Laser Time Research Articles

The study of capillary discharge Ne-like 46.9 nm laser with a 2.5 mm inner diameter capillary

The capillary discharge 46.9 nm laser experiment was conducted using an alumina capillary of 35 cm in length and 2.5 mm in inner diameter. In terms of temporal characteristics, the duration (FWHM) of the laser pulse is 1.6 ns. The laser energy obtained with the 2.5 mm diameter capillary can be up to 1 mJ. For comparison, the laser energy achieved with the commonly used 3.2 mm diameter capillary is 305 μJ. With regard to spatial properties, the laser spot obtained at the optimal pressure using the 2.5 mm diameter capillary has a spatial distribution that is Gaussian-like, and the divergence's FWHM is 0.61 mrad. In order to investigate the effect of the capillary inner diameter on the 46.9 nm laser, we computed the plasma column characteristics near the lasing times observed with the 2.5 mm and 3.2 mm diameter capillaries.

Lasing from Doubly Degenerate Bound States in the Continuum.

This paper reports dual-mode vortex lasing with a topological charge of -2 via doubly degenerate bound states in the continuum. We patterned a photonic crystal slab with hexagonal TiO2 nanoparticles arranged in a hexagonal lattice to support doubly degenerate bound states in the continuum at the Γ point, and the finite array was truncated to have a square boundary. Because emission from bound states in the continuum at the Γ point is forbidden, lasing emerges at off-Γ points, where the double degeneracy is lifted, resulting in two lasing peaks close in wavelength. The coherence time of vortex lasing is about 1.4 ps under pulsed pumping with a width of 75 fs. Polarization- and angle-resolved spectral measurements reveal that the two lasing peaks show orthogonal polarization states.

Does tilt-retrograde intrarenal surgery enhance stone clearance and offer better surgical ergonomics in patients with renal calculi? A prospective randomized control study.

Retrograde intrarenal surgery (RIRS) is the standard treatment for renal calculi. Direct visualization and fragmentation are its major advantages. The variable stone clearance rates and the ergonomic challenges faced by urologists are a few limitations. Table tilt enhances stone clearance and improves surgical ergonomics by facilitating better access to stones and reducing procedural strain. In this prospective study, patients with intrarenal calculi were randomized into standard lithotomy RIRS (S-RIRS) and table-tilted RIRS (T-RIRS) groups. Specified table tilts were suggested for each of the stone locations. The outcomes with regard to stone clearance, operative and lasing time, and ergonomics were studied. About 100 patients were studied, with 50 in each group. The overall operating time and lasing time in the T-RIRS group were less than that in the S-RIRS group (P < 0.001). The complication rates were the same in both groups. Most surgeons felt that the surgical ergonomics was better in the T-RIRS group (P < 0.001). When stone-free status was analyzed, seven patients in the S-RIRS group and one in the T-RIRS group had residual stones. The mean Borg category-ratio 10 (CR-10) scores in the S-RIRS and T-RIRS groups were 4.18 and 2.20, respectively (P < 0.001). This is the first study to document the distinct advantages of T-RIRS and its benefits on surgical ergonomics. T-RIRS resulted in significantly shorter operative and lasing times, particularly for stones in lower calyces. Surgical ergonomics, assessed by the Borg CR-10 scale, were significantly better in the T-RIRS group. T-RIRS should become a standard of care for patients undergoing RIRS.

Comparing thulium fiber versus high power holmium laser in bilateral same sitting retrograde intrarenal surgery for kidney stones: Results from a multicenter study.

