Physiologic and Extracorporeal Shock Wave Lithotripsy (ESWL) data were collected before, during and after ESWL from four patient groups employing different anesthetic techniques (epidural anesthesia, general anesthesia with low-volume conventional mechanical ventilation or with unsynchronized high frequency jet ventilation (HFJV) or with HFJV synchronized to the heart rate). The primary goal was to determine if synchronized HFJV had any beneficial effects. A synchronization unit was fabricated that triggered one HFJV breath, per heart beat, delivered 30 milliseconds after the shock wave. This allowed only expiratory motion during shock wave administration. Results were analyzed using one-way analysis of variance, Students t-tests and chi-square tests with significance at p 0.05. Results showed that renal stone excursion was significantly less in HFJV groups and that significantly more patients required re-treatment in non-HFJV groups. No results indicated that synchronizing HFJV had any further benefits than unsynchronized HFJV.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (p. 133-146).

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 73-87).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Shock wave lithotripsy is the preferred treatment modality for kidney stones in the United States. Despite clinical use for over twenty-five years, the mechanisms of stone fragmentation are still under debate. A piezoelectric array was employed to examine the effect of waveform shape and pressure distribution on stone fragmentation in lithotripsy. The array consisted of 170 elements placed on the inner surface of a 15 cm-radius spherical cap. Each element was driven independently using a 170 individual pulsers, each capable of generating 1.2 kV. The acoustic field was characterized using a fiber optic probe hydrophone with a bandwidth of 30 MHz and a spatial resolution of 100 μm. When all elements were driven simultaneously, the focal waveform was a shock wave with peak pressures p+ =65±3MPa and p−=−16±2MPa and the −6 dB focal region was 13 mm long and 2 mm wide. The delay for each element was the only control parameter for customizing the acoustic field and waveform shape, which was done with the aim of investigating the hypothesized mechanisms of stone fragmentation such as spallation, shear, squeezing, and cavitation. The acoustic field customization was achieved by employing the angular spectrum approach for modeling the forward wave propagation and regression of least square errors to determine the optimal set of delays. Results from the acoustic field customization routine and its implications on stone fragmentation will be discussed. / National Institutes of Health DK043881

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Objective: Pancreatic stones result from chronic pancreatitis and can occur in the main pancreatic duct, pancreatic branches or parenchyma. Although extracorporeal shock wave lithotripsy (ESWL) is considered the first-line treatment, per-oral pancreatoscopy (POP) has emerged as a useful method for treating pancreatic stones. The aim of this systematic review and meta-analysis was to determine the efficacy and safety of POP-guided lithotripsy, electrohydraulic lithotripsy (EHL) and laser lithotripsy (LL), in patients with pancreatolithiasis. Methods: Literature review was conducted in PubMed, OVID, MEDLINE and Cochrane Library databases for studies published up to August 2020. Results: Altogether 15 studies were analyzed, of which 11 were retrospective and four were prospective. The studies comprised 370 patients, of whom 66.4% were male. The patients underwent 218 EHL and 155 LL. The pooled technical and clinical success rate of the overall POP was 88.1% and 87.1%. For EHL-POP, the pooled technical success rate was 90.9% (95% CI 87.2%-95.2%) and the pooled clinical success rate was 89.8% (95% CI 87.2%-95.2%). While for LL-POP, the pooled technical and clinical success rate was 88.4% (95% CI 85.9%-95.1%) and 85.8% (95% CI 80.6%-91.6%). In total 43 adverse events occurred (12.1%; 95% CI 8.7%-15.5%). Conclusion: POP-guided lithotripsy has a high rate of technical and clinical success for managing pancreatolithiasis with a low complication rate. Both EHL-POP and LL-POP achieve similar efficacy in the endoscopic therapy of pancreatolithiasis. Further large randomized controlled trials are needed to compare EHL-POP and LL-POP with ESWL and evaluate whether POP may replace ESWL as the first-line management of pancreatolithiasis. / Revisión por pares

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 91-100).

