Thulium fiber laser in urology: physics made simple

[Thulium or holmium laser or both: where will the journey take us?]

The Holmium:YAG laser has been the gold standard for laser lithotripsy over the past three decades and, since the late 1990s, also for prostate enucleation. Pulsed thulium fibre lasers (TFL) demonstrated their efficacy in in-vitro experiments and were introduced to the market a few years ago. Initial clinical results for TFL in lithotripsy and enucleation are very promising. In addition to TFL, a pulsed Thulium:YAG solid-state laser has been introduced, but clinical data for this laser are currently limited. This article aims to review the key technological differences between Ho:YAG lasers and pulsed thulium lasers and compare/discuss the initial clinical results for stone lithotripsy and laser enucleation.In-vitro studies have demonstrated the technical superiority of TFL compared with Ho:YAG lasers. However, as TFL is still a new technology, only limited studies are available to date, and optimal settings for lithotripsy have not been established. For enucleation, the differences of TFL compared with a high-power Ho:YAG laser seem to be clinically irrelevant. Initial studies on pulsed Tm:YAG lasers show good results, but there continues to be a lack of comparative studies.Based on the current literature, pulsed thulium lasers have the potential of being an alternative to Ho:YAG lasers. However, further studies are necessary to determine the optimal laser technology for enucleation and lithotripsy of urinary stones, considering all parameters, including efficacy, safety, and cost.

Influence of Prostate Volume on the Incidence of Complications and Urinary Incontinence Following Thulium Fiber Laser Enucleation of the Prostate: Results from Multicenter, Real-world Experience of 2732 patients

Background

The use of the new thulium fiber laser in enucleation of the prostate (ThuFLEP) has been introduced recently.

Objective

To evaluate complications and urinary incontinence (UI) after ThuFLEP in small and large prostate volume (PV).

Design setting and participants

We retrospectively reviewed patients who underwent ThuFLEP in six centers (from January 2020 to January 2023). The exclusion criteria were concomitant lower urinary tract surgery, previous prostate/urethral surgery, prostate cancer, and pelvic radiotherapy.

Outcome measurements and statistical analysis

Patients were divided into two groups: group 1: PV ≤80 ml; group 2: PV >80 ml. Univariable and multivariable logistic regression analyses were performed to evaluate the independent predictors of overall UI.

Results and limitations

There were 1458 patients in group 1 and 1274 in group 2. There was no significant difference in age. The median PV was 60 (61-72) ml in group 1 and 100 (90-122) ml in group 2. En bloc enucleation was employed more in group 1, while the early apical release technique was used more in group 2. The rate of prolonged irrigation for hematuria, urinary tract infection, and acute urinary retention did not differ significantly. Blood transfusion rate was significantly higher in group 2 (0.5% vs 2.0%, p = 0.001). There was no significant difference in the overall UI rate (12.3% in group 1 vs 14.7% in group 2, p = 0.08). A multivariable regression analysis showed that preoperative postvoiding urine residual (odds ratio 1.004, 95% confidence interval 1.002-1.007, p < 0.01) was the only factor significantly associated with higher odds of UI. A limitation of this study was its retrospective nature.

Conclusions

Complications and UI rates following ThuFLEP were similar in patients with a PV up to or larger than 80 ml except for the blood transfusion rate that was higher in the latter.

Patient summary

In this study, we looked at outcomes after thulium fiber laser in enucleation of the prostate stratified by PV. We found that blood transfusion was higher in men with PV >80 ml, but urinary incontinence was similar.

Laser Technology Advancements in the Treatment of Benign Prostatic Hypertrophy

PURPOSE OF REVIEW

Lasers have had a significant impact on the treatment of benign prostatic hypertrophy. This article attempts to distill the advancements in laser technology for the treatment of benign prostatic hypertrophy (BPH) into key and understandable points to help make this topic more accessible to urologists.

RECENT FINDINGS

The holmium:yttrium-aluminum-garnet (YAG) laser, one of the most significant lasers in the field of urology, has recently been improved with pulse modulating technology (Moses™ technology). New thulium:YAG technology allows both pulsed and continuous wave modes. The thulium fiber laser is one of the newer lasers to come to market and has been shown to have effective and safe outcomes. GreenLight™ lasers are predominantly used in photovaporization procedures and have also been studied extensively, although less in recent years. The modern urologist is fortunate to have many high-quality lasers and a wide variety of surgical techniques to choose from when treating BPH. Understanding the basic laser principles and applications will help urologists to select the best treatment options for their patients with BPH.

