Kidney changes after extracorporeal shock wave lithotripsy: CT evaluation

Shear Wave Elastographic Alterations in the Kidney After Extracorporeal Shock Wave Lithotripsy

OBJECTIVES

Extracorporeal shock wave lithotripsy (ESWL) is a method used frequently for the treatment of renal stone disease. Although its safety is proven, there are still concerns about its unwanted effects on kidneys. In this prospective study, we aimed to evaluate renal tissue alterations with shear wave elastography (SWE) after ESWL. We also studied the correlation between SWE and resistive index (RI) changes.

METHODS

The study included 59 patients who underwent ESWL treatment for renal stone disease. We performed SWE and color Doppler ultrasonography to calculate SWE and RI values before, 1 hour after, and 1 week after lithotripsy treatment. A binary comparison was performed by the Bonferroni test. The correlation between SWE and RI values was evaluated by a Pearson correlation analysis.

RESULTS

The patients included 26 women (44.1%) and 33 men (55.9%). Their ages ranged from 20 to 65 years (mean ± SD, 45.0 ± 1.1 years). Stone diameters ranged from 7 to 19 mm (mean, 13.0 ± 0.5 mm). There was a significant difference in SWE values before and 1 hour after lithotripsy treatment (P = .001; P < .01). In the follow-up measurement 1 week after treatment, this difference disappeared (P > .99; P > .05). Resistive index values increased significantly 1 hour after lithotripsy treatment and returned to prelithotripsy values 1 week after treatment. In the correlation analysis, SWE and RI values were not correlated.

CONCLUSIONS

Measurements of alterations in SWE values after ESWL can provide useful information about renal tissue injury.

Current Trends in the Management of Urinary Stones

The treatment of renal and ureteral stones has undergone rapid and major changes over the past ten years. Extracorporeal Shockwave lithotripsy has become the most commonly used modality for the treatment of renal and upper ureteral stones. Lower ureteral stones are more commonly being approached by retrograde techniques. Percutaneous nephrolithotomy, medical therapy, and open surgical nephrolithotomy offer viable alternatives in given situations. Presented here is the current application of each of these techniques, both alone and in combination, for the treatment of urinary stones.

Diagnostic and prognostic role of computed tomography in extracorporeal shock wave lithotripsy complications

Purpose:

To evaluate the role of multidetector computed tomography (MDCT) in recognizing the complications of extracorporeal shock wave lithotripsy (ESWL) and providing a prognostic grading system for the therapeutic approach.

Materials and Methods:

A total of 43 patients who underwent ESWL because of urinary stone disease were assessed by 320-row MDCT examination before and after ESWL. Pre-ESWL CT unenhanced scans were performed for diagnosing stone disease. Post-ESWL CT scans were acquired before and after intravenous injection of contrast medium searching for peri-renal fluid collection or hyper-density, pyelic or ureteral wall thickening, blood clots in the urinary tract, peri- or intra-renal hematoma or abscess, active bleeding. A severity grading system of ESWL complications was established.

Results:

Patients were affected by renal (n = 36) or ureteral (n = 7) lithiasis. Post-ESWL CT examination detected small fluid collections and hyper-density of peri-renal fat tissue in 35/43 patients (81%), pyelic or ureteral wall thickening in 2/43 (4%), blood clots in the urinary tract in 9/43 (21%), renal abscesses or hematomas with a diameter of <2 cm in 10/43 (23%), large retroperitoneal collections in 3/43 (7%), active bleeding from renal vessels in 1/43 (2%). Mild complications were found in 30 cases; moderate in 9; severe in 4. The therapeutic choice was represented by clinical follow-up (n = 20), clinical and CT follow-up (n = 10), ureteral stenting (n = 9), drainage of large retroperitoneal collections (n = 3), and arterial embolization (n = 1).

Conclusion:

MDCT plays a crucial role in the diagnosis of urolithiasis and follow-up of patients treated with ESWL recognizing its complications and providing therapeutic and prognostic indications.

Does Stepwise Voltage Ramping Protect the Kidney from Injury During Extracorporeal Shockwave Lithotripsy? Results of a Prospective Randomized Trial

BACKGROUND

Renal damage is more frequent with new-generation lithotripters. However, animal studies suggest that voltage ramping minimizes the risk of complications following extracorporeal shock wave lithotripsy (SWL). In the clinical setting, the optimal voltage strategy remains unclear.

OBJECTIVE

To evaluate whether stepwise voltage ramping can protect the kidney from damage during SWL.

DESIGN, SETTING, AND PARTICIPANTS

A total of 418 patients with solitary or multiple unilateral kidney stones were randomized to receive SWL using a Modulith SLX-F2 lithotripter with either stepwise voltage ramping (n=213) or a fixed maximal voltage (n=205).

INTERVENTION

SWL.

OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was sonographic evidence of renal hematomas. Secondary outcomes included levels of urinary markers of renal damage, stone disintegration, stone-free rate, and rates of secondary interventions within 3 mo of SWL. Descriptive statistics were used to compare clinical outcomes between the two groups. A logistic regression model was generated to assess predictors of hematomas.

