Quantitative Assessment of Effectiveness of Ultrasonic Propulsion of Kidney Stones

Purpose: Ultrasonic propulsion is an investigative modality to noninvasively image and reposition urinary stones. Our goals were to test safety and effectiveness of new acoustic exposure conditions from a new transducer, and to use simultaneous ureteroscopic and ultrasonic observation to quantify stone repositioning. Materials and Methods: During operation, ultrasonic propulsion was applied transcutaneously, whereas stone targets were visualized ureteroscopically. Exposures were 350 kHz frequency, ≤200 W/cm2 focal intensity, and ≤3-second bursts per push. Ureteroscope and ultrasound (US) videos were recorded. Video clips with and without stone motion were randomized and scored for motion ≥3 mm by independent reviewers blinded to the exposures. Subjects were followed with telephone calls, imaging, and chart review for adverse events. Results: The investigative treatment was used in 18 subjects and 19 kidneys. A total of 62 stone targets were treated ranging in size from a collection of "dust" to 15 mm. Subjects received an average of 17 ± 14 propulsion bursts (per kidney) for a total average exposure time of 40 ± 40 seconds. Independent reviewers scored at least one stone movement ≥3 mm in 18 of 19 kidneys (95%) from the ureteroscope videos and in 15 of 19 kidneys (79%) from the US videos. This difference was probably because of motion out of the US imaging plane. Treatment repositioned stones in two cases that would have otherwise required basket repositioning. No serious adverse events were observed with the device or procedure. Conclusions: Ultrasonic propulsion was shown to be safe, and it effectively repositioned stones in 95% of kidneys despite positioning and access restrictions caused by working in an operating room on anesthetized subjects.

Endourologic Management (PCNL, URS, SWL) of Stones in Solitary Kidney: A Systematic Review from European Association of Urologists Young Academic Urologists and Uro-Technology Groups

Introduction: Urolithiasis in solitary kidney (SK) presents significant management dilemma as any insult to the kidney or its drainage can lead to significant morbidity. The treatment options include shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), and ureteroscopy (URS). Our aim was to conduct a systematic review of literature on all available endourologic techniques reporting on the management of stones in an SK. Materials and Methods: We conducted a systematic review according to the Cochrane and PRISMA checklist for all English-language articles from inception to December 2018. All studies with a minimum of 10 patients that reported on endourologic management (SWL, PCNL, or URS) were included. Data were extracted for patient and stone demographics, outcomes including stone-free rate (SFR), adverse events, and renal function. Results: After an initial search of 553 articles, 27 were included for the final review (10 PCNL, 1 mini-PCNL, 9 URS, 1 SWL, and 6 comparative studies). The choice of treatment seemed to be based on stone size, with PCNL, URS, and SWL offered for mean stone sizes between 25-50, 10-28, and 12-15 mm, respectively. PCNL, URS, and SWL were reported in 1445, 792, and 186 patients, respectively, with a final SFR of 67%-97.7%, 43%-100%, and 73%-80% and a complication rate of 26.4%, 15%, and 16.7% across the three groups. The renal function deterioration was reported in 4/16 PCNL studies and in 1/15 URS studies, while it remained unaffected in the SWL study. Conclusions: Our review shows a rise of endourologic techniques in the management of stones in SK. Although PCNL was used for larger stones, it had a higher risk of major complications, including blood transfusion. While a good SFR was obtained for patients irrespective of the treatment modality, the selected intervention needs to be balanced with its safety profile and the need for ancillary procedures.

[Multidisciplinary approach in urology. Laser technologies: faster, simpler, more efficient]

Laser technology has taken a place among the methods of treatment of various urological diseases. The new laser devices are being developed in addition to commonly used. Physicists of the russian NTO "IRE Polus" in collaboration with doctors from Sechenov University have developed a new generation laser device - thulium fiber laser. It has been actively used since 2017 for laser enucleation of prostate. Later the laser was used for treatment of bladder tumor, lithotripsy. The device has already managed to prove its efficacy in in-vitro experiments and clinical practice surpassing foreign analogues.