Traditionally, bilateral urolithiasis treatment involved staged interventions due to safety concerns. Recent studies have shown that same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) is effective, with acceptable complication rates. However, there's no clear data on the optimum laser for the procedure. This study aimed to assess outcomes of SSB-RIRS comparing thulium fiber laser (TFL) and high-power holmium:yttrium-aluminum-garnet (Ho:YAG) laser in a multicenter real-world practice. Retrospective analysis was conducted on patients undergoing SSB-RIRS from January 2015 to June 2022 across 21 centers worldwide. Three months perioperative and postoperative outcomes were recorded, focusing on complications and stone-free rates (SFR). A total of 733 patients were included, with 415 in group 1 (Ho:YAG) and 318 in group 2 (TFL). Both groups have similar demographic and stone characteristics. Group 1 had more incidence of symptomatic pain or hematuria (26.5% vs. 10.4%). Operation and lasing times were comparable. The use of baskets was higher in group 1 (47.2% vs. 18.9%, p<0.001). Postoperative complications and length of hospital stay were similar. Group 2 had a higher overall SFR. Multivariate regression analysis indicated that age, presence of stone at the lower pole, and stone diameter were associated with lower odds of being stone-free bilaterally, while TFL was associated with higher odds. Our study shows that urologists use both lasers equally for SSB-RIRS. Reintervention rates are low, safety profiles are comparable, and single-stage bilateral SFR may be better in certain cases. Bilateral lower pole and large-volume stones have higher chances of residual fragments.

Time-dependent 532 nm laser irradiation for tuning in optical, structural, and surface wettability changes of Te/In2Se3 thin films for optoelectronic applications

Laser irradiation for tuning the optoelectronic parameters of semiconducting thin films is widely applicable and has many benefits. The aim of the study is 532 nm laser irradiation of Te/In2Se3 film at different laser exposure time scales. The bilayer structure and its conversion to a single layer with laser annealing were confirmed from cross-sectional scanning electron microscopy. At the same time, the element's appearance was found in the EDX analysis. FESEM probed the corresponding surface structure change. XRD and Raman's spectroscopy analyzed the increase in crystallinity with laser irradiation by mixing Te into the In2Se3 layer and related microstructural changes. The shift in Raman peak with lasing time signifies the effect of time of exposure. There is a systematic decrement in the transmittance of the films. Also, the absorption edge shift resulted in the decrement in bandgap with laser irradiation. The static refractive index and optical density increased as well. The skin depth was decreased with a minimal change in the optical electronegativity. The nonlinear refractive index increased from 1.638 × 10–9 esu to 1.773 × 10–9 esu by 60 min laser irradiation. Similarly, there was an increment in 3rd-order nonlinear susceptibility from 1.58 × 10–10 esu to 1.73 × 10–10 esu. The surface wettability test confirmed the hydrophilic nature of the samples with decreasing hydrophilicity by laser irradiation. The tuning in different properties of the Te/In2Se3 film by laser irradiation is suitable for various optoelectronic applications.

Delayed hematuria after prostatic photovaporization: risk factors to know.

characterize delayed hematuria (DH) after photoselective vaporization of the prostate (PVP) and identify its associated risk factors. 1014 patients who underwent PVP at an expert center, from September 2005 through December 2021, were prospectively enrolled in a database registry. Risk factors of DH included age, prostate volume, ASA score, history of BPH surgery, history of prostate cancer, use of anticoagulation or 5ARIs, concomitant procedure, operative factors, and the duration of follow-up. The median operating time was 60 ± 11 min. The median specific applied energy was 318,500 Joules ± 101,347. After PVP, the mean catheterization duration was 1.6 days with a postoperative hospitalization time of 1.8 days. The median follow-up was 52 months (range 2-95months). Hematuria occurred in 206 patients (20.3%), with 10% requiring an ER visit and 8.3% requiring hospital admission, transfusion or endoscopic clot removal. Almost 80% of hematuria episodes occurred within the first 3months. The overall retreatment rate for clot retention was 3.7% after a mean time of 50months. Hematuria-free survival was 97.2% after 1year, and 89.3% after 4years. Delayed hematuria occurred in 32 patients (3.1%). In the multivariate analysis, age, preoperative prostate volume, anticoagulant use, total applied energy, lasing time and operative time were identified as risk factors for delayed hematuria after PVP. Larger prostate volume, longer operative time, longer lasing time, and use of oral anticoagulation increase the odds of delayed hematuria after PVP, while older age is protective.

