Optimizing Shock Wave Lithotripsy in the 21st Century

Revealing physical interactions of ultrasound waves with the body through photoelasticity imaging

Ultrasound is a ubiquitous technology in medicine for screening, diagnosis, and treatment of disease. The functionality and efficacy of different ultrasound modes relies strongly on our understanding of the physical interactions between ultrasound waves and biological tissue structures. This article reviews the use of photoelasticity imaging for investigating ultrasound fields and interactions. Physical interactions are described for different ultrasound technologies, including those using linear and nonlinear ultrasound waves, as well as shock waves. The use of optical modulation of light by ultrasound is presented for shadowgraphic and photoelastic techniques. Investigations into shock wave and burst wave lithotripsy using photoelastic methods are summarized, along with other endoscopic forms of lithotripsy. Photoelasticity in soft tissue surrogate materials is reviewed, and its deployment in investigating tissue-bubble interactions, generated ultrasound waves, and traumatic brain injury, are discussed. With the continued growth of medical ultrasound, photoelasticity imaging can play a role in elucidating the physical mechanisms leading to useful bioeffects of ultrasound for imaging and therapy.

A prospective randomized controlled trial to determine the safety and efficacy of extracorporeal shock waves therapy for primary prevention of subclinical cardiotoxicity in breast cancer patients without a cardiovascular risk treated with doxorubicin

Background

Doxorubicin is a highly effective anti-cancer drug that causes left ventricular (LV) dysfunction and induces late-onset cardiomyopathy. However, an effective and clinically applicable preventive treatment is yet to be discovered.

Objective

Cardiac-Extracorporeal shockwave therapy (C-ESWT) has been suggested to treat inflammatory and ischemic diseases and protect cardiomyocytes from doxorubicin-induced cardiomyopathy. This study aims to assess the safety and efficacy of C-ESWT in the prevention of subclinical cardiotoxicity.

Methods

We enrolled 64 breast cancer patients. C-ESWT group 33 patients were treated with our C-ESWT (200 shots/spot at 0.09 mJ/mm2 for 20 spots, 3 times every six weeks). The efficacy endpoints were the difference in left ventricular global longitudinal strain (LVGLS) change by 2D speckle tracking echocardiography and chemotherapy-related cardiac dysfunction (CTRCD). Echocardiography was performed on the baseline line and every 4 cycles of chemotherapy, followed by a follow-up 3,6 months after chemotherapy to compare the incidence of cardiomyopathy of subclinical LV dysfunction due to chemotherapy between the two groups.

Results

Participants averaged 50 ± 9 years in age, 100% female. In the results of follow-up 6 months after the end of chemotherapy, there was a significant difference in delta LVGLS between the C-ESWT group and the control group (LVGLS; -1.1 ± 10.9% vs. -11.5 ± 11.6% p-value; <0.001). A total of 23% (15 patients) of patients developed CTRCD (Control group; 13 vs. C-ESWT group; (2). C-ESWT was performed safely without any serious adverse events.

Conclusion

In this prospective study, C-ESWT established efficacy in preventing subclinical cardiotoxicity, especially in breast cancer patients using doxorubicin chemotherapy, and the safety of C-ESWT.

Clinical Trial Registration

ClinicalTrials.gov, identifier (NCT05584163).

Analysis and prediction of postoperative recurrence of unilateral upper ureteral calculi in 243 cases (nomogram)

Objective: This study aimed to identify the risk factors for postoperative recurrence of unilateral upper ureteral calculi and develop a predictive nomogram. Patients and Methods: A retrospective analysis was conducted on 243 patients diagnosed with unilateral upper ureteral calculi who were treated at our hospital between January 1, 2016 and December 31, 2018. Patients were divided into two groups: recurrence or non-recurrence cohort. Differences in age, gender, smoking and/or drinking habit, laterality, stone diameter, ureteral stricture, stone incarceration, urinary tract infection, surgical intervention, operation time, body mass index, and metabolic syndrome were analyzed. Discrete risk factors were screened, and a nomogram was developed to predict the probability of stone recurrence. Results: The study found that the recurrence of ureteral calculi was associated with factors including stone diameter, ureteral stricture, stone incarceration, surgical intervention, operation time, metabolic syndrome, body mass index, triglycerides, diabetes, and high blood pressure (p < 0.05). Ureteral stricture, surgical intervention, metabolic syndrome, and triglycerides were found to be discrete risk factors for stone recurrence (p < 0.05). In addition, the study revealed that the stone recurrence rate of metabolic syndrome patients was significantly elevated (p < 0.05), as demonstrated by the survival curve. Lastly, using the nomogram, with an area under the curve value of 0.929, the recurrence rate of ureteral calculi was predicted. Conclusions: The study identified that preoperative ureteral stricture, laparoscopic ureterolithotomy, metabolic syndrome, and triglycerides are closely related to postoperative recurrence of ureteral calculi. The nomogram developed in this study can be used as a predictive tool for the recurrence rate of ureteral calculi.

