Extracorporeal Shock Wave Lithotripsy

Application of extracorporeal shock wave therapy in nervous system diseases: A review

Neurological disorders are one of the leading causes of morbidity and mortality worldwide, and their therapeutic options remain limited. Recent animal and clinical studies have shown the potential of extracorporeal shock wave therapy (ESWT) as an innovative, safe, and cost-effective option to treat neurological disorders. Moreover, the cellular and molecular mechanism of ESWT has been proposed to better understand the regeneration and repairment of neurological disorders by ESWT. In this review, we discuss the principles of ESWT, the animal and clinical studies involving the use of ESWT to treat central and peripheral nervous system diseases, and the proposed cellular and molecular mechanism of ESWT. We also discuss the challenges encountered when applying ESWT to the human brain and spinal cord and the new potential applications of ESWT in treating neurological disorders.

Effects of Roughly Focused Extracorporeal Shock Waves Therapy on the Expressions of Bone Morphogenetic Protein-2 and Osteoprotegerin in Osteoporotic Fracture in Rats

BACKGROUND

Roughly focused extracorporeal shock waves therapy (ESWT) is characterized by a wide focal area, a large therapy zone, easy positioning, and less pain during treatment. The purpose of this study was to investigate the effects of roughly focused ESWT on the expression of osteoprotegerin (OPG) and bone morphogenetic protein-2 (BMP-2) in osteoporotic fractures in rats.

METHODS

Seventy-two female Sprague-Dawley (SD) rats, 3 months old, were divided into sham-operated group (n = 6) and an ovariectomized (OVX) group (n = 66). Sixty OVX SD rats were used as a model of double proximal tibial osteotomy and inner fixation. The osteotomy site in the left tibia was treated with roughly focused ESWT once at an energy density of 0.26 mJ/mm2, 60 doses/min, and 2000 pact quantities. The contralateral right tibia was left untreated and served as a control. Expression of OPG and BMP-2 in the callus of the osteoporotic fracture area was assessed using immunohistochemistry, real-time polymerase chain reaction (PCR), and Western blotting analysis.

RESULTS

Bone mineral density (BMD) at the proximal tibia, femur, and L5 spine was significantly reduced after ovariectomy. BMD of proximal tibia was 12.9% less in the OVX group than that in the sham-operated group. Meanwhile, bilateral oophorectomy resulted in a lower trabecular bone volume fraction (BV/TV) in the proximal tibia of the sham-OVX animals. Three months after bilateral oophorectomy, BV/TV was 14.29% of baseline BV/TV in OVX legs versus 45.91% in the sham-OVX legs (P < 0.001). These data showed that the SD rats became a suitable model of osteoporosis, 3 months after they were OVX. Immunohistochemical analysis showed higher levels of BMP-2 and OPG expression in the treatment group than those in the control group. Compared with the contralateral controls, decreased expression of OPG and BMP-2 at 3 days after roughly focused ESWT, followed by a later increase at 7 days, was indicated by real-time PCR and Western blotting analysis. The OPG messenger RNA (mRNA) expression levels peaked at 6 weeks after the shock wave treatment, paired with a much earlier (at 4 weeks) increase of BMP-2, and declined close to normal at 8 weeks.

CONCLUSIONS

Roughly focused ESWT may promote the expression of OPG and BMP-2 in the osteoporotic fracture area in rats. BMP-2 and OPG may act synergistically and may lead to a significant enhancement of bone formation and remodeling.

Comparison of ESWL and ureteroscopic holmium laser lithotripsy in management of ureteral stones

Background

There are many options for urologists to treat ureteral stones that range from 8 mm to 15 mm, including ESWL and ureteroscopic holmium laser lithotripsy. While both ESWL and ureteroscopy are effective and minimally invasive procedures, there is still controversy over which one is more suitable for ureteral stones.

Objective

To perform a retrospective study to compare the efficiency, safety and complications using ESWL vs. ureteroscopic holmium laser lithotripsy in management of ureteral stones.

Methods

Between October 2010 and October 2012, 160 patients who underwent ESWL or ureteroscopic holmium laser lithotripsy at Suzhou municipal hospital for a single radiopaque ureteral stone (the size 8–15 mm) were evaluated. All patients were followed up with ultrasonography for six months. Stone clearance rate, costs and complications were compared.

Results

Similarity in stone clearance rate and treatment time between the two procedures; overall procedural time, analgesia requirement and total cost were significantly different. Renal colic and gross hematuria were more frequent with ESWL while voiding symptoms were more frequent with ureteroscopy. Both procedures used for ureteral stones ranging from 8 to 15 mm were safe and minimally invasive.

Conclusion

ESWL remains first line therapy for proximal ureteral stones while ureteroscopic holmium laser lithotripsy costs more. To determining which one is preferable depends on not only stone characteristics but also patient acceptance and cost-effectiveness ratio.

