Ablation Speed Research Articles

A triplexer chip with cascaded butterfly multimode interference couplers by femtosecond laser microprocessing

A triplexer chip utilizing three cascaded butterfly multimode interference (MMI) couplers to output three optical signals from their respective ports is proposed. The chip consists of a borosilicate glass substrate, a JA photoresist core layer, and an RZJ photoresist cladding. The beam propagation method (BPM) is used to design and optimize the chip. The femtosecond laser processing is investigated, and the chip is processed with a laser power of 1.6 mW and an ablation speed of 4 mm/s. Tests show that the chip meets the design specifications with a low insertion loss of 4.34 dB, an extinction ratio of more than 15 dB, a crosstalk of less than −15 dB, and a 3 dB bandwidth up to 76.8 nm.

Assessment of Holmium:YAG, Pulsed-Thulium:YAG and Thulium Fiber Lasers for Urinary Stone Ablation. In Vitro Study.

Objective: To evaluate the ablation speed (AS), laser efficiency and direct thermal lesions during urinary stone lithotripsy with the current available laser technologies: Holmium:YAG (Ho:YAG), pulsed-Thulium:YAG (p-Tm:YAG) and thulium fiber laser (TFL) in vitro using different laser settings. Materials and Methods: Ho:YAG, p-Tm:YAG, and TFL laser system were used in an in vitro ureteral model with a volume of 125 mm3 Begostone. The following parameters were tested across all laser devices: 0.6J/10 Hz (6 W), 0.6 J/20 Hz (12 W), 1.5 J/10 Hz (15 W), and 1.5 J/20 Hz (30 W), employing short pulse width for all lasers and long pulse width for Ho:YAG and p-Tm:YAG. Ten participants conducted the experimental setup during 3-minutes laser on time, combining the laser technology, settings, and pulse widths, with a total of 20 different combinations. The efficiency, AS and ureteral damage resulting from each intervention were analyzed. Results: p-Tm:YAG and TFL demonstrated significantly higher efficiency compared with Ho:YAG (0.049 ± 0.02 Δgr/KJ and 0.042 ± 0.01 Δgr/KJ vs 0.029 ± 0.01 Δgr/KJ; p < 0.05). In all laser sources, as the power increases, the AS also increases (p < 0.05). Furthermore, only at high-energy settings (1.5 J) higher frequency led to increase AS (p < 0.05). Both, p-Tm:YAG and TFL exhibited higher AS compared to Ho:YAG (0.64 ± 0.33 Δgr/s and 0.62 ± 0.31 Δgr/s vs 0.44 ± 0.22 Δgr/s; p < 0.05). Regarding ureteral injuries, as the power increases, there is a higher chance of ureteral damage (p = 0.031). No differences were observed between laser technologies (p = 0.828). Conclusions: Both, p-Tm:YAG and TFL exhibited superior performances during laser lithotripsy compared with Ho:YAG, as they demonstrated higher efficiency and ablation speed. Thermal damage did not appear to be associated with specific laser equipment, but higher grades of lesions are described by increasing power.

Comparison of Moses laser and Raykeen laser in patients with impacted upper ureteral stone undergoing flexible ureteroscopic holmium laser lithotripsy

BackgroundTo compare the operative effect and clinical efficacy of the Moses laser mode and the Raykeen holmium laser energy platform powder mode under flexible ureteroscopic lithotripsy in patients with impacted upper ureteral stones.MethodsFrom March 2022 to September 2022, 72 patients were divided into a Moses laser group and a Raykeen laser group according to surgical method, with 36 patients in each group. CT and ureteroscopy confirmed that all patients had isolated impacted upper ureteral stones. The stone volume (mm3), stone density (Hu) and severity of hydronephrosis were measured by CT. Postoperative complications were evaluated using the Clavien–Dindo score.ResultsThere were no complications of ureteral stenosis related to the laser treatment. The operative time and lithotripsy time were lower in the Moses laser group than in the Raykeen laser group (P < 0.05). The stone-free survival rate did not differ significantly between the two groups (P = 0.722). Stone volume was found to be positively correlated with laser energy and lithotripsy time in both groups (P < 0.01). There was no significant correlation between laser energy and lithotripsy time or ureteral stone density (Hu) in the Moses laser group (P > 0.05) or the Raykeen laser group (P > 0.05).ConclusionsThe contact mode of Moses technology and the powder mode of Raykeen laser lithotripsy can be used for the ablation of a single impacted upper ureteral stone. The ablation speed was related to the stone volume and the severity of polyp hyperplasia, not the stone density. We recommend the use of the powdered mode as a therapeutic measure for the treatment of impacted upper ureteral stones in flexible ureteroscopic lithotripsy.

