Comparison of holmium:yttrium-aluminium-garnet (YAG), thulium fiber laser, and pulsed thulium:YAG lasers on soft tissue: an ex vivo study.

OBJECTIVES: To assess laser-tissue interactions through ablation, coagulation, and carbonisation characteristics in a non-perfused porcine kidney model between three pulsed lasers: holmium (Ho): yttrium-aluminium-garnet (YAG), thulium fiber laser (TFL), and pulsed thulium (p-Tm):YAG. MATERIALS AND METHODS: A 150-W Ho:YAG, a 60-W TFL, and a 100-W p-Tm:YAG lasers were compared. The laser settings that can be set identically between the three lasers and be clinically relevant for prostate laser enucleation were identified and used on fresh, unfrozen porcine kidneys. Laser incisions were performed using stripped laser fibers of 365 and 550 µm, set at distances of 0 and 1 mm from the tissue surface at a constant speed of 2 mm/s. Histological analysis evaluated shape, depth, width of the incision, axial coagulation depth, and presence of carbonisation. RESULTS: Incision depths, widths, and coagulation zones were greater with Ho:YAG and p-Tm:YAG lasers than TFL. Although no carbonisation was found with the Ho:YAG and p-Tm:YAG lasers, it was common with TFL, especially at high frequencies. The shapes of the incisions and coagulation zones were more regular and homogeneous with the p-Tm:YAG laser and TFL than with Ho:YAG laser. Regardless of the laser used, short pulse durations resulted in deeper incisions than long pulse durations. Concerning the distance, we found that to be effective, TFL had to be used in contact with the tissue. Finally, 365-µm fibers resulted in deeper incisions, while 550-µm fibers led to wider incisions and larger coagulation zones. CONCLUSION: Histological analysis revealed greater tissue penetration with the p-Tm:YAG laser compared to the TFL, while remaining less than with Ho:YAG. Its coagulation properties seem interesting insofar as it provides homogeneous coagulation without carbonisation, while incisions remained uniform without tissue laceration. Thus, the p-Tm:YAG laser appears to be an effective alternative to Ho:YAG and TFL lasers in prostate surgery.

Do Stone Characteristics and Laser Fiber Size Affect Ho: YAG Laser Time and Energy During Ureteroscopy?

Objective: To assess the correlation of attenuation value measured as HU in Non-contrast computed tomography, stone size, location, fibre size and stone composition with Holmium: yttrium-aluminium garnet (Ho: YAG) laser parameters including, cumulative laser energy and final laser time. Materials and Methods:  We prospectively analyzed 118 patients undergoing flexible/semirigid ureteroscopy and Holmium: YAG laser lithotripsy from October 2022 to October 2023 at Mogadishu Urological Centre. Our study parameters encompass preoperative stone characteristics determined in NCCT (stone size, attenuation value, and stone location), fibre size, cumulative laser energy and time, overall operative time, and postoperative stone composition analysis. Results: There were 118 patients eligible for our prospective study. In the logistic regression model for retrograde intrarenal surgery with a fibre size of 272 µm, cumulative laser energy showed a significant difference among stone size, location, fibre size, and calcium oxalate stones (P > 0.05). However, no significant difference was noticed in the attenuation value (P = 0.078) (R2 = 0.053). Our analysis showed a positive significance among all the parameters (P < 0.05) for laser time. In logistic regression for a rigid ureteroscope with a fibre size of 365 µm, cumulative laser energy showed a significant difference between the location stone and fibre size (P < 0.05) (R2 = 0.09). However, no significant difference was seen among stone size, attenuation value, and calcium oxalate stones (P > 0.05). For laser time, our analysis showed a positive significance among all parameters except the calcium oxalate stones, which showed no significant difference (P > 0.05). Conclusion: Our study showed that stone location, hardness, and fibre size are the most critical factors influencing the outcome of Ho: YAG laser parameters. The study revealed that CaOMH stones require more time to disintegrate into smaller ones, while PH-dependent stones such as carbonate apatite may require less time to fragment.

Monitoring Intrarenal temperature changes during Ho: YAG laser lithotripsy in patients undergoing retrograde intrarenal surgery: a novel pilot study.