Analyzing the effect of distance from skin to stone by computed tomography scan on the extracorporeal shock wave lithotripsy stone-free rate of renal stones

Purpose

To determine whether the distance from skin to stone, as measured by computed tomography (CT) scans, could affect the stone-free rate achieved via extracorporeal shock wave lithotripsy (ESWL) in renal stone patients.

Materials and Methods

We retrospectively reviewed the records 573 patients who had undergone ESWL at our institution between January 2006 and January 2010 for urinary stones sized from about 5 mm to 20 mm and who had no evidence of stone movement. We excluded patients with ureteral catheters and percutaneous nephrostomy patients; ultimately, only 43 patients fulfilled our inclusion criteria. We classified the success group as those patients whose stones had disappeared on a CT scan or simple X-ray within 6 weeks after ESWL and the failure group as those patients in whom residual stone fragments remained on a CT scan or simple X-ray after 6 weeks. We analyzed the differences between the two groups in age, sex, size of stone, skin-to-stone distance (SSD), stone location, density (Hounsfield unit: HU), voltage (kV), and the number of shocks delivered.

Results

The success group included 33 patients and the failure group included 10. In the univariate and multivariate analysis, age, sex, size of stone, stone location, HU, kV and the number of shocks delivered did not differ significantly between the two groups. Only SSD was a factor influencing success: the success group clearly had a shorter SSD (78.25±12.15 mm) than did the failure group (92.03±14.51 mm). The results of the multivariate logistic regression analysis showed SSD to be the only significant independent predictor of the ESWL stone-free rate.

Conclusions

SSD can be readily measured by CT scan; the ESWL stone-free rate was inversely proportional to SSD in renal stone patients. SSD may therefore be a useful clinical predictive factor of the success of ESWL on renal stones.

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

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.

Retroperitoneal laparoscopic pyelolithotomy: how does it compare with percutaneous nephrolithotomy for larger stones?

Our 10-year experience of retroperitoneal laparoscopic pyelolithotomy, a rarely performed minimally invasive operative procedure, is presented. The results are compared with our own experience of percutaneous nephrolithotomy for larger renal stones. Forty-two patients with a mean age of 39.12 years underwent 43 retroperitoneal laparoscopic pyelolithotomies using Gaur's balloon technique. The total number of stones was 65 (44 pelvic and 21 calyceal) and they ranged in size between 5 and 48 mm. Two patients had chronic renal failure due to bilateral impacted renal calculi. Forty-eight percutaneous nephrolithotomies performed in the same unit during the last 2 years in patients with non-staghorn calculi > 2 cm were included for a comparative study. The open conversion rate and the drainage period for retroperitoneal laparoscopic pyelolithotomy were much higher. However, the operative time, blood loss, analgesic intake, hospital stay, residual stone rate, re-treatment rate and major complication rates were lower, compared with percutaneous nephrolithotomy.

Treatment of renal calculi by lithotripsy: minimizing short-term shock wave induced renal damage by using antioxidants

Treatment with extracorporeal shock wave lithotripsy (ESWL), the preferred method of treating kidney stones <3 cm in size, has been shown to induce silent and often self-limiting acute and chronic lesions in the kidneys and adjacent organs. We conducted a randomized clinical trial to determine whether ESWL produces ischaemia and reperfusion injury in the kidneys and whether oral administration of antioxidants reduces the degree of short-term renal injury in patients treated with ESWL. The study included 120 patients with renal stones (1-3 cm in size) treated with ESWL. The patients were divided into three groups--patients in group A (n=39) served as a control group and were not given any antioxidants; patients in group B (n=41) were given two capsules of antioxidants "Nature Made R: " 2 h before ESWL, and 2 and 8 h after ESWL; and patients in group C (n=40) were given two capsules of the antioxidants 2 and 8 h after ESWL. Double 'J' stents were inserted in patients before treatment with ESWL. Blood and urine samples were obtained from all patients just before the start of treatment with ESWL, and at 2 and 24 h and on 7th and 28th day after ESWL. Serum levels of malondialdehyde (MDA), alpha-tocopherol, cholesterol, albumin and ascorbic acid, and alpha-tocopherol/cholesterol ratio were determined. Urinary levels of albumin and beta(2) microglobulin were also determined as measures of renal tubular injury. At 24 h after ESWL, patients given antioxidants (groups B + C) had significantly reduced mean serum concentration of MDA (P<0.001); higher levels of serum ascorbic acid (P<0.001) and serum albumin (P<0.001); lower alpha-tocopherol/cholesterol ratio, lower urinary albumin and beta(2 )microglobulin levels compared with patients who did not receive antioxidants (group A). These findings suggest that treatment with ESWL generates free radicals through ischaemic/reperfusion injury mechanism, and that oral administration of antioxidant may protect these patients from short term renal injury caused by ESWL.

Evaluation of the effects of nephrotomy on renal function in clinically normal cats

OBJECTIVE

To evaluate the effects of nephrotomy on renal function in clinically normal cats.

