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Introduction: There are two main mechanisms of stone ablation with long-pulsed infrared lasers: photothermal and photomechanical. Which of them is primary in stone destruction is still a matter of ...

Ureteral stent encrustation is sometimes encountered, especially in cases in which a ureteral stent has been forgotten. An 84-year-old female patient with malignant myeloma underwent metallic ureteral stent insertion to treat malignant ureteral obstruction. At the time of scheduled ureteral stent exchange, the stent was heavily encrusted and could not be removed on either side. We performed endoscopic lithotripsy to remove the encrusted ureteral stents. The bilaterally encrusted metallic ureteral stents were successfully removed using Ho:YAG laser lithotripsy after inserting another ureteral stent placement besides the encrusted metallic ureteral stents.

To evaluate calyceal irrigation fluid temperature changes during flexible ureteroscopic Ho:YAG laser lithotripsy. Between May 2019 and January 2020, patients with kidney stones undergoing flexible ureteroscopic Ho:YAG laser lithotripsy were enrolled. A K-type thermocouple was applied for intraoperative temperature measurement. Laser was activated at different power (1 J/20 Hz and 0.5 J/20 Hz) and irrigation (0 ml/min, 15 ml/min and 30 ml/min) settings, temperature–time curve was drawn and time needed to reach 43 °C without irrigation was documented. Thirty-two patients were enrolled in our study. The temperature–time curve revealed a quick temperature increase followed by a plateau. With 15 ml/min or 30 ml/min irrigation, 43 °C was not reached after 60 s laser activation at both 1 J/20 Hz and 0.5 J/20 Hz. At the power setting of 1 J/20 Hz and irrigation flow rate of 15 ml/min, the temperature rise was significantly higher than other groups. Without irrigation, the time needed to reach 43 °C at 1 J/20 Hz was significantly shorter than that at 0.5 J/20 Hz (8.84 ± 1.41 s vs. 13.71 ± 1.53 s). Ho:YAG laser lithotripsy can induce significant temperature rise in calyceal fluid. With sufficient irrigation, temperatures can be limited so that a toxic thermal dose is not reached, when irrigation is closed, the temperature increased sharply and reached 43 °C in a few seconds.

Aim: To test the characteristics of a hybrid laser (combination of a thulium and blue diode laser) vs thulium and Ho:YAG lasers regarding soft tissue ablation. Methods: Tissue samples of fresh nonf...

The aim of this study was to summarize the recent innovations of the holmium laser with special respect to lithotripsy. Therefore, we reviewed and discussed the most recent and pivotal publications on this topic.The current literature underlines Holmium:yttrium-aluminium-garnet (Ho:YAG) lithotripsy as a well tolerated and efficient method to treat urinary calculi. Because of modifiable adjustments of pulse energy, pulse frequency, and pulse length, especially with newer generations of holmium lasers, urologists can accurately choose between the 'fragmentation' and 'dusting' technique with its alterations. Recently, the 'Moses mode' as a new feature incorporated in the Lumenis Pulse P120H holmium laser showed less retropulsion with higher rates of stone ablation because of an improved energy transmission from the laser fiber towards the targeted calculus in in-vitro studies.Based on technological developments, Ho:YAG laser lithotripsy has become more efficient in reducing retropulsion and increasing stone ablation volume. However, despite its widespread use as a lithotripter, a newly developed thulium fiber laser, which has already shown promising results in experimental studies, could become an alternative in future practice.

For the aging population, surgery for lumbar spinal canal stenosis (LSCS) requires minimally invasive procedures. Recently, trans-sacral epiduroscopic laser decompression for lumbar disc herniation has been reported with good results. In this study, we devised a new method to perform trans-sacral epiduroscopic laser ablation of the ligamentum flavum (LF), known to be the major cause of LSCS. Using a live pig, this study aims to evaluate the efficacy, safety, and drawbacks of this procedure.Using an epiduroscope, we observed intra-spinal canal structures and then examined the feasibility and problems of a decompression procedure to ablate the LF using holmium:YAG (Ho:YAG) laser. The pig was observed for behavioral changes and neurological deficits after the procedure. Histological analysis was performed to evaluate the amount of tissue ablation and damage to surrounding tissues.Although it was possible to partially ablate the LF using the Ho:YAG laser under epiduroscopy, it was difficult to maintain a clear field of view, and freely decompressing the target lesion has been a challenge. After the first two experiments, the pig neither showed abnormal behavior nor any signs of pain or paresis. However, in the third experiment, the pig died during the operation. On autopsy, no thermal or mechanical injury was noted around the ablated site, including the dura mater and nerve root. Histological analysis showed that the LF and lamina were deeply ablated as the laser power increased, and no damage was noted on surrounding tissues beyond a depth of 500 μm.Although Ho:YAG laser could ablate the ligamentum and bone tissues without causing damage to surrounding tissues, it was difficult to completely decompress the LF under epiduroscopy. This method is a potentially highly invasive procedure that requires caution in its clinical application and needs further improvement in terms of the instruments and techniques used.

