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.

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.

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.

Plasma formation in holmium:YAG laser lithotripsy.

OBJECTIVES: During holmium:yttrium-aluminum-garnet (holmium:YAG) laser lithotripsy to break urinary stones, urologists frequently see flashes of light. As infrared laser pulses are invisible, what is the source of light? Here we studied the origin, characteristics, and some effects of flashes of light in laser lithotripsy. METHODS: Ultrahigh-speed video-microscopy was used to record single laser pulses at 0.2-1.0 J energy lasered with 242 µm glass-core-diameter fibers in contact with whole surgically retrieved urinary stones and hydroxyapatite (HA)-coated glass slides in air and water. Acoustic transients were measured with a hydrophone. Visible-light and infrared photodetectors resolved temporal profiles of visible-light emission and infrared-laser pulses. RESULTS: Temporal profiles of laser pulses showed intensity spikes of various duration and amplitude. The pulses were seen to produce dim light and bright sparks with submicrosecond risetime. The spark produced by the intensity spike at the beginning of laser pulse generated a shock wave in the surrounding liquid. The subsequent sparks were in a vapor bubble and generated no shock waves. Sparks enhanced absorption of laser radiation, indicative of plasma formation and optical breakdown. The occurrence and number of sparks varied even with the same urinary stone. Sparks were consistently observed at laser energy >0.5 J with HA-coated glass slides. The slides broke or cracked by cavitation with sparks in 63 ± 15% of pulses (1.0 J, N = 60). No glass-slide breakage occurred without sparks (1.0 J, N = 500). CONCLUSION: Unappreciated in previous studies, plasma formation with free-running long-pulse holmium:YAG lasers can be an additional physical mechanism of action in laser procedures.

Ablation rates with Holmium:YAG and Thulium Fiber Laser: Influence of the stone phantom homogeneity. An in vitro study.

OBJECTIVES: The lithotripsy efficiency (LE) in vitro study requires artificial or human stone samples (AS, HS). With the development of dusting lithotripsy, less ex vivo HS are available. We aimed to compare Thulium Fiber Laser (TFL) and Holmium:YAG (Ho:YAG)'s LE and define the most accurate LE parameter. METHODS: Hard and soft homogenous- and heterogenous-AS (Ho-AS, He-AS) were made to reproduce calcium-oxalate monohydrate and uric acid stones, respectively by a rapid or slow brewing of BegostonePlus (Bego) and distilled water. One hundred and fifty and 272µm-laser fibers, connected to 50W-TFL and 30W-HoYAG generators, compared three settings for TFL (FD: 0.15J/100Hz; D: 0.5J/30Hz; Fr: 1J/15Hz) and two for Ho:YAG (D-Fr). An experimental setup consisted in immerged 10mm cubic stone phantoms with a 20 seconds' lasing spiral, in contact mode, repeated four times. Stones were dried, weighted and µ-scanned (ablation weight and volume [AW and AV]). RESULTS: With He-AS, dusting AV were four- and three-fold higher with TFL compared to Ho:YAG against hard and soft (P<0.05). In fragmentation, AV were two-fold higher with TFL compared to Ho:YAG against hard (P<0.05) and soft (P<0.05). Experiments with Ho-AS were associated with non-significant differences when comparing TFL-150µm and TFL-272µm. The ablation weight-volume correlation coefficients was higher with Ho-AS than with He-AS (P<0.0001), and with hard than soft AS. If the LE can be estimated by the AW with hard AS, this approximation is not consistent for soft AS. CONCLUSION: TFL presented higher ablation rates than Ho:YAG, significant with He-AS. If the AW is acceptable and less expensive for hard Ho-AS, AV are more accurate for He-AS, which are suggested to imitate closely HS.

Comparison of vacuum suction ureteroscopic laser lithotripsy and traditional ureteroscopic laser lithotripsy for impacted upper ureteral stones.

