EAU guidelines on laser technologies

Comparison of laser versus cold knife visual internal urethrotomy in the treatment of urethral stricture (stricture length <2 cm): A systematic review and meta-analysis

PURPOSE

There is still controversy regarding the safety and efficacy of cold knife visual internal urethrotomy and laser incisions for the treatment of urethral stricture. This study aims to compare the results of postoperative long-term and short-term maximum urinary flow rates (Qmax), surgical time, postoperative complications, and 1-year recurrence rates between the cold knife and laser surgery.

METHODS

We searched databases including Embase, PubMed, Cochrane, and Clinical Trials.gov to identify relevant literature published in English up to September 2023. We used Stata to compare various parameters. This study is registered in PROSPERO (CRD42023471634). Nine comparative experiments were conducted, involving a total of 659 participants.

RESULTS

The laser group showed significantly better results compared to the cold knife group in terms of postoperative 12-month maximum urinary flow rate (mean differences [MD] 2.131; 95% [1.015, 3.249], P < .0001), postoperative bleeding (RR 0.277, 95% [0.079, 0.977], P = .046), and 1-year recurrence rate (RR 0.667, 95% [0.456, 0.976], P = .037). However, there were no significant differences in postoperative 6-month and 3-month Qmax, surgical time, urethral leakage complications, overall complications, and Visual Analog Scale (VAS) scores.

CONCLUSION

The current study results suggest that laser urethral incision has greater advantages in the long-term (12 months), 1-year recurrence rate, and bleeding complications compared to cold knife urethral incision in the treatment of urethral stricture (<2 cm). Therefore, laser urethral incision may be a better choice for patients with urethral stricture.

Thulium fiber laser enucleation of the prostate: a systematic review of the current outcomes

INTRODUCTION

One recent addition to different lasers used for endoscopic enucleation of the prostate is the thulium fiber laser (TFL). The purpose of this systematic review is to present the feasibility, safety and efficacy of TFL Enucleation of the Prostate (ThuFLEP).

EVIDENCE ACQUISITION

PubMed®, Scopus® and Cochrane® primary databases were systematically screened. The search strategy used the PICO (Patients, Intervention, Comparison, Outcome) criteria. Patients should be adults with benign prostatic obstruction (BPO) undergoing ThuFLEP. While comparative studies reporting comparison of ThuFLEP to other BPO treatments were included, cohort studies with no comparison group were also accepted. Outcomes including enucleation time and complication rates were reported.

EVIDENCE SYNTHESIS

Twelve studies met all the predefined criteria and were included in the final qualitative synthesis. Mean operative time and enucleation time ranged from 46.6±10.2 to 104.5±33.6 and from 38.8±17.9 to 66.0±24.9 minutes, respectively. Most of the complications were Grade I or Grade II ones. Although TFL was found to present some advantages over older BPO treatments, its outcomes were comparable with other endoscopic enucleation approaches.

CONCLUSIONS

ThuFLEP seems to be a feasible, safe and efficient approach for BPO symptoms management. Limited evidence showed that although ThuFLEP was associated with a reduced total operative time, it was also associated with worse IPSS improvement at 1-year follow-up, when compared with MOSESTM Holmium Laser Enucleation of the Prostate (HoLEP). These findings confirm the well-established opinion that the enucleation technique itself is more important than the technology which is used.

The prospective evaluation of learning curve of bipolar anatomic endoscopic prostate enucleation (AEEP) with Herrmann's vapoenucleation probe

PURPOSE

We aimed to evaluate the learning curve of Bipolar Endoscopic Prostate Enucleation (BIPOLEP) in benign prostate enlargement without a mentorship.

METHODS

The prospective data of 55 patients underwent BIPOLEP surgery by a single surgeon during 3 years were evaluated. The demographic, peri-operative and follow-up data were recorded. Trifecta was defined as a combination of complete enucleation and morcellation within < 90 min and without any conversion to standard TURP. Pentafecta was defined as a combination of Trifecta without postoperative complications or stress urinary incontinence at 3 months. The learning curve was considered to have been overcome when the surgeon obtained Trifecta/Pentafecta in four consecutive patients.

RESULTS

The mean age of the study group was 67.9 ± 6.8 years with mean prostate volume of 102.3 ± 56.4 ml. The mean operation time and enucleation time were 103.5 ± 41.1 and 65.78 ± 22.6 min, respectively. Trifecta and Pentafecta were achieved in 23rd (from 19th to 23rd) and 34th (from 30 to 34th) patients, respectively. Among the seven consecutive patients between Trifecta and Pentafecta, prostate capsule perforation was occurred during the surgery in four patients (26th, 27th and 29th patients). The mean follow-up duration was 16.7 ± 6.4 (3-24 months, range) months. Urethral stricture was observed in four (7. 2%) patients while bladder neck contracture was observed 1 (1.8%) patient. After the 3rd month, no patient reported stress incontinence.

CONCLUSION

Bipolar endoscopic enucleation of prostate is a safe surgical method and has similar and/or short learning curve compared to HOLEP even without a mentorship program.

Oncological Outcomes of Thulium-Yttrium-Aluminum-Garnet (Tm:YAG) Laser Ablation for Penile Cancer

OBJECTIVE

To report oncological outcomes after thulium-yttrium-aluminum-garnet (Tm:YAG) laser ablation for penile cancer patients.

MATERIALS AND METHODS

We retrospectively analyzed 71 patients with ≤cT1 penile cancer (2013-2022). All patients underwent Tm:YAG ablation with a RevoLix 200W continuous-wave laser. First, Kaplan-Meier plots and multivariable Cox regression models tested local tumor recurrence rates. Second, Kaplan-Meier plots tested progression-free survival (≥T3 and/or N1-3 and/or M1).

RESULTS

Median (interquartile range) follow-up time was 38 (22-58) months. Overall, 33 (50.5%) patients experienced local tumor recurrence. Specifically, 19 (29%) vs 9 (14%) vs 5 (7.5%) patients had 1 vs 2 vs 3 recurrences over time. In multivariable Cox regression models, a trend for higher recurrence rates was observed for G3 tumors (hazard ratio:6.1; P = .05), relative to G1. During follow-up, 12 (18.5%) vs 4 (6.0%) vs 2 (3.0%) men were retreated with 1 vs 2 vs 3 Tm:YAG laser ablations. Moreover, 11 (17.0%) and 3 (4.5%) patients underwent glansectomy and partial/total penile amputation. Last, 5 (7.5%) patients experienced disease progression. Specifically, TNM stage at the time of disease progression was: (1) pT3N0; (2) pT2N2; (3) pTxN3; (4) pT1N1 and (5) pT3N3, respectively.

CONCLUSION

Tm:YAG laser ablation provides similar oncological results as those observed by other penile-sparing surgery procedures. In consequence, Tm:YAG laser ablation should be considered a valid alternative for treating selected penile cancer patients.

The thermal effect of lasers in urology: a review article

Lasers as a technology have a leading role in the modern urological treatment armamentarium. In this article, the application of lasers in different areas of urology is described. The major uses are in urolithiasis, benign prostatic enlargement (BPE), and management of many urological malignancies and other benign pathologies. Lasers have become an established treatment modality in urolithiasis, an acceptable alternative with the least side effect profile in BPE patients, and a novel and promising therapy in many other fields of Urology.

Evaluation of risk factors, treatment options, and prognostic-related factors in patients with benign ureteral strictures: An 8-year single-center experience

OBJECTIVES

To investigate the etiology, therapeutic effect, and prognosis-related factors of benign ureteral strictures.

METHODS

We analyzed the date of 142 patients with benign ureteral strictures from 2013 to 2021. Ninety-five patients received endourological treatment and 47 patients underwent reconstruction. Preoperative, intraoperative, and postoperative information were compared and analyzed. Symptomatic improvement and radiographic blockage alleviation defined therapeutic success.