The laser of the future: reality and expectations about the new thulium fiber laser-a systematic review

The Holmium:yttrium-aluminum-garnet (Ho:YAG) laser has been the gold-standard for laser lithotripsy over the last 20 years. However, recent reports about a new prototype thulium fiber laser (TFL) lithotripter have revealed impressive levels of performance. We therefore decided to systematically review the reality and expectations for this new TFL technology. This review was registered in the PROSPERO registry (CRD42019128695). A PubMed search was performed for papers including specific terms relevant to this systematic review published between the years 2015 and 2019, including already accepted but not yet published papers. Additionally, the medical sections of ScienceDirect, Wiley, SpringerLink, Mary Ann Liebert publishers, and Google Scholar were also searched for peer-reviewed abstract presentations. All relevant studies and data identified in the bibliographic search were selected, categorized, and summarized. The authors adhered to PRISMA guidelines for this review. The TFL emits laser radiation at a wavelength of 1,940 nm, and has an optical penetration depth in water about four-times shorter than the Ho:YAG laser. This results in four-times lower stone ablation thresholds, as well as lower tissue ablation thresholds. As the TFL uses electronically-modulated laser diodes, it offers the most comprehensive and flexible range of laser parameters among laser lithotripters, with pulse frequencies up to 2,200 Hz, very low to very high pulse energies (0.005-6 J), short to very long-pulse durations (200 µs up to 12 ms), and a total power level up to 55 W. The stone ablation efficiency is up to four-times that of the Ho:YAG laser for similar laser parameters, with associated implications for speed and operating time. When using dusting settings, the TFL outperforms the Ho:YAG laser in dust quantity and quality, producing much finer particles. Retropulsion is also significantly reduced and sometimes even absent with the TFL. The TFL can use small laser fibers (as small as 50 µm core), with resulting advantages in irrigation, scope deflection, retropulsion reduction, and (in)direct effects on accessibility, visibility, efficiency, and surgical time, as well as offering future miniaturization possibilities. Similar to the Ho:YAG laser, the TFL can also be used for soft tissue applications such as prostate enucleation (ThuFLEP). The TFL machine itself is seven times smaller and eight times lighter than a high-power Ho:YAG laser system, and consumes nine times less energy. Maintenance is expected to be very low due to the durability of its components. The safety profile is also better in many aspects, i.e., for patients, instruments, and surgeons. The advantages of the TFL over the Ho:YAG laser are simply too extensive to be ignored. The TFL appears to be a real alternative to the Ho:YAG laser and become a true game-changer in laser lithotripsy. Due to its novelty, further studies are needed to broaden our understanding of the TFL, and comprehend the full implications and benefits of this new technology, as well its limitations.

Shock-Induced Damage and Dynamic Fracture in Cylindrical Bodies Submerged in Liquid

Understanding the response of solid materials to shock loading is important for mitigating shock-induced damages and failures, as well as advancing the beneficial use of shock waves for material modifications. In this paper, we consider a representative brittle material, BegoStone, in the form of cylindrical bodies and submerged in water. We present a computational study on the causal relationship between the prescribed shock load and the resulting elastic waves and damage in the solid material. A recently developed three-dimensional computational framework, FIVER, is employed, which couples a finite volume compressible fluid solver with a finite element structural dynamics solver through the construction and solution of local, one-dimensional fluid-solid Riemann problems. The material damage and fracture are modeled and simulated using a continuum damage mechanics model and an element erosion method. The computational model is validated in the context of shock wave lithotripsy and the results are compared with experimental data. We first show that after calibrating the growth rate of microscopic damage and the threshold for macroscopic fracture, the computational framework is capable of capturing the location and shape of the shock-induced fracture observed in a laboratory experiment. Next, we introduce a new phenomenological model of shock waveform, and present a numerical parametric study on the effects of a single shock load, in which the shock waveform, magnitude, and the size of the target material are varied. In particular, we vary the waveform gradually from one that features non-monotonic decay with a tensile phase to one that exhibits monotonic decay without a tensile phase. The result suggests that when the length of the shock pulse is comparable to that of the target material, the former waveform may induce much more significant damage than the latter one, even if the two share the same magnitude, duration, and acoustic energy.

Vaporizing Effect of the Popcorn Technique for Laser Lithotripsy: Comparing the Different Settings of High Energy in a Caliceal Model

Objective: To assess the effectiveness of laser lithotripsy in different holmium:yttrium aluminum garnet (Ho-YAG) laser settings with a wide range of energies, frequencies, and power. Materials and Methods: Two types of phantom stones were utilized, including soft stone, which mimics uric acid stone, and hard stone, which mimics calcium oxalate monohydrate stone. The stones were made into a round shape measuring 10 mm in diameter. The lithotripsy settings were 1 J × 20 Hz, 2 J × 10 Hz, 1.5 J × 20 Hz, 3 J × 10 Hz, and 2 J × 20 Hz. The lithotripsy was conducted in a caliceal model with a 2-mm filter. All stone vanishing from the artificial calix was an end point of the experiment. All fragments that passed through the filter of each setting were dried and weighed to calculate the vaporizing effect as well as to compare among the different settings. Laser fiber degradation was compared by using these settings. Results: Disintegration efficiency was determined by time consumption and the amount of vaporized stone. The best time consumption was 8 min 51 sec for 2 J × 20 Hz for hard stone and 5 min 13 sec for this setting for soft stone. The most vaporizing effect for hard stone was 92.19% for 2 J × 20 Hz and 87.30% for this setting for soft stone. The most fiber tip degradation was 28 mm for 3 J × 10 Hz for hard stone and 4 mm for 1.5 J × 20 Hz for soft stone. Conclusion: The study revealed that the best setting for hard stone was 2 J × 20 Hz, which was the fastest for achieving maximum vaporization, whereas fiber degeneration was comparable to others. For soft stone, there was no difference among the settings.