Ho: YAG laser lithotripsy is widely used for urinary stone treatment, but concerns persist regarding its thermal effects on renal tissues. This study aimed to monitor intrarenal temperature changes during kidney stone treatment using retrograde intrarenal surgery with Ho: YAG laser. Fifteen patients were enrolled. Various laser power settings (0.8 J/10 Hz, 1.2 J/12 Hz) and irrigation modes (10 cc/min, 15 cc/min, 20 cc/min, gravity irrigation, and manual pump irrigation) were used. A sterile thermal probe was attached to a flexible ureterorenoscope and delivered into the calyceal system via the ureteral access sheath. Temperature changes were recorded with a T-type thermal probe with ± 0.1 °C accuracy. Laser power significantly influenced mean temperature, with a 4.981 °C difference between 14 W and 8 W laser power (p < 0.001). The mean temperature was 2.075 °C higher with gravity irrigation and 2.828 °C lower with manual pump irrigation (p = 0.038 and p = 0.005, respectively). Body mass index, laser power, irrigation model, and operator duty cycle explained 49.5% of mean temperature variability (Adj. R2 = 0.495). Laser power and operator duty cycle positively impacted mean temperature, while body mass index and specific irrigation models affected it negatively. Laser power and irrigation rate are critical for intrarenal temperature during Ho: YAG laser lithotripsy. Optimal settings and irrigation strategies are vital for minimizing thermal injury risk. This study underscores the need for ongoing research to understand and mitigate thermal effects during laser lithotripsy.

High-power Holmium:Yag lithotripsy in bladder urolithiasis: Is it safe and effective? A combined clinical and experimental study.

Objective: To evaluate the efficacy and safety of Holmium: Yttrium-Aluminum-Garnet (Ho:YAG) laser in bladder lithotripsy using high-power settings > 100 W. Materials and Methods: A combined experimental and clinical study was conducted. The Quanta Cyber: Ho 150 with a 550 µm Quanta optical fiber was utilized in all set-ups. Ablation rates for soft and hard artificial stones were tested in vitro using 100 W and 20 W power settings. In the experiment, a porcine bladder was used. The optical fiber was inserted through a rigid cystoscope, whilst a K-type thermocouple was inserted in the bladder dome. The tested high-power settings were 152 W, 120 W and 105 W. In every trial, the lasing time was over 60 s. In the clinical study, 35 patients underwent transurethral high-power bladder lithotripsy. Laser settings were set between 100 W and 150 W. Results: Stone mass (stone weight) was significantly lower after stone ablation independently of the stone type or the laser settings. Significantly higher mass decrease and ablation rate were detected in high-power compared to low-power settings. In the experiment, the highest temperature recorded was 32°C at 152 W. At 120 W and 105 W, the peak temperatures didn't reach 30°C. In the clinical study, a stone-free rate of 100% and a mean operative time of 43 ± 18 min were reported. All patients stayed in the hospital for one day except for one who presented minor hematuria. Additional complications did not occur. Conclusion: Ho:YAG laser lithotripsy > 100 W is an effective, fast and safe modality for the treatment of bladder calculi.

Comparison of high and low pulse energy dusting protocols using holmium: YAG laser in flexible ureteroscopy for treatment of renal stones.

Objectives: The management of renal stones, particularly those less than 2 cm in diameter, has changed with the development of endourological techniques, among which flexible ureteroscopy (FURS) using laser for lithotripsy has become a cornerstone. This study aims to compare the effectiveness of high pulse energy versus low pulse energy laser settings in renal stone dusting by Holmium YAG laser. Patients and Methods: This prospective randomized study was conducted between September 2021 and November 2023 to compare the efficacy and safety of high energy versus low-energy pulse settings using a Holmium: YAG laser dusting of renal stones less than 2 cm in diameter. A total of 174 adult patients were included, divided equally into high- and low-pulse energy groups, based on the energy settings of the laser high energy (ranged from 1.2-2.5 Joules and frequency of 8 hz) and low energy (less than 0.5 Joules and frequency ≥ 15 hz) using the dusting technique with non-touch non-stop approach. The study sought to evaluate the impact of these settings on stone fragmentation efficiency, operative time, laser energy consumption, and postoperative outcomes, including stone-free rates and complications. Results: The study involved 174 patients who underwent renal stone lithotripsy and showed that using high pulse energy laser dusting settings significantly reduced operative times and more rapid dusting compared to low pulse energy settings, without affecting the stone-free rate. The study observed no significant differences in stone size or location between both groups. Minor postoperative complications were similar between both groups, indicating high pulse energy settings for lithotripsy dusting. Conclusion: The efficacy of high pulse energy dusting in enhancing stone removal during surgery, potentially reducing operative time. Further validation through larger-scale studies is needed to solidify these findings. This technique presents a promising solution, particularly in regions with limited resources where acquiring expensive laser equipment is challenging.

