Introduction

Prostate volume reduction has been shown to be less extensive after 120W greenlight laser vaporization (LV) than after conventional transurethral resection. Higher power and a larger beam area are the main features of the novel 180 W greenlight laser and the new MoxyTM laser fibre. LV using the 180W laser results in faster tissue ablation. However, whether 180W LV also results in more extensive tissue ablation is unknown. The aim of this study was to compare volume changes after 120W and 180W greenlight LV of the prostate.

Methods

A total of 144 patients were investigated in this prospective, non-randomized study. The 120W group consisted of 96 consecutive patients who underwent routine 120W LV between 04/2008 and 03/2012 and the 180W group of 48 consecutive patients who underwent 180W LV between 11/2012 and 11/2014. Planimetric volumetry after transrectal 3D ultrasound of the prostate was performed preoperatively, after catheter removal and after 6 weeks, 6 and 12 months. Clinical outcome parameters were recorded preoperatively and at the respective follow-up visits. Student t-test and Mann-Whitney U test were used for statistical analysis.

Results

The median initial prostate volume (120W: 46.6ml, 180W: 39.4ml; p=0.15) and the investigated baseline parameters (IPSS, QoL, Residual volume, Qmax, PSA) were not significantly different between the two groups. The operative time was significantly lower in the 180W group (120W: 82min, 180W: 70min; p<0.01). Median applied laser energy was significant lower in the 180W group (120W: 249kJ, 180W 170kJ p<0.01). After catheter removal a significant prostate volume reduction was detectable in both groups (120W: 18.5% p<0.01, 180W: 18.1% p<0.01). Subsequently, the prostate volume significantly decreased further in both groups (6 weeks: 120W: 34.4% p<0.01, 180W: 30.4% p<0.01; 6 months: 120W: 40.5% p<0.01, 180W: 38.6% p<0.01). Prostate volume reduction remained stable between 6 and 12 months (12m: 120W: 43.4% p=0.10, 180W: 38.3% p=0.20). Significant differences between the 120W and 180W group were not detectable during the 12 months observation period. In both groups the investigated outcome parameters showed a significant improvement after 6 weeks. All parameters remained stable during the 12 months observation period and were not significantly different between the two groups.

Conclusions

The higher power and increased laser beam area of the 180W laser resulted in shorter operative times but not in a more extensive tissue ablation or better functional outcome compared to the 120W laser.