The one year outcome after KTP laser vaporization of the prostate according to the calculated vaporized volume

Abstract

The aim of this study was to develop a new simple method for measuring the vaporized volume and to evaluate the outcome of high-power potassium-titanyl-phosphate (KTP) photoselective laser vaporization. A total of 65 patients, with a mean age of 67.7 yr (range 53 to 85), were included in the primary analysis. The vaporized volume was calculated as the pre-operative volume minus the immediate post-operative volume plus the volume of the defect. For all patients, the subjective and objective parameters improved significantly after surgery. Six and 12 months after surgery, the group with a smaller vaporized volume (<15 g) had a lower reduction of the mean International Prostate Symptom Score (P=0.006 and P=0.004) and quality of life index (P=0.006 and P=0.004) when compared to the group with a greater vaporized volume (>or=15 g). There were no differences in the change of the maximum flow rate and post-void residual based on the vaporized volume. Our findings suggest that the subjective improvement, after a high-power KTP laser vaporization, may be dependent on the vaporized volume obtained after the procedure.

Keywords: Laser Therapy; Prostate; Prostatic Hyperplasia; Vaporization.

Fig. 1

Calculated vaporized volume was determined by the formula: vaporized volume=pre-operative volume-immediate post-operative volume+defected volume. (A) transverse view (preoperative). (B) sagittal view (preoperative). (C) transverse view (postoperative). (D) sagittal view (postoperative). Arrows indicate vaporized volume immediately after photoselective vaporization of the prostate. Calculated vaporized volume was 18.7 mL (50-37+5.7). True vaporized volume was not checkable.

Fig. 2

Change in clinical parameters according to vaporized volume. (A) International Prostate Symptom Score. (B) Quality of life index. White and black circles circle indicate the scores in the groups with the vaporized volume ≥15 g and <15 g at each month, respectively. Gray and black bars indicate the score changes in the groups with the vaporized volume ≥15 g and <15 g at each month, respectively.

Fig. 3

Change in clinical parameters according to vaporized volume. (A) maximum flow rate. (B) post-void residual. White and black circles circle indicate the scores in the groups with the vaporized volume ≥15 g and <15 g at each month, respectively. Gray and black bars indicate the score changes in the groups with the vaporized volume ≥15 g and <15 g at each month, respectively.