The application of intravenous general anesthesia under nasopharyngeal airway assisted ventilation undergoing ureteroscopic holmium laser lithotripsy: A prospective, single-center, controlled trial.

To observe the effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation on patients undergoing ureteroscopic holmium laser lithotripsy. One hundred and twenty patients who underwent ureteroscopic holmium laser lithotripsy in our hospital were selected and randomly divided into nasopharyngeal airway group (research group) and laryngeal mask group (control group). These patients, respectively, received intravenous anesthesia under nasopharyngeal airway and laryngeal mask-assisted ventilation. The following evaluation indexes were compared and analyzed between the two groups, including anesthetic effect, hemodynamics, stress response, postoperative recovery, adverse reactions, etc. There were no significant differences in Visual Analog Scale, hemodynamics, and stress response between the two groups at each time point (P > 0.05). There were no significant differences in residence time and postoperative recovery time between the two groups (P > 0.05). The difference in airway establishment time between the two groups was statistically significant (P < 0.05), and cases with blood in the research group was significantly lower than those in the control group (P < 0.05). Patient satisfaction in research group was significantly higher than those in the control group (P < 0.05). The clinical effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation in ureteroscopic holmium laser lithotripsy is significant, which helps to stabilize patients' hemodynamics, reduce their stress response and adverse reactions, and improve the satisfaction rate of patient.

Construction of a Risk Prediction Model for Ureteral Stricture after Ureteroscopic Holmium Laser Lithotripsy.

Introduction: To analyze the influencing factors of ureteral stenosis after ureteroscopic holmium laser lithotripsy. Methods: The clinical data of 427 patients treated with ureteroscopic holmium laser lithotripsy were selected, and the patients were divided into two groups based on the presence or absence of ureteral stenosis after the operation. Univariate and multivariate logistic regression were used to analyze the independent risk factors for postoperative ureteral stenosis, and R software and regression coefficients were used to construct a predictive model. Results: After a 1-year follow-up of 427 patients, 28 patients (6.56%) developed ureteral stenosis; univariate analysis showed that the occurrence of ureteral stenosis after subureteral holmium laser lithotripsy was related to stone diameter, stone incarceration, degree of hydronephrosis, holmium laser injury of mucosa, and operation time (p < 0.05); further logistic regression analysis showed that a large stone diameter, stone incarceration, and moderate to severe hydronephrosis were independent risk factors for ureteral stenosis after ureteroscopic holmium laser lithotripsy (p < 0.05); According to H-L deviation degree and area under receiver operating characteristic curve test, the results show that the model has high accuracy (χ2 = 2.475, p = 0.613) and differentiation (0.875 [95% confidence interval or CI: 0.817-0.919]), and the external verification of the nomogram prediction model was carried out by the verification group. The results showed that the prediction probability of the calibration curve was close to the actual probability and had a good consistency (area under the curve: 0.873 [95 CI: 0.822-0.914]). Conclusion: The established nomogram model exhibits high accuracy and discriminative ability. It can effectively identify high-risk groups, enabling timely prevention of ureteral stenosis and minimizing the risk of postoperative ureteral stenosis.

Retrospective study of ureteral stenosis after holmium laser lithotripsy.

OBJECTIVE: To identify the factors influencing postoperative ureteral stenosis following holmium laser lithotripsy. METHODS: A retrospective study was conducted of 106 patients who underwent ureteroscopic holmium laser lithotripsy. The effects of variables including stone location, stone size, the duration of surgery, water intake, disease duration, and stone-associated polyps were investigated. RESULTS: Logistic regression analysis revealed significant associations of ureteral stenosis with stone location, stone size, duration of surgery, water intake, disease duration, and stone-associated polyps. Patients with proximal stones, with large stones, who underwent long surgical procedures, who drank a large amount of water, who had long-term disease, and who had stone-related polyps were more likely to develop postoperative ureteral stenosis. CONCLUSION: Significant perioperative complications of holmium laser lithotripsy are associated with prolonged disease, large ureteral stones, long incarceration periods, and the presence of polyps. Surgeons should consider these risk factors during the preoperative evaluation of patients and surgical planning to minimize the risk of postoperative ureteral stenosis.

