Mobile extracorporeal shockwave lithotripsy

During the last 18 months, extracorporeal shockwave lithotripsy (ESWL) has been provided at Epsom District Hospital using a mobile unit containing a Dornier HM4 lithotriptor. Patients with upper ureteric and renal stones were selected for treatment, which was performed without anaesthesia or sedation as a day-case procedure; 83 patients were treated, 5 of them with bilateral stones. Seventy patients required 1 treatment session, 17 required 2 and 1 patient required 3. There were no serious complications but 3 patients needed ureteroscopy to remove obstructing stones. The overall success rate was 86%. The cost to treat each NHS patient was 253 pounds. Mobile lithotripsy as a day-case procedure is a safe and cost-effective means of treating urolithiasis and can be performed in a District General Hospital.     

Ambulatory extracorporeal shockwave lithotripsy

The Kidney Stone Center in Fort Lauderdale, Florida, is an ambulatory ESWL facility where 226 patients have been treated since July, 1985. A total of 258 kidneys were treated over a period of five months with a success rate of 99 per cent. The post-treatment admission rate, both immediate and delayed, was 14.2 per cent. Outpatient ESWL treatment of both renal and ureteral calculi is feasible, medically safe, and cost-effective.     

Lipids in the urine after extracorporeal shockwave lithotripsy

Lipid corpuscles have been found in the urine in about 40 per cent of women (4/10) after extracorporeal shock wave lithotripsy, however this lipuria is very rare in men (1 or 2 per cent of cases) and less pronounced. During three days after treatment, this post-therapeutic lipuria was found to be independent of the age of patients, of the site of the calculi, of their chemical composition or of the number of shock waves administered. This lipuria probably results from the liquefaction of peri-pelvic fat tissue by exothermic reaction. These lipid corpuscles consist mostly of triglycerides and to a lesser extent phospholipids with a very small proportion of cholesterol and fatty acids.     

Acupuncture for pain in extracorporeal shockwave lithotripsy

BACKGROUND AND PURPOSE: In most cases, analgesia is required for extracorporeal shockwave lithotripsy (SWL) treatment. Commonly, a combination of a sedative and a synthetic opioid is used, with a wide range of undesirable side effects. To provide an alternative analgesic especially for outpatients, we performed a prospective trial investigating the usefulness of acupuncture. PATIENTS AND METHODS: A series of 90 patients were included in the study, 49% of whom presented with renal calculi and 10% with proximal-, 10% with middle-, and 31% with distal-ureteral stones. Pain control was performed by acupuncture in the traditional Asian method. The intensity of pain and patient satisfaction were assessed a visual analog scale (VAS). Patients with previous SWL under conventional analgesia also were asked about differences in pain and satisfaction. RESULTS: No significant side effects occurred. The median pain score on the VAS was 2/10 (interquartile range 1). Six patients (6.6%) specified a pain intensity of >4, and in 4 patients (4.4%), a conventional analgesic had to be given to finish SWL. The median satisfaction level was 2/5 (interquartile range 1). Nearly all (93.4%) of the patients would opt again for acupuncture in case of repeated SWL. CONCLUSION: In many patients, acupuncture achieves satisfactory pain control for SWL. Further randomized multi-institutional studies are needed to confirm this conclusion.     

Impact of shockwave coupling on efficacy of extracorporeal shockwave lithotripsy

PURPOSE: To evaluate the impact of a slow gated treatment rate on the efficacy of extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: From August 1990 to July 2002, 40,462 SWL procedures were performed using the slow frequency electrocardiography (ECG)-gated lithotripter (82.5%) and fast frequency ECG-ungated (17.5%) modes for the Medstone STS lithotripter. Treatment characteristics, including the mode of SWL, location and size of the stone, re-treatment status, auxiliary procedures required, perioperative complications, and treatment outcomes, were recorded. The stone-free rate was reported by the treating physician on the basis of the finding of no residual stone fragments on a plain radiographic image. RESULTS: The treatment rate for the slow mode was a mean of 79.6 shocks/min, while the rate for the fast mode was 120/min. The total procedure time was 47.0 minutes for the slow mode and 40.6 minutes for the fast. The overall stone-free rate was higher for slow (66.9%) than fast (63.6%) procedures (P < 0.001). The stone-free rate for 1- to 10-mm stones was higher for the slow procedures (75.7%) than the fast procedures (70.7%; P < 0.001). Upper-ureteral stones responded better to slow treatment in terms of stone-free rate (79.5% v 72.6%; P < 0.001), re-treatment rate (6.5% v 8.0%, P = 0.05), auxiliary-procedure rate (6.1% v 8.9%; P = 0.01), and efficiency quotient (71 and 62). There was no significant difference in complication rates overall between slow and fast treatment. CONCLUSIONS: With a minimal increase in procedure time, greater efficacy can be obtained for the treatment of radiopaque stones with a slower shock-delivery rate. In particular, upper-ureteral calculi and calculi <10 mm benefit from a slower treatment rate.     