PURPOSE: To compare a novel vacuum suction ureteroscopic laser lithotripsy (VS-URS) with traditional ureteroscopic laser lithotripsy (T-URS) for impacted upper ureteral stones and to better define the potential benefits of VS-URS. METHODS: Between May 2019 and March 2021, 158 patients with impacted upper ureteral stones underwent ureteroscopic holmium-YAG laser lithotripsy. Of these, 76 underwent VS-URS and 82 underwent T-URS. In VS-URS procedures, the vacuum suction device is composed of a 5F ureteral catheter and a tee joint. The ureteral catheter is linked to the vacuum aspirator by the sidearm of the tee joint, and a 200 µm fiber is inserted through the tee joint and the ureteral catheter into the stone site for lithotripsy. RESULTS: When compared to the T-URS group, the VS-URS group had a shorter mean operation time (38.18 ± 6.37 min vs. 46.65 ± 5.66 min; P = 0.000), lower fever rate (3.9% vs. 14.6%; P < 0.022), less stone retropulsion (5.3% vs. 18.3%; P = 0.012), lower extra management rate (6.58% vs. 21.95%; P = 0.006), and a higher stone-free rate of the first postoperative day (88.2% vs. 72.0%; P = 0.011). There were no significant differences in stone-free rates 1 month after surgery between groups (94.7% vs. 92.7%; P = 0.748). CONCLUSIONS: VS-URS is an effective modality for impacted upper ureteral stones, and has a shorter operating time, lower fever rate, less stone retropulsion, and a higher primary stone-free rate compared with T-URS.

Learning curve and functional outcomes after laser enucleation of the prostate for benign prostate hyperplasia according to surgeon's caseload.

PURPOSE: To evaluate the impact of surgical caseload on safety, efficacy, and functional outcomes of laser enucleation of the prostate (LEP) applying a structured mentoring program. METHODS: Patient characteristics, perioperative data, and functional outcomes were analyzed descriptively. Linear and logistic regression models analyzed the effect of caseload on complications, functional outcomes and operative speed. Within the structured mentoring program a senior surgeon was present for the first 24 procedures completely, for partial steps in procedures 25-49, and as needed thereafter. RESULTS: A total of 677 patients from our prospective institutional database (2017-2022) were included for analysis. Of these, 84 (12%), 75 (11%), 82 (12%), 106 (16%), and 330 patients (49%) were operated by surgeons at (A) < 25, (B) 25-49, (C) 50-99, (D) 100-199, and (E) ≥ 200 procedures. Preoperative characteristics were balanced (all p > 0.05) except for prostate volume, which increased with caseload. There was no significant difference in change of IPSS, Quality of life, ICIQ, pad usage, peak urine flow, residual urine, and major complications (Group A: 8.3 to E: 7.6%, p = 0.2) depending on the caseload. Caseload was not associated (Odds ratio: 0.7-1.4, p > 0.2) with major complications in the multivariable logistic regression model. Only operating time was significantly shorter with increasing caseload in the multivariable analysis (111-55 min, beta 23.9-62.9, p < 0.001). CONCLUSION: With a structured mentoring program, the safety and efficacy of LEP can be ensured even during the learning curve with very good outcome quality. Only the operating time decreases significantly with increasing experience of the surgeon.

The effect of prolonged laser activation on irrigation fluid temperature: an in vitro experimental study.

