The role of lasers in modern urology

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

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

Could Testicular Tissue Be a New Arena for the Holmium Laser?

Introduction We aimed to observe the effects of holmium:yttrium-aluminum-garnet (Ho:YAG) laser on testicular tissue. Methods An ex vivo experiment was conducted using calf testicles. A 100 W laser generator with broad-spectrum settings of 10-80 W, 20-40 Hz, and 0.5-2 J, with a medium pulse duration, was tested. The laser effects on testicular tissues with and without the tunica layer were evaluated histopathologically by calculating the incision depth (ID), vaporization area (VA), coagulation area (CA), and total laser area (TLA=VA+CA) of the specimens. Results A total of 48 experiments were conducted. In testicular tissue without a tunica layer, the highest mean ID was determined at 1 J-20 Hz (0.247±0.0208 mm) and with a tunica layer at 2 J-40 Hz (2.673±0.032 mm). In the testicular tissue without a tunica layer, the highest mean VA was determined at 1.5 J-40 Hz (0.029±0.0016 mm2) and in tissue with a tunica at 2 J-40 Hz (6.173±0.114 mm2). The highest mean TLA in tissue without a tunica was detected at 2 J-20 Hz (0.038±0.0008 mm2) and in tissue with a tunica at 2 J-40 Hz (7.292±0.07 mm2). The mean ID, VA, CA, and TLA values of all the power outputs used were found to be statistically significantly higher in the testicular tissue with the tunica layer than in that without it (p<0.001). Conclusion The Ho:YAG laser has different effects on testicular tissue with and without a tunica layer. In testicular tissue without a tunica, the laser's effect was minimal on the surrounding tissue, especially in terms of the ID, VA, and TLA. This minimal effect of the laser can be an advantage in testicular surgery procedures such as testis-sparing surgery (TSS) or testicular sperm extraction (TESE).

Preclinical optimization of a diode laser-based clamp-free partial nephrectomy in a large animal model

Kidney cancer is a common urologic malignancy with either laparoscopic (LPN) or robotic partial nephrectomy as therapeutic options of choice for localized tumors. However, renal resection and suturing are challenging steps of the procedure that can lead to complications such as prolonged warm ischemia, bleeding, and urinary fistulas. LPN with a diode laser is an efficient technique due to its cutting and/or coagulation attributes. Surprisingly, key laser features such as wavelength and power remain undefined. Using a large porcine model, we evaluated the laser range of wavelength and power in a clamp-free LPN and compared it to the established gold-standard LPN technique (i.e., cold-cutting and suturing). By analyzing surgery duration, bleeding, presence of urine leak, tissue damage related to the resected renal fragment and the remaining organ, hemoglobin levels, and renal function, we show that an optimized experimental diode laser clamp-free LPN (wavelength, 980 nm; power, 15 W) had shorter surgery time with less bleeding, and better postoperative renal function recovery when compared to the well-established technique. Together, our data indicate that partial nephrectomy with a diode laser clamp-free LPN technique is an improved alternative to the gold-standard technique. Therefore, translational clinical trials towards human patient applications are readily feasible.

Efficacy of Potassium Titanyl Phosphate Laser and Sodium Hypochlorite on Postoperative Pain Intensity Following Pulpotomy in Teeth with Symptomatic Irreversible Pulpitis: A Randomized Clinical Trial

Introduction: This study evaluated the postoperative pain intensity in permanent teeth with symptomatic irreversible pulpitis treated by pulpotomy using physiological saline, sodium hypochlorite (NaOCl), or the potassium titanyl phosphate (KTP) laser. Materials and methods: Ninety patients diagnosed with symptomatic irreversible pulpitis in permanent molars were randomly divided into three groups according to the pulpotomy procedures. Preoperative pain levels were recorded. Complete hemostasis was achieved with physiological saline (control group), NaOCl, or the KTP laser after initial bleeding control. Patients were asked to mark their pain level on the visual pain scale at 6, 24, 48, and 72 h and 7 and 30 days depending on the severity of pain. The permanent restoration was completed after 7 days. Data were statistically analyzed using Kruskal-Wallis, Mann-Whitney U, Friedman, and Bonferroni tests at a significance level of p < 0.05. Results: According to the present study, the statistical difference between the groups in terms of preoperative pain and percussion pain levels was insignificant (p > 0.05). There was no significant difference between groups in terms of demographic data (p > 0.05). The postoperative pain level of the KTP laser group was significantly lower at 6 h compared with the saline group (p < 0.05). There was no significant difference between groups in terms of the postoperative pain level at other time intervals (p > 0.05). The highest pain scores were observed in all groups at 6 h (p < 0.05). Conclusions: The KTP laser can be preferred primarily for reducing postoperative pain in pulpotomy treatments. The KTP laser or NaOCl-assisted pulpotomy can be an effective treatment for pain reduction in permanent teeth with symptomatic irreversible pulpitis. This report is registered at clinicaltrials.gov (ID: NCT05424796).