The history of extracorporeal shockwave lithotripsy in Spain

We give a historical outline of urinary lithiasis with emphasis in the alternative therapeutic options to surgery. We expose the previous steps that led to the birth of extracorporeal shockwave lithotripsy and its implementation in our country.     

Extracorporeal shockwave lithotripsy and litholytic therapy in cholelithiasis.

Extracorporeal shockwave lithotripsy (ESWL) and litholytic therapy were used in 100 patients over a period of 16 months. ESWL was carried out with a Lithostar Plus and chenodeoxycholic acid was used as the lytic agent, given until 3 months after complete disappearance of stones. Within a period of 8-12 months, stones disappeared completely in 82 per cent of the patients who had a single stone less than or equal to 20 mm in diameter and in 50 per cent of those with a single stone greater than 20 mm in size or with multiple stones. Complications requiring surgery developed in five patients: three had acute cholecystitis and two developed acute pancreatitis. Of the patients in whom complete stone clearance was achieved, two of 11 followed up developed recurrence of stones 4 months after cessation of lytic therapy.     

Effect of diuresis on extracorporeal shockwave lithotripsy treatment of ureteric calculi

OBJECTIVE: To evaluate the effect of diuresis during extracorporeal shockwave lithotripsy (ESWL) treatment of ureteric calculi. The purpose is to improve stone fragmentation and clearance rates. MATERIALS AND METHODS: One hundred and six consecutive patients with ureteric calculi at different levels were treated by ESWL using Siemens Lithostar 2 machine. Patients have been randomized into two treatment groups. The first group was treated by standard ESWL and included 54 patients. The second group was treated by ESWL with diuresis during the ESWL session. Shock waves were given at a rate of 90 shocks/minute with energy starting from 10 up to 18 KV. During the ESWL session the patient belonging to the second group received i.v. infusion of 500 ml normal saline containing 40 mg furosemide as a diuretic. The stone fragmentation and clearance rates were the two end points for evaluation. RESULTS: The average number of sessions per stone was 1.92 and 1.5 and the average number of shocks per stone was 6295 and 5300 for the first and second treatment groups respectively. Stone fragmentation rate was 47/54 (87%) and 50/52 (96.2%) and the stone clearance (success) rate was 47/54 (87%) and 48/52 (92.3%) for the first and the second groups respectively. Analysis of the results in relation to stone location showed that the two treatment groups were comparable for upper and middle ureteric calculi. However for distal ureteric stones, the addition of diuresis during ESWL was associated with a lower mean number of ESWL sessions and shocks per stone compared with standard ESWL: 1.38 and 4950 for ESWL with diuresis compared with 2.9 and 8544 for standard ESWL respectively. The stone fragmentation and 3-month clearance (success) rates were clearly higher: 93.8% and 87.5% respectively for ESWL with diuresis compared with 70.6% (for both fragmentation and clearance) with standard ESWL. CONCLUSIONS: Diuresis is a useful, inexpensive and safe adjunct to ESWL of ureteric stones. It markedly improves the results of ESWL treatment of distal ureteric stones compared with standard ESWL.     

Does extracorporeal shockwave lithotripsy cause hypertension?

Several series have suggested that the incidence of hypertension following extracorporeal shockwave lithotripsy (ESWL) may be as high as 8%. In this study, changes in blood pressure and the incidence of hypertension have been observed in 733 patients 12 to 44 months after renal ESWL on the Dornier HM3. The incidence of hypertension following ESWL was 8.1%. In patients with a pre-ESWL diastolic pressure less than 90 mmHg, the incidence of those with a diastolic greater than or equal to 100 mm Hg post-operatively was significantly greater than that predicted by historical data. There was no overall change in the mean blood pressure of the group. The hypertensive risk of ESWL remains unclear. However, blood pressure surveillance should be performed following ESWL and a prospective study is required.     

Is extracorporeal shockwave lithotripsy suitable treatment for lower ureteric stones?