Microstructuring of fused silica by laser-induced microplasma using a pyrographite target for phase optical elements fabrication

In this paper, we purpose to use laser-induced microplasma occurred from a pyrographite target by laser ablation for microstruturing of fused silica plate to fabricate phase optical elements. Laser parameters for erosive plasma torch formation and subsequent etching of fused silica were determined based on preliminary experimental studies and estimated energy calculations. The influence of the overlap coefficients in the focal spot on the reproducibility of etching depths results and the deviation accuracy of etching depths with the found laser parameters was experimentally studied. The best results in terms of accuracy (no more than 0.1 μm) in deviations of etching depths are achieved with the overlap coefficient of 0.5. Moreover, the paper presents estimated calculations of the speed and efficiency of ablation, as well as the coefficient of energy conversion from laser radiation to the ablation energy of fused silica, which was ∼ 0.25. Based on achieved results an attempt was made to fabricate the 6-sector SPP for the wavelength of 355 nm.

Successful treatment of staghorn stones with flexible ureteroscopy and thulium fiber laser (TFL) lithotripsy: initial experience with 32 cases

PurposeTo investigate the efficacy and safety of flexible ureteroscopy with thulium fiber laser lithotripsy for management of renal staghorn stones.Materials and MethodsThirty-two patients with staghorn stones were recruited. Stone characteristics including: width, length, volume and density were analyzed. Ablation speed, laser efficacy and laser activity were recorded. The primary outcome was to assess stone free rate after the procedure using spiral CT scan.ResultsThe median stone volume was 7339 (3183–53838) mm3. Median operative and lasing time were 135 (70–200) and 117 (50–180) minutes, respectively. The mean total energy delivered was 63.9 ± 30 KJ with a median ablation speed of 1.3 (0.5–4.9) mm3/sec. Mean laser efficacy was 7.5 ± 3.6 Joules/mm3. A total of 12 complications occurred in 8 patients (25%). The median hospital stay was 7 (3.5–48) hours and 30 patients (93.7%) were discharged on the same day of surgery. After the first session, seventeen patients (53%) were stone free with no residual fragments while six (19%) patients had residuals £ 2 mm. Nine patients (28%) had residuals > 2 mm with median residual size of 4 (3–9) mm. A second intervention was required in 4 cases.The overall stone free rate after completion of treatment was 65.6%.ConclusionFlexible ureteroscopy with thulium fiber laser lithotripsy is a safe and effective treatment option for staghorn stones with stone free rate comparable to standard PCNL with advantages of minimal morbidity, minimal blood loss and shorter hospital stay.

Optical properties of the O3+-ion implanted and femtosecond-laser ablated ridge waveguide in the Er3+-doped germanate glass

Er3+-doped germanate glass is a kind of polyfunctional material for optical and photonic applications. The work reports on the preparation and properties of O3+-ion implanted and femtosecond-laser ablated Er3+-doped germanate glass optical ridge waveguide. The energy is 6.0 MeV and the fluence is 5 × 1014 ions cm−2 for the O3+-ion implantation. The pulse energy and the scanning speed of the femtosecond-laser ablation are 3 μJ and 50 μm s−1, respectively. The SRIM 2013 is used to calculate the vacancy profile induced by the implantation in the Er3+-doped germanate glass for the physical mechanisms of the waveguide formation. The optical microscopy images of the cross-section of the waveguide are captured by the Nikon microscope. The light-guiding properties of the ion-implanted and laser-ablated waveguides are studied by the end-face coupling system. The ridge waveguide has been produced by combining the FS ablation with ion implantation technologies for the first time in the Er3+-doped germanate glass. The propagation of light field indicates that it has the potential for photonics applications based on the planar and ridge Er3+-doped germanate glass waveguides.

A historical comparison of thulium fiber laser systems for stone lithotripsy: navigating toward safe and effective parameters.