Laser accessories: surgical fibers, strippers, cleavers, and protective glasses

PURPOSE OF REVIEW

This review provides most recent findings and developments relating to surgical laser fibers, strippers, cleavers, and protective glasses.

RECENT FINDINGS

The smallest core diameter that can be used with Holmium:YAG lasers is 200 μm. Smaller core diameter fibers can be used with the Thulium fiber laser and offer better flexibility and lower risk of fracture, at the risk of greater burnback effect. Misleading discrepancies between the true diameter of laser fibers and their packaging labels must be considered. Fiber tip degradation from the burnback occurs within few minutes, thus questioning the need for time-consuming fiber tip reprocessing with fiber strippers and special cleaving tools. This shortcoming also applies to instrument-protecting ball-tip fibers. Cleavage of fiber tips through their protective jackets ('coated tips') is a cheaper alternative for instrument protection, additionally offering better visual control of the fiber tip. Third-generation side-firing greenlight laser fibers are still prone to rapid deterioration. Laser eyewear does not seem necessary for Holmium:YAG applications, whereas laser-specific protective glasses should be worn for greenlight laser applications.

SUMMARY

With better understanding of laser accessories, practicing urologists may tailor their practice to reach optimal efficacy and safety for Holmium:YAG, Thulium fiber laser and Greenlight laser applications.

Assessment of Sexual Outcomes in Patients Undergoing Thulium Laser Prostate Surgery for Management of Benign Prostate Hyperplasia: A Systematic Review and Meta-analysis

Background

Thulium laser (Tm:YAG) prostate surgery is a safe and effective procedure with low morbidity and comparable clinical outcomes to those of transurethral resection of the prostate (TURP). However, the sexual function outcomes (erectile and ejaculatory function) have been scarcely studied.

Aim

We aimed to assess the impact of Tm:YAG prostate surgery on sexual outcomes (erectile and ejaculatory function) and compare them with those patients undergoing TURP.

Material and Methods

We searched digital databases like PUBMED, SCOPUS, CENTRAL and EMBASE using relevant keywords to identify comparative studies on TURP and non-comparative studies on Tm:YAG prostate surgery that assessed sexual outcomes. We performed qualitative and quantitative analyses with the extracted data. We carried out a meta-analysis to compare postoperative International Index of Erectile Function (IIEF-5) scores and incidences of retrograde ejaculation (RE) in patients undergoing either Tm:YAG or TURP. The pre-operative and post-operative IIEF-5 scores were pooled to estimate overall scores.

Results

We included 5 comparative and 8 non-comparative studies in this review. We found the postoperative IIEF-5 score improvements to be significantly higher in the Tm:YAG prostate surgery group than in the TURP group with a significant mean difference (MD) of 0.45 (95% CI, 0.18 to 0.72; P = .001). We found no significant associations between the procedures. The pooled OR for the association of RE was estimated at 0.90 (95% CI, 0.50 to 1.60; P = .71; I² = 0%).

Conclusion

Tm:YAG prostate surgery improves erectile function more than TURP, according to our findings. Tm:YAG prostate aided surgery also outperforms TURP in terms of preserving sexual function following surgery.However, We found similar or no difference in incidence of RE between Tm:YAG prostate surgery and TURP.

Bibo L, Hao L, Pang K, et al. Assessment of Sexual Outcomes in Patients Undergoing Thulium Laser Prostate Surgery for Management of Benign Prostate Hyperplasia: A Systematic Review and Meta-analysis. Sex Med 2022;10:100483.

Safety During Ureteroscopy: Radiation, Eyes, and Ergonomics

It is known that urologic surgeons are at risk of work-place injury due to the physical requirements of operating and exposure to hazards. These hazards include radiation, exposure to body fluids, use of laser energy, and orthopedic injury due to the physical nature of operating. The risks that these hazards present can be mitigated by implementing several evidence-based safety measures. The methods to protect against radiation exposure include keeping radiation usage in the operating room as low as reasonably achievable, donning lead aprons, and wearing protective glasses. Additionally, protective glasses decrease the risk of eye injury from laser injury and exposure to body fluids. Finally, practicing sound surgical ergonomics is essential to minimize the risk of orthopedic injury and promote career longevity. The interventions discussed herein are simple and easy to implement in one's daily practice of urology.

Role of Ureteroscopy in Treatment of Upper Tract Urothelial Carcinoma

PURPOSE OF REVIEW

Upper tract urothelial carcinoma (UTUC) is uncommon accounting for less than 10% of all urothelial tumours. Ureteroscopic management (URS) is the first line treatment for low-risk disease and has been increasingly utilised due to technological advances and increasing surgical experience. This review looks at patient outcomes relating to URS, emerging technologies and the role of adjuvant intracavitary therapy in the management of UTUC.

