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Introduction: Manipulation of Holmium:Yttrium–Aluminum–Garnet laser parameters such as pulse energy (PE), frequency, and duration can impact laser lithotripsy ablation efficiency. In 2017, Lumenis introduced Moses™ Technology, which uses pulse modulation to enhance the delivery of energy from fiber to stone as well as to minimize stone retropulsion. Since the introduction of Moses Technology, other companies have brought additional pulse modulation concepts to market. The purpose of this in vitro study is to compare the pulse characteristics and stone ablation efficiency of Lumenis Moses Technology with Quanta's Vapor Tunnel™. Materials and Methods: Submerged BegoStone phantoms were systematically ablated using either the Lumenis Moses Pulse 120H or the Quanta Litho 100 clinical laser system. Two PEs (0.4 and 1 J), three fiber-stone standoff distances (SDs) (0.5, 1, 2 mm), and all available pulse duration and modulation modes for each laser were tested in combination. Fiber speed was adjusted to scan across the stone surface at either 1 or 10 pulses/mm to form single pulse craters or an ablation trough, respectively. Volumes of single craters and 1 mm trough segments were imaged and quantified using optical coherence tomography. Results: Ablation volumes decreased with decreasing PE and increasing SD. Statistically significant variability was seen between pulse types (PT) at every tested parameter set. Among pulse modulation modes, Moses Distance (MD) was superior at 0.5 mm in all testing and at 2 mm in trough testing. Vapor Tunnel (VT) was superior in 2 mm single crater testing. All modulated pulses performed similarly at 1 mm. Conclusions: In this benchtop model of laser lithotripsy, stone ablation was significantly impacted by PT. MD demonstrated superior or noninferior stone ablation at most tested parameters. VT maintained its efficacy the best as SD increased. Future work should focus on the mechanistic differences of these modes relative to other traditional laser pulse modes.

Introduction: There are limited data regarding the effect of thulium laser (Tm:YAG) and holmium laser (Ho:YAG) on upper urinary tract. The aim of this study was to compare soft tissue effects of th...

Introduction and Objectives: The Moses effect (ME) was described >30 years ago during normal laser functioning in a fluid medium. Recently, a laser device equipped with a pulse-modulating system called Moses™ technology (MT; Lumenis®) was marketed for both stone lithotripsy and prostate endoscopic surgery. We aimed to perform a literature revision of ME from a historical perspective up until its present-day applications. Evidence Acquisition: A search of Medline, PubMed, and Scopus was performed to identify articles published in English within the past 30 years addressing both ME and MT in relation to their urologic applications. Relevant studies were then screened, and the data were extracted, analyzed, and summarized. The preferred reporting items for systematic reviews and meta-analysis criteria were applied. Results: ME was first described in 1986 during endovascular laser tissue ablation. During the late 1980s and the early 1990s, the interest raised around ME led to its characterization and better definition. Despite this initial interest, ME gradually disappeared from the focus of researchers and clinicians. In 2017, MT was launched on the market, although postmarketing comparative efficacy and safety data are lacking. Conclusions: Although ME had been described and characterized during normal laser functioning >30 years ago, only very recently it began to regain some consideration after the marketing of MT, whose clinical outcomes are still awaited.

Introduction: The super pulse thulium fiber (SPTF) laser has recently been acclaimed by more efficient lithotripsy activities, shorter laser, and treatment times demonstrated in preclinica...

