Photoselective vaporization prostatectomy: experience with a novel 180 W 532 nm lithium triborate laser and fiber delivery system in living dogs.

PURPOSE: We studied vaporization parameters, and anatomical and histopathological outcomes of photoselective vaporization of the prostate with the novel GreenLight™ XPS™ 180 W, 532 nm lithium triborate laser and MoXy™ fiber in a survival model of living dogs. We compared these findings with those of the existing GreenLight HPS™ 120 W 532 nm lithium triborate laser photoselective vaporization of the prostate in living dogs. MATERIALS AND METHODS: Eight dogs underwent antegrade photoselective vaporization of the prostate with the 180 W laser delivered through a new 750 µm (vs the existing 600 µm core diameter), 50% larger, spot sized, side firing fiber. Four dogs were sacrificed 3 hours and 8 weeks postoperatively, respectively. We recorded laser energy and time. Prostates were sectioned, measured and histologically analyzed after hematoxylin and eosin, triphenyltetrazolium chloride or Gomori trichrome staining and compared with a normal control. RESULTS: Photoselective vaporization of the prostate with the 180 W laser bloodlessly created a 76% larger cavity (mean 11.8 vs 6.7 cm(3), p = 0.014), vaporized tissue at a 77% higher rate (mean 2.3 vs 1.3 cm(3) per minute, p = 0.03) and did so in 37% less time per volume vaporized (0.5 vs 0.8 minutes per cm(3), p = 0.003). Hematoxylin and eosin, and triphenyltetrazolium chloride staining histologically revealed a 33% thicker mean coagulation zone vs that of 120 W laser photoselective vaporization of the prostate (2.0 ± 0.4 vs 1.5 ± 0.3 mm, p <0.005). In prostates healed for 8 weeks postoperatively hematoxylin and eosin, and Gomori trichrome staining showed re-epithelialized cavities with negligible submucosal fibrosis compared with a normal prostate. CONCLUSIONS: GreenLight XPS 180 W 532 nm lithium triborate laser photoselective vaporization of the prostate with the MoXy fiber has a significantly higher vaporization rate and speed with a deeper hemostatic coagulation zone but favorable tissue interaction and healing equal to those of HPS 120 W laser photoselective vaporization of the prostate in dogs.

Greenlight photoselective 120-watt 532-nm lithium triborate laser vaporization prostatectomy in living canines.

PURPOSE: Efficiency, anatomic, and histopathologic outcomes of GreenLight HPS 120-W, 532-nm lithium triborate (LBO) laser photoselective vaporization of the prostate (PVP) in a survival model of living canines were studied and compared with the outcomes of the only benchmarked survival study of 60-W 532-nm potassium-titanyl-phosphate (KTP) laser PVP in living canines. MATERIALS AND METHODS: Twelve dogs underwent anterograde PVP with the 120-W LBO laser and, 4 each, were euthanized 3 hours (acute), 3 days (early), or 8 weeks (chronic) postoperatively. Laser energy and time were recorded. Prostates were sectioned, measured, and histologically analyzed after hematoxylin and eosin (H&E), triphenyltetrazolium chloride (TTC), or Gomori trichrome (GT) staining and compared with a normal control. RESULTS: LBO laser PVP at 120 W acutely created a 6.7 +/- 3.2 cm(3) cavity, hemostatically, and vaporized tissue 160% more efficiently (mean 1.3 cm(3)/min vs 0.5 cm(3)/min), 500% faster (mean 4.9 vs 29.1 min), and needed 121% less energy (mean 28.8 vs 63.6 kJ) than the 60-W KTP laser. Histologic staining with H&E and TTC demonstrated a coagulation zone of 1.5 +/- 0.3 mm for the 120-W LBO laser, comparable to the 1 to 2 mm for the 60-W KTP laser. H&E- and GT-stained, healed prostates at 8-weeks postoperatively showed reepithelialized cavities with minimal submucosal fibrosis compared with an identically stained normal and the benchmarked KTP laser PVP-treated prostates. CONCLUSION: Our in vivo canine survival study demonstrates GreenLight HPS 120-W, 532-nm LBO laser PVP has substantially more vaporization efficiency and speed, with equally favorable tissue interaction and healing vis-à-vis those benchmarked for the 532-nm wavelength by KTP laser PVP.

Laser vaporization of bovine prostate: a quantitative comparison of potassium-titanyl-phosphate and lithium triborate lasers.