Extracorporeal Shockwave Therapy in the Management of Sports Medicine Injuries

ABSTRACT

Treatment of musculoskeletal conditions in athletes with extracorporeal shockwave therapy (ESWT) is gaining popularity as greater evidence supports its use. ESWT protocols (describing energy flux density, number of impulses, type of shockwave (focused or radial), number/frequency/duration of treatment session, area of application, and postprocedural therapy protocols) can be adjusted in the clinical setting. Protocols vary across studies, and optimal protocols for most indications are yet to be determined. ESWT can safely be used to treat various musculoskeletal conditions in athletes, including rotator cuff tendinopathy, lateral elbow epicondlyopathy, greater trochanteric pain syndrome, hamstring tendinopathy, patellar tendinopathy, Achilles tendinopathy, other tendinopathies, plantar fasciopathy, bone stress injuries, and medial tibial stress syndrome. ESWT can be used to treat in-season athletes, as it often requires no/minimal time away from sport and may result in rapid benefits. ESWT should be used in conjunction with physical therapy to facilitate longer-term gains in function and to optimize healing.

The Outcomes of Extracorporeal Shock Wave Lithotripsy for High-Density Renal Stone on Non-Contrast Computed Tomography

Introduction Urinary lithiasis is usually managed by extracorporeal shock wave lithotripsy (ESWL). Patients are examined using non-contrast computed tomography (NCCT) in order to evaluate the feasibility of ESWL, according to where the stone is located and how big is its size. The objective of this study is to determine the outcomes of ESWL in patients having high-density renal stone, evaluated using NCCT. Materials and methods A descriptive case series study was conducted in the Department of Urology, Sindh Institute of Urology & Transplantation, Karachi for six months. Patients of either gender aged between 25-50 years, who presented with solitary renal and ureteric calculi of 0.5-2 cm in diameter and high-density renal stones [>750 hounsfield units (HU)] were enrolled. ESWL was performed and a satisfactory outcome was defined as complete stone clearance in less than or equal to three ESWL sessions. Statistical Package for Social Sciences (SPSS) (IBM Corp., Armonk, NY) was used to analyze frequencies and percentages of the number of ESWL sessions, complete renal stone clearances, and satisfactory outcomes at the end of 12 weeks. A p-value of <0.05 was considered significant. Results The mean age of the patient was reported to be 34.08 ± 9.53 years. 51.6% male preponderance was noticed. Renal and ureteric stones were found in 69.7% and 30.3% of patients, respectively. 21.3% of patients showed stone clearance after two ESWL sessions, 27% of patients after three ESWL sessions, and 51.6% of patients after four ESWL sessions. Stone clearance was found in 58.2% of patients and a satisfactory outcome was found in 42.6% of patients. Conclusions Our results signify a satisfactory outcome of extracorporeal shock wave lithotripsy for high-density renal stone on non-contrast computed tomography. Further studies on a larger scale are needed to validate these results.

Extracorporeal shock waves protect cardiomyocytes from doxorubicin-induced cardiomyopathy by upregulating survivin via the integrin-ILK-Akt-Sp1/p53 axis

Doxorubicin (DOX) is a widely used anti-cancer drug; however, it has limited application due to cardiotoxicity. Extracorporeal shock waves (ESW) have been suggested to treat inflammatory and ischemic diseases, but the concrete effect of ESW in DOX-induced cardiomyopathy remain obscure. After H9c2 cells were subjected to ESW (0.04 mJ/cm²), they were treated with 1 μM DOX. As a result, ESW protected cardiomyocytes from DOX-induced cell death. H9c2 cells treated with DOX downregulated p-Akt and survivin expression, whereas the ESW treatment recovered both, suggesting its anti-apoptotic effect. ESW activated integrin α_vβ₃ and α_vβ₅, cardiomyocyte mechanosensors, followed by upregulation of ILK, p-Akt and survivin levels. Further, Sp1 and p53 were determined as key transcriptional factors mediating survivin expression via Akt phosphorylation by ESW. In in vivo acute DOX-induced cardiomyopathy model, the echocardiographic results showed that group subjected to ESW recovered from acute DOX-induced cardiomyopathy; left ventricular function was improved. The immunohistochemical staining results showed increased survivin and Bcl2 expression in ESW + DOX group compared to those in the DOX-injected group. In conclusion, non-invasive shockwaves protect cardiomyocytes from DOX-induced cardiomyopathy by upregulating survivin via integrin-ILK-Akt-Sp1/p53 pathway. In vivo study proposed ESW as a new kind of specific and safe therapy against acute DOX-induced cardiomyopathy.

Effect of Shockwave Treatment for Management of Upper and Lower Extremity Musculoskeletal Conditions: A Narrative Review

Extracorporeal shockwave therapy (ESWT) is a technology that was first introduced into clinical practice in 1982 for urologic conditions. Subsequent clinical applications in musculoskeletal conditions have been described in treatment of plantar fasciopathy, both upper and lower extremity tendinopathies, greater trochanteric pain syndrome, medial tibial stress syndrome, management of nonunion fractures, and joint disease including avascular necrosis. The aim of this review is to summarize the current understanding of treatment of musculoskeletal conditions with ESWT, accounting for differences in treatment protocol and energy levels. Complications from ESWT are rare but include 2 reported cases of injury to bone and Achilles tendon rupture in older adults using focused shockwave. Collectively, studies suggest ESWT is generally well-tolerated treatment strategy for multiple musculoskeletal conditions commonly seen in clinical practice. LEVEL OF EVIDENCE: III.

Emergency extracorporeal shockwave lithotripsy as opposed to delayed shockwave lithotripsy for the treatment of acute renal colic due to obstructive ureteral stone: a prospective randomized trial

BACKGROUND

The aim of this study was to assess the efficacy of emergency extracorporeal shockwave lithotripsy (eSWL) as first-line treatment in patients with acute colic due to obstructive ureteral stone.