RESULTS

Stone-related factors caused 85.2% of cases. The overall success rate of endourological treatment was 51.6% versus 95.7% of reconstruction (p < 0.01). However, endourological treatment was better in terms of postoperative hospital stay time, operation time, and intraoperative blood loss (p < 0.001). In endourological group, patients with stricture length ≤2 cm, mild-to-moderate hydronephrosis, proximal or distal stricture had a higher success rate. Multivariate regression analysis showed that the surgical method was the only independent risk factor affecting success and recurrence. Reconstruction success rate was higher than endourological treatment (p = 0.001, OR 0.057, 95% CI (0.011-0.291)), and recurrence rate was also lower (p = 0.001, HR 0.074, 95% CI (0.016-0.338)). No obvious recurrence was seen in reconstruction, and the median recurrence time in endourological treatment was 51 months.

CONCLUSIONS

Stone-related factors are an important cause of benign ureteral strictures. Reconstruction is the gold standard treatment due to its high success rate and low recurrence rate. Endourological therapy is also preferred as the initial treatment in proximal or distal ureter with length ≤2 cm and mild-to-moderate hydronephrosis. Further close follow-up is required after treatment.

The safe use of lasers in biomedicine: Principles of laser-matter interaction

Optical radiation sources, and in particular lasers, find an ever-increasing number of applications in the medical field. It is essential that personnel who are in the presence of an optical radiation source, whether operator, patient or researcher, know precisely the risks inherent in the exposure of the human body to radiation. In order to reduce the risk of biological damage, beyond the provisions of the law on safety regulations, the precise information and accurate preparation of personnel are the main guarantee for the correct use of these sources. In all the application fields, the possibility of a biological damage cannot be completely eliminated, assuming the connotation of occupational risks. In order to understand the risks and operate their effective mitigation, the basic knowledge of the fundamental concepts at the basis of laser-matter interaction will be presented and discussed, with a focus on the physical parameters needed to efficiently estimate and mitigate the related occupational risks, in both a laboratory and clinical context.

Thulium laser vaporesection of prostates with volume exceeding 100 cm3 as an alternative to HoLEP and ThuLEP

The aim of this study is to evaluate the outcomes of thulium laser vaporesection of prostates with volume exceeding 100 cm³. In the present prospective study, patients with infra-vesical urinary obstruction due to a prostate with volume exceeding 100 cm³ underwent endoscopic vaporesection using thulium laser. In this procedure, prostate chips were resected without morcellation. The technical aspects of surgery, admission time, post-operative catheter time and post-operative complications were analyzed. Flowmetry was performed combined with prostatic ultrasound in the follow-up. Between March 2010 and November 2018, 156 cases with benign prostatic hyperplasia (BPH; volume >100 cm³) were treated. The mean patient age was 67.8 years (48.4-86.6 years), and the mean prostatic volume was 137 cm³ (100-436 cm³). The mean length of hospitalization was 1.48 days (1-8 days), and the mean post-operative catheter time was 5.1 (1-17). Three cases (1.9%) required readmission due to hematuria. The mean follow-up time was 31.2 months (standard deviation = 27.7). Urethral stricture was observed in 14 cases (9%), with bulbar urethra being the most frequent finding. Urinary tract infection was observed in 11 cases (7.1%), and urinary incontinence was observed in 5 cases. The mean peak urinary flow at 12 and 24 months was 26.9 ± 12.5 and 23.9 ± 11.7 ml/s, respectively, and the mean urinary flow during the final follow-up at 41 months was 21.6 ml/s. Thulium laser vaporesection is a valid alternative to open prostatectomy, HoLEP and ThuLEP in patients with large BPH. Urinary flow remained elevated throughout the follow-up.

A Review of How Lasers Are Used in UTUC Surgery: Can the Choice of Laser Affect Outcomes?

Upper tract urothelial carcinoma (UTUC) is a relatively rare disease with an aggressive phenotype compared to urothelial carcinoma in the bladder. In recent years, kidney-sparing surgery (KSS) and, in particular, endoscopic surgery have become the procedure of choice among urologists where the treatment of localized UTUC is concerned. Endoscopy tends to result in satisfactory oncological disease control while lowering morbidity and minimizing complications amongst the appropriately selected cohort of patients. While endoscopic surgery for UTUC might appear to be standardized, it, in fact, differs considerably depending on the source of energy used for resection/ablation. There has been little reliable data up to now on which laser energy source is the most superior. The goal of this review is, therefore, to outline the results of endoscopic UTUC treatment using different lasers and to analyze how these laser-tissue interactions may affect the surgery. We start by pointing out that the data remains insufficient when trying to determine which laser is the most effective in the endoscopic management of UTUC. The ever-growing number of indications for minimally invasive treatment and the increasing number of centers using laser surgery will, hopefully, lead to novel randomized controlled trials that compare the performance characteristics of the lasers as well as the effects of UTUC on patients.

Low- vs. High-Power Laser for Holmium Laser Enucleation of Prostate

Holmium laser enucleation of the prostate (HoLEP) constitutes an established technique for treating patients with symptomatic bladder outlet obstruction. Most surgeons perform surgeries using high-power (HP) settings. Nevertheless, HP laser machines are costly, require high-power sockets, and may be linked with increased postoperative dysuria. Low-power (LP) lasers could overcome these drawbacks without compromising postoperative outcomes. Nevertheless, there is a paucity of data regarding LP laser settings during HoLEP, as most endourologists are hesitant to apply them in their clinical practice. We aimed to provide an up-to-date narrative looking at the impact of LP settings in HoLEP and comparing LP with HP HoLEP. According to current evidence, intra- and post-operative outcomes as well as complication rates are independent of the laser power level. LP HoLEP is feasible, safe, and effective and may improve postoperative irritative and storage symptoms.

Cut-to-the-light technique is useful for complete obstruction of a Wallace ureteroileal anastomosis

Introduction

Obstruction of a ureteroileal anastomosis after urinary diversion is an unpleasant situation for patients and clinicians alike.

Case presentation

A 48-year-old man who underwent a radical cystectomy for muscle-invasive bladder cancer and urinary diversion using the Wallace technique complained of right back pain. Computed tomography showed right hydronephrosis. Cystoscopy via the ileal conduit revealed complete obstruction of the ureteroileal anastomosis. We performed a bilateral approach (antegrade and retrograde) to use the cut-to-the-light technique. A guidewire and 7Fr single J catheter could be inserted.

Conclusion

The cut-to-the-light technique was useful for complete obstruction of the ureteroileal anastomosis, the length of which was <1 cm. Herein, we report on the cut-to-the-light technique with a literature review.

Resistive Switching Crossbar Arrays Based on Layered Materials

Resistive switching (RS) devices are metal/insulator/metal cells that can change their electrical resistance when electrical stimuli are applied between the electrodes, and they can be used to store and compute data. Planar crossbar arrays of RS devices can offer a high integration density (>10⁸  devices mm^{- 2} ) and this can be further enhanced by stacking them three-dimensionally. The advantage of using layered materials (LMs) in RS devices compared to traditional phase-change materials and metal oxides is that their electrical properties can be adjusted with a higher precision. Here, the key figures-of-merit and procedures to implement LM-based RS devices are defined. LM-based RS devices fabricated using methods compatible with industry are identified and discussed. The focus is on small devices (size < 9 µm² ) arranged in crossbar structures, since larger devices may be affected by artifacts, such as grain boundaries and flake junctions. How to enhance device performance, so to accelerate the development of this technology, is also discussed.

Temperature change during laser upper-tract endourological procedures: current evidence and future perspective

PURPOSE OF REVIEW

To examine the most recent data on temperatures produced during laser lithotripsy and to provide several strategies for maintaining lower values and reducing the risk of complications during endourological treatment.

RECENT FINDINGS

Endourologists have access to a wide range of alternatives with the help of the holmium: yttrium-aluminum-garnet (Ho:YAG), thulium: yttrium-aluminum-garnet (TM:YAG), and thulium fiber laser (TFL) that compose a robust and adaptable laser lithotripsy armamentarium. Nevertheless, the threat of thermal damage increases as the local temperature rises with high total power. Most endourologists are not familiar with normal and pathological temperature ranges, how elevated temperatures affect perioperative problems, or how to avoid them.

SUMMARY

Increased temperatures experienced during laser lithotripsy may affect the course of the healing process. All lasers display a safe temperature profile at energies below 40 W. At equal power settings, Ho:YAG, Tm:YAG, and TFL lasers change the temperature comparably. Shorter on/off laser activation intervals, chilled irrigation, open irrigation systems, and UASs all aid in maintaining acceptable temperatures.

