergic waves, and vertical inhibitory networks that desynchronize the activity of ON and OFF cells in the wavefront. Stage III wave activity patterns may help segregate axons of ON and OFF ganglion cells in the LGN, and could contribute to the emergence of orientation selectivity in V1.

  15. Propagation of Moreton Waves

    NASA Astrophysics Data System (ADS)

    Zhang, Yuzong; Kitai, Reizaburo; Narukage, Noriyuki; Matsumoto, Takuma; Ueno, Satoru; Shibata, Kazunari; Wang, Jingxiu

    2011-06-01

    With the Flare-Monitoring Telescope (FMT) and Solar Magnetic Activity Research Telescope (SMART) at Hida observatory of Kyoto University, 13 events of Moreton waves were captured at Hα center, Hα ±0.5 Å, and Hα ±0.8 Å wavebands since 1997. With such samples, we have studied the statistical properties of the propagation of Moreton waves. Moreton waves were all restricted in sectorial zones with a mean value of 92°. However, their accompanying EIT waves, observed simultaneously with SOHO/EIT at extreme-ultraviolet wavelength, were very isotropic with a quite extended scope of 193°. The average propagation speeds of the Moreton waves and the corresponding EIT waves were 664 km s-1 and 205 km s-1, respectively. Moreton waves propagated either under large-scale close magnetic flux loops, or firstly in the sectorial region where two sets of magnetic loops separated from each other and diverged, and then stopped before the open magnetic flux region. The location swept by Moreton waves had a relatively weak magnetic field as compared to the magnetic fields at their sidewalls. The ratio of the magnetic flux density between the sidewall and the path falls in the range of 1.4 to 3.7 at a height of 0.01 solar radii. Additionally, we roughly estimated the distribution of the fast magnetosonic speed between the propagating path and sidewalls in an event on 1997 November 3, and found a relatively low-fast magnetosonic speed in the path. We also found that the propagating direction of Moreton waves coincided with the direction of filament eruption in a few well-observed events. This favors an interpretation of the ``Piston'' model, although further studies are necessary for any definitive conclusion.

  16. Wave-wave interactions in solar type III radio bursts

    SciTech Connect

    Thejappa, G.; MacDowall, R. J.

    2014-02-11

    The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.

  17. Acoustic and electromagnetic waves

    NASA Astrophysics Data System (ADS)

    Jones, Douglas Samuel

    Theoretical models of EM and acoustic wave propagation are presented in an introductory text intended for intermediate-level science and engineering students. Chapters are devoted to the mathematical representation of acoustic and EM fields, the special theory of relativity, radiation, resonators, waveguide theory, refraction, surface waves, scattering by smooth objects, diffraction by edges, and transient waves. The mathematical tools required for the analysis (Bessel, Legendre, Mathieu, parabolic-cylinder, and spheroidal functions; tensor calculus; and the asymptotic evaluation of integrals) are covered in appendices.

  18. The pendulum wave machine

    NASA Astrophysics Data System (ADS)

    Zetie, K. P.

    2015-05-01

    There are many examples on the internet of videos of pendulum wave machines and how to make them (for example, www.instructables.com/id/Wave-Pendulum/). The machine is simply a set of pendula of different lengths which, when viewed end on, produce wave-like patterns from the positions of the bobs. These patterns change with time, with new patterns emerging as the bobs change phase. In this article, the physics of the machine is explored and explained, along with tips on how to build such a device.

  19. Towards Gravitational Wave Astronomy

    NASA Astrophysics Data System (ADS)

    Losurdo, Giovanni

    This chapter is meant to introduce the reader to the forthcoming network of second-generation interferometric detectors of gravitational waves, at a time when their construction is close to completion and there is the ambition to detect gravitational waves for the first time in the next few years and open the way to gravitational wave astronomy. The legacy of first-generation detectors is discussed before giving an overview of the technology challenges that have been faced to make advanced detectors possible. The various aspects outlined here are then discussed in more detail in the subsequent chapters of the book.

  20. Demonstration of Shear Waves, Lamb Waves, and Rayleigh Waves by Mode Conversion.

    ERIC Educational Resources Information Center

    Leung, W. P.

    1980-01-01

    Introduces an experiment that can be demonstrated in the classroom to show that shear waves, Rayleigh waves, and Lamb waves can be easily generated and observed by means of mode conversion. (Author/CS)

  1. Lattice Waves, Spin Waves, and Neutron Scattering

    DOE R&D Accomplishments Database

    Brockhouse, Bertram N.

    1962-03-01

    Use of neutron inelastic scattering to study the forces between atoms in solids is treated. One-phonon processes and lattice vibrations are discussed, and experiments that verified the existence of the quantum of lattice vibrations, the phonon, are reviewed. Dispersion curves, phonon frequencies and absorption, and models for dispersion calculations are discussed. Experiments on the crystal dynamics of metals are examined. Dispersion curves are presented and analyzed; theory of lattice dynamics is considered; effects of Fermi surfaces on dispersion curves; electron-phonon interactions, electronic structure influence on lattice vibrations, and phonon lifetimes are explored. The dispersion relation of spin waves in crystals and experiments in which dispersion curves for spin waves in Co-Fe alloy and magnons in magnetite were obtained and the reality of the magnon was demonstrated are discussed. (D.C.W)

  2. Management of 1-2 cm renal stones

    PubMed Central

    Srivastava, Aneesh; Chipde, Saurabh S

    2013-01-01

    Introduction: The preferred treatment of >1cm stone is shockwave lithotripsy (SWL), while that of stone <2 cm is percutaneous nephrolithotomy (PCNL), but treatment of 1-2 cm renal stones is a controversial issue. We searched the literature to present a comprehensive review on this group. Material and Methods: Pubmed search of literature was done using the appropriate key words. We separately discussed the literature in lower polar and non lower polar stone groups. Results: For non lower polar renal stones of 1-2 cm, SWL is preferred approach, while for the lower polar stones; literature favors the use of PCNL. Retrograde intrarenal surgery (RIRS) is emerging as a promising technique for these calculi. Conclusions: Treatment of renal stone disease depends on stone and patient related, as well as on renal anatomical factors. Treatment should be individualized according to site of stone and available expertise. PMID:24082440

  3. Resonance wave pumping with surface waves

    NASA Astrophysics Data System (ADS)

    Carmigniani, Remi; Gharib, Morteza; Violeau, Damien; Caltech-ENPC Collaboration

    2015-11-01

    The valveless impedance pump enables the production or amplification of a flow without the use of integrated mobile parts, thus delaying possible failures. It is usually composed of fluid-filled flexible tubing, closed by solid tubes. The flexible tube is pinched at an off-centered position relative to the tube ends. This generates a complex wave dynamic that results in a pumping phenomenon. It has been previously reported that pinching at intrinsic resonance frequencies of the system results in a strong pulsating flow. A case of a free surface wave pump is investigated. The resonance wave pump is composed of a rectangular tank with a submerged plate separating the water into a free surface and a recirculation rectangular section connected through two openings at each end of the tank. A paddle placed at an off-center position above the submerged plate is controlled in a heaving motion with different frequencies and amplitudes. Similar to the case of valveless impedance pump, we observed that near resonance frequencies strong pulsating flow is generated with almost no oscillations. A linear theory is developed to pseudo-analytically evaluate these frequencies. In addition, larger scale applications were simulated using Smoothed Particle Hydrodynamic codes.

  4. Dark- and bright-rogue-wave solutions for media with long-wave-short-wave resonance.

    PubMed

    Chen, Shihua; Grelu, Philippe; Soto-Crespo, J M

    2014-01-01

    Exact explicit rogue-wave solutions of intricate structures are presented for the long-wave-short-wave resonance equation. These vector parametric solutions feature coupled dark- and bright-field counterparts of the Peregrine soliton. Numerical simulations show the robustness of dark and bright rogue waves in spite of the onset of modulational instability. Dark fields originate from the complex interplay between anomalous dispersion and the nonlinearity driven by the coupled long wave. This unusual mechanism, not available in scalar nonlinear wave equation models, can provide a route to the experimental realization of dark rogue waves in, for instance, negative index media or with capillary-gravity waves. PMID:24580164

  5. WindWaveFloat

    SciTech Connect

    Weinstein, Alla

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  6. Traveling-wave photodetector

    DOEpatents

    Hietala, V.M.; Vawter, G.A.

    1993-12-14

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size. 4 figures.

  7. Traveling-wave photodetector

    SciTech Connect

    Hietala, V.M.; Vawter, G.A.

    1992-12-31

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size.

  8. Sound wave transmission (image)

    MedlinePlus

    When sounds waves reach the ear, they are translated into nerve impulses. These impulses then travel to the brain where they are interpreted by the brain as sound. The hearing mechanisms within the inner ear, can ...

  9. Coupled wedge waves.

    PubMed

    Abell, Bradley C; Pyrak-Nolte, Laura J

    2013-11-01

    The interface between two wedges can be treated as a displacement discontinuity characterized by elastic stiffnesses. By representing the boundary between the two quarter-spaces as a displacement discontinuity, coupled wedge waves were determined theoretically to be dispersive and to depend on the specific stiffness of the non-welded contact between the two wedges. Laboratory experiments on isotropic and anisotropic aluminum confirmed the theoretical prediction that the velocity of coupled wedge waves, for a non-welded interface, ranged continuously from the single wedge wave velocity at low stress to the Rayleigh velocity as the load applied normal to the interface was increased. Elastic waves propagating along the coupled wedges of two quarter-spaces in non-welded contact are found to exist theoretically even when the material properties of the two quarter-spaces are the same. PMID:24180766

  10. Inventing the Wave Catchers.

    ERIC Educational Resources Information Center

    Fisher, Arthur

    1983-01-01

    Physicists and engineers advance the state of several arts in the design of gravitational-wave detection equipment. Provides background information and discusses the equipment (including laser interferometer), its use, and results of several experimental studies. (JN)

  11. Gravitational-wave joy

    NASA Astrophysics Data System (ADS)

    seyithocuk; jjeherrera; eltodesukane; GrahamRounce; rloldershaw; Beaker, Dr; Sandhu, G. S.; Ophiuchi

    2016-03-01

    In reply to the news article on the LIGO collaboration's groundbreaking detection of gravitational waves, first predicted by Einstein 100 years ago, from two black holes colliding (pp5, 6-7 and http://ow.ly/Ylsyt).

  12. Heat Wave Safety Checklist

    MedlinePlus

    ... heat has caused more deaths than all other weather events, including floods. A heat wave is a ... care for heat- related emergencies … ❏ Listen to local weather forecasts and stay aware of upcoming temperature changes. ❏ ...

  13. Observation of Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Gonzalez, Gabriela

    2016-06-01

    On September 14 2015, the two LIGO gravitational wave detectors in Hanford, Washington and Livingston, Louisiana registered a nearly simultaneous signal with time-frequency properties consistent with gravitational-wave emission by the merger of two massive compact objects. Further analysis of the signals by the LIGO Scientific Collaboration and Virgo Collaboration revealed that the gravitational waves detected by LIGO came from the merger of a binary black hole (BBH) system approximately 420 Mpc distant (z=0.09) with constituent masses of 36 and 29 M_sun. I will describe the details of the observation, the status of ground-based interferometric detectors, and prospects for future observations in the new era of gravitational wave astronomy.

