A comparison between vapor tunnel and virtual basket for the treatment of proximal ureteral stones using holmium:YAG laser (Cyber Ho): which is the best tool to reduce retropulsion?

PURPOSE: To compare vapor tunnel (VT) and virtual basket (VB) tools to reduce retropulsion in the treatment of proximal ureteral stones. METHODS: Patients with a single proximal ureteral stone were randomly assigned to holmium laser lithotripsy with the use of VT (Group A) or VB (Group B) tool. The 150W holmium:YAG cyber Ho generator was used. We compared operative time, dusting time, need for flexible ureteroscopy due to stone push-up and occurrence of ureteral lesions. The stone-free rate (SFR) and the occurrence of postoperative ureteral strictures were assessed. RESULTS: 186 patients were treated, of which 92 with the VT (49.5%, Group A) and 94 with the VB (50.5%, Group B). Mean stone size was 0.92 vs. 0.91 cm in Groups A vs. B (p = 0.32). Mean total operative time and dusting time were comparable between groups. 7 (7.6%) vs. 6 (6.4%) patients in Groups A vs. B required a flexible ureteroscope because of stone push-up (p = 0.12). Ureteral mucosa lesions were observed in 15 (16.3%) vs. 18 (19.1%) cases in the VT vs. VB group (p = 0.09). 1-Month SFR was comparable (97.8% vs. 95.7%, p = 0.41). We observed one case (1.1%) of postoperative ureteral stricture in the VT group vs. two cases (2.1%) in the VB group (p = 0.19). CONCLUSIONS: VT and VB are equally safe and effective tools in reducing retropulsion of ureteral stones. Operative time, dusting time and SFR were comparable. They also equally avoided stone push-up and prevented ureteral lesions, which may later occur in ureteral strictures.

How I Do It: Teaching holmium laser enucleation of the prostate (HoLEP).

Holmium laser enucleation of the prostate (HoLEP) is considered a size-independent technique to treat benign prostatic hyperplasia. This safe and effective procedure is increasingly being adopted in urology training programs worldwide, yet limited teaching strategies have been described. Endoscopic handling during HoLEP allows for a simultaneous interaction between the surgeon and trainee, facilitating a guided teaching strategy with increasing difficulty as experience grows. In this article, we describe our stepwise approach for teaching HoLEP as part of a structured surgical training curriculum. We also evaluate the association of our method with intraoperative efficiency parameters and immediate postoperative surgical outcomes of 200 HoLEP procedures.

A proposed mathematical model to help preoperative planning between RIRS and MiniPerc for renal stones between 10 and 20 mm using holmium:Yag laser (Cyber Ho): the stone management according to size-hardness (SMASH) score.

To evaluate the performance of a mathematical model to drive preoperative planning between RIRS and MiniPerc (MP) for the treatment of renal stones between 10 and 20 mm. Patients with a renal stone between 10 and 20 mm were enrolled. A mathematical model named Stone Management According to Size-Hardness (SMASH) score was calculated: hounsfield units (HU) χ stone maximum size (cm)/100. Patients were divided into 4 groups: RIRS with score < 15 (Group A), RIRS with score ≥ 15 (Group B), MP with score < 15 (Group C), MP with score ≥ 15 (Group D). Cyber Ho device was always used. Stone free rate (SFR) was assessed after 3 months. Complication rate and need for auxiliary procedures were evaluated. Between January 2019 and December 2021, 350 patients were enrolled (87, 88, 82 and 93 in Groups A, B, C and D). Mean stone size was 13.1 vs 13.3 mm in Group A vs B (p = 0.18) and 16.2 vs 18.1 mm in Group C vs D (p = 0.12). SFR was 82%, 61%, 75% and 85% for Groups A, B, C and D. SFR was comparable between Groups C and D (p = 0.32) and Groups A and C (p = 0.22). SFR was significantly higher in Group A over B (p = 0.03) and in Group D over B (p = 0.02). Complication rate was 2.2%, 3.4%, 12.1%, 12.9% for Groups A, B, C, D. RIRS and MP are both safe and effective. The mathematical model with the proposed cut-off allowed a proper allocation of patients between endoscopic and percutaneous approaches.Registration number of the study ISRCTN55546280.