RESULTS AND LIMITATIONS

Significantly fewer hematomas occurred in the ramping group(12/213, 5.6%) than in the fixed group (27/205, 13%; p=0.008). There was some evidence that the fixed group had higher urinary β2-microglobulin levels after SWL compared to the ramping group (p=0.06). Urinary microalbumin levels, stone disintegration, stone-free rate, and rates of secondary interventions did not significantly differ between the groups. The logistic regression model showed a significantly higher risk of renal hematomas in older patients (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.00-1.05; p=0.04). Stepwise voltage ramping was associated with a lower risk of hematomas (OR 0.39, 95% CI 0.19-0.80; p=0.01). The study was limited by the use of ultrasound to detect hematomas.

CONCLUSIONS

In this prospective randomized study, stepwise voltage ramping during SWL was associated with a lower risk of renal damage compared to a fixed maximal voltage without compromising treatment effectiveness.

PATIENT SUMMARY

Lithotripsy is a noninvasive technique for urinary stone disintegration using ultrasonic energy. In this study, two voltage strategies are compared. The results show that a progressive increase in voltage during lithotripsy decreases the risk of renal hematomas while maintaining excellent outcomes.

TRIAL REGISTRATION

ISRCTN95762080.

A Rare Complication of Extracorporeal Shock Wave Lithotripsy: Intrarenal Hematoma Mimicking Pelvis Renalis Tumor

Extracorporeal shock wave lithotripsy (SWL) is a very commonly used treatment modality for appropriate sized stones. Even though it is a noninvasive treatment technique, major complications may occur following SWL sessions. Herein, we report a 17-year-old male patient, who received 2 sessions of SWL treatment for his left kidney stone, 4 months before his admission. Imaging methods showed an enhanced left renal pelvis mass with contrast-enhanced computerized tomography (CT) and this finding raised a suspicion of pelvis renalis tumor. Diagnostic ureterorenoscopy was planned for the patient and operation revealed a left intrarenal hematoma, which was drained percutaneously during the same operation. Careful history should be taken from patients with renal pelvis masses and intrarenal hematoma formation should be kept in mind, especially if the patient has a previous SWL history.

Goodpasture's disease following extracorporeal shock wave lithotripsy: a case report & literature review

Shock wave lithotripsy may unmask epitopes within the glomerular basement membrane, leading to the formation of anti-glomerular basement membrane (GBM) antibodies and clinical disease in susceptible individuals. Although rare, our case highlights the need for vigilant monitoring of renal function following extracorporeal shock wave lithotripsy. This may allow for early recognition, treatment and improved outcome of anti-GBM disease.

Renal stones in pregnancy

Diagnosis and treatment of renal stones during pregnancy is a complex problem. Risks to the fetus from ionising radiation and interventional procedures need to be balanced with optimising clinical care for the mother. Management of such patients requires a clear understanding of available options, with a multidisciplinary team approach. In this review, we discuss the role of different diagnostic tests including ultrasound, magnetic resonance urography, and computerized tomography. We also provide an update on recent developments in the treatment of renal stones during pregnancy. Expectant management remains first-line treatment. Where definitive treatment of the stone is required, new evidence suggests that ureteroscopic stone removal may be equally safe, and possibly better than traditional temporising procedures.

Shock wave lithotripsy in patients requiring anticoagulation or antiplatelet agents

Extracorporeal shockwave lithotripsy (SWL) remains the only truly minimally invasive procedure for the treatment of upper tract nephrolithiasis. Recently, there has been a recent rise in the patients on antiplatelet agents. Therefore, the aim of the present study is to review the literature available regarding SWL in these high-risk patients requiring anti-coagulation therapy. Alternative therapies to SWL are also presented.

Subcapsular hepatic hematoma with right hepatic vein thrombosis: a complication of shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is a well-established, safe and effective therapeutic modality for surgical treatment of urolithiasis. Hematoma is a rare complication of ESWL and, when it occurs, typically involves the kidney. We report the case of a 71-year-old woman who developed severe, persistent abdominal pain after ESWL for a 9-mm stone at the ureteropelvic junction. Post-treatment CT scan demonstrated a 13 x 6-cm subcapsular hepatic hematoma. A follow-up CT scan showed expansion of the hematoma and development of hepatic vein thrombosis. This finding, along with persistent abdominal pain and rising liver transaminases, led to surgical intervention. The patient's symptoms resolved and liver function returned to baseline following liver decompression.

An exceedingly rare cause of secondary hypertension: bilateral renal artery dissection possibly secondary to extracorporeal shock-wave lithotripsy (ESWL)

Extracorporeal shock-wave lithotripsy (ESWL) is an effective and relatively non-invasive treatment modality for ureteral or renal calculi. Although it has been accepted as a safe procedure, minor and major complications have been reported after ESWL. Spontaneous renal artery dissection (SRAD) is a rare and usually misdiagnosed condition because of non-specific presentation of the patients. Depending on the severity of the extent of the dissection non-operative or surgical treatment modalities could be performed. We represent a patient with complaints of bilateral flank pain, hematuria and hypertensive urgency who was diagnosed as having bilateral SRAD possibly secondary to ESWL and chronic hypertension.