Renal artery pseudoaneurysm presenting in a single functioning kidney with prior partial nephrectomy following flexible ureterorenoscopy: a case report.

Renal artery pseudoaneurysm (RAP) formation following flexible ureterorenoscopy (FURS) with laser lithotripsy is rare. Previous kidney surgery places patients at an increased risk due to potential vascular injury associated with renal intervention. In our case, a 62-year-old man with a single functioning right kidney and a history of right partial nephrectomy presented 10 days following FURS with holmium laser lithotripsy, complaining of gross hematuria. Attempted conservative management failed. Renal arteriography was done, which revealed a RAP that was managed with selective angioembolization. RAP following FURS can be serious if not managed properly. Most cases present with late gross hematuria. RAP can usually be demonstrated on renal arteriography. Selective angioembolization is the definitive treatment.

Urethral Calculus as an Uncommon Cause of Acute Urinary Retention in Women Diagnosis and Management: A Case Report.

Background: Urethral calculi causing acute urinary retention is a highly uncommon condition in women, which poses distinctive difficulties in diagnosis and treatment. This report presents the case of a 52-year-old woman who experienced acute urinary retention caused by a urethral stone. It emphasizes the effective use of minimally invasive methods and underscores the importance of comprehensive multidisciplinary treatment. Case presentation: A 52-year-old woman patient arrived with acute urinary retention symptoms that lasted 6 hours. She complained of pain in the perineal and periurethral regions. She struggled with poorly managed type 2 diabetes, metabolic syndrome, and frequent cystitis. The examination showed the presence of a 2-cm stone in the urethra. The treatment utilised retrograde propulsion and laser fragmentation. Postoperative magnetic resonance imaging results were normal, and follow-up care involved managing diabetes and adopting lifestyle changes to prevent the recurrence of cystitis and stones for 6 months. Conclusion: Urethral calculi exceptionally cause acute urinary retention in women. To achieve successful outcomes and prevent recurrence, it is crucial to prioritize prompt, minimally invasive treatment, and comprehensive management.

Relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy.

BACKGROUND: Soft ureteroscopic holmium laser lithotripsy is becoming increasingly popular as the preferred method for treating mid-to-lower ureteral stones. Studies have indicated that the size, composition, hardness, and fragility of the stones can impact the treatment's effectiveness. OBJECTIVE: To explore the relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy. METHODS: Our study on 126 patients undergoing ureteroscopic holmium laser lithotripsy for ureteral calculi from May 2020 to January 2022 categorized them into groups based on stone volume and CT value. We compared surgical outcomes and analyzed correlations between stone characteristics, operation parameters, and stone clearance rate to identify independent risk factors influencing treatment efficacy. RESULTS: Group A demonstrated significantly shorter operation durations and lower blood loss compared to Group B, along with higher single stone clearance rates and fewer postoperative complications. Similarly, Group C exhibited shorter operation times, reduced blood loss, higher stone clearance rates, and lower complication rates than Group D. Preoperative stone volume and CT value correlated positively with operation time and stone clearance rate, with both factors identified as independent risk factors affecting ureteral stone clearance following holmium laser lithotripsy. CONCLUSION: The stone volume and average CT value before ureteral soft lens laser lithotripsy show a positive correlation with operation time and efficiency, indicating that larger stone volumes and higher CT values lead to slower lithotripsy speeds and reduced operation efficiency. Furthermore, preoperative stone volume and average CT value are identified as independent risk factors for residual stones.

Analysis of Efficacy and Safety of Laparoscopy Plus Choledochoscopy Combined With Holmium Laser Lithotripsy for Choledocholithiasis and Hepatolithiasis.