  14. Traveling-wave photodetector

    DOEpatents

    Hietala, Vincent M.; Vawter, Gregory A.

    1993-01-01

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size.

  15. Wave Separation, Wave Intensity, the Reservoir-Wave Concept, and the Instantaneous Wave-Free Ratio: Presumptions and Principles.

    PubMed

    Westerhof, Nico; Segers, Patrick; Westerhof, Berend E

    2015-07-01

    Wave separation analysis and wave intensity analysis (WIA) use (aortic) pressure and flow to separate them in their forward and backward (reflected) waves. While wave separation analysis uses measured pressure and flow, WIA uses their derivatives. Because differentiation emphasizes rapid changes, WIA suppresses slow (diastolic) fluctuations of the waves and renders diastole a seemingly wave-free period. However, integration of the WIA-obtained forward and backward waves is equal to the wave separation analysis-obtained waves. Both the methods thus give similar results including backward waves spanning systole and diastole. Nevertheless, this seemingly wave-free period in diastole formed the basis of both the reservoir-wave concept and the Instantaneous wave-Free Ratio of (iFR) pressure and flow. The reservoir-wave concept introduces a reservoir pressure, Pres, (Frank Windkessel) as a wave-less phenomenon. Because this Windkessel model falls short in systole an excess pressure, Pexc, is introduced, which is assumed to have wave properties. The reservoir-wave concept, however, is internally inconsistent. The presumed wave-less Pres equals twice the backward pressure wave and travels, arriving later in the distal aorta. Hence, in contrast, Pexc is minimally affected by wave reflections. Taken together, Pres seems to behave as a wave, rather than Pexc. The iFR is also not without flaws, as easily demonstrated when applied to the aorta. The ratio of diastolic aortic pressure and flow implies division by zero giving nonsensical results. In conclusion, presumptions based on WIA have led to misconceptions that violate physical principles, and reservoir-wave concept and iFR should be abandoned. PMID:26015448

  16. Wave Propagation Program

    Energy Science and Technology Software Center (ESTSC)

    2007-01-08

    WPP is a massively parallel, 3D, C++, finite-difference elastodynamic wave propagation code. Typical applications for wave propagation with WPP include: evaluation of seismic event scenarios and damage from earthquakes, non-destructive evaluation of materials, underground facility detection, oil and gas exploration, predicting the electro-magnetic fields in accelerators, and acoustic noise generation. For more information, see User’s Manual [1].

  17. Sound Waves Levitate Substrates

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Wang, T. G.

    1982-01-01

    System recently tested uses acoustic waves to levitate liquid drops, millimeter-sized glass microballoons, and other objects for coating by vapor deposition or capillary attraction. Cylindrical contactless coating/handling facility employs a cylindrical acoustic focusing radiator and a tapered reflector to generate a specially-shaped standing wave pattern. Article to be processed is captured by the acoustic force field under the reflector and moves as reflector is moved to different work stations.

  18. Attosecond shock waves.

    PubMed

    Zhokhov, P A; Zheltikov, A M

    2013-05-01

    Shock-wave formation is a generic scenario of wave dynamics known in nonlinear acoustics, fluid dynamics, astrophysics, seismology, and detonation physics. Here, we show that, in nonlinear optics, remarkably short, attosecond shock transients can be generated through a strongly coupled spatial and temporal dynamics of ultrashort light pulses, suggesting a pulse self-compression scenario whereby multigigawatt attosecond optical waveforms can be synthesized. PMID:23683197

  19. Wave Propagation Program

    SciTech Connect

    2007-01-08

    WPP is a massively parallel, 3D, C++, finite-difference elastodynamic wave propagation code. Typical applications for wave propagation with WPP include: evaluation of seismic event scenarios and damage from earthquakes, non-destructive evaluation of materials, underground facility detection, oil and gas exploration, predicting the electro-magnetic fields in accelerators, and acoustic noise generation. For more information, see User?s Manual [1].

  20. The wave of the future - Searching for gravity waves

    NASA Astrophysics Data System (ADS)

    Goldsmith, Donald

    1991-04-01

    Research on gravity waves conducted by such scientists as Gamov, Wheeler, Weber and Zel'dovich is discussed. Particular attention is given to current trends in the theoretical analysis of gravity waves carried out by theorists Kip Thorne and Leonid Grishchuk. The problems discussed include the search for gravity waves; calculation of the types of gravity waves; the possibility of detecting gravity waves from localized sources, e.g., from the collision of two black holes in a distant galaxy or the collapse of a star, through the Laser Interferometer Gravitational Wave Observatory; and detection primordial gravity waves from the big bang.

  1. Traveling-Wave Tubes

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  2. Waving in the rain

    NASA Astrophysics Data System (ADS)

    Cavaleri, Luigi; Bertotti, Luciana; Bidlot, Jean-Raymond

    2015-05-01

    We consider the effect of rain on wind wave generation and dissipation. Rain falling on a wavy surface may have a marked tendency to dampen the shorter waves in the tail of the spectrum, the related range increasing with the rain rate. Historical and sailors' reports suggest that this leads to calmer wave conditions, certainly so for the action of breakers. We have explored this situation using a fully coupled meteorological-wave model system, adding an artificial rain rate-dependent damping of the tail. Contrarily to direct marine experience, the experimental results show higher wind speeds and wave heights. A solid indication of the truth is achieved with the direct comparison between operational model (where rain effect is ignored) and measured data. These strongly support the sailors' claims of less severe wave conditions under heavy rain. This leads to a keen analysis of the overall process, in particular on the role of the tail of the spectrum in modulating the wind input and the white-capping, and how this is presently modeled in operational activity. We suggest that some revision is due and that the relationship between white-capping and generation by wind is deeper and more implicative than presently generally assumed.

  3. The Juno Waves investigation

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Kirchner, D. L.; Hospodarsky, G. B.; Mokrzycki, B. T.; Averkamp, T. F.; Robison, W. T.; Piker, C. W.; Gurnett, D. A.; Sampl, M.; Rucker, H. O.; Zarka, P.

    2012-09-01

    The Juno spacecraft was successfully launched on 5 August 2011 to begin its journey to Jupiter. With its arrival in the summer of 2016, the latest in a series of missions to Jupiter will begin. Juno will explore the origins of not only Jupiter, but also the solar system as a whole by understanding the interior of the planet and its atmospheric composition and dynamics. Juno will also be the first mission to explore Jupiter's polar magnetosphere and auroras. The Waves investigation is part of a suite of instruments which will contribute to this latter objective. Waves will measure wave electric fields in the frequency range from 50 Hz to 40 MHz and magnetic fields in the range of 50 Hz to 20 kHz to study radio and plasma waves in Jupiter's polar magnetosphere. Most importantly, Waves will contribute to understanding auroral processes at the giant planet via in situ observations of the sources of Jovian hectometric and decametric radiation as well as plasma waves which likely accelerate particles as part of the auroral process.

  4. A simple wave driver

    NASA Astrophysics Data System (ADS)

    Kağan Temiz, Burak; Yavuz, Ahmet

    2015-08-01

    This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the wheel starts to turn at a constant angular speed. A rod that is fixed on the wheel turns at the same constant angular speed, too. A tight string that the wave will be created on is placed at a distance where the rod can touch the string. During each rotation of the wheel, the rod vibrates the string up and down. The vibration frequency of this rod equals the wheel’s rotation frequency, and this frequency value can be measured easily with a small magnet and a bicycle speedometer. In this way, the frequency of the waves formed in the rope can also be measured.

  5. Ocean wave electric generators

    SciTech Connect

    Rosenberg, H.R.

    1986-02-04

    This patent describes an apparatus for generating electricity from ocean waves. It consists of: 1.) a hollow buoyant duck positioned in the path of waves including a core about the center axis of which the duck rotates, a lower chamber portion having liquid therein and an upper chamber portion having air therein. The air is alternately compressed and expanded by the liquid in the chamber during the rotational motion of the duck caused by waves. A turbine mounted in the upper portion of the duck is driven by the compressed and expanded air. A generator is coupled to the turbine and operated to produce electrical energy and an air bulb; 2.) a spine having a transverse axial shaft anchoring the spine to the ocean floor. The upper portion of the spine engages the duck to maintain the duck in position. The spine has a curved configuration to concentrate and direct wave energy. The spine configuration acts as a scoop to increase the height of wave peaks and as a foil to increase the depth of wave troughs.

  6. Rain waves-wind waves interaction application to scatterometry

    NASA Technical Reports Server (NTRS)

    Kharif, C.; Giovanangeli, J. P.; Bliven, L.

    1989-01-01

    Modulation of a rain wave pattern by longer waves has been studied. An analytical model taking into account capillarity effects and obliquity of short waves has been developed. Modulation rates in wave number and amplitude have been computed. Experiments were carried out in a wave tank. First results agree with theoretical models, but higher values of modulation rates are measured. These results could be taken into account for understanding the radar response from the sea surface during rain.

  7. Kinetic Alfvn waves in aurora.

    NASA Astrophysics Data System (ADS)

    Wang, Deyu

    1996-06-01

    On the basis of the differences between ideal MHD Alfvn waves and kinetic Alfvn waves, the nonlinear kinetic Alfvn wave with Poisson equation correction and the evolution of kinetic wave have been presented. These results have been used to explain the observation data from Freja satellite and CRIT II rocket in aurora.

  8. Lamb wave diffraction tomography

    NASA Astrophysics Data System (ADS)

    Malyarenko, Eugene Valentinovich

    As the worldwide aviation fleet continues to age, methods for accurately predicting the presence of structural flaws, such as hidden corrosion and disbonds, that compromise air worthiness become increasingly necessary. Ultrasonic guided waves, Lamb waves, allow large sections of aircraft structures to be rapidly inspected. However, extracting quantitative information from Lamb wave data has always involved highly trained personnel with a detailed knowledge of mechanical waveguide physics. In addition, human inspection process tends to be highly subjective, slow and prone to errors. The only practical alternative to traditional inspection routine is a software expert system capable of interpreting data with minimum error and maximum speed and reliability. Such a system would use the laws of guided wave propagation and material parameters to help signal processing algorithms automatically extract information from digitized waveforms. This work discusses several practical approaches to building such an expert system. The next step in the inspection process is data interpretation, and imaging is the most natural way to represent two-dimensional structures. Unlike conventional ultrasonic C-scan imaging that requires access to the whole inspected area, tomographic algorithms work with data collected over the perimeter of the sample. Combined with the ability of Lamb waves to travel over large distances, tomography becomes the method of choice for solving NDE problems. This work explores different tomographic reconstruction techniques to graphically represent the Lamb wave data in quantitative maps that can be easily interpreted by technicians. Because the velocity of Lamb waves depends on the thickness, the traveltimes of the fundamental modes can be converted into a thickness map of the inspected region. Lamb waves cannot penetrate through holes and other strongly scattering defects and the assumption of straight wave paths, essential for many tomographic algorithms, fails. Diffraction tomography is a way to incorporate scattering effects into tomographic algorithms in order to improve image quality and resolution. This work describes the iterative reconstruction procedure developed for the Lamb Wave tomography and allowing for ray bending correction for imaging of moderately scattering objects.