Is Bigger Better? Comparison of 150 µm and 200 µm Thulium Fiber for In Situ Lower-Pole Lithotripsy.

Introduction: The thulium fiber laser (TFL) generates a focused beam, which can be transmitted to laser fibers with small core diameters and may facilitate in situ lower-pole lithotripsy. This study compares lithotripsy performance of the 150 and 200 µm TFL in a lower pole benchtop kidney model. Materials and Methods: Using a 3D model printed from an actual kidney, in situ laser lithotripsy was performed on 1 cm lower-pole BegoStones (calcium oxalate monohydrate consistency) using four different settings (all 20W) and two fiber sizes (150 and 200 µm). Procedure time, laser time, total pulse energy, and fiber stripping were compared between the two fibers using an ANOVA or independent t-test. Results: The 150 µm fiber at 0.2 J × 100 Hz had the shortest lasing and procedure time (17.3 and 18.5 minutes) and lowest total pulse energy (20.75 kJ) compared with other study arms (p < 0.001). Overall procedure time, lasing time, and total pulse energy were significantly different between the 8 settings (p < 0.001 for all). At higher frequency (100 and 200 Hz), lasing time was significantly faster compared with 20 and 50 Hz (19.9 vs 27.3 minutes; p < 0.001). Furthermore, the average total procedure time was shorter with 150 µm compared with 200 µm regardless of settings (23.2 vs 29.8 minutes; p < 0.001). Conclusion: The 150 µm fiber results in shorter procedure and lasing time at lower total energy levels during lower-pole in situ lithotripsy. Overall, the fastest setting was 0.2 J and 100 Hz with the 150 µm fiber. Smaller laser fibers can potentially allow more efficient in situ laser lithotripsy with better irrigation and visibility at higher deflection angles.

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.

First prospective clinical assessment of the ILY® robotic flexible ureteroscopy platform.

To present the initial prospective clinical assessment of the ILY® robotic ureteroscopy manipulator platform, focusing on its safety and effectiveness. Data gathered from 31 kidney units which underwent elective robotic flexible ureteroscopy (FURS) for renal stone management utilizing the ILY® robotic system. Patient demographics, stone characteristics, surgical durations, perioperative and post-operative complications, and follow-up parameters were collected. Our primary outcome was evaluating the efficacy and safety of the ILY® robotic ureteroscopy for treating kidney stones. Therefore, we analyzed complication rates, surgical durations, and the stone-free rate during follow-up. Our cohort consisted of 29 patients, presenting with 45 stones with a median volume of 736.22 mm3. The median operation time was 85 min, accompanied by 3 min for robot draping, 3.5 min for robot docking, 48 min of console operation, and lasing time of 36.75 min. Post operative stay for all patients was 1 day, while complications were observed in 9.68% of cases. Notably, all complications were classified as CVD (Clavien-Dindo) class 1 due to pain requiring emergency department visit. The stone-free rate achieved was 93.55%, and none of the patient required reoperation for the treated stone. In the first prospective clinical experience of the ILY® robotic FURS, we demonstrated its efficacy and safety. To further investigate its clinical practical value, additional investigations are warranted, including direct comparative analyses with manual flexible ureteroscopy techniques.

Factors Affecting Holmium Laser Efficiency: Comparison of Laryngeal Mask Airway and Endotracheal Intubation During Ureteroscopy for Renal Stones.

