Front Surg. 2017; 4: 57.

Holmium Laser Lithotripsy in the New Stone Age: Dust or Bust?


Ali H. Aldoukhi,1,* William W. Roberts,1,2 Timothy L. Hall,2 and Khurshid R. Ghani1

Abstract
Modern day holmium laser systems for ureteroscopy (URS) provide users with a range of settings, namely pulse energy (PE), pulse frequency (Fr), and pulse width (PW). These variables allow the surgeon to choose different combinations that have specific effects on stone fragmentation during URS lithotripsy. Contact laser lithotripsy can be performed using fragmentation or dusting settings. Fragmentation employs settings of low Fr and high PE to break stones that are then extracted with retrieval devices. Dusting is the utilization of high Fr and low PE settings to break stones into submillimeter fragments for spontaneous passage without the need for basket retrieval. Use of the long PW mode during lithotripsy can reduce stone retropulsion and is increasingly available in new generation lasers. During non-contact laser lithotripsy, stone fragments are rapidly pulverized in a calyx in laser bursts that result in stones breaking into fine fragments. In this review, we discuss the effect of different holmium laser settings on stone fragmentation, and the clinical implications in a very much evolving field.

Keywords: ureteroscopy, lithotripsy, holmium laser, dusting, fragmentation

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J Urol. 2018 Feb;199(2):487-494. doi: 10.1016/j.juro.2017.09.069. Epub 2017 Sep 18.
Accurately Diagnosing Uric Acid Stones from Conventional Computerized Tomography Imaging: Development and Preliminary Assessment of a Pixel Mapping Software.


Ganesan V1, De S2, Shkumat N3, Marchini G4, Monga M5.

Abstract
PURPOSE:
Preoperative determination of uric acid stones from computerized tomography imaging would be of tremendous clinical use. We sought to design a software algorithm that could apply data from noncontrast computerized tomography to predict the presence of uric acid stones.

MATERIALS AND METHODS:
Patients with pure uric acid and calcium oxalate stones were identified from our stone registry. Only stones greater than 4 mm which were clearly traceable from initial computerized tomography to final composition were included in analysis. A semiautomated computer algorithm was used to process image data. Average and maximum HU, eccentricity (deviation from a circle) and kurtosis (peakedness vs flatness) were automatically generated. These parameters were examined in several mathematical models to predict the presence of uric acid stones.

RESULTS:
A total of 100 patients, of whom 52 had calcium oxalate and 48 had uric acid stones, were included in the final analysis. Uric acid stones were significantly larger (12.2 vs 9.0 mm, p = 0.03) but calcium oxalate stones had higher mean attenuation (457 vs 315 HU, p = 0.001) and maximum attenuation (918 vs 553 HU, p <0.001). Kurtosis was significantly higher in each axis for calcium oxalate stones (each p <0.001). A composite algorithm using attenuation distribution pattern, average attenuation and stone size had overall 89% sensitivity, 91% specificity, 91% positive predictive value and 89% negative predictive value to predict uric acid stones.

CONCLUSIONS:
A combination of stone size, attenuation intensity and attenuation pattern from conventional computerized tomography can distinguish uric acid stones from calcium oxalate stones with high sensitivity and specificity.

Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

KEYWORDS:
calcium oxalate; diagnostic imaging; nephrolithiasis; tomography; uric acid; x-ray computed

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BJU Int. 2017 Nov;120(5):702-709. doi: 10.1111/bju.13848. Epub 2017 Apr 17.
Surgical outcomes of percutaneous nephrolithotomy in 3402 patients and results of stone analysis in 1559 patients.


Rizvi SAH1, Hussain M1, Askari SH1, Hashmi A1, Lal M1, Zafar MN2.

Abstract
OBJECTIVE:
To report our experience of a series of percutaneous nephrolithotomy (PCNL) procedures in a single centre over 18 years in terms of patient and stone characteristics, indications, stone clearance and complications, along with the results of chemical analysis of stones in a subgroup.

PATIENTS AND METHODS:
We retrospectively analysed the outcomes of PCNL in 3402 patients, who underwent the procedure between 1997 and 2014, obtained from a prospectively maintained database. Data analysis included patients’ age and sex, laboratory investigations, imaging, punctured calyx, duration of operation, volume of irrigation fluid, radiation exposure time, blood transfusion, complications and stone-free status at 1-month follow-up. For the present analysis, outcomes in relation to complications and success were divided in two eras, 1997-2005 and 2006-2014, to study the differences.