Long-term outcome after flexible ureteroscopy with holmium laser for simultaneous treatment of a single renal cyst and ipsilateral renal stones

Objective

To assess the long-term outcome of simultaneous treatment of a single renal cyst and ipsilateral stones with transurethral flexible ureteroscopy (FURS) lithotripsy and internal cyst drainage.

Methods

Patients who underwent simultaneous treatment with FURS lithotripsy and internal cyst drainage in our institution between July 2014 and September 2017 were enrolled. The cyst wall was identified endoscopically and a 1–3-cm window was created in the wall using a holmium laser. The proximal end of a double-J stent was placed in the cystic cavity to facilitate internal drainage.

Results

Thirteen patients underwent simultaneous treatment. No intraoperative complications with Clavien grading score >2 were noted in any patients. Mean stone burden and cyst diameter were 1.6 (range: 0.9–2.5) cm and 5.8 (range: 3.0–7.1) cm, respectively. Stone-free rates after single and complementary procedures were 84.6% and 92.3%, respectively. During the mean 33.1-month follow-up period (range: 17–54 months), seven patients (53.8%) achieved full resolution of renal cysts, five patients (38.5%) maintained >50% size reduction, and one patient (7.6%) experienced recurrence at 18 months postoperatively.

Conclusions

FURS with a holmium laser may constitute a safe and effective alternative procedure for simultaneous treatment of a single renal cyst and ipsilateral stones.

Short-term changes in renal function in children and adolescents undergoing extracorporeal shock wave lithotripsy

Aim To identify short-term effects of extracorporeal shock wave lithotripsy (ESWL) on renal function in children and adolescents with single kidney stones. Methods In a 4-year period 30 children (15 boys and 15 girls) from 10 to 18 years of age were treated for unilateral renal stones with ESWL. Inclusion criteria were: up to 18 years of age, kidney stone (from 4 to 20 mm in diameter) visible on X-ray, first ESWL treatment, unilateral lithotripsy treatment without previous kidney surgery, patients without infravesical obstruction, patients without proven urinary infection, repeated use of one (the same) analgesic, patients without anticoagulant and antihypertensive therapy, patients without use of nephrotoxic drugs prior to and during the treatment, normal blood pressure, non-pregnancy patients with normal renal function. Serum enzymes (alkaline phosphatase, lactate dehydrogenase), cystatin C, serum and urine electrolytes (sodium, potassium, chloride), and urine neutrophil gelatinase-associated lipocalin (uNGAL) were tested before, on the first and fifth day after the treatment. Results An increase of alkaline phosphatase and lactate dehydrogenase was statistically significant on day 1 (p<0.05) and values returned to normal on day 5. Serum cystatin C level was also significantly increased during the first four days after ESWL treatment (p<0.05) and returned to baseline on post-treatment day 5. There was a statistically significant difference in the level of uNGAL in urine before and 24 hours after ESWL treatment (p<0.05). Conclusion The ESWL is a safe and curative procedure for the treatment of kidney stones in children and adolescents with no evidence of serious adverse effects on renal function.

A Novel Laser Lithotripsy System with Automatic Real-Time Urinary Stone Recognition: Computer Controlled Ex Vivo Lithotripsy is Feasible and Reproducible in Endoscopic Stone Fragmentation

PURPOSE

Urinary stone treatment has been strongly influenced by advances in technology. Nevertheless, the photonic characteristics of stones as the treatment target have been neglected. Monitoring fluorescence spectra is sufficient for automatic target differentiation and laser feedback control as previously described. We investigated the characteristics of fluorescence signals and the clinical practicability of real-time laser feedback control during lithotripsy.

MATERIALS AND METHODS

Fluorescence excitation light was superimposed on a holmium laser beam into the treatment fiber. Spectra were recorded and signal amplitude changes were analyzed during increases in distance between the fiber tip and the stone to identify the optimal threshold level for stone recognition. Ho:YAG lithotripsy was performed under in vitro surgical conditions in porcine tissue while our feedback system autonomously controlled the laser impulse release during lithotripsy. The tissue was then endoscopically and macroscopically examined for laser induced lesions.