Medical device companies have introduced new TFL machines, including Soltive (Olympus, Japan), Fiber Dust (Quanta System, Italy), and TFLDrive (Coloplast, France). The primary objective of this study is to compare our initial clinical experiences with TFL using those devices. Through this historical comparison of Thulium Fiber Laser systems for stone lithotripsy, we aim to advance our understanding and approach toward achieving safe and effective TFL parameters. The data for this comparative analysis were extracted from three distinct prospective series that were previously published, outlining our initial clinical experience with the Soltive (Olympus, Japan), FiberDust laser (Quanta System, Italy), and TFLDrive laser (Coloplast, France). Parameters such as stone size, stone density, laser-on time (LOT), and laser settings were meticulously recorded. Additionally, we assessed critical variables such as ablation speed (expressed in mm3/s) and Joules/mm3 for each lithotripsy procedure. A total of 149 patients were enrolled in this study. Among them, 120 patients were subjected to analysis concerning renal stones. Statistically significant differences were observed in the median (IQR) stone volume: 650 (127-6027) mm3 for TFLDrive, 1800 (682.8-2760) mm3 for Soltive, and 1125 (294-4000) mm3 for FiberDust (p: 0.007); while there were no differences regarding stone density among the groups. Significant variations were identified in median (IQR) pulse energy, frequency, and total power. The Soltive group exhibited lower energy levels (0.3J vs. 0.6J, p: 0.002) but significantly higher pulse frequency (100Hz vs. 17.5Hz, p: 0.003) and total power (24 W vs. 11W, p: 0.001) compared to the other groups. Laser-on time showed no substantial differences across all three groups. Additionally, a statistically significant difference was observed in median J/mm3, with the TFLDrive group using higher values (24J/mm3, p: 0.001), while the Soltive group demonstrated a higher median ablation speed of 1.16 mm3/s (p: 0.001). The overall complication rate remained low for all groups, with comparable stone-free rates. By reducing pulsed frequency, we improved laser efficiency, but smaller volumes lead to decreased efficiency due to increased retropulsion and fragment movement. Further studies are needed to identify and establish the appropriate laser settings for this new technology.

Mitigation of bio-corrosion characteristics of coronary artery stent by optimising fs-laser micromachining parameters

Cardiovascular diseases, particularly coronary artery disease, pose big challenges to human life. Deployment of the stent is a preferable treatment for the above-mentioned disease. However, stents are usually made up of shape memory alloy called Nitinol. The poorer surface finish on the machined nitinol stents accelerates the migration of Nickel ions from the implanted nitinol stent, which is considered toxic and can lead to stenosis. The current study deals with controlling surface quality by minimising surface roughness and improving corrosion resistance. Femtosecond laser (fs-laser 10−15 s) micromachining was employed to machine the Nitinol surface to achieve sub-micron surface roughness. The Grey relational analysis (GRA)-coupled design of the experimental technique was implemented to determine optimal levels of four micromachining parameters (laser power, pulse frequency, scanning speed, and scanning pattern) varied at three levels to achieve minimum surface roughness and to maximise the volume ablation. The results show that to yield minimum surface roughness and maximum volume ablation, laser power and scanning speed are in a higher range. In contrast, the pulse frequency is lower, and the scanning pattern is in a zig-zag manner. ANOVA results manifest that scanning speed is the predominant factor in minimising surface roughness, followed by pulse frequency. Furthermore, the corrosion behaviour of the machined nitinol specimens was evaluated, and the results show that specimens with lower surface roughness had lower corrosion rates.

Initial experience with the graphical user interface for laser parameters setting of a new thulium fibre laser source device for urinary pathologies treatment.

We aimed to evaluate the concordance between the pre-settings ranges of thulium fibre laser (TFL) (Coloplast TFL Drive, Denmark) with easy-to-use graphical user interface and the laser settings used by a high-volume endo-urologist during surgical procedures. In October 2022, we prospectively collected data of 67 patients who underwent TFL Drive (Coloplast, Denmark) for the management of urinary stones. Urothelial tumour (upper tract urinary cancer (UTUC) and bladder) 200 and 150μm laser fibres were used for procedures. Stones characteristics (size and density) tumours and stenosis localizations, laser-on time (LOT), and laser settings were recorded. We also assessed the ablation speed (mm3/s), laser power (W), and Joules/mm3 values for each lithotripsy. A total 67 patients took part in the study. Median age was 52 (15-81)years. 55 (82%), 8 (12%), and 4 (6%) patients presented urinary stones, urothelial tumour, and stenosis, respectively. Median stone volume was 438 (36-6027)mm3 and median density was 988 (376-2000) HU. Median pulse energy was 0.6 (0.3-1.2), 0.8 (0.5-1) and 1J for urinary stones, urothelial tumour and stenosis respectably. Endoscopically stone-free rate was 89%. Graphical user interface and surgeon accordance with the safety range were observed in 93.2%, 100% and 100% for urinary stones, UTUC and stenosis, respectively. During endoscopic procedures for urinary stones treatment, it is frequently needed to change laser parameters. These new TFL and GUI technology parameters remained in the pre-set security range in 94.1% of procedures.

Thulium Fiber Laser vs Pulse-Modulated Holmium MOSES Laser in Flexible Ureteroscopy for the Management of Kidney Stones: A Single-Center Retrospective Analysis.