Introduction: Holmium laser lithotripsy is a standard energy source used for treatment of kidney stones during flexible ureteroscopy. Efficiency of laser surgery may be affected by patient and operator characteristics or perioperative management. Here, we sought to examine intraoperative data from patients undergoing high frequency dusting with high-powered holmium laser lithotripsy to evaluate surgical and demographic factors associated with lasing efficiency (LE). Methods: A total of 82 intraoperative reports were analyzed from an ongoing laser lithotripsy clinical trial evaluating the Lumenis Pulse™ 120H holmium laser with renal stones up to 20 mm in diameter with and without Moses 2.0 technology. For each case, the total pause time between lasing activations was corrected to remove lengthy pauses and divided by the total lasing time to calculate an efficiency percentage. This was then compared with patient demographics, anesthesia administration, stone burden, postoperative complications, and stone-free rates using both univariate and multivariate analyses. Results: Of the 82 included patients, 36 received endotracheal tube (ETT) intubation and 46 had a laryngeal mask airway (LMA). Patients with ETT had significantly higher LE (78.7%) compared to those with an LMA (73.3%) in our univariate analysis (p < 0.01) as well as in the multivariate model that adjusted for maximum stone size, number of stones, stone density, and patient body mass index (p < 0.05). There was also significantly higher mean LE in patients with no postoperative complications (76.3%) compared to those with any grade (I-V) Clavien-Dindo complication within 30 days after surgery (70.0%) (p < 0.05). Conclusions: Flexible ureteroscopy and laser lithotripsy cases with higher LE are associated with lower rates of postoperative complications. The data also support the use of ETT over LMA to improve overall LE; however, this remains one consideration among many for choosing anesthesia administration. Clinical Trial Registration number: NCT04505956.

Predictors of early catheter replacement after HoLEP. Results from a high-volume laser center.

The aim of the study was to investigate clinical and surgical factors associated with early catheter replacement in patients treated with Holmium Laser Enucleation of the Prostate (HoLEP). Data of patients treated with HoLEP at our Institution by a single surgeon from March 2017 to January 2021 were collected. Preoperative variables, including non-invasive uroflowmetry and abdominal ultrasonography (US), were recorded. Bladder wall modifications (BWM) at preoperative US were defined as the presence of single or multiple bladder diverticula or bladder wall thickening 5 mm. Clinical symptoms were assessed using validated questionnaires. Only events occurred within the first week after catheter removal were considered. Overall, 305 patients were included, of which 46 (15.1%) experienced early catheter replacement. Maintenance of anticoagulants/antiplatelets (AC/AP) therapy at surgery (p=0.001), indwelling urinary catheter (p=0.02) and the presence of BWM (p=0.001) were more frequently reported in patients needing postoperative re-catheterization. Intraoperative complications (p=0.02) and median lasing time (p=0.02) were significantly higher in this group. At univariate analysis, indwelling urinary catheter (p=0.02), BWM (p=0.01), ongoing AC/AP therapy (p=0.01) and intraoperative complications (p=0.01) were significantly associated with early catheter replacement. At multivariate analysis, indwelling urinary catheter (OR: 1.28; p=0.02), BWM (OR: 2.87; p=0.001), and AC/AP therapy (OR: 2.21; p=0.01) were confirmed as independent predictors of catheter replacement. In our experience the presence of indwelling urinary catheter before surgery, BWM and the maintenance of AC/AP therapy were shown to be independent predictors of early catheter replacement after HoLEP.

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.

Surgical reintervention requirements following GreenLight PVP: A single-center experience using three different laser device models