Ureteroscopic stone dusting utilizing a high power laser system has become more popular in recent years due to the production of finer debris/remains, lower retropulsion, and shorter operation time (potential to avoid the routine use of post-operative stenting and the use of ureteral access sheaths (UAS)). Typical dusting settings are lower pulse energy (as low as 0.2 J) with higher frequency (up to 80 Hz). This study investigates the best dusting mode to produce a high ablation rate and low retropulsion. The objective of the study was to evaluate the performance of a concept optimal dusting mode. In vitro investigations of Ho:YAG laser-induced stone ablation and retropulsion were performed with a benchtop model in a highly reproducible manner using a hands-free setup and measuring the effects of multiple pulses. A systematic comparison of the performance (ablation and retropulsion) of the concept optimal dusting mode against a reference laser dusting mode was conducted. Within this benchtop test model, the optimal dusting mode had a relatively fast ablation rate while keeping retropulsion low.

The Ho:YAG laser has been the favored lithotripter for treating urinary calculus since shortly after its introduction in the 1990s because it can fragment all calculus compositions and produces less calculus migration (retropulsion) during treatment than the short-pulsed lasers. Although the lamp-pumped Ho:YAG laser has been commercialized for ureteroscopic laser lithotripsy (URS) for almost 25 years, the lamp-pumped laser rod's transient thermal behavior under an out-of-control lamp discharge has not been reported. A safety question arises: how big is the laser output under an out-of-control lamp discharge? The objective of this study is to simulate the transient thermal behavior of the lamp-pumped laser rod. The temperature profile inside the laser rod is transformed into an equivalent thermal lens, and from the time interval of the variation of the thermal lens between the lasing threshold and the maximum value of the stable region, we can estimate the level of the laser output. The simulation tool used for this study is the Ansys Fluent. The transient thermal behavior of the lamp-pumped laser rod under an out-of-control lamp discharge was reported. Optimization of the pumping pulse for the desired laser output pulse is for future study.

Lumbar foraminal stenosis has been identified as a common cause of radicular symptoms and can lead to persistent pain after prolonged treatment. A facet-preserving microdecompression technique using a paraspinal approach has been considered the gold standard for the surgical treatment of lumbar foraminal or far lateral stenosis but has been associated with postoperative leg pain or dysesthesia. More recently, authors have reported the use of a technique known as endoscopic foraminal discectomy with or without foraminotomy for the treatment of foraminal stenosis. Recent advancement in endoscopic devices as well as the use of a side-firing, holmium:yttrium-aluminum-garnet (Ho:YAG) laser has further the surgeon to treat foraminal stenosis more quickly and with less complications.

Posterior endoscopic cervical foraminotomy (PECF) is one of the minimally invasive procedures that solve the lateral pathology of cervical spine that can cause radiating pain. In the past, it was performed as an operation to enlarge the incision, but due to the recent development of the endoscope, effective treatment with minimal incision has become possible. At the same time, with the development of lasers along with endoscopy, these treatment techniques are creating a better prognosis through more sophisticated and effective methods. It is important to understand in which cases these techniques are performed properly and how to safely and effectively perform these techniques.

The main advantage of endoscopic surgery is that it minimizes skin incision, preserves bone and muscle tissue as much as possible, and has less bleeding than incision surgery. Laser has been used in various medical fields since it was discovered in 1958. The authors describe the method of discectomy using Ho:YAG laser after transforaminal approach in paramedian disc herniation and intend to review literature.

Purpose: To evaluate the efficacy of new super pulse thulium fiber laser (SP TFL) and compare it with holmium laser for ureterolithotripsy. Patients and Methods: A total of 174 patients with solita...