Urine cytology to evaluate urinary urothelial damage of shock-wave lithotripsy

Our aim is to study the prospective trial where urine cytology was used to detect the acute urothelial mucosal damage in patients who undergo extracorporeal shock waves lithotripsy (SWL). The study included 48 consecutive patients (28 male, 20 female) with mean age of 49.02 years (range 18-66) who were treated with SWL due to renal stones (30 patients) or upper ureter stones (18 patients). The mean calculi diameter was 12.44 mm (range 5-20). Urinary cytologic examinations were done for all patients immediately before and after SWL therapy and 10 days latter. The average numbers of transitional cells, red blood cells and myocytes were counted under 40 × magnification. In overall patients the average numbers of transitional cells at the cytologic examinations done immediately before and after SWL therapy were 1.6 and 7.53 cell/field, respectively (p = 0.001). The increment in transitional cells at cytologic examination after SWL was significantly influenced only by number of shock waves applied (p = 0.003). No muscle cell was detected in all cytologic examinations. The cytologic examinations which were done after 10 days of SWL therapy showed recovery from all cytologic abnormalities. The acute increment in number of transitional cells after the SWL is not clinically important and it is a temporary change. Urothelial lesion is limited to mucosal layer and there is no evidence of damage to basal membrane or deeper muscle layer. SWL safety on urothelial and muscular layer was demonstrated. However, evaluation of larger series with use of other lithotripters is necessary before reaching any definitive conclusions.

Preventive effects of COX-2 inhibitor, celecoxib on renal tubular injury induced by shock wave lithotriptor

Our study was designed to investigate the protective effect of the COX-2 inhibitor, celecoxib, on renal tubules against shock wave lithotripsy (SWL). Sprague-Dawley rats were randomly divided into three groups: sham, control, and COX-2 groups. The control group was administrated normal saline. The COX-2 group was administered celecoxib (10 mg/kg). After administration for 1 week, the control and COX-2 groups received 1,000 shock waves. Before and after SWL, 24-h urine was collected. CCr was measured to assess renal function. To determine the renal tubular injury, N-acetyl glucosaminidase (NAG) and beta-2 microglobulin levels in urine were quantified. The COX-2 gene expression was compared between the three groups. Prior to SWL, all groups had similar levels of NAG and beta-2 microglobulin. After SWL, all groups showed similar CCr. Compared with the sham group, control and COX-2 groups produced increase of NAG and beta-2 microglobulin excretion. However, NAG and beta-2 microglobulin excretions were significantly lower in the COX-2 group than control group. The COX-2 gene expression did not increase in the sham group. However, the COX-2 gene expression was significantly increased in the control group, which was prevented by celecoxib in COX-2 group. Biochemical findings supported a renal protective effect of celecoxib on SWL. This study suggests that celecoxib would be useful prior and after SWL because of renal protective effects.

Kidney stones: painful and common--but preventable

Kidney stones are among the more common and painful urological disorders, affecting approximately 10% of Americans. While most stones pass spontaneously, obstructions result in renal colic, often requiring aggressive management of pain. If obstructions persist, extracorporeal shockwave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy may be required for a stone's removal. Recurrence rates are high, and prevention includes increased fluid intake, dietary restrictions, and the use of pharmacotherapy. Stone recurrence increases with age, underscoring the importance of prevention for those 60 years of age and older.

[The future of ESWL]

With the introduction of the Dornier HM3 lithotripter, the successful history of extracorporeal shock wave lithotripsy (ESWL) for noninvasive treatment of urinary stones began about 25 years ago. The development of newer lithotripters has not been able to improve clinical efficacy because the shock wave parameters specifically responsible for stone disintegration or tissue trauma and pain induction have not yet been identified. Actual research in lithotripter technology deals with modification of the focal point. The evolution of endoscopic procedures, ureterorenoscopy, and percutaneous nephrolithotomy took longer but was more successful in terms of clinical efficacy. Nowadays, ESWL or an endoscopic procedure is offered as a reasonable option for most urinary stone cases. Therefore, economic aspects and the surgeon's expertise will become greater factors when a procedure is chosen. ESWL, with or without anaesthesia, will be an inherent part of future treatment modalities for urinary stones.

A case of portal venous gas after extracorporeal shockwave lithotripsy and obstructive pyelonephritis

The presence of gas in the portal venous system is considered an ominous sign often mandating immediate exploratory laparotomy; however, there are numerous reports of benign incidences of this finding. This report describes a case of portal venous gas after extracorporeal shockwave lithotripsy. The patient had the rare complication of obstructive pyleonephritis that progressed to sepsis and subsequently underwent a negative exploratory laparotomy. It is suggested that the radiographic finding of portal venous gas should be correlated with the likely cause and overall clinical picture.