  9. O Wave-Wave Interactions on the Ocean Surface.

    NASA Astrophysics Data System (ADS)

    Naciri, Mamoun

    Part 1: Bragg scattering of sound from a line source by surface waves. The strong scattering of plane sound waves from a line source in a waveguide is analysed for a hard bottom and a soft undulatory surface representing one or two uniform surface waves. In the presence of one surface wave, sound is radiated and scattered in the same two directions. When two surface waves are present, each outgoing sound wave is scattered in two new directions in the horizontal plane. If the two surface waves satisfy one of two geometrical criteria, multiple scattering occurs and sound is resonantly scattered in a third new direction. Evolution equations are deduced for the sound wave envelopes, and the corresponding far field is asymptotically matched with the near field of the source. These envelopes are strongly dispersive and propagate in many directions. Part 2: Interactions of short and long waves on the sea surface. The evolution of a weakly nonlinear short wave interacting with a long gravity wave is investigated using a formulation based on Lagrangian variables. In Chapter I, the long wave is a weakly nonlinear irrotational Stokes wave. In Chapter II, we allow the long wave to assume a finite amplitude. Analytical results on the modulation of short waves agree fairly well with existing theories which rely on numerically obtained long waves. The evolution of short waves is described by a nonlinear Schrodinger equation with explicit time-periodic coefficients. Analysis of the stability of uniform short waves to sideband disturbances shows the appearance of additional bands of instability. Numerical results from both the nonlinear evolution and a lower order dynamical system suggest that the evolution of a uniform short wave disturbed by its most unstable sideband can become chaotic when the short wave slope increases and (or) when the long to short wave frequency ratio decreases. In Chapter III, the short waves are incident at an angle theta relative to the steep Gerstner wave. For small theta, the nonlinear evolution of the short wave envelope is described by a two-dimensional Schrodinger equation with explicit time-periodic coefficients. The Benjamin-Feir stability of uniform short waves to two-dimensional sidebands shows the proliferation of instability bands in addition to the single instability strip found in the absence of long waves. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253 -1690.) (Abstract shortened with permission of school.).

  10. Gravitational Wave Astronomy

    NASA Astrophysics Data System (ADS)

    Finn, Lee Samuel

    2012-03-01

    If two black holes collide in a vacuum, can they be observed? Until recently, the answer would have to be "no." After all, how would we observe them? Black holes are "naked" mass: pure mass, simple mass, mass devoid of any matter whose interactions might lead to the emission of photons or neutrinos, or any electromagnetic fields that might accelerate cosmic rays or leave some other signature that we could observe in our most sensitive astronomical instruments. Still, black holes do have mass. As such, they interactlike all massgravitationally. And the influence of gravity, like all influences, propagates no faster than that universal speed we first came to know as the speed of light. The effort to detect that propagating influence, which we term as gravitational radiation or gravitational waves, was initiated just over 50 years ago with the pioneering work of Joe Weber [1] and has been the object of increasingly intense experimental effort ever since. Have we, as yet, detected gravitational waves? The answer is still "no." Nevertheless, the accumulation of the experimental efforts begun fifty years ago has brought us to the point where we can confidently say that gravitational waves will soon be detected and, with that first detection, the era of gravitational wave astronomythe observational use of gravitational waves, emitted by heavenly bodieswill begin. Data analysis for gravitational wave astronomy is, today, in its infancy and its practitioners have much to learn from allied fields, including machine learning. Machine learning tools and techniques have not yet been applied in any extensive or substantial way to the study or analysis of gravitational wave data. It is fair to say that this owes principally to the fields relative youth and not to any intrinsic unsuitability of machine learning tools to the analysis problems the field faces. Indeed, the nature of many of the analysis problems faced by the field today cry-out for the application of machine learning techniques. My principal goal in this chapter is to (i) describe the gravitational wave astronomy problem domain and associated analysis challenges, and (ii) identify some specific problem areas where the application of machine learning techniques may be employed to particular advantage. In Section 19.2, I describe what gravitational waves are, how they are generated and propagated, and the several different observational technologies through which we expect, over the next decade or so, gravitational wave astronomy will exploit. I have written this section for the non astronomer; however, I think that even the gravitational wave astronomer may find the viewpoint taken here to be of interest. In Section 19.3, I deconstruct the work involved in the analysis of gravitational wave data and describe (briefly!) the techniques currently used for data analysis. The focus of Section 19.4 is on the application of machine learning tools and techniques in gravitational wave data analysis. I conclude with some closing remarks in Section 19.5.

  11. Longitudinal shear wave and transverse dilatational wave in solids.

    PubMed

    Catheline, S; Benech, N

    2015-02-01

    Dilatation wave involves compression and extension and is known as the curl-free solution of the elastodynamic equation. Shear wave on the contrary does not involve any change in volume and is the divergence-free solution. This letter seeks to examine the elastodynamic Green's function through this definition. By separating the Green's function in divergence-free and curl-free terms, it appears first that, strictly speaking, the longitudinal wave is not a pure dilatation wave and the transverse wave is neither a pure shear wave. Second, not only a longitudinal shear wave but also a transverse dilatational wave exists. These waves are shown to be a part of the solution known as coupling terms. Their special motion is carefully described and illustrated. PMID:25698051

  12. Optical Dark Rogue Wave

    PubMed Central

    Frisquet, Benoit; Kibler, Bertrand; Morin, Philippe; Baronio, Fabio; Conforti, Matteo; Millot, Guy; Wabnitz, Stefan

    2016-01-01

    Photonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena, and lead to novel space-time analogies, for example with multi-particle interactions. By injecting two colliding and modulated pumps with orthogonal states of polarization in a randomly birefringent telecommunication optical fiber, we provide the first experimental demonstration of an optical dark rogue wave. We also introduce the concept of multi-component analog gravity, whereby localized spatiotemporal horizons are associated with the dark rogue wave solution of the two-component nonlinear Schrödinger system. PMID:26864099

  13. Optical Dark Rogue Wave

    NASA Astrophysics Data System (ADS)

    Frisquet, Benoit; Kibler, Bertrand; Morin, Philippe; Baronio, Fabio; Conforti, Matteo; Millot, Guy; Wabnitz, Stefan

    2016-02-01

    Photonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena, and lead to novel space-time analogies, for example with multi-particle interactions. By injecting two colliding and modulated pumps with orthogonal states of polarization in a randomly birefringent telecommunication optical fiber, we provide the first experimental demonstration of an optical dark rogue wave. We also introduce the concept of multi-component analog gravity, whereby localized spatiotemporal horizons are associated with the dark rogue wave solution of the two-component nonlinear Schrödinger system.

  14. Vacuum Kundt waves

    NASA Astrophysics Data System (ADS)

    McNutt, David; Milson, Robert; Coley, Alan

    2013-03-01

    We discuss the invariant classification of vacuum Kundt waves using the Cartan-Karlhede algorithm and determine the upper bound on the number of iterations of the Karlhede algorithm to classify the vacuum Kundt waves (Collins (1991 Class. Quantum Grav. 8 1859-69), Machado Ramos (1996 Class. Quantum Grav. 13 1589)). By choosing a particular coordinate system we partially construct the canonical coframe used in the classification to study the functional dependence of the invariants arising at each iteration of the algorithm. We provide a new upper bound, q ⩽ 4, and show that this bound is sharp by analyzing the subclass of Kundt waves with invariant count beginning with (0, 1,…) to show that the class with invariant count (0, 1, 3, 4, 4) exists. This class of vacuum Kundt waves is shown to be unique as the only set of metrics requiring the fourth covariant derivatives of the curvature. We conclude with an invariant classification of the vacuum Kundt waves using a suite of invariants.

  15. Noise Driven Evolutionary Waves

    PubMed Central

    Hallatschek, Oskar

    2011-01-01

    Adaptation in spatially extended populations entails the propagation of evolutionary novelties across habitat ranges. Driven by natural selection, beneficial mutations sweep through the population in a “wave of advance”. The standard model for these traveling waves, due to R. Fisher and A. Kolmogorov, plays an important role in many scientific areas besides evolution, such as ecology, epidemiology, chemical kinetics, and recently even in particle physics. Here, we extend the Fisher–Kolmogorov model to account for mutations that confer an increase in the density of the population, for instance as a result of an improved metabolic efficiency. We show that these mutations invade by the action of random genetic drift, even if the mutations are slightly deleterious. The ensuing class of noise-driven waves are characterized by a wave speed that decreases with increasing population sizes, contrary to conventional Fisher–Kolmogorov waves. When a trade-off exists between density and growth rate, an evolutionary optimal population density can be predicted. Our simulations and analytical results show that genetic drift in conjunction with spatial structure promotes the economical use of limited resources. The simplicity of our model, which lacks any complex interactions between individuals, suggests that noise-induced pattern formation may arise in many complex biological systems including evolution. PMID:21423714

  16. Optical Dark Rogue Wave.

    PubMed

    Frisquet, Benoit; Kibler, Bertrand; Morin, Philippe; Baronio, Fabio; Conforti, Matteo; Millot, Guy; Wabnitz, Stefan

    2016-01-01

    Photonics enables to develop simple lab experiments that mimic water rogue wave generation phenomena, as well as relativistic gravitational effects such as event horizons, gravitational lensing and Hawking radiation. The basis for analog gravity experiments is light propagation through an effective moving medium obtained via the nonlinear response of the material. So far, analogue gravity kinematics was reproduced in scalar optical wave propagation test models. Multimode and spatiotemporal nonlinear interactions exhibit a rich spectrum of excitations, which may substantially expand the range of rogue wave phenomena, and lead to novel space-time analogies, for example with multi-particle interactions. By injecting two colliding and modulated pumps with orthogonal states of polarization in a randomly birefringent telecommunication optical fiber, we provide the first experimental demonstration of an optical dark rogue wave. We also introduce the concept of multi-component analog gravity, whereby localized spatiotemporal horizons are associated with the dark rogue wave solution of the two-component nonlinear Schrödinger system. PMID:26864099

  17. Pilot-Wave Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Bush, John W. M.

    2015-01-01

    Yves Couder, Emmanuel Fort, and coworkers recently discovered that a millimetric droplet sustained on the surface of a vibrating fluid bath may self-propel through a resonant interaction with its own wave field. This article reviews experimental evidence indicating that the walking droplets exhibit certain features previously thought to be exclusive to the microscopic, quantum realm. It then reviews theoretical descriptions of this hydrodynamic pilot-wave system that yield insight into the origins of its quantum-like behavior. Quantization arises from the dynamic constraint imposed on the droplet by its pilot-wave field, and multimodal statistics appear to be a feature of chaotic pilot-wave dynamics. I attempt to assess the potential and limitations of this hydrodynamic system as a quantum analog. This fluid system is compared to quantum pilot-wave theories, shown to be markedly different from Bohmian mechanics and more closely related to de Broglie's original conception of quantum dynamics, his double-solution theory, and its relatively recent extensions through researchers in stochastic electrodynamics.

  18. Waves in Motion

    NASA Astrophysics Data System (ADS)

    McGourty, L.; Rideout, K.

