Use of local anesthesia for extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy is being performed at many centers with the use of either general or epidural anesthesia. We report our experience with 39 patients treated by extracorporeal shock wave lithotripsy under local anesthesia. These patients tolerated the procedure well and had good fragmentation of the stones. Of the patients 18 were treated on an outpatient basis. In selected patients local anesthesia offers an alternative that can decrease the risk of anesthesia, and reduce the cost and hospital stay associated with extracorporeal shock wave lithotripsy.     

Initial experience with local anesthesia in extracorporeal shock wave lithotripsy

The report concerns initial experience with local anesthesia in the treatment of urolithiasis by extracorporeal shock wave lithotripsy. This form of anesthesia is well tolerated for stones of limited size and hardness, though the patients must be carefully selected.     

Treatment of ureteral calculi by extracorporeal shock wave lithotripsy at a multi-use center

We reviewed our experience with extracorporeal shock wave lithotripsy therapy in 138 patients who presented with mid and upper ureteral calculi. In the patients who had successful stone manipulation back into the renal collecting system the success rate was significantly higher compared to that for stones treated primarily within the ureter (92.8 versus 80.8 per cent, p less than 0.05). Among the stones treated within the ureter the success rates appeared to be similar for stones treated in situ (83.3 per cent) compared to those treated when a catheter could be placed alongside the calculus (79.3 per cent). Higher voltage and more shock waves were administered to stones treated within the ureter compared to stones that were manipulated back into the kidney. However, this increase power did not enhance the success rate. In addition, it appears that a plain film of the abdomen obtained within 24 hours of lithotripsy treatment is a good predictor of success as defined by the rate free of stones at 6 weeks of followup. Our results from a community-based multi-use lithotripsy center suggest that ureteral stone manipulation should be attempted before extracorporeal shock wave lithotripsy for mid and upper ureteral calculi.     

QRS-activated ventilation during general anesthesia for extracorporeal shock wave lithotripsy

High frequency ventilation has been claimed to improve the efficiency of extracorporeal shock wave lithotripsy (ESWL) by minimizing the movement of urinary stones during the procedure. A ventilatory mode, QRS-activated ventilation, was developed in which the stones remain motionless during the delivery of shock waves. As the shock wave is triggered to occur approximately 20 milliseconds after the R wave of the QRS complex, the mechanical breath was synchronized to occur approximately 150 ms later. QRS-activated ventilation is used in 16 patients undergoing ESWL under general anesthesia. Tidal volume was set at 3 ml/kg (234 +/- 36 ml; mean +/- SD) at a rate that equaled the heart rate (71 +/- 9 beats/min). The time between the R wave and the initiation of mechanical breath (T1) was 124 +/- 25 ms, time of mechanical breath itself (T2) was 431 +/- 67 ms, and time between end of T2 and next R wave (T3) was 264 +/- 84 ms. End-tidal CO2 measured by the large breath technique was 28.1 +/- 4.8 mmHg. During the clinical use of QRS-activated ventilation and during earlier studies using an EKG simulator and a test lung, the shock wave occurred invariably at end-expiration even at high heart rates.     

Retroperitoneal air, extracorporeal shock wave lithotripsy and epidural anesthesia

During a 13-month period, 1,344 patients underwent extracorporeal shock wave lithotripsy. Plain x-rays done routinely 24 hours after lithotripsy to assess stone fragmentation revealed evidence of retroperitoneal air in 6 patients. All 6 patients had epidural anesthesia induced by loss of resistance to air in a syringe to identify the epidural space. It was believed likely that this was the cause of the air and 2 types of distribution were identified: 1 showed tracking of air along spinal nerves and 1 along tissue planes. This hypothesis eventually was confirmed by 2 patients in whom the air was identified after epidural anesthesia but before extracorporeal shock wave lithotripsy. Retroperitoneal air is found in a small number of patients undergoing epidural anesthesia and extracorporeal shock wave lithotripsy, and physicians treating these patients in the early postoperative period should be aware of this possible radiological finding and appreciate its benign nature.     