METHODS

Seventy-four patients were randomized to emergency SWL within 12 hours (eSWL group) and deferred SWL later than 3 days (dSWL group). Follow-up included ultrasound, KUB (kidney-ureter-bladder) radiography and CT (computed tomography) scan at 24 hours, 7 days, 1 and 3 months from the treatment. When necessary, repeated SWL (re-SWL) or ureteroscopy (auxiliary-URS) was performed. Preoperative and postoperative data were compared and stone free rates (SFR) and efficiency quotients (EQ) were evaluated. Analyses were performed using SAS software.

RESULTS

Complete data of 70 patients were collected. 36 underwent eSWL and 34 dSWL. The mean patient age was 48.7. Mean stone size was 9.8 mm (CI 95%: 8.9-10.8). 25 (35.7%) were proximal and 45 (64.3%) distal. Mean SWL energy was 19.2 kV (CI 95%: 18.5-19.9) and mean number of shocks was 2657 (CI 95%: 2513-2802). eSWL patients needs less auxiliary-URS than dSWL patients (13.9% vs. 44.1%, P=0.039) and less re-SWL sessions (8.3% vs. 32.4%, P=0.093). SFR at 24 hours was 52.8% and 11.8% (P<0.001) and the EQ at 3 months was 79.1% and 57.5% in the eSWL and dSWL group respectively. Patients from the dSWL group spent more time in the hospital (2.21 vs. 1.36 days, P=0.046) and complication rates between the two groups were similar.

CONCLUSIONS

eSWL is a safe procedure and delivers high SFR even within 24 hours especially for <10 mm stones. It is able to reduce the number of auxiliary procedures and hospitalization.

Has the pelvic renal stone position inside the upper loop of JJ stent any influence on the extracorporeal shock wave lithotripsy results?

Background

JJ stents are often encountered in patients with pelvic renal stones referred for shock wave lithotripsy, most of them being placed either for obstructive renal pelvic stones or for ureteric stones mobilized retrograde during the JJ stent insertion. The aim of the study was to determine whether the relative stone position in the upper loop of the JJ stent during extracorporeal shock wave lithotripsy (SWL) influences the efficiency of the procedure. The study was designed as a prospective cohort study on 162 patients addressing the same urological department, with single renal pelvic stone (primary or mobilized to the renal pelvis during the insertion of JJ stent), smaller than 15 mm, with JJ stent, treated by SWL using a second generation spark gap lithotripter, 18 kV, 3000 waves/session. Patients were divided in three groups according to the relative position of the stone to the upper loop of the JJ stent as appears on plain X-ray: stone-inside-loop, loop-crossing-stone and stone-outside the loop. The SWL success rate was the primary outcome of the study. p Value, Chi square and Kruskal–Wallis tests were used for statistical analysis.

Results

For stone-inside-loop cases, SWL efficiency was 22.7 versus 42 % for all the other cases (p = 0.002). Other factors for decreased SWL success rate were: higher stone radio-opacity, larger JJ of stent and obese patients. Study limitation is represented by the relative small study group and by the evaluation of stone density using plain X-ray instead of computer tomography.

Conclusions

For pelvic renal stones having the same density characteristics studied by plain X-ray, the SWL efficiency is lower in stone-inside-loop cases comparing with the other positions. The overall stone free rate for renal pelvic stones could be explained by the second generation lithotripter used for all procedures.

In Vitro Assessment of Three Clinical Lithotripters Employing Different Shock Wave Generators

OBJECTIVE

To test the hypothesis that shock wave lithotripsy machines vary in their ability to fragment standardized artificial urinary calculi.

MATERIALS AND METHODS

An in vitro test configuration was used to fragment synthetic U-30 Gypsum (U.S. Gypsum, Chicago, IL) stones (mean length 7.1 ± 0.2 mm, mean diameter 6.5 ± 0.07 mm, mean mass 299 ± 16 mg) using the Sonolith i-sys (EDAP TMS, Vaulx-en-Velin, France), Modulith SLX F2 (Storz Medical AG, Tägerwilen, Switzerland), and Piezolith 3000 (Richard Wolf GmbH, Knittlingen, Germany) lithotripters. Gypsum stones were placed at the nominal focus and treated with 250, 500, or 1000 shocks. The residual mass following passage through a 2-mm wire mesh was measured and compared using ANOVA and the Tukey-Kramer HSD test.

RESULTS

There was no statistically significant difference between the Modulith SLX F2 and Piezolith 3000 lithotripters for 250 and 1000 shock treatments (p = 0.34 and 0.31, respectively). The Piezolith 3000 demonstrated the most favorable stone mass reduction for 500 shock treatments (187.4 ± 45.2 mg). The Sonolith i-sys was found to be significantly less effective than the other lithotripters for all shockwave conditions. Furthermore, performance of the Sonolith i-sys decreased beyond a threshold generator electrode age of 6000 shocks.

CONCLUSIONS

This in vitro study found considerable variability in the ability of lithotripters to fragment synthetic urinary calculi. Synthetic stones were employed to provide a repeatable means of assessing variability in fragmentation efficiency of lithotripters. The Modulith SLX F2 and Piezolith 3000 are broadly equal and resulted in greater fragmentation efficiencies than the Sonolith i-sys. The performance of the Sonolith i-sys deteriorates at 6000 shocks, before the specified lifetime of 20,000 shocks.