ANIMALS

20 specific-pathogen-free, 9- to 11-month-old female mixed-breed cats.

PROCEDURE

Serum chemistry analyses, CBC determinations, urinalyses, microbiologic urine cultures, renal ultrasonography, abdominal radiography, and single-kidney and total glomerular filtration rate (GFR) determinations by use of renal scintigraphy and measurements of plasma disappearance of technetium 99m-diethylenetriaminepentaacetic acid were performed before surgery and at 3, 12, 26, 52, and 78 weeks after surgery in 10 cats that underwent unilateral nephrotomy and in 10 control cats that underwent a sham surgical procedure.

RESULTS

Two cats (1 from each group) did not complete the study, and their data were eliminated from analyses. Unilateral nephrotomy resulted in a 10% to 20% reduction in mean single-kidney GFR, compared with that of nephrotomy contralateral control kidneys. However, mean total GFR in nephrotomy-group cats was not significantly different from that of sham-group cats. Over the 78 weeks of study, mean total GFR declined 34% and 40% in nephrotomy- and sham-group cats, respectively. Adverse events associated with nephrotomy included persistent microscopic hematuria, renal pelvis hyperechogenicity with distant shadowing on ultrasonographic evaluation, dilatation of renal pelves, and hydronephrosis.

CONCLUSIONS AND CLINICAL RELEVANCE

Nephrotomy in normal functioning feline kidneys results in a modest relative reduction in renal function, compared with contralateral kidney controls, but has minimal effect on total GFR when compared with sham-operated control cats. However, any detrimental effects of nephrotomy may be magnified in cats with diseased kidneys, which may have little or no capacity for repair or compensation.

The use of shock wave lithotripsy for renal calculi

PURPOSE OF REVIEW

Shock wave lithotripsy has been considered a mainstay of therapy for renal calculi for the last 20 years. Shock wave lithotripsy is noninvasive and requires the least anesthesia of the treatment modalities for treatment of renal calculi and therein lies its popularity. In the last decade, however, there have been changes in thinking regarding methods of patient selection for shock wave lithotripsy, changes in the technique of the existing shock wave lithotriptors and new technologies designed to increase the efficacy of shock wave lithotriptors.

RECENT FINDINGS

New studies have shown that shock wave lithotripsy may be less effective than other modalities for treating lower pole stones. Other existing technologies, such as computerized tomography, are being used to more effectively select patients for shock wave lithotripsy. Ongoing studies are evaluating changing the shock wave rate to increase stone fragmentation. In addition, efforts are being made to improve lithotripsy by designing more effective lithotriptors.

SUMMARY

Shock wave lithotripsy has become a widely used modality for treating renal calculi due to its noninvasive nature and ease of application. Although success rates are reasonable, there is room for improvement. With appropriate patient selection, significant improvements in stone-free rates may be achieved. It is anticipated that, with further research, improvements in lithotriptor design will result in higher treatment success rates with reduced renal trauma and improved patient comfort.

Evaluation of Synchronous Twin Pulse Technique for Shock Wave Lithotripsy: Determination of Optimal Parameters for In Vitro Stone Fragmentation

PURPOSE

The Twinheads extracorporeal shock wave lithotriptor (THSWL) is composed of 2 identical shock wave generators and reflectors. One reflector is under the table and the other is over the table with a variable angle between the axes of the 2 reflectors. The 2 reflectors share a common second focal point, making it possible to deliver an almost synchronous twin pulse to the targeted stone. We studied the optimal parameters for in vitro stone fragmentation.

MATERIALS AND METHODS

Two types of 1 cm artificial stones were used, namely Bon(n)-stones of 3 compositions (75% calcium oxalate monohydrate [COM] plus 25% uric acid, struvite and cystine) and plaster of Paris. The parameters tested were shock wave number (100, 500 and 1,000), shock wave power (8, 11 and 14 kV) and angle between the reflector axes (67, 90 and 105 degrees). After the optimal parameters were determined we studied the disintegrative efficacy of THSWL for 3 types of human urinary calculi, including COM, calcium hydrogen phosphate (brushite) and cystine. Each stone received 1,000 twin shock waves at 14 kV with an angle of 90 degrees between the reflectors. All experiments were done using a rate of 60 twin shock waves per minute. Following lithotripsy stone fragments were processed and sized. The ratio of the weight of fragments greater than 2 mm-to-total weight of all fragments was calculated.

RESULTS

Optimal stone fragmentation results for THSWL were obtained with the maximum number of shock waves (1,000) and full power (14 kV). There was no significant statistical difference in fragment size or the ratio of fragments greater than 2 mm with the use of different angles except for cystine and plaster of Paris calculi, for which the right angle was most effective. At application of the optimal parameters to human stones THSWL produced small fragment size for COM and cystine stones, while brushite stones were not fragmented to the same extent.