Is extracorporeal shock wave lithotripsy in pediatrics a safe procedure?

Removal of urinary calculi is an essential element in the successful treatment of patients with urinary stone disease. The new generation of lithotriptors allows the treatment without the need for general anesthesia. The patients, often outpatients, have a faster discharge from the hospital with a reduction of hospitalization time and operating costs. Shock wave lithotripsy (SWL) is currently considered a safe technique for treatment of pediatric urinary lithiasias, with a low percentage of complications and subsequent surgical retreatments. But can we define SWL as a safe procedure in pediatrics? Herein, we will review the literature to justify SWL safety in children, focusing on important parameters as the insertion of preoperative stenting, side effects, and complications after the procedure.

The acute and long-term adverse effects of shock wave lithotripsy

Shock wave lithotripsy (SWL) has proven to be a highly effective treatment for the removal of kidney stones. Shock waves (SWs) can be used to break most stone types, and because lithotripsy is the only noninvasive treatment for urinary stones, SWL is particularly attractive. On the downside SWL can cause vascular trauma to the kidney and surrounding organs. This acute SW damage can be severe, can lead to scarring with a permanent loss of functional renal volume, and has been linked to potentially serious long-term adverse effects. A recent retrospective study linking lithotripsy to the development of diabetes mellitus has further focused attention on the possibility that SWL may lead to life-altering chronic effects. Thus, it appears that what was once considered to be an entirely safe means to eliminate renal stones can elicit potentially severe unintended consequences. The purpose of this review is to put these findings in perspective. The goal is to explain the factors that influence the severity of SWL injury, update current understanding of the long-term consequences of SW damage, describe the physical mechanisms thought to cause SWL injury, and introduce treatment protocols to improve stone breakage and reduce tissue damage.

A systematic review of medical therapy to facilitate passage of ureteral calculi

STUDY OBJECTIVE

Acute renal colic is a common presenting complaint to the emergency department. Recently, medical expulsive therapy using alpha-antagonists or calcium channel blockers has been shown to augment stone passage rates of moderately sized, distal, ureteral stones. Herein is a systematic evaluation of the use of medical expulsive therapy to facilitate ureteral stone expulsion.

METHODS

We searched the databases of MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. Additional sources included key urologic journals and bibliographies of selected articles. We included studies that incorporated a randomized or controlled clinical trial design, patients older than 18 years, treatment in which an alpha-antagonist or calcium channel blocker was compared to a standard therapy group, and studies that reported stone expulsion rates. A random effects model was used to obtain summary risk ratios (RRs) and 95% confidence intervals (CIs) for stone expulsion rate.

RESULTS

A pooled analysis of 16 studies using an alpha-antagonist and 9 studies using a calcium channel blocker suggested that the addition of these agents compared to standard therapy significantly improved spontaneous stone expulsion (alpha-antagonist RR 1.59; 95% CI 1.44 to 1.75; number needed to treat 3.3 [95% CI 2.1 to 4.5]; calcium channel blocker RR 1.50; 95% CI 1.34 to 1.68; number needed to treat 3.9 [95% CI 3.2 to 4.6]) in patients with distal ureteral stones. Subgroup analysis of trials using concomitant medications (ie, low-dose steroids, antibiotics, and elimination of trials using an anticholinergic agent) yielded a similar improvement in stone expulsion rate. Adverse effects were noted in 4% of patients receiving alpha-antagonist and in 15.2% of patients receiving calcium channel blockers.

CONCLUSION

Our results suggest that "medical expulsive therapy," using either alpha-antagonists or calcium channel blockers, augments the stone expulsion rate compared to standard therapy for moderately sized distal ureteral stones.

Treatment Selection and Outcomes: Renal Calculi

This article summarizes the history of how renal stones have been treated over the centuries and reviews current treatments and outcomes for renal stones. The authors provide an algorithm based on available outcome data for shock wave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy.

Ureterstriktur nach extrakorporaler Stoßwellenlithotripsie

Extracorporeal shock wave lithotripsy (ESWL) is considered a very safe and noninvasive procedure for the treatment of urolithiasis. Achievements in the technical development of recent decades resulted in a continuous reduction of side effects. One of our patients, a woman with cystinuria, developed a temporary ureteral stricture after several sessions of ESWL. Encouraged by this observation we set out to explore--based on a MEDLINE literature search--published reports of more severe side effects observed in modern ESWL therapy. Besides hydronephrosis and renal colic the most common side effects were renal and perirenal hematomas in up to 4% in the larger series. Uncommon extrarenal complications are described mostly in case reports, which are also outlined in this report. The injury of visceral organs (liver, spleen, gut, pancreas) was published most frequently. A rupture or dissection of an abdominal aortic aneurysm as an outstanding serious complication was also reported several times. Taking obvious and well-known contraindications into consideration and carefully preparing the patients for the therapy (i.e., checking hemostasis, drug history), ESWL is a very safe procedure with a low risk of serious complications. Yet, postoperative clinical and ultrasound monitoring seems to be essential especially with respect to the increasing numbers of outpatient procedures.

