[Diode laser. Ex vivo studies on vaporization and coagulation characteristics]

Outcome of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis: a single-center retrospective study

The purpose of this study was to evaluate the efficacy of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis (RHC). We conducted a retrospective study of 21 RHC patients treated with a 980-nm diode laser between July 2014 and December 2017 at our institution. Data was collected with regard to age, sex, lower urinary tract symptoms, use of transfusions, a drop in hemoglobin levels, indication of radiotherapy, median time between radiation therapy and presentation, previous treatments, operative time, mean energy used, number of coagulated areas, catheterization time, discharge time after treatment, hospital stay, and surgical outcome. All 21 patients were women with a median age of 52 years (range 36-68 years). Eighteen patients complained of frequency and urgency, four patients had dysuria, and one patient developed urinary retention. Radiation therapy was primarily indicated in the treatment of cervical cancer in 18 patients (85.7%) and endometrial cancer in three patients (14.3%). Nine patients (42.8%) received blood transfusion before surgery and three patients (14.3%) needed blood transfusion after the procedure. The mean decrease in hemoglobin prior to the procedure was 4.08 ± 2.04 g/dL. The median length of time from completion of radiotherapy to the presentation of hematuria was 38 months (range 8-65 months). All patients had failed an adequate trial of conservative treatment which included adequate hydration, hemostatics, continuous bladder irrigation (CBI), and clot evacuation at the bedside. Eleven patients (52.4%) had previously been treated with endoscopic electrocoagulation; the mean number of procedures was 1.73 ± 0.78 (range 1-3 sessions). Six patients (28.6%) underwent HBO, and sodium hyaluronate solution irrigation was administered to 3 patients (14.3%). The mean number of HBO sessions was 26.3 ± 16.8 (range 8-50), and the mean number of sodium hyaluronate solution irrigation procedures was 4.33 ± 1.53 (range 3-6). All operations were successful. The mean operative time was 45.6 ± 12.3 min, the mean number of coagulated areas was 11.7 ± 4.4, the mean energy used was 2.74 ± 1.14 kJ, the mean catheterization time was 6.2 ± 0.9 days, the mean discharge time after treatment was 6.8 ± 1.2 days, and the average length of a hospital stay was 7.4 ± 1.3 days. In 16 patients (76.2%), hematuria was completely resolved after one session of diode laser coagulation. Four patients (19.0%) underwent multiple sessions of laser treatment due to recurrent gross hematuria (three patients required two sessions and one patient required three sessions). Only one patient (4.8%) who had persistent gross hematuria after diode laser treatment (two sessions) underwent a radical cystectomy, which resolved the hematuria. The median hematuria-free interval of patients who had multiple procedures was 9 months (range 1-13 months). In total, 21 patients underwent 27 sessions of diode laser coagulation, and the median hematuria-free interval was 16 months (range 1-45 months) with a median follow-up of 25 months (range 7-48 months). Our study shows promising results for the management of patients with RHC; however, further evaluation with a larger cohort is required to confirm the efficacy of this treatment.

Influence of 980-nm Diode Laser Vaporization on Sexual Function: A Short-Term Follow-Up Study

OBJECTIVE

The aim of this study was to assess changes in sexual function after 980-nm diode laser vaporization of the prostate.

METHODS

A total of 82 benign prostatic hyperplasia (BPH) patients underwent 980-nm diode laser vaporization from May 2013 to December 2016, and were followed up for 12 months. The following outcomes were assessed at baseline, 6, and 12 months postoperatively: international prostate symptom score (IPSS), quality of life (QoL) score, maximum urinary flow rate (Qmax), five-item version of international index of erectile dysfunction questionnaire (IIEF-5), male sexual health questionnaire ejaculatory function domain Short Form (MSHQ-EjD Short Form), and retrograde ejaculation.