RECENT FINDINGS

URS has firmly established itself in the management algorithm for UTUC, and a good body of evidence supports its use for low-risk disease, wherein oncological outcomes are comparable to traditional nephroureterectomy (RNU). Larger tumours can now be managed using URS with a lower morbidity than radical surgery, though with higher associated local recurrence rate and risk of progression to RNU, and as a result, patient selection and close surveillance remains key. There is limited evidence for adjuvant intracavitary therapy (Mitomycin C or BCG) in UTUC although the development of novel polymers and biodegradable stents may improve drug delivery to the upper urinary tract. URS has a clearly defined role in low-risk UTUC, and its use in larger tumours appears to be appropriate in a selected cohort of patients. The efficacy of adjuvant intracavitary therapy is as of yet undetermined, though developments in delivery techniques are promising. Likewise further developments of laser technology are anticipated to further expand the role of URS.

Prognostic Factors for the Outcome of Salivary Gland Holmium: YAG Laser Intraductal Lithotripsy

OBJECTIVES

Holmium: YAG laser has gained its popularity throughout the years and is used to treat sialolithiasis, which helps to overcome the limitations of traditional sialendoscopic lithotripsy for larger-sized salivary stones. However, little information is available regarding factors predicting the success rate of Holmium: YAG laser intraductal lithotripsy. The purpose of this study is to investigate the factors affecting the success rates of Holmium: YAG laser lithotripsy for salivary stones treatment in a tertiary care hospital.

METHODS

A retrospective study conducted in patients receiving sialolithiasis surgery under sialendoscopy from May 2013 to March 2015 at Mackay Memorial Hospital, Taiwan. Data on various factors, including patients' age, gender, glands, size of largest stone, multiple stones (≥2 stones), location of the stone (distal duct, middle duct, proximal duct, and hilum), and operative time. The success of the surgery defined as patients without any complaints such as swelling or tenderness. Logistic regression and Fisher exact tests were employed to examine these factors on the success rate.

RESULTS

Fifty-four patients who received sialendoscopy surgery with a mean age of 35.74 years old recruited. Logistic regression identified the operation time exceeding 210 minutes showed 23.497 folds higher odd ratio of having a result of operation failure (P < .05).

CONCLUSION

The prolonged operation time is the sole independent factor affecting the successful outcome for salivary gland intraductal laser lithotripsy. We recommend operative time be no more than 210 minutes to increase the success rate in salivary gland Holmium: YAG laser intraductal lithotripsy.

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.

Comparison of the Safety and Efficacy of Photoselective Vaporization of the Prostate (PVP) and Transurethral Enucleation with a Bipolar System (TUEB): A Single-Center Retrospective Study

Purpose

The aim of this study was to compare the safety and efficacy of photoselective vaporization of the prostate (PVP) and transurethral enucleation with a bipolar system (TUEB).

Patients and Methods

Patients who underwent PVP or TUEB surgery for lower urinary tract symptoms due to bladder outlet obstruction at our institution from September 2015 to May 2019 were retrospectively reviewed. A total of 83 patients (PVP: n=45, TUEB: n=38) who were available for follow-up at least 12 months after surgery were included. Preoperative characteristics, perioperative parameters, and postoperative outcomes-such as International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urinary flow rate (Qmax), post-void residual urine volume (PVR), and complications-at 3, 6, and 12 months after surgery were compared between the two groups.

Results

Although differences in age, IPSS, and QoL were not significant, a significantly greater prostate volume, lower Qmax, and greater PVR were noted in the TUEB group. In perioperative parameters, a significantly shorter operation time, less change in serum hemoglobin, fewer days of catheterization, and shorter length of stay were observed in the PVP group. As for postoperative outcomes, the IPSS storage subscore and PVR were significantly improved in the TUEB group. As complications, stress urinary incontinence was more frequently observed in the TUEB group, and urethral stricture was more common in the PVP group.

Conclusion

The present data suggest that PVP and TUEB are efficient and safe surgical treatment options. Management of patients undergoing PVP in the perioperative period appears easy. Improvements of subjective and objective parameters were superior after TUEB than after PVP.

532 nm green-light laser vaporization of upper tract urothelial carcinoma

Background

Endoscopic management of low risk upper tract urothelial carcinoma (UTUC) may be considered in select clinical scenarios, which allows sparing the morbidity of radical nephroureterectomy while achieving acceptable oncological outcomes and preservation of kidney function. Herein, we present a case with UTUC in a solitary kidney managed with 532 nm laser vaporization through a percutaneous approach.

Case presentation

The patient in this video (Additional file 1) is an 85-year-old woman who presented with a bulky tumor in the collecting system of a congenital solitary left kidney, which was a biopsy proven low grade urothelial carcinoma. Prior to the procedure, a lower pole percutaneous nephrostomy tube was successfully placed under sedation by Interventional Radiology. The procedure was done in a prone split leg position. The mass, which was predominantly localized to the renal pelvis was efficiently vaporized with the 532 nm laser in a systematic manner with continuous irrigation of normal saline through the cystoscope. The patient was discharged home on postoperative day 2 with the nephroureterostomy catheter open to drainage. This catheter was subsequently clamped and removed two weeks later without complications. Follow up uretroscopy showed excellent treatment response and the patient remains well without complications.