RESULTS

Mean ± SD autofluorescence signal amplitudes from urinary stone samples varied between 142 ± 29 and 1,521 ± 152 ADU while tissue and endoscope coating emission was negligible. Signal amplitude decreased rapidly at distances larger than 1 to 2 mm. Clinically reliable threshold values for target recognition could be set to prevent laser pulse emission if the stone was out of range or urothelial tissue might be harmed by laser irradiation. We observed no incorrectly released laser pulse or injury to tissue during autonomously controlled holmium laser lithotripsy.

CONCLUSIONS

Our laboratory study strengthens the evidence that tracking real-time autofluorescence spectra during endoscopic stone surgery via automatic feedback control of the laser impulse release may become a potentially useful clinical tool for surgeons who navigate in the upper urinary tract.

Novel balloon technologies to minimize dissection of peripheral angioplasty

INTRODUCTION

Percutaneous transluminal angioplasty (PTA) currently remains the endovascular treatment of choice in a large percentage of patients suffering from peripheral artery disease (PAD). However, the mechanism of angioplasty itself can cause some extent of arterial dissection leading to early vessel restenosis/reocclusion. Current endovascular imaging studies have reported a higher rate of arterial dissection than previously reported in literature and advocated the correlation of dissection with poor patency. Thus, there is the need of developing devices to minimize dissection and bailout stenting.

AREAS COVERED

The present review focuses on newly-developed balloon angioplasty technologies designed to minimize arterial wall distress and consequently the rate of dissections. Available literature regarding three new specialty balloons is being reviewed, highlighting their value and limitations. Authors' future perspective about the benefits of utilizing specialty balloons towards a metal free and dissection free future is also provided.

EXPERT OPINION

By understanding the mechanism of angioplasty and thus developing devices which cause minimal or no arterial wall distress, the rate of dissections and bailout stenting can be minimized and long-term clinical outcomes of endovascular therapy can be optimized.

Change of Trends in the Treatment Modality for Pediatric Nephrolithiasis: Retrospective Analysis of a US-Based Insurance Claims Database

Purpose: The objective of this study was to show the prevalence and investigate treatment trends of pediatric nephrolithiasis based on a large population of U.S. insurance individual's data. Materials and Methods: This research involved a retrospective observational cohort study. Administrative claims data were extracted from the IBM^® MarketScan^® Research Database. We included all patients newly diagnosed with nephrolithiasis, aged <18 years old at the time of diagnosis from January 1, 2007, to December 31, 2014. The patient cohort with nephrolithiasis was selected using the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) code for nephrolithiasis. Each treatment method was searched by Current Procedural Terminology (CPT) code. Results: A total of 28,014 patients were found to have nephrolithiasis in our cohort. Of nephrolithiasis patients, 701 (2.5%) patients were treated by surgical methods. The mean age of patients at the time of treatment was 13 years old. Extracorporeal shockwave lithotripsy (SWL) was the most used treatment modality during the period. SWL was performed in 66% of patients. The number of cases of SWL did not tend to change according to year, whereas retrograde intrarenal surgery (RIRS) tended to increase from 15% to 31%. Percutaneous nephrolithotripsy (PCNL) decreased from 13% to <10 cases. The number of open surgeries was very small and did not show any tendency. Conclusion: During the study period, SWL is stable. RIRS has become more popular in treating renal stones, whereas PCNL has decreased. These results suggest that the RIRS has become more popular than PCNL in treating large renal stones.

Risk factors for ureteroscopic lithotripsy: a case-control study and analysis of 385 cases of holmium laser ureterolithotripsy

Introduction

Ureteroscopic lithotripsy has become the first choice for the treatment of middle and lower ureteral stones, but it still has a certain rate of surgical failure. Here we aimed to determine the factors that may affect the success rate of holmium laser ureterolithotripsy (HLU) and provide the basis and guidance for its future use.

Aim

To evaluate the risk factors for HLU failure.

Material and methods

The clinical data of 385 patients undergoing holmium laser ureterolithotripsy from 2009 to 2012 were retrospectively reviewed to analyze the impact of gender, age, stone side, stone size, stone location, stone number, degree of hydronephrosis, stone impaction, previous extracorporeal shock lithotripsy (ESWL), and associated urinary tract infection (UTI) on the success or failure of surgery.

Results

Surgical success was achieved in 338 (87.8%) patients versus surgical failure in 47 (12.2%) patients. Univariate analysis revealed that the degree of hydronephrosis (p = 0.024), stone impaction (p = 0.003), stone location (p = 0.012), and previous ESWL (p = 0.037) were risk factors for surgical failure. Multivariate logistic regression revealed that stone impaction (odds ratio (OR) = 2.66; p = 0.018) and stone location (OR = 2.11; p = 0.013) were significantly associated with surgical failure. Since some cases of ureterostenosis developed postoperatively, we continued follow-up. The patients had the stent for a year and underwent regular follow-up checks until 5 years. No cases of ureterostenosis recurred.