PURPOSE: To investigate the effect of prolonged laser activation on irrigation fluid temperature by varying the power settings flow rate (10-30 ml/min). MATERIALS AND METHODS: An experimental study using a 20 ml syringe, 12/14 ureteral access sheath, a dual-lumen catheter and a thermocouple was performed. The laser was fired with 12 W (0.3 J × 40 Hz), 40 W (1 J × 40 Hz), 60 W (1.5 J × 40 Hz) using Quanta Ho 150 W (Quanta System, Samarate, Italy). All trials were performed with fluid outflow rate of 10, 20 and 30 ml/min with the fixed fluid volume at 10 ml. RESULTS: Continuous laser activation for 10 min with the outflow rate of 10 ml/min using only 12 W resulted to continuous temperature rise to as high as 83 °C. Similar rise of temperatures were observed for 40 W and 60 W with 10 ml/min outflow rate with intermittent laser activation. With 20 and 30 ml/min outflow rates the maximum temperatures for all power settings were below the threshold (< 43 °C). However, the time to reach the same total emitted energy was 60% and 40% shorter 60 W and 40 W, respectively. CONCLUSION: Our study found that continuous laser activation with as less as 12 W using 10 ml/min outflow rate increased the irrigation fluid temperature above the threshold only after 1 min. In the current experimental setup, with the fluid outflow rate of 20 and 30 ml/min safe laser activation with 60 W and 40 W (temperature < 43 °C) can be achieved reaching the same total emitted energy as with 12 W in significantly shorter time period.

The holmium:YAG laser lithotripsy-a non-invasive tool for removal of midsize stones of major salivary glands.

Incorporeal lithotripsy by using holmium:YAG laser has been recently successfully spread and used in the treatment of urolithiasis. Although this method is not as common in salivary gland surgery, it is also recommended for endoscopic treatment of sialolithiasis. In this study, we decided to analyse effectiveness of holmium:YAG laser method among patients with midsize stones as the treatment in this particular population is still not determined and remains in dispute. Thus, the primary aim of the study is a prospective, complex analysis of incorporeal holmium:YAG laser lithotripsy effectiveness and safety in patients suffering from sialolithiasis. The examined group consisted of 32 consecutive patients, 17 female (53%) and 15 male (47%). The average age was 42 (age range 22-70). In our series, sialoendoscopy with intraductal lithotripsy was performed in patients with wide range of stone's diameter (3 to 10 mm). The calculi were removed with foreign body forceps or retrieval basket, after stone fragmentation with holmium:YAG laser. The power of the laser during surgery was set at 2.5 to 3.5 W. One shot energy equalled 0.5-0.7 J with frequency of 5 Hz. The bivariate Pearson Correlation and a point-biserial correlation were used to analyse the data. Total success rate of holmium:YAG laser lithotripsy in this consecutive group was equal to 90% and efficacy in the group with excluded cases when endoscopic approach difficulties were experienced (stone not visible) reached 93%. The long-term follow-up revealed that in 26 patients (84%), complete recovery was achieved. Two patients developed Wharton's duct stenosis and one Stensen's duct orifice stenosis (9.5%), of whom one required reoperation. Two patients eventually underwent total excision of submandibular gland. Sialoendoscopy combined with incorporeal laser-assisted lithotripsy proved to be effective and safe method for treatment of sialothiasis with midsize stones (4-8 mm) in population of clinic. Even taking into account the prevalence of complications associated with holmium:YAG laser, it is still safer alternative compared to open surgery where there is a significant risk of the bleeding, wound infection or injury of the facial nerve.

Temperature rise during ureteral laser lithotripsy: comparison of super pulse thulium fiber laser (SPTF) vs high power 120 W holmium-YAG laser (Ho:YAG).

PURPOSE: The holmium-YAG (Ho:YAG) Laser system is the current gold standard for laser lithotripsy (LL). Super Pulse Thulium Fiber Laser (SPTF) has emerged as an effective alternative. We compared the temperature profile of both the 120 W Ho:YAG and the 60 W SPTF systems during ureteral lithotripsy. METHODS: Antegrade ureteroscopy with LL was performed in ex-vivo porcine kidneys with 3 mm Begostones. Intra-ureteral temperature was measured using one probe proximal and one distal to the site of lithotripsy. LL was performed using a 200 µm core fiber at dusting (SPTF-0.1 J, 200 Hz, SP; Ho:YAG-0.3 J, 70 Hz, LP) and fragmenting (0.8 J, 8 Hz, SP for both) settings for 5 s. Fifteen repetitions were recorded for each laser at each setting. Tissue samples of the ureter were collected for histological analysis. RESULTS: There was a rise in temperature at the site of lithotripsy using both systems at every setting evaluated. The median temperatures were greater for the SPTF on the fragmenting setting (33.3 °C vs 30.0 °C, p = 0.004). On the dusting setting, the median temperature was not statistically greater for Ho:YAG (40.6 °C vs 35.8 °C, p = 0.064), (Graphic 1). Histological analysis did not show any signs of injury or necrosis in any of the tested settings. CONCLUSION: Higher power settings used for dusting have a higher temperature rise in the ureter during lasering. Median ureteral intra-luminal temperature rise during LL was equivalent during dusting and higher in the SPTF during fragmentation, but neither reached the threshold for thermal injury based on the duration of exposure.