Case report: scrotal ecchymosis after shockwave lithotripsy

Shockwave lithotripsy (SWL) is the treatment of choice for most renal calculi because it is highly effective and relatively noninvasive. Although complications of SWL are relatively few, one that occurs more frequently is perirenal hematoma, usually diagnosed by radiologic procedures. We present an interesting case of scrotal ecchymosis as an unusual presentation of perirenal hematoma causing ipsilateral spermatic-vein thrombosis after SWL for a left renal stone. To our knowledge, this condition has not been reported previously.

Medical therapy to facilitate urinary stone passage: a meta-analysis

BACKGROUND

Medical therapies to ease urinary-stone passage have been reported, but are not generally used. If effective, such therapies would increase the options for treatment of urinary stones. To assess efficacy, we sought to identify and summarise all randomised controlled trials in which calcium-channel blockers or alpha blockers were used to treat urinary stone disease.

METHODS

We searched MEDLINE, Pre-MEDLINE, CINAHL, and EMBASE, as well as scientific meeting abstracts, up to July, 2005. All randomised controlled trials in which calcium-channel blockers or alpha blockers were used to treat ureteral stones were eligible for inclusion in our analysis. Data from nine trials (number of patients=693) were pooled. The main outcome was the proportion of patients who passed stones. We calculated the summary estimate of effect associated with medical therapy use using random-effects and fixed-effects models.

FINDINGS

Patients given calcium-channel blockers or alpha blockers had a 65% (absolute risk reduction=0.31 95% CI 0.25-0.38) greater likelihood of stone passage than those not given such treatment (pooled risk ratio 1.65; 95% CI 1.45-1.88). The pooled risk ratio for alpha blockers was 1.54 (1.29-1.85) and for calcium-channel blockers with steroids was 1.90 (1.51-2.40). The proportion of heterogeneity not explained by chance alone was 28%. The number needed to treat was 4.

INTERPRETATION

Although a high-quality randomised trial is necessary to confirm its efficacy, our findings suggest that medical therapy is an option for facilitation of urinary-stone passage for patients amenable to conservative management, potentially obviating the need for surgery.

A novel antioxidant agent, astragalosides, prevents shock wave-induced renal oxidative injury in rabbits

Extracorporeal shock-wave lithotripsy (ESWL)-induced renal damage can occur as a result of multiple mechanisms, including small vessel injury and free radical formation. Our previous studies have demonstrated that Astragalus membranaceus (AM), a traditional Chinese herb, could significantly alleviate shock wave-induced renal oxidative injury, and its renoprotective effects were superior to those of varapamil, a calcium antagonist, which were considered to be a powerful agent in treating renal damage during ESWL. However, the effective antioxidant ingredient of this herb in the setting of lithotripsy remains unclear. Astragalosides, the major components of AM, was demonstrated to have superior antioxidation properties both in vitro and in vivo. Therefore, in this study we further investigate the potential effects of astragalosides on the shock wave-induced oxidative stress in rabbit kidney. Thirty male rabbits were randomly assigned to two groups, each consisting of 15 rabbits: (1) control group, (2) astragaloside-treated group. Each group of animals underwent 1,500 shock waves to the right kidney. Peripheral blood, urine and kidney tissue samples were collected pre- and post-ESWL. The level of urinary N-acetyl-beta-glucosaminidase (NAG), serum creatinine, serum or homogenates malondialdehyde (MDA) and superoxide dismutase (SOD), respectively, were detected. Histological alterations were also examined through light microcopy and transmission electron microscopy. In the control group, shock wave significantly increased the level of MDA and decreased SOD activity in both blood and renal homogenates (P<0.05, respectively). The comparison between the control and astragalosides group demonstrated that astragalosides could significantly decrease the level of MDA (P<0.05) and inhibit the decline of SOD activity (P<0.05). After exposure to shock waves, the activity of urinary NAG increased significantly in the control group (P<0.05). However, the concentration of serum creatinine did not change significantly. The comparison between the control and astragalosides group demonstrated that astragalosides significantly reduced the shock wave-induced leakage of NAG into the urine (P<0.05). Histological examination also showed that renal morphological impairments were much milder in astragaloside-treated rabbits than those of the control group. Our results indicated that astragaloside treatment provided significant protection against shock wave-induced renal oxidative injury.

Minimally invasive management of urolithiasis

The management of urolithiasis has radically changed over the last two decades. Open surgery has been almost completely replaced by minimally invasive procedures, mainly extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy (URS). Although these treatment modalities have been proven to be very safe and effective, serious complications can occur. Prompt diagnosis is often essential and may even be lifesaving. Radiologists play an important role in this setting, since many of these complications can be readily diagnosed by imaging. Awareness of the wide spectrum of complications may be crucial in interpreting imaging studies of patients who have undergone one of these procedures. This article reviews the contemporary management of ureteric stones with ESWL and URS and illustrates the radiological findings of complications of these procedures.