Forty patients with lower ureteric calculi for which intervention was considered desirable have been treated by in situ extracorporeal shockwave lithotripsy (ESWL) on the Dornier HM3 Lithotripter using a modified technique. Stone localisation was satisfactory in all patients. Adequate disintegration was achieved in 90% of patients following one treatment; 34 patients have been followed up for at least 3 months and 27 of these are stone-free (79%). Treatment failed in 4 patients and 2 of these had dense lower ureteric stone streets as a result of previous ESWL. The retreatment rate, post-treatment auxiliary procedure rate and complication rate were minimal. It was concluded that in situ ESWL is an effective and safe method for treating certain selected lower ureteric stones and should be considered as a feasible alternative to the more conventional methods of treatment.     

Opioid analgesia during extracorporeal shockwave lithotripsy of gallstones

Gallstone lithotripsy is a new and noninvasive therapeutic option for approximately 20% of patients who harbor cholesterol gallstones. Technologically advanced second-generation lithotripters such as the Dornier MPL 9000 device have greatly simplified biliary lithotripsy with a consecutive reduction in anesthetic requirements. Despite these technical improvements, patients still can experience considerable pain and discomfort during biliary ESWL. Due to its relatively predictable pharmacokinetic profile and its short duration of action, alfentanil appeared to be a suitable drug for pain relief during stone fragmentation. In order to analyze the degree and distribution of pain during gallstone lithotripsy and to evaluate pain control by alfentanil, 44 consecutive patients (ASA I-II) with no previous ESWL therapy were studied. Pain intensity and degree of opioid-induced sedation during shock wave application were evaluated according to 5-point verbal scales that ranged from 0 = no pain to 4 = unbearable pain and 0 = patient awake to 4 = patient asleep. All patients were treated while in the prone position and received oxygen at 6 l/min. After stone focusing, an alfentanil infusion at an initial rate of 2.5 micrograms/kg min was started. Single shock waves were released as test shocks after approximately 2 min. If they were well tolerated, stone fragmentation was begun. If not, more alfentanil was allowed to accumulate until continuous treatment was tolerated. Further in- or decreases of the infusion rate were titrated according to patient response. Registered variables included the required alfentanil loading dose, maintenance and total doses, and the applied shock wave energy approximated by multiplication of shock wave number and voltage squared.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrasonic imaging for extracorporeal shockwave lithotripsy: analysis of factors in successful treatment

The emergence of real-time ultrasonic imaging for extracorporeal shockwave lithotripsy poses questions regarding the factors and techniques which facilitate stone imaging for clinicians with no previous practical experience in ultrasonography. The ability of these clinicians to assess when stone disintegration has been achieved also needs to be confirmed. A wide range of data was recorded from each of 2688 lithotripsy treatments performed over a 2-year period using the EDAP LT.01 ultrasound-imaged piezoelectric lithotriptor. An analysis of these data was performed using a comprehensive microcomputer-based statistics package. The mean time taken for stone imaging and positioning was reduced from 11.2 to 7.5 min over the 2-year period. Obese patients and those with renal pelvic stones were best imaged in a lateral position. Overall there was no difference in percentage stone disintegration or clearance between treatments in the supine or lateral positions, but a significant reduction in the clearance of small caliceal stones resulted when the lateral position was used. Factors associated with a significantly greater percentage of stone disintegration and clearance included pain experienced by the patient during fine adjustment of the processing head during treatment, acoustic focus attenuation and widening and acoustic shadow widening as detected by the urologist at the end of treatment. Among the factors not associated with significant alterations in the percentage of stone disintegration or clearance were the lithotriptor operator, the side or site of the calculus, obesity and shockwave frequency or power. This study confirmed the ability of urologists to develop expertise in ultrasonography for renal stone imaging and to interpret successfully the subtle signs of stone disintegration.     

Salvage extracorporeal shockwave lithotripsy after failed distal ureteroscopy

BACKGROUND AND PURPOSE: When intervention is necessary, controversy remains as to the best treatment modality for stones of the distal ureter. In general, ureteroscopy is favored over extracorporeal shockwave lithotripsy (SWL) as the treatment of choice for distal ureteral stones. Although uncommon, ureteroscopy failures have traditionally necessitated repeat ureteroscopy to retrieve retained stone fragments. We evaluated the efficacy of salvage SWL for failed primary distal ureteroscopy in the community setting. PATIENTS AND METHODS: From December 1989 to December 2000, 6099 patients underwent SWL with the Dornier HM4 lithotripter at our institution. We retrospectively identified 31 patients who had undergone the SWL after a failed distal ureteroscopy. RESULTS: The average stone size in these patients was 9.4 mm, the average time interval from ureteroscopy to SWL was 17.2 days, and the average number of shockwaves delivered was 2386. All patients had had stents placed after ureteroscopy. Twenty-seven patients (87%) had resolution of their stone burden after one SWL session. The remaining four patients underwent additional procedures. CONCLUSIONS: Ureteroscopy is an effective modality for the treatment of distal ureteral stones. However, when unsuccessful, a salvage procedure may be necessary. Extracorporeal lithotripsy is a less invasive procedure with comparable success rates in the distal ureter. This report suggests that salvage SWL is an appropriate option for patients in whom distal ureteroscopic stone extraction fails.     