Seguridad, consejos y límites para el uso del láser en la cirugía retrógrada intrarrenal / Laser safety, warnings, and limits in retrograde intrarenal surgery

Objetivo Analizar la información actual sobre la seguridad del láser en la cirugía retrógrada intrarrenal (CRIR), centrándonos en las dos principales tecnologías láser que utilizamos en urología, el láser de holmio:itrio-aluminio-granate (Ho:YAG) y el láser de fibra de tulio (TFL). Métodos Revisión narrativa de los artículos más relevantes publicados en las bases de datos Medline y Scopus sobre este tema. Resultados Los láseres TFL y Ho:YAG con ajustes similares (0,2 J/40 Hz) tienen un aumento de temperatura promedio por volumen similar y la tasa de calentamiento promedio aumenta proporcionalmente a la potencia del láser, especialmente cuando se utilizan frecuencias altas. Datos preclínicos recientes que comparan ambas tecnologías láser con diferentes ajustes del láser coinciden en que cuando la energía suministrada aumenta a expensas de frecuencias más altas, el daño térmico también aumenta. Las frecuencias más altas, a pesar del aumento de temperatura en el medio de irrigación, pueden causar lesiones térmicas accidentales por láser. Conclusiones El uso de ajustes de baja frecuencia y una irrigación adecuada es fundamental para evitar lesiones térmicas en la litotricia endoscópica con láser (LEL). Además, se recomienda el uso de gafas de seguridad láser en la LEL con Ho:YAG y TFL. (AU)

Objective To analyze the current information about laser safety in retrograde intrarenal surgery (RIRS), focusing on the two main laser technologies that we use in urology, the holmium:yttrium-aluminum-garnet (Ho:YAG) laser, and the thulium fiber laser (TFL). Methods Narrative overview of the most relevant articles published in Medline and Scopus databases about this subject. Results TFL and Ho:YAG laser at similar settings (0.2 J/40 Hz) have similar volume-averaged temperature increase and the average heating rate increase proportionally to laser power, especially when high frequencies are used. Recent preclinical data, comparing both laser technologies at different laser settings, agreed that when the delivered energy increases in expenses of higher frequencies, the thermal damage increases too. Higher frequencies, despite of the rise of temperature in the irrigation medium, can cause accidental thermal lasering lesions. Conclusions The use of low frequency settings and a proper irrigation is critical to avoid thermal injury in endoscopic laser lithotripsy (ELL). In addition, the use of laser safety eyeglasses is recommended in Ho:YAG and TFL ELL. (AU)

Comparison of Thulium Fiber Laser versus Holmium laser in ureteroscopic lithotripsy: a Meta-analysis and systematic review.

OBJECTIVES: To compare the efficacy and safety of thulium fiber laser (TFL) to holmium: YAG (Ho: YAG) laser in ureteroscopic lithotripsy for urolithiasis. METHODS: PubMed, Web of Science, Embase, CENTRAL, SinoMed, CNKI database, VIP and Wanfang Database were systematically searched for all relevant clinical trials until September 2023. References were explored to identify the relevant articles. Meta-analysis was carried out for the retrieved studies using RevMan5.4.1 software, and the risk ratio, mean difference and 95% confidence interval were expressed. Statistical significance was set at p < 0.05. The main outcomes of this meta-analysis were stone-free rate (SFR), perioperative outcomes and intraoperative or postoperative complications. RESULTS: Thirteen studies, including 1394 patients, were included. According to the results of pooled analysis, TFL was associated with significantly higher stone-free rate (SFR) [0.52, 95% CI (0.32, 0.85), P = 0.009], shorter operation time [-5.47, 95% CI (-8.86, -2.08), P = 0.002], and less stone migration [0.17, 95% CI (0.06, 0.50), P = 0.001]. However, there was no significant difference in terms of the laser time, duration of hospital stay, drop of hemoglobin level, total energy, postoperative ureteral stenting, the incidence of intraoperative complications or postoperative complications between TFL and Ho: YAGs. CONCLUSION: The findings of this study demonstrated several advantages of TFL in terms of higher SFR, shorter operative time and less stone migration. TRIAL REGISTRATION: The protocol of this systematic review was listed in PROSPERO ( www.crd.york.ac.uk/PROSPERO ) (Protocol number: CRD42022362550).

Laser safety, warnings, and limits in retrograde intrarenal surgery.