The isolated perfused kidney: an in vitro test system for evaluation of renal tissue damage induced by high-energy shockwaves sources

Most of our knowledge of shockwave-induced renal damage is based on animal experiments and clinical observation. We developed a tissue model using isolated porcine kidneys perfused with Berliner Blau dye in physiologic saline using a Ureteromat Perez-Castro peristaltic pump connected to the renal artery. Reproducible results were obtained under a variety of experimental conditions. Further refinements of the model might consist of interposition of tissue layers in the shockwave path or simulation of ventilatory movements.

A MULTIVARIATE ANALYSIS OF RISK FACTORS ASSOCIATED WITH SUBCAPSULAR HEMATOMA FORMATION FOLLOWING ELECTROMAGNETIC SHOCK WAVE LITHOTRIPSY

PURPOSE

Subcapsular or perinephric hematoma is one of the most frequent and potentially serious complications of extracorporeal shock wave lithotripsy (SWL). We determined the incidence of and risk factors for renal hematomas following electromagnetic shock wave lithotripsy.

MATERIALS AND METHODS

Between February 1999 and August 2003, 570 SWL treatments were performed using a Modulith SLX electromagnetic lithotriptor (Storz, St. Louis, Missouri). A total of 415 of these treatments in 317 patients were performed for stones in the renal pelvis or calices and these treatment episodes represent the study group reported. Treatment episodes were reviewed from a prospective institutional review board approved registry and analyzed for patient age, gender, body mass index, mean arterial pressure at induction, stone location, total number of shock waves and peak shock wave intensity.

RESULTS

Following these 415 episodes subcapsular or perinephric hematomas developed in 17 patients for an overall incidence of 4.1%. The probability of hematoma after shock wave lithotripsy increased significantly as patient age at treatment increased, such that the probability of hematoma was estimated to be 1.67 times greater for each 10-year incremental increase in patient age. None of the other variables analyzed were significantly related to the incidence of hematoma formation at the 0.05 level.

CONCLUSIONS

The incidence of renal hematoma formation following electromagnetic SWL for renal calculus was 4.1%. The probability of hematoma increased significantly with increasing patient age but it was not associated with increasing mean arterial pressure at treatment. These findings are in contrast to previous reports of hematoma associated with electrohydraulic SWL. These differences may be a consequence of the smaller focal zone and higher peak pressure associated with Storz Modulith electromagnetic SWL and, just as importantly, a consequence of the difference in the manner in which blood pressure was defined.

Effects of extracorporeal shock-wave lithotripsy on intrarenal resistive index

OBJECTIVE

This prospective study was performed to determine whether extracorporeal shock-wave lithotripsy (ESWL), widely used for treating renal and ureteral stones, affects the kidney interlobar artery resistive index (RI).

MATERIAL AND METHODS

A total of 43 patients (30 with renal and 13 with ureteral stones) underwent color Doppler examination before and 30 min and 3 h after ESWL. Seventeen patients with renal and nine with ureteral stones underwent Doppler examination 2 weeks later. Measurements were made near the stones (nearby region), at least 2 cm from the stones (remote region) and in the contralateral kidney for renal stones, and in the ipsilateral and contralateral kidneys for ureteral stones.

RESULTS

In patients with renal stones, the RI was increased 30 min and 3 h after ESWL in the nearby and remote regions, and more markedly in the former. In the contralateral kidney, there was an increase in RI only at 3 h, which was less than that in the ipsilateral kidney. The RI at 2 weeks post-ESWL in the nearby region and contralateral kidney did not differ from the pre-ESWL values. ESWL performed for ureteral stones caused no increase in RI in the ipsilateral kidney.

CONCLUSION

Patients with renal stones had a temporary increase in RI in the hours following ESWL in both the ipsilateral and contralateral kidneys, which was highest in the region near the stones and lowest in the contralateral kidney. Two weeks later, the RI in both areas had returned to pre-ESWL levels.

Evaluation of a Bifocal Reflector on a Clinical Lithotripter

PURPOSE

To perform in vitro and in vivo tests using a clinical lithotripter in order to determine whether a bifocal reflector is more efficient and produces the same or less tissue damage than a conventional ellipsoidal reflector for electrohydraulic lithotripters.

MATERIALS AND METHODS

A standard ellipsoidal and a novel bifocal reflector were tested on a Tripter Compact lithotripter (Direx Medical Systems, Petach Tikva, Israel). The bifocal reflector was constructed by joining two sectors of two rotationally symmetrical ellipsoidal reflectors having different distances between their foci. The F1 foci of the sectors coincided, creating a separation between the F2 foci. The fragmentation efficiency of the reflectors was compared using kidney-stone models. Shockwave-induced trauma was evaluated in vivo by treating both kidneys of six healthy dogs. One kidney was exposed to shockwaves generated with the conventional reflector, and the other kidney was treated using the bifocal reflector. Pressure measurements were obtained for both reflectors using needle hydrophones.