Background Treatment of broncholithiasis is complex, especially in the case of a large or transbronchial broncholith. Holmium-yttrium aluminum garnet (Ho:YAG) laser lithotripsy may be a useful treatment in broncholithiasis; however, as it is not yet common practice, the optimal parameters are unknown. Methods We performed a single-center retrospective analysis of the clinical data of 13 broncholithiasis patients who underwent Ho:YAG laser lithotripsy from May 2012 to October 2018. Results For the 13 patients (2 males and 11 females), Ho:YAG laser lithotripsy was performed 17 times, in total. All procedures were performed under general anesthesia with rigid bronchoscopy. We initially set the Ho:YAG laser to a pulse frequency of 5 Hz and a pulse energy of 0.8 J, gradually increasing these as required. The pulse frequency range we employed was 5–15 Hz, and the pulse energy range was 0.8–1.6 J. All broncholiths were successfully extracted after lithotripsy, and all symptoms improved. Hemoptysis, bronchial esophageal fistula, and pneumonia were the most common complications; however, there were no long-term complications. Conclusions Ho:YAG laser lithotripsy is an effective and safe treatment for broncholithiasis, over a long-term follow up.

BACKGROUND AND OBJECTIVES To report the first experiences with a newly available Ho:YAG laser system for the treatment of salivary stones. STUDY DESIGN/MATERIALS AND METHODS A retrospective study in a tertiary referral center was conducted. Patients diagnosed with sialolithiasis were treated in Erlangen using the Calculase III™ Ho:YAG laser (Karl Storz, Tuttlingen, Germany). Preset parameters had a frequency of 4 Hz and energy of 0.8-1.2 J, resulting in 3.2-4.8 W. Following total fragmentation, one to two serial sialendoscopies were performed to achieve complete fragment clearance. RESULTS A total of 55 stones in 49 patients were treated; 17 stones in 15 submandibular glands and 38 in 34 parotids. In total, 61 laser lithotripsies (range 1-3 per stone) were performed using various modes (long, short, and burst) and with preset parameters of 4 Hz and energy of 0.8-1.2 J, resulting in effective power of 3.2-4.8 W. Complete fragmentation was achieved in all the accessible stones. Sialendoscopes, fibers, or the mode used had no significant influence on success rates. A multimodal therapy concept was employed to treat stones in 12.24% of the cases; 95.92% of the patients were ultimately stone-free, and all became symptom-free. All glands were preserved. CONCLUSIONS The new Calculase III™ Ho:YAG laser was effective in the treatment of sialolithiasis with no increased risk of complications in the patients or damage to the sialendoscopes. Clinical factors such as the type of gland involved, or the location and size of stones had a greater impact on success rates than the technical or preset parameters. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

INTRODUCTION AND OBJECTIVE:Holmium: YAG (Ho:YAG) laser is currently the standard for lithotripsy. Recently, Superpulsed Thulium Fiber Laser (TFL) has been evaluated as an alternative for lithotrips...

Introduction: Besides extracorporeal shockwave lithotripsy, semi-rigid ureteroscopy (URS) has become an equal therapy of choice for the treatment of most distal ureteric stones. Before the wide availability of laser lithotripsy as a tool for stone fragmentation, pneumatic lithotripsy was, and still is, widely used. In a country like Iraq, availability and affordability are the huge questions asked. Besides the capital investment for a laser machine, the pneumatic device is reusable, whereas the laser fibers are limited in their reusability. This makes pneumatic lithotripsy a more cost-effective option, at least in our setting. The question remains whether both options, compared in our setting with our limited resources, are equally effective and beneficial to our patients. Patients and Methods: Fifty patients were included in our prospective study who underwent URS for the treatment of a distal ureteric stone. Half each (n = 25) underwent pneumatic (group A) or laser lithotripsy (group B). Inclusion criteria were a single distal ureteric stone measuring 7–20 mm in largest diameter, no anatomical abnormality, age >18 years, and an unsuccessful attempt of medical expulsion therapy. Patients with signs of urinary infection and pregnant women were excluded. All patients were operated upon under spinal anesthesia. Data recorded included operation time, stone size, type of scope and lithotripter, complications, hospital stay, and stone-free rate. Results: Both groups did not show statistically significant differences in patient demography, stone size, operation time, complications, and stone-free rates (p > 0.05). Conclusion: Both pneumatic and Ho:YAG laser lithotripsy are equally effective and safe in treating distal ureteric stones in our setting. If the cost and availability of laser treatment is an issue, pneumatic lithotripsy is a viable and more cost-effective option.