Tissue thermal effect during lithotripsy and tissue ablation in endourology: a systematic review of experimental studies comparing Holmium and Thulium lasers

PURPOSE

We looked into the Thulium: yttrium-aluminum-garnet (TM:YAG), Thulium Fibre laser (TFL) and Holmium: yttrium-aluminum-garnet (Ho:YAG) thermal laser tissue effect during lithotripsy and tissue ablation.

METHODS

We performed a PubMed, Scopus, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) search.

RESULTS

During lithotripsy, the Ho:YAG generated temperatures from 24 to 68.7 °C at powers < 20 W, the Tm:YAG from 43.7 °C at 30 W to 68 °C at powers < 20 W, and the TFL from 33 to 40.46 °C. During ablation, the Ho:YAG and continuous wave (cw) Tm:YAG tissue incision depths ranged from 0.08 to 2.26 mm, and from 0.28 to 3.22 mm. The Ho:YAG and Tm:YAG vaporization areas ranged from 0.044 to 0.078 mm² and from 0.050 to 0.078 mm³ and their coagulation zones were 0.075 mm² and 0.125 mm³ respectively. Ho:YAG and Tm:YAG laser damage zones ranged from 0.093 to 2.6 mm³ and from 0.207 to 0.98 mm³ respectively. The TFL incision depth ranged from 0.04 to 5.7 mm. The cw and SuperPulsed (SP) vaporization volumes ranged from 8 to 28.2 mm³/s and from 4 to 11 mm³/s. TFL coagulation depth and coagulation zone ranged from zero to 1.1 mm, 2.2 to 5.1 mm³ in SP mode and from 7.7 to 18.1 mm³ in cw mode.

CONCLUSION

During lithotripsy all lasers caused similar temperature changes and had a safe temperature profile at < 40 W. During tissue ablation, Ho:YAG has a deeper incision depth, while cwTm:YAG and cwTFL have broader coagulation and total laser areas.

Effectiveness and Safety of Thulium Fiber Laser in the Conservative Management of Patients with Upper Tract Urothelial Carcinoma

Background

Few clinical data are available on thulium fiber laser (TFL) and conservative treatment of upper urinary tract urothelial carcinoma (UTUC).

Objective

To assess the effectiveness and safety of TFL in the conservative treatment of UTUC in terms of both tumor ablation and complication rates in a short-term follow-up.

Design setting and participants

Retrospective data were collected from all patients who underwent endoscopic management of UTUC between January 2021 and April 2022. All patients with nonmetastatic UTUC who were deemed suitable candidates (low- and high-grade disease) for conservative treatment were reviewed.

Intervention

All patients underwent ureteroscopy with biopsy and at 2, 6, and 12 mo after the first surgery. UTUC ablation was achieved using TFL.

Outcome measurements and statistical analysis

Clinical data were collected in a dedicated database. Intra- and postoperative outcomes were assessed. A descriptive statistical analysis was performed.

Results and limitations

In total, 28 patients were evaluated. Thirteen patients (46.4%) were included in the low-risk UTUC treatment group and 15 (53.6%) in the high-risk group. The mean tumor size was 15.3 ± 5.7 mm. Biopsy showed low- and high-grade UTUCs in 19 and eight patients, respectively. Only one biopsy was inconclusive for achieving a diagnosis. At the second procedure biopsy, no tumor was found in 19 cases (70.4%), whereas seven had tumors confirmed (25.9%). To date, 23 and 17 out of 26 patients completed the 6- and 12-mo follow-up, respectively. UTUC recurrence was detected in five of 23 patients (21.7%) and in three of 17 patients (17.7%) at 6 and 12 mo, respectively. A total of 95 procedures were performed. No intraoperative complications were observed. In ten of the 95 procedures (10.5%), Clavien-Dindo grade I-II postoperative complications were experienced. Only one grade IIIB postoperative complication was noted.

Conclusions

TFL is a safe and effective technique for conservative treatment of UTUC in a short-term follow-up. Optimal tumor ablation and fine hemostatic control were achieved without major complications.

Patient summary

In this study, we looked at the outcomes of upper urinary tract tumors conservatively treated with the new thulium fiber laser (TFL). We conclude that TFL represents a safe and effective technique for the treatment of this kind of tumors in a short-term follow-up.

Thulium Fiber Laser Behavior on Tissue During Upper- and Lower-Tract Endourology

PURPOSE OF REVIEW

To present the latest evidence on thulium fiber laser (TFL) effects on tissue, during lithotripsy and ablation, emphasizing on generated temperatures, thermal damage thresholds, incision depths, areas of coagulation, and laser damage.

RECENT FINDINGS

Lasers are frequently utilized during endoscopic treatment of different urological conditions. The holmium:yttrium-aluminum-garnet (Ho:YAG) is most frequently used for various types of stones and soft tissue. The TFL has been recently introduced, offering several advantages. However, its activity on tissue during upper and lower tract endourology is poorly understood. At equivalent power settings, TFL and Ho:YAG generate similar temperature changes during lithotripsy. TFL has a shallow incision depth during tissue ablation. Compared to SP TFL, (cw) TFL results in a broader coagulation zone, whereas SP TFL gives of Ho:YAG-similar incision, and (cw) TFL offers a quick, precise cut with more carbonization.

A novel integrated angioscope-laser system for atherosclerotic carotid artery occlusion: Feasibility and techniques

Introduction

Atherosclerotic extracranial carotid artery stenosis accounts for about 20%-30% of all strokes, which is one of the leading causes of adult morbidity and mortality. Although carotid endarterectomy (CEA) is still the mainly operational manner for atherosclerotic carotid artery stenosis/occlusion (ACAS/ACAO), and carotid angioplasty and stenting (CAS) have been used as an alternative, both CEA and CAS have limitations of their own, such as extensive invasiveness and in-stent restenosis.

Methods

In this study we established a novel interventional system in vitro to take advantage of both CEA and CAS. Twenty consecutive carotid atherosclerotic plaques were harvested from the patients who underwent CEA. The plaques were randomized into two groups and inserted into the pruned and sutured descending aortas of the swine in vitro. The ZebraScope™ was modified with a protective device on its flexible tip, so that the plaque could be dissected from the wall of parent carotid artery and ablated completely without damage to the carotid artery. The holmium:YAG (Ho:YAG) and thulium fiber laser (TFL) generators were alternately used when needed.

Results

All the carotid atherosclerotic plaques were completely ablated by Ho:YAG laser and/or TFL. The Ho:YAG laser was more effective for the atherosclerotic plaques with severe calcification, while the TFL was more suitable for those with moderate calcification. There were still some thermal injury spots on the inner wall of the parent carotid artery caused by the laser in the non-protected group B. In the protected group A, on the contrary, there was no even a thermal injury spot was found on the relevant location except for one sample. The difference of ablating duration was statistically significant between group A (36.5 ± 4.79 min) and group B (63.4 ± 6.55 min) (P < 0.01).

Conclusion

According to our knowledge, this is the first attempt to ablate carotid atherosclerotic plaques assisted by the ZebraScope™ in vitro. The protective and dissecting device on the tip of the angioscope makes it safe and visible when the ablation is performed to carotid atherosclerotic plaques. The Ho:YAG laser and TFL are effective and safe for ablating the plaque in vitro.

Holmium: yttrium-aluminum-garnet laser with Moses: does it make a difference?

PURPOSE OF REVIEW

Moses effect is an inherent physical principle of Ho:YAG laser functioning. Moses Technology is a pulse modulation modality of Ho:YAG laser, which became commercially available for the treatment of two urological conditions: urinary stones and benign prostatic obstruction. The purpose of this narrative review is to distinguish between Moses effect and Moses Technology, as well as to summarize the latest evidence on Moses Technology and its main application in the urological field.