RESULTS

The new design appeared to be more efficient than the conventional reflector in breaking up kidney-stone models. Tissue damage did not increase when using the bifocal reflector.

CONCLUSION

The use of bifocal, instead of standard ellipsoidal, reflectors should be considered as an alternative to improve extracorporeal shockwave lithotripsy.

Artificial neural networks in predicting optimum renal stone fragmentation by extracorporeal shock wave lithotripsy: a preliminary study

OBJECTIVE

To assess the ability of artificial neural networks (ANNs) to predict optimum renal stone fragmentation in patients being managed by extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND METHODS

The study included 82 patients with renal stones who were being treated by ESWL. Data (input and output values) from 60 patients in whom there was optimum fragmentation of stones by ESWL were used for training the ANN. These data mainly included the 24-h urinary variables, the radiological features of the stone disease and the ESWL settings used. The predictability of the trained ANN was tested on 22 subsequent patients, by supplying the input variables of the 22 patients into the trained ANN and recording the output values (predicted values). After subjecting these patients to ESWL, the actual results (observed values) were recorded. The predicted and the observed values were then compared.

RESULTS

In the 22 patients in whom predictability was tested, the trained ANN predicted optimum fragmentation at < or = 13 000 shocks/stone (as per study protocol) in 17 and optimum fragmentation at> 13 000 shocks/stone in the other five. In the 17 patients (test set) where the trained ANN had predicted optimum fragmentation at < or = 13 000 shocks/stone, the optimum fragmentation was at that value, although the predicted and observed values were not identical. The overall correlation between the predicted and the observed values was 75.5% (correlation coefficient 0.7547) in these 17 patients. Of the other five patients, none had optimum fragmentation at < 13 000 shocks/stone, as predicted by the trained ANN, giving complete accuracy for this factor.

CONCLUSION

This was a pilot study, i.e. an initial attempt to use an ANN in this regard, and although there were few patients, such that it is not possible to make final recommendations, the overall predictability was approximately 75%. An encouraging outcome of the study was that the trained ANN identified patients unlikely to benefit from ESWL. Using a larger dataset and identifying more significant variables, while eliminating inputs with a negative effect, the efficiency and utility of this ANN can probably be enhanced and in future it might be possible to predict stone fragmentation with reasonable accuracy.

Urinary tract stones--Part II: current status of treatment

The majority of renal and ureteric stones are now managed by minimally invasive techniques, for example nephrostomy, ureteral stents, extracorporeal shockwave lithotripsy or percutaneous nephrolithotomy. A multi-disciplinary approach is necessary, and this review examines the status of modern stone therapy and the contribution of the radiology department.

Long-term results after percutaneous minimally invasive procedure treatment of symptomatic simple renal cysts

OBJECTIVE

To assess the effectiveness and long-term results of two repeated ethanol injections in the treatment of symptomatic renal cysts.

METHODS

Sixty-eight patients 47 to 75 years old with 77 large (6.3-14.8 cm; mean 8.62 cm) symptomatic cysts were included in this study. Of the 68 patients, in 4 cases there were renal cysts associated with renal calculi. An 8FR Pigtail catheter was inserted into the cyst under ultrasound guidance followed by aspiration of cystic fluid. Two repeated ethanol 95% injections were performed every 24 hours. Patients were followed-up by ultrasonography for a period of 12-48 months (mean 30).

RESULTS

In two patients the cyst puncture was not feasible because of poor visualization of puncture site while in one patient there was communication of cystic cavity with the pelvocaliceal system. In these patients surgical resection of cysts was performed. Complete and partial regression rates were 57/68 (83.82%) and 8/68 (11.76%) respectively. In four patients with renal stones and renal cysts, extracorporeal shock wave lithotripsy (ESWL) was successfully executed I month after sclerotherapy.

CONCLUSION

Our results suggest that percutaneous aspiration followed by two repeated ethanol injections is highly effective on reducing recurrence of simple renal cysts.

[Symptomatic subcapsular hepatic hematoma after renal extracorporeal shock wave lithotripsy]

The presentation of a hepatic subcapsular hematoma as a complication following the carrying out of an extracorporeal renal shock wave lithotripsy is fairly uncommon. We would like to describe the case of a patient who showed after extracorporeal renal post-lithotripsy intense abdominal symptoms and in which the presence of any prior hepatic pathology was ruled out, alterations in the blood coagulation system as well as anomalies in the execution of the extracorporeal lithotripsy as etiological mechanisms. We carried out a bibliographical review due to the rarity of the process described.