Is "Kidney Stone Calculator" efficient in predicting ureteroscopic lithotripsy duration? A holmium:YAG and thulium fiber lasers comparative analysis.

PURPOSE: This study aimed to evaluate the ability of Kidney Stone Calculator (KSC), a flexible ureteroscopy surgical planning software, to predict the lithotripsy duration with both holmium:YAG (Ho:YAG) and thulium fiber laser (TFL). METHODS: A multicenter prospective study was conducted from January 2020 to April 2023. Patients with kidney or ureteral stones confirmed at non-contrast computed tomography and treated by flexible ureteroscopy with laser lithotripsy were enrolled. "Kidney Stone Calculator" provided stone volume and subsequent lithotripsy duration estimation using three-dimensional segmentation of the stone on computed tomography and the graphical user interface for laser settings. The primary endpoint was the quantitative and qualitative comparison between estimated and effective lithotripsy durations. Secondary endpoints included subgroup analysis (Ho:YAG-TFL) of differences between estimated and effective lithotripsy durations and intraoperative outcomes. Multivariate analysis assessed the association between pre- and intraoperative variables and these differences according to laser source. RESULTS: 89 patients were included in this study, 43 and 46 in Ho:YAG and TFL groups, respectively. No significant difference was found between estimated and effective lithotripsy durations (27.37 vs 28.36 min, p = 0.43) with a significant correlation (r = + 0.89, p < 0.001). Among groups, this difference did not differ (p = 0.68 and 0.07, respectively), with a higher correlation between estimated and effective lithotripsy durations for TFL compared to Ho:YAG (r = + 0.95, p < 0.001 vs r = + 0.81, p < 0.001, respectively). At multivariate analysis, the difference was correlated with preoperative (volume > 2000 mm3 (Ho:YAG), 500-750 mm3 SV and calyceal diverticulum (TFL)), operative (fragmentation setting (p > 0.001), and basket utilization (p = 0.05) (Ho:YAG)) variables. CONCLUSION: KSC is a reliable tool for predicting the lithotripsy duration estimation during flexible ureteroscopy for both Ho:YAG and TFL. However, some variables not including laser source may lead to underestimating this estimation.

Analyzing global research trends and focal points in the utilization of laser techniques for the treatment of urolithiasis from 1978 to 2022: visualization and bibliometric analysis.

Laser lithotripsy is gaining global prominence and is a dynamically progressing field marked by a continual influx of new and comprehensive research each year. Recently, there has been a noticeable shift toward the adoption of various kinds of lasers, such as holmium: yttrium-aluminum-garnet (Ho:YAG) and thulium fiber (TFL) lasers. Consequently, we aim to conduct a bibliometric analysis to analyze key areas of research activity within scientific publications that center on the utilization of laser techniques in urolithiasis. A search of the literature spanning from 1978 to 2022 was carried out on 25 December 2023 using the Scopus database to explore research related to the application of laser techniques for urolithiasis treatment. Visualization analysis was performed using VOSviewer software (version 1.6.20). We examined 962 publications that met the specified criteria, 791 (82.22%) of which were original articles. The analysis of the retrieved publications indicated a consistent increase in research output from 1978 to 2022; a particularly noteworthy surge occurred after 2003. In particular, the U.S. claimed the leading position as the most productive country, contributing 211 articles (21.93%). However, India had the highest research productivity according to the adjustment index of 19.08. In the European region, 324 publications (33.68% of the total) originated from 25 countries. The Journal of Endourology contributed the most between 1978 and 2022 (n = 96, 9.98%). The most cited paper examined the effectiveness of holmium: yttrium-aluminum-garnet (Ho:YAG) lasers, while a subsequent study focused on the use of a thulium fiber laser (TFL), an emerging laser technology that has gained increased recognition. Co-occurrence analysis revealed three distinct clusters focusing on the types of laser technology, minimally invasive approaches, and success rate/postoperative complications. This comprehensive investigation delves into the global landscape of laser use for the treatment of urolithiasis. This review supports the emerging clinical concept of using various types of laser technology for urolithiasis treatment. Moreover, the hot issues that researchers should focus on based on the findings of this study are the use of different types of laser lithotripsy in view of the surgical approach, success rate and complications.