Tissue effects of a newly developed diode pumped pulsed Thulium:YAG laser compared to continuous wave Thulium:YAG and pulsed Holmium:YAG laser.

PURPOSE: The objective of this study is to evaluate the laser-tissue effects of laser radiation emitted by a newly developed high frequency pulsed Tm:YAG laser in comparison to the continuous wave Tm:YAG laser and the pulsed Ho:YAG laser. METHODS: Ex-vivo experiments were performed on freshly slaughtered porcine kidneys in a physiological saline solution. Experiments were performed using two different laser devices in different settings: A Tm:YAG laser was operated in a pulsed mode up to 300 Hz and in a continuous wave (CW) mode. Results were compared with a 100 W standard pulsed Ho:YAG laser system. Comparative tissue experiments were performed at 5 W, 40 W and 80 W. The incision depth and the laser damage zone were measured under a microscope using a calibrated ocular scale. RESULTS: Increased laser power resulted in increased incision depth and increased laser damage zone for all investigated lasers in this set-up. The Ho:YAG created the largest combined tissue effect at the 5 W power setting and seems to be the least controllable laser at low power for soft tissue incisions. The CW Tm:YAG did not incise at all at 5 W, but created the largest laser damage zone. For the new pulsed Tm:YAG laser the tissue effect grew evenly with increasing power. CONCLUSION: Among the investigated laser systems in this setting the pulsed Tm:YAG laser shows the most controllable behavior, insofar as both the incision depth and the laser damage zone increase evenly with increasing laser power.

Effects of irrigation fluid temperature during flexible ureteroscopic holmium laser lithotripsy on postoperative fever and shivering: a randomized controlled trial.

BACKGROUND: Flexible ureteroscopic holmium laser lithotripsy is used to treat urinary tract calculi, but postoperative complications include shivering, fever and infection. To investigate the effects of irrigation fluid temperature on postoperative complications. METHODS: This randomized controlled trial included 120 consecutive patients undergoing flexible ureteroscopic holmium laser lithotripsy at the Urology Department, Suining Central Hospital, Sichuan, China between January 2017 and July 2019. Patients were randomized 1:1:1 into three groups (17 °C, 27 °C or 37 °C). Primary outcome was fever incidence (body temperature > 37.5 °C) within 48 h after surgery. Secondary outcomes included shivering incidence during recovery from anesthesia, white blood cell count (WBC), serum procalcitonin (PCT) and incidence of suspected infection (temperature > 38.5 °C and PCT > 0.5 µg/L). RESULTS: There were 108 patients, (17 °C group, n = 36; 27 °C group, n = 35; 37 °C group, n = 37), received flexible ureteroscopic holmium laser lithotripsy and analyzed. Age, gender distribution, body mass index, ASA grade, stone burden, preoperative creatinine, preoperative core temperature and irrigation fluid volume did not differ significantly between groups. 17 °C, 27 °C and 37 °C groups exhibited significant differences in the incidences of postoperative fever (38.9% vs. 17.1% vs. 13.5%) and shivering (22.2% vs. 5.7% vs. 2.7%) (p < 0.05 for all pairwise comparisons). There was no significant difference of WBC, PCT and incidence of suspected infection in 37 °C or 27 °C group compared with 17 °C group. One case each of flash pulmonary edema and bleeding occurred in 37 °C group. CONCLUSION: Warming the irrigation fluid can reduce the incidence of postoperative fever and shivering, but further studies are needed to determine the optimal temperature. Trial registration The trial was registered at the Chinese Clinical Trials Registry and allocated as ChiCTR2000031683. The trial was registered on 07/04/2020 and this was a retrospective registration.