Conclusion

This case report details the potential utility of 532 nm laser vaporization of UTUC, however, ongoing studies are required to demonstrate peri-operative safety and durable oncologic efficacy.

Efficacy and Safety of Transurethral Laser Surgery Versus Transurethral Resection for Non-Muscle-Invasive Bladder Cancer: A Meta-Analysis and Systematic Review

OBJECTIVE

To compare the efficacy and safety of transurethral laser surgery and transurethral resection of a bladder tumor (TURBT) for non-muscle-invasive bladder cancer (NMIBC).

MATERIAL AND METHODS

A research was carried out in Medline via PubMed, EMBASE, the Cochrane Library, and Web of Science up to October 20, 2019, to identify articles related to transurethral laser surgery and TURBT for NMIBC. All analyses were done using RevMan5.3 and Stata14.

RESULTS

A total of 17 studies involving 2,439 participants were included. The analysis showed no significant difference in operation times (mean difference = -0.2; 95% CI -2.29 to 1.89; p = 0.85) or occurrences of urethral stricture (OR = 0.7; 95% CI 0.24-2.06; p = 0.52). Transurethral laser surgery was associated with a lower incidence of obturator nerve reflex (OR = 0.04; 95% CI 0.02-0.09; p < 0.00001) and bladder perforation (OR = 0.09; 95% CI 0.04-0.23; p < 0.00001), a higher rate of detrusor muscle acquisition (OR = 5.28; 95% CI 2.42-11.49; p < 0.0001), shorter catheterization (mean difference = -1.05; 95% CI -1.41 to -0.68; p < 0.00001) and hospitalization times (mean difference = -0.96; 95% CI -1.59 to -0.33; p = 0.003), and lower rates of bladder irrigation (OR = 0.21; 95% CI 0.13-0.35; p < 0.00001) and recurrence both at 12 months (OR = 0.66; 95% CI 0.48-0.9, p = 0.008) and at 24 months (OR = 0.6; 95% CI 0.41-0.86; p = 0.005).

CONCLUSIONS

Transurethral laser surgery for NMIBC, as compared to TURBT, is associated with a lower incidence of complications, a lower recurrence rate, and faster postoperative recovery.

Thulium-laser retrograde intra renal ablation of upper urinary tract transitional cell carcinoma: an ESUT Study

BACKGROUND

Radical nephroureterectomy (RNU) is the gold standard treatment for upper urinary tract urothelial carcinoma (UTUC); however, patients presenting with small low-grade UTUC have been treated by flexible ureteroscopic laser ablation with good outcomes. Different types of laser have been discussed in the literature including Holmium and Neodymium lasers. We aimed to assess the safety and efficacy of Thulium laser (Tm:YAG) in the ureteroscopic ablation of UTUC.

METHODS

A retrospective observational multicentre study of patients diagnosed with papillary UTUC between January 2015 and December 2016 was carried out. All patients underwent ureteroscopic biopsy of the UTUC followed by Tm:YAG ablation. Based on the histopathological grade of the tumor, patients were counseled to undergo either RNU (high- grade tumors) or conservative management and follow-up (low-grade tumor).

RESULTS

RNU was performed in 31 patients, while the remaining 47 patients (undergone Tm:YAG ablation only) were followed up for a mean of 11.7 months with only 19.2% of patients showing upper tract recurrence and no patients showed postoperative ureteral strictures. Limitations include the short follow-up and retrospective nature of the study.

CONCLUSIONS

On the short term, thulium Laser ablation of UTUC is safe and feasible especially in low-grade UTUC.

Transurethral endoscopic enucleation of the prostate using a diode laser versus bipolar plasmakinetic for benign prostatic obstruction: a meta-analysis

To evaluate the clinical efficacy and safety of diode laser enucleation of the prostate (DiLEP) versus bipolar plasma kinetic enucleation of the prostate (PKEP) in the management of benign prostatic hyperplasia (BPH). A systematic literature search was undertaken using PubMed, Embase, Web of Science, Cochrane Library, and CKNI databases to identify eligible studies published before April 2019. The quality of evidence and methodology was assessed. Primary outcomes were clinical and demographic characteristics and postoperative efficacy including maximum flow rate (Qmax), postvoid residual (PVR), quality of life (QoL), and International Prostate Symptom Score (IPSS); secondary outcomes were intraoperative variables and major complications. Meta-analyses of extracted data were performed with the RevMan version 5.2. The overall effects were determined by the Z-test, and a p value less than 0.05 was considered with significant difference. A fixed- or random-effect model was chosen to fit the pooled heterogeneity (determined by Chi-squared test and I²). As qualified trials were few, subgroup analyses were not performed. Four randomized controlled trials (RCTs) involving 451 patients were enrolled in our meta-analysis. In the included trials, all the diode (wavelength at 980 nm and 1470 nm) lasers applied output at continuous wave mode; the energy settings ranged from 120 to 160 W for enucleation and 30 to 60 W for coagulation. DiLEP provided less perioperative hemoglobin decrease (MD = - 3.22; 95% CI (- 5.15, - 1.29); p = 0.001; I² = 65%), less postoperative catheterization time (MD = - 17.82; 95% CI (- 32.74, - 2.90); p = 0.02; I² = 96%), less postoperative irrigation time (MD = - 7.15; 95% CI (- 13.67, - 0.62); p = 0.03; I² = 98%), and lower incidence of urinary irritative symptoms (OR = 0.31; 95% CI (0.14, 0.67); p = 0.003; I² = 0%) compared with PKEP. During the 1, 3, 6, and 12-month postoperative follow-up, no statistically significant difference was found in Qmax, IPSS, QoL, and PVR between the procedures. As regards other perioperative and postoperative parameters and major complications, we found no significant difference. Both DiLEP and PKEP are safe and efficient methods for the treatment of BPH. However, DiLEP showed less perioperative hemoglobin decrease, less postoperative catheterization time, less postoperative irrigation time, and lower rates of postoperative irritative symptoms compared with the PKEP group.

