High-power (60-watt) potassium-titanyl-phosphate laser vaporization prostatectomy in living canines and in human and canine cadavers.

OBJECTIVES: We studied the safety and efficacy of 60-W potassium-titanyl-phosphate (KTP) laser prostatectomy in living dogs and compared the efficacy with that in fresh human and dog cadavers.

METHODS: Ten dogs underwent 60-W KTP laser prostatectomy and were sacrificed 3 hours (n = 5) or 7 weeks (n = 5) after operation. Two thawed fresh-frozen human cadaver prostates and two thawed fresh-frozen canine prostates were also vaporized with the 60-W KTP laser. All prostates were weighed, measured, serially sectioned, and whole mounted for histologic analysis.

RESULTS: In dogs, the in vivo procedure was hemostatic, and no irrigant absorption was detected. Prostatic defects with a mean diameter of 3.0 and 2.5 cm at 3 hours and 7 weeks postoperatively, respectively, were produced. With experience, resection time was reduced to 14 minutes. Of the 5 dogs that were studied for 7 weeks, 4 voided immediately after removal of the urethral catheter on the morning after operation, and 1 dog required recatheterization but voided with a strong stream when the urethral catheter was removed 4 days later. All 5 dogs were continent and had normal erectile function postoperatively. Defects of 2.0 and 2.5 cm were produced in the two human cadaver prostates (weight, 29.5 and 55 g) with resection times of 26 and 54 minutes, respectively. Human and canine cadaver prostates required similar energies for tissue vaporization (15.2 and 13.7 kJ/cm3 cavity created, respectively, P > 0.6), whereas living canine prostates required only 7.0 kJ/cm3 cavity created (P < 0.01 compared with cadaver tissue).

CONCLUSIONS: The 60-W KTP laser allows technically easy, safe, rapid, and hemostatic removal of canine prostatic tissue in vivo. Furthermore, there is no difference in the efficacy of KTP laser vaporization between human and canine cadaver prostates. These findings suggest that KTP laser vaporization may be as effective in living human prostates as it is in living dogs, and thus it may be a useful technique in the surgical treatment of human benign prostatic hyperplasia.