RECENT FINDINGS

During laboratory lithotripsy, Moses Technology seems to reduce stone retropulsion and determine higher ablation volume compared with regular lithotripsy. However, this technology presents similar characteristics to long pulse Ho:YAG laser, and several studies showed no significant difference between Moses Technology and standard lasers. When used in prostate enucleation, Moses Technology promises to reduce operating time by increasing the efficiency of prostate resection and improve the hemostasis. Moreover, some studies state that it is possible to reduce the HoLEP morbidity. Despite this, the clinical impact of the time reduction remains uncertain and different studies either present relevant limitations or are burdened by significant bias.

SUMMARY

Although Moses effect has been extensively described and characterized, and several studies have been published on the usage of Moses Technology for both laser lithotripsy and laser enucleation of the prostate with Holmium YAG, solid clinical evidence on the real improvement of surgical outcomes is still missing.

Comprehensive endoscopic management of impacted ureteral stones: Literature review and expert opinions

Treatment of urolithiasis, a benign disease, requires high efficacy and safety. Endoscopic treatment of impacted ureteral stones remains a challenging procedure for urologists, despite recent remarkable advances in surgical technology in treatment of urolithiasis. The success rate of endoscopic treatment in patients with impacted stones is reported to be lower than that in patients with nonimpacted stones. Moreover, the presence of stone impaction is associated with high rates of intraoperative and postoperative complications. The best management for patients with impacted ureteral stones should therefore be devised based on the latest knowledge and techniques. The present review focuses on the preoperative prediction of stone impaction, the safest and most effective endoscopic surgical procedures, and the most appropriate management for postoperative ureteral strictures. We overview comprehensive endoscopic management for impacted ureteral stones based on literature review and expert opinions.

Laser technology in urologic oncology

Laser technology has been used in Urology since the 80s with a lot of different applications in endoscopic and open surgery. With the developments of the technology and the introduction of new active medium and source of laser energy, this technology have become the gold standard not only in stone surgery but even in benign prostate enlargement (BPE) surgical treatment. Regarding urologic oncology, laser energy has now reached an important role in focal therapy and in conservative treatment. The possibility of having better functional outcomes without any relevant impact on oncological results led to an increased use of laser in penile surgery, with a significant mention in urological guidelines for this option. In urothelial cancers as well, both in conservative management of upper tract tumors that in the treatment of non muscle invasive bladder cancer, a clear role of these relatively new source of energy have been demonstrated. Finally, both in prostate that in renal cancer the strategy of focal therapy may take advantage from this precise and fine technology. In this review we analyzed and described the applications of laser energy in urological cancers with a specific focus on penile, urothelial and prostate cancer.

Generated temperatures and thermal laser damage during upper tract endourological procedures using the holmium: yttrium-aluminum-garnet (Ho:YAG) laser: a systematic review of experimental studies

PURPOSE

To perform a review on the latest evidence related to generated temperatures during Ho:YAG laser use, and present different tools to maintain decreased values, and minimize complication rates during endourological procedures.

METHODS

We performed a literature search using PubMed, Scopus, EMBASE, and Cochrane Central Register of Controlled Trials-CENTRAL, restricted to original English-written articles, including animal, artificial model, and human studies. Different keywords were URS, RIRS, ureteroscopy, percutaneous, PCNL, and laser.

RESULTS

Thermal dose (t43) is an acceptable tool to assess possible thermal damage using the generated temperature and the time of laser exposure. A t43 value of more than 120 min leads to a high risk of thermal tissue injury and at temperatures higher than 43 °C Ho:YAG laser use becomes hazardous due to an exponentially increased cytotoxic effect. Using open continuous flow, or chilled irrigation, temperatures remain lower than 45 °C. By utilizing high-power (> 40 W) or shorter laser pulse, temperatures rise above the accepted threshold, but adding a ureteral access sheath (UAS) helps to maintain acceptable values.

CONCLUSIONS

Open irrigation systems, chilled irrigation, UASs, laser power < 40 W, and shorter on/off laser activation intervals help to keep intrarenal temperatures at accepted values during URS and PCNL.

The Efficacy and Safety of Transurethral 2 μm Laser Bladder Lesion Mucosal En Bloc Resection in the Treatment of Cystitis Glandularis

Objective

To study the safety and feasibility of transurethral bladder lesion mucosal en bloc resection with 2 μm laser for cystitis glandularis.

Methods

From July 2018 to July 2019, 58 patients with cystitis glandularis received surgical treatment were selected. All patients in this study were randomly divided into experimental group (transurethral 2 μm laser bladder lesion mucosal en bloc resection) and control group (traditional transurethral resection of bladder lesion mucosal). By analyzing the perioperative and follow-up clinical data of these two operation procedures, we discuss the efficacy and safety of transurethral 2 μm laser bladder lesion mucosal en bloc resection in the treatment of cystitis glandularis.

Results

Patients of two groups received operation successfully without serious complications such as bladder perforation. Compared with the experimental group, the laser treated group hadless bleeding in operation, shorter post-operative catheter indwelling time. These differences were statistically significant. No significant difference existed between two groups in terms of operative time, Bladder flushing time, irritation symptoms of bladder.

Conclusion

Transurethral 2 μm laser bladder lesion mucosal en bloc resection is safe and effective for the treatment of cystitis glandularis, and it is worthy of further clinical application.

En bloc resection for nonmuscle-invasive bladder cancer: selecting a proper laser

PURPOSE OF REVIEW

To discuss the most recent surgical lasers that have been made available to us and to evaluate their potential in performing en bloc resection of nonmuscle invasive bladder cancer.

RECENT FINDINGS

Laser en bloc resection of bladder tumors (ERBT) can be performed with a number of laser systems including Ho:YAG, GreenLight, diode, Tm:YAG and thulium fiber lasers (TFL). The data that is currently available suggests that the water-targeting devices (utilizing water as a primary chromophore - Ho:YAG, Tm:YAG, TFL) may have a number of advantages over hemoglobin-targeting systems (potassium titanyl phosphate:YAG, lithium triborate:YAG). One recent addition to the surgical armamentarium Moses effect enhanced Ho:YAG and the TFL (being able to work both in quasi-continuous and SuperPulsed modes) necessitates careful discussion and comparison with the other available devices.

SUMMARY

The majority of available lasers have proven to be safe to use and compared to electrocautery allow for lower rates of obturator nerve reflex and result in fewer bleeding complications. The minimal penetration depth and decreased peak power of Tm:YAG and TFLs render them the devices of choice when it comes to ERBT. Unfortunately, more studies on ERBT with TFL are needed in order for us to make a sound assessment of the respective pros and cons.

Comparison of various types of lasers and transurethral resection in the treatment of bladder tumors: a systematic review and meta-analysis

Bladder cancer is one of the most common cancers of the urinary tract. The two available treatments for this malignancy are laser and Transurethral Resection of the Bladder Tumor (TURBT). The aim of this study was to compare the different parameters of these two methods. A systematic search was performed on PubMed, Scopus and Google Scholar between 2000 and 2021. All articles related to non-muscle invasive bladder cancer (NMIBC) were extracted. All analyses were performed using R-studio statistical software version 1.0.136. In total, 11 studies that reported tumor recurrence in two methods were evaluated. A total of 626 and 742 patients were treated with laser and TURBT, respectively. Tumor recurrence, duration of operation, hospitalization and catheterization in laser therapy were significantly lower than TURBT. In addition, the incidence of complications was lower in patients treated with laser. The incidence of obturator nerve reflex, bladder perforation and postoperative bladder irrigation was significantly higher in patients treated with TURBT. Only in relation to postoperative urethral stricture, no significant difference was observed between the two treatment methods. Laser therapy compared to TURBT in patients with NMIBC has fewer complications and faster recovery. Also, the risk of tumor recurrence in laser therapy is less than TURBT.