Holmium laser lithotripsy improves the rate of successful transcystic laparoscopic common bile duct exploration

Purpose

Transcystic laparoscopic common bile duct exploration (LCBDE) seems safer than transductal LCBDE and is associated with fewer biliary complications. It has traditionally been limited to smaller bile duct stones however. This study aimed to assess the ability of laser-assisted bile duct exploration by laparoendoscopy (LABEL) to increase the rate of successful transcystic LCBDE in patients with bile duct stones at the time of laparoscopic cholecystectomy.

Methods

Patients undergoing LCBDE between 2014 and 2018 were retrospectively analysed. Baseline demographic and medical characteristics were recorded, as well as intra-operative findings and post-procedure outcomes. Standard LCBDE via the transcystic route was initially attempted in all patients, and LABEL was only utilised if there was failure to achieve transcystic duct clearance. The transductal route was utilised for failed transcystic extraction.

Results

One hundred and seventy-nine consecutive patients underwent LCBDE; 119 (66.5%) underwent unaided transcystic extraction, 29 (16.2%) required LABEL to achieve transcystic extraction and 31 (17.3%) failed transcystic extraction (despite the use of LABEL in 7 of these cases) and hence required conversion to transductal LCBDE. As such, LABEL could be considered to increase the rate of successful transcystic extraction from 66.5% (119/179) to 82.7% (148/179). Patients requiring LABEL were however more likely to experience major complications (CD III–IV 5.6% vs 0.7%, p = 0.042) although none were specifically attributable to the laser intra-operatively.

Conclusions

LABEL is an effective adjunct to LCBDE that improves the rate of successful transcystic extraction.

Laser Versus Pneumatic Lithotripsy With Semi-Rigid Ureteroscope; A Comparative Randomized Study

Introduction: Ureteral stones are among the most common disorders in the urologic field. Miniaturization of endoscopic devices in urology and extracorporeal shock wave lithotripsy (ESWL) has revolutionized the management of ureteral stones. The aim of this study was to compare the efficacy and results of laser versus pneumatic lithotripsy (PL) with semi-rigid ureteroscope in a randomized prospective clinical trial in removing stones. Methods: 117 adult patients underwent transurethral lithotripsy (TUL) in a single academic center and by a single surgeon. The patients were randomized in 2 groups: In group 1, 58 patients with ureteral stones underwent ureteroscopy and stone fragmentation was done by Ho: YAG laser lithotripsy (LL) and in group 2, 59 patients underwent PL (Swiss LithoClast) by using the same ureteroscope. Results: Mean age was 41.77 years and 41.1years in group one and 2 respectively (P=0.79), there was no significant difference in male to female ratio and mean stone in both groups. The success rate for stone clearance was 79.31% and 77.96% in group 1 and 2 respectively (P=0.52). No difference between complications was seen in both groups, but the duration of operations was different (significantly lower in group 2). Conclusion: In both techniques, acceptable results were achieved. We have found a significant statistical difference in duration of operation between our results (P=0.001) and similar studies, while this was shorter in the pneumatic group in our study, it was longer in other similar ones. This might be a result of more experience in working with PL in our center.

Toward Automated In Vivo Bladder Tumor Stratification Using Confocal Laser Endomicroscopy

Purpose: Urothelial carcinoma of the bladder (UCB) is the most common urinary cancer. White-light cystoscopy (WLC) forms the corner stone for the diagnosis of UCB. However, histopathological assessment is required for adjuvant treatment selection. Probe-based confocal laser endomicroscopy (pCLE) enables visualization of the microarchitecture of bladder lesions during WLC, which allows for real-time tissue differentiation and grading of UCB. To improve the diagnostic process of UCB, computer-aided classification of pCLE videos of in vivo bladder lesions were evaluated in this study. Materials and Methods: We implemented preprocessing methods to optimize contrast and to reduce striping artifacts in each individual pCLE frame. Subsequently, a semiautomatic frame selection was performed. The selected frames were used to train a feature extractor based on pretrained ImageNet networks. A recurrent neural network, in specific long short-term memory (LSTM), was used to predict the grade of bladder lesions. Differentiation of lesions was performed at two levels, namely (i) healthy and benign vs malignant tissue and (ii) low-grade vs high-grade papillary UCB. A total of 53 patients with 72 lesions were included in this study, resulting in ∼140,000 pCLE frames. Results: The semiautomated frame selection reduced the number of frames to ∼66,500 informative frames. The accuracy for differentiation of (i) healthy and benign vs malignant urothelium was 79% and (ii) high-grade and low-grade papillary UCB was 82%. Conclusions: A feature extractor in combination with LSTM results in proper stratification of pCLE videos of in vivo bladder lesions.