    2005-12-01

    "Waves in Motion" This teaching unit was created by Leslie McGourty and Ken Rideout under the Research Experience for Teachers (RET) program at MIT Haystack Observatory during the summer of 2005. The RET program is funded by a grant from the National Science Foundation. The goals of this teaching unit are to deepen students' understanding about waves, wave motion, and the electromagnetic spectrum as a whole. Specifically students will comprehend the role radio waves play in our daily lives and in the investigation of the universe. The lessons can be used in a high school physics, earth science or astronomy curriculum. The unit consists of a series of interlocking lectures, activities, and investigations that can be used as stand alone units to supplement a teacher's existing curriculum, as an independent investigation for a student, or as a long exploration into radio astronomy with a theme of waves in space: how and where they carry their information. Special emphasis is given to the Relativity theories in honor of the "World Year of Physics" to celebrate Einstein's 1905 contributions. The lessons are currently being implemented at the high school level, the preliminary results of which will be presented. At the end of the academic year, the units will be evaluated and updated, reflecting student input and peer review after which they will be posted on the internet for teachers to use in their classrooms.

  19. Potential changes of wave steepness and occurrence of rogue waves

    NASA Astrophysics Data System (ADS)

    Bitner-Gregersen, Elzbieta M.; Toffoli, Alessandro

    2015-04-01

    Wave steepness is an important characteristic of a sea state. It is also well established that wave steepness is one of the parameter responsible for generation of abnormal waves called also freak or rogue waves. The study investigates changes of wave steepness in the past and future wave climate in the North Atlantic. The fifth assessment report IPCC (2013) uses four scenarios for future greenhouse gas concentrations in the atmosphere called Representative Concentration Pathways (RCP). Two of these scenarios RCP 4.5 and RCP 8.5 have been selected to project future wave conditions in the North Atlantic. RCP 4.5 is believed to achieve the political target of a maximum global mean temperature increase of 2° C while RPC 8.5 is close to 'business as usual' and expected to give a temperature increase of 4° C or more. The analysis includes total sea, wind sea and swell. Potential changes of wave steepness for these wave systems are shown and compared with wave steepness derived from historical data. Three historical data sets with different wave model resolutions are used. The investigations show also changes in the mean wind direction as well as in the relative direction between wind sea and swell. Consequences of wave steepness changes for statistics of surface elevation and generation of rogue waves are demonstrated. Uncertainties associated with wave steepness projections are discussed.

  20. Tango waves in a bidomain model of fertilization calcium waves

    NASA Astrophysics Data System (ADS)

    Li, Yue-Xian

    2003-12-01

    Fertilization of an egg cell is marked by one or several Ca 2+ waves that travel across the intra-cellular space, called fertilization Ca 2+ waves. Patterns of Ca 2+ waves observed in mature or immature oocytes include traveling fronts and pulses as well as concentric and spiral waves. These patterns have been studied in other excitable media in physical, chemical, and biological systems. Here, we report the discovery of a new wave phenomenon in the numerical study of a bidomain model of fertilization Ca 2+ waves. This wave is a front that propagates in a back-and-forth manner that resembles the movement of tango dancers, thus is called a tango wave. When the medium is excitable, a forward-moving tango wave can generate traveling pulses that propagate down the space without reversal. The study shows that the occurrence of tango waves is related to spatial inhomogeneity in the local dynamics. This is tested and confirmed by simulating similar waves in a medium with stationary spatial inhomogeneity. Similar waves are also obtained in a FitzHugh-Nagumo system with a linear spatial ramp. In both the bidomain model of Ca 2+ waves and the FitzHugh-Nagumo system, the front is stable when the slope of a linear ramp is large. As the slope decreases beyond a critical value, front oscillations occur. The study shows that tango waves facilitate the dispersion of localized Ca 2+. Key features of the bidomain model underlying the occurrence of tango waves are revealed. These features are commonly found in egg cells of a variety of species. Thus, we predict that tango waves can occur in real egg cells provided that a slowly varying inhomogeneity does occur following the sperm entry. The observation of tango wave-like waves in nemertean worm and ascidian eggs seems to support such a prediction.

  1. Neural field theory of nonlinear wave-wave and wave-neuron processes

    NASA Astrophysics Data System (ADS)

    Robinson, P. A.; Roy, N.

    2015-06-01

    Systematic expansion of neural field theory equations in terms of nonlinear response functions is carried out to enable a wide variety of nonlinear wave-wave and wave-neuron processes to be treated systematically in systems involving multiple neural populations. The results are illustrated by analyzing second-harmonic generation, and they can also be applied to wave-wave coalescence, multiharmonic generation, facilitation, depression, refractoriness, and other nonlinear processes.

  2. IR Hot Wave

    SciTech Connect

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  3. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  4. Traveling wave tube circuit

    NASA Technical Reports Server (NTRS)

    Connolly, D. J. (Inventor)

    1978-01-01

    A traveling wave tube (TWT) has a slow wave structure (SWS) which is severed into two or more sections. A signal path, connects the end of an SWS section to the beginning of the following SWS section. The signal path comprises an impedance matching coupler (IMC), followed by an isolator, a variable phase shifter, and a second IMC. The aggregate band pass characteristic of the components in the signal path is chosen to reject, or strongly attenuate, all frequencies outside the desired operating frequency range of the TWT and yet pass, with minimal attenuation in the forward direction, all frequencies within the desired operating frequency range. The isolator is chosen to reject, or strongly attenuate, waves, of all frequencies, which propagate in the backward direction. The aggregate phase shift characteristic of the components in the signal path is chosen to apply signal power to the beginning of the following SWS section with the phase angle yielding maximum efficiency.

  5. Planetary radio waves

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1986-01-01

    Three planets, the earth, Jupiter and Saturn are known to emit nonthermal radio waves which require coherent radiation processes. The characteristic features (frequency spectrum, polarization, occurrence probability, radiation pattern) are discussed. Radiation which is externally controlled by the solar wind is distinguished from internally controlled radiation which only originates from Jupiter. The efficiency of the externally controlled radiation is roughly the same at all three planets (5 x 10 to the -6th) suggesting that similar processes are active there. The maser radiation mechanism for the generation of the radio waves and general requirements for the mechanism which couples the power generator to the region where the radio waves are generated are briefly discussed.

  6. Miniature plasmonic wave plates.

    PubMed

    Drezet, Aurélien; Genet, Cyriaque; Ebbesen, Thomas W

    2008-07-25

    Linear birefringence, as implemented in wave plates, is a natural way to control the state of polarization of light. We report on a general method for designing miniature planar wave plates using surface plasmons. The resonant optical device considered here is a single circular aperture surrounded by an elliptical antenna grating. The difference between the short and long axis of each ellipsis introduces a phase shift on the surface plasmons which enables the realization of a quarter wave plate. Furthermore, the experimental results and the theoretical analysis show that the general procedure used does not influence the optical coherence of the polarization state and allows us to explore completely the surface of the unit Poincaré sphere by changing only the shape of the elliptical grating. PMID:18764329

  7. Solar system plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1995-01-01

    An overview is given of spacecraft observations of plasma waves in the solar system. In situ measurements of plasma phenomena have now been obtained at all of the planets except Mercury and Pluto, and in the interplanetary medium at heliocentric radial distances ranging from 0.29 to 58 AU. To illustrate the range of phenomena involved, we discuss plasma waves in three regions of physical interest: (1) planetary radiation belts, (2) planetary auroral acceleration regions and (3) the solar wind. In each region we describe examples of plasma waves that are of some importance, either due to the role they play in determining the physical properties of the plasma, or to the unique mechanism involved in their generation.

  8. Upstream waves at Mars

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Luhmann, J. G.; Schwingenschuh, K.; Riedler, W.; Eroshenko, E.

    1992-01-01

    Weak, about 0.15 nT, narrow band emissions at the proton gyro frequency are observed by the Phobos magnetometer MAGMA, upstream from the bow shock of Mars. These waves are left-hand elliptically polarized. They may be associated with the pick up of protons from the Martian hydrogen exosphere. Strong turbulence, similar to that observed at the terrestrial bow shock, is found on occasion in the upstream region when the IMF connects to the bow shock. On two occasions this turbulence occurred when the spacecraft crossed the orbit of Phobos. This coincidence raises the possibility that material in the orbits of Phobos interacts with the solar wind in such a way to either affect the direction of the IMF or to cause instabilities in the solar wind plasma. However, since on a third occasion these waves did not occur, these waves may be shock associated rather than Phobos associated.

  9. The gravitational wave experiment

    NASA Technical Reports Server (NTRS)

    Bertotti, B.; Ambrosini, R.; Asmar, S. W.; Brenkle, J. P.; Comoretto, G.; Giampieri, G.; Less, L.; Messeri, A.; Wahlquist, H. D.

    1992-01-01

    Since the optimum size of a gravitational wave detector is the wave length, interplanetary dimensions are needed for the mHz band of interest. Doppler tracking of Ulysses will provide the most sensitive attempt to date at the detection of gravitational waves in the low frequency band. The driving noise source is the fluctuations in the refractive index of interplanetary plasma. This dictates the timing of the experiment to be near solar opposition and sets the target accuracy for the fractional frequency change at 3.0 x 10 exp -14 for integration times of the order of 1000 sec. The instrumentation utilized by the experiment is distributed between the radio systems on the spacecraft and the seven participating ground stations of the Deep Space Network and Medicina. Preliminary analysis is available of the measurements taken during the Ulysses first opposition test.

  10. Electromagnetic wave test

    NASA Astrophysics Data System (ADS)

    Matthews, R. K.; Stepanek, S. A.

    Electromagnetic wave testing, which represents a relatively new test technique that involves the union of several disciplines (aerothermodynamics, electromagnetics, materials/structures, and advanced diagnostics) is introduced. The essence of this new technique deals with the transmission and possible distortion of electromagnetic waves (RF or IR) as they pass through the bow shock, flow field, and electromagnetic window of a missile flying at hypersonic speeds. Variations in gas density along the optical path can cause significant distortion of the electromagnetic waves and, therefore the missile seeker system may not effectively track the target. Two specific test techniques are described. The first example deals with the combining of a wind tunnel and an RF range while the second example discusses the complexities of evaluating IR seeker system performance.

  11. Human waves in stadiums

    NASA Astrophysics Data System (ADS)

    Farkas, I.; Helbing, D.; Vicsek, T.

    2003-12-01

    Mexican wave first widely broadcasted during the 1986 World Cup held in Mexico, is a human wave moving along the stands of stadiums as one section of spectators stands up, arms lifting, then sits down as the next section does the same. Here we use variants of models originally developed for the description of excitable media to demonstrate that this collective human behaviour can be quantitatively interpreted by methods of statistical physics. Adequate modelling of reactions to triggering attempts provides a deeper insight into the mechanisms by which a crowd can be stimulated to execute a particular pattern of behaviour and represents a possible tool of control during events involving excited groups of people. Interactive simulations, video recordings and further images are available at the webpage dedicated to this work: http://angel.elte.hu/wave.

  12. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2001-07-17

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  13. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2003-02-11

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase-shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in the direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  14. TIMING OF SHOCK WAVES

    DOEpatents

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  15. Solitary waves of the equal width wave equation

    NASA Astrophysics Data System (ADS)

    Gardner, L. R. T.; Gardner, G. A.