Experts' recommendations in laser use for the treatment of bladder cancer: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training and Research in Urological Surgery and Technology (TRUST)-Group

PURPOSE

To identify laser settings and limits applied by experts during laser vaporization (vapBT) and laser en-bloc resection of bladder tumors (ERBT) and to identify preventive measures to reduce complications.

METHODS

After a focused literature search to identify relevant questions, we conducted a survey (57 questions) which was sent to laser experts. The expert selection was based on clinical experience and scientific contribution. Participants were asked for used laser types, typical laser settings during specific scenarios, and preventive measures applied during surgery. Settings for a maximum of 2 different lasers for each scenario were possible. Responses and settings were compared among the reported laser types.

RESULTS

Twenty-three of 29 (79.3%) invited experts completed the survey. Thulium fiber laser (TFL) is the most common laser (57%), followed by Holmium:Yttrium-Aluminium-Garnet (Ho:YAG) (48%), continuous wave (cw) Thulium:Yttrium-Aluminium-Garnet (Tm:YAG) (26%), and pulsed Tm:YAG (13%). Experts prefer ERBT (91.3%) to vapBT (8.7%); however, relevant limitations such as tumor size, number, and anatomical tumor location exist. Laser settings were generally comparable; however, we could find significant differences between the laser sources for lateral wall ERBT (p = 0.028) and standard ERBT (p = 0.033), with cwTm:YAG and pulsed Tm:YAG being operated in higher power modes when compared to TFL and Ho:YAG. Experts prefer long pulse modes for Ho:YAG and short pulse modes for TFL lasers.

CONCLUSION

TFL seems to have replaced Ho:YAG and Tm:YAG. Most laser settings do not differ significantly among laser sources. For experts, continuous flow irrigation is the most commonly applied measure to reduce complications.

Comparison Between Thulium Fiber Laser and High-power Holmium Laser for Anatomic Endoscopic Enucleation of the Prostate: A Propensity Score-matched Analysis from the REAP Registry

BACKGROUND

Different lasers have been developed for treatment of benign prostatic hyperplasia, with no definitively superior technique identified to date.

OBJECTIVE

To compare surgical and functional enucleation outcomes in real-world multicentre practice using high-power holmium laser (HP-HoLEP) and thulium fiber laser enucleation of the prostate (ThuFLEP) for different prostate sizes.

DESIGN, SETTING, AND PARTICIPANTS

The study included 4216 patients who underwent HP-HoLEP or ThuFLEP at eight centers in seven countries between 2020 and 2022. Exclusion criteria were previous urethral or prostatic surgery, radiotherapy, or concomitant surgery.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

To adjust for the bias arising from different characteristics at baseline, propensity score matching (PSM) was used to identify 563 matched patients in each cohort. Outcomes included the incidence of postoperative incontinence, early complications (30-d), and delayed complications, and results for the International Prostate Symptom Score (IPSS), quality of life (QoL), maximum flow rate (Qmax), and postvoid residual volume (PVR).

RESULTS AND LIMITATIONS

After PSM, 563 patients in each arm were included. Total operative time was similar between the arms, but enucleation and morcellation times were significantly longer for ThuFLEP. The rate of postoperative acute urinary retention was higher in the ThuFLEP arm (3.6% vs 0.9%; p = 0.005), but the 30-d readmission rate was higher in the HP-HoLEP arm (22% vs 8%; p = 0.016). There was no difference in postoperative incontinence rates (HP-HoLEP:19.7%, ThuFLEP:16.0%; p = 0.120). Rates of other early and delayed complications were low and comparable between the arms. The ThuFLEP group had higher Qmax (p < 0.001) and lower PVR (p < 0.001) than the HP-HoLEP group at 1-yr follow-up. The study is limited by its retrospective nature.

CONCLUSIONS

This real-world study shows that early and delayed outcomes of enucleation with ThuFLEP are comparable to those with HP-HoLEP, with similar improvements in micturition parameters and IPSS.

PATIENT SUMMARY

As lasers become readily available for the treatment of enlarged prostates causing urinary bother, urologists should focus on performing good anatomic removal of prostate tissue, with the choice of laser not as important for good outcomes. Patients should be counseled about long-term complications, even when the procedure is being performed by an experienced surgeon.