ABSTRACT Objective To assess the incidence, risk factors, and timing of specific causes of reoperations following PVP. Material and Methods A retrospective analysis of data on men who underwent GreenLight PVP between 2004 and 2019 in a single center and required surgical intervention for bladder neck contracture (BNC), urethral stricture (US), or persistent/recurrent prostate adenoma. Results The overall rate of reoperations was 13.8% during a 61-month median follow-up of 377 patients. Reoperations were due to BNC, US, and adenoma in 7.7%, 5.6%, and 4.8% of cases, respectively. The median interval until reoperation for US (11 months) was significantly shorter. None of the risk factors had any relevance to US. In patients who underwent reoperation for BNC, lasing time and energy were significantly lower, and the prostate volume was smaller; however, the multivariate analysis only identified shorter lasing time as a predictor. In patients who had reoperation for persistent/recurrent adenoma, the PSA was increased, while the prostate volume was non-significantly high, and performance by less-experienced surgeons was associated with a higher rate of reoperations (p < 0.05). A longer lasing time predicted an increased risk of reoperation for adenoma in multivariate analysis. Conclusions An unselective utilization of PVP may result in a relatively high rate of reoperations. The correlation of BNC with shorter lasing time may imply a higher risk after PVP of smaller prostates. A longer lasing time predicts an increased risk of reoperation due to persistent/recurrent adenoma, which may be related to higher prostate volumes and inefficient PVP by less-experienced surgeons.

Holmium laser enucleation of the prostate (HoLEP) is safe and effective in patients with high comorbidity burden.

We assessed the efficacy and safety of holmium laser enucleation of the prostate (HoLEP) in patients with high comorbidity burden. Data from patients treated with HoLEP at our academic referral center from March 2017 to January 2021 were prospectively collected. Patients were divided according to their CCI (Charlson Comorbidity Index). Perioperative surgical data and 3-month functional outcomes were collected. Out of 305 patients included, 107 (35.1%) and 198 (64.9%) were classified as CCI ≥ 3 and < 3, respectively. The groups were comparable in terms of baseline prostate size, symptoms severity, post-void residue and Qmax. The amount of energy delivered during HoLEP (141.3 vs. 118.0 KJ, p=0.01) and lasing time (38 vs 31 minutes, p=0.01) were significantly higher in patients with CCI ≥ 3. However, median enucleation, morcellation and overall surgical time were comparable between the two groups (all p>0.05). Intraoperative complications rate (9.3% vs. 9.5%, p=0.77), median time to catheter removal and hospital stay were comparable between the two cohorts. Similarly, early (30 days) and delayed (>30 days) surgical complications rates were not significantly different between the two groups. At 3-month follow up, functional outcomes using validated questionnaires did not differ between the two groups (all p>0.05). HoLEP represents a safe and effective treatment option for BPH also in patients with high comorbidity burden.

Comparison Between Holmium:YAG Laser with MOSES Technology vs Thulium Fiber Laser Lithotripsy in Retrograde Intrarenal Surgery for Kidney Stones in Adults: A Propensity Score-matched Analysis From the FLEXible Ureteroscopy Outcomes Registry.

We evaluated stone-free rate and complications after flexible ureteroscopy for renal stones, comparing thulium fiber laser and holmium:YAG laser with MOSES technology. Data from adults who underwent flexible ureteroscopy in 20 centers worldwide were retrospectively reviewed (January 2018-August 2021). Patients with ureteral stones, concomitant bilateral procedures, and combined procedures were excluded. One-to-one propensity score matching for age, gender, and stone characteristics was performed. Stone-free rate was defined as absence of fragments >2 mm on imaging within 3 months after surgery. Multivariable logistic regression analysis was performed to evaluate independent predictors of being stone-free. Of 2,075 included patients, holmium:YAG laser with MOSES technology was used in 508 patients and thulium fiber laser in 1,567 patients. After matching, 284 patients from each group with comparable baseline characteristics were included. Pure dusting was applied in 6.0% of cases in holmium:YAG laser with MOSES technology compared with 26% in thulium fiber laser. There was a higher rate of basket extraction in holmium:YAG laser with MOSES technology (89% vs 43%, P < .001). Total operation time and lasing time were similar. Nine patients had sepsis in thulium fiber laser vs none in holmium:YAG laser with MOSES technology (P = .007). Higher stone-free rate was achieved in thulium fiber laser (85% vs 56%, P < .001). At multivariable analysis, the use of thulium fiber laser and ureteral access sheath ≥8F had significantly higher odds of being stone-free. Lasing time, multiple stones, stone diameter, and use of disposable scopes showed significantly lower odds of being stone-free. This real-world study favors the use of thulium fiber laser over holmium:YAG laser with MOSES technology in flexible ureteroscopy for renal stones by way of its higher single-stage stone-free rate.