The objective of this study was to determine the outcomes associated with the endoscopic removal of foreign bodies (such as mesh or permanent suture) in the lower urinary tract after female stress incontinence surgery with the Holmium:YAG (Ho:YAG) laser, and to systematically review the literature on this topic.A retrospective chart review of 18 consecutive women found to have mesh or suture exposure was performed. All patients underwent Ho:YAG laser ablation. A systematic review was performed to identify literature addressing the endoscopic management of mesh/suture exposure after stress incontinence surgery.Between November 2011 and February 2016, 18 women underwent Ho:YAG laser ablation of exposed mesh or suture. Presenting symptoms included lower urinary tract symptoms, pelvic pain, incontinence, or recurrent urinary tract infections. Thirteen women had a previous synthetic midurethral sling and five had a prior retropubic suspension. The median age was 58 years (interquartile range [IQR] 50-60) and median follow-up was 2 years (IQR 1-2). Four patients (22%) had residual mesh after the first procedure, requiring a repeat endoscopic procedure. Only one patient had a small amount of asymptomatic residual mesh on cystoscopy after the final procedure. Only minor postoperative complications were observed. Eight patients had stress incontinence and four underwent operative treatment for this. In our systematic review, we identified 16 case series, which described a total of 158 patients. Women most commonly presented with voiding symptoms or incontinence. Based on the synthesis of these data, repeat procedures were necessary in 16% and vesicovaginal fistula occurred in 2%. Recurrent/persistent stress incontinence was present in 20%, and of these patients, 3/4 underwent a new stress incontinence procedure.Both our case series and the systematic review of the literature demonstrated that endoscopic treatment of lower urinary tract foreign bodies after stress incontinence surgery has good success rates and minimal morbidity.

Percutaneous nephrolithotomy (PCNL) is a well established procedure and accepted as the standard of care for the treatment of large renal calculi. Since the introduction of the holmium:yttrium-aluminum-garnet (Ho:YAG) laser into clinical practice in 1990, it has been used successfully to treat various urologic conditions. Today it is the modality of choice for retrograde intracorporeal stone disintegration ureteroscopically, and has also been used successfully for PCNL. One disadvantage when using the Ho:YAG laser for disintegration of renal calculi is the need for graspers to extract fragments and the mobilization of fragments due to the lack of simultaneous suction. We present our experience with a Ho:YAG laser in combination with simultaneous suction in an in-vitro model using a new endourologic technique in comparison to conventional ultrasonic lithotripsy.

To demonstrate the validity of non-contact holmium:yttrium-aluminum-garnet laser stone fragmentation in an in-vitro model and to characterize the optimal laser settings to perform this technique.A caliceal model consisting of a glass test tube filled with 0.9% normal saline was created. Into this system, a 365-mum laser fiber was inserted after stabilization 2 mm above the surface of the stones. Laser experiments were conducted using tubes that contained four soda limestone phantoms with a total stone burden of approximately 0.2 g per tube. The laser energy was varied between 1.0 and 1.5 J, with a firing frequency of 20, 30, or 40 Hz. Ten tubes were tested at each setting combination for a duration of 2 minutes. Thus, 60 tubes were tested. The contents of each tube were filtered through a 2-mm sieve after treatment, and all remaining fragments were dried for 5 days. The fragments were weighed, and the difference from pretreatment was calculated. Differences in weights and laser settings were compared using one-tailed and two-sample t testing.Each experiment resulted in a significant decrease in stone burden from prelaser weight (all P values = 0.00). Laser settings were manipulated between combinations of 1.0 J at a frequency of 20, 30, and 40 Hz, and an energy of 1.5 J and 20, 30, and 40 Hz. This resulted in a respective mean weight loss of -42%, -58%, and -47% at 1.0 J, and -24%, -56%, and -63% at 1.5 J. The t tests were performed to detect differences between weight loss and to determine the optimal settings. Laser settings of 1.5 J and 40 Hz for 2 minutes produced the greatest mean decrease in stone burden (63%). This loss was significantly different from that of all settings at 1.0 J and the setting of 1.5 and 20 Hz (P0.05). The mean percentage weight loss for each setting was then normalized to the total energy used. Settings of 1.0 J and 20 Hz were the most efficient, with a change in weight of -18% per kJ.We duplicated the "popcorn effect" of non-contact laser use in vitro. In this model, the technique results in a significant decrease in stone burden (up to 63%) in just 2 minutes. Adequate energy and high frequency seemed to optimize the effectiveness of the method, but excessive energy and frequency produced diminishing returns.