Targeted microbubbles: a novel application for the treatment of kidney stones

Kidney stone disease is endemic. Extracorporeal shockwave lithotripsy was the first major technological breakthrough where focused shockwaves were used to fragment stones in the kidney or ureter. The shockwaves induced the formation of cavitation bubbles, whose collapse released energy at the stone, and the energy fragmented the kidney stones into pieces small enough to be passed spontaneously. Can the concept of microbubbles be used without the bulky machine? The logical progression was to manufacture these powerful microbubbles ex vivo and inject these bubbles directly into the collecting system. An external source can be used to induce cavitation once the microbubbles are at their target; the key is targeting these microbubbles to specifically bind to kidney stones. Two important observations have been established: (i) bisphosphonates attach to hydroxyapatite crystals with high affinity; and (ii) there is substantial hydroxyapatite in most kidney stones. The microbubbles can be equipped with bisphosphonate tags to specifically target kidney stones. These bubbles will preferentially bind to the stone and not surrounding tissue, reducing collateral damage. Ultrasound or another suitable form of energy is then applied causing the microbubbles to induce cavitation and fragment the stones. This can be used as an adjunct to ureteroscopy or percutaneous lithotripsy to aid in fragmentation. Randall's plaques, which also contain hydroxyapatite crystals, can also be targeted to pre-emptively destroy these stone precursors. Additionally, targeted microbubbles can aid in kidney stone diagnostics by virtue of being used as an adjunct to traditional imaging methods, especially useful in high-risk patient populations. This novel application of targeted microbubble technology not only represents the next frontier in minimally invasive stone surgery, but a platform technology for other areas of medicine.

[Effectiveness of flexible ureteroscopy versus extracorporeal shock wave lithotripsy for kidney stones treatment]

Primary endpoint was to objective a better effectiveness of flexible ureteroscopy (fURS) compared to extracorporeal shock wave lithotripsy (ESWL) 3 months after treatment of a unique kidney stone from 5 to 20mm. Secondary endpoints were to evaluate effectiveness in subgroup and tolerance. We conducted a prospective comparative randomised trial between May 2012 and February 2014. A computerised tomography was done before treatment and another 3 months after treatment. Of the 30 randomised patients, 8 dropped out from the study and 4 were lost to follow-up. Median time of follow-up was 3.82 months. In per-protocol analysis, success rate was 60% for fURS group versus 28.6% for ESWL group (P=0.29). In intention to treat analysis, success rate was 77.8% in fURS group versus 53.8% in ESWL group (P=0.38). In ESWL group, 5 patients (41.7%) needed a second treatment versus none in fURS group but it was not significant. During follow-up, 1 patient in each group presented a complication. Results of this feasibility study did not allowed to conclude on superiority of a technic. A multicenter study with more important enrollment is necessary considering economic side and tolerance of these treatments.

The success of extracorporeal shock-wave lithotripsy based on the stone-attenuation value from non-contrast computed tomography

Objective

To determine the utility of the urinary stone-attenuation value (SAV, in Hounsfield units, HU) from non-contrast computed tomography (NCCT) for predicting the success of extracorporeal shock-wave lithotripsy (ESWL).

Patients and methods

The study included 305 patients with renal calculi of ⩽30 mm and upper ureteric calculi of ⩽20 mm. The SAV was measured using NCCT. Numerical variables were compared using a one-way analysis of variance with posthoc multiple two-group comparisons. Univariate and multivariate regression analysis models were used to test the preferential effect of the independent variable(s) on the success of ESWL.

Results

Patients were grouped according to the SAV as group 1 (⩽500 HU, 81 patients), group 2 (501–1000 HU, 141 patients) and group 3 (>1000 HU, 83 patients). ESWL was successful in 253 patients (83%). The rate of stone clearance was 100% in group 1, 95.7% (135/141) in group 2 and 44.6% (37/83) in group 3 (P = 0.001).

Conclusions

The SAV value is an independent predictor of the success of ESWL and a useful tool for planning stone treatment. Patients with a SAV ⩾956 HU are not ideal candidates for ESWL. The inclusion criteria for ESWL of stones with a SAV <500 HU can be expanded with regard to stone size, site, age, renal function and coagulation profile. In patients with a SAV of 500–1000 HU, factors like a body mass index of >30 kg/m² and a lower calyceal location make them less ideal for ESWL.

A systematic review and meta-analysis of new onset hypertension after extracorporeal shock wave lithotripsy

OBJECTIVE

Previous studies on the association between extracorporeal shock wave lithotripsy (SWL) and new onset hypertension have only illustrated contradictory results. In order to illustrate the association between SWL and new onset hypertension, a meta-analysis of case-control and cohort studies was conducted.

METHODS

Relevant literature was searched using PubMed, EMBASE, and the Cochrane Central Search Library. A meta-analysis of the association between SWL and new onset hypertension was performed. Studies were pooled, and summary relative risk was calculated. Subgroup analyses were also conducted.

RESULTS

Eleven studies were eligible for our analysis. No statistical significance was detected between SWL and new onset hypertension (RR = 1.06, 95 % CI 0.83-1.35). No association was observed when stratified analyses were performed on age, gender, study design, bilateral SWL, and different machines.

CONCLUSION

Our analysis indicated that no association was found between SWL and the development of hypertension.