RESULTS:
Of the 3402 patients, 2501 (73.5%) were male and 901 (26.5%) were female, giving a male:female ratio of 2.8:1. Staghorn (partial or complete) calculi were found in 27.5% of patients, while 72.5% had non-staghorn calculi. Intracorporeal energy sources used for stone fragmentation included ultrasonography in 917 patients (26.9%), pneumatic lithoclast in 1820 (53.5%), holmium laser in 141 (4.1%) and Lithoclast® master in 524 (15.4%). In the majority of patients (97.4%) a 18-22-F nephrostomy tube was placed after the procedure, while 69 patients (2.03%) underwent tubeless PCNL. The volume of the irrigation fluid used ranged from 7 to 37 L, with a mean of 28.4 L. The stone-free rate after PCNL in the first era studied was 78%, vs 83.2% in the second era, as assessed by combination of ultrasonography and plain abdominal film of the kidney, ureter and bladder. The complication rate in the first era was 21.3% as compared with 10.3% in the second era, and this difference was statistically significant. Stone analysis showed pure stones in 41% and mixed stones in 58% of patients. The majority of stones consisted of calcium oxalate.

CONCLUSIONS:
This is the largest series of PCNL reported from any single centre in Pakistan, where there is a high prevalence of stone disease associated with infective and obstructive complications, including renal failure. PCNL as a treatment method offers an economic and effective option in the management of renal stone disease with acceptable stone clearance rates in a resource-constrained healthcare system.

© 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

KEYWORDS: #KidneyStones; #UroStone; PCNL; renal stones; staghorn stones

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BJU Int. 2017 Jun;119(6):913-918. doi: 10.1111/bju.13817. Epub 2017 Mar 21.

Percutaneous nephrolithotomy access by urologist or interventional radiologist: practice and outcomes in the UK.


Armitage JN1, Withington J2, Fowler S3, Finch WJG4, Burgess NA4, Irving SO4, Glass J5, Wiseman OJ1; BAUS section of Endourology.

Abstract
OBJECTIVE:
To compare outcomes of urologist vs interventional radiologist (IR) access during percutaneous nephrolithotomy (PCNL) in the contemporary UK setting.

PATIENTS AND METHODS:
Data submitted to the British Association of Urological Surgeons PCNL data registry between 2009 and 2015 were analysed according to whether access was obtained by a urologist or an IR. We compared access success, number and type of tracts, and perceived and actual difficulty of access. Postoperative outcomes, including stone-free rates, lengths of hospital stay and complications, including transfusion rates, were also compared.

RESULTS:
Overall, percutaneous renal access was undertaken by an IR in 3453 of 5211 procedures (66.3%); this rate appeared stable over the entire study period for all categories of stone complexity and in cases where there was predicted or actual difficulty with access. Only 1% of procedures were abandoned because of failed access and this rate was identical in each group. IRs performed more multiple tract access procedures than urologists (6.8 vs 5.1%; P = 0.02), but had similar rates of supracostal punctures (8.2 vs 9.2%; P = 0.23). IRs used ultrasonograhpy more commonly than urologists to guide access (56.6% vs 21.7%, P < 0.001). There were no significant differences in complication rates, lengths of hospital stay or stone-free rates.

CONCLUSIONS:
Our findings suggest that favourable PCNL outcomes may be expected where access is obtained by either a urologist or an IR, assuming that they have received the appropriate training and that they are skilled and proficient in the procedure.

© 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

KEYWORDS: access; interventional radiologist; outcomes; percutaneous nephrolithotomy; urologist

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J Endourol. 2017 Jun;31(6):598-604. doi: 10.1089/end.2017.0050. Epub 2017 Apr 25.

Use of the Moses Technology to Improve Holmium Laser Lithotripsy Outcomes: A Preclinical Study.


Elhilali MM1, Badaan S2, Ibrahim A1,3, Andonian S1.

Abstract
OBJECTIVE:
To evaluate in vitro and in vivo effects of Moses technology in Holmium laser and to compare it with the Regular mode in terms of lithotripsy efficiency and laser-tissue interactions.

METHODS:
The Lumenis® Pulse™ P120H holmium laser system together with Moses D/F/L fibers were used to compare the Regular mode with the Moses modes in stone retropulsion by using a high-speed camera, and stone ablation efficiency. In addition, a porcine ureteroscopy model was used to assess stone fragmentation and dusting as well as laser-tissue interaction with the ureteral wall.