We prospectively compared the results of the Swiss LithoClast System with the holmium: yttrium-aluminum-garnet (Ho:YAG) laser for ureteral lithotripsy for management of upper ureteral stones.Fifty patients were randomized to two groups: LithoClast classic 2 (n = 25) and Ho:YAG laser (n = 25) between January 2005 and January 2007. Procedure selection was decided by random chit allotment. All patients who successfully had ureteral dilatation (up to 10F) were included in the study. An 8/9.8F semirigid ureteroscope was used in all procedures with LithoClast 2, and either an 8F or 7F was used in patients who underwent laser lithotripsy. Patients were analyzed for fragmentation time, stone-free rate, stone up-migration, intraoperative complications, and auxiliary procedures.Average stone size was 9.63 +/- 2.46 mm2 and 10.17 +/- 2.28 mm2 with overall stone-free rates of 84% and 88% (P = 0.41), respectively, for laser and LithoClast 2 groups. Stone up-migration was 24% and 16% (P = 0.82), mean stone fragmentation time was 9.82 +/- 7.58 and 7.86 +/- 3.25 minutes (P = 0.12), and stone fragments requiring ancillary procedures were 16% and 12% (P = 0.99), respectively, in laser and LithoClast 2 groups. Postoperative hematuria (up to 72 hours) was significantly (P = 0.04) prolonged in the laser group (36%) compared with the LithoClast 2 group (8%). Three patients in the LithoClast 2 group had instrument breakage.Both Ho:YAG laser and LithoClast 2 were equally efficient in managing ureteral stones with effective stone clearance, minimum morbidity, and reduced stone up-migration.

Adoption of holmium laser enucleation of the prostate has been limited by its difficult learning curve. To enhance training, digital video clips from four procedures were captured in MPEG-2 format and compiled into a PowerPoint file with professional narration. The two surgical techniques used--the two-lobe and three-lobe methods--are described with a focus on the technical details and common mistakes.

To report on the technique and utility of the holmium: YAG laser in performing laparoscopic partial nephrectomy (LPN).Three patients with indications for LPN (complex cyst, nonfunctioning lower pole, renal mass) underwent parenchymal-sparing procedures with the Ho:YAG laser. The kidney was identified using a transperitoneal laparoscopic technique. Gerota's fascia was opened, and the renal mass/nonfunctioning lower pole was resected using the laser. Settings of 0.2 J/pulse at 60 pulses/sec and 0.8 J/pulse at 40 pulses/sec were used.All three procedures were performed successfully with minimal blood loss and without the need for hilar occlusion. Although the laser alone was hemostatic, fibrin glue was applied in two cases and oxidized cellulose in one case to reinforce the tissue against delayed bleeding. There were no perioperative complications, and all patients left the hospital within 3 days.At high power settings, the Ho:YAG laser is an effective tool for LPN. It results in good hemostasis without the need for hilar occlusion. This technique promises to facilitate the laparoscopic management of renal tumors and nonfunctioning moieties of duplicated systems.

KORKUSUZ, FEZA/0000-0001-9486-3541 WOS: 000172158300004 PubMed: 11710619 Objective: The authors performed an experimental and a prospective clinical study to evaluate the histological and magnetic resonance imaging (MRI) alterations after irradiation of meniscus using holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and InfraTome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA). Background Data: Recently, some authors reported a few cases with articular cartilage damage or paraarticular osteonecrosis following arthroscopic knee surgery in which the laser was used to assist in the treatment of meniscal pathology. Methods: Meniscus specimens in saline immersion were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 mum and pulse duration was 250 mu sec. Power settings were 1-1.5 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 2, 3.5, and 6 K joules. Eight patients with meniscal problems underwent arthroscopic partial meniscectomy using Ho:YAG laser. Total laser energy used for these surgeries was 1.5-2.5 K joules. MRI was performed preoperatively and at 6 months postoperatively. Results: At higher energy levels (more than 3 K joules), separation of the gap between the collagen fibers, and a three-dimensional dispersion in the striation were observed on electron microscopic evaluation of meniscus specimens. No patient had abnormal signals in MRI (a sign of articular cartilage damage or osteonecrosis) following arthroscopic laser surgery. Conclusion: When higher energy level is required, conventional instruments should be preferred in the treatment of meniscal lesions. Laser should be reserved for the posteriorly located and smaller meniscal lesions.