Ex-Vivo Exposure on Biological Tissues in the 2-μm Spectral Range with an All-Fiber Continuous-Wave Holmium Laser

We present the results on the interaction of an all-fiber Holmium-doped laser CW radiation at a wavelength of 2100 nm with soft tissues and compare it with the other results obtained by the most used solid-state laser systems. Ex-vivo single spot experiments were carried out on the porcine longissimus muscles by varying the laser impact parameters in a wide range (average output power 0.3, 0.5 and 1.1 W; exposure time 5, 30 and 60 s). Evaluation of the laser radiation exposure was carried out by the size of coagulation and ablation zones on the morphological study. Exposure to a power of 0.3 W (1.5–18 J of applied energy) caused only reversible changes in the tissues. The highest applied energy of 66 J for 1.1 W and a 60-s exposure resulted in a maximum ablation depth of approximately 1.2 mm, with an ablation efficiency of 35%. We have shown that it is not necessary to use high powers of CW radiation, such as 5–10 W in the solid-state systems to provide the destructive effects. Similar results can be achieved at lower powers using the simple all-fiber Holmium laser based on the standard single-mode fiber, which could provide higher power densities and be more convenient to manufacture and use. The obtained results may be valuable as an additional experimental point in the field of existing results, which in the future will allow one to create a simple optimal laser system for medical purposes.

Holmium: YAG Versus Cold Knife Internal Urethrotomy in the Management of Short Urethral Strictures: A Randomized Controlled Trial

Introduction: our study aimed to assess the safety and efficacy of Holmium: YAG laser internal urethrotomy compared to the cold knife internal urethrotomy. Methods: Eighty adult male patients presented with a urethral stricture less than 1.5 cm were included in our study; they were randomly allocated into 2 groups representing Holmium and cold knife internal urethrotomy. A careful evaluation with ascending cystourethrogram and uroflowmetry were done on all patients, and they were followed up for 1 year with uroflowmetry. Results: Each group included 40 patients sharing the same demographic data. The most common cause of a urethral stricture in both groups was iatrogenic injury. The mean operative time of the cold knife urethrotomy procedure was 10.98 ± 2.40 minutes compared to 15.43 ± 2.48 minutes in the holmium laser urethrotomy group with a highly significant difference. The results showed success rates of 90% and 80% for the holmium laser and cold knife internal urethrotomy groups respectively. The perioperative complication according to the Clavien-Dindo classification, showed no statistically significant difference in grade 1 and 2 complications. A recurrence rate with the need for redo surgery representing grade 3B complication was seen in 4 cases in the Holmium group compared to 8 cases in the cold knife group with a statistically significant difference. Conclusion: Both Holmium Laser and cold knife internal urethrotomy are an effective surgical option for the treatment of a urethral stricture less than 1.5 cm with a promising outcome after 1-year follow-up with a better success rate using the Holmium laser.

Determination of Face and Content Validity of Cadaveric Model for Holmium Anatomic Endoscopic Enucleation of the Prostate Training: An ESUT AEEP Group Study

Background

Bench and virtual reality nonbiological simulator models for anatomic endoscopic enucleation of the prostate (AEEP) surgery have been reported in the literature. These models are acceptable but have limited practical applications.

Objective

To validate a fresh-frozen human cadaver model for holmium AEEP training and assess its content validity.

Design, setting, and participants

Holmium AEEP operations on fresh-frozen cadavers performed by an experienced surgeon were recorded, and a video, including the main steps of the operation, was produced.

Outcome measurements and statistical analysis

The video and an accompanying questionnaire were subsequently distributed electronically to ESUT AEEP study group experts and associates (N = 32) for assessment of the AEEP training model. A ten-point Likert global rating scale was used to measure the content validity.

Results and limitations

A total of 26 answers were returned (81%). The experts agreed on the model’s suitability for AEEP training (mean Likert score: 8). According to the responses, “identifying anatomic structures and landmarks” was the most valuable aspect of the model in terms of AEEP training (median Likert score: 9). Conversely, the experts found the model’s ability, in terms of demonstrating laser and tissue reactions, to be weak (median Likert score: 6)

Conclusions

Based on the content validity assessment, the fresh-frozen cadaver-training model for laser AEEP seems to be a promising model for demonstrating and learning the correct prostate enucleation technique.

Patient summary

An increasing number of researchers have proposed that anatomic endoscopic enucleation of the prostate (AEEP) should replace transurethral resection of the prostate surgery and become the gold standard for treatment of bladder outlet obstruction due to benign prostatic hyperplasia. AEEP requires anatomic familiarity for enucleation, technical knowledge, and a solid training program before starting with the first cases. This is the first cadaver study to assess the content validity of a fresh-frozen human cadaver model for AEEP training.

Risk Factors of Emergency Room Visits for Bleeding Complications Following Transurethral Procedures in the Treatment of Benign Prostatic Hyperplasia: A Retrospective Cohort Study

Purpose

Transurethral procedures, including transurethral resection of the prostate (TURP) and laser prostatectomy, are often linked to emergency room (ER) visits for postoperative bleeding. Although some studies have been conducted, the risk factors associated with these ER visits are not completely understood. This retrospective cohort study identified potential risk factors associated with ER visits for postoperative bleeding.

Patients and Methods

Preoperative assessment data and operational and postoperational parameters recorded at Chang Gung Memorial Hospital, Taiwan between December 2015 and January 2017 for patients who underwent elective transurethral procedures were analyzed to identify potential risk factors. The primary endpoint was ER visits for gross hematuria within three months following operation, and the secondary endpoint was ER visits for blood clot-induced urinary retention (clot retention) within three months following operation.

Results

A total of 665 patients who underwent elective transurethral procedures were enrolled. The transurethral procedures included monopolar transurethral resection of the prostate (M-TURP), bipolar TURP (B-TURP), greenlight photoselective vaporization of the prostate (PVP), thulium laser enucleation of the prostate (ThuLEP) and thulium laser transurethral vaporesection of the prostate (ThuVARP). Regarding ER visits for clot retention within three months, multivariable logistic regression revealed significantly lower rates of clot retention in patients who received B-TURP than in those who underwent ThuVARP (AOR, 0.18; 95% confidence interval [CI], 0.04–0.82, p = 0.027). Moreover, significantly higher clot retention was observed in patients who underwent two or more rounds of manual irrigation (AOR, 9.51; 95% CI, 1.66–54.43, p = 0.011).

Conclusion

Multiple manual irrigations shortly after operation can be considered a novel predictor of postoperative clot retention-related ER visits. Among the transurethral procedures, ThuVARP was associated with a higher risk of clot retention-related ER visits than was B-TURP.

A systematic review of experimental and clinical studies reporting on in situ laser fenestration of aortic endografts

OBJECTIVE

To summarize available in-situ laser fenestration (ISLF) literature, including experimental studies with their subsequent recommendations regarding optimal fenestration technique and fabric; as well as the short and mid-term results of clinical studies.

METHODS

A systematic review of English articles was performed in MEDLINE, the Cochrane Database and EMBASE, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines by two researchers. The search period was without starting date until the 31^st August 2020, and search terms included were in situ, laser, fenestration, and endograft. Quality assessment of the studies was performed using the Newcastle-Ottawa scale by two other independent researchers.

RESULTS

A total of 19 clinical studies were included, with a total of 428 patients (390 supra-aortic trunk ISLF, 38 visceral vessel ISLF). The technical success was 96.9% and 95.6% supra-aortic and visceral vessel ISLF, respectively. Most studies have less than 12-month follow-up, and the longest available follow-up (in one study) was 5-years for left-subclavian fenestration and 17-months for visceral vessel ISLF. Overall, the quality of the evaluated clinical studies was low. Six experimental studies were included, with the highest level of evidence suggesting fenestration of multifilament polyethylene terephthalate grafts, followed by dilation with either a 6- or 8-mm non-compliant balloon.

CONCLUSION

Experimental studies favour the use of multifilament polyethylene terephthalate , followed by dilation with non-compliant balloons as the most durable "in-vitro" technique for ISLF. Short-term outcomes for arch and visceral vessel revascularization are promising, with low rates of in-hospital mortality, stroke, and end-organ ischemia. Nonetheless, the long-term durability of ISLF is yet to be determined and they should be limited to selected symptomatic or urgent cases.