The efficacy of tamsulosin therapy after extracorporeal shock-wave lithotripsy for ureteric calculi: A prospective randomised, controlled study

OBJECTIVE

To evaluate whether tamsulosin hydrochloride is effective as an adjunctive medical therapy to increase the effectiveness of extracorporeal shock-wave lithotripsy (ESWL) for treating ureteric stones, and minimises the use of analgesic drugs after the procedure.

PATIENTS AND METHODS

To treat single ureteric stones of 5-15 mm in diameter, 130 patients were treated with ESWL. After treatment, equal numbers of patients were randomly assigned to receive either the standard medical therapy alone (controls) or combined with 0.4 mg tamsulosin daily for ⩽12 weeks. All patients were followed up for 3 months or until an alternative treatment was offered.

RESULTS

At 3 months the treatment was considered to be clinically successful in 55/65 (85%) of those receiving tamsulosin and in 58/65 (89%) of the controls (P = 0.34). When patients were classified according to stone size the success rate was similar in both groups (P = 0.22) for those with a stone of >10 mm. However, ureteric colic was reported in 12% of patients treated with standard therapy but in only 5% of those treated with tamsulosin (P = 0.006). The mean cumulative diclofenac dose was 380 mg/patient in the tamsulosin group and 750 mg/patient in the control group (P = 0.004).

CONCLUSIONS

This study showed the effectiveness of tamsulosin as an adjunctive medical therapy after ESWL for ureteric stones, but it did not improve stone clearance when treating ureteric stones. However, it decreased the use of analgesics and reduced the complication rate, especially for steinstrasse.

Evaluating ESWL-induced renal injury based on urinary TNF-α, IL-1α, and IL-6 levels

Extracorporeal shockwave lithotripsy (ESWL) has dramatically changed the treatment of urinary lithiasis and has been the first treatment option for the majority of patients for more than two decades. Despite its significant benefits, it induces acute renal injury that extends from the papilla to the outer cortex. We evaluated the severity of the inflammatory response to ESWL by measuring the urinary excretion of the cytokines TNF-α, IL-1α, and IL-6. The study included 21 selected patients and 14 control subjects. All patients underwent the same ESWL procedure (2,500 shockwaves at 100 shockwaves/min and 0.039 J from the lithotripter). Urine TNF-α, IL-1α, and IL-6 levels were measured using standard ELISA kits. In the study population (patients and controls), we did not detect TNF-α in the urine samples. The levels of both IL-1α (2.5 pg/ml) and IL-6 (3.8 pg/ml) measured before ESWL were not significantly different from the control group (2.5 and 5.2 pg/ml, respectively; p > 0.05). Twenty-four hours after ESWL, in contrast to IL-1α (4 pg/ml), urine IL-6 (19.7 pg/ml) increased significantly (p < 0.05). Fourteen days after ESWL, IL-1α increased to 5 pg/ml, while IL-6 (7 pg/ml) decreased to the control level. Urine cytokine levels may be used to evaluate the inflammatory response to ESWL. After ESWL, IL-6 levels increased in the early phase, while IL-1α levels increased later. These two markers may be used to measure the severity of inflammation. In contrast to IL-1α and IL-6, urine TNF-α excretion was not increased by ESWL. We believe that the inflammatory response to ESWL can be detected by the urinary excretion of IL-1α for up to 14 days.

Effect of high shock number on acute complication development after extracorporeal shockwave lithotripsy

PURPOSE

We assessed whether high shock number is associated with higher rates of acute complication development after extracorporeal shockwave lithotripsy (SWL).

PATIENTS AND METHODS

A retrospective chart review of 372 patients who underwent 436 SWL procedures at 24 kV using a Medstone STS-T lithotripter (Medstone International Inc., Aliso Viejo, CA) was conducted. Complications occurred within 4 weeks of SWL. Treatments were split into three cohorts based on shock number (<2400, 2401-4000, and >4000). Postoperative sequelae of patients who were stone free and those with residual stone were studied separately. Chi-square tests were used to evaluate the relationship between shock number cohort and postoperative complication development.

RESULTS

SWL treatments recorded for each cohort were 158 (37.4%), 145 (34.4%), and 119 (28.2%), respectively. The short-term complication rate when SWL was successful was 8.3% overall. Complication rate for each cohort was 9.5% (11), 7.8% (5), and 7.2% (7), respectively. When SWL was successful, statistical analysis revealed no significant difference between complication rates and shock number cohort (P=0.63). Complications in patients with a residual stone occurred after 41.4% of treatments and trended upward with shock number cohort, but did not reach statistical significance (P=0.84).

CONCLUSIONS

At high voltage, high shock number was not shown to cause higher rates of short-term postoperative complications, as experienced by patients, when SWL was successful or resulted in a residual stone, yet complication rates associated with residual stone burden were approximately five times as common. Forgoing a higher shock number in the presence of a residual stone may therefore increase the risks of sequelae immediately after SWL.

Recent finding and new technologies in nephrolitiasis: a review of the recent literature

This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.

Extracorporeal shock wave lithotripsy: What is new?

OBJECTIVES

Thirty years after its introduction, extracorporeal shockwave lithotripsy (ESWL) is still first-line treatment for more than half of all urinary tract stones, but machines and treatment strategies have significantly developed over time. In this review, we summarise the latest knowledge about the clinically important aspects of ESWL.