OBJECTIVE: To analyze the current information about laser safety in retrograde intrarenal surgery (RIRS), focusing on the two main laser technologies that we use in urology, the holmium:yttrium-aluminum-garnet (Ho:YAG) laser, and the thulium fiber laser (TFL). METHODS: Narrative overview of the most relevant articles published in MEDLINE and Scopus databases about this subject. RESULTS: TFL and Ho:YAG laser at similar settings (0.2 J/40 Hz) have similar volume-averaged temperature increase and the average heating rate increase proportionally to laser power, especially when high frequencies are used. Recent preclinical data, comparing both laser technologies at different laser settings, agreed that when the delivered energy increases in expenses of higher frequencies, the thermal damage increases too. Higher frequencies, despite of the rise of temperature in the irrigation medium, can cause accidental thermal lasering lesions. CONCLUSION: The use of low frequency settings and a proper irrigation is critical to avoid thermal injury in endoscopic laser lithotripsy. In addition, the use of laser safety eyeglasses is recommended in Ho:YAG and TFL ELL.

Analysis of lithotripsy efficiency and stone retropulsion displacement according to pulse characteristics of Ho: YAG laser with Moses effect.

BACKGROUND AND OBJECTIVES: Compared to the conventional Ho: YAG laser, a Ho: YAG laser device has been reported that has a Moses effect to reduce stone retropulsion and increase lithotripsy efficiency. The principle of this equipment is to convert a single laser pulse into two pulses. Most studies on such lasers are limited to lithotripsy efficiency and the prevention of stone retropulsion; studies according to each pulse condition have not been performed. Therefore, the purpose of this study was to quantify the bubble shape, lithotripsy efficiency, and stone retropulsion displacement in a ureteral phantom according to the modulation of the first pulse characteristics of the Moses effect laser under conditions that maintained the total energy and repetition rate. MATERIAL AND METHODS: In this study, a Ho: YAG laser system (Holinwon Pro, Wontech Inc., Korea) with an emission wavelength of 2.10 µm and a Moses effect was used. To verify the Moses effect based on the changes in the pulse, a water tank was fabricated, and the ureteral phantom was manufactured in a structure that could be easily installed in the water tank. Additionally, a spherical artificial stone in the ureteral phantom was prepared by mixing calcined gypsum (Cacinated Gypsum) and water at a ratio of 3:1. In the ureteral phantom, a high-speed camera (FASTCAM NOVA S12, Photron Inc.) and visible light were used to record pulse-dependent image analysis of bubbles and stone retropulsion. RESULT: After mounting the artificial stone in the ureteral phantom, the pulse duration and energy of the first pulse of the Moses effect laser were varied; 30 laser shots for 3 s at a repetition rate of 10 Hz were applied to quantify the lithotripsy efficiency and stone retropulsion displacement, and the experimental values were compared. The fragmentation efficiency was confirmed by measuring the mass before and after the laser pulse application, the original position of the stone retropulsion displacement, and the distance moved. The minimum value of stone retropulsion displacement appeared when the pulse duration of the first pulse was 300 µs, the pulse energy was 100 mJ, and the value was approximately 0.28 mm. The highest fragmentation efficiency was observed under the same conditions, and the mass loss of the artificial stone at that time was approximately 3.7 mg. CONCLUSION: Quantitative indices, such as lithotripsy efficiency and stone retropulsion displacement, were confirmed using ultrahigh-speed cameras to determine the effect of the first pulse energy and duration of the Ho: YAG laser with the Moses effect on stone removal. It was confirmed that the longer the duration of the primary pulse and the lower the energy, the higher the fragmentation efficiency. In this study, the possibility of manufacturing a laser with an optimal stone-removal effect was confirmed according to the first-pulse condition of the laser with the Moses effect.

Benefits of accurate and guided endoureterotomy versus ureteral balloon dilatation in the management of ureteral strictures-comparative animal study.

Background: Endoscopic treatment of ureteral strictures provides a minimally invasive approach with a shorter hospital stay and less postoperative pain. There are different therapeutic options, the dilatation balloon and endoureterotomy with holmium yttrium-aluminum-garnet (Ho:YAG) laser are the most used. To assess histological changes after endoureterotomy in the ureteral stricture treatment comparing Ho:YAG laser endoureterotomy versus balloon dilatation endoureterotomy. Methods: The subjects used were a total of 48 female pigs. The initial assessment consisted of an endoscopic, nephrosonographic, and contrast fluoroscopic evaluation of the urinary tract. Subsequently, a model of ureteral stricture was performed. Three weeks later, the ureteral stricture was diagnosed and treated. Then animals were randomly assigned to two groups (group A, Balloon dilatation endoureterotomy and group B, Holmium laser retrograde endoureterotomy) in which a double-pigtail ureteral stent was placed for 3 weeks. Follow-up assessments were performed at 3-6 weeks. The final follow-up was completed at 5 months and included the pathological study. Results: In terms of therapeutic effectiveness, the overall success was 81.2%. The success rate was 91.7% in group B and 70.8%in group A without statistical significance. No evidence of vesicoureteral reflux nor urinary tract anomalies were observed. Histological assessment showed statistical significance in overall score, lamina propria fibrosis and serosal alterations in group A with higher histological changes. Conclusions: The overall histopathological score after ureteral stricture treatment in an animal model showed better remodeling of incised ureteral wall healing after Ho:YAG laser endoureterotomy. Laser endoureterotomy tends to have higher success rate compared to balloon dilatation.