PURPOSE: We compared the outcomes of in vitro vaporization of bovine prostate using the lithium triborate GreenLight HPS and the GreenLight KTP PV photoselective vaporization laser. MATERIALS AND METHODS: A total of 96 specimens of bovine prostate tissue in saline at 20C were vaporized with a 2-dimensional scanning system using a side firing fiber emitting a 532 nm wavelength at 80 W using the KTP laser, and at 80 and 120 W using the HPS laser at a working distance of 0.5 to 5 mm and a treatment speed of 2 to 8 mm per second. Dimensions of the vaporized tissue and resultant lesions were assessed. RESULTS: At a minimum working distance of 0.5 mm and a treatment speed of 4 mm per second (determined by optimum vaporization volume/energy use) the HPS laser at 80 and 120 W vaporized 50% and 100% more tissue, respectively, than the KTP laser at the customary 80 W. At the same treatment speed the HPS laser vaporized equally efficiently at up to 3 mm working distance at each power level, whereas the KTP laser lost efficiency at working distances beyond 0.5 mm. The 2 lasers vaporized more tissue at slower (longer lasing) treatment speeds but even at the slowest treatment speed mean thickness of the coagulation zone with the HPS laser at 80 and 120 W was comparable to that of the 80 W KTP laser (0.80 and 1.07 mm, respectively, vs 0.81). CONCLUSIONS: In vitro the lithium triborate GreenLight HPS 120 W laser vaporizes bovine prostate far more efficiently than the KTP photoselective vaporization laser but coagulates it equally well. These favorable outcomes must be validated in vivo.

[Photoselective vaporization with high-performance potassium-titanil-phosphate laser in the treatment of obstructive prostatic adenoma].

Novel laser technologies were used in development of a new highly effective and simple method of laser adenomectomy (LA) called photoselective vaporization of the prostate (PVP). The method employs powerful radiation from the laser on the base of potassium titanil-phosphate crystal. Laser radiation was delivered transurethrally by means of a light guide with lateral luminescence. The light guide is installed in a small-diameter channel of the cystoscope and conducts rapid vaporization of adenomic tissues in good hemostasis. Numerous international investigations showed that this method does not provoke hemorrhages, shortens drainage of the urinary bladder with urethral catheter or cathetarization can be avoided, duration of post-operative rehabilitation of the patients, is safe in terms of complications. Efficacy of PVP is comparable to transurethral resection (TUR) of prostatic adenoma but is more cost-effective than TUR or other low-invasive techniques. PVP is safe in patients with concomitant diseases and abnormal coagulation (hemophilia, anticoagulant therapy). Therefore, PVP is very promising in surgical treatment of obstructive prostatic adenoma and may become a leading surgical method in this disease.

Photoselective potassium-titanyl-phosphate laser vaporization of the benign obstructive prostate: observations on long-term outcomes.

PURPOSE: We present long-term observations on photoselective vaporization of the prostate in a prospectively studied cohort of men with obstructive benign prostatic hyperplasia. MATERIALS AND METHODS: Obstructive benign prostatic hyperplasia in 94 men was treated with transurethral near contact vaporization with potassium-titanyl-phosphate laser with the patient under general or spinal anesthesia. Baseline characteristics, perioperative data, postoperative outcomes and adverse events were recorded. RESULTS: Mean prostate volume was 45 ml (range 13 to 136). Mean lasing time was 47 minutes (range 10 to 99), and there was minimal blood loss and no evidence of fluid absorption. All 94 men were outpatients and all but 1 became catheter-free in less than 24 hours. Baseline mean American Urological Association symptom index score was 22, quality of life score 4.5, peak urinary flow rate 7.8 ml per second and post-void residual urine volume 197 ml. After surgery percentage changes from baseline in mean values of these parameters, reflecting significant (p <0.0001) improvement at 1, 2, 3 and 5 years, ranged from 83% to 88%, 86% to 90%, 170% to 252% and 76% to 89%, respectively. Complications were mild, and included transient dysuria (6%), delayed hematuria (3%), bladder neck contracture (2%) and 2-day retention (1%). No patient had incontinence or newly developed impotence, but up to 26% of the sexually active men experienced retrograde ejaculation. Postoperatively, low stage prostate cancer was detected in 5% of the patients. CONCLUSIONS: : Despite limitations our long-term experience and the literature suggest that significant improvements in symptomatic and urodynamic outcomes of photo-selective vaporization of the prostate are achievable and sustainable.

Photoselective vaporization of the prostate for the treatment of benign prostatic hyperplasia: 12-month results from the first United States multicenter prospective trial.