A study comparing dusting to basketing for renal stones ≤ 2 cm during flexible ureteroscopy.

To compare the dusting efficiency and safety with basketing for treating renal stones ≤ 2 cm during flexible ureteroscopy (fURS). This study included 218 patients with renal stones ≤ 2 cm treated with fURS. Among them, 106 patients underwent dusting, and 112 patients underwent fragmentation with basket extraction. All patients were followed up for 3 months postoperatively. The operating time, lasing time, stone-free rate (SFR) and complication rate were compared. The mean stone size in the dusting group was 1.3 cm, whereas 1.4 cm in the basketing group. The mean operative time was significantly lower in the dusting group than in the basketing group (43.1±11.7 minutes VS 60.5±13.4 minutes, P < 0.05), but the lasing time was significantly longer for the dusting group than for the basketing group (17.7±3.9 minutes VS 14.1±3.6 minutes, P < 0.05). SFR was significantly higher in the basketing group immediately after the operation and follow-up after 1 month (76.8% vs 55.7%, P= 0.001 and 88.4% vs 78.3%, P = 0.045). However, the SFR was similar for both groups (88.8% in the dusting group vs. 90.2% in the basketing group) after 3 months postoperatively. There was no statistical difference in the complication rates between the two groups. Dusting has advantages in shortening the operation time and reducing the operation cost, but the lasing time was longer compared with the basketing. Although there is no difference in long-term effect, basketing is superior to dusting in terms of short-term SFR. Moreover, dusting should be avoided in some special cases and basketing a better choice. Both techniques are effective for the treatment of renal stones ≤ 2 cm and choice depends on patient demographic and stone characteristics.

PD45-07 THULIUM FIBRE VERSUS MOSES LASER LITHOTRIPSY FOR RETROGRADE INTRARENAL SURGERY: IS THERE A CLEAR WINNER? OUTCOMES FROM THE FLEXOR STUDY