CONCLUSIONS

The efficacy of synchronous twin pulse technology improves as the number of shock waves and power increase. A 90-degree angle between the shock wave reflectors is advantageous for certain stones (that is cystine and plaster of Paris) but it is not a factor for other stone compositions. THSWL has satisfactory disintegrative efficacy for human stones, especially COM and cysteine calculi.

Synchronous twin-pulse technique to improve efficacy of SWL: preliminary results of an experimental study

BACKGROUND AND PURPOSE

Extracorporeal shockwave lithotripsy (SWL) is the treatment of choice for the majority of renal and ureteral stones. The Dornier HM3 lithotripter has good results but with some limitations and complications. A number of second- and third-generation machines have been developed employing different energy sources, focusing devices, and coupling media. These devices overcome some of the limitations and lessen the complications but at the expense of the success rate. Use of the consecutive double-pulse technique (as in the MFL 5000) and of combined under-table and over-table modules consecutively (as in the Siemens Lithostar Plus) improves the efficacy of fragmentation. The aim of this study was to study the effects of the use of synchronous twin pulses generated by under-table and over-table identical shockwave reflectors for stone fragmentation.

MATERIALS AND METHODS

We designed a lithotripter with two identical shockwave generators and identical reflectors (twin heads). One reflector was under the table and fixed, while the second reflector was over the table and hangs on a C-arm so that the angle between the axes of the two reflectors could be changed. The second focal points (F2) of the two reflectors lay in the same position. A lucent lightweight acrylic water tank with one side sealed by a silicon rubber membrane was fixed to the SWL table so that the membrane coupled with the water cushions of both reflectors. The tank was filled with degassed water and the targeted material was fixed on a holder and immersed in the water so as to be at F2. Comparison of the use of one shockwave source and two shockwave sources simultaneously was done relative to: (1) cavitation effect on aluminum foil; (2) quality of disintegration, shape of the focal zone, and ideal position of F2 using ceramic blocks; and (3) disintegrative efficacy using dental bone cement.

RESULTS

The cavitation effect became more localized with the use of two reflectors. Also, the volume and rate of stone disintegration increased with the use of the two reflectors, with production of fine (<2-mm) fragments. The focal zone became smaller and conical with no propagation of shockwaves beyond F2. These results were more evident if the angle between the axes of the reflectors was 90 degrees.

CONCLUSION

This new technique of SWL may improve the efficacy of treatment of urinary tract stones. It also may be less harmful to the renal tissues, but animal experiments must be carried out to prove this.

Extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy

This article reviews the basic anesthetic considerations for ESWL and PCNL. General principles governing the operation of lithotripters, elements of treatment that impinge on safety, and effective intraoperative anesthesia and complications that may be encountered in the perioperative period are discussed. Factors influencing blood loss and concerns arising from positioning patients prone are addressed in the sections devoted to PCNL.

Changes in resistive index following extracorporeal shock wave lithotripsy

BACKGROUND

Extracorporeal shock wave lithotripsy (ESWL) has replaced most surgical and endourologic forms of therapy for upper urinary tract stone disease. Despite its proved safety and efficacy, its adverse effects on renal function are still to be identified. A newer diagnostic technique, color Doppler ultrasonography, has brought a new insight into renal function. It enables precise evaluation of the renal vascular supply. Changes in intrarenal vascular resistance after ESWL were studied with Doppler ultrasound techniques.

METHODS

In 70 consecutive patients the resistive index (RI) was measured at an interlober artery before and 30 min after ESWL in the treated and contralateral kidneys. In 17 patients, a follow-up Doppler study was performed 1 week after ESWL.

RESULTS

In the treated kidneys, the RI significantly increased from 0.656+/-0.053 (mean +/- SD) at baseline to 0.682+/-0.053 (P<0.0001). There was no significant correlation of increase in RI with patient age (r = 0.010) or with pre-ESWL blood pressure (r = 0.002). Elderly patients (> or =60 years old, n = 31) had higher RI levels on baseline than younger patients (<60 years old, n = 39). In 18 of the 31 (58.1%) elderly cases the RI were elevated to greater than 0.7, indicating pathologic changes. In younger patients, only 9 (23.1%) experienced increase in RI up to 0.7 or greater. The contralateral untreated kidneys showed significant change in RI before (0.664+/-0.045) and after (0.679+/-0.049) lithotripsy in elderly patients (P<0.005). A follow-up Doppler study showed that the mean RI returned to pretreatment levels after 1 week.

CONCLUSIONS

Because of higher RI levels on baseline, elderly patients have a higher risk of post-ESWL renal tissue damage than younger patients. Clinical implication of RI change in the contralateral kidneys in this study remains to be answered. The measurement of changes in RI with Doppler ultrasound techniques after ESWL may provide useful information for clinical diagnosis of renal tissue damage.

Helical CT of urinary tract stones. Epidemiology, origin, pathophysiology, diagnosis, and management

Urolithiasis is a common medical problem. The diagnosis of this entity in the setting of acute flank pain presents an interesting challenge to the radiologist. Unenhanced helical CT has recently entered the fray and has quickly become the imaging study of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. The nature and origin of ureteral stones and the pathophysiology of ureteral obstruction provide a basis for understanding the imaging findings in these patients.