Conclusions

Ureteroscopic lithotripsy is a safe procedure with few complications. Stone impaction and proximal location are the risk factors for its failure.

Shockwave Intravascular Lithotripsy of Calcified Coronary Lesions in ST-Elevation Myocardial Infarction: First-in-Man Experience

We present the first cases of Shockwave intravascular lithotripsy (S-IVL; Shockwave Medical), a novel coronary calcium modification device, being used in patients undergoing percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI). The 3 presented cases include an upfront use of S-IVL in a right coronary artery, an in-stent restenosis, and a community cardiac arrest/STEMI equivalent where S-IVL was used as a bail-out technique to facilitate stent delivery in a tortuous calcified vessel.

Radiation-free flexible ureteroscopy for kidney stone treatment

Objectives: To evaluate the safety and effectiveness of flexible ureterorenoscopy (fURS) with holmium laser lithotripsy for treating kidney stones without fluoroscopy as method of best practice for patients and endourologists.

Patients and Methods: All patients treated for kidney stones by fURS with holmium laser lithotripsy from February 2016 to February 2017 were retrospectively evaluated. The patients’ demographic characteristics, stone features (size, number, and location), surgical variables (use of fluoroscopy, operative and fluoroscopy time), complications, and success rate (employing stone-free rate [SFR]), were included in the analysis.

Results: In all, 100 patients met the inclusion criteria: 33 fURS were performed under fluoroscopy (Group 1) and 67 without it (Group 2). The mean operating time was 94.33 vs 98.29 min (P = 0.888), respectively. The mean stone volume was 78.5 vs 82.4 mL (P = 0.885), respectively. The SFR was 63.6% and 64.2% (P = 0.771), the perioperative complications rate was 18.2% vs 11.9% (P = 0.285), and the postoperative complications rate was 24.2% and 10.4%, in groups 1 and 2 respectively (P = 0.174).

Conclusions: fURS with holmium laser lithotripsy without fluoroscopy was a feasible and safe treatment for kidney stones. There was no difference between the use of fluoroscopy or not regarding complications or SFR. Thus, we can reduce the risks of radiation exposure to patients and medical staff whilst maintaining surgical success. However, multicentre randomised controlled studies are necessary to evaluate fluoroless URS further and to confirm our present results.

Abbreviations: PTFE: polytetrafluoroethylene; SFR: stone-free rate; (f)URS: (flexible) ureterorenoscopy/ureterorenoscopies; US: ultrasonography

Impact of Case Volume on Shock Wave Lithotripsy Outcomes: Data from the National Shock Wave Lithotripsy Database of New Zealand

Purpose: To assess the impact of individual operator case volume on shock wave lithotripsy (SWL) treatment outcomes in more than 9000 stone cases over a 20-year period in New Zealand. Materials and Methods: Stone cases treated with SWL on the Mobile Medical Technology (MMT) vehicle between June 19, 1995, and December 1, 2014, were identified. Data collection was undertaken prospectively for patient, stone, and treatment characteristics, and retrospectively for treatment outcomes. Multivariate analysis using binary logistic regression was undertaken to assess whether radiographer stone case volume (stones/year) was an independent predictor of SWL success (stone free or clinically insignificant residual fragments ≤4 mm at follow-up). Results: Sixteen radiographers delivered treatment to the included cohort (9039 stone cases), with a median case volume (stones/year) of 73 (range: 37-197) and median total of 425 stones treated (range: 71-1721). The two radiographers with highest case volumes achieved the highest success rates. Radiographer case volume (stones/year) was independently associated with SWL success (odds ratio [OR]: 1.004, 95% confidence interval [CI]: 1.003-1.005, p < 0.0001) and reduced need for post-SWL hospital admission (OR: 0.997, 95% CI: 0.994-1.000, p = 0.028), but there was no associated decrease in post-SWL urosepsis (OR: 0.999, 95% CI: 0.974-1.025, p = 0.941), perinephric hematoma (OR: 1.003, 95% CI: 0.985-1.020, p = 0.778), or need for auxiliary procedures (OR: 1.000, 95% CI: 0.998-1.002, p = 0.871). Conclusions: SWL success rates can be improved by increasing the frequency of cases performed by individual operators. In this multicenter cohort of more than 9000 stone cases treated over a 20-year period, the best outcomes were seen for those radiographers performing >150 cases per year.