METHODS

We searched PubMed to identify relevant reports and the latest European Association of Urology guidelines, and standard urological textbooks were consulted.

RESULTS

New technical developments include: Twin-head and tandem-pulse shock-wave generators; wide-focus, low-pressure systems; optimised coupling; and automated location and acoustic tracking systems. Indications have been refined, making possible the identification of patients in whom ESWL treatment is likely to fail. By lowering the shock-wave rate, improving coupling, applying abdominal compression, power 'ramping' and postoperative medical expulsion therapy, treatment protocols have been optimised.

CONCLUSIONS

Promising new technical developments are under development, with the potential to increase the stone-free rate after ESWL. For optimal results, the refined indications need to be respected and optimised treatment protocols should be applied.

Extracorporeal shockwave lithotripsy vs. percutaneous nephrolithotomy vs. flexible ureterorenoscopy for lower-pole stones

Objectives

To review previous reports and discuss current trends in extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureterorenoscopy (URS). ESWL was recommended as the first-line treatment for small and intermediate-sized stones in the lower pole, while it is the standard treatment for large stones. However, the stone clearance rate after ESWL seems to be lower than that of stones in other locations. This seems to result from a lower rate of fragment passage, due to anatomical factors.

Methods

Reports on urinary stone disease were reviewed, assessing only publications in peer-reviewed, Medline-listed journals in the English language (publication years 1990–2011).

Results

Recent experience with flexible URS (fURS) for intrarenal stones showed that excellent stone-free rates can be achieved. With increasing experience and technically improved equipment, fURS has become an alternative to ESWL for small and intermediate-sized renal stones. Furthermore, several authors reported successful retrograde treatment for large renal stones, proposing fURS as an alternative to PCNL. However, the major drawbacks are long operating times and commonly, staged procedures, which is why PCNL remains the method of choice for such stones.

Conclusions

Considering the currents trends and evidence, the 2012 update of the European Association of Urology Guidelines on Urolithiasis has upgraded the endourological treatment of kidney stones. Individual factors such as body habitus, renal anatomy, costs and patient preference must be considered.

Which is more important in predicting the outcome of extracorporeal shockwave lithotripsy of solitary renal stones: stone location or stone burden?

PURPOSE

To assess the effect of stone location and burden on the outcome of extracorporeal shockwave lithotripsy (SWL) as a primary treatment of solitary renal stone.

PATIENTS AND METHODS

The study included 438 patients with a solitary renal stone who underwent SWL as a primary treatment for their stones. All were evaluated by plain radiography of the kidneys, ureters, and bladder (KUB), ultrasonography, intravenous urography, or noncontrast enhanced CT before SWL and followed up for 3 months after treatment by KUB radiography and/or ultrasonography. Patients were classified into four groups according to stone location (renal pelvis, lower, middle, and upper calix) and three groups according to stone burden (≤ 1 cm(2), 1.1-2 cm(2), and >2 cm(2)). Treatment outcome was considered successful if no residual fragments (stone free) or clinically insignificant nonobstructing residuals less than 4 mm remained after 3 months of follow-up.

RESULTS

The mean age of the patients was 45.1 ± 12.5 years. The mean stone burden, number of sessions, and shockwaves for the whole study were 1.3 ± 0.49 cm(2), 2.1 ± 0.7 sessions, and 5616.6 ± 2017.4 shockwaves, respectively. The stone-free rate of the study was 65.1%. The stone-free rates of the stones in the renal pelvis, lower, middle, and upper calices were 72.4%, 56%, 55.6%, and 69%, respectively. The stone-free rate of the stones ≤ 1 cm(2), 1.1 to 2 cm(2), and >2 cm(2) was 50.2%, 39.6%, and 10.2%, respectively (P<0.05).

CONCLUSION

Stone burden rather than stone location is considered as a predicting factor for the outcome of SWL in a solitary renal stone, especially in the renal pelvis and lower calix.

[Single-session extracorporeal shock wave lithotripsy for urinary calculi: factors predicting success after three weeks of follow-up]

INTRODUCTION

The aim of this study was to identify predictive factors of success following a single-session of shock wave lithotripsy (SWL) at 3 weeks of follow-up in our center.

MATERIAL AND METHODS

The medical records of 116 patients with solitary urinary calculi who underwent single-session SWL in our department between October 2007 and August 2009 were reviewed. All preoperative unenhanced computed axial tomographies were reviewed by two radiologists blinded to clinical outcome. Success was defined as complete clearance or the persistence of fragments ≤ 2 mm on a plain film at 3 weeks of follow-up. The impact of clinical and radiological factors on success was assessed by univariate and multivariate analyses.

RESULTS

The single-session SWL success rate at 3 weeks was 49.1%. Stone size <8 mm, stone area < 30 mm(2), stone location (mid- and distal ureter), stone density <1000 HU and intraoperative fragmentation showed a significant association with SWL success in the univariate analysis (p<0.05). Stone area (OR 2.9), ureteral stone location (OR 3.4) and intraoperative fragmentation (OR 4.2) were the only predictors of success in the multivariate analysis.

CONCLUSIONS

Stone area and ureteral stone location provide important information when deciding about the indication of a SWL in a patient with stone disease. However, successful resolution of only half of the cases after a single session at 3 weeks in our series undermines the relevance of informing patients about the potential need for additional treatment.