Does working channel position influence the effectiveness of flexible ureteroscopy? Results from an in vitro study.

OBJECTIVE: To evaluate whether the position of the working channel affects the effectiveness of flexible ureteroscopy. MATERIALS AND METHODS: We compared the ureteroscopes Flex-X2S and Flex-XC (working channel at the 9 and 3 o'clock positions, respectively) in eight cavities of a K-Box model, simulating the distribution of the right and left intrarenal calyces. In the first and second settings, each cavity contained a 1-cm stone, lying on the bottom and fixed on the anterior sheet covering the box, respectively. In the third setting, the posterior and lateral surface of each cavity was draped with graph paper. Once the flexible ureteroscope entered each cavity, we measured and compared (i) the proportion of stone surface targeted by the laser (STL) and (ii) the proportion of graph paper burned by the laser (PBL) obtained with the two instruments. RESULTS: Higher STLs and PBLs were obtained with the 3 o'clock position than the 9 o'clock position in the right posterior and left anterior cavities (mean ± sd STL 87% ± 15% vs 46% ± 38% and 78% ± 35% vs 43% ± 24%, respectively; P < 0.05), and on the right posterior surfaces of the middle-lower/lower cavities (PBL 72% vs 31% and 77% vs 35%, respectively; P < 0.01) and on the left lateral surface of the lower cavities (PBL 45% vs 25%; P = 0048), respectively. Conversely, the 9 o'clock position provided higher STLs and PBLs than the 3 o'clock position in the left posterior and right anterior cavities (mean ± sd STL 84% ± 20% vs 65% ± 28% and 79% ± 30% vs 44% ± 35%, respectively; P ≤ 0.02), and on the left posterior and right lateral surfaces of the lower cavities (PBL 59% vs 34% and 50% vs 21%, respectively; P ≤ 0.04). CONCLUSIONS: The position of the working channel of the flexible ureteroscope should be considered when planning flexible ureteroscopy, especially when dealing with the lower pole.

Preclinical comparison of superpulse thulium fiber laser and a holmium:YAG laser for lithotripsy.

PURPOSE: A superpulse (500 W peak power) thulium fiber laser operating at a 1940 nm wavelength, suitable for lithotripsy, has recently been developed. The goal of this study was to compare stone fragmentation and dusting performance of the prototype superpulse thulium fiber laser with leading commercially available, high-power holmium:YAG lithotripters (wavelength 2100 nm) in a controlled in vitro environment. METHODS: Two experimental setups were designed for investigating stone ablation rates and retropulsion effects, respectively. In addition, the ablation setup enabled water temperature measurements during stone fragmentation in the laser-stone interaction zone. Human uric acid (UA) and calcium oxalate monohydrate (COM) stones were used for ablation experiments, whereas standard BegoStone phantoms were utilized in retropulsion experiments. The laser settings were matched in terms of pulse energy, pulse repetition rate, and average power. RESULTS: At equivalent settings, thulium fiber laser ablation rates were higher than those for holmium:YAG laser in both dusting mode (threefold for COM stones and 2.5-fold for UA stones) and fragmentation mode (twofold for UA stones). For single-pulse retropulsion experiments, the threshold for onset of stone retropulsion was two to four times higher for thulium fiber laser. The holmium:YAG laser generated significantly stronger retropulsion effects at equal pulse energies. The water temperature elevation near the laser-illuminated volume did not differ between the two lasers. CONCLUSIONS: Distinctive features of the thulium fiber laser (optimal wavelength and long pulse duration) resulted in faster stone ablation and lower retropulsion in comparison to the holmium:YAG laser.

Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser.

PURPOSE: To compare the operating modes of the Holmium:YAG laser and Thulium fiber laser. Additionally, currently available literature on Thulium fiber laser lithotripsy is reviewed. MATERIALS AND METHODS: Medline, Scopus, Embase, and Web of Science databases were searched for articles relating to the operating modes of Holmium:YAG and Thulium fiber lasers, including systematic review of articles on Thulium fiber laser lithotripsy. RESULTS: The laser beam emerging from the Holmium:YAG laser involves fundamental architectural design constraints compared to the Thulium fiber laser. These differences translate into multiple potential advantages in favor of the Thulium fiber laser: four-fold higher absorption coefficient in water, smaller operating laser fibers (50-150 µm core diameter), lower energy per pulse (as low as 0.025 J), and higher maximal pulse repetition rate (up to 2000 Hz). Multiple comparative in vitro studies suggest a 1.5-4 times faster stone ablation rate in favor of the Thulium fiber laser. CONCLUSIONS: The Thulium fiber laser overcomes the main limitations reported with the Holmium:YAG laser relating to lithotripsy, based on preliminary in vitro studies. This innovative laser technology seems particularly advantageous for ureteroscopy and may become an important milestone for kidney stone treatment.

Negative-Pressure Ureteroscopic Holmium-YAG Laser Lithotripsy for Ureteral Stones.

OBJECTIVES: The aim of this study was to describe a novel negative-pressure laser lithotripsy device to overcome the deficiencies of the conventional procedure. PATIENTS AND METHODS: Between August 2018 and March 2019, 78 patients with a single ureteral stone underwent retrograde ureteroscopy with a Wolf 8F/9.8F rigid ureteroscope and a 200-µm holmium-YAG laser. The mean stone size was 11.8 mm, measured for the maximum length. The negative-pressure laser lithotripsy device consists of an F5 ureter catheter and a T joint. The closed tip of an F5 ureter catheter is cut off, and it is then inserted within one opening of the T joint. The 200-µm laser fiber is introduced into the ureteral catheter through the other opening of the T joint. The third opening of the T joint is connected to the negative-pressure pipe. The valve end of the Foley catheter is used for sealing the cap. Continuous suction and active irrigation throughout the lithotripsy could maintain adequate visibility. RESULTS: All ureteroscopic procedures were successful. The negative-pressure device showed good stone retention capabilities, with no observed stone migration. We did not observe any major complications. The stone-free rate was 97.44% (76/78), demonstrated on plain radiography of the kidney-ureter-bladder on the first postoperative day. The stone-free rate after 1 month was 100%. CONCLUSIONS: The negative-pressure ureteroscopic lithotripsy is easy and safe management for the ureteral stones. It might reduce the risk of stone fragment retropulsion, improve surgical vision, shorten the operative time, and decrease the renal pelvic pressure.

Enucleation of the prostate: An anatomical perspective.

Among transurethral surgery for benign prostatic hyperplasia (BPH), anatomical endoscopic enucleation of the prostate (AEEP) differs from conventional transurethral surgery as it adopts the same enucleation principle as open surgery. AEEP is known as an effective and safe surgical method. However, the learning curve is steep because the surgical anatomy is different from that of conventional transurethral surgery. If information on surgical anatomy related to enucleation is enriched and surgical standardisation is achieved, the learning curve will be shortened and AEEP will become more widespread. The concept of AEEP has been developed based on the surgical techniques obtained from holmium laser enucleation of prostate (HoLEP). The original surgical technique of HoLEP is a three-lobe technique. At the 12 o'clock position at the prostatic apex, the boundary of the prostate capsule is unclear. Separating anterior prostatic tissue from the prostatic capsule while preserving the sphincter in the apical area is one of the biggest challenges in AEEP. During the AEEP procedure, an accurate understanding of the surgical anatomy of the capsular plane, bladder neck, apical sphincteric area and blood vessels is important. In this article, literature on the anatomy related to enucleation in AEEP, mainly HoLEP, is reviewed and discussed.