Not available / text

This thesis is concerned with the design and construction of an electromagnetic acoustic transducer (EMAT) and the characterisation of its acoustic field both conventionally, using a hydrophone and with high resolution laser illuminated schlieren techniques. During the early 80s the introduction of the EMA T along with the other types of shock wave source used for lithotripsy, revolutionised the treatment of stone disease. The process of shock wave induced destruction of calculi and the use of shock waves in other areas of medicine will be discussed, along with the causes and effects of stone disease in man. For the first time high temporal and spatial resolution schlierenimages of the shock waves and there interaction with simulation kidney stones have been recorded. The technique provides a clearer picture of the fragmentation process and may assist research into the suitability of shock wave treatment in other areas of medicine currently under investigation. Schlieren studies of the acoustic field have shown the complex structure of not only the EMA T shock wave, but also that associated with cavitation in the field. The primary source of cavitation is due to the rupture and subsequent collapse of bubbles generated in the water by the strong rarefaction phase of the shock wave. The images give evidence for the interaction of these 'primary' cavitation shocks with bubbles in the field, the collapse of some of these bubbles giving rise to additional or 'secondary' cavitation shocks. An optical lensing effect introduced by the shock has also been investigated. Objects seen through or immersed in the field of an EMAT shock wave such as cavitation, appear highly distorted, due to the strong positive and negative lensing effects associated with the changing refractive index of the compression and rarefaction cycles of the shock wave.

Conclusion This series of investigations demonstrated how we can apply our knowledge to improve the treatment outcome of ESWL. Based on clinical information, such as age, suitable candidates for ESWL can be identified, and hence better application of ESWL can be achieved. With an understanding of the benefits and limitations of imaging (NCCT and intravenous urography), treatment success can be predicted, and better treatment plans for patients can be formulated. A policy of more liberal use of analgesia during ESWL can also help to improve the treatment outcomes of patients. Finally, with the use of different assessment methods, the true impact of various new technologies or treatment protocols can be assessed, and the results can lead to better understanding of ESWL and also improvement in the treatment outcomes. / Materials and Methods In a retrospective review of treatment information of 2192 patients, the effect of age on stone-free rates after ESWL was assessed. Next, in a prospective study, the role of stone parameter, measured using non-contrast computerized tomography (NCCT), in predicting the treatment outcomes of upper ureteric stones was examined. The general applicability of caliceal pelvic height (CPH) in determining the treatment outcomes for lower caliceal stones for three different lithotriptors was assessed in the third study. In another retrospective comparative study, the effect on treatment outcomes of additional usage of intravenous analgesic during ESWL, as compared to oral analgesic premedication alone, was analyzed. Finally, the feasibility of the use of two statistical methods, logistic regression and matched-pair analysis, in comparing the treatment results of different lithotriptors was investigated. / Objectives Despite the initial success of extracorporeal shock wave lithotripsy (ESWL), the performance of the contemporary machines has never been as good as that of the first-generation machine. Therefore, a series of studies was conducted to advance the current knowledge of ESWL and investigate possible ways to further optimize the treatment outcomes. / Results We found that the stone-free rate after ESWL for older patients with renal stones, but not for those with ureteric stones, was significantly lower than that of younger patients. Stone parameters measured using NCCT, namely, mean stone density, stone volume, and skin-to-stone distance, were significant predictive factors for successful ESWL for upper ureteric stones. However, caliceal pelvic height, measured by intravenous urography, was a significant predictor of treatment outcomes of lower caliceal stones for only the Piezolith 2300 lithotriptor, and not the other two types of lithotriptors. The additional usage of intravenous analgesic improved the effectiveness quotient and hence treatment outcomes of ESWL. Finally, both logistic regression and matched-pair analysis were found to be feasible approaches for the comparison of the performance of different lithotriptors. / Chi-Fai Ng. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 224-243). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.