Effects of single-shot and twin-shot shockwaves on urinary enzyme concentrations

BACKGROUND AND OBJECTIVE

Extracorporeal shockwave lithotripsy (SWL) remains the first-line treatment of urinary calculi. However, a number of studies have shown that adverse effects on the kidneys and the surrounding tissues may be encountered in short- and long-term follow-up. The aim of this study was to compare the effects of single-shot and twin-shot SWL techniques to identify the safest modality in terms of urinary enzyme excretion.

PATIENTS AND METHODS

In this prospective, investigator-blinded, randomized study, urinary enzymes, beta2-microglobulin, microalbumin, Na, K, Ca, and creatinine concentrations were analyzed in 59 consecutive patients. Measurements were performed in urine specimens collected immediately before and after the SWL procedure and also on the 3rd and 7th days after treatment, which was performed on a Dornier MFL-5000 lithotripter utilizing the twin-shot technique (Group 1; N = 30) or the single-shot technique (Group 2; N = 29) with 3000 shockwaves at 18 kV per treatment.

RESULTS

Although there was no statistically significant difference in the results between the groups, urinary levels of microalbumin, alanine and aspartate aminotransferases, beta-2-microalbumin, gamma-glutamyltranspeptidase, Na, K, and Ca rose acutely after SWL, reaching maximum levels on the 3rd day, and returned to the baseline by the 7th day following the treatment in both groups.

CONCLUSION

This study demonstrates that SWL performed by either a single-shot or twin-shot shockwave technique has a transient detrimental effect on renal function, as assessed by urine enzyme concentrations. It is recommended that the twin-shot shockwave technique be used in routine lithotripsy in consideration of the cost-effectiveness provided by the shorter treatment time.

Experience with the Dornier lithotriptor MPL 9000-X for the treatment of vesical lithiasis

Between February 1994 and March 1995, 52 patients (48 men and 4 women) with vesical lithiasis were treated by extracorporeal shock wave lithotripsy (ESWL), using the MPL 9000-X Dornier lithotriptor. Twenty-five patients showed bladder outlet obstruction. In 9 patients, there was evidence of associated bladder neuropathy. In 6 patients, calculi presented idiopathically in normal bladders. Two patients had silent migration of ureteral calculi and increase in bladder volume, 8 were high risk and 2 others refused other methods of up to date treatment. Vesical stone sizes ranged from 10 to 22 mm in greatest diameter (mean 15 mm). The treatments were performed without the use of anaesthesia and on an outpatient basis. Complete fragmentation was achieved after a single session in 46 patients and 3 required 2 sessions. Postoperative adjunctive endourological procedures included cystoscopy in 9 patients and urethroscopy in 1 patient for evacuation of stone fragments. The overall stone-free rate was 94.2% (49 out of 52 patients) with ESWL and adjunctive measures as needed. No major complications were noted. We find ESWL with the MPL 9000-X lithotriptor to be a simple, effective and safe modality for the treatment of most patients with vesical lithiasis, especially in high risk patients.

Electrohydraulic and extracorporeal shock-wave lithotripsy

The literal meaning of lithotripsy is the "act of breaking stones." There are two forms of lithotripsy available for use in veterinary medicine: electrohydraulic shock-wave lithotripsy (EHL) and extracorporeal shock-wave lithotripsy (ESWL). With EHL, a shock-wave is generated immediately adjacent to a urolith within the urinary bladder. In dogs, nephroliths or ureteroliths can be successfully treated with ESWL. With ESWL, the shock-waves are generated outside the body and directed toward the urolith.

Detection of source of haematuria after extracorporeal shock wave lithotripsy (ESWL) by automated measurement of urinary red cell volume

Midstream urine samples taken from 35 patients with secondary haematuria due to nephrolithiasis and 31 patients with haematuria after ESWL were compared using a red cell analyser (RCA) to differentiate the source of haematuria. Urine samples obtained from both groups were examined by RCA for urinary red cell mean corpuscular volume (UMCV) and urinary red cell volume distribution curves (RCVDC). To rule out the influence of blood MCV (BMCV), BMCVs were determined separately and the ratio of UMCV/BMCV (R) was calculated. Although our findings showed no difference between haematurias after ESWL and nephrolithiasis, we cannot exclude a direct effect of shock waves on renal tissue.