The holmium laser is a relatively new multipurpose medical laser that recently became available for use in urology. There has been considerable interest in this device, as it seems to combine the cutting properties of the carbon dioxide laser with the coagulating properties of the neodymium:YAG laser, making it particularly appealing for many surgical applications. The last decade has seen enthusiasm for the use of laser energy for the treatment of benign prostatic hyperplasia. In this article, we review the technique of Ho:YAG laser resection of the prostate, including the essential equipment and perioperative patient care.

To evaluate the safety and efficacy of holmium:YAG laser vaporization v transurethral electroresection (TURP) for benign prostatic hyperplasia.Thirty-six patients were randomized. Two laser procedures (60 to 80 W) were performed for one TURP. Symptom Score, peak flow rate, potency, and ejaculation status were measured at baseline and at 1, 3, 6, and 12 months.The mean operative time was 75 minutes for laser and 56 minutes for TURP (P = 0.0407). With a mean laser energy delivered of 103.6 kJ, hemostasis was satisfactory during vaporization. The mean catheterization time was 1.7 and 2.1 days in the laser and TURP group, respectively. For the laser and TURP groups, the mean AUA Score improved from 20 preoperatively to 7 and from 24.1 to 5, respectively, at 12 months. The mean peak flow increased from 8.4 to 19.5 mL/sec and from 7.6 to 16.8 ml/sec, respectively, at 12 months. These results are not statistically different. No significant initial dysuria occurred. No significant difference between the groups appeared in potency or ejaculatory status during the follow-up. One patient in the laser group (Day 5) and two in the TURP group (2nd and 6th month) had to undergo a second procedure to relieve obstruction.Although taking slightly longer to accomplish, holmium:YAG laser vaporization of BPH provides early results very similar to those of TURP with a shorter catheterization time and no initial dysuria or pain.

The authors review the current knowledge regarding the application of the Holmium: YAG laser for prostatectomy.Conventional surgical therapies for benign prostatic hyperplasia (BPH) are effective but associated with relatively high morbidity. Laser prostatectomy, using either Neodymium:YAG or potassium-titanyl-phosphate lasers, has emerged as a new and much safer operative approach to relieve symptoms of benign prostatic hyperplasia. However, these laser wavelengths possess key disadvantages that have limited their acceptability and dissemination in everyday urologic practice.THE authors review their own extensive experience in the development of clinical application of Holmium: YAG laser technology for prostatectomy, as well as the published reports in the current medical literature now dealing with this subject.In multiple clinical trials, Holmium:YAG laser resection of the prostate has proven efficacious in relieving symptomatic BPH. Both objective urodynamic measures of voiding outcomes and symptomatic improvement have been shown to be equivalent to standard electrocautery resection of the prostate. At the same time, these studies have demonstrated the superior safety and hemostasis of Holmium:YAG laser prostatectomy compared to electrocautery resection, similar to prior laser prostatectomy procedure. Unlike prior forms of laser prostatectomy, Holmium:YAG laser resection of the prostate acutely removes all obstructing prostate tissue, so that the postoperative catheterization requirement is typically only overnight and improvement in voiding is immediate. Current operative techniques and the latest technological developments to facilitate Holmium:YAG laser prostatectomy are described.Holmium: YAG laser prostatectomy combines the best features of prior laser prostatectomy technologies, including minimal complications and morbidity, with the efficacy and immediacy of voiding outcomes associated with conventional electrocautery resection of the prostate.

Today, the holmium:YAG laser is the gold standard in endourologic stone treatment because of its high efficacy. However, guidewires and stone-extraction tools often are close to the fiber and may be damaged accidentally by the laser. The aim of our study was to evaluate the duration of laser application required to disrupt wires at different energy settings.Two standard wires (0.035-inch guidewire and 0.025-inch hydrophilic Terumo wire) and two baskets (1.9F Nitinol tipless and 3F stone extraction) were investigated. We used a holmium:YAG laser (Auriga; Wavelight Laser Technologie AG, Erlangen, Germany) and two fibers (230 and 365 microm) at 800 and 2000 mJ and a 5-Hz pulse rate. The laser was brought into direct contact with the wires.The average time required for transection was 55 to 103 seconds for a safety wire. The Terumo wire broke after 20 to 40 seconds of direct laser application; 15 to 34 seconds was required for a Dormia basket. Thin Nitinol basket wires were disrupted after only 1 to 4 seconds. One- and two-factorial variance analysis showed a high degree of significance (P0.0001) of the energy level and type of wire.The disruption of stone-extraction tools occurs in a remarkably short time with laser exposure, especially in case of Nitinol baskets, whereas guidewires are more resistant. Attention should be paid to avoiding contact of laser energy with wires and baskets during stone fragmentation.