    1992-07-01

    The migration and interaction of solitary waves are presently simulated by means of a numerical solution of the equal-width wave equation using Galerkin method-based cubic B-spline finite elements. It is noted that when the amplitudes of the two interacting waves are equal and opposite, the resulting solitary-wave source generates trains of solitary waves whose amplitudes are of the order of the amplitudes of the initiating waves. After evaluating the three invariants of the motion to ascertain system conservation properties, attention is given to the temporal evolution of a Maxwellian initial pulse.

  16. Adaptive multiconfigurational wave functions

    SciTech Connect

    Evangelista, Francesco A.

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff Λ. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than Λ. The resulting Λ-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (Λ+SD-CI), which is based on a small Λ-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build Λ-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The Λ-CI and Λ+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the Λ-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the Λ-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  17. Explosive plane-wave lens

    DOEpatents

    Marsh, S.P.

    1988-03-08

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 4 figs.

  18. Explosive plane-wave lens

    DOEpatents

    Marsh, S.P.

    1987-03-12

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 3 figs., 3 tabs.

  19. The Virtual Wave Observatory (VWO)

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.

    2008-01-01

    Heliophysics wave data are currently not easily searchable by computers, making identifying pertinent wave data features for analyses and cross comparisons difficult and laborious. Since wave data analysis requires specialized knowledge about waves, which spans the spectrum of microphysics to macrophysics, researchers having varied expertise cannot easily use wave data. To resolve these difficulties and to allow wave data to contribute more fully to Heliophysics research, we are developing a Virtual Wave Observatory (VWO) whose goal is to enable all Heliophysics wave data to become searchable, understandable and usable by the Heliophysics community. The VWO objective is to enable search of multiple and distributed wave data (from both active and passive measurements). This presentation provides and overview of the VWO, a new VxO component within the emerging distributed Heliophysics data and model environment.

  20. Explosive plane-wave lens

    DOEpatents

    Marsh, Stanley P.

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  1. Wave Turbulence on Water Surface

    NASA Astrophysics Data System (ADS)

    Nazarenko, Sergey; Lukaschuk, Sergei

    2016-03-01

    We overview the wave turbulence approach by example of one physical system: gravity waves on the surface of an infinitely deep fluid. In the theoretical part of our review, we derive the nonlinear Hamiltonian equations governing the water-wave system and describe the premises of the weak wave turbulence theory. We outline derivation of the wave-kinetic equation and the equation for the probability density function, and most important solutions to these equations, including the Kolmogorov-Zakharov spectra corresponding to a direct and an inverse turbulent cascades, as well as solutions for non-Gaussian wave fields corresponding to intermittency. We also discuss strong wave turbulence as well as coherent structures and their interaction with random waves. We describe numerical and laboratory experiments, and field observations of gravity wave turbulence, and compare their results with theoretical predictions.

  2. RADIATION WAVE DETECTOR

    DOEpatents

    Wouters, L.F.

    1958-10-28

    The detection of the shape and amplitude of a radiation wave is discussed, particularly an apparatus for automatically indicating at spaced lntervals of time the radiation intensity at a flxed point as a measure of a radiation wave passing the point. The apparatus utilizes a number of photomultiplier tubes surrounding a scintillation type detector, For obtainlng time spaced signals proportional to radiation at predetermined intervals the photolnultiplier tubes are actuated ln sequence following detector incidence of a predetermined radiation level by electronic means. The time spaced signals so produced are then separately amplified and relayed to recording means.

  3. Nondispersing Bohr Wave Packets

    SciTech Connect

    Maeda, H.; Gurian, J. H.; Gallagher, T. F.

    2009-03-13

    Long-lived, nondispersing circular, or Bohr, wave packets are produced starting from Li Rydberg atoms by exposing them first to a linearly polarized microwave field at the orbital frequency, 17.6 GHz at principal quantum number n=72, which locks the electron's motion into an approximately linear orbit in which the electron oscillates in phase with the microwave field. The microwave polarization is changed to circular polarization slowly compared to the orbital frequency, and the electron's motion follows, resulting in a nondispersing Bohr wave packet.

  4. Nondispersing Bohr Wave Packets

    NASA Astrophysics Data System (ADS)

    Maeda, H.; Gurian, J. H.; Gallagher, T. F.

    2009-03-01

    Long-lived, nondispersing circular, or Bohr, wave packets are produced starting from Li Rydberg atoms by exposing them first to a linearly polarized microwave field at the orbital frequency, 17.6 GHz at principal quantum number n=72, which locks the electron’s motion into an approximately linear orbit in which the electron oscillates in phase with the microwave field. The microwave polarization is changed to circular polarization slowly compared to the orbital frequency, and the electron’s motion follows, resulting in a nondispersing Bohr wave packet.

  5. Quantum positron acoustic waves

    SciTech Connect

    Metref, Hassina; Tribeche, Mouloud

    2014-12-15

    Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.

  6. THERMOPLASTIC WAVES IN MAGNETARS

    SciTech Connect

    Beloborodov, Andrei M.; Levin, Yuri E-mail: yuri.levin@monash.edu.au

    2014-10-20

    Magnetar activity is generated by shear motions of the neutron star surface, which relieve internal magnetic stresses. An analogy with earthquakes and faults is problematic, as the crust is permeated by strong magnetic fields which greatly constrain crustal displacements. We describe a new deformation mechanism that is specific to strongly magnetized neutron stars. The magnetically stressed crust begins to move because of a thermoplastic instability, which launches a wave that shears the crust and burns its magnetic energy. The propagating wave front resembles the deflagration front in combustion physics. We describe the conditions for the instability, the front structure, and velocity, and discuss implications for observed magnetar activity.

  7. Thermoplastic Waves in Magnetars

    NASA Astrophysics Data System (ADS)

    Beloborodov, Andrei M.; Levin, Yuri

    2014-10-01

    Magnetar activity is generated by shear motions of the neutron star surface, which relieve internal magnetic stresses. An analogy with earthquakes and faults is problematic, as the crust is permeated by strong magnetic fields which greatly constrain crustal displacements. We describe a new deformation mechanism that is specific to strongly magnetized neutron stars. The magnetically stressed crust begins to move because of a thermoplastic instability, which launches a wave that shears the crust and burns its magnetic energy. The propagating wave front resembles the deflagration front in combustion physics. We describe the conditions for the instability, the front structure, and velocity, and discuss implications for observed magnetar activity.

  8. Wave Motion Electric Generator

    SciTech Connect

    Jacobi, E. F.; Winkler, R. J.

    1983-12-27

    Set out herein is an electrical generator conformed for installation in a buoy, the generator comprising an inverted pendulum having two windings formed at the free end thereof and aligned to articulate between two end stops each provided with a magnetic circuit. As the loops thus pass through the magnetic circuit, electrical current is induced which may be rectified through a full way rectifier to charge up a storage battery. The buoy itself may be ballasted to have its fundamental resonance at more than double the wave frequency with the result that during each passing of a wave at least two induction cycles occur.

  9. Quantum wave turbulence

    NASA Astrophysics Data System (ADS)

    Haeri, M. B.; Putterman, S. J.; Garcia, A.; Roberts, P. H.

    1993-01-01

    The nonlinear quantum kinetic equation for the interaction of sound waves is solved via analytic and numerical techniques. In the classical regime energy cascades to higher frequency (ω) according to the steady-state power law ω-3/2. In the quantum limit, the system prefers a reverse cascade of energy which follows the power law ω-6. Above a critical flux, a new type of spectrum appears which is neither self-similar nor close to equilibrium. This state of nonlinear quantum wave turbulence represents a flow of energy directly from the classical source to the quantum degrees of freedom.

  10. Ultrasonic shear wave couplant

    DOEpatents

    Kupperman, David S.; Lanham, Ronald N.

    1985-01-01

    Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

  11. Ultrasonic shear wave couplant

    DOEpatents

    Kupperman, D.S.; Lanham, R.N.

    1984-04-11

    Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

  12. Do urologists follow the golden rule? A global urolithiasis management study by the Clinical Research Office of the Endourological Society

    PubMed Central

    Roberts, Gregory; Opondo, Dedan; Nott, Linda; Razvi, Hassan; de la Rosette, Jean; Beiko, Darren

    2016-01-01

    Introduction: The primary objective of this study was to compare surgical management options for various urolithiasis scenarios that urologists would choose for themselves vs. the options they would recommend for their patients. The secondary objective was to identify the common recommended treatments for upper urinary tract stones of various sizes and locations. Methods: Two surveys were sent by the Clinical Research Office of the Endourological Society (CROES) to members of the Endourological Society. Standard demographic information was collected. The first survey asked the urologists to recommend treatment for urolithiasis in 10 different scenarios assuming that they were the patient with stone disease. The second survey, sent eight months later, asked urologists to recommend treatment for the same 10 scenarios for a theoretical patient. Only urologists who responded to the first and the second survey were included. Recommended treatment options were compared between the surveys. Agreement between the two scenarios was measured with Cohen’s kappa. Surveys were conducted on the Internet using SurveyMonkey™. All statistical analyses were performed using R statistical program version 2.12.2. Results: The two surveys had response rates of 78% (160/205) and 84% (172/205), respectively with urologists from 38 countries. Median experience of respondents was seven years (range: 2–30). The majority of respondents, 117 (75%), were affiliated with academic hospitals. Recommended treatments for stone disease in different scenarios were not entirely consistent when the urologists considered themselves as the patients compared to the choice they might recommend for their patients. Cohen’s kappa ranged from 0.292–0.534 for the different scenarios. Overall, shock wave lithotripsy (SWL) and ureteroscopy (URS) were the most commonly chosen treatment options, with medical expulsive therapy (MET) and laparoscopy being the least recommended by urologists for themselves, as well as for their patients. Conclusions: Although urologists were not entirely consistent in their recommendations for stone treatment, they generally followed the “golden rule” and treated their patients as they would want to be treated. The most commonly recommended treatments for upper urinary tract stones were SWL and URS. PMID:26977207

  13. Wave Tank Studies of Phase Velocities of Short Wind Waves

    NASA Astrophysics Data System (ADS)

    Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

    Wave tank studies of phase velocities of short wind waves have been carried out using Ka-band radar and an Optical Spectrum Analyser. The phase velocities were retrieved from measured radar and optical Doppler shifts, taking into account measurements of surface drift velocities. The dispersion relationship was studied in centimetre (cm)- and millimetre(mm)-scale wavelength ranges at different fetches and wind speeds, both for a clean water surface and for water covered with surfactant films. It is ob- tained that the phase velocities do not follow the dispersion relation of linear capillary- gravity waves, increasing with fetch and, therefore, depending on phase velocities of dominant decimetre (dm)-centimetre-scale wind waves. One thus can conclude that nonlinear cm-mm-scale harmonics bound to the dominant wind waves and propagat- ing with the phase velocities of the decimetric waves are present in the wind wave spectrum. The resulting phase velocities of short wind waves are determined by re- lation between free and bound waves. The relative intensity of the bound waves in the spectrum of short wind waves is estimated. It is shown that this relation depends strongly on the surfactant concentration, because the damping effect due to films is different for free and bound waves; this results to changes of phase velocities of wind waves in the presence of surfactant films. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

  14. The role of Biot slow waves in electroseismic wave phenomena.

    PubMed

    Pride, Steven R; Garambois, Stéphane

    2002-02-01

    The electromagnetic fields that are generated as a spherical seismic wave (either P or S) traverses an interface separating two porous materials are numerically modeled both with and without the generation of Biot slow waves at the interface. In the case of an incident fast-P wave, the predicted electric-field amplitudes when slow waves are neglected can easily be off by as much as an order of magnitude. In the case of an incident S wave, the error is much smaller (typically on the order of 10% or less) because not much S-wave energy gets converted into slow waves. In neglecting the slow waves, only six plane waves (reflected and transmitted fast-P, S, and EM waves) are available with which to match the eight continuity conditions that hold at each interface. This overdetermined problem is solved by placing weights on the eight continuity conditions so that those conditions that are most important for obtaining the proper response are emphasized. It is demonstrated that when slow waves are neglected, it is best to also neglect the continuity of the Darcy flow and fluid pressure across an interface. The principal conclusion of this work is that to properly model the electromagnetic (EM) fields generated at an interface by an incident seismic wave, the full Biot theory that allows for generation of slow waves must be employed. PMID:11863172

  15. Continuous-wave Submillimeter-wave Gyrotrons

    PubMed Central

    Han, Seong-Tae; Griffin, Robert G.; Hu, Kan-Nian; Joo, Chan-Gyu; Joye, Colin D.; Mastovsky, Ivan; Shapiro, Michael A.; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Torrezan, Antonio C.; Woskov, Paul P.