Thulium fiber laser vs Ho:YAG in RIRS: a prospective randomized clinical trial assessing the efficacy of lasers and different fiber diameters (150 µm and 200 µm).

INTRODUCTION: The aims of the study: (1) to compare the Super Pulse Thulium Fiber Laser (SP TFL) and the holmium: yttrium-aluminium-garnet (Ho:YAG) lasers in retrograde intrarenal surgery (RIRS); (2) to compare the efficacy of SP TFL laser fibers of different diameters (150 µm and 200 µm). METHODS: A prospective randomized single-blinded trial was conducted. Patients with stones from 10 to 20 mm were randomly assigned RIRS in three groups: (1) SP TFL (NTO IRE-Polus, Russia) with fiber diameter of 150 µm; (2) SP TFL with 200-µm fiber; and (3) Ho:YAG (Lumenis, USA) with 200-µm fiber. RESULTS: Ninety-six patients with kidney stones were randomized to undergo RIRS with SP TFL using a 150-µm fiber (34 patients) and a 200-µm fiber (32 patients) and RIRS with Ho:YAG (30 patients). The median laser on time (LOT) in the 200-µm SP TFL group was 9.2 (6.2-14.6) min, in 150-µm SP TFL-11.4 (7.7-14.9) min (p = 0.390), in Ho:YAG-14.1 (10.8-18.1) min (p = 0.021). The total energy consumed in 200-µm SP TFL was 8.4 (5.8-15.2) kJ; 150-µm SP TFL - 10.8 (7.3-13.5) kJ (p = 0.626) and in Ho:YAG-15.2 (11.1-25.3) kJ (p = 0.005). CONCLUSIONS: Irrespective of the density, RIRS with SP TFL laser has proven to be both a safe and effective procedure. Whilst the introduction of smaller fibers may have the potential to reduce the duration of surgery, SP TFL results in a reduction in the LOT and total energy for stone ablation in RIRS compared with Ho:YAG.

Trans sacral Endoscopic laser Decompression- a case report, technical note and literature review.

Introduction: The concept of sacral epiduroscopic laser decompression (SELD) is based on the introduction of a steerable catheter in the sacral hiatus followed by the insertion of a fiberoptic laser system into the ventral side of the epidural disc space with an epiduroscope. This procedure enables the direct decompression of the ruptured annulus as the laser vaporizes the bulging disc in the herniated part, cauterization of the sinuvertebral nerve, adhesiolysis of structures nearby the nerve root, and irrigation of inflammation with saline and steroids. Case Report: A 44-year-old man presented to the outpatient department with a 12-month history of low back pain. His back pain had increased progressively. At the time of presentation, his back pain VAS score was 7/10 and his ODI score was 44. He had received non-steroidal anti-inflammatories for more than 6 months and an epidural injection elsewhere with minimal relief from symptoms. On physical examination, power in the lower limbs was 5/5 as per the MRC grading, and deep tendon reflexes were normal. Conclusion: The procedure is a useful technique in treating lumbar disc herniation with rapid pain relief and improvements in functional outcomes without any injury to paraspinal muscles or any resection of the ligaments and bony structures. SELD is safe, precise, and effective in the treatment of symptomatic lumbar lesions. Improvements in the optics and visuals with advancements in lasers' ability to ablate tissue could be beneficial. Large, randomized, and multicenter trials are needed to further explore the potential of SELD.

Comparison of three techniques in bladder stone surgery: Which technique is more effective and safe?