Extracorporeal shockwave lithotripsy in patients treated with antithrombotic agents

PATIENTS AND METHODS

Between January 1996 and December 1999, 749 patients underwent electromagnetic SWL. Among them, 23 patients, 19 with renal and 4 with ureteral stones, were receiving antithrombotic drugs (aspirin, ticlopidine, dipyridamole). According to the cardiologist and hematologist, we divided these patients into two groups: Group 1 had a low thromboembolic risk (previous myocardial infarction), and Group 2 had a high thromboembolic risk (aortocoronary bypass, atrial fibrillation, cerebrovascular disease, peripheral occlusive arterial disease). Group 1 patients discontinued their antiplatelet therapy 8 days prior to SWL to permit a sufficient number of functioning platelets to remain. Group 2 patients suspended antiplatelet therapy, and unfractioned heparin 5000 IU tid (8 a.m., 4 p.m., and 12 p.m.) was administered for the 8 days prior to SWL. On the ninth day of withdrawal, SWL was performed in all patients. Close follow-up was performed during the postoperative period (hemoglobin, hematocrit, kidney ultrasonography, plain abdominal film). The antithrombotic therapy was restored in all patients within 10 to 14 days of withdrawal.

RESULTS

Hematomas and thromboembolic events were not observed. At 3 months' follow-up, 14 patients (61%) were stone free, 3 (13%) had <4-mm fragments, and 6 (26%) had >4-mm residual fragments.

CONCLUSION

Our schedules for the suspension or substitution of antithrombotic therapy, although tested in a small number of patients, allowed us to perform SWL without hemorrhagic or thromboembolic complications.

Magnetic resonance imaging in endourology

Historically, the utilization of magnetic resonance imaging (MRI) in endourology has been limited. The availability of faster and stronger gradient systems has given rise to a number of data acquisition strategies that have significantly broadened the scope of MRI applications. These methods have led to the evaluation of anatomy and function using a single modality, and we describe our experience with MRI for comprehensive evaluation of the obstructed ureteropelvic junction. We also utilize these new imaging sequences in the investigation of alterated renal hemodynamics after extracorporeal shockwave lithotripsy and present our preliminary data on the application of MR perfusion imaging as a noninvasive technique for the evaluation of renal blood flow.

Early observations of the effect of extracorporeal shockwave lithotripsy on blood pressure: a prospective randomized control clinical trial

OBJECTIVE

To determine, in a randomized controlled clinical trial, the effect of extracorporeal shock wave lithotripsy (ESWL) on blood pressure.

PATIENTS AND METHODS

The trial included 228 patients with small (< 15 mm) asymptomatic calyceal stones who were randomised to undergo ESWL (113 patients) or to an untreated (observed) control group (115 patients). Blood pressure was recorded at randomization using a standardized protocol. Patients undergoing ESWL received a mean (SD) of 5281 (3462) shocks over a mean of 1.75 sessions on one of two lithotripters. Patients were then followed annually, assessing blood pressure and changes in medication. Data were analysed on an intention-to-treat basis.

RESULTS

At randomization, 43% of patients in the control group and 53% in the ESWL group were hypertensive. Of the 228 randomized, 200 patients completed at least one annual follow-up, of whom 192 (93 in the control and 99 in the ESWL group) had their blood pressure recorded. The mean follow-up was 2.2 years; 35 (37%) patients in the control and 46 (46%) in the ESWL group were hypertensive (P = 0.19). Seven (7%) patients in the control group and 11 (11%) in the ESWL group were newly diagnosed to be hypertensive (P = 0.35).

CONCLUSIONS

In this randomized controlled clinical trial there was no evidence that ESWL causes changes in blood pressure.

Protective effect of aminophylline on renal perfusion changes induced by high-energy shockwaves identified by Gd-DTPA-enhanced first-pass perfusion MRI

PURPOSE

The purpose of this study was to evaluate regional renal hemodynamics in a noninvasive manner using gadolinium-DPTA magnetic resonance imaging (MRI) before and after extracorporeal shockwave lithotripsy (SWL). In addition, the renoprotective effect of intravenous aminophylline was evaluated on the perfusion on kidneys undergoing SWL.

PATIENTS AND METHODS

Ten randomly selected patients were evaluated for regional renal blood flow in the cortex and medulla with Gd-DTPA MRI studies within 2 weeks before and 4 hours after SWL. Five of these patients were treated with 500 mg of intravenous aminophylline 45 minutes prior to SWL. Renal hemodynamics were assessed utilizing relative perfusion indices (PI) calculated from signal intensity-v-time curves obtained from regions of interest (ROI). The ROI choice was based on the contrast-enhanced MRI images. Relative PIs of pre-SWL and post-SWL studies were compared in the first group of patients. Relative PIs of the treated kidney were compared with those of the contralateral kidney in the second group of patients, who received aminophylline.

RESULTS

In the group not treated with aminophylline, there was no significant difference in cortical perfusion before SWL (average PI -7+/-3%). However, after lithotripsy, there was a reduction of cortical flow (average PI 31+/-12%) in the treated kidney. In the group treated with aminophylline, renal hemodynamics study after SWL revealed no significant difference in relative perfusion (average PI -8+/-6%). Relative PIs of the medulla were small for all patients, but standard errors were large, indicating a wide range of values.

CONCLUSIONS

This study helps to establish reduced cortical flow after SWL and demonstrates that aminophylline attenuated this response in the kidneys subjected to lithotripsy. It appears that aminophylline administration causes no alteration in medullary blood flow.