A Systematic Review of Thulium Fiber Laser: Applications and Advantages of Laser Technology in the Field of Urology

Laser technology is widely used in urological surgery, from lithotripsy, prostate surgery to en-bloc resection of tumours. While Holmium:YAG has been widely employed over the last two decades, in recent years, there has been a surge of interest in Thulium Fiber Laser (TFL), which offers theoretical advantages of better water absorption and lower stone ablation thresholds. A systematic review was conducted to assess the evidence from clinical research on TFL's application for lithotripsy and prostate surgery. It identified 357 articles and 8 (1506 patients) were selected, of which 4 clinical studies each investigated TFL enucleation of prostate (ThuFLEP) and TFL lithotripsy. For flexible ureteroscopic lithotripsy (FURSL), stone ablation settings ranged from 0.1-4 J, and 7-300 Hz, mean operative time ranged from 23.4-39.8 minutes and lasing time ranged from 1.2-10 minutes. For stone dusting in percutaneous nephrolithotomy (PCNL), settings of 0.2 J and 125-200 Hz were found to be optimal. For ThuFLEP, all studies showed a significant improvement in IPSS (International Prostate Symptom Score), urinary flow rate (Qmax), quality of life measures, and post-void residual volume, with mean operative time ranging from 67-104.5 minutes. Our review shows that there is limited evidence on the use and clinical outcomes of TFL. ThuFLEP might suggest equivalence to the widely used HoLEP in the available evidence so far. TFL lithotripsy shows promising results but further prospective, randomized trials are required to properly assess its usability, clinical effectiveness and standardisation of the settings for successful adoption of the technology.

Comparison of Holmium:YAG and Thulium Fiber Lasers on the Risk of Laser Fiber Fracture

Objectives: To compare the risk of laser fiber fracture between Ho:YAG laser and Thulium Fiber Laser (TFL) with different laser fiber diameters, laser settings, and fiber bending radii. METHODS: Lengths of 200, 272, and 365 μm single use fibers were used with a 30 W Ho:YAG laser and a 50 W Super Pulsed TFL. Laser fibers of 150 µm length were also tested with the TFL only. Five different increasingly smaller bend radii were tested: 1, 0.9, 0.75, 0.6, and 0.45 cm. A total of 13 different laser settings were tested for the Ho:YAG laser: six fragmentation settings with a short pulse duration, and seven dusting settings with a long pulse duration. A total of 33 different laser settings were tested for the TFL. Three laser settings were common two both lasers: 0.5 J × 12 Hz, 0.8 J × 8 Hz, 2 J × 3 Hz. The laser was activated for 5 min or until fiber fracture. Each measurement was performed ten times. Results: While fiber failures occurred with all fiber diameters with Ho:YAG laser, none were reported with TFL. Identified risk factors of fiber fracture with the Ho:YAG laser were short pulse and high energy for the 365 µm fibers (p = 0.041), but not for the 200 and 272 µm fibers (p = 1 and p = 0.43, respectively). High frequency was not a risk factor of fiber fracture. Fiber diameter also seemed to be a risk factor of fracture. The 200 µm fibers broke more frequently than the 272 and 365 µm ones (p = 0.039). There was a trend for a higher number of fractures with the 365 µm fibers compared to the 272 µm ones, these occurring at a larger bend radius, but this difference was not significant. Conclusion: TFL appears to be a safer laser regarding the risk of fiber fracture than Ho:YAG when used with fibers in a deflected position.

A Modified Technique of Thulium Laser Enucleation for Benign Prostatic Hyperplasia With Non-morcellator Approach

Background: Until recently, most enucleation techniques of the prostate were performed with the application of morcellator. We introduce a modified enucleation technique of thulium laser with non-morcellator approach, which is about incising and vaporizing remaining prostate tissue instead of a morcellator.

Methods: A retrospective evaluation of 223 patients undergoing ThuLEP from January 2014 to December 2015 was performed in our institution. One hundred five of the patients used morcellator while the other 118 used non-morcellator approach. All patients were assessed with the International Prostate Symptom Score (IPSS), quality of life (Qol), ultrasonography, serum prostate-specific antigen (PSA), maximal urine flow rate (Qmax), and postvoid residual urine volume (PVR). We reassessed these parameters at 1-, 3-, 6-, and 12-months after operation. Operative time, perioperative, and postoperative complications were also recorded.

Results: Significant improvement was noted in the IPSS, QoL, Qmax, and PVR in both groups at the 12-month follow-up, and assessment showed no differences in these parameters between the two groups. Comparisons of the total operation time and enucleation time demonstrated no significant differences between the two groups. Our non-morcellator approach needed more time to incise and vaporize the enucleated tissue compared to morcellation when the prostate volume was about 40–80 ml (p < 0.05), while it showed a significant lower rate of superficial bladder injury than using morcellator (p < 0.05). There were no significant differences in other complications between the two groups (p > 0.05).

Conclusions: Our modified technique is a safe and effective procedure for the treatment of BPH avoiding the potential complications caused by morcellator.

A review of thulium-fiber laser in stone lithotripsy and soft tissue surgery

PURPOSE OF REVIEW

To evaluate emerging evidence and practical applications of thulium-fiber laser (TFL) for genitourinary soft tissue disease and urinary stone disease treatment.

RECENT FINDINGS

A systematic review was developed using the PubMed, ScienceDirect, Wiley, SpringerLink and Mary Ann Liebert Scopus databases between 2012 and 2020 years, using the PRISMA statement. We analyzed recent publications including in vitro and in humans outcomes of surgery using TFL. This new laser technology can be used in soft tissue diseases and stones present in the genitourinary system. Most of the comparisons are made with the Ho:YAG laser, using completely different settings. Nevertheless, TFL is safe, feasible and effective in the management of urologic diseases, showing superiority to Ho:YAG even in some studies.

SUMMARY

The introduction of pulsed TFL technology has enabled the ablation of stones at rates comparable to or better than currently existing lasers in vitro, while also potentially reducing stone retropulsion. TFL is effective in treating genitourinary soft tissue diseases, including benign prostatic hyperplasia, and early data indicate that it may be effective in the treatment of urinary stone disease. More clinical studies are needed to better understand the indications for this novel technology and clarify its position in the urologic endoscopy armamentarium.

Thulium fiber laser utilization in urological surgery: A narrative review

The thulium fiber laser (TFL) is a novel technology under active investigation as an conceivable alternative to the Holmium:yttrium-aluminum-garnet (Ho:YAG) laser, which is currently the gold standard for an array of urologic procedures. The purpose of this review is to discuss the existing literature on the functionality and effectiveness of TFL in urological practice. We conducted a search of the PubMed, Medline, Web of Science Core Collection, SCOPUS, Embase (OVID), and Cochrane Databases for all full articles and systematic reviews on the TFL. We found a total of 35 relevant pieces of literature. The early research findings pertaining to the TFL exhibit numerous potential advantages over the Ho:YAG laser. In vitro and ex vivo studies have highlighted the TFL's ability to utilize smaller laser fibers, obtain faster stone ablation rates, and achieve less retropulsion when tested against the Ho:YAG laser in lithotripsy. Currently, there is limited in vivo research that investigates the utilization of the TFL. The in vivo results that are available, however, look promising both for laser lithotripsy and soft tissue ablation. Indeed, the existing literature suggests that the TFL has great potential and may possess numerous technological advantages over the Ho:YAG laser, especially in laser lithotripsy. Although these early studies are promising, randomized control trials are needed to assess the full applicability of the TFL in urology.

Robotic Ureteral Reconstruction in Patients with Radiation-Induced Ureteral Strictures: Experience from the Collaborative of Reconstructive Robotic Ureteral Surgery

Objectives: Management of radiation-induced ureteral stricture (RIUS) is complex, requiring chronic drainage or morbid definitive open reconstruction. Herein, we report our multi-institutional comprehensive experience with robotic ureteral reconstruction (RUR) in patients with RIUSs. Patients and Methods: In a retrospective review of our multi-institutional RUR database between January 2013 and January 2020, we identified patients with RIUSs. Five major reconstruction techniques were utilized: end-to-end (anastomosing the bladder to the transected ureter) and side-to-side (anastomosing the bladder to an anterior ureterotomy proximal to the stricture without ureteral transection) ureteral reimplantation, buccal or appendiceal mucosa graft ureteroplasty, appendiceal bypass graft, and ileal ureter interposition. When necessary, adjunctive procedures were performed for mobility (i.e., psoas hitch) and improved vascularity (i.e., omental wrap). Outcomes of surgery were determined by the absence of flank pain (clinical success) and absence of obstruction on imaging (radiological success). Results: A total of 32 patients with 35 ureteral units underwent RUR with a median stricture length of 2.5 cm (interquartile range [IQR] 2-5.5). End-to-end and side-to-side reimplantation techniques were performed in 21 (60.0%) and 8 (22.9%) RUR cases, respectively, while 4 (11.4%) underwent an appendiceal procedure. One patient (2.9%) required buccal mucosa graft ureteroplasty, while another needed an ileal ureter interposition. The median operative time was 215 minutes (IQR 177-281), estimated blood loss was 100 mL (IQR 50-150), and length of stay was 2 days (IQR 1-3). One patient required repair of a small bowel leak. Another patient died from a major cardiac event and was excluded from follow-up calculations. At a median follow-up of 13 months (IQR 9-22), 30 ureteral units (88.2%) were clinically and radiologically effective. Conclusion: RUR can be performed in patients with RIUSs with excellent outcomes. Surgeons must be prepared to perform adjunctive procedures for mobility and improved vascularity due to poor tissue quality. Repeat procedures for RIUSs heighten the risk of necrosis and failure.