Background: With the advancement of laparoscopic technology, the combination of laparoscopy, choledochoscopy, and holmium laser lithotripsy has emerged as an effective treatment modality for both choledocholithiasis and hepatolithiasis. This study aimed to assess the efficacy and safety of this approach. Methods: Retrospective analysis was conducted on the medical records of 76 patients diagnosed with choledocholithiasis and hepatolithiasis between April 2021 and March 2023. Patients were divided into two groups based on the treatment plan: the control group, which underwent traditional laparotomy and choledochoscopy lithotripsy (n = 38), and the experimental group, which underwent laparoscopy combined with choledochoscopy and holmium laser lithotripsy (n = 38). Comparative analysis was performed on various operation-related parameters, stone-free rate, complication rates, and changes in biochemical, liver function, inflammatory, stress response indicators, and pain scores between the two groups. Results: The experimental group demonstrated significantly shorter stone removal time, reduced intraoperative bleeding, and shorter hospital stay compared to the control group (P < 0.05). Moreover, the experimental group exhibited lower incidence of postoperative complications and lower pain scores at 2 weeks to 3 months post-operation (P < 0.05). Biochemical indicators including total bile acid (TBA), total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and glutamyl transpeptidase (GGT) were significantly lower in the observation group compared to the control group (P < 0.05). Additionally, stress and inflammation indicators were also lower in the experimental group (P < 0.05). Conclusions: The combination of laparoscopy, choledochoscopy, and holmium laser lithotripsy presents favorable therapeutic outcomes in the management of choledocholithiasis and hepatolithiasis, indicating its potential for widespread clinical application.

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.

Comparative analysis of scoring systems for patients undergoing retrograde intrarenal surgery with isolated lower calyx stones.

PURPOSE: It is critical to provide patients with accurate information on potential surgical outcomes during the preoperative phase. Several scoring systems have been developed for this specific purpose. This study aimed to examine the predicted efficacy of scoring systems in patients with isolated lower calyx stones who underwent retrograde intrarenal surgery (RIRS). METHODS: We performed a retrospective analysis of 85 patients who underwent RIRS for lower calyx stones between 2016 and 2023. The study computed each participant's Resorlu-Unsal Stone score (RUSS), R.I.R.S. scoring system score, Modified Seoul National University Renal Stone Complexity (S-ReSC) score, S.T.O.N.E. score, Ito's nomogram, and T.O.HO score. Residual stones less than 4 mm were classified as clinically insignificant residual fragments (CIRFs) and regarded as successful. Following that, we used receiver-operating characteristic (ROC) curves to compare various scoring systems' success predictions. RESULTS: The median scores for RUSS, R.I.R.S. scoring system, Modified S-ReSC, S.T.O.N.E., Ito's nomogram, and T.O.HO score were 1 (1), 7 (2), 2 (0), 11 (1), 18 (4), and 7 (1), respectively. When CIRF cases were included, the stone-free rate increased to 80%. Only Ito's nomogram from scoring systems has a statistically significant cut-off value for success in ROC analysis (p = 0.021). In multivariate analysis, stone volume and preoperative hydronephrosis were associated with success (p = 0.004 and p = 0.035, respectively). CONCLUSION: In the multivariate analysis, none of the scoring systems were significantly associated with success. Hence, a new scoring system must be developed exclusively for patients with isolated lower pole stones undergoing RIRS.

Pharmacological Modulation of Intrarenal Pressure in a Porcine Model Using a Novel Isoprenaline-Eluting Guidewire.

Introduction: Several complications of retrograde intrarenal surgery have been attributed to inadvertent increases in intrarenal pressure. We recently described the development of an innovative isoprenaline-eluting guidewire (IsoWire). The objective of this study was to investigate the impact of this IsoWire on the intrarenal pressure and evaluate its safety. Materials and Methods: This study was performed in 17 renal units using a porcine model. As controls, the intrarenal pressure, heart rate, and mean arterial pressure were measured for a duration of six minutes with a standard guidewire placed in the renal pelvis. For the experiment, the conventional guidewire was substituted with the IsoWire and the same parameters were measured. Blood samples were taken at one-minute intervals to measure plasma isoprenaline levels. This procedure was repeated on the opposite side. Results: The mean intrarenal pressure reduction was 29% (95% CI: 13%-53%). The mean isoprenaline effect time was 174 seconds. No changes in heart rate (p = .908) or mean arterial pressure (p = .749) were recorded after IsoWire insertion. Plasma isoprenaline levels were below the quantitation threshold. Isoprenaline concentrations in the plasma were below the quantification threshold. Ureteroscopy revealed no ureteral lesions. Conclusions: The IsoWire demonstrated a safe and effective reduction of intrarenal pressure. Additional research is necessary to determine whether ureteral smooth muscle relaxation generated by isoprenaline facilitates easier insertion of a ureteral access sheath, decreases the incidence of ureteral access sheath related ureteral lesions, or even encourage the practice of sheathless retrograde intrarenal surgery.