Background: In our study, we aimed to compare the success and complication rates of percutaneous cystolithotripsy (PCCL), transurethral cystolithotripsy (TUCL), and Ho: YAG laser lithotripsy in the surgery of bladder stones that occurred due to various reasons. Patients and Methods: Patients diagnosed with single or multiple bladder stones with long axis larger than 2 cm, resulting for various reasons, were included in ou study. Sizes of the stones, cystolithotripsy and discharge times, catheter removal times, complications observed, and the visual pain scale (VPS) were retrospectively evaluated separately from the surgical techniques implemented for accompanying patients and their data. Results: TUCL (group 1) was implemented in 40, PCCL (group 2) was implemented in 44, and transurethral Ho: YAG laser lithotripsy (group 3) was implemented in 30 of the 121 patients included in the study. The bladder stone long axe group 1 average was 3,7 cm (2,2-5,3), group 2 average was 3,74 cm (2,1-5,1), and group 3 average was 3,7 cm (2,3-4,7). Urethral stricture evolved in two patients who underwent TUCL. A statistically significant difference was observed on behalf of PCCL in terms of operation time. There was significance in the Ho: YAG laser cystolithotripsy group in comparison with VPS scores. No significant differences were found in terms of age, stone size, urethral catheter removal times, and discharge times. The average follow-up time was 6 months. Conclusion: Although all three methods were quite successful in bladder stone surgery, average cystolithotripsy times were significantly low in the PCCL technique. Thinking that the most common cause of bladder stone is BPH, it is stated that the suprapubic inserted tube ease the bladder drainage during transurethral resection of the prostate (TUR-P). In this way, the duration of the most common accompanying surgeries is shortened and performed more safely.

Dusting efficacy between the regular setting of holmium laser (Ho:YAG) versus Vapor Tunnel pulse modality for non-complex kidney stones.

The new pulse modality Vapor-Tunnel™ (VT) consists of a very long pulse that uses the minimum peak power, causing the energy to pass through a previously created vapor channel or tunnel. The first part of the pulse creates a vapor channel, whereas the remaining energy is discharged immediately after, passing straight through the previously created tunnel. The aim of this study is to compare the dusting efficacy between Ho:YAG laser with long pulse and Ho:YAG laser with VT for non-complex kidney stones. A retrospective comparative study of 236 patients who underwent retrograde intrarenal surgery using Ho:YAG laser (long pulse vs. VT) was performed. Stone size, stone density, laser settings, laser emission time, and total operative time were recorded. We also assessed the lithotripsy efficacy (J/mm3). The stone-free rate was defined as the absence of stone fragments in a non-contrast abdominal computed tomography 4 weeks after the procedure. A total of 118 patients were included in each group. There was no significant difference in age, gender, and body mass index. Median stone volume (737 mm3 vs. 636 mm3) and stone density (788 HU vs. 656 HU) were higher in the VT group. Total energy used (14.5 J vs. 18.2 J), the laser emission time (20 min vs. 26 min), and the total operative time (79.5 min vs. 95 min) were significantly lower in the VT group. The stone-free rate was comparable between both groups (74.5% for VT and 66.1% for the long-pulse group, p = 0.15). When we evaluated the efficacy of laser lithotripsy, a significantly lower difference was obtained in the VT group (median 12.5 J/mm3 vs. median 23.1 J/mm3). The VT pulse modality was associated with decreased laser time and operative time. Additionally, it increased lithotripsy efficacy compared to Ho:YAG long pulse laser, but with a comparable free-stone rate.

The predictive factors that total laser energy consumed during retrograde intrarenal surgery (RIRS): stone area and density.

Holmium: YAG (Ho: YAG) laser lithotripsy with flexible ureterorenoscopy can be used with high stone-free and low complication rates for renal stones. This study aimed to determine the factors affecting the total laser energy in cases with provided stone-free status after a single session of retrograde intrarenal surgery (RIRS). Data of 222 patients who underwent RIRS between October 2017 and March 2020 were evaluated retrospectively. After exclusion criteria, the study was carried out with 184 stone-free cases. All cases were performed without using a ureteral access sheath (UAS), and dusting was preferred as the lithotripsy method. The effects of age, gender, body mass index (BMI), previous RIRS history, previous shock wave lithotripsy (SWL) history, stone localization, number of stones, stone surface area, and stone density on total laser energy were analyzed. There was no significant correlation between total laser energy with gender, BMI, previous RIRS history, previous SWL history, stone localization, and the number of stones (p:0.347, p:0.482, p:0.119, p:0.167, p:0.907, p:0.933 respectively). There was a significant correlation between age and total laser energy (p = 0.032), but it was not observed when the effect of the stone surface area was removed (p = 0.354). There were significant correlations between total laser energy and stone surface area, stone density, and total laser time (p<0.001, p<0.001, and p <0.001, respectively). Stone area and stone density affect the total energy consumed during laser lithotripsy. Urologists should consider the stone area, stone density, and the power of the laser device to determine which surgical technic to prefer.

Temperature changes of renal calyx during high-power flexible ureteroscopic Moses holmium laser lithotripsy: a case analysis study.