Thulium:YAG Versus Holmium:YAG Laser Effect on Upper Urinary Tract Soft Tissue: Evidence from an Ex Vivo Experimental Study

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 these two lasers at various settings, with a focus on incision depth (ID) and coagulation area (CA). Materials and Methods: An ex vivo experimental study was performed in a porcine model. The kidneys were dissected to expose the upper urinary tract and the block samples containing urothelium and renal parenchyma were prepared. The laser fiber, fixed on a robotic arm, perpendicular to the target tissue was used with a 100 W Ho:YAG and a 200 W Tm:YAG. Incisions were made with the laser tip in contact with the urothelium and in continuous movement at a constant speed of 2 mm/s over a length of 1.5 cm. Total energy varied from 5 to 30 W. Incision shape was classified as follows: saccular, triangular, tubular, and irregular. ID, vaporization area (VA), CA, and total laser area (TLA = VA + CA) were evaluated. Statistical analysis was performed using the SPSS V23 package, p-values <0.05 were considered statistically significant. Results: A total of 216 experiments were performed. Incision shapes were saccular (46%), triangular (38%), and irregular (16%) with the Ho:YAG, while they were tubular (89%) and irregular (11%) with the Tm:YAG. ID was significantly deeper with the Ho:YAG (p = 0.024), while CA and TLA were larger with the Tm:YAG (p < 0.001 and p < 0.005). Conclusion: ID was deeper with Ho:YAG, whereas CA and TLA were larger with the Tm:YAG. Considering surgical principles for endoscopic ablation of upper tract urothelial carcinoma, these results suggest that Tm:YAG may have a lower risk profile (less depth of incision) while also being more efficient at tissue destruction. Future in vivo studies are necessary to corroborate these findings.

Thulium laser transurethral vaporesection versus transurethral resection of the prostate for benign prostatic obstruction: the UNBLOCS RCT

BACKGROUND

Transurethral resection of the prostate (TURP) is the standard operation for benign prostatic obstruction (BPO). Thulium laser transurethral vaporesection of the prostate (ThuVARP) vaporises and resects the prostate using a technique similar to TURP. The small amount of existing literature suggests that there may be potential advantages of ThuVARP over TURP.

OBJECTIVE

To determine whether or not the outcomes from ThuVARP are equivalent to the outcomes from TURP in men with BPO treated in the NHS.

DESIGN

A multicentre, pragmatic, randomised controlled parallel-group trial, with an embedded qualitative study and economic evaluation.

SETTING

Seven UK centres - four university teaching hospitals and three district general hospitals.

PARTICIPANTS

Men aged ≥ 18 years who were suitable to undergo TURP, presenting with bothersome lower urinary tract symptoms (LUTS) or urinary retention secondary to BPO.

INTERVENTIONS

Patients were randomised 1 : 1 to receive TURP or ThuVARP and remained blinded.

MAIN OUTCOME MEASURES

Two co-primary outcomes - patient-reported International Prostate Symptom Score (IPSS) and clinical measure of maximum urine flow rate (Qmax) at 12 months post surgery.

RESULTS

In total, 410 men were randomised, 205 to each arm. The two procedures were equivalent in terms of IPSS [adjusted mean difference 0.28 points higher for ThuVARP (favouring TURP), 95% confidence interval (CI) -0.92 to 1.49 points]. The two procedures were not equivalent in terms of Qmax (adjusted mean difference 3.12 ml/second in favour of TURP, 95% CI 0.45 to 5.79 ml/second), with TURP deemed superior. Surgical outcomes, such as complications and blood transfusion rates, and hospital stay were similar for both procedures. Patient-reported urinary and sexual symptoms were also similar between the arms. Qualitative interviews indicated similar patient experiences with both procedures. However, 25% of participants in the ThuVARP arm did not undergo their randomised allocation, compared with 2% of participants in the TURP arm. Prostate cancer was also detected less frequently from routine histology after ThuVARP (65% lower odds of detection) in an exploratory analysis. The adjusted mean differences between the arms were similar for secondary care NHS costs (£9 higher for ThuVARP, 95% CI -£359 to £376) and quality-adjusted life-years (0.01 favouring TURP, 95% CI -0.04 to 0.01).

LIMITATIONS

Complications were recorded in prespecified categories; those not prespecified were excluded owing to variable reporting. Preoperative Qmax and IPSS data could not be collected for participants with indwelling catheters, making adjustment for baseline status difficult.

CONCLUSIONS

TURP was superior to ThuVARP in terms of Qmax, although both operations resulted in a Qmax considered clinically successful. ThuVARP also potentially resulted in lower detection rates of prostate cancer as a result of the smaller volume of tissue available for histology. Length of hospital stay after ThuVARP, anticipated to be a key benefit, was equal to that after TURP in this trial. Overall, both ThuVARP and TURP were effective procedures for BPO, with minor benefits in favour of TURP. Therefore, the results suggest that it may be appropriate that new treatment alternatives continue to be compared with TURP.

FUTURE WORK

Longer-term follow-up to assess reoperation rates over time, and research into the comparative effectiveness of ThuVARP and TURP in large prostates.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN00788389.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 41. See the NIHR Journals Library website for further project information.

The low power effect on holmium laser enucleation of prostate (HoLEP); A comparison between 20W and 37,5W energy regarding apical enucleation efficacy and patient safety

INTRODUCTION

The Holmium laser has proven to be an invaluable tool for endoscopic prostate enucleation. The proper energy selection, during the different steps of the procedure, has always been a matter of debate. In this work we compare the effectiveness of the Holmium laser, using two different low-power energy settings, during enucleation and hemostasis (20W and 37.5W).

METHODS

One hundred and sixty patients underwent a HoLEP procedure with a 50Hz and 2J (100W) setting. During enuleation and hemostasis, two different low-power settings were applied (20W vs. 37.5W). In both groups, only the prostatic tissue in the bladder neck and enucleated tissue far away from the apex, were cut with a setting of 50Hz and 2J (100W).

RESULTS

The mean enucleation efficiency (0.78 vs. 1.2g/min-p:001) was significantly higher by utilizing 37.5W energy (group 2). Additionally, the mean enucleation rate (0.64 vs. 0.88%-P:0.001) and laser efficiency (2.07 vs. 2.12 joule/g-P:0.003) were significantly higher in group 2. The enucleation time was significantly shorter (54 vs. 75.5 mins-P:0.002), while the mean catheter removal time (27 vs. 42 hrs-P:0.008) and Hb decrease (0.5 vs. 0.6g/dl--P:0.019) were significantly lower in group 2.

CONCLUSIONS

HoLEP can be performed efficiently with 100 W-37.5W settings. Enucleation and hemostasis can be performed successfully with 37.5W, while the use of 100W during bladder neck dissection shortens the duration of the procedure.

LEVEL OF EVIDENCE

3.

The cost-effectiveness of transurethral resection of the prostate vs thulium laser transurethral vaporesection of the prostate in the UNBLOCS randomised controlled trial for benign prostatic obstruction

OBJECTIVE

To determine the cost-effectiveness of the current 'gold standard' operation of transurethral resection of the prostate (TURP) compared to the new laser technique of thulium laser transurethral vaporesection of the prostate (ThuVARP) in men with benign prostatic obstruction (BPO) within the UK National Health Service (NHS).