For delivery of high power Ho:YAG laser, a fiber with 7 tubes and a core of 40µm was designed. Also we designed a coupling structure and a waterproof structure at either end of fiber. © 2020 The Author(s)

Introduction: Holmium:yttrium–aluminium–garnet (Ho:YAG) is currently the gold standard for lithotripsy for the treatment of all known urinary stone types. Stone composition and volume are major determinants of the lithotripsy. This in vitro study evaluated the required energy to ablate 1 mm3 of various stone types with different laser settings using Ho:YAG. Methods: 272 µm core-diameter laser fibers (Boston Scientific©) were connected to a 30 Watt MH1 Ho:YAG generator (Rocamed®). An experimental setup consisting of immerged human stones of calcium oxalate monohydrate (COM), uric acid (UA) or cystine (Cys) was used with a single pulse lasing emission (0.6/0.8/1 J), in contact mode. Stones were dried out before three-dimensional scanning to measure ablation volume per pulse (AVP) and required energy to treat 1 mm3 (RE). Results: All settings considered, ablation volumes per pulse (AVP) for COM were significantly lower than those for UA and Cys (p = 0.002 and p = 0.03, respectively), whereas AVP for Cys was significantly lower than those for UA (p = 0.03). The mean REs at 0.6 J pulse energy (PE) for COM, Cys and UA were 34, 8.5 and 3.2 J, respectively The mean REs at 1 J PE for COM, Cys and UA were 14.7, 6.4 and 2 J, respectively. At 0.6 J PE, RE for COM was more than tenfold and fivefold higher than those for UA and Cys, respectively. Conclusion: This in vitro study shows for the first time a volumetric evaluation of Ho:YAG efficiency by the ablation volume per pulse on human stone samples, according to various pulse energies. The REs for COM, UA and Cys should be considered in clinical practice. In vivo imaging was performed at Life Imag-ing Facility of Paris Descartes University (Plateforme Imageries du Vivant), supported by France Life Imaging (grant ANR-11-INBS-0006) and Infrastructures Biologies-Santé.

This chapter provides an in-depth summary of the application of the holmium:YAG laser in ureteroscopy. First, the basic physics of laser lithotripsy is reviewed. Laser generators and the peculiarities of laser fibers are then discussed, with a special focus on their application in flexible ureteroscopy. Finally, some of the studies evaluating the outcomes and safety profile of holmium laser lithotripsy are reviewed.

The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 µm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL − 1.9 °C; for Ho:YAG laser − 2.8 °C at 60 s). SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.

Background: There are limited number of studies comparing the results of Holmium:YAG laser lithotripsy (LL) and pneumatic lithotripsy (PL) for pediatric ureteral stones. Objectives: To perform a comparative analysis of LL and PL in the management of ureteral stones in children and adults. Study design: Ninety-eight children (56 boys and 42 girls) and 623 adults (360 men and 263 women), who were treated for ureteral stones at our clinic between 2017 and 2019, were the subjects of this study. Patients were grouped according to their age as group 1 (n:98, pediatric [

INTRODUCTION AND OBJECTIVES:Ho:YAG laser is the “gold standard” in the treatment of lower and upper urinary tract stones. Ho:YAG laser with Moses Technology is new technology to reduce retropulsion...

INTRODUCTION AND OBJECTIVES:As its wavelength of 1940nm more closely matches the water absorption peak of electromagnetic radiations, the SuperPulsed Thulium Fiber Laser should be more efficient th...

WOS: 000410748000009 PubMed ID: 27761633 To establish if a retropulsion prevention device for ureteral stones equalizes surgical success and push-back rates of Ho:YAG laser and pneumatic lithotripters for upper ureteral stones. Patients with upper ureteral stones (n = 267) were treated endoscopically at the Department of Urology between April 2014 and December 2015. Patients were randomly assigned to pneumatic and Ho:YAG laser lithotripters as group-1 and group-2, respectively. Lithotripsy was performed with Stone Cone(TM) in both groups. The surgical success rate on the first postoperative day was 81.5 % (n = 106) and 90.6 % (n = 116) for group-1 and group-2, respectively, and the difference between the groups was statistically significant (p < 0.05). The relation between stone size and surgical success was statistically significant for both groups (p < 0.01). Surgical success for the stones closer than 2 cm to the UPJ was 23.1 % for the pneumatic group versus 64 % for the laser group (p < 0.01). Lithotripsy time was significantly longer in group-2 (16.48 +/- 4.74 min) than group-1 (12.24 +/- 3.95 min) (p < 0.01). Ho:YAG laser lithotripsy is more successful than pneumatic lithotripsy for upper ureteral stones and a retropulsion prevention device does not equalize the surgical success of Ho:YAG laser and pneumatic lithotripters for upper ureteral stones on the first postoperative day and one month after surgery. Although the success rate of the first month after surgery is higher in group-2, the difference is not statistically significant. Academical Study Supporting Unit of Ahi Evran University [PYO-TIP.4005.13.005] This study was supported by the contribution of the Academical Study Supporting Unit of Ahi Evran University by the number of PYO-TIP.4005.13.005.