The holmium:YAG laser fragments stones of all compositions effectively. However, damage to ureteral guidewires by the laser has been described, including in one of our own patients, in whom such damage resulted in morbidity. The purpose of this study was to characterize the interaction of Ho:YAG energy with guidewires in vitro. Seven ureteral guidewires were tested in a waterbath. The 365-microm Ho:YAG laser fiber was placed at defined distances (0, 1, 2, 4, and 5 mm) from the guidewire. All guidewires were tested at angles of 0 degrees, 45 degrees, and 70 degrees from normal incidence. The minimum energy setting that resulted in structural damage to the guidewires was detected by endoscopic video monitoring. All guidewires were susceptible to Ho:YAG laser damage at modest energy settings. The energy required to produce visual damage varied inversely with the square of the distance of the laser fiber from the guidewire. At a distance of 5 mm, none of the guidewires was damaged, even at energy settings of 2.8 J (the maximum output from the laser). The energy required to induce guidewire damage varied with the inverse of the cosine of the incident angle. The results demonstrate that no guidewire is immune from Ho:YAG laser damage when the fiber and guidewire are in contact. Caution must be exercised when operating the Ho:YAG laser near a guidewire, and guidewire integrity should be assured by the surgeon. Generally, the energy required to induce guidewire damage exceeded lithotripsy levels at distances >1 mm and with higher incident angles, implying a reasonable margin of safety during ureteroscopy. The pattern of energy thresholds required to induce damage with respect to distance and incident angle suggests that the mechanism of Ho:YAG lithotripsy is thermal.

Lithotripsy with the pulsed-dye laser has been shown to be a safe and effective method of intracorporeal urinary stone fragmentation. Recently, a new device, the holmium: YAG laser, has been developed with both soft tissue and lithotripsy applications. We present our preliminary experience with the Ho:YAG laser for lithotripsy of urinary calculi. Ureteroscopy and lasertripsy resulted in successful fragmentation of ureteral stones in 92% of 21 patients when the laser was used alone or in combination with electrohydraulic lithotripsy. One complication directly related to the use of the laser occurred, a ureteral perforation, when the device was utilized under fluoroscopic control. In four patients undergoing percutaneous flexible nephrolithotripsy, the laser demonstrated utility in fragmenting caliceal stones remote from the nephrostomy tract. In summary, the Ho:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. The tissue effects of this device, as well as the optimal energy/pulse and frequency settings, need further evaluation in order to minimize the risks of tissue injury.

In order to evaluate the efficacy of laser-assisted disc decompression (LADD) as an alternative treatment modality for nonsequestered herniated nucleus pulposus of the lumbar spine, we use...

The holmium:YAG laser was used successfully to fragment human urinary stones of various sizes and compositions. At an energy level of 0.5 J/pulse and at a frequency of 5 Hz, lithotripsy resulted in minimal ureteral wall injury. However, increasing the amount of energy or frequency level often caused significant damage to surrounding tissue. We conclude, therefore, that when used at low power settings with care to avoid direct ureteral wall contact, holmium:YAG laser lithotripsy appears to be an effective procedure. Additional studies are necessary to accurately assess its clinical safety.

We report our experience with the holmium laser in the endoscopic management of primary obstructive megaureter (POM) in adults.From February 1997 to September 1998, three women and one man 26 to 63 years old underwent ureteroscopic endoureterotomy for POM with symptomatic vesicoureteral junction obstruction. The left ureter was more commonly affected than the right (R:L 1:3). The diagnosis of POM was based on a clinical history, intravenous urography, diuretic renography (T 1/2), and micturating cystogram. Endoureterotomy of the juxtavesical and intramural part of the ureter was performed in a retrograde fashion using the holmium laser. Incision of the subepithelial part of the ureter and the ureteral orifice was avoided. A pigtail stent was left in situ for 6 weeks. Postoperatively, patients were assessed at 3 months and yearly thereafter. The mean follow-up was 30.5 months.All patients demonstrated symptomatic and radiologic improvement.Endoscopic incision of POM in adults with the holmium laser is safe, simple, and minimally invasive. This procedure should be considered as an initial approach for patients who have failed conservative treatment. However, further follow-up is necessary to determine its long-term efficacy.