PATIENTS AND METHODS

The trial was conducted across seven UK centres (four university teaching hospitals and three district general hospitals). A total of 410 men aged ≥18 years presenting with either bothersome lower urinary tract symptoms (LUTS) or urinary retention secondary to BPO, and suitable for surgery, were randomised (whilst under anaesthetic) 1:1 to receive the TURP or ThuVARP procedure. Resource use in relation to the operation, initial inpatient stay, and subsequent use of NHS services was collected for 12 months from randomisation (equivalent to primary effectiveness outcome) using hospital records and patient questionnaires. Resources were valued using UK reference costs. Quality adjusted life years (QALYs) were calculated from the EuroQoL five Dimensions five Levels (EQ-5D-5L) questionnaire completed at baseline, 3- and 12-months. Total adjusted mean costs, QALYs and incremental Net Monetary Benefit statistics were calculated: cost-effectiveness acceptability curves and sensitivity analyses addressed uncertainty.

RESULTS

The total adjusted mean secondary care cost over the 12 months in the TURP arm (£4244) was £9 (95% CI -£376, £359) lower than the ThuVARP arm (£4253). The ThuVARP operation took on average 21 min longer than TURP. The adjusted mean difference of QALYs (0.01 favouring TURP, 95% CI -0.01, 0.04) was similar between the arms. There is a 76% probability that TURP is the cost-effective option compared with ThuVARP at the £20 000 per QALY willingness to pay threshold used by National Institute for Health and Care Excellence (NICE).

CONCLUSION

One of the anticipated benefits of the laser surgery, reduced length of hospital stay with an associated reduction in cost, did not materialise within the study. The longer duration of the ThuVARP procedure is important to consider, both from a patient perspective in terms of increased time under anaesthetic, and from a service delivery perspective. TURP remains a highly cost-effective treatment for men with BPO.

Endoscopic enucleation for prostate larger than 60 mL: comparison between holmium laser enucleation and plasmakinetic enucleation

PURPOSE

To compare perioperative and functional outcomes of two different energy sources, holmium laser and bipolar current for endoscopic enucleation of prostate larger than 60 mL.

METHODS

A prospective, monocentric, comparative, non-randomized study was conducted including all patients treated for prostate larger than 60 mL, measured by transrectal ultrasound. Patients were assigned to each group based on the surgeons' practice. Perioperative data were collected (preoperative characteristics, operating, catheterization and hospitalization times, hemoglobin loss, complications) and functional outcomes (IPSS, IPSS Quality of Life (QoL), PSA) at 3 months and 1 year.

RESULTS

100 patients were included in each group from October 2015 to March 2018. No differences between HoLEP and plasma groups were observed at baseline, except for mean IPSS score, IPSS QoL score and preoperative PVR that were significantly higher in the HoLEP group. Operating time (142.1 vs 122.4 min; p = 0.01), catheterization time (59.6 vs 44.4 h; p = 0.01) and hospitalization time (2.5 vs 1.8 days; p = 0.02) were significantly shorter in the plasma group. Complication and transfusion rate were no significantly different between HoLEP and plasma. No significant differences were observed concerning functional outcomes at 3 months and 1 year. The urinary incontinence rate was higher 21.1% vs 6.4% (p < 0.01) at 3 months in HoLEP group, but no difference was observed at 1 year.

CONCLUSION

Holmium and plasma are both safe and effective for endoscopic treatment for prostate larger than 60 mL. Operating, catheterization and hospitalization times were significantly shorter in the plasma group. The complication rate and functional outcomes were not significantly different.

Thulium laser transurethral vaporesection of the prostate versus transurethral resection of the prostate for men with lower urinary tract symptoms or urinary retention (UNBLOCS): a randomised controlled trial

BACKGROUND

Transurethral resection of the prostate (TURP) is the standard operation for benign prostatic obstruction. Thulium laser transurethral vaporesection of the prostate (ThuVARP) is a technique with suggested advantages over TURP, including reduced complications and hospital stay. We aimed to investigate TURP versus ThuVARP in men with lower urinary tract symptoms or urinary retention secondary to benign prostatic obstruction.

METHODS

In this randomised, blinded, parallel-group, pragmatic equivalence trial, men in seven UK hospitals with bothersome lower urinary tract symptoms or urinary retention secondary to benign prostatic obstruction were randomly assigned (1:1) at the point of surgery to receive ThuVARP or TURP. Patients were masked until follow-up completion. Centres used their usual TURP procedure (monopolar or bipolar). All trial surgeons underwent training on the ThuVARP technique. Co-primary outcomes were maximum urinary flow rate (Qmax) and International Prostate Symptom Score (IPSS) at 12-months post-surgery. Equivalence was defined as a difference of 2·5 points or less for IPSS and 4 mL per s or less for Qmax. Analysis was done according to the intention-to-treat principle. The trial is registered with the ISRCTN Registry, ISRCTN00788389.

FINDINGS

Between July 23, 2014, and Dec 30, 2016, 410 men were randomly assigned to ThuVARP or TURP, 205 per study group. TURP was superior for Qmax (mean 23·2 mL per s for TURP and 20·2 mL per s for ThuVARP; adjusted difference in means -3·12, 95% CI -5·79 to -0·45). Equivalence was shown for IPSS (mean 6·3 for TURP and 6·4 for ThuVARP; adjusted difference in means 0·28, -0·92 to 1·49). Mean hospital stay was 48 h in both study groups. 91 (45%) of 204 patients in the TURP group and 96 (47%) of 203 patients in the ThuVARP group had at least one complication.

INTERPRETATION

TURP and ThuVARP were equivalent for urinary symptom improvement (IPSS) 12-months post-surgery, and TURP was superior for Qmax. Anticipated laser benefits for ThuVARP of reduced hospital stay and complications were not observed.

FUNDING

UK National Institute for Health Research Health Technology Assessment Programme.

The impact of the laser fiber-tissue distance on histological parameters in a porcine kidney model

PURPOSE

To evaluate the impact of the fiber-tissue distance on histological parameters in a porcine kidney model.

METHODS

Four lasers were tested at 60 W using a 600-µm bare-ended fiber: a continuous wave (cw) thulium fiber laser (TFL), a super pulsed (SP) TFL, a Ho:YAG laser, and a blue diode laser (BDL). All tissue samples were mounted on a motorized XY-translation stage. The fiber-tissue distance was changed within a range from 0to 6 mm. Ten incisions were made with each laser at each distance. Afterwards, the tissue samples were sliced with a microtome for lactate dehydrogenase staining to determine zones of thermal damage.

RESULTS

In contact mode, the largest incision depth was found for the cw TFL (1.7 ± 0.1 mm) compared to the SP TFL (1.0 ± 0.1 mm), BDL (0.9 ± 0.1 mm) and HoYAG laser (1.1 ± 0.1 mm), respectively. With regard to the coagulative properties, the SP TFL and the Ho:YAG laser showed comparable coagulation depths with 0.7 ± 0.1 and 0.6 ± 0.1 mm, respectively. At 2 mm fiber-tissue distance, the Ho:YAG laser was the only laser that vaporized tissue (incision depth: 0.2 ± 0.1 mm). The BDL was the only laser that caused coagulation at a distance of 3-5 mm.

CONCLUSION

Our results support the clinical observation that cw TFL must be defocused for best coagulation, while the coagulation depth of the SP TFL remains nearly constant within the range of 0-3 mm. Increasing the distance of the laser fiber to the tissue up to 5 mm did not cause significant differences with regard to coagulation depth using the BDL.

Complications of anatomical endoscopic enucleation of the prostate

Transurethral resection of the prostate (TURP) remains the 'gold standard' for surgical treatment of benign prostatic obstruction (BPO). Recently, anatomical endoscopic enucleation of the prostate (AEEP) using holmium laser, thulium laser and plasma, etc., is extensively applied in clinical practice. However, perioperative complications of AEEP are inevitable in spite of lower incidence compared with TURP. This study reviewed the literature related to the aetiology, prevention and treatment of common complications of AEEP, which would contribute to the diagnosis and treatment of BPO.