PURPOSE: The risk of thermal damage increases with the introduction of high-power lasers during holmium laser lithotripsy. This study aimed to quantitatively evaluate the temperature change of renal calyx in the human body and the 3D printed model during high-power flexible ureteroscopic holmium laser lithotripsy and map out the temperature curve. METHODS: The temperature was continuously measured by a medical temperature sensor secured to a flexible ureteroscope. Between December 2021 and December 2022, willing patients with kidney stones undergoing flexible ureteroscopic holmium laser lithotripsy were enrolled. High frequency and high-power settings (24 W, 80 Hz/0.3 J and 32 W, 80 Hz/0.4 J) were performed for each patient with room temperature (25 °C) irrigation. In the 3D printed model, we studied more holmium laser settings (24 W, 80 Hz/0.3 J, 32 W, 80 Hz/0.4 J and 40 W, 80 Hz/0.4 J) with warmed (37 °C) and room temperature (25 °C) irrigation. RESULTS: Twenty-two patients were enrolled in our study. With 30 ml/min or 60 ml/min irrigation, the local temperature of the renal calyx did not reach 43 °C in any patient under 25 °C irrigation after 60 s laser activation. There were similar temperature changes in the 3D printed model with the human body under the irrigation of 25 °C. Under the irrigation of 37 °C, the temperature rise slowed down, but the temperature in the renal calyces was close to or even exceeded the 43 °C at the setting of 32 W, 30 ml/min and 40 W, 30 ml/min after continuing laser activation. CONCLUSION: In the irrigation of 60 ml/min, the temperature in the renal calyces can still be maintained within a safe range after continuous activation of a holmium laser up to 40 W. However, continuous activation of 32 W or higher power holmium laser in the renal calyces for more than 60 s in the limited irrigation of 30 ml/min can cause excessive local temperature, in such situation room temperature perfusion at 25 ℃ may be a relatively safer option.

Assessment of intrarenal temperature dynamics when using holmium and thulium: YAG lasers in an ex vivo porcine kidney model.

AIM: To measure the temperature dynamics at the renal surface and within the urinary tract when using Ho:YAG and Tm:YAG lasers for tissue ablation. MATERIALS AND METHODS: Porcine kidneys were used. Both types of lasers with different configurations and fiber sizes were used through a flexible ureteroscope. The temperature at the renal surface was recorded using a thermal camera while the intrarenal temperature was measured using two thermal probes, the first one at the ureteropelvic junction and the second one at the calyx used for lasering. Temperature was determined at 0.5-1-3-5 and 10 min. RESULTS: Recordings at the ureteropelvic junction and calyx revealed significant increases when using Tm:YAG with the 273 µm (10 W to 50 W) (p ≤ 0.02) and 550 µm (10 W) fiber (p = 0.04). With Ho:YAG there was a significant increase when using 273 µm (at 10 W and 20 W) (p ≤ 0.03) and 365 µm (10 W) fibers (p = 0.04). Regarding fiber size there was a significant difference when using Tm:YAG (at 20 W and 40 W) (p < 0.05). The thermal camera recorded a mean increase of 8 °C in the UPJ while the remaining areas of the kidney did not undergo significant changes. CONCLUSIONS: Temperature changes were greater when using the Ho:YAG laser with respect to Tm:YAG at similar power settings for tissue ablation. The greatest temperature increase was recorded at the UPJ from where the heat dissipated throughout the kidney.

Evaluación de la dinámica de la temperatura intrarrenal con el uso de láseres holmio y tulio YAG en un modelo exvivo de riñón porcino / Assessment of intrarenal temperature dynamics when using holmium and thulium: YAG lasers in an ex vivo porcine kidney model

Objetivo Medir la dinámica de la temperatura en la superficie renal y dentro de la vía urinaria al usar los láseres Ho:YAG y Tm:YAG para la ablación tisular. Materiales y métodos Se utilizaron riñones porcinos. Ambos tipos de láseres con diferentes configuraciones y tamaños de fibras se usaron a través de un ureteroscopio flexible. La temperatura en la superficie renal fue registrada mediante una cámara termográfica mientras que la intrarrenal fue medida a través de dos termómetros, el primero en la unión pieloureteral y el segundo en el cáliz elegido para el uso del láser. La temperatura fue determinada a los 0,5-1-3-5 y 10 minutos. Resultado Los registros en la unión pieloureteral y en el cáliz revelaron incrementos significativos al usar el Tm:YAG con la fibra de 273μm (10W a 50W) (p≤0,02) y de 550μm (10W) (p=0,04). Con el Ho:YAG se registró un incremento significativo al usar fibras de 273μm (a 10W y 20W) (p≤0,03) y de 365μm (10W) (p=0,04). Respecto al tamaño de las fibras, hubo una diferencia significativa al usar el Tm:YAG (a 20W y 40W) (p<0,05). La cámara termográfica registró un incremento medio de 8°C en la unión pieloureteral mientras que el resto del riñón no sufrió cambios significativos. Conclusione Los cambios de temperatura fueron mayores al usar el láser Ho:YAG respecto al Tm:YAG a configuraciones de poder similares para la ablación tisular. El mayor incremento de temperatura fue registrado en la unión pieloureteral desde donde el calor se disipaba al resto del riñón (AU)