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.

Safety and Efficacy of Ureteroscopic Laser Lithotripsy in the Management of Ureteric Calculi in Pregnancy-Experience of a Tertiary Care Center.

Introduction: Ureteric colic in pregnancy is one of the common non-obstetric reasons for emergency department visits. Ureteric calculi present a significant threat to maternal and fetal health and definitive management often becomes necessary. Our aim is to assess the safety and efficacy of ureteroscopic laser lithotripsy in the management of ureteric stones in pregnancy. Material and methods: This is a prospective observational study of 3 years carried at a tertiary referral center. It includes all pregnant patients who underwent ureteroscopic laser lithotripsy for ureteric stones. Results: A total of 29 pregnant patients underwent ureteroscopic laser lithotripsy at our center in 3 years. The mean age of patients was 33.5 ± 6.2 years, and the mean gestation age at the time of ureteroscopy was 23.34 ± 5.9 weeks. The average stone size was 8.3 ± 3.6 mm and was predominantly found in upper ureter (62%). The mean operative time was 31 ± 8.9 min, and the average laser energy spent was 4.3 ± 1.1 kJ/case. There was no major Intraoperative complication, and the average hospital stay was 2.5 ± 1.5 days. Complete stone clearance was achieved in 93.1% of cases. Conclusion: Ureteroscopic laser lithotripsy is safe and effective treatment of ureteric stones in terms of obstetric outcome and stone clearance in pregnancy.

Assessment of stone ablation rate using the Moses technology modes with different energy and pulse settings: An experimental study.

Objectives: To compare lithotripsy ablation rate with the Moses modes versus conventional pulse modes when using the Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) laser. Methods: The Lumenis® Pulse P120H Holmium Laser System and a 365 µm Moses D/F/L fiber were used to assess stone ablation rate in conventional Short and Long Pulse as well as Moses Contact and Distance at 10 W (0.5Jx20Hz and 2Jx5Hz) and 60 W (1Jx60Hz and 2Jx30Hz). Hard and soft phantom stones were formed, and all tests were conducted in a custom experimental configuration installed in a saline-filled bath. The laser was delivered up to 3 kJ of total energy. The fragmentation pattern was assessed via photographs in each cohort. Results: The time to reach the target energy was 5 min and 50 s in all 10 W and 60 W trials, respectively. In both stone types, ablation was more effective when high-power, high-energy and Moses Distance was utilized. In soft stones, the lowest ablation rate was detected in the Long Pulse modality in all power, energy and frequency settings. Overall, when dusting settings (high-frequency, low-energy) were used, a deeper single cavitation was observed rather than small cavitations. Conclusions: The most effective pulse modality as evaluated via stone ablation rate depends on the stone hardness as well as energy and frequency settings. In both hard and soft stones, ablation is more effective when 60 W (2Jx30Hz) power settings and Moses Distance are used. Tailored laser settings in terms of energy and frequency could be set for each case scenario.

Do not stumble over the same "stone" twice: a case series of endogenous endophthalmitis secondary to severe systemic diseases.

BACKGROUND: Endogenous endophthalmitis (EE) is a rare but highly destructive eye emergency secondary to systemic infection. Acute endophthalmitis can lead to irreversible vision impairment or even loss of the whole eye, unless being diagnosed and treated promptly. CASE PRESENTATION: This study reports three typical EE cases of endogenous endophthalmitis secondary to different severe systemic diseases. Patients were recruited from the Department of ophthalmology at Zhongnan hospital of Wuhan University and the Department of ophthalmology at the Second Affiliated Hospital of Fujian Medical University. Patients were followed up for up to 60 days. Among these cases, the eye symptoms is the initial manifestations while secondary to original different special systemic conditions. Patients have been treated under dynamically prompt response undergoing systemic treatment and eye treatment at the same time. Best corrected visual acuity were 20/40, 20/60 and light perception during follow-up evaluation. CONCLUSIONS: Our observation suggest that prompt identification and treatment could save patients' vision from EE.