Laboratory and clinical assessment of pneumatically driven intracorporeal lithotripsy

A pneumatically driven intracorporeal lithotripter (the Swiss Lithoclast) has recently been approved for use in the United States. We compared its performance in vitro with ultrasonic, electrohydraulic and laser lithotripsy devices using a standard plaster-of-Paris stone phantom. The probe sizes and output settings were identical to those used during clinical treatment. The fragmentation efficiency index (measured as the lithotripsy time needed to reduce the stone phantom to particles <2 mm divided by the initial stone weight) ranged from 5.0 to 8.5 min/g of stone mass, with this value increasing from pneumatic to electrohydraulic to laser and to ultrasonic lithotripsy. We also performed an objective study in a swine model, which showed no adverse consequence of pneumatic lithotripsy. Finally, we evaluated our initial 41 patients who had undergone pneumatic stone fragmentation. We treated 8 patients having 11 renal calculi, 30 patients having 37 ureteral calculi, and 3 patients having 6 bladder calculi employing pneumatic probes ranging in size from 0.8 to 2.0 mm. Stone fragmentation was successful in a single session in 95% of the ureteral calculi and 100% of both renal and bladder calculi. Stone analysis in 23 patients revealed 17 (74%) calcium oxalate monohydrate and 1 (4%) cystine calculi. Our clinical and laboratory assessment of this newly developed pneumatic lithotripsy device further validates its efficacy in fragmenting stone of all compositions and its overall safety associated with clinical application.

Cardiac arrhythmias with external fixed-rate signal generators in shock wave lithotripsy with the Medstone lithotripter

OBJECTIVES

To evaluate the incidence and outcome of cardiac arrhythmias associated with an external fixed-rate generator and the Medstone lithotripter with regard to stone location, anesthesia type, patient age, and gender.

METHODS

Data were obtained on 933 patients who underwent shock wave lithotripsy (SWL) with the Medstone lithotripter. Patients were randomly divided into two study groups, including those with pre-existing cardiac disease, hypertension, and cardiac medications. Group 1 (576 patients) were treated with the external fixed-rate signal generator (cardiac simulator). Group 2 (357 patients) underwent electrocardiogram-gated SWL (no simulator). All patients were monitored for arrhythmias during SWL. Patients who developed arrhythmias on the simulator were converted to gated SWL.

RESULTS

In group 1, 463 patients (80%) had no arrhythmias during treatment, whereas 113 patients (20%) developed cardiac arrhythmias (primarily premature ventricular contractions [PVCs]) and were successfully converted to gated SWL. Only 1 patient in group 2 (0.3%) had a documented arrhythmia (PVC). Group 1 patients who developed arrhythmias with a cardiac simulator were more likely to have renal rather than ureteral stones. Chi-square analysis showed a significant correlation between patients with and without arrhythmias in group 1 with regard to stone location (P <0.0001). In group 1, regional anesthesia, intravenous anesthesia, and general anesthesia had an arrhythmia rate of 14%, 27%, and 38%, respectively. The only patient in group 2 who developed arrhythmias was under general anesthesia. The differences between groups 1 and 2, with regard to anesthesia type and arrhythmia, were statistically significant (P <0.001). No patients required additional medical therapy or hospitalization for cardiac events, and all patients safely completed the SWL treatment.

CONCLUSIONS

With careful monitoring and adequate precautions, external fixed-rate signal generators are safe, effective methods for pacing the Medstone shock wave lithotripter and probably other extracorporeal shock wave lithotripters.

Intracorporeal pneumatic lithotripsy for ureteral and vesical calculi

To evaluate the effectiveness of pneumatic lithotripsy, 92 patients with 98 lower or mid-ureteric calculi and 8 with vesical calculi were treated with pneumatic lithotripsy (Swiss Lithoclast) under spinal anaesthesia. Successful stone fragmentation was achieved in 96 patients. In two patients their stones migrated to the upper ureter and renal pelvis during the procedure and so they were referred for extra corporeal shock wave lithotripsy. Total ureteral avulsion occurred in one patient and in another case attempts to dilate the stenotic ureteral orifice failed. In both cases, ureterolithotomy and ureteral reimplantation were performed. Pneumatic lithotripsy is found to be an easy, reliable and cost-effective method of endoscopic lithotripsy.

Extracorporeal shockwave lithotripsy for urinary calculi in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited systemic disorder. Renal stones have a high rate of occurrence among patients with ADPKD and are a significant cause of morbidity in this disorder. Thirteen patients with ADPKD and symptomatic or obstructive renal stones presented to our hospital for evaluation and treatment with extracorporeal shockwave lithotripsy (SWL). A total of 16 renal units were treated. The auxiliary procedures included placement of a double-J stent in nine kidneys when the stone was larger than 8 mm in diameter. Eleven patients (85%) were stone free 3 months after lithotripsy; a second treatment was necessary in two patients. We conclude that SWL can be used as a primary management tool for renal stones in patients with ADPKD.

Stone disintegration: effect of shock wave projection and electrode age on this parameter in a standard stone model

Despite the real effectiveness and successful results of shock wave application, the effect of some varying parameters, namely number of shock wave (SW) electrical discharge value (kV), projection of the shock waves and electrode age are still to be evaluated. By using a standard stone model, we evaluated the real effect of the projection of shock waves and electrode age on the degree of stone disintegration. Our results indicated no significant relationship between the kV value and the degree of stone disintegration. However, as the number of SW increased, the rate of disintegration became evident. On the other hand, application of the same number of SW from two different angles revealed more effective disintegration rate on standard stone model. Thus SW number, age of the electrode and the projection of shock waves seemed to be important in the disintegration of the stones.