Introduction and Objective: The study's primary objective was to compare the laser efficiency and clinical outcomes of two widely used systems, the holmium MOSES laser and the thulium fiber laser (TFL), in managing kidney stones. The secondary outcomes were to evaluate the impact of stone composition on laser efficacy. Methods: We conducted a retrospective review of patients who underwent flexible ureteroscopy (f-URS) for solitary renal calculi between December 2020 and August 2022 at our institution and had a 3-month postoperative CT scan. Patient demographics and stone parameters were recorded, including stone site, size, volume, and density. Intraoperative data were collected and analyzed, including total operative time, ureteroscopy time, lasing time, technique, total energy delivered, and stone composition. All patients underwent a CT scan at 3 months follow-up. We recorded the presence of residual stones and the percentage of stone volume reduction. Ablation efficiency was calculated by dividing the energy utilized (J) by the stone volume (mm3). The ablation speed was calculated by dividing the stone volume (mm3) by the lasing time (seconds). Patients with a stone size <4 mm were deemed stone-free. Results: The MOSES and TFL groups comprised 62 and 49 patients, respectively. There were no significant differences between groups for baseline patient demographics or stone characteristics. The two modalities had comparable total energy, laser time, efficacy, and ablation speeds. No differences were detected in stone-free rates or complications between both groups. When dealing with calcium phosphate stones, we observed that the lasing time was significantly shorter with MOSES than TFL (7.95 vs 10.85 minutes, respectively [p = 0.01]). Conclusions: MOSES and TFL laser systems had comparable efficacy for lithotripsy of renal calculi during f-URS; however, calcium phosphate stones had a longer lasing time with TFL. REB Number: 100210.

Ureteroscopic lithotripsy by thulium fiber laser versus holmium laser: A single-center prospective randomized study.

Laser lithotripsy has been the standard of care for lower and mid-ureteric calculi. Thulium fiber laser (TFL) is a new introduction to this field, which has been extensively studied for retrograde intrarenal surgery. We have done a prospective randomized study of ureteroscopic lithotripsy between TFL and holmium: Yttrium-aluminum-garnet (HO: YAG) laser to know the efficacy of stone fragmentation, stone-free rate, and complications. A prospective randomized study was done in our hospital from March 2021 to May 2022 on patients planned for ureteroscopic laser lithotripsy. Patients with distal and mid-ureteral stones from 4 mm to 15 mm were included. The laser was used to fragment the stone. All the stones were fragmented from the center to periphery. The setting used was up to 10 W (6-10 Hz, 1J) for TFL and up to 10 W for HO: YAG (5-10 Hz, 0.5-1J). Once the stones were fragmented, they were retrieved until complete visual clearance. Demographic data and stone parameters such as stone size, volume, density, laterality, laser usage time, total operative time, and total energy used were recorded. Operative time, lasering time, retropulsion rate, ablation speed, and visibility score were recorded. Each group had 90 randomized patients. Both the groups had similar kinds of patient and stone profiles. The mean operating time was 18.5 ± 1.5 min (95% confidence interval [CI] 16.2-25.6) in the TFL group, which was shorter than the holmium group 31.6 ± 1.2 min (95% CI 18.4-38.5), and it was statistically significant (P = 0.024,). Lasering time was also statistically significant with less lasering time with TFL group 7.4 ± 1.8 min (95% CI 5.2-10.3) versus holmium group 14.8 ± 1.5 min (95% CI 12.3-18.4) (P = 0.011). Laser efficacy and ablation speed were better in the TFL group compared to the HO: YAG group and were statistically significant. The visual score was better in HO: YAG group compared to the TFL group. TFL is more efficacious and faster than Holmium: Yag laser. Complications were similar between the groups. Stone-free rate was also similar between both the groups.

GHz bursts in MHz burst (BiBurst) enabling high-speed femtosecond laser ablation of silicon due to prevention of air ionization

For the practical use of femtosecond laser ablation, inputs of higher laser intensity are preferred to attain high-throughput material removal. However, the use of higher laser intensities for increasing ablation rates can have detrimental effects on ablation quality due to excess heat generation and air ionization. This paper employs ablation using BiBurst femtosecond laser pulses, which consist of multiple bursts (2 and 5 bursts) at a repetition rate of 64 MHz, each containing multiple intra-pulses (2–20 pulses) at an ultrafast repetition rate of 4.88 GHz, to overcome these conflicting conditions. Ablation of silicon substrates using the BiBurst mode with 5 burst pulses and 20 intra-pulses successfully prevents air breakdown at packet energies higher than the pulse energy inducing the air ionization by the conventional femtosecond laser pulse irradiation (single-pulse mode). As a result, ablation speed can be enhanced by a factor of 23 without deteriorating the ablation quality compared to that by the single-pulse mode ablation under the conditions where the air ionization is avoided.