The laser of the future: reality and expectations about the new thulium fiber laser-a systematic review

The Holmium:yttrium-aluminum-garnet (Ho:YAG) laser has been the gold-standard for laser lithotripsy over the last 20 years. However, recent reports about a new prototype thulium fiber laser (TFL) lithotripter have revealed impressive levels of performance. We therefore decided to systematically review the reality and expectations for this new TFL technology. This review was registered in the PROSPERO registry (CRD42019128695). A PubMed search was performed for papers including specific terms relevant to this systematic review published between the years 2015 and 2019, including already accepted but not yet published papers. Additionally, the medical sections of ScienceDirect, Wiley, SpringerLink, Mary Ann Liebert publishers, and Google Scholar were also searched for peer-reviewed abstract presentations. All relevant studies and data identified in the bibliographic search were selected, categorized, and summarized. The authors adhered to PRISMA guidelines for this review. The TFL emits laser radiation at a wavelength of 1,940 nm, and has an optical penetration depth in water about four-times shorter than the Ho:YAG laser. This results in four-times lower stone ablation thresholds, as well as lower tissue ablation thresholds. As the TFL uses electronically-modulated laser diodes, it offers the most comprehensive and flexible range of laser parameters among laser lithotripters, with pulse frequencies up to 2,200 Hz, very low to very high pulse energies (0.005-6 J), short to very long-pulse durations (200 µs up to 12 ms), and a total power level up to 55 W. The stone ablation efficiency is up to four-times that of the Ho:YAG laser for similar laser parameters, with associated implications for speed and operating time. When using dusting settings, the TFL outperforms the Ho:YAG laser in dust quantity and quality, producing much finer particles. Retropulsion is also significantly reduced and sometimes even absent with the TFL. The TFL can use small laser fibers (as small as 50 µm core), with resulting advantages in irrigation, scope deflection, retropulsion reduction, and (in)direct effects on accessibility, visibility, efficiency, and surgical time, as well as offering future miniaturization possibilities. Similar to the Ho:YAG laser, the TFL can also be used for soft tissue applications such as prostate enucleation (ThuFLEP). The TFL machine itself is seven times smaller and eight times lighter than a high-power Ho:YAG laser system, and consumes nine times less energy. Maintenance is expected to be very low due to the durability of its components. The safety profile is also better in many aspects, i.e., for patients, instruments, and surgeons. The advantages of the TFL over the Ho:YAG laser are simply too extensive to be ignored. The TFL appears to be a real alternative to the Ho:YAG laser and become a true game-changer in laser lithotripsy. Due to its novelty, further studies are needed to broaden our understanding of the TFL, and comprehend the full implications and benefits of this new technology, as well its limitations.

Efficacy and safety of laparoscopic holmium laser lithotripsy in the treatment of complicated biliary calculus: A PRISMA-compliant systematic reviews and meta-analysis

BACKGROUD

The aim of this study was to assess the efficacy and safety of laparoscopic holmium laser lithotripsy (LHLL) in the treatment of complicated biliary calculus.

METHODS

We systematically searched the electronic database (PubMed, EMBASE, Cochrane library, Web of science, and Chinese Biomedical Literature Database) up to May 2018 to identify case-controlled studies that compared LHLL with laparoscopic bile duct exploration (LBDE) for complicated biliary calculus.

RESULTS

Five case-controlled studies were included, with 541 patients (273 in the LHLL group and 268 in the LBDE group). Compared with LBDE, LHLL was associated with shorter operative time (weighted mean difference [WMD] = -40.04, P < .001) and lower estimated blood loss (EBL) (WMD = -56.42, P < .001), lesser duration of hospitalization (WMD = -3.93, P < .001) and lower rate of residual stone (OR = 0.13, P < .001). There was no statistically significant differences in bile leakage (OR = 0.48, P = .23) and hemobilia (OR = 0.49, 0.41).

CONCLUSION

Current evidence suggests that the efficacy of LHLL is superior to that of LBDE but they are similarly safe for the treatment of complicated biliary calculus. Limited by the quantity and quality of the studies included, these conclusions need to be verified by more high-quality studies.