PURPOSE: We report the 1-year efficacy and safety of photoselective vaporization of the prostate (PVP) for symptomatic and obstructive benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A prospective clinical trial was performed in 139 men clinically diagnosed with symptomatic bladder outlet obstruction secondary to BPH who were enrolled and treated with a high power, 80 W, quasicontinuous wave potassium-titanyl-phosphate laser at 6 American medical centers across the country. Efficacy parameters were mean and percent changes from baseline in the American Urological Association Symptom Index (AUA-SI) score, quality of life score (QOL), peak urinary flow rate (Qmax), post-void residual urine volume (PVR) and transrectal ultrasound prostate volume measurement. Patients were evaluated 1, 3, 6 and 12 months following treatment. At each followup evaluation side effects were elicited. RESULTS: Significant improvements in AUA-SI score, QOL score, Qmax and PVR were noted as early as 1 month after PVP treatment. At 12 months the mean AUA-SI score decreased from 23.9 to 4.3 (p <0.0001) and the QOL score decreased from 4.3 to 1.1 (p <0.0001), while mean Qmax increased from 7.8 to 22.6 ml per second (p <0.0001). PVR decreased from 114.3 to 24.8 ml (p <0.0001), while the transrectal ultrasound volume reduction went from 54.6 ml at baseline to 34.4 ml. There was no significant blood loss or fluid absorption during or immediately after PVP. Complications consisted of transient hematuria, dysuria and urinary retention in 12 (8.6%), 13 (9.3%) and 7 (5%) patients, respectively. CONCLUSIONS: PVP is a unique, safe and effective outpatient modality that provides immediate symptomatic and urodynamic relief of bladder outlet obstruction secondary to BPH. Long-term followup is needed to validate further the maintenance of clinical efficacy beyond 1 year.

Photoselective vaporization of the prostate: initial experience with a new 80 W KTP laser for the treatment of benign prostatic hyperplasia.

PURPOSE: To study the safety and efficacy of a new high-power potassium-titanyl-phosphate laser (KTP/532; Niagara PV trade mark laser system; Laserscope, San Jose, CA) for transurethral photoselective vaporization of benign obstructive prostate tissue. PATIENTS AND METHODS: The KTP/532 laser energy at 80 W was delivered by a 6F side-firing fiber through a 23F continuous-flow cystoscope. Photoselective vaporization of the prostate (PVP) using sterile water irrigation was performed under spinal anesthesia on an outpatient basis in 10 patients with a preoperative mean prostate volume of 41.37 +/- 18.5 cc (range 24-76.3 cc). The mean lasing time was 19.8 +/- 4.9 minutes. RESULTS: Two patients experienced 1 to 7 days of mild dysuria, and one who was taking warfarin had mild transient hematuria, but none had urinary retention or other complications. The mean catheterization time was 17.2 +/- 9.6 hours (range 0-28 hours). At 1 year, the outcomes, which had showed significant improvement sustained throughout the follow-up, were as follows: mean American Urological Association Symptom Score decreased from 23.2 +/- 4.7 to 2.6 +/- 0.5 (88.8%), the mean quality of life score improved from 4.3 +/- 0.7 to 0.4 +/- 0.5 (90.7%), the mean peak urinary flow rate increased from 10.3 +/- 1.4 mL/sec to 30.7 +/- 5.8 mL/sec (198.1%), and the mean postvoiding residual volume decreased from 137.6 +/- 112.2 mL to 3.0 +/- 4.8 mL (97.8%). The mean prostate volume decreased by 27%. CONCLUSIONS: This pilot study indicates that PVP with the new 80 W KTP/532 laser is a simple, safe, and efficacious outpatient procedure for the treatment of obstructive BPH.

Primary localized amyloidosis of the bladder: experience with dimethyl sulfoxide therapy.

PURPOSE: We present our long-term experience with intravesical dimethyl sulfoxide (DMSO) for primary localized amyloidosis of the bladder. MATERIALS AND METHODS: The study included 4 males and 2 females 28 to 68 years old (mean age 54) at diagnosis of biopsy proven primary localized amyloidosis involving the bladder diffusely or extensively in 1 locale. All patients had normal upper urinary tracts. They continued to be symptomatic (hematuria in 3, irritative voiding symptoms in 1, and hematuria and irritative voiding symptoms in 2) despite conventional transurethral destructive therapy. Every 2 weeks they received 30-minute instillations of 50 ml. 50% DMSO intravesically for 3 months (patient 1), 6 months (1) and 1 year (4). RESULTS: Therapy failed at 3 and 6 months in 2 patients of whom 1 with a contracted bladder underwent cystectomy and another was stabilized for 1 year with laser therapy. In the remaining 4 patients who were followed for 6 years disease stabilized for 2 to 6 years (mean 3.5) but 3 later required additional therapy including repeat DMSO in 1 and laser therapy in 2. CONCLUSIONS: Diffuse or locally extensive bladder involvement by primary localized amyloidosis usually fails to respond to conventional transurethral destructive surgical procedures. Collectively, our experience and the literature suggest that intravesical DMSO can be a bladder saving measure and help resolve ureterovesical obstruction in some patients. High recurrence rate mandates lifelong cystoscopic surveillance.