MP23-12 CLINICAL EFFICIENCY OF THULIUM FIBER LASER FOR RIRS IN LARGE VOLUME STONES (15-25MM): A MULTICENTRIC EXPERIENCE

You have accessJournal of UrologyCME1 Apr 2023MP23-12 CLINICAL EFFICIENCY OF THULIUM FIBER LASER FOR RIRS IN LARGE VOLUME STONES (15-25MM): A MULTICENTRIC EXPERIENCE Abhishek Singh, Soundarya Ganesan, Rohan Batra, Abhijit Patil, Arvind Ganpule, Ravindra Sabnis, Mahesh Desai, and ChandraMohan Vaddi Abhishek SinghAbhishek Singh More articles by this author , Soundarya GanesanSoundarya Ganesan More articles by this author , Rohan BatraRohan Batra More articles by this author , Abhijit PatilAbhijit Patil More articles by this author , Arvind GanpuleArvind Ganpule More articles by this author , Ravindra SabnisRavindra Sabnis More articles by this author , Mahesh DesaiMahesh Desai More articles by this author , and ChandraMohan VaddiChandraMohan Vaddi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003248.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The Thulium fiber laser (TFL) is a promising new tool in the field of endoscopic laser lithotripsy, but is it efficacious in managing large stones using flexible ureteroscopy remains to be seen. Our objective was to analyse the clinical efficiency of TFL in large volume stones during retrograde intrarenal surgery. METHODS: Patients with large volume renal stones (>1000 mm3) and size of 15-25 mm, operated at two different centers, from May 2020 to April 2021, were enrolled in this study. Retrograde intrarenal surgery was performed using 60 W Superpulse thulium fiber laserTM (IPG Photonics, Russia). Demographic data, stone parameters, lasing time, total operating time were recorded, laser efficacy(J/mm3) and ablation speed(mm3/sec) were calculated. Complications were assessed using Clavien Dindo grading. NCCT KUB was done at 1month post operatively to calculate stone free rate. RESULTS: A total of 76 patients were included and analysed in the study. Mean stone volume was 1860.79±1172.61 (1169.27-2193.25) mm3, mean stone density was 1099.80 ± 313.65 (875.00-1317.00) HU, mean laser time was 537.79±689.89 (21.00-1080.00) sec, mean total operating time was 43.38±12.96 (35.00-51.25) min, mean laser efficacy was 20.30±15.5 (8.88-25.57) J/mm3, mean ablation speed was 1.32±0.7 (0.82-1.64) mm3/sec. A strong positive correlation between stone volume and ablation speed (r=0.659, p=0.000), a moderate negative correlation between volume and laser efficacy (J/mm3) (r=-0.392, p=0.000). With increasing volume of the stone, J/mm3 decreased significantly and ablation speed increased significantly (p<0.001). Complications occurred in 21.05% (16/76) patients, most of which were Clavien grades 1-2. Overall SFR is 96.05%. CONCLUSIONS: With an increase is stone volume, laser efficiency increases as less energy is required to ablate every mm3 of stone. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e311 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Abhishek Singh More articles by this author Soundarya Ganesan More articles by this author Rohan Batra More articles by this author Abhijit Patil More articles by this author Arvind Ganpule More articles by this author Ravindra Sabnis More articles by this author Mahesh Desai More articles by this author ChandraMohan Vaddi More articles by this author Expand All Advertisement PDF downloadLoading ...

MP35-09 SUPERPULSED THULIUM LASER&amp;[TRADE] FIBER VERSUS HIGH-POWER HOLMIUM:YAG LASER IN URETEROSCOPIC LASER LITHOTRIPSY: A CASE-CONTROL STUDY