Effects of Thermal Insulation on Recovery and Comfort of Patients Undergoing Holmium Laser Lithotripsy.

BACKGROUND Patients with urolithiasis often undergo transurethral ureteroscopic holmium laser lithotripsy, a procedure that can be affected by perioperative thermal management. This study examines the impact of compound thermal insulation management on patient recovery and comfort during transurethral ureteroscopic holmium laser lithotripsy. MATERIAL AND METHODS In this study, 551 patients who underwent transurethral ureteroscopic holmium laser lithotripsy from April 2019 to December 2022 were randomly assigned to either an observation group (n=276) or control group (n=275). Both groups received routine surgical care, with the observation group additionally receiving compound thermal insulation management. We recorded and compared perioperative body temperature changes, anesthetic resuscitation indicators (bispectral index recovery time, extubation time, fully awake time, Postanesthesia Care Unit retention time), comfort level (General Comfort Questionnaire), and quality of life (Nottingham Health Profile). We also compared the incidence of complications. RESULTS There was no significant difference in body temperature between groups at the start surgery. However, the observation group showed significantly higher temperatures during and at the end of surgery. Anesthetic resuscitation indicators were significantly better in the observation group. Both groups showed improved comfort and quality of life after surgery, with more significant improvements in the observation group. The observation group also had a lower incidence of complications, such as hypothermia and rigor. CONCLUSIONS Compound thermal insulation management during transurethral ureteroscopic holmium laser lithotripsy improved perioperative temperature maintenance, accelerated postoperative recovery, reduced complication rates, and enhanced patient comfort and quality of life.

Revisiting the issue of "beach balls" in holmium laser enucleation of prostate: clinical and histological characterization.

PURPOSE: To clinically and histologically characterize prostatic nodules resistant to morcellation ("beach balls," BBs). PATIENTS AND METHODS: We reviewed a consecutive cohort of 559 holmium laser enucleation of the prostate (HoLEP) procedures performed between January 2020 and November 2023. The BBs group comprised 55 men (10%) and the control group comprised 504 men (90%). The clinical, intraoperative, outcome, and histologic data were statistically processed for the prediction of the presence of BBs and their influence on the perioperative course and outcome. RESULTS: The BBs group in comparison to the controls was older (75 vs 73 years, respectively, p = 0.009) and had higher rates of chronic retention (51 vs 29%, p = 0.001), larger prostates on preoperative abdominal ultrasound (AUS) (140 vs 80 cc, p = 0.006E-16), longer operating time (120 vs 80 min, p = 0.001), higher weights of removed tissue (101 vs 60 gr, p = 0.008E-10), higher complication rates (5 vs 1%, p = 0.03), and longer hospitalization (p = 0.014). A multivariate analysis revealed that larger prostates on preoperative AUS and older age independently predicted the presence of BBs which would prolong operating time. ROC analyses revealed that a threshold of 103 cc on AUS predicted BBs with 94% sensitivity and 84% specificity. BBs were mostly characterized histologically by stromal component (p = 0.005). CONCLUSIONS: BBs are expected in older patients and cases of chronic retention. Prostatic volume is the most reliable predictor of their presence. They contribute to prolonged operating time and increased risk of complications. The predominantly stromal composition of the BBs apparently confers their resistance to morcellation.

Getting hot in here! Comparison of Holmium vs. thulium laser in an anatomic hydrogel kidney model.