Utility of the modified 5-item frailty index as a predictor of postoperative febrile urinary tract infection in patients who underwent ureteroscopy with laser lithotripsy.

PURPOSE: This study aimed to assess the effect of the modified 5-item frailty index on perioperative complications and surgical outcomes in patients who underwent ureteroscopy with laser lithotripsy for upper urinary tract stones. METHODS: Patients who underwent ureteroscopy with laser lithotripsy for upper urinary tract stones between 2019 and 2022 were reviewed retrospectively. Assessment was performed using the modified 5-item frailty index based on medical history (hypertension, diabetes, heart failure, chronic obstructive pulmonary disease) and functional status. Patients were categorized into the high (≥ 2) and low (≤ 1) modified 5-item frailty index groups based on the frailty score. We compared the perioperative complications and surgical outcomes between the two groups. RESULTS: Seventy-one (15.8%) and 393 (84.1%) of the 467 patients were classified into the high and low modified 5-item frailty index groups, respectively. The high modified 5-item frailty index group exhibited a significant association with increased febrile urinary tract infections compared to the low modified 5-item frailty index group [≥ 37.8 °C: 15 (20.3%) vs 13 (3.3%), p < 0.001; ≥ 38 °C: 9 (12.2%) vs 7 (1.8%), p < 0.001]. Surgical outcomes, including operative time and stone-free rate, did not differ significantly between the two groups. CONCLUSION: The modified 5-item frailty index is valuable for predicting postoperative complications, particularly febrile urinary tract infections, after ureteroscopy with laser lithotripsy for upper urinary tract stones. This index allows for practical preoperative risk assessment in patients who underwent ureteroscopy with laser lithotripsy.

Japanese survey of perioperative complications and ureteral stricture after ureteroscopy with laser lithotripsy for upper urinary tract stones in multicenter collaborative study.

OBJECTIVES: This study aimed to investigate perioperative complications and the details of postoperative ureteral stricture after ureteroscopy with laser lithotripsy (URS-L) for upper urinary tract stones in Japan. METHODS: Patient data on intra- and postoperative complications after ureteroscopy using URS-L were retrospectively collected from multiple centers in Japan between April 2017 and March 2020 with the cooperation of the Japanese Society of Endourology and Robotics. Data included the number of patients undergoing URS-L, number and type of intra- and postoperative complications, and detailed characteristics of postoperative ureteral stricture. RESULTS: In total, 14 125 patients underwent URS-L over 3 years at 82 institutions. Annual URS-L numbers gradually increased from 4419 in 2017, to 4760 in 2018, and 4946 in 2019. The total complication rate was 10.5%, which was divided into intra-operative complications in 1.40% and postoperative complications in 9.18%. The annual incidences of intra- and postoperative complications were not significantly different from year to year (p = 0.314 and p = 0.112). Ureteral perforation, ureteral avulsion, and the intra-operative conversion rate were 1.35%, 0.03%, and 0.02%, respectively. Fever >38°C, septic shock, blood transfusion, and postoperative mortality were 7.44%, 0.81%, 0.07%, and 0.04%, respectively. Ureteral stricture occurred in 0.8% of cases. The median length of stricture site was 10.0 mm and the success rate of stricture treatment was 54.6%. CONCLUSION: Although URS-L utilization has increased in Japan, the annual complication rate has remained steady. Although URS-L is a useful and less invasive procedure, devastating complications can still occur.

Flexible ureteroscopic treatment of kidney stones: How do the new laser systems change our concepts?