You have accessJournal of UrologyCME1 Apr 2023MP35-09 SUPERPULSED THULIUM LASER&[TRADE] FIBER VERSUS HIGH-POWER HOLMIUM:YAG LASER IN URETEROSCOPIC LASER LITHOTRIPSY: A CASE-CONTROL STUDY Willian Ito, Nicholas Choi, George Letner, Dillon Prokop, Nicholas Genz, Bristol Whiles, Crystal Valadon, Md Islam, Mihaela Sardiu, Donald Neff, David Duchene, and Wilson Molina Willian ItoWillian Ito More articles by this author , Nicholas ChoiNicholas Choi More articles by this author , George LetnerGeorge Letner More articles by this author , Dillon ProkopDillon Prokop More articles by this author , Nicholas GenzNicholas Genz More articles by this author , Bristol WhilesBristol Whiles More articles by this author , Crystal ValadonCrystal Valadon More articles by this author , Md IslamMd Islam More articles by this author , Mihaela SardiuMihaela Sardiu More articles by this author , Donald NeffDonald Neff More articles by this author , David DucheneDavid Duchene More articles by this author , and Wilson MolinaWilson Molina More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003269.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Currently, a limited number of studies have compared high-power laser platforms for ureteroscopic lithotripsy (URS-L). We aimed to examine the outcomes of the SuperPulsed Thulium Fiber™ (SPTF) vs. the high-power holmium:YAG (HoYAG) laser for URS-L. METHODS: We conducted a retrospective chart review from 01/2019-12/2021 of patients undergoing elective URS-L for nephrolithiasis with HoYAG (Lumenis Pulse P120H™, 120W, Boston Sci®) or SPTF (Soltive™, 60W, Olympus®) laser modalities, regardless of stone size, location, or scope type. Exclusion criteria included patients with any urinary diversion, patients who did not undergo follow-up imaging or complete a 12-week post-procedural visit. Stone free status (SFS) was defined as the absence of stone fragments ≥2 mm on follow up imaging (ultrasound or CT scan). RESULTS: Of the initial 508 patients, 336 met inclusion criteria. Table 1 displays basic characteristics, with no significant difference between HoYAG and SPTF groups. Dusting technique was utilized more often in the SPTF group (18.5% vs. 6.2%, p=.039). Overall, SFS for HoYAG and SPTF were 85.9% vs. 85.3% (OR 1.07, CI 95% 0.56–2.06, p=0.82), respectively. In the stone location subgroup analysis, SFS results were comparable (Table 2). In our model, only BMI (OR 0.94, p=.002) and stone size (OR 0.94, p<.001) were correlated with SFS. When controlling for patients’ BMI, stone size, density, location, and use of ureteral access sheath, we found an adjusted OR 1.01 (CI 95% 0.46–2.23), with no statistical difference between laser modalities (p=0.96). CONCLUSIONS: Overall, there is no significant difference in SFS between HoYAG and SPTF groups, along with similar ablation efficiency and complication rates. Although ablation speed was significantly higher in the SPTF, total operative time was comparable. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e472 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Willian Ito More articles by this author Nicholas Choi More articles by this author George Letner More articles by this author Dillon Prokop More articles by this author Nicholas Genz More articles by this author Bristol Whiles More articles by this author Crystal Valadon More articles by this author Md Islam More articles by this author Mihaela Sardiu More articles by this author Donald Neff More articles by this author David Duchene More articles by this author Wilson Molina More articles by this author Expand All Advertisement PDF downloadLoading ...

MP35-19 A PROSPECTIVE RANDOMISED CONTROLLED STUDY BETWEEN MINIPCNL AND RIRS USING THULIUM FIBER LASER FOR LOWER POLE STONES 10-20 MM