As laser technology has advanced, high-power lasers have become increasingly common. The Holmium: yttrium-aluminum-garnet (Ho:YAG) laser has long been accepted as the standard for laser lithotripsy. The thulium fiber laser (TFL) has recently been established as a viable option. The aim of this study is to evaluate thermal dose and temperature for the Ho:YAG laser to the TFL at four different laser settings while varying energy, frequency, operator duty cycle (ODC). Utilizing high-fidelity, 3D-printed hydrogel models of a pelvicalyceal collecting system (PCS) with a synthetic BegoStone implanted in the renal pelvis, laser lithotripsy was performed with the Ho:YAG laser or TFL. At a standard power (40W) and irrigation (17.9 ml/min), we evaluated four different laser settings with ODC variations with different time-on intervals. Temperature was measured at two separate locations. In general, the TFL yielded greater cumulative thermal doses than the Ho:YAG laser. Thermal dose and temperature were typically greater at the stone when compared away from the stone. Regarding the TFL, there was no general trend if fragmentation or dusting settings yielded greater thermal doses or temperatures. The TFL generated greater temperatures and thermal doses in general than the Ho:YAG laser with Moses technology. Temperatures and thermal doses were greater closer to the laser fiber tip. It is inconclusive as to whether fragmentation or dusting settings elicit greater thermal loads for the TFL. Energy, frequency, ODC, and laser-on time significantly impact thermal loads during ureteroscopic laser lithotripsy, independent of power.

WATTS happening? Evaluation of thermal dose during holmium laser lithotripsy in a high-fidelity anatomic model.

PURPOSE: To evaluate the thermal profiles of the holmium laser at different laser parameters at different locations in an in vitro anatomic pelvicalyceal collecting system (PCS) model. Laser lithotripsy is the cornerstone of treatment for urolithiasis. With the prevalence of high-powered lasers, stone ablation efficiency has become more pronounced. Patient safety remains paramount during surgery. It is well recognized that the heat generated from laser lithotripsy has the potential to cause thermal tissue damage. METHODS: Utilizing high-fidelity, 3D printed hydrogel models of a PCS with a synthetic BegoStone implanted in the renal pelvis, laser lithotripsy was performed with the Moses 2.0 holmium laser. At a standard power (40 W) and irrigation pressure (100 cm H2O), we evaluated operator duty cycle (ODC) variations with different time-on intervals at four different laser settings. Temperature was measured at two separate locations-at the stone and away from the stone. RESULTS: Temperatures were highest closest to the laser tip with a decrease away from the laser. Fluid temperatures increased with longer laser-on times and higher ODCs. Thermal doses were greater with increased ODCs and the threshold for thermal injury was reached for ODCs of 75% and 100%. CONCLUSION: Temperature generation and thermal dose delivered are greatest closer to the tip of the laser fiber and are not dependent on power alone. Significant temperature differences were noted between four laser settings at a standardized power (40 W). Temperatures can be influenced by a variety of factors, such as laser-on time, operator duty cycle, and location in the PCS.

Pulse modulation in En-Bloc HoLEP: does it really matter? A propensity score matched analysis.

