Thulium：YAG VapoEnucleation of the prostate in large glands： a prospective comparison using 70- and 120-W 2-μm lasers

This study compared the efficacy of 70- and 120-w 2-μm thulium：YAG VapoEnucleation of the prostate （ThuVEP） for patients with benign prostatic obstruction （BPO）. A prospective analysis of 84 patients with symptomatic BPO and prostatic enlargement （t〉 60 ml） who underwent either 70-w （n=44） or 120-w ThuVEP （n=40） non-randomly was carried out. Patient demographics and perioperative and 12-month follow-up data were analysed. The mean prostate volume was 79.90---27.49 ml in patients who had received 70-w ThuVEP, which was less than in those who had received 120-w ThuVEP （88.53＋-25.10; P=0.033）. The mean enucleation （resected weight/laser time, 2.16±1.21 g min-1 vs. 1.23±0.60 g min-1; P=-0.013）, operation efficiency （resected weight/total operation time, 0.76±0.35 g min-1 vs. 0.42＋-0.27 g min-1; P=-0.000） and percentage of resected tissue （66.93%±22.79% vs. 45.41%±23.33%; P=-0.000） were higher with 120-w treatment compared to 70-w ThuVEP. One patient （1.2% of total patients） （in the 120-w group） required a blood transfusion postoperatively. Sixty-one patients （73%） were available for review at the 12-month follow-up time point. 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 （P≤ 0.035） and were not significantly different between those treated with the different devices （70- and 120-w）. The median prostate volume reduction was 81.70% and 82.19% with 70- and 120-w ThuVEP, respectively. The incidence of complications was low and did not differ between groups treated with the different devices. Two patients （2.4%） （one per group） had a bladder neck contracture at the follow-up. ThuVEP is a safe and efficacious procedure for the treatment of symptomatic BPO. The incidence of complications was low with both devices. The 120-w thulium：YAG device enhances the effectiveness of Th,VEP with reeard to the oercentaee of resected tissue and the enucleation/ooeration efficiency.

Systematic evaluation of a holmium:yttrium-aluminum-garnet laser lithotripsy device with variable pulse peak power and pulse duration

Objective:The Holmium:yttrium-aluminum-garnet(Ho:YAG)laser is the standard lithotrite for ureteroscopy.This paper is to evaluate a Ho:YAG laser with a novel effect function in vitro,which allows a real-time variation of pulse duration and pulse peak power.Methods:Two types of phantom calculi with four degrees of hardness were made for fragmentation and retropulsion experiments.Fragmentation was analysed at 5(0.5 J/10 Hz),10(1 J/10 Hz),and 20(2 J/10 Hz)W in non-floating phantom calculi,retropulsion in an ureteral model at 10(1 J/10 Hz)and 20(2 J/10 Hz)W using floating phantom calculi.The effect function was set to 25%,50%,75%,and 100%of the maximum possible effect function at each power setting.Primary outcomes:fragmentation(mm^3),the distance of retropulsion(cm);
5 measurements for each trial.Results:An increase of the effect feature(25%vs.100%),i.e.,an increase of pulse peak power and decrease of pulse duration,improved Ho:YAG laser fragmentation.This effect was remarkable in soft stone composition,while there was a trend for improved fragmentation with an increase of the effect feature in hard stone composition.Retropulsion increased with increasing effect function,independently of stone composition.The major limitations of the study are the use of artificial stones and the in vitro setup.Conclusion:Changes in pulse duration and pulse peak power may lead to improved stone fragmentation,most prominently in soft stones,but also lead to increased retropulsion.This new effect function may enhance Ho:YAG laser fragmentation when maximum power output is limited or retropulsion is excluded.