Retained laser fiber in the nidus of a recurrent cystine urolith in an intact male English bulldog

A lithotripsy and percutaneous cystolithotomy (PCCL) were performed on a 5-year-old intact male English bulldog. The composition of the uroliths was 100% cystine. When a second PCCL was performed 2 months later, the nidus of the largest urolith was a segment of an optical fiber broken off during laser lithotripsy.

Impact of different color fiber sleeves on beam hazards of 532-nm laser and vaporization efficiency

The 532-nm laser has become increasingly popular for the treatment of urologic diseases. However, laser beam will pose significant hazards for the health of surgeons. In order to reduce beam hazards during surgery, we compared the beam hazards of laser fiber with black sleeves to the traditional fiber with transparent sleeves, and the vaporization efficiency. A total of 18 porcine kidney specimens were vaporized in normal saline at a room temperature under 532-nm laser delivered through a 760-μm core diameter side firing fiber. Two groups were divided according to the color of fiber sleeves: the transparent and the black. Each group was then divided into another three subgroups by laser power: the 80 W group, the 120 W group, and the 160 W group. The beam hazard was evaluated by light intensity measured in a sector area at a distance of 0 m, 0.5 m, and 1 m from the irradiation center. The vaporization efficiency was measured by the vaporization groove depth under the working power of 80 W, 120 W, and 160 W with a working distance of 5 mm and irradiation time of 10 s. The light intensity measured in the black fiber sleeve group is significantly lower than that in the transparent one (P < 0.01), regardless of the measuring distance (0 m, 0.5 m, and 1.0 m) and laser power (80 W, 120 W, and 160 W). No statistical difference was found on the vaporization efficiency between the groups protected by fiber sleeves of different colors (transparent/black, p > 0.05). Compared to the traditional transparent fiber sleeves, more beam hazards will be reduced in the operative region with the protection of black fiber sleeves, especially those from the irradiation center. The vaporization efficiency is not affected by the color of fiber sleeves. Such findings may offer a completely new idea for the protection of surgeons in surgeries with 532-nm lasers.

Minimally Invasive Management of Uroliths in Cats and Dogs

Urolithiasis commonly affects cats and dogs. The American College of Veterinary Internal Medicine established guidelines for the treatment of uroliths that reflect modern techniques prioritizing minimally invasive procedures with an emphasis on prevention strategies to limit morbidity and mortality. Extracorporeal shockwave lithotripsy and endoscopic nephrolithotomy constitute some of the minimally invasive treatment modalities available for upper urinary tract uroliths. Cystoscopic-guided basket retrieval, cystoscopic-guided laser lithotripsy, and percutaneous cystolithotomy are minimally invasive options for the management of lower urinary tract uroliths. Following stone removal, prevention strategies are essential to help reduce morbidity and mortality associated with stone recurrence.

Advances in Lasers for the Treatment of Stones-a Systematic Review

PURPOSE OF REVIEW

Laser lithotripsy is increasingly used worldwide and is a continuously evolving field with new and extensive research being published every year.

RECENT FINDINGS

Variable pulse length Ho:YAG lithotripters allow new lithotripsy parameters to be manipulated, and there is an effort to integrate new technologies into lithotripters. Pulsed thulium lasers seem to be a viable alternative to holmium lasers. The performance of similar laser fibers varies from manufacturer to manufacturer. Special laser fibers and "cleaving only" fiber tip preparation can be beneficial for the lithotripsy procedure. Different laser settings and the surgical technique employed can have significant impact on the success of laser lithotripsy. When safely done, complications of laser lithotripsy are rare and concern the endoscopic nature of procedure, not the technology itself, making laser lithotripsy one of the safest tools in urology. Laser lithotripsy has had several new developments and more insight has been gained in recent years with many more advances expected in the future.

LABEL procedure: Laser-Assisted Bile duct Exploration by Laparoendoscopy for choledocholithiasis: improving surgical outcomes and reducing technical failure

BACKGROUND

Laparoscopic bile duct exploration (LBDE) is recommended in current treatment guidelines for the management of choledocholithiasis with gallbladder in situ. Failure of this technique is common as a consequence of large or impacted common bile duct (CBD) stones. In this series, we present our experience in using holmium laser lithotripsy as an adjunct to LBDE for the treatment of choledocholithiasis.

METHODS

Between 2014 and 2016, eighteen laparoscopic bile duct explorations utilising holmium laser lithotripsy were performed after failure of standard retrieval techniques.

RESULTS

Choledocholithiasis was successfully treated in 18 patients using laparoscopic holmium laser lithotripsy (transcystically in 14 patients). There was one failure where a CBD stricture prevented the scope reaching the stone. Two medical complications were recorded (Clavien-Dindo I and II). There were no mortalities or re-interventions.

CONCLUSIONS

LABEL technique is a successful and safe method to enhance LBDE in cases of impacted or large stones. In our experience, this approach increases the feasibility of the transcystic stone retrieval and may reduce overall operative time.