INTRODUCTION: Holmium laser enucleation of the prostate (HoLEP) is an established option in the surgical treatment of benign prostatic hyperplasia. Pulse modulation, such as MOSES® technology, has recently been introduced and may offer potential advantages in HoLEP. METHODS: Perioperative data from 117 patients who underwent MOSES® laser enucleation of the prostate (MoLEP) were collected. Propensity score matching using prostate volume, age, body mass index (BMI), and anticoagulant intake was performed using a database of 237 patients treated with HoLEP. In total, 234 patients were included in the analysis. RESULTS: Prostate volume (104 vs. 102 ml), age (70 vs. 71 years), BMI (27 vs. 27), and anticoagulant intake (34 vs. 35%) did not differ significantly between the groups. There were no significant differences in operation time (61.5 vs. 58.1 min, p = 0.42), enucleation efficiency (2.5 vs. 2.6 g/min, p = 0.74), hemostasis time (7.8 vs. 8 min, p = 0.75) and hemoglobin drop (0.9 vs. 0.7 mg/dl, p = 0.48). The complication rates were low in both groups (16.2% for HoLEP and 17.1% for MoLEP). No differences were noted in the Clavien-Dindo Classification (p = 0.63) and the Comprehensive Complication Index (p = 0.24). The rate of complications > CDC IIIa was 0.9% for HoLEP (endoscopic coagulation) and 1.7% for MoLEP (2 cases of endoscopic coagulation). No transfusions were administered. CONCLUSION: Overall, the enucleation efficiency was high in both groups and the procedure time was short. HoLEP is an efficient and safe treatment option in experienced hands, regardless of the use of pulse modulation technology.

Safety Parameters for the Use of Holmium:YAG Laser in the Treatment of Biliary Calculi: The Ex-Vivo Model.

Background and Objectives: While studies have demonstrated the efficacy of cholangioscopy-guided Holmium-Yttrium aluminum garnet (Ho:YAG) laser lithotripsy for the treatment of refractory bile duct stones, data regarding the safety of the operating parameters for laser lithotripsy are lacking. The aim of this study was to determine safe, yet effective, energy settings for Ho:YAG laser in the ex-vivo model. Materials and Methods: This ex vivo experimental study utilized the Ho:YAG laser on porcine bile duct epithelium and human gallstones. Ho:YAG laser lithotripsy was applied in different power settings from 8 to 15 Watts (W) to six explanted porcine bile ducts. Settings that appeared safe were then utilized to fragment seventy-three human gallstones. Results: The median bile duct perforation times with the Ho:YAG laser between 8-15 W were: >60 s (8 W); 23 s (9 W); 29 s (10 W); 27 s (12 W); 12 s (14 W); and 8 s (15 W). Statistically significant differences in the median perforation times were noted between 8 W vs. 15 W, 9 W vs. 15 W, 10 W vs. 15 W, and 12 W vs. 15 W (p < 0.05). When using a 365 µm Ho:YAG laser probe at 8-12 W, the fragmentation rates on various size stones were: 100% (<1.5 cm); 80-100% (1.6-2.0 cm) and 0-32% (>2.0 cm). Optimal fragmentation was seen utilizing 12 W with high energy (2.4 J) and low frequency (5 Hz) settings. Using a larger 550 µm probe at these settings resulted in 100% fragmentation of stones larger than 2 cm. Conclusions: The Ho:YAG laser appears to be safe and effective in the treatment of large bile duct stones when used between 8-12 W in 5 s bursts in an ex vivo model utilizing porcine bile ducts and human gallstones.

Thulium fiber laser vs. holmium laser enucleation of the prostate: results of a prospective randomized non-inferiority trial.

PURPOSE: Holmium laser enucleation of the prostate (HoLEP) represents the current standard procedure for size-independent surgical therapy of benign prostatic obstruction (BPO). With advent of the novel laser technology thulium fiber laser (TFL), we hypothesized that the functional outcome of TFL enucleation of the prostate (ThuFLEP) is non-inferior compared to HoLEP. METHODS: From October 2021 to October 2022, 150 patients with BPO were recruited for the prospective randomized trial in accordance with CONSORT. Stratified randomization into the arms ThuFLEP (n = 74) or HoLEP (n = 76) was carried out. The primary endpoint was non-inferior international prostate symptom score (IPSS) and quality of life (QoL) at three months after treatment. Secondary endpoints were rates of complications, peak flow, residual urine and operation times. RESULTS: Preoperative characteristics showed no significant differences. Overall IPSS and QoL improved from 21 to 8 and 4 to 1.5, respectively, after three months of follow-up. No statistically significant differences between ThuFLEP and HoLEP were observed regarding median postoperative IPSS (8.5 vs. 7, p > 0.9), QoL (1 vs. 2, p = 0.6), residual urine (48 vs. 30ml, p = 0.065) and peak flow (19 vs. 17ml/s, p > 0.9). Similarly, safety profile was comparable with no statistically significant differences regarding rate of major complications (5.3 vs. 5.4%, p = 0.5), laser hemostasis time (3 vs. 2min, p = 0.2), use of additive electric coagulation (74 vs. 87%, p = 0.06) or electric coagulation time (8 vs. 8min, p = 0.4). CONCLUSIONS: In this prospective, randomized trial ThuFLEP showed non-inferior results compared to HoLEP in terms of functional outcomes measured by IPSS and QoL as primary endpoint. TRIAL REGISTRATION NUMBER: DRKS00032699 (18.09.2023, retrospectively registered).