    2007-01-01

    Recently, dynamic nuclear polarization enhanced nuclear magnetic resonance (DNP/NMR) has emerged as a powerful technique to obtain significant enhancements in spin spectra from biological samples. For DNP in modern NMR systems, a high power continuous-wave source in the submillimeter wavelength range is necessary. Gyrotrons can deliver tens of watts of CW power at submillimeter wavelengths and are well suited for use in DNP/NMR spectrometers. To date, 140 GHz and 250 GHz gyrotrons are being employed in DNP spectrometer experiments at 200 MHz and 380 MHz at MIT. A 460 GHz gyrotron, which has operated with 8 W of CW output power, will soon be installed in a 700 MHz NMR spectrometer. High power radiation with good spectral and spatial resolution from these gyrotrons should provide NMR spectrometers with high signal enhancement through DNP. Also, these tubes operating at submillimeter wavelengths should have important applications in research in physics, chemistry, biology, materials science and medicine. PMID:17404605

  16. Oblique dust density waves

    NASA Astrophysics Data System (ADS)

    Piel, Alexander; Arp, Oliver; Menzel, Kristoffer; Klindworth, Markus

    2007-11-01

    We report on experimental observations of dust density waves in a complex (dusty) plasma under microgravity. The plasma is produced in a radio-frequency parallel-plate discharge (argon, p=15Pa, U=65Vpp). Different sizes of dust particles were used (3.4 μm and 6.4μm diameter). The low-frequency (f 11Hz) dust density waves are naturally unstable modes, which are driven by the ion flow in the plasma. Surprisingly, the wave propagation direction is aligned with the ion flow direction in the bulk plasma but becomes oblique at the boundary of the dust cloud with an inclination of 60^o with respect to the plasma boundary. The experimental results are compared with a kinetic model in the electrostatic approximation [1] and a fluid model [2]. Moreover, the role of dust surface waves is discussed. [1] M. Rosenberg, J. Vac. Sci. Technol. A 14, 631 (1996) [2] A. Piel et al, Phys. Rev. Lett. 97, 205009 (2006)

  17. Submillimeter wave heterodyne receiver

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam (Inventor); Manohara, Harish (Inventor); Siegel, Peter H. (Inventor); Ward, John (Inventor)

    2011-01-01

    In an embodiment, a submillimeter wave heterodyne receiver includes a finline ortho-mode transducer comprising thin tapered metallic fins deposited on a thin dielectric substrate to separate a vertically polarized electromagnetic mode from a horizontally polarized electromagnetic mode. Other embodiments are described and claimed.

  18. Radiative Blast Waves

    NASA Astrophysics Data System (ADS)

    Keilty, K. A.; Liang, E. P.; Ditmire, T.; Remington, B. A.

    2001-04-01

    We simulate experiments performed with the Falcon laser at Lawrence Livermore National Laboratory to generate strong blast waves expanding in cylindrical geometry of relevance to astrophysics. In particular, we are interested in producing and modeling radiative shocks. Our goal is to develop a laboratory setting for studying radiative shocks of relevance to supernova remnants. In previous work we have demonstrated that it is possible to generate radiative shocks in the laboratory. In additions, we have shown how we can determine the energy-loss rate of the shock from the blast wave evolution using a simple analytic method that is independent of the details of radiative cooling and is scalable to both the laboratory and astrophysical blast waves. Our current work deals with instabilities associated with radiative blast waves and their application to the laboratory and to astrophysics. We examine some of the previous work done in the area of radiative instabilities in supernova remnants and discuss the challenges of adapting this work to the laboratory setting.

  19. Waves: Internal Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    1999-01-01

    Oceanic internal tides are internal waves with tidal periodicities. They are ubiquitous throughout the ocean, although generally more pronounced near large bathymetric features such as mid-ocean ridges and continental slopes. The internal vertical displacements associated with these waves can be extraordinarily large. Near some shelf breaks where the surface tides are strong, internal displacements (e.g., of an isothermal surface) can exceed 200 meters. Displacements of 10 meters in the open ocean are not uncommon. The associated current velocities are usually comparable to or larger than the currents of the surface tide. On continental shelves internal tides can occasionally generate packets of internal solitons, which are detectable in remote sensing imagery. Other common nonlinear features are generation of higher harmonics (e.g., 6-hr waves) and wave breaking. Internal tides are known to be an important energy source for mixing of shelf waters. Recent research suggests that they may also be a significant energy source for deep-ocean mixing.

  20. "Hearing" Electromagnetic Waves

    ERIC Educational Resources Information Center

    Rojo, Marta; Munoz, Juan

    2014-01-01

    In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic…

  1. Waves on Ice

    Atmospheric Science Data Center

    2013-04-16

    article title:  Waves on White: Ice or Clouds?     View ... captured this image showing a wavy pattern in a field of white. At most other latitudes, such wavy patterns would likely indicate ... are yellow; dark blue shows confidently clear areas, while light blue indicates clear with lower confidence. The ASCM works particularly ...

  2. Deflagration Wave Profiles

    SciTech Connect

    Menikoff, Ralph

    2012-04-03

    Shock initiation in a plastic-bonded explosives (PBX) is due to hot spots. Current reactive burn models are based, at least heuristically, on the ignition and growth concept. The ignition phase occurs when a small localized region of high temperature (or hot spot) burns on a fast time scale. This is followed by a growth phase in which a reactive front spreads out from the hot spot. Propagating reactive fronts are deflagration waves. A key question is the deflagration speed in a PBX compressed and heated by a shock wave that generated the hot spot. Here, the ODEs for a steady deflagration wave profile in a compressible fluid are derived, along with the needed thermodynamic quantities of realistic equations of state corresponding to the reactants and products of a PBX. The properties of the wave profile equations are analyzed and an algorithm is derived for computing the deflagration speed. As an illustrative example, the algorithm is applied to compute the deflagration speed in shock compressed PBX 9501 as a function of shock pressure. The calculated deflagration speed, even at the CJ pressure, is low compared to the detonation speed. The implication of this are briefly discussed.

  3. Oblique detonation wave ramjet

    NASA Technical Reports Server (NTRS)

    Morrison, R. B.

    1980-01-01

    Two conceptual designs of the oblique detonation wave ramjet are presented. The performance is evaluated for stoichiometric hydrogen-air equivalence ratios of phi = 1/3, 2/3 and 1 for a range of flight Mach numbers from 6 to 10.

  4. Cold wave lotion poisoning

    MedlinePlus

    ... and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call ... forms that need to be diluted before use. Exposure to concentrated cold wave lotion will cause much more damage than over-the-counter lotion.

  5. "Hearing" Electromagnetic Waves

    ERIC Educational Resources Information Center

    Rojo, Marta; Munoz, Juan

    2014-01-01

    In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic

  6. Twisting Neutron Waves

    NASA Astrophysics Data System (ADS)

    Pushin, Dmitry

    Most waves encountered in nature can be given a ``twist'', so that their phase winds around an axis parallel to the direction of wave propagation. Such waves are said to possess orbital angular momentum (OAM). For quantum particles such as photons, atoms, and electrons, this corresponds to the particle wavefunction having angular momentum of Lℏ along its propagation axis. Controlled generation and detection of OAM states of photons began in the 1990s, sparking considerable interest in applications of OAM in light and matter waves. OAM states of photons have found diverse applications such as broadband data multiplexing, massive quantum entanglement, optical trapping, microscopy, quantum state determination and teleportation, and interferometry. OAM states of electron beams have been used to rotate nanoparticles, determine the chirality of crystals and for magnetic microscopy. Here I discuss the first demonstration of OAM control of neutrons. Using neutron interferometry with a spatially incoherent input beam, we show the addition and conservation of quantum angular momenta, entanglement between quantum path and OAM degrees of freedom. Neutron-based quantum information science heretofore limited to spin, path, and energy degrees of freedom, now has access to another quantized variable, and OAM modalities of light, x-ray, and electron beams are extended to a massive, penetrating neutral particle. The methods of neutron phase imprinting demonstrated here expand the toolbox available for development of phase-sensitive techniques of neutron imaging. Financial support provided by the NSERC Create and Discovery programs, CERC and the NIST Quantum Information Program is acknowledged.

  7. Waves and Water Beetles

    ERIC Educational Resources Information Center

    Tucker, Vance A.

    1971-01-01

    Capillary and gravity water waves are related to the position, wavelength, and velocity of an object in flowing water. Water patterns are presented for ships and the whirling beetle with an explanation of how the design affects the objects velocity and the observed water wavelengths. (DS)

  8. Diraclike relativistic wave equation

    NASA Astrophysics Data System (ADS)

    Pletyukhov, V. A.; Strazhev, V. I.

    1983-12-01

    It is proved that nondissociating P-invariant relativistic wave equations (RWE) for particles with maximal spin so whose matrices satisfy the commutative relations of Dirac matrix algebra contain all values of the spin from 0 (1/2) to so. Corollaries of the theorem are examined for certain of the existing approaches to the construction of a theory of RWE.

  9. Search for Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Pizzella, G.

    2002-06-01

    Gravitational waves and their possible astrophysical sources are reviewed. The experiments in the data taking stage or in preparation, with resonant and non resonant detectors, are briefly outlined. Results obtained with the resonant detectors ALLEGRO, AURIGA, EXPLORER, NAUTILUS and NIOBE are given at a sensitivity level of h ~ 4 10-19. Perspectives are indicated.

  10. Oscilloscope Traveling Wave Experiment.

    ERIC Educational Resources Information Center

    Cloud, S. D.

    1985-01-01

    The moving pattern that appears on an oscilloscope screen is used to illustrate two kinds of wave motion and the relationship between them. Suggestions are presented for measuring wavelength, frequency, phase shift, and phase velocity in this college-level laboratory exercise. (DH)

  11. Waves and Crops

    ERIC Educational Resources Information Center

    Bennett, J.