Liquid-assisted hard tissue ablation by infrared lasers has extensive clinical application. However, detailed studies are still needed to explore the underlying mechanism. In the present study, the dynamic process of bubble evolution induced by Ho:YAG laser under water without and with bone tissue at different thickness layer were studied, as well as its effects on hard tissue ablation. The results showed that the Ho:YAG laser was capable of ablating hard bone tissue effectively in underwater conditions. The penetration of Ho:YAG laser can be significantly increased up to about 4 mm with the assistance of bubble. The hydrokinetic forces associated with the bubble not only contributed to reducing the thermal injury to peripheral tissue, but also enhanced the ablation efficiency and improve the ablation crater morphology. The data also presented some clues to optimal selection of irradiation parameters and provided additional knowledge of the bubble-assisted hard tissue ablation mechanism.

Background and objective: Endoscopic laser lithotripsy is the preferred technique for minimally invasive destruction of ureteral and kidney stones, and is mostly performed by pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser irradiation. The absorbed laser energy heats the water creating a vapor bubble which collapses after the laser pulse, thus producing a shock wave. Part of the laser energy strikes the stone through the vapor bubble and induces thermomechanical material removal. Aim of the present study was to visualize the behavior and the dynamics of the cavitation bubble using a specially developed ultra-short-time illumination system and then to determine important characteristics related to clinically used laser and application parameters for a more detailed investigation in the future. Materials and methods: In accordance with Toepler’s Schlieren technique, in the ultra-short-time-illumination set-up the cavitation bubble which had been induced by Ho:YAG laser irradiation at the fiber end, was illuminated by two Q-switched lasers and the process was imaged in high contrast on a video camera. Cavitation bubbles were induced using different pulse energies (500 mJ/pulse and 2000 mJ/pulse) and fiber core diameters (230 μm and 600 μm) and the bubble dynamics were recorded at different times relative to the Ho:YAG laser pulse. The time-dependent development of the bubble formation was determined from the recordings by measuring the bubble diameter in horizontal and vertical directions, together with the volume and localization of the center of the bubble collapse. Results: The results show that the bubble dynamics can be visualized and studied with both high contrast and high temporal resolution. The bubble volume increases with pulse energy and with fiber diameter. The bubble shape is almost round when a larger fiber core diameter is used, and elliptical when using a fiber of smaller core diameter. Moreover, the center of the resulting bubble is slightly further away from the fiber end and the center of the bubble collapse for a smaller fiber core diameter. Conclusion: The experimental set-up developed gives a better understanding of the bubble dynamics. The experiments indicate that the distance between fiber tip and target surface, as well as the laser parameters used have considerable impact on the cavitation bubble dynamics. Both the bubble dynamics and their influence on the stone fragmentation process require further investigation.

INTRODUCTION AND OBJECTIVE:Small core (240 - 300μm) fibers are used for Ho:YAG laser lithotripsy. The SOLTIVE SuperPulsed Thulium Fiber (SPTF) Laser permits the use ≤ 200μm core sized fibers. We ev...

Background To determine the most efficacious setting of Holmium:yttrium-aluminum-garnet (Ho:YAG) laser with a maximum power output of 120 W with in vitro phantom-stone dusting technique. Methods A laser was used to treat two 4 × 3 × 3 mm3 sized phantom stones in 5 mL syringes with 1 mm-sized holes at the bottom. According to the pulse width (short 500, middle 750, long pulse 1000 μsec), maximal pulse repetition rates from 50 to 80 Hz were tested with pulse energy of 0.2, 0.4, 0.5, and 0.8 J. Six times of the mean dusting times were measured at each setting. Dusting was performed at continuous firing of the laser until the stones become dusts