Hysteroscopic Metroplasty Using Holmium: YAG Laser for Treatment of Septate Uterus.

STUDY OBJECTIVE: To demonstrate the safety, efficacy, and ease of hysteroscopic metroplasty using holmium:YAG (Ho:YAG) laser for treatment of septate uterus. DESIGN: Stepwise demonstration of surgical technique with narrated video footage. SETTING: Septate uterus is the most common type of uterine anomaly. The incidence of uterine septum in women presenting with infertility and recurrent abortions is 15.4% [1,2]. Hysteroscopic septal incision is associated with improvement in live-birth rate in these women [3]. Hysteroscopic metroplasty for septate uterus can be done with the use of scissors and energy sources such as monopolar and bipolar electrosurgery and lasers. Ho:YAG laser is commonly used by urologists for various surgeries because of its "Swiss Army Knife" action of cutting, coagulation, and vaporization [4]. Ho:YAG laser is known for its precision. It causes lesser depth of tissue injury and necrosis and minimal collateral thermal damage compared with the electrosurgical devices and other lasers used for hysteroscopic surgery [5-8]. This is advantageous in hysteroscopic metroplasty given that it reduces the risk of uterine perforation during surgery and hence uterine rupture in the subsequent pregnancy. Reduced collateral damage to the surrounding endometrium helps promote early endometrial healing and prevent postoperative intrauterine adhesions. A 28-year-old patient with history of 2 spontaneous abortions came to our hospital for investigations. 3D transvaginal sonography of the patient showed presence of partial septate uterus with a fundal indentation of 1.5 cm (Supplemental video 1). INTERVENTION: Diagnostic hysteroscopy followed by septal incision using Ho: YAG laser was planned. We used a 2.9 mm BETTOCCHI Hysteroscope (Karl Storz SE & Co.) with a 5 mm operative sheath. Normal saline was used as the distending medium and the intrauterine pressure was maintained at 80 to 100 mm Hg. The procedure was done under total intravenous anesthesia using propofol injection. Vaginoscopic entry into the uterus (without any cervical dilatation) showed evidence of a partial uterine septum with tubal ostia on either side of the septum. A 400 micron quartz fiber was passed through a laser guide into the 5-Fr working channel of the operative hysteroscope. Ho:YAG laser (Auriga XL 50-Watt, Boston Scientific) with power settings of 15 watts (1500 mJ energy at 10 Hz) was used. Incision of the septum was started at the apex of the septum in the midline and continued in a horizontal manner from side to side toward the base (Supplemental video 2). Incision of the septum is continued till the tip of the hysteroscope can move freely from one ostium to the other (Supplemental video 3). The operative time was 12 minutes. There were no intra- or postoperative complications. Postoperative estrogen therapy was given for 2 months in the form of estradiol valerate 2 mg (tablet, Progynova, Zydus Cadila) 12 hourly orally for 25 days and medroxyprogesterone acetate 10 mg (tablet, Meprate, Serum Institute of India, Ltd) 12 hourly orally added in the last 5 days [9]. 3D transvaginal ultrasound was done on day 8 of menses. It showed a triangular uterine cavity with a very small fundal indentation of 0.37 cm. A second look hysteroscopy that was done on day 9 of menses showed an uterine cavity of good shape and size [10]. Few fundal adhesions were seen and they were incised using Ho:YAG laser. The patient conceived 5 months after the primary surgery and delivered by cesarean section at 38 weeks, giving birth to a healthy baby of 2860 grams. There were no complications during her pregnancy and delivery. A comparative study is essential to prove its advantages over other energy sources for this surgery. CONCLUSION: Hysteroscopic metroplasty using Ho:YAG laser for treatment of septate uterus is a simple, precise, safe, and effective procedure. VIDEO ABSTRACT.