The impact of surgical treatments for lower urinary tract symptoms/benign prostatic hyperplasia on male erectile function: A systematic review and network meta-analysis

Lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH) is common in adult men and can impair erectile function (EF). It was believed surgical treatments for this illness can improve EF due to the relief of LUTS while they were also reported harmed EF as heating or injury effect. Current network meta-analysis aimed to elucidate this discrepancy.Randomized controlled trials (RCTs) were identified. Direct comparisons were conducted by STATA and network meta-analysis was conducted by Generate Mixed Treatment Comparison. Random-effects models were used to calculate pooled standard mean difference and 95% confidence intervals and to incorporate variation between studies.Eighteen RCTs with 2433 participants were analyzed. Nine approaches were studied as transurethral resection of the prostate (TURP), plasmakinetic resection of the prostate (PKRP), plasmakinetic enucleation of the prostate (PKEP), Holmium laser enucleation of the prostate (HoLEP), Holmium laser resection of the prostate (HoLRP), photoselective vaporization of the prostate (PVP), Thulium laser, open prostatectomy (OP), and laparoscopic simple prostatectomy (LSP). In direct comparisons, all surgical treatments did not decrease postoperative International Index of Erectile Function (IIEF)-5 score except PVP. Moreover, patients who underwent HoLEP, PKEP, Thulium laser, and TURP had their postoperative EF significantly increased. Network analysis including direct and indirect comparisons ranked LSP at the highest position on the variation of postoperative IIEF-5 score, followed by PKRP, HoLEP, TURP, Thulium laser, PKEP, PVP, HoLRP, and OP. In subgroup analysis, only PVP was found lower postoperative EF in the short term and decreased baseline group, whereas TURP increased postoperative IIEF-5 score only for patients with normal baseline EF. However, HoLEP and PKEP showed pro-erectile effect even for patients with decreased baseline EF and short-term follow-up. Our novel data demonstrating surgical treatments for LUTS/BPH showed no negative impact on postoperative EF except PVP. Moreover, HoLEP and PKEP were found pro-erectile effect for all subgroups. New technologies, such as LSP, PKRP, and Thulium laser, were ranked at top positions in the network analysis, although they had no pro-erectile effect in direct comparison due to limited original studies or poor baseline EF. Therefore, further studies and longer follow-up are required to substantiate our findings.

Thulium laser treatment for bladder cancer

Recent innovations in thulium laser techniques have allowed application in the treatment of bladder cancer. Laser en bloc resection of bladder cancer is a transurethral procedure that may offer an alternative to the conventional transurethral resection procedure. We conducted a review of basic thulium laser physics and laser en bloc resection procedures and summarized the current clinical literature with a focus on complications and outcomes. Literature evidence suggests that thulium laser techniques including smooth incision, tissue vaporization, and en bloc resection represent feasible, safe, and effective procedures in the treatment of bladder cancer. Moreover, these techniques allow improved specimen orientation and accurate determination of invasion depth, facilitating correct diagnosis, restaging, and re-evaluation of the need for a second resection. Nonetheless, large-scale multicentre studies with longer follow-up are warranted for a robust assessment. The present review is meant as a quick reference for urologists.

Effect of multiple-sweeping on ablation performance during ex vivo laser nephrectomy

BACKGROUND AND OBJECTIVE

Fiber-assisted laser surgery has been employed as a minimally invasive method in various medical fields. In spite of multiple sweeping on tissue during laser treatments, the rate of tissue removal gradually decreases and eventually leads to longer irradiation times as well as deeper thermal injury. The objective of the current study was to quantitatively investigate the effect of multiple fiber sweeps on ablation performance during ex vivo 532-nm laser nephrectomy.

MATERIALS AND METHODS

Porcine kidney tissue was used to evaluate variations in tissue ablation and coagulative necrosis after pre- and multiple-sweeping with a 532 nm wavelength at various fiber speeds (2, 4, and 6 mm/second). The distance between a fiber tip and tissue surface was initially set at 1.5 mm, and no further distance change was performed. Double-integrating spheres in conjunction with an adding-doubling method were employed to measure variations in optical properties of the tested tissue. The extent of ablation and coagulation was quantified to identify the role of multiple-sweeping at various fiber conditions.

RESULTS

Optical property measurements showed a 30% decrease in light absorption but a more than threefold increase in light scattering after irreversible thermal denaturation. Pre-sweeping yielded insignificant effects on tissue coagulation due to almost consistent coagulation depths with numbers of pre-sweeps. Ablation depths increased with more numbers of fiber sweeps and slower fiber speeds whereas coagulation depths thickened primarily with the slower speeds. Multiple-sweeping induced saturation in ablation volume with the increasing numbers of multiple-sweeps irrespective of the fiber speed.

CONCLUSION

A combination of coagulation barriers, spatial distribution of power, and temporal interplay of optical energy could attribute to continuously lessen the amount of the ablated tissue with the multiple sweeps. Optical power modulation with varying fiber conditions (speed and distance) will be examined to optimize surgical parameters and to sustain the equivalent ablation performance of the first sweep with the multiple sweeping for laser nephrectomy. Lasers Surg. Med. 48:616-623, 2016. © 2016 Wiley Periodicals, Inc.