High power potassium-titanyl-phosphate laser vaporization prostatectomy.

PURPOSE: We prospectively studied a cumulative cohort of men with obstructive benign prostatic hyperplasia who underwent potassium-titanyl-phosphate (KTP) laser vaporization prostatectomy to determine the safety and efficacy of this procedure. MATERIALS AND METHODS: A total of 55 men with symptomatic bladder outlet obstruction due to benign prostatic hyperplasia were treated with a 60 W. KTP laser produced by a prototype Laserscopedagger generator and delivered through a side-deflecting fiber with a 22Fr continuous flow cystoscope. Sterile water was used for irrigation. The prostatic lobes were vaporized to within capsular fibers. Mean lasing time plus or minus standard deviation was 44 +/- 19 minutes. RESULTS: Mean prostate volume plus or minus standard deviation was 43 +/- 14 ml. No patient had any significant blood loss or fluid absorption, or required blood transfusion. Foley catheters did not require irrigation and were removed less than 24 hours postoperatively. All patients remained satisfied with voiding outcome, which changed significantly (p <0.0001). Mean improvement in American Urological Association symptom score at 3, 6, 12 and 24-month intervals was 75%, 79%, 82% and 82%, respectively. Mean increase in peak flow rate at the same intervals was 250%, 242%, 255% and 278%, respectively. Complications included mild transient dysuria in 7%, bladder neck contracture in 2% and delayed hematuria in 4% of patients. None of the patients required re-catheterization or reoperation, or had incontinence or newly developed impotence. Of the sexually active patients 15% and 9% had retrograde ejaculation at 1 and 2 years, respectively. CONCLUSIONS: Our observation in a 2-year period indicates that 60 W. KTP laser vaporization prostatectomy is safe and effective for quickly relieving bladder outlet obstruction with minimal postoperative complications, a high rate of patient satisfaction and, to date, a generally good outcome.

High-power potassium titanyl phosphate laser vaporization prostatectomy.

In a search for potential therapeutic strategies for benign prostatic hyperplasia (BPH) that would be associated with less morbidity than transurethral resection of the prostate, various types of laser prostatectomy have been used. Although the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser allows performance of prostatectomy in an almost bloodless field and without absorption of irrigant, the remaining necrotic tissue causes bladder outlet obstruction and related symptoms for 5 to 7 days after treatment. In contrast, the potassium titanyl phosphate (KTP) laser has been found to vaporize tissue with minimal coagulation of the underlying structures. With use of the KTP laser, heat is concentrated into a small volume, the tissue is ablated by rapid vaporization of cellular water, and a 2-mm rim of coagulated tissue is left. After favorable results were obtained in studies of canine prostates and human cadavers, we implemented clinical use of 60-W KTP laser prostatectomy in selected patients. In 10 patients with symptomatic BPH who ranged in age from 52 to 80 years, outpatient KTP laser prostatectomy yielded significantly increased mean peak urinary flow rates (from 8.0 mL/s preoperatively to 19.4 mL/s within 24 hours after the procedure). No patient had hematuria, dysuria, or incontinence after removal of the catheter, and no patient required recatheterization. One patient, however, had urgency, and two other patients became febrile during the 24-hour observation period. Overall, KTP laser vaporization prostatectomy can provide immediate relief from obstructive symptoms of BPH and is not associated with dysuria.

High-power potassium-titanyl-phosphate (KTP/532) laser vaporization prostatectomy: 24 hours later.

OBJECTIVES: To study the feasibility and immediate postoperative outcome of vaporization prostatectomy by high-power potassium-titanyl-phosphate (KTP/532) laser in 10 men with bladder outlet obstruction due to benign prostatic hyperplasia (BPH) and to evaluate their clinical and voiding outcome 24 hours postoperatively. METHODS: The KTP/532 laser at 60 W was produced by a prototype Laserscope generator and delivered through a side-deflecting fiber with a 22F continuous-flow cystoscope. Sterile water was used for irrigation. The prostatic lobes were readily vaporized to within capsular fibers. The mean lasing time was 29 +/- 8 minutes, during which a mean of 104.6 +/- 30 kJ of energy was delivered. RESULTS: The prostate volumes ranged from 22 to 60 mL (mean 38.4 +/- 9.7). None of the 10 patients had any significant blood loss or any fluid absorption. Foley catheters were removed in less than 24 hours postoperatively. All patients were satisfied with their voiding outcome. The mean peak urine flow rate increased from 8 +/- 1.3 mL/s preoperatively to 19.4 +/- 8.4 mL/s (142%, P = 0.003266) 24 hours postoperatively. Postvoid residual volumes remained essentially unchanged from their preoperative levels, as expected (P = 0.767423). One patient had urgency, but none had dysuria, hematuria, or incontinence or required recatheterization. Three patients have returned for 3-month follow-up; all 3 patients have had excellent results and are very satisfied with the outcome. CONCLUSIONS: Our very early and limited experience indicates that high-power KTP/532 laser vaporization prostatectomy is feasible and appears to be safe and effective for quickly relieving bladder outlet obstruction due to BPH. Larger randomized clinical trials to compare this technique with standard transurethral resection of the prostate and more follow-up data are needed to determine its long-term efficacy and durability.

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.

Potassium-titanyl-phosphate laser vaporization of the prostate: a comparative functional and pathologic study in canines.

OBJECTIVE: We compared the functional and pathologic results of potassium-titanyl-phosphate (KTP) laser vaporization prostatectomy with those of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser vaporization and coagulation prostatectomy in dogs. METHODS: The prostates of 41 dogs were treated with KTP laser vaporization (n = 21), Nd:YAG laser vaporization (n = 10), or Nd:YAG laser coagulation (n = 10). Dogs were sacrificed 2 days or 8 weeks after treatment. Prostates were weighed, measured, serially sectioned, and whole-mounted for histologic analysis. RESULTS: All techniques were hemostatic, and no irrigant absorption was detected. KTP laser vaporization produced a prostatic defect with a mean diameter of 3.0 and 2.4 cm at 2 days and 8 weeks postoperatively, respectively. Smaller defects (P < 0.0005 at 2 days and P < 0.02 at 8 weeks) were produced by Nd:YAG laser vaporization (2.0 and 1.4 cm, respectively) and coagulation (0.5 and 0.9 cm, respectively). No dog treated with KTP laser vaporization was incontinent or developed urinary retention, including 5 dogs whose urethral catheters were removed within 24 hours of surgery. CONCLUSIONS: KTP laser vaporization prostatectomy not only provides hemostasis similar to that obtained with Nd:YAG laser coagulation, but also removes tissue at the time of operation, allowing dogs to void without straining within 24 hours of treatment. In addition, the procedure is technically simple, and the operator has excellent control over exactly which tissue is removed and which is left intact. These findings suggest that KTP laser vaporization may be useful in the treatment of human benign prostatic hyperplasia.