Introduction: Presently, different holmium: yttrium aluminum garnet (Ho:YAG) laser calibers are used for endoscopic stone treatment, which include 200, 365, 500 and 1000 Mm fibers. Currently, there are not enough studies to compare the performance of these fibers. In this retrospective investigation, we compared the outcome of 200, 365 and 500 Mm fibers of Ho:YAG laser in transurethral lithotripsy of ureteral stone. Methods: From January 2016 to June 2017, 74 subjects with mean age of 35.3 ± 5.6 were randomly allocated to 3 groups according to the caliber of laser, 200, 365 and 500 Mm for transurethral lithotripsy. The main purpose of this investigation was to evaluate mean operation time (MOT), stone free rate (SFR) and complications. Results: MOT and SFR were significantly different in 500 Mm laser caliber (P=0.046, P=0.029, respectively). There was no remarkable difference between the 3 groups in this regard. Conclusion: Based upon our data, the clinical potency of the Ho: YAG laser was great in all 3 fiber calibers. The most important results of this comparison were the significantly higher SFR with increased laser caliber.

Introduction: The Ho:YAG-Laser is categorized as a potentially dangerous lithotripsy device (DIN: Class 4) for perforation which is mainly caused by the photonic energy the laser emits. Long time complications like ureteral strictures seem to be directed by thermal and mechanical injury. In this study different energy settings a) are being investigated, a DJ (double J stent) is placed beside the laser to simulate a therapy of a forgotten stent with reduction of the lumen b) due to the volume exploitation of the DJ, and direct contact between the laser fiber and the DJ in the ureter c) is simulated during laser exposure. Materials and Methods: We used the Ho:YAG-laser (Vera PulseTM, Coherent, Santa Clara USA) with a 365 μm diameter laser fiber. The settings of the laser were 0.6 J and 1 J pulse energy with a frequency of 5 Hz. The experimental setup was closely aligned with the clinical situation. The tip of the thermometer was attached inside the catheter through a puncture. The laser fiber was guided by means of a rigid URS video device (11.5 Ch). We had four different settings for a), b) and c) during the measurement: 1) Distance of 0.5 cm between the laser and the thermometer; without irrigation, 2) Distance of 0.5 cm between the laser and the thermometer; with irrigation, 3) Distance of 1 cm between the laser and the thermometer; without irrigation, 4) Distance of 1 cm between the laser and the thermometer; with irrigation. Results: The temperature in an empty ureter rises approximately by 5°C, when the laser energy is increased from 0.6 J to 1 J. When a DJ is inserted in the artificial ureter there is surprisingly almost no difference in the maximum temperature between the lower energy level (0.6 J) and the high energy level (1 J). However the time needed to reach the maximum temperature is noticibly less when using high energy levels. The reduction involume based on the placement of the DJ leads to a higher maximum temperature for the low energy setting. The third setting with direct laser fiber contact with the DJ produces the highest temperatures of up to 55°C. We think there must be a melting or burning of the DJ which leads to a temperature rise. Bubble formation was a sign of heating in the ureter in every setting without irrigation. A temperature fall off with increasing distance between the laser fiber and the thermometer is noticable when measuring without irrigation. Conclusion: There is no relevant heating with irrigation. Direct contact between the laser fiber and the DJ seems to evoke additional heating because of melting or underwater burning of the DJ. The maximum temperatures reached without irrigation are limited to a relatively small volume since the is a noticable temperature fall of when increasing the distance between the laser fiber and the thermometer.

Introduction: The laser is a high energy instrument which can melt metals like nitinol. So it is very important to know under which conditions it is dangerous to perform an endourologic lithotripsy. We measure the temperature increase during laser exposure in an underwater in-vitro ureter model. For comparison, temperatures with and without irrigation and with different distances from the laser fiber to the thermometer are measured. Materials and Methods: We used the Ho:YAG-laser (Vera PulseTM, Coherent) with a 365 μm laser fiber. The settings of the laser were 0.6 J with a frequency of 5 Hz which is the minimum setting for that type of laser. The experimental setup was closely aligned with the clinical situation. A metal container was filled with 0.9% sodium chloride (NaCl) solution (Temp. 36.8°) and a catheter with an inner diameter of 4 mm was attached to the rim of the container. The tip of the thermometer was attached inside the catheter through a waterproof hole. The laser fiber was guided by means of a rigid URS video device (11.5 F). We had four different settings during the measurement: 1) Distance of 0.5 cm between the laser and the thermometer; without irrigation, 2) Distance of 0.5 cm between the laser and the thermometer; with irrigation, 3) Distance of 1 cm between the laser and the thermometer; without irrigation, 4) Distance of 1 cm between the laser and the thermometer; with irrigation. Results: The maximum overall temperature was recorded in the 1) and 3) setting, both featuring no irrigation. The maximum temperature was ~50°C in both settings, with the 1) setting reaching the maximum temperature after 50 seconds and hence approximately twice as fast as the 3) setting. During measurements with a NaCl solution flow we couldn’t detect any noticeable increase in temperature, neither at short nor at long distance between the laser fiber and the thermometer. Conclusion: There is a relevant heating in the ureter beside an endourologic lithotripsy. In our model we could reproduce a maximum heating until ~50°C without irrigation and no heating with irrigation. Without irrigation there is a relevant bubble formation which should be an indicator for the surgeon to stop lithotripsy due to a temperature increase which could harm surrounding tissue.