Pressure-release versus rigid reflector for extracorporeal shockwave lithotripsy

PURPOSE: To evaluate the advantages and disadvantages of using a pressure-release reflector instead of a rigid reflector to concentrate shockwaves for extracorporeal shockwave lithotripsy (SWL). MATERIALS AND METHODS: As in all electrohydraulic lithotripters, shockwaves were generated by electrical breakdown of water between two electrodes, located at the focus (F1) closest to a paraellipsoidal reflector. A pressure-release reflector, made out of polyurethane foam, was constructed and tested on a research lithotripter using kidney stone models. Fragmentation data and pressure measurements were compared with those of a conventional rigid reflector tested on the same device. RESULTS: The weight of stone model fragments remaining after shockwave exposure was less with the pressure-release reflector after screening through a 3.0 x 3.0-mm mesh. The residual fragment weight was less with the rigid reflector using 1.0 x 1.0- and 0.6 x 0.6-mm meshes. CONCLUSION: Pressure-release reflectors may maintain acceptable stone fragmentation while offering improved patient safety and should be considered for SWL.     

Cardiac dysrhythmias induced by extracorporeal shockwave lithotripsy.

PATIENTS AND METHODS: We evaluated in 269 consecutive patients the incidence and gravity of dysrhythmic complications during nonsynchronized extracorporeal shockwave lithotripsy (SWL) using an electromagnetic lithotripter. RESULTS: Dysrhythmia occurred during treatment in 22 patients (8.8%) with no previous cardiac dysrhythmia. Ventricular extrasystoles occurred in 14 patients, atrial extrasystoles in 7 patients, and sinus bradycardia in 1 patient. It was not necessary to terminate treatment because of the occurrence of dysrhythmia in any of the patients. For 13 of the 22 patients (59%), it was sufficient to interrupt the treatment momentarily to obtain resumption of the normal rhythm. For 8 patients (36%), treatment was continued after triggering the release of the shockwaves with the refractory phase of the heart cycle. For one case of bradycardia (42 beats/min), it was possible to continue with the treatment after intravenous administration of atropine 0.5 mg. Pretreatment dysrhythmias were revealed by the electrocardiographic examination in 16 of the patients studied (6.3%). CONCLUSIONS: Extracorporeal shockwave lithotripsy without ECG triggering has been found to be fast and efficient and not correlated with the occurrence of dysrhythmic episodes of any particular clinical significance. No significant correlation was found between the occurrence of dysrhythmia, the side treated, the number and strength of the shockwaves, or the administration of analgesics. It was found, however, that dysrhythmia occurred almost exclusively in treatments involving the kidneys. The ECG-triggering option was indispensable in some patients in order to complete the lithotripsy without complications.     

Optimal treatment for distal ureteral calculi: extracorporeal shockwave lithotripsy versus ureteroscopy

BACKGROUND: The optimal treatment for distal ureteral calculi remains controversial. We present data from our institution to compare the efficacy of extracorporeal shockwave lithotripsy (SWL) and ureteroscopy with different lithotripsy modalities (URSL). METHODS: From January 1994 to September 1997, 954 distal ureteral calculi were treated at our institution using in situ SWL (Siemens Lithostar) in 524 patients and ureteroscopy (Wolf 8.0F instrument and Swiss Lithoclast) in 430 patients. Stone sizes and patient ages were similar in these two groups. RESULTS: In the SWL group, the 3-month stone-free rate was 87%, and the effectiveness quotient (EQ) was 68.7%. In the URSL group, there was a 96% stone-free rate with an EQ of 92.1%. The SWL treatment was more expensive than URSL. CONCLUSION: At our institution, ureteroscopy is more efficacious than SWL for the treatment of distal ureteral calculi. In selected patients who had stones >10 mm with evidence of impaction and severe colic pain, we strongly suggest that URSL is the best choice.     

Use of high frequency jet ventilation in extracorporeal shockwave lithotripsy

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.