[Role of biomarkers of acute kidney damage during lithotripsy of high-density stones]

AIM

To obtain the information about functional state of kidneys in patients with urolithiasis before and after treatment, as well as to study the damaging effect of different types of energy used for fragmentation of high-density stones.

MATERIALS AND METHODS

A total of 105 patients aged from 25 to 62 years with high-density stones were undergone to lithotripsy. In Group 1 (n=38), Group 2 (n=32) and Group 3 (n=35) contact laser lithotripsy, contact ultrasound lithotripsy and extracorporeal shock-wave lithotripsy was used, respectively. In all cases the clinical and biochemical blood and urine tests were performed as well as leukocyte migration inhibition test, selective proteinuria, a urine level of inteleukin-18 (IL-18) and urine NGAL (lipocalin-2) were assessed. The first examination was done the day before lithotripsy and the next ones were performed after 3 hours, on the 1st and 5th day after the intervention.

RESULTS

In all cases dense unilateral kidney stones of size 0.8-2 cm were detected. The stone-free rate after contact lithotripsy was 92.8%. After ESWL, the stone-free rate after two weeks was 94.9%. The average duration of lithotripsy in the Group 1, 2 and 3 was 40+/-3.8 min, 35+/-2.3 min and 32+/-3.6 min, respectively. Based on the level of biomarkers of AKI, laser lithotripsy allows to achieve stone fragmentation with the least damage.

CONCLUSION

Our study proves that IL-18, NGAL, leukocyte migration inhibition test and selective proteinuria allows to diagnose AKI at early stages, as well as to objectively assess the functional state of the kidneys after lithotripsy. The obtained data proves that laser lithotripsy is the safest method as assessed by damaging effects on the kidney parenchyma.

Fragments and dust after Holmium laser lithotripsy with or without "Moses technology": How are they different?

Urinary stones can be readily disintegrated by Holmium:YAG laser (Holmium laser lithotripsy), resulting in a mixture of small stone dust particles, which will spontaneously evacuate with urine and larger residual fragments (RF) requiring mechanical retrieval. Differences between fragments and dust have not been well characterized. Also, it remains unknown how the recently introduced "Moses technology" may alter stone disintegration products. Three complementary analytical techniques have been used in this study to offer an in-depth characterization of disintegration products after in vitro Holmium laser lithotripsy: stereoscopic microscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy. Dust was separated from fragments based on its floating ability in saline irrigation. Depending on initial crystalline constituents, stone dust either conserved attributes found in larger RFs or showed changes in crystalline organization. These included conversion of calcium oxalate dihydrate towards calcium oxalate monohydrate, changes in carbapatite spectra towards an amorphous phase, changes of magnesium ammonium phosphate towards a differing amorphous and crystalline phase and the appearance of hydroxyapatite on brushite fragments. Comparatively, "Moses technology" produced more pronounced changes. These findings provide new insights suggesting a photothermal effect occurring in Holmium laser lithotripsy. Figure: Appearance of hydroxyapatite hexagons on stone dust collected after Holmium laser lithotripsy of a brushite stone using "Moses technology."

Shockwave Intravascular Lithotripsy for Calcified Coronary Lesions: First Real-World Experience

BACKGROUND

Calcified coronary lesions often cause suboptimal stent expansion, which is one of the greatest predictors of adverse outcomes such as stent thrombosis and restenosis. Shockwave intravascular lithotripsy (S-IVL; Shockwave Medical, Inc) is a recently approved technique used in the treatment of heavily calcified coronary lesions. We present our early real-world experience with the S-IVL device.

METHODS

All patients treated with S-IVL between October 2018 and January 2019 during their percutaneous coronary intervention (PCI) at our center were included.

RESULTS

During this period, a total of 26 patients undergoing PCI were treated with S-IVL prior to stent deployment (69% male; age, 72 ± 8 years). Indications for PCI were acute coronary syndromes (ACS) in 14 patients (54%), stable angina in 11 patients (42%), and PCI before transcatheter aortic valve implantation in 1 patient (4%). Seventy-one percent of the ACS cases undergoing PCI with S-IVL were to the perceived ACS culprit lesion during the index procedure, while 29% were staged PCIs to severe non-culprit lesions. Upfront S-IVL usage occurred in 58% of cases; the rest were bail-out procedures due to suboptimal initial balloon predilation. S-IVL was used most commonly in the left anterior descending coronary artery (50%), with 1.3 ± 0.5 stents implanted/target vessel. Angiographic success (<20% residual stenosis) occurred in all cases, with no procedural complications.

CONCLUSION

S-IVL appears to be a useful modality in coronary calcium modification to optimize stent expansion. This device obviates the need for more complex lesion preparation strategies such as rotational atherectomy, except in severe undilatable cases where S-IVL is impossible. Further study is warranted to compare different calcium modification devices with conventional balloon angioplasty.