Aim To measure the temperature dynamics at the renal surface and within the urinary tract when using Ho:YAG and Tm:YAG lasers for tissue ablation. Materials and methods Porcine kidneys were used. Both types of lasers with different configurations and fiber sizes were used through a flexible ureteroscope. The temperature at the renal surface was recorded using a thermal camera while the intrarenal temperature was measured using two thermal probes, the first one at the ureteropelvic junction and the second one at the calyx used for lasering. Temperature was determined at 0.5-1-3-5 and 10minutes. Results Recordings at the ureteropelvic junction and calyx revealed significant increases when using Tm:YAG with the 273μm (10W to 50W) (p≤0.02) and 550μm (10W) fiber (p=0.04). With Ho:YAG there was a significant increase when using 273μm (at 10W and 20W) (p≤0.03) and 365μm (10W) fibers (p=0.04). Regarding fiber size there was a significant difference when using Tm:YAG (at 20W and 40W) (p<0.05). The thermal camera recorded a mean increase of 8°C in the UPJ while the remaining areas of the kidney did not undergo significant changes. Conclusions Temperature changes were greater when using the Ho:YAG laser with respect to Tm:YAG at similar power settings for tissue ablation. The greatest temperature increase was recorded at the UPJ from where the heat dissipated throughout the kidney (AU)

Cut-to-the-light technique is useful for complete obstruction of a Wallace ureteroileal anastomosis.

Introduction: Obstruction of a ureteroileal anastomosis after urinary diversion is an unpleasant situation for patients and clinicians alike. Case presentation: A 48-year-old man who underwent a radical cystectomy for muscle-invasive bladder cancer and urinary diversion using the Wallace technique complained of right back pain. Computed tomography showed right hydronephrosis. Cystoscopy via the ileal conduit revealed complete obstruction of the ureteroileal anastomosis. We performed a bilateral approach (antegrade and retrograde) to use the cut-to-the-light technique. A guidewire and 7Fr single J catheter could be inserted. Conclusion: The cut-to-the-light technique was useful for complete obstruction of the ureteroileal anastomosis, the length of which was <1 cm. Herein, we report on the cut-to-the-light technique with a literature review.

Temperature profiles during ureteroscopy with thulium fiber laser and holmium:YAG laser: Findings from a pre-clinical study.

OBJECTIVE: The aim of this study was to investigate temperature profiles in both the renal pelvis and parenchyma during Thulium Fiber Laser (TFL) and Holmium:yttrium-aluminium-garnet (Ho:YAG) laser activation in an ex-vivo porcine model. METHODS: Three porcine kidneys with intact renal pelvis and proximal ureters were used in the study. A temperature sensor was inserted through a nephrostomy tube into the renal pelvis and a second sensor was inserted directly into the renal parenchyma. Temperatures were recorded during continuous laser activation for 180 s, and for an additional 60 s after deactivation. TFL (150 µm and 200 µm) and Ho:YAG (270 µm) laser delivered power at settings of 2.4 W, 8 W, 20 W and 30 W. RESULTS: Intrapelvic temperatures correlated directly to power settings. Higher power produced higher temperatures. For example, using a 150 µm fiber at 2.4 W resulted in a 2.6 °C rise from baseline (p = 0.008), whereas using the same fiber at 20 W produced a rise in temperature of 19.9 °C (p = 0.02). Larger laser fibers caused significantly higher temperatures compared to smaller fibers using equivalent power settings, e.g. mean temperature at 20 W using 150 µm was 39.6 °C compared to 44.9 °C using 200 µm, p < 0.001. There was a significant increase in parenchymal temperatures when applying 20 W and 30 W of laser power with the two larger fibers. CONCLUSION: In this ex-vivo study, renal temperatures correlated directly to power settings. Higher power produced higher temperatures. Furthermore, larger laser fibers caused higher temperatures. These findings could help guide selection of safe power settings for ureteroscopic lithotripsy, but future clinical studies are needed for confirmation.