RESULTS:
After a laser pulse, in vitro stone displacement experiments showed a significant reduction in retropulsion when using the Moses mode. The stone movement was reduced by 50 times at 0.8 J and 10 Hz (p < 0.01). The pronounced reduction of retropulsion in the Moses mode was clearly observed during fragmentation setting (high energy) and dusting (low energy, high Hz). In addition, stone fragmentation tests showed that the Moses modes resulted in a significantly higher ablation volume when compared with the Regular mode (160% higher; p < 0.001). In vivo assessment also supported the reduction in retropulsion when treating stones in the porcine kidney. Histological analysis of the porcine ureter after direct lasing in the Moses mode suggested less damage than in the Regular mode.

CONCLUSIONS:
The Moses technology resulted in more efficient laser lithotripsy, in addition to significantly reduced stone retropulsion, and displayed a margin of safety that may result in a shorter procedural time and safer lithotripsy.

KEYWORDS: Holmium-YAG laser; laser lithotripsy; preclinical evaluation; prospective study

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J Endourol. 2017 Apr;31(4):334-340. doi: 10.1089/end.2016.0851. Epub 2017 Mar 22.

Safety, Feasibility, and Efficacy of Bilateral Synchronous Percutaneous Nephrolithotomy for Bilateral Stone Disease: Evidence from a Systematic Review.


Jones P1, Dhliwayo B1, Rai BP2, Mokete M1, Amitharaj R3, Aboumarzouk OM4, Somani BK5.

Abstract
INTRODUCTION:

With the evolution of endourologic technology, bilateral synchronous percutaneous nephrolithotomy (BS-PCNL) has emerged as a potentially practical intervention for patients with bilateral lithiasis. Although tradition has favored a staged approach, an increasing number of original studies have reported their experiences with the synchronous approach.

MATERIALS AND METHODS:
A Cochrane style search was performed after development of a sensitive and predefined search strategy. Primary outcomes measured were initial and final stone-free rate (SFR), drop in hemoglobin, hospital stay, operative time, and complication rates. Additional information was collected on (but not limited to) baseline characteristics, stone complexity, number of tracts made, success rate, and transfusion rate.

RESULTS:
From a total 187 studies, 11 were identified (published between 1997 and 2015), and they were included in this review. In total, 594 patients with a mean age of 46 years and a male:female ratio of 3:1 underwent BS-PCNL procedures, the majority of which was under the prone position. In 87.1% (range: 71.4%-100%) of cases, the synchronous approach was performed as planned. Multiple access tracts were established in an average of 16.7% (4.1%-24%) renal units. Mean initial SFR and final SFR were 72.6% (49%-85%) and 92.4% (87%-96.9%), respectively, with a mean operative time of 171.1 minutes (range: 107.4-269 minutes). Mean hospital stay was 3.9 days (range: 1.25-15 days). Mean complication rate per study was 23.4% (range: 12.1%-54% per study). The majority were Clavien Grade 1 (60.9%), of which fever resolving spontaneously was the most common complication. No deaths were reported in any of the papers.

CONCLUSION:

BS-PCNL seems to be a good endourologic approach for patients with bilateral stone disease, which can render high SFRs and maintain a noninferior safety profile compared with the staged approach. This technique demands careful patient selection, counseling and should be preferably performed in endourology centers with large case volumes.

KEYWORDS: endourology; percutaneous nephrolithotomy; urolithiasis

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World J Urol. 2017 Nov;35(11):1651-1658. doi: 10.1007/s00345-017-2055-z. Epub 2017 Jun 7.

Trends of ‘urolithiasis: interventions, simulation, and laser technology’ over the last 16 years (2000-2015) as published in the literature (PubMed): a systematic review from European section of Uro-technology (ESUT).

Pietropaolo A1, Proietti S2, Geraghty R1, Skolarikos A3,4,5, Papatsoris A3,4,5, Liatsikos E4,5,6, Somani BK7,8.

Abstract
PURPOSE:
To look at the bibliometric publication trends on ‘Urolithiasis’ and aspects of treatment and training associated with it over a period of 16 years from 2000 to 2015. To this end, we conducted this study to look at the publication trends associated with urolithiasis, including the use of simulation, laser technology, and all types of interventions for it.

MATERIALS AND METHODS:
We performed a systematic review of the literature using PubMed over the last 16 years, from January 2000 to December 2015 for all published papers on ‘Urolithiasis’. While there were no language restrictions, English language articles and all non-English language papers with published English abstracts were also included. Case reports, animal and laboratory studies, and those studies that did not have a published abstract were excluded from our analysis. We also analyzed the data in two time periods, period-1 (2000-2007) and period-2 (2008-2015).