You have accessJournal of UrologyCME1 Apr 2023MP35-19 A PROSPECTIVE RANDOMISED CONTROLLED STUDY BETWEEN MINIPCNL AND RIRS USING THULIUM FIBER LASER FOR LOWER POLE STONES 10-20 MM Chandra Mohan Vaddi, Ramakrishna Paidakula, Siddalinga Swamy P. M., Soundarya Ganesan, Hemnath U. A., Manas Babu B., and Rakesh Panda Chandra Mohan VaddiChandra Mohan Vaddi More articles by this author , Ramakrishna PaidakulaRamakrishna Paidakula More articles by this author , Siddalinga Swamy P. M.Siddalinga Swamy P. M. More articles by this author , Soundarya GanesanSoundarya Ganesan More articles by this author , Hemnath U. A.Hemnath U. A. More articles by this author , Manas Babu B.Manas Babu B. More articles by this author , and Rakesh PandaRakesh Panda More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003269.19AboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Abstract INTRODUCTION AND OBJECTIVE: Percutaneous nephrolithotomy (PCNL) has been recommended as the first choice for lower pole stone >10 mm. The objective of the study is to analyse whether Retrograde intrarenal surgery (RIRS) with newly upcoming Thulium fiber laser (TFL) can be an equally effective alternative. Primary Aim: To compare the different treatment modalities in terms of efficacy (stone free rate, need for auxiliary procedures) and safety (complication rate).Secondary aim: To compare the perioperative outcomes (operative time, fluoroscopic time, length of hospitalization). METHODS: Study Design: Prospective randomised controlled study Study period: October 2021 – May 2022 Study Population: Patients with lower pole stones 10-20 mm Group A - RIRS, Group B – Mini PCNL The energy source used was 60 W TFL (IPG Photonics, Massachusetts, United States) in both Group A and B. NCCT KUB was done at 2 months post operatively to calculate stone free rate. Institutional Ethics Committee approval was obtained. RESULTS: Mean stone size was 13.93±2.92 mm in Group A and 15.04±3.18 mm in Group B. In Group A, fluoroscopy time was significantly lower (31.96±14.34 vs 337.68±131.85, p<0.001), hospital stay was significantly lower (1.37±0.63 vs 3.24±1.01, p<0.001) and stone free rate (SFR) was comparable to Group B (88.9% vs 92.3%, p=1.000). There was no significant difference in operative time, complication rate or need for auxiliary procedure (Table 1). The ablation speed was significantly higher (9.47±5.61 vs 1.55±1.95, p<0.001), the laser efficacy was significantly lower (3.18±3.83 vs 16.43±7.07, p<0.001) and the laser time was significantly lower (141.04±86.98 vs 992.63±488.30, p<0.001) in Group B, as fragmentation rather than dusting was done with TFL. Table 1 CONCLUSIONS: RIRS with TFL for lower pole stones has SFR comparable to MiniPCNL, lower fluoroscopy time and hospital stay. No significant difference was found in operative time, complication rate or requirement of auxiliary procedure. Thus, RIRS with TFL is an effective alternative to miniPCNL for lower pole stones 10-20 mm Parameter RIRS with TFL (n=25) MiniPCNL with TFL(n=25) P value Age (years) 44.52 ± 14.21 48.64 ± 12.70 0.5091 Stone Size (mm) 13.93 ± 2.92 15.04 ± 3.18 0.1441 Volume (mm³) 1016.72 ± 341.11 1037.08 ± 428.83 0.4641 Density (HU) 1111.44 ± 252.61 1181.12 ± 288.14 0.3603 Operative Time (Minutes) 48.63 ± 8.57 50.80 ± 15.13 0.4521 Fluoroscopy Time (sec)*** 31.96 ± 14.34 337.68 ± 131.85 <0.0011 Complication rate 4/27 (14.8%) 5/25 (20%) 0.2134 Hospital Stay (Days)*** 1.37 ± 0.63 3.24 ± 1.01 <0.0011 Duration of Follow-Up 7.97 ± 2.47 8.29 ± 2.66 0.6503 Auxiliary Procedure (Yes) 2 (7.4%) 1 (4.0%) 1.0004 Overall Stone free rate 88.9% 92.3% 1.0004 ***Significant at p<0.05, 1: Wilcoxon-Mann-Whitney U Test, 2: Chi-Squared Test, 3: t-test, 4: Fisher's Exact Test Source of Funding: Self © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e477 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Chandra Mohan Vaddi More articles by this author Ramakrishna Paidakula More articles by this author Siddalinga Swamy P. M. More articles by this author Soundarya Ganesan More articles by this author Hemnath U. A. More articles by this author Manas Babu B. More articles by this author Rakesh Panda More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The Influence of Ablation Speed on the Synthesis of Carbon Nanostructures Via Pulsed Laser Ablation of Asphalt in Ethanol

Pulsed liquid laser ablation is considered a green method for the synthesis of nanostructures because there are no byproducts formed after the ablation. In this paper, a fiber laser of wavelength 1.064 µm, peak power of 1 mJ, pulse duration of 120 ns, and repetition rate of 20 kHz, was used to produce carbon nanostructures including carbon nanospheres and carbon nanorods from the ablation of asphalt in ethanol at ablation speeds of (100, 75, 50, 10 mm/s). The morphology, composition and optical properties of the synthesized samples were studied experimentally using FESEM, HRTEM, EDS, and UV-vis spectrophotometer. Results showed that the band gap energy decreased with decreasing the ablation speed (increasing the ablation time), the minimum mean particle size of the synthesized samples was 76 nm at an ablation speed of 100mm/s, while the maximum mean particle size was 98 nm at ablation speed of 50 mm/s, the nanospheres were agglomerated to form larger spherical nanoshapes. All the synthesized carbon nano colloids exhibited a blue-green PL emission. It was concluded that the presence of carbon nanorods has an effect on the optical properties of the synthesized nanospheres.