The aim was to compare pneumatic and holmium:yttrium-aluminum-garnet laser in the treatment of impacted ureteral stones with different locations and to identify the risk factors for complications. Between March 2005 and November 2012, a total of 230 patients underwent ureteroscopic lithotripsy for impacted stones. Of the patients, 117 had pneumatic and 113 had laser lithotripsy for the fragmentation of the stones. Treatment outcomes based on evidence of being stone free were evaluated. Preoperative, operative, and postoperative follow-up findings were analyzed and compared. There was a difference between the two groups according to overall stone clearance rate (93.8% vs. 80.3%, p = 0.002). There was no statistically significant difference for distal location between the laser and pneumatic groups (96.8% vs. 91.7%, p =0.288). For 10 patients with intrarenally migrated stones who were managed with flexible ureterorenoscopy in the same session, laser lithotripsy was more successful than pneumatic for proximal ureteral stone (94.4% vs. 67.9%, p = 0.007). The overall complication rate was 26.1%. There was no statistically significant difference between the two groups (29% vs. 23%, p = 0.296). Multivariate logistic regression analysis revealed that the proximal location was a statistically significant parameter for the occurrence of complications in both groups (p = 0.001 for PL, p = 0.004 for laser). The pneumatic and holmium:yttrium-aluminum-garnet laser lithotripsy are effective in the treatment of distal impacted stones. Both treatments with semirigid ureteroscopy are acceptable for proximal impacted ureteral stones, but holmium laser lithotripsy has an advantage of use with flexible ureteroscope for intrarenally migrated stone.

In this work, we demonstrate the use of 2.12-μm Ho:YAG laser with a deviated-firing fiber for laser ablation on chicken tissues. The tissue ablation tests were conducted under non-contact and contact conditions. The thermal damage and ablation efficiency made by the fiber on the tissue were quantitatively analyzed and compared. It is found that, the ablation threshold is lower and ablation is more efficient under the non-contact mode, in which the fiber device is kept at a small distance of 0.5–1.0 mm from the target tissue. This can be attributed to amber space between the fiber and the tissue that allows the ejection of ablation debris and vapor from the ablation zone. This ensures better transmission of laser energy from the fiber device to the target tissue. Such design offers better ablation efficient and enhances the service life of the medical fiber device.

Ureteroscopy in children, in pregnancy, and in patients with reno-ureteral malformations present certain particular aspects regarding the diagnostic algorithm, operative technique, and postoperative follow-up. The difficulties regarding retrograde endoscopic treatment in these cases derive from the particular anatomic aspects, as well as the characteristics that limit the use of some types of common instruments during ureteroscopy in the “index patient,” as defined by the EAU/AUA Consensus.

The purpose of the study was to review the existing literature on holmium:yttrium–aluminum–garnet laser lithotripsy regarding lithotripter settings and laser fibers. An online search of current and past peer-reviewed literature on holmium laser lithotripsy was performed on several databases, including PubMed, SciElo, and Google Scholar. Relevant studies and original articles about lithotripter settings and laser fibers were examined, and the most important information is summarized and presented here. We examine how the choice of lithotripter settings and laser fibers influences the performance of holmium laser lithotripsy. Traditional laser lithotripter settings are analyzed, including pulse energy, pulse frequency, and power levels, as well as newly developed long-pulse modes. The impact of these settings on ablation volume, fragment size, and retropulsion is also examined. Advantages of small- and large-diameter laser fibers are discussed, and controversies are highlighted. Additionally, the influence of the laser fiber is examined, specifically the fiber tip preparation and the lithotripter settings’ influence on tip degradation. Many technical factors influence the performance of holmium laser lithotripsy. Knowing and understanding these controllable parameters allows the urologist to perform a laser lithotripsy procedure safely, efficiently, and with few complications.