RESULTS:
During the last 16 years, a total of 5343 papers were published on ‘Urolithiasis’, including 4787 in English language and 556 in non-English language. This included papers on URS (n = 1200), PCNL (n = 1715), SWL (n = 887), open stone surgery (n = 87), laparoscopic stone surgery (n = 209), pyelolithotomy (n = 35), simulation in Endourology (n = 82), and use of laser for stone surgery (n = 406). When comparing the two time periods, during period 2, the change was +171% (p = 0.007), +279% (p < 0.001), and -17% (p = 0.2) for URS, PCNL, and SWL, respectively. While there was a rise in laparoscopic surgery (+116%), it decreased for open stone surgery (-11%) and pyelolithotomy (-47%). A total of 82 papers have been published on simulation for stone surgery including 48 papers for URS (67% rise in period-2, p = 0.007), and 34 papers for PCNL (480% rise in period-2, p < 0.001). A rising trend for the use of laser was also seen in period 2 (increase of 126%, p < 0.02, from 124 papers to 281 papers).

CONCLUSIONS:
Published papers on intervention for Urolithiasis have risen over the last 16 years. While there has been a steep rise of URS and minimally invasive PCNL techniques, SWL and open surgery have shown a slight decline over this period. A similar increase has also been seen for the use of simulation and lasers in Endourology.

KEYWORDS: Laser; Publication; Simulation; Stone; Trends; Ureteroscopy; Urolithiasis

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World J Urol. 2017 Nov;35(11):1765-1770. doi: 10.1007/s00345-017-2053-1. Epub 2017 May 30.

Impact of laser fiber tip cleavage on power output for ureteroscopy and stone treatment.


Haddad M1,2,3, Emiliani E2,4, Rouchausse Y3, Coste F3, Berthe L3, Doizi S1,2, Buttice S2,5, Somani B1,2, Traxer O6,7.

Abstract
PURPOSE:

Holmium:YAG laser is the most used laser for urolithiasis. Generally, we use metallic scissors to cut the fiber tip to restore its effectiveness. Many cleaving methods have been described to avoid fiber damage and to restore its greatest power to the fiber. There is a lack of information regarding which cleaving method should be used and its effect on the fiber. In order to compare these effects, we studied different cleavage methods in terms of power output and its effects on the fiber.

METHODS:
New single-use 272-μm fibers were used with a holmium:YAG laser lithotripter. Five kinds of fiber tips were compared: a new intact fiber, cleaved with ceramic scissors, cleaved with metallic scissors, first cleaved then stripped and first stripped then cleaved. The fibers were used against synthetic stones (BegoStone®) similar to calcium oxalate monohydrate, with fragmentation (SP, 5 Hz, 1.5 J) and dusting (LP, 15 Hz, 0.5 J) settings. We measured power output at 0, 1, 5, 10 and 15 min.

RESULTS:
For fragmentation parameters, there was a statistical difference between the 5 groups at 0 and 1 min of laser use (p < 0.05) and none for time period over 1 min (p = 0.077-0.658). For dusting parameters, there was a statistical difference between the 5 groups at 0 min of laser use (p < 0.05) and none for time period over 0 min (p = 0.064-1).

CONCLUSION:
Cleaving the fiber tip may restore its effectiveness to the fiber, but only for a limited time, although it may preserve the scopes from damage.

KEYWORDS: Cleavage tool; Endourology; Fiber; Laser; Stone; Ureteroscopy

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J Endourol Case Rep. 2017; 3(1): 84–86.

Troubleshooting for Ureteroscopy Complicated by Unexpected Guidewire Looping and Entrapment

Ioannis Efthimiou, MD, MSc, FEBU,corresponding author Zacharias Chousianitis, MD, and Kostadinos Skrepetis, MD, PhD, FEBU
Abstract
This report presents a bizarre and unusual case of looping and entrapment of a hydrophilic guidewire in the ureter of a 65-year-old woman with a stone in the lower ureter at the time of ureteroscopy and laser lithotripsy. We describe endourology maneuvers to remove the retained guidewire. Looping and entrapment of guidewire is a rare complication that urologists may face when they do not follow the basic principles of guidewire insertion. In that case, successful resolution is based both on surgeon’s inspiration to apply the appropriate endourology maneuvers and availability of a variety of endourology tools in the theater. Both may lead urologists to avoid more invasive and morbid approaches for their patients.

Keywords: guidewire, complication, endourology

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