You have accessJournal of UrologyCME1 Apr 2023PD45-07 THULIUM FIBRE VERSUS MOSES LASER LITHOTRIPSY FOR RETROGRADE INTRARENAL SURGERY: IS THERE A CLEAR WINNER? OUTCOMES FROM THE FLEXOR STUDY Ee Jean Lim, Khi Yung Fong, Danielle Castellani, Olivier Traxer, Bhaskar Kumar Somani, Ben Chew, and Vineet Gauhar Ee Jean LimEe Jean Lim More articles by this author , Khi Yung FongKhi Yung Fong More articles by this author , Danielle CastellaniDanielle Castellani More articles by this author , Olivier TraxerOlivier Traxer More articles by this author , Bhaskar Kumar SomaniBhaskar Kumar Somani More articles by this author , Ben ChewBen Chew More articles by this author , and Vineet GauharVineet Gauhar More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003358.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Currently two technologies, super pulsed thulium fibre laser (TFL) and the Moses laser using the holmium fibre (HLM) are most effective for lithotripsy by flexible ureteroscopy(f-URS) for renal stones. The primary aim of our study is to compare and contrast the outcomes of these two laser technologies in our cohort of 2075 patients enrolled in the FLEXible ureteroscopy Outcomes Registry (FLEXOR) project .Our secondary aim is to evaluate if either technology was superior in stone free rate(SFR) and complications. METHODS: Patients who underwent f-URS for renal stones between January 2018 and August 2021 were retrospectively analysed. Patients aged<18 years, ureteral stones, concomitant bilateral procedures, or musculoskeletal abnormalities were excluded .Kolmogorov-Smirnov test was used to check data distribution for normality. Continuous data presented as mean and standard deviation and categorical data as absolute numbers and percentages. Analyses repeated after propensity score matching (PSM) to adjust for bias. One-to- one matching for age, gender, stone location, single/multiple stone, and HU estimated. Univariate logistic regression analysis was performed to evaluate factors for SFR from PSM population. Multivariable assessment done and estimated as odds ratio (OR) and 95% confidence interval (CI), and p-value. RESULTS: Before PSM matching, there were 508 patients in the HLM and 1567 in the TFL groups. The population in the TFL group were significantly younger (mean age 46.44±14.01 years), larger stone diameter (14.35±7.37 mm p<0.001), single stones (65.6% vs 42.5%, p<0.001) and stones located in the pelvis (46.4% vs 17.1%, p<0.001).Mean stone density was significantly higher in HLM group (1115±386 vs 1068±331 HU, p=0.016). Mean lasing time was significantly longer with HLM (29.40±14.25 vs 20.90±16.47 minutes, p=0.01) and longer total surgical time in TFL (73.41±51.14 vs 61.03±29.47 minutes, p<0.001).TFL group experienced more infective complications. SFR was significantly higher in the TFL group (89.9% vs 61.6%, p<0.001). There were 297 patients in each group after PSM matching. Pure dusting was performed in 5.7% of the HLM group compared with 28.8% in TFL group. A larger proportion of patients required stone extraction in the HLM group compared to the TFL group. (89.2% vs 40.5%, p<0.001). Lasing time did not differ significantly. Total operation time was significantly longer in the TFL group (74.75±51.38 vs 62.42±29.98 minutes, p<0.001). There were 11 patients who had sepsis in the TFL group and none in the HLM group (p=0.002). SFR was significantly higher with TFL (84.8% vs 56.6%, p<0.001). CONCLUSIONS: In our global study TFL was the winner with significantly higher SFR and a better laser for treating renal stones by dusting especially in larger stones A higher rate of sepsis cautions its careful use. MOSES laser lithotripsy is equally effective for fragmentation and extraction but need for ancillary treatment for RF was higher and urologists should counsel patients accordingly. Source of Funding: NIL © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1165 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ee Jean Lim More articles by this author Khi Yung Fong More articles by this author Danielle Castellani More articles by this author Olivier Traxer More articles by this author Bhaskar Kumar Somani More articles by this author Ben Chew More articles by this author Vineet Gauhar More articles by this author Expand All Advertisement PDF downloadLoading ...

Time-dependent laser irradiation-induced kinetics of changes in linear–nonlinear optical properties of Bi15In20Se65 thin films for IR applications

The current research depicts the laser irradiation-induced effect on the optoelectrical and structural properties of thermally evaporated Bi15In20Se65 thin films with different exposure durations (0, 10, 20, 30, 60, and 90 min). The illumination effect under different lasing times leads to the retention of amorphous nature, indicating the short-range ordering inside the matrix. An improvement in the homogeneous and smooth texture of the film surface even after irradiation has been observed. However, significant optical changes have been noticed with different exposure durations. Transparency decreased with the exposure time, whereas an increment in the absorption coefficient with red shifting in the absorption edge was observed. Broad transparency and less absorption over the infrared region make these films promising for infrared optics such as temperature detection, energy management, monitoring, night vision, etc. Laser illumination allowed bond rearrangements that led to an increase in defect states over the forbidden gap regime and reduced the bandgap from 1.02 to 0.94 eV, confirming the photodarkening nature. This consequently enhanced the Urbach energy and electron–phonon interactions. Both extinction coefficient and refractive index enhanced with lasing duration, indicating an increment in the scattering centers with the lasing duration. The increase in the lasing time results in the increase of interband transitions, which might be due to the increase of carrier concentrations in the system. The non-linear susceptibility (χ(3)) and refractive indices showed enhancement with exposure duration. The observed non-linear refractive index (SI) is 20–30 times greater than silica. This reduction of Eg and enhancement in non-linearity improves the occurrence of two-photon absorption, signifying the potentiality for photonic devices. The hydrophilic nature of laser-irradiated films makes them suitable for applications such as self-cleaning, antifouling, and antifogging as coating materials.