Objective: Flexible ureteroscopy (fURS) has become a widely accepted and effective technique for treating kidney stones. With the development of new laser systems, the fURS approach has evolved significantly. This literature review aims to examine the current state of knowledge on fURS treatment of kidney stones, with a particular focus on the impact of the latest laser technologies on clinical outcomes and patient safety. Methods: We conducted a search of the PubMed/PMC, Web of Science Core Collection, Scopus, Embase (Ovid), and Cochrane Databases for all randomized controlled trial articles on laser lithotripsy in September 2023 without time restriction. Results: We found a total of 22 relevant pieces of literature. Holmium laser has been used for intracavitary laser lithotripsy for nearly 30 years and has become the golden standard for the treatment of urinary stones. However, the existing holmium laser cannot completely powder the stone, and the retropulsion of the stone after the laser emission and the thermal damage to the tissue have caused many problems for clinicians. The introduction of thulium fiber laser and Moses technology brings highly efficient dusting lithotripsy effect through laser innovation, limiting pulse energy and broadening pulse frequency. Conclusion: While the holmium:yttrium-aluminum-garnet laser remains the primary choice for endoscopic laser lithotripsy, recent technological advancements hint at a potential new gold standard. Parameter range, retropulsion effect, laser fiber adaptability, and overall system performance demand comprehensive attention. The ablation efficacy of high-pulse-frequency devices relies on precise targeting, which may pose practical challenges.

Proof-of-concept for a novel nanotechnology-based treatment for urolithiasis.

Proof-of-concept of photonic lithotripsy in an in vitro setting and its ability to fragment the most common stone types is demonstrated. Effectiveness of different classes of photonic nanoparticles in fragmenting human stones is assessed. De-identified human stones were collected after institutional approval. Stones of a size range between 2-4 mm were rehydrated in simulated urine for 24 h. Stones were then coated with a solution of nanoparticles prior to activation with either a 785 nm or 1320 nm near-infrared energy source. Photonic lithotripsy achieved greater than 70% success rate in fragmentating calcium oxalate monohydrate stones using carbon-based nanoparticles for both near-infrared wavelengths. For gold-based nanoparticles, there was a similar success rate with the 785 nm wavelength but a significant decrease when using the 1320 nm wavelength energy source. All stones fragmented with the energy source at a distance ≥ 20 mm from the stone's surface. Limitations include the use of mixed-composition stones, a lack of complete stone immersion in liquid during treatment, and smaller stone size. Different classes of nanoparticles when excited with a near-infrared energy source can fragment common stone types in vitro. This technology has the potential to change the way we approach and treat patients with urolithiasis in a clinical setting.

Introducing an lsoprenaline Eluting Guidewire: Report on its Design and the Results of the Dose-Determining Pilot Study.

Introduction: Retrograde intrarenal surgery (RIRS) is associated with complications, many of which are related to the intrarenal pressure (IRP). We aim to describe the design of a novel isoprenaline-eluting guidewire ("IsoWire") and present the results from the first in vitro release studies and the first animal studies showing its effect on IRP. Materials and Methods: The IsoWire comprises a Nitinol core surrounded by a stainless-steel wire wound into a tight coil. The grooves created by this coil provided a reservoir for adding a hydrogel coating into which isoprenaline, a beta-agonist, was loaded. Animal studies were performed using a porcine model. For the control, IRP, heart rate (HR), and mean arterial pressure (MAP) were measured continuously for 6 minutes with a standard guidewire in place. For the experiment, the standard hydrophilic guidewire was removed, the IsoWire was inserted into the renal pelvis, and the same parameters were measured. Results: In vitro analysis of the isoprenaline release profile showed that most (63.9 ± 5.9%) of the loaded drug mass was released in the 1st minute, and almost all of the drug was released in the first 4 minutes exponentially. Porcine studies showed a 25.1% reduction in IRP in the IsoWire that released 10 µg in the 1st minute; however, there was a marked increase in HR. The average percentage reduction in IRP was 8.95% and 21.3% in the IsoWire that released 5 and 7.5 µg of isoprenaline, respectively, with no changes in HR or MAP. Conclusions: The IsoWire, which releases 5 and 7.5 µg of isoprenaline in the 1st minute, appears to be safe and effective in reducing the IRP. Further studies are needed to establish whether the isoprenaline-induced ureteral relaxation will render easier insertion of a ureteral access sheath, reduce IRP during sheathless RIRS, or even promote the practice of sheathless RIRS.

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.