Enzymatic evaluation of renal damage caused by different therapeutic procedures for kidney stone disease

In an attempt to evaluate renal injury relative to open surgery, percutaneous nephrolithotripsy (PCN) and extracorporeal shock wave lithotripsy (ESWL) were studied in 52 patients with renal calculus disease. Preoperative and postoperative urinary levels of N-acetyl-glycosaminidase (NAG), a sensitive marker of renal tubular damage, were studied. No significant changes were noted in posttreatment urinary NAG values among patients who underwent ESWL or PCN. Although statistically nonsignificant, a constant mild increase of urinary NAG was observed after PCN, that has to be evaluated with long-term follow-up studies. The shock wave number or power in cases treated with ESWL as well as the number of renal punctures in the PCN group did not change the effect on renal tubular function. Diabetics and patients with chronic renal disease treated by ESWL did not show any significant change in posttreatment urinary NAG levels. In contrast to that, all patients treated by open surgery had significant, intense and prolonged increase of the postoperative NAG values, especially those treated by ischaemic nephrolithotomy. Comparing the three different therapeutic modalities, open surgical procedures had the most significant effect on renal function and this difference was statistically significant. We therefore suggest that ESWL does not endanger renal function, while open surgery must be reserved for selected cases.

The management of upper urinary tract calculi by piezoelectric extracorporeal shock wave lithotripsy in spinal cord injury patients

From May 1988 to September 1994, 15 spinal cord injury patients were treated by piezoelectric extracorporeal shock wave lithotripsy. Aged from 23 to 71 years (mean = 39), they presented with a total of 23 stones, of which 18 were located in the calyces, three in the renal pelvis and two in the proximal ureter. The maximum dimensions of calculi varied from 5 to 35 mm (mean = 11). Patients were placed in a dorsal decubitus position during the sessions, three being sedated with diazepam, while the other 12 remained unsedated. All were treated routinely with systemic antibiotics. Auxiliary procedures consisted of two pyelocalyceal flushings, three double J ureteral stenting and three ureteroscopies with fragment removal with a Dormia basket. No episode of autonomic dysreflexia was observed. Short term side effects were limited to a few cases of gross haematuria which regressed spontaneously. Overall, eight successes (53%), and seven failures (47%), were registered. Of the failures, one was the result of a partial fragmentation, while six were related to intrarenal retention of residual fragments resulting in four cases in rapid recurrences. Extracorporeal shock wave lithotripsy can be easily applied to spinal cord injury patients. Its usefulness and limitations need to be well understood and a global consideration must be applied to the prevention and early detection of the upper urinary calculi in this exposed population of patients.

Intracorporeal lithotripsy with the Swiss lithoclast

OBJECTIVE

To evaluate the use of the Swiss lithoclast in the management of urinary calculi.

PATIENTS AND METHODS

Between January and November 1993, 60 patients with a total of 61 urinary calculi were treated with the Swiss lithoclast. Forty patients had a ureteric calculus, two had a ureterocele with a calculus, one a steinstrasse, 16 a vesical stone and two a urethral calculus. Eighty per cent of patients were treated on a day-care basis.

RESULTS

Fragmentation of the urinary calculi was successful in 59 of the 60 patients. Both patients with a urethral calculus and 15 of 16 with a vesical calculus were stone-free after the procedure. All those with a ureteric calculus were stone-free at 6 weeks. There were no intra-operative or long-term complications directly related to the use of the Swiss lithoclast.

CONCLUSION

The results of this study show that the Swiss lithoclast is a simple, safe, reliable and economical method of endoscopic lithotripsy for the treatment of urinary tract calculi. Although the lithoclast's use is limited to rigid or semi-rigid endoscopes there is now a suction facility for the immediate removal of small stone fragments.

Extracorporeal shockwave lithotripsy in anomalous kidneys

Traditionally, stones in anomalous kidneys have been removed by open or percutaneous surgery. Extracorporeal shockwave lithotripsy (SWL) with the Dornier MPL 9000 lithotripter was performed in seven patients with horseshoe kidneys, four with pelvic ectopic kidneys, and six with malrotated kidneys. Twelve patients (71%) needed repeated treatments. A total of 11 patients (65%) in all the groups were stone free, and four patients had asymptomatic residual fragments no more than 5 mm in diameter. In the remaining two patients, no sign of stone disintegration was observed, and they underwent open surgery. Extracorporeal lithotripsy is the treatment of choice for stones in horseshoe or malrotated kidneys but is not useful for stones in most pelvic kidneys.