Experts' recommendations in laser use for the treatment of urolithiasis: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training-Research in Urological Surgery and Technology (T.R.U.S.T.)-Group.

PURPOSE: To identify laser lithotripsy settings used by experts for specific clinical scenarios and to identify preventive measures to reduce complications. METHODS: After literature research to identify relevant questions, a survey was conducted and sent to laser experts. Participants were asked for preferred laser settings during specific clinical lithotripsy scenarios. Different settings were compared for the reported laser types, and common settings and preventive measures were identified. RESULTS: Twenty-six laser experts fully returned the survey. Holmium-yttrium-aluminum-garnet (Ho:YAG) was the primary laser used (88%), followed by thulium fiber laser (TFL) (42%) and pulsed thulium-yttrium-aluminum-garnet (Tm:YAG) (23%). For most scenarios, we could not identify relevant differences among laser settings. However, the laser power was significantly different for middle-ureteral (p = 0.027), pelvic (p = 0.047), and lower pole stone (p = 0.018) lithotripsy. Fragmentation or a combined fragmentation with dusting was more common for Ho:YAG and pulsed Tm:YAG lasers, whereas dusting or a combination of dusting and fragmentation was more common for TFL lasers. Experts prefer long pulse modes for Ho:YAG lasers to short pulse modes for TFL lasers. Thermal injury due to temperature development during lithotripsy is seriously considered by experts, with preventive measures applied routinely. CONCLUSIONS: Laser settings do not vary significantly between commonly used lasers for lithotripsy. Lithotripsy techniques and settings mainly depend on the generated laser pulse's and generator settings' physical characteristics. Preventive measures such as maximum power limits, intermittent laser activation, and ureteral access sheaths are commonly used by experts to decrease thermal injury-caused complications.

Observation and comparison of gas formation during holmium:YAG laser lithotripsy of cystine, uric acid, and calcium oxalate stones: a chromatographic and electron microscopic analysis.

The primary aim of the present in vitro study is to analyze the chemical content of the bubbles occurring during the fragmentation of cystine stones with both the high-power and low-power holmium:YAG (Ho:YAG) lasers. The secondary aim is to discuss their clinical importance. Three types of human renal calculi calcium oxalate monohydrate (COM), cystine, and uric acid were fragmented with both low-power and high-power Ho:YAG lasers in separate experimental setups at room temperature, during which time it was observed whether gas was produced. After laser lithotripsy, a cloudy white gas was obtained, after the fragmentation of cystine stones only. A qualitative gas content analysis was performed with a gas chromatography-mass spectrometry (GC-MS) device. The fragments in the aqueous cystine calculi setup were dried and taken to the laboratory to be examined by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction analysis. No gas production was observed after fragmentation in the COM and uric acid stones. Free cystine, sulfur, thiophene, and hydrogen sulfide gas were produced by both low-power and high-power Ho:YAG laser lithotripsy of the cystine stones. In the SEM-EDX mapping analysis, a free cystine molecule containing 42.8% sulfur (S), 21% oxygen (O), 14.9% carbon (C), and 21% nitrogen (N) atoms was detected in the cystine stone experimental setup. The evidence obtained, which shows that hydrogen sulfide emerges in the gaseous environment during Ho:YAG laser fragmentation of cystine stones, indicates that caution is required to prevent the risk of in vivo production and toxicity.