Numerical simulation on an improved electro-hydraulic extracorporeal shock wave lithotripsy / 医用生物力学

Objective To simulate the pressure field for extracorporeal shock wave lithotripsy (ESWL) by attaching additional reflector with different angles at the side of the ellipsoidal reflector edge in the Dornier HM3 lithotripter. Methods Based on axisymmetric Euler equations and hybrid grid improved CE/SE numerical scheme, the pressure field of shock wave changed by the additional reflector in ESWL was simulated. Results Pressures of the additional reflector with different angles near the focus were compared. There were significant 50% increases of both the positive and negative pressure peaks in the pressure field as compared to ESWL without additional reflector. The peak pressures were gradually decreased with the reflector angle increasing. The peak pressure of 45° reflector angle was about 25% less than that 0° reflector angle. Conclusions At the initial stage of stone comminution, stones were broken into smaller pieces due to the more concentrated energy produced by the additional reflector, which could reduce the firing frequency to achieve the same or higher stone comminution efficiency. The numerical simulation results provide a reliable numerical calculation result and useful reference for the improvement and clinical application of ESWL lithotripter.

Removal of Kidney Stones by Extracorporeal Shock Wave Lithotripsy Is Associated with Delayed Progression of Chronic Kidney Disease

PURPOSE: This study aimed to elucidate whether stone removal by extracorporeal shock wave lithotripsy (ESWL) is associated with delayed chronic kidney disease (CKD) progression. MATERIALS AND METHODS: We conducted a retrospective analysis of 131 nephrolithiasis patients with stage 3 and 4 CKD. We collected baseline clinical and laboratory data, kidney stone characteristics, and history of receiving ESWL. We classified study patients into two groups according to whether they underwent ESWL or not (Non-ESWL group vs. ESWL group). We initially compared annual estimated glomerular filtration rate (eGFR) changes of Non-ESWL group with those of ESWL group before undergoing ESWL. In the next step, we sought to compare annual eGFR changes in the same patients before and after ESWL. Finally, we compared annual eGFR changes between success and failure groups among patients undergoing ESWL. RESULTS: The mean age of the patients was 62 years and 72.5% were male. The mean observation period was 3.2 years. Non-ESWL group and ESWL group before undergoing ESWL showed similar annual eGFR changes (-1.75+/-6.5 vs. -1.63+/-7.2 mL/min/1.73 m2/year, p=0.425). However, eGFR declined slower after undergoing ESWL than before ESWL (annual eGFR changes, -0.29+/-6.1 vs. -1.63+/-7.2 mL/min/1.73 m2/year, p<0.05). In addition, among patients in ESWL group, eGFR declined faster in the failure group than in the success group (annual eGFR change, -1.01+/-4.7 vs. -0.05+/-5.2 mL/min/1.73 m2/year, p<0.05). CONCLUSION: Our results suggest that stone removal by ESWL is associated with delayed deterioration of renal function in CKD patients with nephrolithiasis.

Numerical simulation of electro-hydraulic extracorporeal shock wave lithotripsy with single-pulse or dual-pulse / 医用生物力学

Objective To study the pressure field with the single-pulse and the dual-pulse for extracorporeal shock wave lithotripsy (ESWL) by numerical simulation, and to compare and analyze the results. Methods2D axisymmetric Euler equations and hybrid grids improved CE/SE numerical scheme were employed to simulate the pressure field of underwater shock wave in ESWL. Results The CE/SE shock wave dynamics method could successfully track the transmission of shock wave front, and the simulation solution could preferably reveal the focusing properties near the focus of ESWL: the pressure of dual-pulse was about the twice that of the single-pulse near the focus, and the higher lithotriptic efficiency could be achieved when the dual-pulse was much closer to the focus than the single pulse. A negative pressure with high absolute value was observed after the positive pressure occurred near the focus. ConclusionsThe adoption of electro hydraulic lithotripter could effectively improve the efficiency of stone comminution and the cavitation of shock wave focus was unavoidable, which provided a reliable numerical simulation result for the design and application of ESWL lithotripter in clinic.

Delayed Splenic Rupture and Pancreatic Pseudocyst Following Extracorporeal Shock Wave Lithotripsy for a Urolithiasis

Extracorporeal shock wave lithotripsy (ESWL) has revolutionized the management of urolithiasis since 1980. Although it has proved to be a safe, effective treatment modality, it is not free of complications. As this procedure has become more widely available, complications as a result of injury to the kidney and the surrounding organs are being increasingly recognized. Those reported complications include hepatic hematoma, biliary obstruction, pancreatitis, colonic and splenic injury, bowel perforation, psoas abscess, aortic aneurysm rupture, portal and iliac vein thrombosis, retroperitoneal and brain hemorrhage, gastric erosions, pulmonary contusions and cardiac arrhythmias. Physicians caring for these patients should be mindful of these complications and keep an eye open to spot them. We report here on a case of a young male patient who developed splenic rupture and a pancreatic pseudocyst after undergoing extracorporeal shock wave lithotripsy (ESWL) for treating a left upper ureter stone.

Sedative - Analgesic Effect with Diazepam - Fentanyl for Extracorporeal Shock Wave Lithotripsy / 대한마취과학회지

Extracorporeal shock wave lithotripsy(ESWL) for urinary calculi is usually performed under general anesthesia, regional anesthesia or intravenous anesthesia. We evaluated the sedativeanalgesic effeet and untoward effects of diazepam-fentanyl for ESWL. 60 patients were belonged to physical status 1 or 11 of ASA classification who injected diazepam(5~10 mg) and fentanyl(1.5 ug/kg) at 2 minutes were as follows The results were as follows; 1) Mean arterial pressure(MAP) was significantly decreased in 3-10 minutes after injection compared to baseline value. 2) Heart rate(HR) was statistically nonsignificant but slightly decreased from 2 minutes after injection. 3) Respiratory rate(RR) and arterial oxygen saturation(SaO2) were significantly decreased until 15 miuntes after injection but SaO was not decreased below 92.7% and RR was not decreased below 13 rates/minute. 4) Pain and movement during ESWL developed in 18 cases but repositioning and discon- tinuation of EWSL were not necessary. Episodes of desaturation(SaO2<90%) developed in 2 cases. 5) Postoperative dizziness developed in 24 cases. nausea and vomiting developed in a few cases. We concluded that intravenous administration of diazepam-fentanyl is more convenient and simpler than other anesthetic technique for ESWL.

Extracorporeal Shock Wave Lithotripsy with Northgate SD-3 in 202 Patients with 259 Urinary Calculi / 대한비뇨기과학회지

During the last 16 months period between October 1988 and December 1989, 202 patients, 259 urinary calculi, have been treated with Northgate SD-3 lithotripter. The calculi were localized with ultrasound, and only sedation with diazepam and meperidine was used intravenously in all patients. The following results were obtained ; 1. 315 sessions had been in 202 patients, average timement was treatment was 67 minutes, and mean number of impulse was 2,251. 2. The location of stone was 42.2% caliceal, 13.1 % pelvic, 37.5 % ureteral and 6.9% branched renal calculi, measuring 5mm to 38mm. 3. The preoperative concomitant procedures were push-back of ureteral stone in 7 cases, ureteral catheter bypass in 5 cases, double-pigtail stent indwelling in 30 cases and percutaneous nephrolithotripsy in 4 cases. 4. The overall success rate (X-ray negative or fragments less than 3mm) at postoperative 2 months, was 82.6 %. 5. Complication occurred in 9.8% of all treatments. Therefore Northgate SD-3 lithotripter is safe and efficient for the treatment of the urinary calculi.