Anaesthesia for extracorporeal shock wave lithotripsy

The anaesthetic considerations of patients presenting for extracorporeal shock wave lithotripsy are described. Regional anaesthesia with sedation may be preferable to general anaesthesia for patients undergoing this form of therapy. If regional anaesthesia is contra-indicated, general anaesthesia using controlled ventilation with muscle relaxation, supplemented with a narcotic and a low concentration of volatile anaesthetic has been found to be a suitable alternative. The additional epidural preparation time has to be balanced against the benefits of easier patient transfer, especially during multi-stage procedures, and better postoperative analgesia. The epidural catheter can be left in situ in patients who require multiple treatments or who may experience severe ureteric pain as the resulting 'sand mass' is passed. Epidural space localisation using a 'loss of resistance to saline' technique is recommended, in order to avoid the possible risk of damage to the spinal cord and emerging nerves (due to the presence of an air-water interface). Patients with cardiac insufficiency need special consideration, in view of the effects of immersion on right and left heart filling pressures.     

Effects and side effects of ureteral stenting during extracorporeal shock wave lithotripsy

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.     

The use of local anesthesia in second generation extracorporeal shock wave lithotripsy: eutectic mixture of local anesthetics

Extracorporeal shock wave lithotripsy (ESWL&) can be painful. Of our population of patients treated with a Siemens Lithostar device 51.4% needed intravenous analgesia. A eutectic mixture of local anesthetics, a hydrophylic cream containing 25 mg. lidocaine and 25 mg. prilocaine per gm., proved to be effective for local analgesia. Therefore, we investigated its effectiveness during ESWL. With randomized, double-blind application the eutectic mixture of local anesthetics and placebo were evaluated in 83 patients according to the percentage of patients who required intravenous analgesia during ESWL. Of 40 patients treated with the eutectic mixture of local anesthetics 12 (30%) needed supplementary fentanyl citrate, compared to 23 of 43 (53%) placebo treated patients. Although there is no statistical significance (p = 0.32), the eutectic mixture of local anesthetics does decrease pain during ESWL and it should be particularly useful for patients in whom intravenous analgesia is contraindicated.     

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

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.     

Limitations of extracorporeal shock wave lithotripsy

PURPOSE OF REVIEW: Extracorporeal shock wave lithotripsy (ESWL) is the preferred modality for the treatment of renal and upper ureteric calculi. The present review focuses on the limitations of ESWL, where recent developments have tried to identify patients who are unlikely to succeed with ESWL and where improvements in shock wave delivery may increase successful stone fragmentation. RECENT FINDINGS: Evaluation of patients prior to ESWL is especially important, and the use of imaging in the decision process, with the use of computed tomography attenuation values and skin-to-stone distance, can help improve our ability to identify suitable patients for shock wave treatment. Continued research into the methods of shock wave delivery techniques and lithotripter designs will help achieve better stone fragmentation rates with reduced side effects. SUMMARY: The importance of traditional factors in predicting ESWL success, such as stone size, location, composition and renal anatomy, are well known. More recently, authors have created nomograms to predict stone-free outcome after ESWL. Others have used the information obtained from computed tomography to predict stone comminution. In addition, modifications in shock wave delivery by altering shock rate and voltage have been researched in an effort to improve shock wave efficacy.     

冲击波碎石技术的发展动态

1980年2月,世界上第一台Dornier HM1（人体型机）冲击波碎石机在德国应用于临床。1984年,DomierHM3型冲击波碎石机通过了美国FDA认证,因其有效、安全,不久就成为治疗上尿路结石的首选方法。30年来冲击波碎石机经历了一、二、三代的发展。与第一代DomierHM3碎石机相比,第二、三代碎石机的可操作性和功能性有了明显进步,