Thermal effects of thulium: YAG laser treatment of the prostate-an in vitro study

A prospective analysis of thulium laser enucleation in benign prostatic hyperplasia comparing low- and high-power approaches for prostates exceeding 80 g

INTRODUCTION AND OBJECTIVES

To compare the perioperative and functional outcomes of low-power and high-power thulium:YAG VapoEnucleation (ThuVEP) of the prostate for the treatment of large-volume benign prostatic hyperplasia (BPH) (> 80 ml).

PATIENTS AND METHODS

A prospective analysis of 80 patients with symptomatic BPO and prostatic enlargement (more than 80 ml) was conducted. They were divided randomly into two groups (40 patients in each group). One group was treated with low-power ThuVEP, and the other group was treated with high-power ThuVEP. All patients were assessed preoperatively and early postoperatively, and 12-month follow-up data were analyzed. The complications were noted and classified according to the modified Clavien classification system.

RESULTS

The mean age at surgery was 68 (± 6.1) years, and the mean prostate volume was 112 (± 20.1) cc, and there were no differences between the groups (p = 0.457). The mean operative time was 88.4 ± 11.79 min for group A and 93.4 ± 16.34 min for group B, while the mean enucleation time was 59.68 ± 7.24 min for group A and 63.13 ± 10.75 min for group B. There were no significant differences between the groups regarding catheterization time and postoperative stay. The quality of life (QoL), International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), postvoiding residual urine (PVR), and prostate volume improved significantly after treatment and were not significantly different between those treated with the different energies. The incidence of complications was low and did not differ between both the groups.

CONCLUSION

Low-power ThuVEP is feasible, safe, and effective with comparable results with high-power ThuVEP in the treatment of BPO.

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.

Temperature assessment study of ex vivo holmium laser enucleation of the prostate model

Purpose

There isscarce evidence to date on how temperature develops during holmium laser enucleation of the prostate (HoLEP). We aimed to determine the potential heat generation during HoLEP under ex vivo conditions.

Methods

We developed two experimental setups. Firstly, we simulated HoLEP ex vivo using narrow-neck laboratory bottles mimicking enucleation cavities and a prostate resection trainer. Seven temperature probes were placed at different locations in the experimental setup, and the heat generation was measured separately during laser application. Secondly, we simulated high-frequency current-based coagulation of the vessels using a roller probe.

Results

We observed that the larger the enucleated cavity, the higher the temperature rises, regardless of the irrigation flow rate. The highest temperature difference with an irrigation flow was approximately + 4.5 K for a cavity measuring 100ccm and a 300 ml/min irrigation flow rate. The higher flow rate generates faster removal of the generated heat, thus cooling down the artificial cavity. Furthermore, the temperature differences at different irrigation flow rates (except at 0 ml/min) were consistently below 5 K. Within the resection trainer, the temperature increase with and without irrigation flow was approximately 0.5 K and 3.0 K, respectively. The mean depth of necrosis (1084 ± 176 µm) achieved by the roller probe was significantly greater when using 144 W energy.

Conclusion

Carefully adjusted irrigation and monitoring during HoLEP are crucial when evacuating the thermal energy generated during the procedure. We believe this study of ours provides evidence with the potential to facilitate clinical studies on patient safety.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-04041-z.