Objectives: To study the treatment of ureteric stones by HO:YAG laser lithotripsy and pneumatic lithotripsy and to evaluate the results of the two treatment modalities to assess effectiveness and complications. Materials and Methods: Over 1-year period, a total of 79 patients with 82 ureteral stones were randomized into two groups. In group 1 (39 cases with 41 ureteral stones) ureteroscopic HO:YAG laser lithotripsy was performed using a rigid 8 Fr-ureteroscope (LL group). In group 2 (40 cases with 41 ureteral stones) pneumatic lithotripsy was performed in like manner. Efficacy safety and complications in both groups were analyzed. Results: A total of 79 patients with 82 calculi were treated. Two cases in LL group and one in PL group had bilateral ureteral stones. Mean stone size was 12.07 mm in LL group and 10.2 mm in PL group. Stones located in lower ureter in 30 cases on LL group and 29 cases in PL group. Proximal migration of stone occurred in 1 case on LL group and in 3 cases on PL group. Successful fragmentation occurred in 37 cases on LL group and in 30 cases on PL group. Stone-free rate after 1 month in the base of Kidney Ureter Bladder (KUB) and sonography was 95% in LL group and 80.5% in PL group. Ureteral perforation, urinoma, and urosepsis were not seen in both groups. Conclusion: HO:YAG laser has advantages over PL in high efficacy of stone fragmentation and a low-retrograde migration of ureteral stone treatment. Other complication of ureteral stone treatment with LL and PL are the same and very rare.

This article discusses the evolution of laser-assisted disc decompression, foramenal laser endoscopic disc ablation and endoscopic foramenotomy using a Holmium:YAG laser. Advantages of using this wavelength and several techniques for its use in minimally invasive approach to the lumbar spine are reviewed. The article also discusses the current devices and delivery systems available for this application.

Purpose to test the effect of stone entrapment on laser lithotripsy efficiency. Materials and Methods Spherical stone phantoms were created using the BegoStone® plaster. Lithotripsy of one stone (1.0g) per test jar was performed with Ho:YAG laser (365µm fiber; 1 minute/trial). Four laser settings were tested: I-0.8J,8Hz; II-0.2J,50Hz; III-0.5J,50Hz; IV-1.5J,40Hz. Uro-Net (US Endoscopy) deployment was used in 3/9 trials. Post-treatment, stone fragments were strained though a 1mm sieve; after a 7-day drying period fragments and unfragmented stone were weighed. Uro-Net nylon mesh and wire frame resistance were tested (laser fired for 30s). All nets used were evaluated for functionality and strength (compared to 10 new nets). Student's T test was used to compare the studied parameters; significance was set at p < 0.05. Results Laser settings I and II caused less damage to the net overall; the mesh and wire frame had worst injuries with setting IV; setting III had an intermediate outcome; 42% of nets were rendered unusable and excluded from strength analysis. There was no difference in mean strength between used functional nets and non-used devices (8.05 vs. 7.45 lbs, respectively; p = 0.14). Setting IV was the most efficient for lithotripsy (1.9 ± 0.6 mg/s; p < 0.001) with or without net stabilization; setting III was superior to I and II only if a net was not used. conclusions Laser lithotripsy is not optimized by stone entrapment with a net retrieval device which may be damaged by high energy laser settings.

To assess the feasibility of intracorporeal lithotripsy with holmium YAG laser under sialoendoscopic guidance for sialolithiasis of Wharton's duct.Case series with planned data collection.Tertiary referral university hospital.This study was conducted on 16 patients with sialolithiasis of Wharton's duct. Diagnosis was confirmed at ultrasound examination. Patients with stones ranging from 5 to 8 mm in diameter were enrolled in the study. The selected patients underwent intracorporeal lithotripsy with holmium Yag laser under endoscopic control. Debris was removed using sialoendoscopic forceps or a wire basket during the same procedure. After a 3-month follow-up, radiological tests were rerun.Stone fragmentation was possible in all cases. All patients experienced a regular postoperative course. Postoperative ultrasound examinations revealed residual stones in 3 patients, 1 of whom was asymptomatic. Three patients complained of residual symptoms after 3 months of follow-up. These patients were treated successfully during a second sialoendoscopic procedure.In our experience, endoscopic laser lithotripsy was proved to be a feasible technique for Wharton's duct lithiasis in clinical practice.