    1973-01-01

    Discusses wave patterns on the surfaces of ripening wheat and barley crops when the wind is moderately strong. Examines the structure of the turbulence over such natural surfaces and conditions under which the crop may be damaged by the wind. (JR)

  12. Generating electromagnetic waves from gravity waves in cosmology

    SciTech Connect

    Hogan, P. A.; O'Farrell, S.

    2009-05-15

    Examples of test electromagnetic waves on a Friedmann-Lemaitre-Robertson-Walker (FLRW) background are constructed from explicit perturbations of the FLRW space-times describing gravitational waves propagating in the isotropic universes. A possible physical mechanism for the production of the test electromagnetic waves is shown to be the coupling of the gravitational waves with a test magnetic field, confirming the observation of Marklund, Dunsby and Brodin [Phys. Rev. D 62, 101501(R) (2000)].

  13. Freak waves under typhoon conditions

    NASA Astrophysics Data System (ADS)

    Mori, Nobuhito

    2012-11-01

    Benjamin-Feir Index (BFI) and directional spread are measures of nonlinear four-wave interactions and resultant indices of possible conditions for freak waves. Temporal-spatial distributions of BFI and directional spread are examined with numerical simulations of a spectral wave model using typhoon conditions. The spatial distributions of wave characteristics such as significant wave height, wave period, BFI and directional spread are different from each other around the eye of the typhoon. BFI is significantly large in the fourth quadrant of the typhoon, while waves are steep and have narrow frequencies and directional spectra. Freak waves resulting from nonlinear four-wave-wave interactions have a greater potential of occurring in the fourth quadrant of the typhoon than in the other quadrants. Furthermore, crossing sea states from two-wind-wave systems can be observed behind the eye of the typhoon. The crossing, two-wind systems are also dangerous sea states, although as observed, they are closer to linear wave conditions. Finally, the characteristics of possible freak wave conditions during typhoons are verified with field data.

  14. [Heat waves: health impacts].

    PubMed

    Marto, Natália

    2005-01-01

    During the summer of 2003, record high temperatures were reported across Europe, causing thousands of casualties. Heat waves are sporadic recurrent events, characterised by intense and prolonged heat, associated with excess mortality and morbidity. The most frequent cause of death directly attributable to heat is heat stroke but heat waves are known to cause increases in all-cause mortality, specially circulatory and respiratory mortality. Epidemiological studies demonstrate excess casualties cluster in specific risk groups. The elderly, those with chronic medical conditions and the socially isolated are particularly vulnerable. Air conditioning is the strongest protective factor against heat-related disorders. Heat waves cause disease indirectly, by aggravating chronic disorders, and directly, by causing heat-related illnesses (HRI). Classic HRI include skin eruptions, heat cramps, heat syncope, heat exhaustion and heat stroke. Heat stroke is a medical emergency characterised by hyperthermia and central nervous system dysfunction. Treatment includes immediate cooling and support of organ-system function. Despite aggressive treatment, heat stroke is often fatal and permanent neurological damage is frequent in those who survive. Heat related illness and death are preventable through behavioural adaptations, such as use of air conditioning and increased fluid intake. Other adaptation measures include heat emergency warning systems and intervention plans and environmental heat stress reduction. Heat related mortality is expected to rise as a consequence of the increasing proportion of elderly persons, the growing urban population, and the anticipated increase in number and intensity of heat waves associated with global warming. Improvements in surveillance and response capability may limit the adverse health conditions of future heat waves. It is crucial that health professionals are prepared to recognise, prevent and treat HRI and learn to cooperate with local health agencies. PMID:16684487

  15. Gravitational-Wave Detection (ii). Current Gravitational Wave Detector Results

    NASA Astrophysics Data System (ADS)

    Kanda, Nobuyuki

    2005-11-01

    The workshop session C1ii was focused on the results of recent operating detectors. 10 speakers presented the latest results of each experiments: ALLEGRO, GEO, LIGO, TAMA and VIRGO experiments. There were reports about searches for gravitational waves in analysis of observation data. The results are of no detection of gravitational waves, but observational upper-limits of gravitational waves are improved.

  16. Gravity waves in a realistic atmosphere.

    NASA Technical Reports Server (NTRS)

    Liemohn, H. B.; Midgley, J. E.

    1966-01-01

    Internal atmospheric gravity waves in isothermal medium, solving hydrodynamic equations, determining wave propagation in realistic atmosphere for range of wave parameters, wind amplitude, reflected energy, etc

  17. Protective effect of verapamil on renal tissue during shockwave application in rabbit model.

    PubMed

    Yaman, O; Sarica, K; Ozer, G; Soygür, T; Kutsal, O; Yaman, L S; Göŭş, O

    1996-08-01

    Although extracorporeal shockwave lithotripsy (SWL) is the treatment of choice for symptomatic urinary calculi, it has been shown in number of studies that adverse effects of high-energy shockwaves may be encountered in short- and long-term follow-up. To evaluate the possible protective effect of verapamil administration on renal tissue, both magnetic resonance imaging (MRI) and histopathologic examination were performed after SWL in rabbits. Thirty-five animals were divided into three groups. The 15 animals in the first group were fed verapamil (0.1 mg/kg) for 3 days. Another 15 animals received no medication but underwent SWL, and the remaining 5 animals received anesthesia alone (sham group). The animals were then subdivided into three groups according to the shockwave number applied (1000, 15,000, or 2000) and the aforementioned evaluations were performed 24 hours and 3 months after the procedure. We found prominent histopathologic alterations in animals not receiving any medication before SWL. Persistence of these pathologic alterations during 3 months of follow-up indicated the importance of preservation of renal architecture during high-energy shockwave application. On the other hand, animals under verapamil medication prior to SWL demonstrated only a limited degree of histopathologic alteration. Demonstration of a normal histologic pattern after 3 months supported the preservation of tissue structure by such medication. No significant histopathologic alteration could be observed in the sham-group animals, as expected. Our study demonstrates that verapamil is protective against shockwave-induced renal tubular damage. Such medications may be useful to avoid the proven histopathologic and functional side effects of high-energy shockwaves. PMID:8872729

  18. MHD Waves in Coronal Holes

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Krishna Prasad, S.

    2016-02-01

    This chapter reviews the observations of magnetohydrodynamic (MHD) waves in coronal holes focusing primarily on progress made in the past few years. It also discusses on the new evidences of wave damping and highlights how such observations can be used to probe coronal conditions through seismology. Numerous observations, using imaging and spectroscopic techniques, have revealed the presence of different MHD waves in these structures that can be categorized into compressive and incompressive waves. One of the most desirable characteristics of MHD wave observations in the solar atmosphere, is their dissipation. The energy carried by these waves has to be deposited at appropriate heights to facilitate coronal heating and solar wind acceleration. It turned out that the compressive waves are easy to dissipate with the conventional physical mechanisms whereas the incompressive waves require some special conditions.

  19. Transformation method and wave control

    NASA Astrophysics Data System (ADS)

    Chang, Zheng; Hu, Jin; Hu, Geng-Kai

    2010-12-01

    Transformation method provides an efficient way to control wave propagation by materials. The transformed relations for field and material during a transformation are essential to fulfill this method. We propose a systematic method to derive the transformed relations for a general physic process, the constraint conditions are obtained by considering geometrical and physical constraint during a mapping. The proposed method is applied to Navier's equation for elastodynamics, Helmholtz's equation for acoustic wave and Maxwell's equation for electromagnetic wave, the corresponding transformed relations are derived, which can be used in the framework of transformation method for wave control. We show that contrary to electromagnetic wave, the transformed relations are not uniquely determined for elastic wave and acoustic wave, so we have a freedom to choose them differently. Using the obtained transformed relations, we also provide some examples for device design, a concentrator for elastic wave, devices for illusion acoustic and illusion optics are conceived and validated by numerical simulations.

  20. Gravitational Waves: The Evidence Mounts

    ERIC Educational Resources Information Center

    Wick, Gerald L.

    1970-01-01

    Reviews the work of Weber and his colleagues in their attempts at detecting extraterrestial gravitational waves. Coincidence events recorded by special detectors provide the evidence for the existence of gravitational waves. Bibliography. (LC)

  1. Observations of running penumbral waves.

    NASA Technical Reports Server (NTRS)

    Zirin, H.; Stein, A.

    1972-01-01

    Quiet sunspots with well-developed penumbrae show running intensity waves with period running around 300 sec. The waves appear connected with umbral flashes of exactly half the period. Waves are concentric, regular, with velocity constant around 10 km/sec. They are probably sound waves and show intensity fluctuation in H alpha centerline or wing of 10 to 20%. The energy is tiny compared to the heat deficit of the umbra.

  2. Modeling Seismic Noise Body Waves

    NASA Astrophysics Data System (ADS)

    Stutzmann, E.; Farra, V.; Gualtieri, L.; Schimmel, M.; Ardhuin, F.

    2014-12-01

    Secondary microseismic noise is generated by non-linear interactions between ocean waves at the ocean surface. The sources correspond to pressure fluctuations close to the ocean surface. They generate acoustic waves in the ocean, which are then converted into P, SV, and Rayleigh waves in the deeper Earth layers. Rayleigh waves are the most energetic noise signal but body wave amplitude can be extracted using beamforming analysis. We analyze several typhoons recorded by the Southern California Seismic Network and we show that the detected P-wave amplitudes are frequency dependent. In order to understand the body wave generation mechanism, we model the P-wave amplitude. The sources are the power spectral density of the pressure derived from the ocean wave interaction model. They are distributed along the ocean surface and they are frequency dependent. We then compute the site effect of the ocean layer upon body waves generated by the noise sources. The site effect can be described as the constructive interference of multiply reflected P waves in the ocean that are then converted to P waves at the ocean-crust interface. It varies with frequency and ocean depth. Finally we compute the propagation from the source area to the network by taking into account seismic attenuation and geometrical spreading. We show that the modeled P-wave amplitude reproduce well the frequency dependent variations of the measured P-wave. This frequency dependent effect is due to both the source and site effect. We define the effective source as the product of the power spectral density of the pressure close to the surface and the site effect. We show that its maximum is consistent with the source location obtained by back projecting the slowness derived from the beamforming analysis. Finally, we show that body wave analysis enable to efficiently constrain the amount of sources generated by ocean wave reflected at the coast.

  3. ULF waves in the magnetosphere

    SciTech Connect

    Takahashi, Kazue )

    1991-01-01

    Research efforts in the area of magnetospheric ULF waves in the 1987-1990 period are reviewed. Attention is given to externally excited hydromagnetic waves including field line resonance, the global cavity mode, bow-shock-associated upstream waves, and Kelvin-Helmholtz waves. Consideration is given to internally excited Pc 4-5 pulsations and the role of these pulsations in the diffusion of ring-current ions based on the observed properties of the pulsations. 154 refs.

  4. Spiral Waves in Accretion Disks

    NASA Astrophysics Data System (ADS)

    Harlaftis, Emilios

    A review with the most characteristic spiral waves in accretion disks of cataclysmic variables will be presented. Recent work on experiments targeting the detection of spiral waves from time lapse movies of real disks and the study of permanent spiral waves will be discussed. The relevance of spiral waves with other systems such as star-planet X-ray binaries and Algols will be reviewed.