Extracorporeal shock wave lithotripsy for ureteric calculi with the Dornier MFL5000 lithotriptor at a multi-user centre

We have reviewed 241 consecutive cases of ureteric calculi managed with the Dornier MFL5000 lithotriptor. The patients were individually managed by 24 visiting urologists between October 1990 and September 1991. There were 153 cases of upper ureteric calculi, of which 59 were successfully manipulated back to the renal pelvis prior to treatment, and 94 were treated in situ. There were 27 mid-ureteric and 61 lower ureteric cases; in 51% of stones treated in situ ureteric stents were placed prior to extracorporeal shock wave lithotripsy. All stones were radio-opaque and localised with on-line fluoroscopy. The outcome of treatment was assessed at 3 months, with failure defined as residual calculi > or = 4 mm. The follow-up rate was 89%. The overall fragmentation rate after a single treatment was 72%, which increased to 81% with re-treatment. Of the upper ureteric calculi, manipulated stones had a significantly higher fragmentation rate (85%) compared with in situ stones (63%). The fragmentation rate was 89% for mid-ureteric stones and 71% for lower ureteric stones. Factors that significantly influenced fragmentation were retrograde manipulation of stone, number of impulses delivered and age of the patient. Stone size, the presence of a ureteric stent and mode of anaesthesia did not significantly influence fragmentation. These results suggest the Dornier MFL5000 lithotriptor is effective for the management of ureteric calculi in a multi-user setting.

Recovery room risk and outcome associated with renal extracorporeal shock wave lithotripsy

STUDY OBJECTIVES

To determine (1) the general risk and outcome in the recovery room among 4 different anesthetic techniques associated with 2 different extracorporeal shock wave lithotripsy (ESWL) machines and (2) any gender-related differences among patients undergoing ESWL.

DESIGN

Retrospective statistical analysis.

SETTING

University medical center.

PATIENTS

2,203 ASA physical status I-IV patients undergoing ESWL over a 46-month period.

INTERVENTIONS

A review of the chart records of patients who received 1 of 4 anesthetic techniques (general, spinal, epidural, or monitored anesthesia care) on 1 of 2 ESWL machines.

MEASUREMENTS AND MAIN RESULTS

A positive finding was defined as a complication and/or side effect of such significance as to require a treatment order or recovery room note on the patient's chart. The main complications and/or side effects were nausea and/or vomiting, flank pain, and hypertension. Female patients experienced flank pain and nausea and/or vomiting with general anesthesia and monitored anesthesia care at approximately twice the frequency of males.

CONCLUSIONS

(1) Overall, ESWL is relatively safe. Both machine types and all anesthetic techniques exhibited a low risk and good outcome. (2) There appear to be gender-related differences during ESWL. Female and male patients may have different pain and nausea and/or vomiting thresholds during ESWL.

In situ extracorporeal shock wave lithotripsy for upper ureteral stones: experience with 65 patients

A total of 65 patients with 67 upper ureteral stones underwent in situ extracorporeal shock wave lithotripsy (ESWL) between March 1990 and September 1990. For stone disintegration the electrohydraulic shock wave lithotripter Tripter XI (Direx) was used. Eighty-seven per cent of stones showed satisfactory disintegration after the first treatment and a further 9 per cent after repeat treatments. The stone-free rate at 12 weeks was 85 per cent. General anaesthesia was needed in only 12 per cent of patients. The retreatment rate was 13 per cent. It was concluded that in situ ESWL is an effective procedure with negligible morbidity for treating upper ureteral stones.

An unusual complication of extracorporeal shock wave lithotripsy: urinoma due to rupture of the renal pelvis

A case of a female patient with urinoma due to rupture of the renal pelvis after extracorporeal shock wave lithotripsy is described. Although temporary perirenal fluid accumulations after extracorporeal shock wave lithotripsy have been reported previously, possibly this is the first case presenting with an abdominal mass due to retroperitoneal urine collection.

Complications of renal extracorporeal shock wave lithotripsy reviewed

Renal extracorporeal shock wave lithotripsy (ESWL) is a noninvasive and effective method for the treatment of a variety of urinary tract calculi with significantly lower morbidity than both surgical procedures for stone removal (pyelolithotomy/ureterolithotomy) and percutaneous nephrostolithotomy. Though significant, severe complications are rare, ESWL therapy can result in a wide spectrum of tissue injury. This article serves to review the currently known complications of ESWL, which radiologists may encounter, providing an understanding of the potential effects of shock waves on body organs and the resultant functional and morphologic changes that may result.

Acute changes of serum markers for tissue damage after ESWL of kidney stones

Seventeen serum markers (including 9 enzyme activities) for eventual tissue damage were studied after ESWL in 40 patients with unilateral kidney calculosis. No changes were established in the 8 non-enzymic parameters and the activities of amylase, lipase, AST (GOT), ALT (GPT) and CK-MB. A statistically significant increase was found in LDH, alpha-HBDH, CK (twice) and glutamate dehydrogenase (3 times). The slight elevation of LDH and alpha-HBDH could be due to haemolysis caused by the shock waves. Increased activity of CK suggested myolysis and that of GlDH a hepatocellular damage.