Novel peroral direct digital cholangioscopy-assisted lithotripsy using a monorail technique through the overtube in patients with surgically altered anatomy (with video)

Efficacy of cholangioscopy-assisted lithotripsy for difficult stones such as huge stones, multiple large stones and an impacted stone in patients with non-altered anatomy has been reported. Herein, we describe peroral direct digital cholangioscopy (PDCS)-assisted electrohydraulic lithotripsy (EHL) with a new technique in patients with surgically altered anatomy. Five patients received PDCS-assisted EHL with the monorail technique due to failed conventional stone extraction. Balloon enteroscope was removed, leaving the stiff guidewire in the bile duct and an overtube with inflated balloons. The cholangioscope was then inserted into the bile duct over the wire through the overtube. After direct visualization of the stone, PDCS-assisted EHL was carried out. This technique was named the 'monorail technique'. Complete removal of biliary stones in one session was accomplished in four patients and only one case required two sessions. There was no adverse event in any of the cases. PDCS-assisted EHL using the monorail technique was effective and safe for difficult biliary stones in patients with surgically altered anatomy.

Thulium fiber laser ablation of kidney stones using an automated, vibrating fiber

Our preliminary study investigates an automated, vibrating fiber optic tip for dusting of kidney stones during thulium fiber laser (TFL) lithotripsy. A (0.75-mm diameter and 5-mm length) magnetic bead was attached to the fiber jacket, centered 2 cm from distal fiber tip. A solenoid was placed parallel to the fiber with a 0.5-mm gap between solenoid and magnetic bead on fiber. The solenoid was used to create a magnetic force on the bead, inducing fiber vibration. Calibration tests for fiber motion in both air and water were performed. The ablation crater characteristics (surface area, volume, depth, and major/minor axis) of uric acid stones were measured using optical coherence tomography, after delivery of 1500 TFL pulses at 1908 nm, 33 mJ, 500  μs, and up to 300 Hz, through 50-, 100-, and 150-μm-core fibers. The resonant frequency was dependent on fiber diameter and rigidity, with a cutoff pivot point for optimum vibration amplitude at 4 cm. Maximum fiber displacement is about 1 mm in water and 4 mm in air. For 50-, 100-, and 150-μm-core fibers, ablated surface area averaged 1.7, 1.7, and 2.8 times greater with vibrating fiber than fixed fiber, respectively. For these fibers, ablation volume averaged 1.1, 1.5, and 1.1 times greater with vibrating fiber than fixed fiber, given a fixed energy per pulse, respectively. Our preliminary study demonstrates the functionality of an automated, vibrating fiber system for stone "dusting," with significantly larger surface area but similar ablation volumes as a fixed fiber. Future studies will focus on optimization of fiber parameters (especially displacement) and miniaturization of system components to facilitate integration into ureteroscopes.

Routine Preoperative Electrocardiograms in Patients at Low Risk for Cardiac Complications During Shockwave Lithotripsy: Are They Useful?

INTRODUCTION

Routine preoperative electrocardiogram (ECG) before shockwave lithotripsy (SWL) is frequently performed despite recommendations against its use in asymptomatic patients undergoing low-risk surgical procedures. This study assesses whether routine preoperative ECG before SWL is useful in patients at low risk for cardiac complications.

MATERIALS AND METHODS

A retrospective study of SWL at our center (2003-2013) reviewed all cardiac-related preoperative cancellations, intraoperative complications, postoperative admissions, and emergency department presentations in patients at low risk for cardiac complications. Patients received SWL with sedation and continuous five-lead ECG monitoring.

RESULTS

Of 30,892 referrals, preoperative ECG triggered 13 (0.04%) cancelations in low-risk patients (1 with new atrial fibrillation and 12 with ischemia/previous infarction). Of these patients, 1 had a subsequent abnormal cardiac work-up and 11 underwent uncomplicated SWL without cardiac intervention (2 had unknown history). Of 27,722 treatments, 5 (0.02%) were stopped prematurely in low-risk patients because of arrhythmia (3 had normal preoperative ECG, 1 had abnormal ECG, and 1 did not complete ECG). Three patients developed an arrhythmia with sedation and 2 patients were admitted postoperatively because of cardiac complications (1 for atrial fibrillation and 1 for hypertension), of whom all had normal preoperative ECG. No patients presented to our emergency department with cardiac complications after SWL.

CONCLUSIONS

In patients at low risk for cardiac complications, preoperative ECG triggered very few cancellations and did not predict early termination of treatment or cardiac complications after SWL. These findings suggest that in low-risk patients, routine preoperative ECG has little effect on treatment or complication rate and should be omitted.