To review our initial experience with the holmium laser in patients with recurrent superficial bladder cancer.We treated 41 patients having 71 recurrent superficial transitional-cell tumors of the bladder between December 1994 and September 1997 using the holmium:YAG laser under local anesthesia. The laser treatment was carried out as a part of the follow-up flexible cystoscopy protocol, and topical anesthesia was used. The mean follow-up was 14 months (range 3-33 months).There were 13 recurrent tumors in the treated area and 38 recurrences in the untreated areas. Of interest, a subgroup of 10 patients were treated before 1994 with cystodiathermy and later on with the holmium:YAG laser at various times during their follow-up. The local recurrence rate with cystodiathermy was 32% compared with 10% after laser treatment (P = 0.39). A questionnaire study of 33 patients showed complete satisfaction with the treatment. Only 2 (6%) elected to have a further procedure under general anesthesia. In the series, 83% scored their pain as 2 or less of 10 on a visual analog scale.The absence of complications, high patient satisfaction, and ability to be used in the outpatient setting make the holmium:YAG laser an attractive alternative in the treatment of recurrent superficial cancer of the bladder.

A pilot study of the holmium YAG laser (a solid-state pulsed laser, wavelength 2.1 mum) was performed for tonsillectomy and nasal turbinate surgery. In the nose, intraoperative bleeding was negligible, facilitating an excellent view of the operative field and avoiding the need for postoperative nasal packs. There was no occurrence either of primary or secondary hemorrhage. Some intranasal crusts separated with no difficulty between 3 and 6 weeks. There was no significant delayed tissue destruction. Tonsillectomy was almost bloodless. There was some minor difficulty in mobilizing the upper tonsillar pole. Postoperative pain was no worse than routine tonsillectomy pain and may have been less than would be expected. The tonsil beds healed within two weeks. The comparable roles of the CO 2, the neodymium YAG, and the KTP/532 laser for nasal and oropharyngeal surgery are discussed. These preliminary results suggest a potential role for the holmium YAG laser in nasal turbinate and tonsillar surgery and the need for further evaluation.

We examined the holmium:YAG (Ho:YAG) laser as a tool to perform acute resection of obstructing prostatic tissue in the subgroup of men with benign prostatic hyperplasia (BPH) who present in urinary retention. A total of 36 men presented in acute urinary retention requiring catheterization before undergoing Ho:YAG laser resection of the prostate (HoLRP). Their mean age was 67 years. The mean laser energy delivery was 102 kJ (range 42-315 kJ). The mean postoperative catheterization time was 1.5 days (range 1-8 days), and only 3 men required a catheter for more than 48 hours. There were no acute perioperative complications. Improvement in voiding was immediate and sustained through 6 months of follow-up. At 6 months, the mean peak urinary flow rate was 22.5 mL/sec, and the AUA Symptom Index Score was 5.7. A meatal stricture requiring dilation in one man represents the sole late complication observed in this series. Late recurrence of urinary retention has occurred in two men who had contributing medical problems, for an overall treatment failure rate of 5.6%. Thus, HoLRP represents an effective surgical therapy for patients with bladder outlet obstruction presenting in urinary retention. Morbidity is minimal compared with electrocautery resection, while the efficacy and immediacy of voiding improvement appear similar.

A potential complication of UroLume endoprosthesis is migration, which may necessitate removal of the stent. Stent removal may be associated with complications such as urethral injury, bleeding, and external sphincter trauma. We report a patient in whom a holmium:yttrium–aluminium-garnet (Ho:YAG) laser was used to cut the UroLume endoprosthesis into fragments, which led to easy and uneventful stent removal.