  5. Stationary waves in the wintertime mesosphere: Evidence for gravity wave filtering by stratospheric planetary waves

    NASA Astrophysics Data System (ADS)

    Lieberman, R. S.; Riggin, D. M.; Siskind, D. E.

    2013-04-01

    Quasi-stationary planetary-scale waves in the wintertime mesosphere and lower thermosphere (MLT) are thought to be forced in part by drag imparted by gravity waves that have been modulated by underlying stratospheric waves. Although this mechanism has been demonstrated numerically, there have been very few observational studies that examine wave driving as a source of planetary waves in the MLT. This study uses data from EOS Aura and TIMED between 2005 and 2011 to examine the momentum budget of MLT wintertime planetary waves. Monthly averages for January indicate that the dynamics of zonal wave number 1 are determined from a three-way balance among the Coriolis acceleration, the pressure gradient force, and a momentum residual term that reflects wave drag. The MLT circulations in January 2005, 2006, 2009, and 2011 are qualitatively consistent with a simple model of wave forcing by drag from gravity waves that have been modulated by stratospheric planetary waves. MLT winds during these years are also consistent with analyses from a high-altitude operational prediction model that includes parameterized nonorographic gravity wave drag. The importance of wave drag for the MLT momentum budget suggests that the gradient wind approximation is inadequate for deriving planetary-scale winds from global temperature measurements. Our results underscore the need for direct global wind measurements in the MLT.

  6. Nonlinear Waves on Stochastic Support: Calcium Waves in Astrocyte Syncytia

    NASA Astrophysics Data System (ADS)

    Jung, P.; Cornell-Bell, A. H.

    Astrocyte-signaling has been observed in cell cultures and brain slices in the form of Calcium waves. Their functional relevance for neuronal communication, brain functions and diseases is, however, not understood. In this paper, the propagation of intercellular calcium waves is modeled in terms of waves in excitable media on a stochastic support. We utilize a novel method to decompose the spatiotemporal patterns into space-time clusters (wave fragments). Based on this cluster decomposition, a statistical description of wave patterns is developed.

  7. ULTRASONIC MEASUREMENT MODELS FOR SURFACE WAVE AND PLATE WAVE INSPECTIONS

    SciTech Connect

    Schmerr, Lester W. Jr.; Sedov, Alexander

    2010-02-22

    A complete ultrasonic measurement model for surface and plate wave inspections is obtained, where all the electrical, electromechanical, and acoustic/elastic elements are explicitly described. Reciprocity principles are used to describe the acoustic/elastic elements specifically in terms of an integral of the incident and scattered wave fields over the surface of the flaw. As with the case of bulk waves, if one assumes the incident surface waves or plate waves are locally planar at the flaw surface, the overall measurement model reduces to a very modular form where the far-field scattering amplitude of the flaw appears explicitly.

  8. Energy in a String Wave

    ERIC Educational Resources Information Center

    Ng, Chiu-king

    2010-01-01

    When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed

  9. ECG Diagnosis: Hyperacute T Waves.

    PubMed

    Levis, Joel T

    2015-01-01

    After QT prolongation, hyperacute T waves are the earliest-described electrocardiographic sign of acute ischemia, preceding ST-segment elevation. The principle entity to exclude is hyperkalemia-this T-wave morphology may be confused with the hyperacute T wave of early transmural myocardial infarction. PMID:26176573

  10. Solitary waves and Bohmian mechanics

    PubMed Central

    Abbondandolo, Alberto; Benci, Vieri

    2002-01-01

    We study a Schrödinger-like equation with a nonlinear term. This nonlinearity has the effect of allowing the existence of highly concentrated stable solitary waves of a topological nature. Such solitary waves tend to move according to Bohmian mechanics. Therefore our model can be considered a nonsingular realization of de Broglie pilot wave theory. PMID:12397178

  11. Energy in a String Wave

    ERIC Educational Resources Information Center

    Ng, Chiu-king

    2010-01-01

    When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed…

  12. Cardiac R-wave detector

    NASA Technical Reports Server (NTRS)

    Gebben, V. D.

    1968-01-01

    Cardiac R wave detector obtains the systolic contraction signal of the human heart and uses it as a reference signal for the heart-assist pump cycle. It processes the electrocardiac signal /QRS wave complex/ of the natural heart in a sequence of operations which essentially elimates all components from the input signal except the R wave.

  13. The Wave Carpet: An Omnidirectional and Broadband Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Alam, M.-Reza

    2015-11-01

    Inspired by the strong attenuation of ocean surface waves by muddy seafloors, we have designed, theoretically investigated the performance, and experimentally tested the ``Wave Carpet:'' a mud-resembling synthetic seabed-mounted mat composed of vertically-acting linear springs and generators that can be used as an efficient wave energy absorption device. The Wave Carpet is completely under the water surface hence imposes minimal danger to boats and the sea life (i.e. no mammal entanglement). It is survivable against the high momentum of storm surges and in fact can perform even better under very energetic (e.g. stormy) sea conditions when most existing wave energy devices are needed to shelter themselves by going into an idle mode. In this talk I will present an overview of analytical results for the linear problem, direct simulation of highly nonlinear wave fields, and results of the experimental wave tank investigation.

  14. The wave and wave forecasting in the China Seas

    SciTech Connect

    Xu Fuxiang

    1993-12-31

    The China Seas located at the Southeastern part of the large Eurasia continent, and beside the largest ocean, the Pacific. They are greatly influenced by continent and the ocean. Due to it across the tropical zone, the subtropical zone and the extropical zone, the cold and warm air circulation in Northsouth is a very active exchange. In the summer, the South China Sea and the East China Sea are frequently hit by typhoon waves. In spring and autumn, the bohai sea, the Yellow sea and the East China Seas had series disasters caused by the extropical cyclone wave and the cold air wave. In this paper the time-space distribution and formative cases of wave disaster in the China Seas, and the wave monitoring and prediction system, the wave prediction method, and two automatic systems of numerical wave forecasting are briefly introduced.

  15. Wave-Particle Dynamics of Wave Breaking in the Self-Excited Dust Acoustic Wave

    NASA Astrophysics Data System (ADS)

    Teng, Lee-Wen; Chang, Mei-Chu; Tseng, Yu-Ping; I, Lin

    2009-12-01

    The wave-particle microdynamics in the breaking of the self-excited dust acoustic wave growing in a dusty plasma liquid is investigated through directly tracking dust micromotion. It is found that the nonlinear wave growth and steepening stop as the mean oscillating amplitude of dust displacement reaches about 1/k (k is the wave number), where the vertical neighboring dust trajectories start to crossover and the resonant wave heating with uncertain crest trapping onsets. The dephased dust oscillations cause the abrupt dropping and broadening of the wave crest after breaking, accompanied by the transition from the liquid phase with coherent dust oscillation to the gas phase with chaotic dust oscillation. Corkscrew-shaped phase-space distributions measured at the fixed phases of the wave oscillation cycle clearly indicate how dusts move in and constitute the evolving waveform through dust-wave interaction.

  16. Gravity wave initiated convection

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1990-01-01

    The vertical velocity of convection initiated by gravity waves was investigated. In one particular case, the convective motion-initiated and supported by the gravity wave-induced activity (excluding contributions made by other mechanisms) reached its maximum value about one hour before the production of the funnel clouds. In another case, both rawinsonde and geosynchronous satellite imagery were used to study the life cycles of severe convective storms. Cloud modelling with input sounding data and rapid-scan imagery from GOES were used to investigate storm cloud formation, development and dissipation in terms of growth and collapse of cloud tops, as well as, the life cycles of the penetration of overshooting turrets above the tropopause. The results based on these two approaches are presented and discussed.

  17. Plasma wave accelerator. II

    SciTech Connect

    Mori, W.; Joshi, C.; Dawson, J.M.

    1982-01-01

    It was shown that the insertion of a cross magnetic field prevents the particles from getting out of phase with the electric field of the plasma wave in the beat wave accelerator scheme. Thus, using a CO/sub 2/ laser, n/sub c//n/sub e/ = (..omega../sub 0//..omega../sub p/)/sup 2/ approx. 35, and a 300 kG magnetic field, electrons can be (in principle) accelerated to 100 GeV in 2 meters. For comparison without the magnetic field, the same energies may be obtained in a n/sub c//n/sub e/ approx. 10/sup 5/ plasma over a distance of 100 meters.

  18. Sources of gravitational waves

    NASA Technical Reports Server (NTRS)

    Schutz, Bernard F.

    1989-01-01

    Sources of low frequency gravitational radiation are reviewed from an astrophysical point of view. Cosmological sources include the formation of massive black holes in galactic nuclei, the capture by such holes of neutron stars, the coalescence of orbiting pairs of giant black holes, and various means of producing a stochastic background of gravitational waves in the early universe. Sources local to our Galaxy include various kinds of close binaries and coalescing binaries. Gravitational wave astronomy can provide information that no other form of observing can supply; in particular, the positive identification of a cosmological background originating in the early universe would be an event as significant as was the detection of the cosmic microwave background.

  19. Waving potential in graphene

    NASA Astrophysics Data System (ADS)

    Yin, Jun; Zhang, Zhuhua; Li, Xuemei; Yu, Jin; Zhou, Jianxin; Chen, Yaqing; Guo, Wanlin

    2014-05-01

    Nanoscale materials offer much promise in the pursuit of high-efficient energy conversion technology owing to their exceptional sensitivity to external stimulus. In particular, experiments have demonstrated that flowing water over carbon nanotubes can generate electric voltages. However, the reported flow-induced voltages are in wide discrepancy and the proposed mechanisms remain conflictive. Here we find that moving a liquid-gas boundary along a piece of graphene can induce a waving potential of up to 0.1 V. The potential is proportional to the moving velocity and the graphene length inserted into ionic solutions, but sharply decreases with increasing graphene layers and vanishes in other materials. This waving potential arises from charge transfer in graphene driven by a moving boundary of an electric double layer between graphene and ionic solutions. The results reveal a unique electrokinetic phenomenon and open prospects for functional sensors, such as tsunami monitors.

  20. Waving potential in graphene.

    PubMed

    Yin, Jun; Zhang, Zhuhua; Li, Xuemei; Yu, Jin; Zhou, Jianxin; Chen, Yaqing; Guo, Wanlin

    2014-01-01

    Nanoscale materials offer much promise in the pursuit of high-efficient energy conversion technology owing to their exceptional sensitivity to external stimulus. In particular, experiments have demonstrated that flowing water over carbon nanotubes can generate electric voltages. However, the reported flow-induced voltages are in wide discrepancy and the proposed mechanisms remain conflictive. Here we find that moving a liquid-gas boundary along a piece of graphene can induce a waving potential of up to 0.1 V. The potential is proportional to the moving velocity and the graphene length inserted into ionic solutions, but sharply decreases with increasing graphene layers and vanishes in other materials. This waving potential arises from charge transfer in graphene driven by a moving boundary of an electric double layer between graphene and ionic solutions. The results reveal a unique electrokinetic phenomenon and open prospects for functional sensors, such as tsunami monitors. PMID:24800734