High-frequency jet ventilation is beneficial during shock wave lithotripsy utilizing a newer unit with a narrower focal zone

INTRODUCTION

High-frequency jet ventilation (HFJV) during shock wave lithotripsy (SWL) has been reported using older lithotripsy units with larger focal zones. We investigated how HFJV affects the clinical parameters of SWL using a newer lithotripsy unit with a smaller focal zone.

METHODS

We reviewed all patients who underwent SWL by a single surgeon (KVA) from July 2006 until December 2007 with the Siemens Lithostar Modularis (Siemens AG, Erlangen, Germany). Either HFJV or conventional anesthetic techniques were used based on the anesthesiologists' preference. Preoperative imaging was reviewed for stone size, number and location. Total operating room time, procedure time, number of shocks and total energy delivery were analyzed. Postoperative imaging was reviewed for stone-free rates.

RESULTS

A total of 112 patients underwent SWL with 80 undergoing conventional anesthesia, and 32 with HFJV. Age, body mass index, preoperative stone size and number were not significantly different between the groups. The HFJV group required significantly less total shocks (3358 vs. 3754, p = 0.0015) and total energy (115.8 joules vs. 137.2 joules, p = 0.0015). Total operating room time, SWL procedure time and postoperative stone-free rates were not significantly different.

CONCLUSIONS

Previous studies using older SWL units with larger focal zones have demonstrated that HFJV can be effective in reducing total shocks and total energy. Our data is consistent with these studies, but also shows benefit with newer units that have narrower focal zones.

Shock wave lithotripsy is not predictive of hypertension among community stone formers at long-term followup

PURPOSE

Concern exists over the subsequent development of hypertension after shock wave lithotripsy for the treatment of symptomatic urolithiasis. Referral bias and lack of long-term followup have been limitations of prior studies.

MATERIALS AND METHODS

We identified all Olmsted County, Minnesota residents with a diagnosis of urolithiasis from 1985 to 2008. The charts were electronically queried for hypertension and obesity by diagnostic codes, and use of shock wave lithotripsy by surgical codes. All patients first diagnosed with hypertension before or up to 90 days after the first documented kidney stone were considered to have prevalent hypertension and were excluded from analysis. Cox proportional hazards models were used to assess the association of shock wave lithotripsy with a subsequent diagnosis of hypertension.

RESULTS

We identified 6,077 patients with incident urolithiasis with more than 90 days of followup. We excluded 1,295 (21.3%) members of the population for prevalent hypertension leaving 4,782 patients with incident urolithiasis for analysis. During an average followup of 8.7 years new onset hypertension was diagnosed in 983 (20.6%) members of the cohort at a mean of 6.0 years from the index stone date. Only 400 (8.4%) patients in the cohort were treated with shock wave lithotripsy. There was no significant association between shock wave lithotripsy and the development of hypertension in univariate (p = 0.33) and multivariate modeling controlling for age, gender and obesity (HR 1.03; 95% CI 0.84, 1.27; p = 0.77).

CONCLUSIONS

In a large population based cohort of kidney stone formers we failed to identify an association between shock wave lithotripsy and the subsequent long-term risk of hypertension.

Effect of output voltage distribution on stone comminution efficiency during shockwave lithotripsy in renal or ureteropelvic junction stones: a preliminary study

OBJECTIVE

This study evaluated stone comminution efficiency according to the distribution of the lithotripter output voltage during extracorporeal shockwave lithotripsy (SWL) of renal or ureteropelvic junction (UPJ) stones.

MATERIAL AND METHODS

Sixty-two patients with a single radiopaque renal or UPJ stone of surface area about 50-400 mm(2) were prospectively randomized to receive a total of 2400 shocks per session according to one of three shock protocols: group A, output voltage was increased from 25% to 35% to 45% with 800 shocks per voltage; group B, constant output voltage of 35%; group C, decreasing output voltage from 45% to 35% to 25%. SWLs were carried out using a fourth generation electroconductive lithotripter, the Sonolith Vision, without anesthesia. The stone-free (SF) and success (SF + clinically insignificant residual fragment) rates were assessed.

RESULTS

Patient demographics, body mass index, stone burden, laterality and stone locations were comparable among the three groups. There were no differences in the cumulative success rates (30%, 32% and 35% after the first session for groups A, B and C, respectively; 65%, 50% and 65% after the second session; and 80%, 68% and 75% after the third session). The cumulative SF rates and complications showed no differences among the three groups.

CONCLUSIONS

In this preliminary study, manipulation of the lithotripter output voltage distribution did not affect stone comminution efficiency for renal or UPJ stones. This finding should be confirmed by larger studies including more patients.

SWL is More Cost-Effective than Ureteroscopy and Holmium:YAG Laser Lithotripsy for Ureteric Stones: A Comparative Analysis for a Tertiary Referral Centre

Background:

To identify the most cost-effective treatment for ureteric stones ≤15 mm in our department, by using an economic model to compare the total cost of shockwave lithotripsy (SWL) versus ureteroscopy with Holmium:YAG laser lithotripsy (URSL).