Comparative study of thulium fiber laser versus holmium:yttrium-aluminum-garnet laser for ureteric stone management with semi-rigid ureteroscopy: A prospective, single-center study

ObjectiveTo compare the efficacy and safety of thulium fiber laser (TFL) and holmium:yttrium-aluminum-garnet (Ho:YAG) laser for ureteric stone management with semi-rigid ureteroscopy. MethodsIn a prospective study from January 2020 to December 2021, we compared 40 patients in each group who underwent semi-rigid ureteroscopic lithotripsy with TFL and that with Ho:YAG laser. Stone volume, stone density, stone fragmentation rates, total lasing time, total operative time, endoscopic vision, retropulsion and stone free rates were analyzed in both groups and compared. ResultsMean stone volume was comparable in the TFL group and the Ho:YAG laser group (282.45 [standard deviation, SD 139.79] mm3vs. 279.49 [SD 312.52] mm3; p=0.964). Mean stone density was also comparable in the TFL group and the Ho:YAG laser group (1135.30 [SD 317.04] Hounsfield unit vs. 1131.75 [SD 283.03] Hounsfield unit; p=0.959). The mean stone fragmentation rates calculated as stone volume divided by lasing time were 25.85 (SD 10.61) mm3/min and 21.37 (SD 14.13) mm3/min in the TFL group and the Ho:YAG laser group, respectively (p=0.113). The mean total lasing time (10.15 [SD] 4.69 min vs. 11.43 [SD 4.56] min; p=0.222), mean operative time (25.13 [SD 9.51] min vs. 25.54 [SD 10.32] min; p=0.866), and mean total hospital stay (2.62 [SD 0.77] days vs. 2.61 [SD 0.84] days; p=0.893) were comparable in the TFL group and in the Ho:YAG group. The vision was better and retropulsion was less in the TFL group. The stone-free rate at 1 month postoperatively was slightly better in the TFL group (100% vs. 90%; p=0.095). ConclusionTFL technology was associated with the comparable total surgical time, total lasing time, and stone fragmentation rate with Ho:YAG laser. However, TFL had better endoscopic vision, lesser stone retropulsion, and slightly better stone-free rates.

Moses and Moses 2.0 for Laser Lithotripsy: Expectations vs. Reality.

Moses technology was born with the aim of controlling the Moses effect present in every single Ho:YAG laser lithotripsy. The capacity to divide the energy pulse into two sub-pulses gained popularity due to the fact that most of the energy would be delivered in the second pulse. However, is this pulse modulation technique really better for endocorporeal laser lithoripsy? A review of the literature was performed and all relevant clinical trials of Moses 1.0 and 2.0, as well as the lab studies of Moses 2.0 carried out up to June 2022 were selected. The search came back with 11 clinical experiences (10 full-text clinical trials and one peer-reviewed abstract) with Moses 1.0 and Moses 2.0, and three laboratory studies (peer-reviewed abstracts) with Moses 2.0 only. The clinical experiences confirmed that the MT (1.0) has a shorter lasing time but lower laser efficacy, because it consumes more J/mm3 when compared with the LP Ho:YAG laser (35 W). This gain in lasing time did not provide enough savings for the medical center. Additionally, in most comparative studies of MT (1.0) vs. the regular mode of the HP Ho:YAG laser, the MT did not have a significant different lasing time, operative time or stone-free rate. Clinical trials with Moses 2.0 are lacking. From what has been published until now, the use of higher frequencies (up to 120 Hz) consumes more total energy and J/mm3 than Moses 1.0 for similar stone-free rates. Given the current evidence that we have, there are no high-quality studies that support the use of HP Ho:YAG lasers with MT over other lasers, such as LP Ho:YAG lasers or TFL lasers.