Endoscopic papillary large balloon dilation and endoscopic papillary balloon dilation both without sphincterotomy for removal of large bile duct stones: A propensity-matched analysis

BACKGROUND AND AIM

Endoscopic papillary large balloon dilation (EPLBD) without endoscopic sphincterotomy (EST) may facilitate extraction of large bile duct stones through achieving adequate dilation of the ampulla. However, contrary to favorable long-term outcomes after endoscopic papillary balloon dilation (EPBD), that of EPLBD without EST has been little investigated. Therefore, we conducted the current study to evaluate short- and long-term outcomes of EPLBD without EST and EPBD after removal of large bile duct stones (LBDS; ≥10 mm).

METHODS

This retrospective study included patients without a previous history of EST, EPBD or EPLBD who underwent EPLBD without EST or EPBD for removal of LBDS. Each patient in the EPLBD without EST group was matched to a patient in the EPBD group using propensity scores.

RESULTS

Forty-four patients in each group were matched for the analysis. Baseline characteristics were balanced after propensity matching. Rate of complete stone removal in a single session was higher (80% vs 16%, P < 0.001), number of ERCP sessions (1.3 ± 0.7 vs 2.4 ± 1.5, P < 0.001) and rate of lithotripsy use (30% vs 80%, P < 0.001) were smaller in the matched EPLBD without EST group. Contrary to null between-group differences in early adverse events (P = 0.99), a cumulative rate of late biliary complications was higher in the EPLBD without EST group (P = 0.02).

CONCLUSION

EPLBD without EST showed higher efficacy for removal of LBDS but was associated with worse long-term outcomes when compared to EPBD.

Efficacy and safety of laparoscopic holmium laser lithotripsy in the treatment of complicated biliary calculus: A PRISMA-compliant systematic reviews and meta-analysis

BACKGROUD

The aim of this study was to assess the efficacy and safety of laparoscopic holmium laser lithotripsy (LHLL) in the treatment of complicated biliary calculus.

METHODS

We systematically searched the electronic database (PubMed, EMBASE, Cochrane library, Web of science, and Chinese Biomedical Literature Database) up to May 2018 to identify case-controlled studies that compared LHLL with laparoscopic bile duct exploration (LBDE) for complicated biliary calculus.

RESULTS

Five case-controlled studies were included, with 541 patients (273 in the LHLL group and 268 in the LBDE group). Compared with LBDE, LHLL was associated with shorter operative time (weighted mean difference [WMD] = -40.04, P < .001) and lower estimated blood loss (EBL) (WMD = -56.42, P < .001), lesser duration of hospitalization (WMD = -3.93, P < .001) and lower rate of residual stone (OR = 0.13, P < .001). There was no statistically significant differences in bile leakage (OR = 0.48, P = .23) and hemobilia (OR = 0.49, 0.41).

CONCLUSION

Current evidence suggests that the efficacy of LHLL is superior to that of LBDE but they are similarly safe for the treatment of complicated biliary calculus. Limited by the quantity and quality of the studies included, these conclusions need to be verified by more high-quality studies.

Inducing Different Brain Injury Levels Using Shock Wave Lithotripsy

OBJECTIVES

To assess the feasibility of inducing different severities of shock wave (SW)-induced traumatic brain injury (TBI) using lithotripsy.

METHODS

Wistar rats (n = 36) were divided into 2 groups: group 1 (n = 20) received 5 SW pulses, and group 2 (n = 16) received 15 SWs pulses. The SW pulses were delivered to the right side of the frontal cortex. Neurologic and behavioral assessments (Garcia test, beam walking, rotarod, and elevated plus maze) were performed at the baseline and at 3, 6, 24, 72, and 168 hours after injury. At day 7 after injury (168 hours), we performed cerebral angiography to assess the presence of cerebral vasospasm and vascular damage due to SW-induced TBI. At the conclusion of the study, the animals were euthanized to assess damage to brain tissue using an overall histologic severity score.

RESULTS

The Garcia score was significantly higher, and the anxiety index (based on the elevated plus maze) was significantly lower in group 1 compared to group 2 (P < .05). The anxiety index for group 1 returned to the baseline level in a fast nonlinear fashion, whereas the anxiety index for group 2 followed a distinct slow linear reduction. Cerebral angiograms revealed a more severe vasospasm for the animals in group 2 compared to group 1 (P = .027). We observed a statistically significant difference in the overall histologic severity scores between the groups. The median (interquartile range) overall histologic severity scores for groups 1 and 2 were 3.0 (2.75) and 6.5 (6.0), respectively (P = .023).

CONCLUSIONS

We have successfully established different SW-induced TBI severities in our SW-induced TBI model by delivering different numbers of SW pulses to brain tissue.