Advances in lasers for the minimally invasive treatment of upper and lower urinary tract conditions: a systematic review

PURPOSE

Technological advancements in laser lithotripsy are expanding into numerous fields of urology, like ureteroscopy (URS), percutaneous nephrolithotomy (PCNL), and benign and malignant soft-tissue treatments. Since the amount of research regarding lasers in urology has grown exponentially, we present a systematic review of the most recent and relevant advances encompassing all lasers used in urological endoscopic treatment.

METHODS

We performed a literature search using PubMed (May 2023) to obtain information about lasers for urological purposes. We included only recent data from published articles between 2021 and 2023 or articles ahead of print.

RESULTS

Lasers are widely used in lithotripsy for ureteric, renal, and bladder stones, benign prostate surgery, and bladder and upper tract tumor ablation. While the holmium (Ho:YAG) laser is still predominant, there seems to be more emphasis on pulse modulation and newer lasers such as thulium fiber laser (TFL) and pulsed Tm:YAG laser.

CONCLUSION

The use of lasers and related technological innovations have shown increasing versatility, and over time have proven to be invaluable in the management of stone lithotripsy, treatment of benign and malignant prostate diseases, and urothelial tumors. Laser endoscopic treatment is heavily based on technological nuances, and it is essential to know at least the basics of these technologies. Ultimately the choice of laser used depends on its availability, cost, surgeon experience and expertise.

Experts' recommendations in laser use for the endoscopic treatment of prostate hypertrophy: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training-Research in Urological Surgery and Technology (T.R.U.S.T.)-Group

PURPOSE

To identify expert laser settings for BPH treatment and evaluate the application of preventive measures to reduce complications.

METHODS

A survey was conducted after narrative literature research to identify relevant questions regarding laser use for BPH treatment (59 questions). Experts were asked for laser settings during specific clinical scenarios. Settings were compared for the reported laser types, and common settings and preventive measures were identified.

RESULTS

Twenty-two experts completed the survey with a mean filling time of 12.9 min. Ho:YAG, Thulium fiber laser (TFL), continuous wave (cw) Tm:YAG, pulsed Tm:YAG and Greenlight™ lasers are used by 73% (16/22), 50% (11/22), 23% (5/22), 13.6% (3/22) and 9.1% (2/22) of experts, respectively. All experts use anatomical enucleation of the prostate (EEP), preferentially in one- or two-lobe technique. Laser settings differ significantly between laser types, with median laser power for apical/main gland EEP of 75/94 W, 60/60 W, 100/100 W, 100/100 W, and 80/80 W for Ho:YAG, TFL, cwTm:YAG, pulsed Tm:YAG and Greenlight™ lasers, respectively (p = 0.02 and p = 0.005). However, power settings within the same laser source are similar. Pulse shapes for main gland EEP significantly differ between lasers with long and pulse shape modified (e.g., Moses, Virtual Basket) modes preferred for Ho:YAG and short pulse modes for TFL (p = 0.031).

CONCLUSION

Ho:YAG lasers no longer seem to be the mainstay of EEP. TFL lasers are generally used in pulsed mode though clinical applicability for quasi-continuous settings has recently been demonstrated. One and two-lobe techniques are beneficial regarding operative time and are used by most experts.

Thulium fiber laser lithotripsy: Is it living up to the Hype?

Objective

The holmium:yttrium-aluminium-garnet laser (Ho:YAG) has been the gold standard for laser lithotripsy over the last three decades. After demonstrating good in vitro efficacy, the thulium fiber laser (TFL) has been recently released in the market and the initial clinical results are encouraging. This article aims to review the main technology differences between the Ho:YAG laser and the TFL, discuss the initial clinical results with the TFL as well as the optimal settings for TFL lithotripsy.

Methods

We reviewed the literature focusing on the technological aspects of the Ho:YAG laser and TFL as well as the results of in vitro and in vivo studies comparing both technologies.

Results

In vitro studies show a technical superiority of TFL compared to the Ho:YAG laser and encouraging results have been demonstrated in clinical practice. However, as TFL is a new technology, limited studies are currently available, and the optimal settings for lithotripsy are not yet established.

Conclusion

TFL has the potential to be an alternative to the Ho:YAG laser, but more reports are still needed to determine the optimal laser for lithotripsy of urinary tract stones when considering all parameters including effectiveness, safety, and costs.