Endoluminal release of ureteral ligature after hysterectomy.

Iatrogenic ureteral injury is a well-recognized complication of abdominal total hysterectomy. We report a case of a 57-year-old female who underwent abdominal total hysterectomy for a uterine myoma and experienced severe right flank pain postoperatively. The imaging study displayed an obstruction of the right distal ureter. Under ureteroscopy, an extraluminal ligature was released with a holmium:yttrium-aluminum-garnet laser. The stenotic segment was immediately relieved. Two months later, the intravenous urogram illustrated patency of the distal ureter with regression of right hydronephrosis. There was no recurrent hydronephrosis during 1 year of follow-up.

Efficacy and safety of semirigid ureteroscopy combined with holmium: YAG laser in the treatment of upper urinary tract calculi: Is it a good alternative treatment option of flexible ureteroscopy for developing countries?

OBJECTIVE: To assess the success rates of endoscopic management of upper ureteral stones using semirigid ureterorenoscopy and holmium: YAG laser lithotripters. METHODS: A total of 74 patients with an established diagnosis of upper ureteric stone and scheduled for endoscopic ureteral stone treatment were retrospectively evaluated. Failure was defined as the inability to contact or fragment the stone, migration of the stone into the renal pelvis and difficulty in visualizing the stone for the second time. Success rates and influencing factors as for stone-free state were investigated. RESULTS: Mean age of our patients was 45.99±15.00 (range: 24-82) years. In 14 of 74 patients procedural failure was observed. Double J stents were implanted in 65 % of the patients and ureteral catheterization was performed on 20% of them. The total success rate was 81.1 %. Major complication rate was 1.1 percent. Factors effecting the success rate as gender, age, body mass index, grade of hydronephrosis and stone size were evaluated and only age was found to be statistically significant. CONCLUSIONS: Despite some potential risks, semirigid ureterorenoscopic stone extraction and holmium: YAG laser lithotripters are still safe and effective treatment alternatives for management of upper ureteral stones.

In vitro fragmentation efficiency of holmium: yttrium-aluminum-garnet (YAG) laser lithotripsy--a comprehensive study encompassing different frequencies, pulse energies, total power levels and laser fibre diameters.

OBJECTIVE: To assess the fragmentation (ablation) efficiency of laser lithotripsy along a wide range of pulse energies, frequencies, power settings and different laser fibres, in particular to compare high- with low-frequency lithotripsy using a dynamic and innovative testing procedure free from any human interaction bias. MATERIALS AND METHODS: An automated laser fragmentation testing system was developed. The unmoving laser fibres fired at the surface of an artificial stone while the stone was moved past at a constant velocity, thus creating a fissure. The lithotripter settings were 0.2-1.2 J pulse energies, 5-40 Hz frequencies, 4-20 W power levels, and 200 and 550 µm core laser fibres. Fissure width, depth, and volume were analysed and comparisons between laser settings, fibres and ablation rates were made. RESULTS: Low frequency-high pulse energy (LoFr-HiPE) settings were (up to six times) more ablative than high frequency-low pulse energy (HiFr-LoPE) at the same power levels (P < 0.001), as they produced deeper (P < 0.01) and wider (P < 0.001) fissures. There were linear correlations between pulse energy and fragmentation volume, fissure width, and fissure depth (all P < 0.001). Total power did not correlate with fragmentation measurements. Laser fibre diameter did not affect fragmentation volume (P = 0.81), except at very low pulse energies (0.2 J), where the large fibre was less efficient (P = 0.015). CONCLUSIONS: At the same total power level, LoFr-HiPE lithotripsy was most efficient. Pulse energy was the key variable that drove fragmentation efficiency. Attention must be paid to prevent the formation of time-consuming bulky debris and adapt the lithotripter settings to one's needs. As fibre diameter did not affect fragmentation efficiency, small fibres are preferable due to better scope irrigation and manoeuvrability.