Enhanced Effect of Mining Dust Diffusion on Melting of the Adjacent Glacier: A Case Study in Xinjiang, China

Given the typical disturbances in the aqueous environment in the alpine area because of mining activities in Northwest China, a case study highlighting the enhanced effect of mining dust diffusion on the melting of the adjacent glacier is presented here. Initially, a three-dimensional numerical model of the local airflow field was established by considering the effects of both mines and glaciers using the FLUENT software. Then, the diffusion path and size range of dust particles from the mines were simulated by feeding the mining dust parameters into the above numerical model. Finally, a physical simulation experiment was performed to evaluate the influence of mining dust coverage on the glaciers. The major conclusions of this study were as follows: (1) The local airflow field in the target alpine area is controlled by the ‘heat and cold double-island effects’ formed by the mine and the glacier, and the wind circulation always takes place in a clockwise direction between the mining pit on the left and the glacier on the right. (2) In a given airflow field, there is a spread of mining dust from the mine to the glacier along the upper airflow. The arrival rates of the dust are 16.9% and 13.3% in winter and summer, respectively, and the horizontal distance of dust diffusion is inversely proportional to its particle size. (3) For an ice sample with a sectional area of 225 cm2 and a volume of 1000 mL, the melting rate increased by 4.5 mL/h with an increase of dust coverage by 10%. Furthermore, when compared with a control group without dust cover, the effect of a 28% increase in dust coverage is approximately equivalent to the effect of a 1 °C increase in temperature on the ablation speed of the glacier. The study results can provide a useful reference for the selection of mining sites and the control of mining dust diffusion in alpine regions with glaciers, thereby facilitating environmentally friendly mining in alpine regions.

Low temperature plasma ablation device for minimally invasive surgery.

This study introduces the design principle of a high-frequency square wave power supply, as well as the simulation and design process of a minimally invasive electrosurgical scalpel, which formed the low temperature plasma in saline solution. In order to verify the performance of the device, saline discharge experiments and pork ablation experiments were performed. An alternating high-frequency square-wave voltage was applied between coaxial double-layer electrodes with a spacing of 400 µm. The waveforms and amplitude of output voltage and current, conductance between electrodes, and output power were measured in saline discharge experiments. The results of pork ablation experiments with different power sources demonstrate that the device can generate low-temperature plasma for ablation rather than relying on thermal effects. The device can ablate pork under the driving of a 10V, 100kHz square wave voltage. In addition, the ablation speed and area will be greater with an increase in voltage or frequency.

Non-invasive localization of post-infarct ventricular tachycardia exit sites to guide ablation planning: a computational deep learning platform utilizing the 12-lead electrocardiogram and intracardiac electrograms from implanted devices.

Existing strategies that identify post-infarct ventricular tachycardia (VT) ablation target either employ invasive electrophysiological (EP) mapping or non-invasive modalities utilizing the electrocardiogram (ECG). Their success relies on localizing sites critical to the maintenance of the clinical arrhythmia, not always recorded on the 12-lead ECG. Targeting the clinical VT by utilizing electrograms (EGM) recordings stored in implanted devices may aid ablation planning, enhancing safety and speed and potentially reducing the need of VT induction. In this context, we aim to develop a non-invasive computational-deep learning (DL) platform to localize VT exit sites from surface ECGs and implanted device intracardiac EGMs. A library of ECGs and EGMs from simulated paced beats and representative post-infarct VTs was generated across five torso models. Traces were used to train DL algorithms to localize VT sites of earliest systolic activation; first tested on simulated data and then on a clinically induced VT to show applicability of our platform in clinical settings. Localization performance was estimated via localization errors (LEs) against known VT exit sites from simulations or clinical ablation targets. Surface ECGs successfully localized post-infarct VTs from simulated data with mean LE = 9.61 ± 2.61 mm across torsos. VT localization was successfully achieved from implanted device intracardiac EGMs with mean LE = 13.10 ± 2.36 mm. Finally, the clinically induced VT localization was in agreement with the clinical ablation volume. The proposed framework may be utilized for direct localization of post-infarct VTs from surface ECGs and/or implanted device EGMs, or in conjunction with efficient, patient-specific modelling, enhancing safety and speed of ablation planning.

Femtosecond Laser Texturization on Coated Steel

Surface textures such as laser-induced periodic surface structures (LIPSS) are of great interest to obtain industrial nanopatterns. In this work, plain uncoated 1.2344 steel with and without Chromium Nitride (CrN) and CrN plus diamond-like carbon (DLC) coatings were used in experiments. The laser texturing variables studied were the laser speed (3000–4000 mm/s) and the distance between laser lines (1–10 microns). These structures were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to obtain an overview of the roughness and to analyze the heights of the obtained structures. A two-dimension fast Fourier transform (2D-FFT) of the SEM images and its characteristic frequencies was used to assess the periodicity of the textured surfaces and thus quantify the far-range order. The speed of laser depth ablation is related to the laser energy density for each coating and textures are qualified using the FFT approach.