Patients and methods:

Data for patients treated with the same lithotriptor were retrospectively analyzed. The financial department provided data about the cost of procedures. This model accepted a 100% stone-free rate for URSL in outpatients, and a 50% rate of insertion of a ureteric stent. The cost for each procedure to render a patient stone-free was estimated by the following equations: costSWL = cost(initial SWL session) + [cost(SWL session) × retreatment rate] + [cost(URSL) × SWL failure rate] + [cost(stent insertion and removal) × rate] + [cost(KUB film) × 4] costURSL = cost(URSL) + [cost(stent removal) × 50%] + [cost(KUB film) × 2]

Results:

Records of 228 patients with previously untreated solitary radiopaque ureteric stones ≤15 mm were reviewed. The total cost for SWL (cSWL) was £1491/patient, while the total cost for URSL (cURSL) was £2195/patient. The difference was highest in the upper ureter (over £1000), and lowest in the distal part (URSL about 40% more expensive). For lower ureteric stones >10 mm, SWL was over £500 more expensive than URSL.

Conclusion:

Using data from the department to calculate cost-effectiveness for ureteric stones ≤15 mm a difference in favour of SWL versus URSL was found. Uniform guidelines incorporating cost are impossible considering differences between countries; each centre should probably assess their data individually.

Failure after shockwave lithotripsy: is outcome machine dependent?

AIM

To investigate the issue of shockwave lithotripsy failure by studying the effect of machine crossover to the Technomed Sonolith Vision (TSV) lithotriptor in patients with previously unsuccessfully treated renal stones with the Dornier Compact Delta (DCD). Records were examined for the period between 1998 and 2006. Parameters analysed were: size, multiple/single stones, location, treatments/stone.

RESULTS

Seventy-six patients fulfilled the inclusion criteria. Following lithotripsy with the TSV, the stone-free rate (SFR) at 3 months was 56.7%, and the success rate (stone-free and fragments < or = 4 mm, SR) 86.7%. Twenty-two patients had multiple stones and the majority of the stones were located in the lower calyx (59.2%). Mean size was 8.9 mm prior to treatment with the TSV machine (10.2 mm for DCD). Further analysis followed in a subgroup of 42 patients of the same stone size (+/-2 mm) before and after DCD sessions. Mean stone size was 7 mm. The SFR was 61.9% (62.9% vs. 40.9% for single and multiple stones), and the SR was 88.1%. No difference in SFR was found for single or multiple stones in any of the two groups.

CONCLUSIONS

The term 'extracorporeal shockwave lithotripsy (ESWL)-resistant stones' needs to be re-examined, as treatment with a different lithotriptor was successful in a group of stones where another machine had failed. Lithotripters with different shock wave characteristics may result in difference in the results of ESWL. Future research in ESWL should focus on stone characteristics and development of machines with the ability to adapt to specific stone features.

Shock wave lithotripsy for renal stones is not associated with hypertension and diabetes mellitus

OBJECTIVES

To clarify the influences of shock wave lithotripsy (SWL) treatments for renal and ureteropelvic junction stones on new onsets of hypertension and diabetes mellitus (DM).

METHODS

We compared the new onsets of hypertension and DM after SWL in renal and ureteral stone groups. The renal stone group consisted of 772 patients treated with SWL, who had a possibility of renal and pancreatic shock wave damage. The ureteral stone group consisted of 505 patients treated with SWL, who were unlikely to have suffered SWL damage in the kidney and pancreas areas. Both treatment groups received SWL between 1984 and 1994.

RESULTS

The rates of new onset of hypertension in the renal stone and ureteral stone groups were 22.8% and 20.0% in men and 23.1% and 20.5% in women, respectively. The rates of new onset of DM in the renal stone and ureteral stone groups were 7.4% and 11.0% in men and 8.7% and 8.7% in women, respectively. There was no significant difference in the new onsets of hypertension and DM between renal and ureteral stone groups depending on each age decade or sex. Treatment for renal stone was not a significant risk factor for new onsets of hypertension and DM by logistic regression analysis.

CONCLUSIONS

Our findings suggest that SWL treatment for renal and UPJ stones might not be associated with new onset of hypertension or DM.

Cost-Effectiveness of Medical Expulsive Therapy Using Alpha-Blockers for the Treatment of Distal Ureteral Stones

OBJECTIVE

Medical expulsive therapy (MET) has recently emerged as an efficacious and safe option for the initial management of ureteral stones. The objective of this study was to assess the cost-effectiveness of MET compared with conservative therapy for the treatment of ureteral stones using international cost data from the United States and four European countries.

MATERIAL AND METHODS

A decision analysis model was built with the use of TreeAge Pro 2004 software with linear success rate assumptions. The likelihood of spontaneous passage of ureteral stones according to their size and location was estimated with the use of data derived from a published meta-analysis. The estimated cost of ureteroscopy (URS) in the United States ($4973) was based on the mean cost of 121 consecutive cases performed at a large metropolitan hospital. URS costs for other countries were obtained from a published international survey. The cost of tamsulosin ($2.08 per day), currently the most commonly used medical expulsive agent, was estimated as a mean of the costs obtained from two national pharmacy chains. MET and conservative therapies were compared with the use of one-way and two-way sensitivity analyses.

RESULTS

In the United States, MET using tamsulosin resulted in a $1132 cost advantage over observation. MET maintained its cost advantage even in countries where the cost of URS is much lower than in the United States. Two-way sensitivity analysis showed that MET remained cost-effective even with very low rates of spontaneous passage, minimal benefit of MET, or low cost of URS.

CONCLUSION

MET is a cost-effective strategy for the management of distal ureteral stones--even those with a low rate of spontaneous passage--providing another incentive for initial "facilitated observation" before embarking on surgical intervention.