RESULTS

Significant improvements at 6 and 12 months were noted postoperatively using IPSS, QoL, and Qmax compared with the preoperative values. Considering both patients and subgroups, the mean postoperative IIEF-5 scores at 6 and 12 months were unchanged compared with baseline. Regarding the MSHQ-EjD Short Form, at 6 and 12 months follow-up, postoperative total score of ejaculation function was decreased because the volume of ejaculation was decreased significantly. The frequency of ejaculation and force of ejaculation were also decreased, but the difference was not statistically significant. No significant difference in ejaculation bother item was observed after the operation. Patients with retrograde ejaculation at 6 and 12 months follow-up increased from 6/82 (7.3%) to 38/82 (46.3%), 42/82 (51.2%).

CONCLUSION

The sexual function of patients could be maintained after 980-nm diode laser vaporization of prostate with the exception of reduction of ejaculatory volume and retrograde ejaculation.

Transurethral vaporesection of prostate: diode laser or thulium laser?

This study compared the safety and effectiveness of the diode laser and thulium laser during prostate transurethral vaporesection for treating benign prostate hyperplasia (BPH). We retrospectively analyzed 205 patients with BPH who underwent a diode laser or thulium laser technique for prostate transurethral vaporesection from June 2016 to June 2017 and who were followed up for 3 months. Baseline characteristics of the patients, perioperative data, postoperative outcomes, and complications were compared. We also assessed the International Prostate Symptom Score (IPSS), quality of life (QoL), maximum flow rate (Q_max), average flow rate (AFR), and postvoid residual volume (PVR) at 1 and 3 months postoperatively to evaluate the functional improvement of each group. There were no significant differences between the diode laser and thulium laser groups related to age, prostate volume, operative time, postoperative hospital stays, hospitalization costs, or perioperative data. The catheterization time was 3.5 ± 0.8 days for the diode laser group and 4.7 ± 1.8 days for the thulium laser group (p < 0.05). Each group had dramatic improvements in IPSS, QoL, Q_max, AFR, and PVR compared with the preoperative values (p < 0.05), although there were no significant differences between the two groups. Use of both diode laser and thulium laser contributes to safe, effective transurethral vaporesection in patients with symptomatic BPH. Diode laser, however, is better than thulium laser for prostate transurethral vaporesection because of its shorter catheterization time. The choice of surgical approach is more important than the choice of laser types during clinical decision making for transurethral laser prostatectomy.

Twelve-Month Follow-up Results of Photoselective Vaporization of the Prostate With a 980-nm Diode Laser for Treatment of Benign Hyperplasia

Purpose

This study was conducted with the use of 12 months of follow-up data to evaluate the efficacy of photoselective vaporization of the prostate (PVP) with the 980-nm diode laser for the treatment of symptomatic benign prostatic hyperplasia (BPH).

Materials and Methods

The clinical data of 84 men with symptomatic BPH who underwent PVP with the 980-nm K2 diode laser between March 2010 and October 2011 were retrospectively analyzed. Postoperative parameters, including International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum urinary flow rate (Qmax), and postvoid residual volume (PVR), were assessed and compared with preoperative baseline values.

Results

Mean patient age was 72.4±6.5 years, and mean preoperative prostate volume was 47.2±16.3 g. Mean operative time was 23.3±19.1 minutes, and total amount of energy was 128±85 kJ. Mean catheterization time was 23.7±5.9 hours. At 1 month, significant improvements were noted in IPSS (11.5±6.8), QoL score (2.2±1.3), Qmax (12.9±6.5 mL/s), and PVR (41.2±31.3 mL). Three months after surgery, all postoperative follow-up parameters showed significant improvements, and the 6- and 12-month data showed sustained improvement of postoperative follow-up parameters. Bladder neck strictures were observed in 10.7% of the patients and urge incontinence in 16.6%.

Conclusions

PVP using a K2 diode laser is an effective procedure for the treatment of lower urinary tract symptoms secondary to BPH. PVP leads to an immediate and sustained improvement of subjective and objective voiding parameters. Surgeons should be vigilant for postoperative bladder neck stricture and urge incontinence.

Laser vaporization of the prostate in vivo: Experience with the 150-W 980-nm diode laser in living canines

BACKGROUND AND OBJECTIVE

Anatomic, tissue ablation and coagulation, and histopathologic outcomes of the 150-W 980-nm diode laser selective light vaporization (SLV™) of the prostate in the first survival study of living canines were analyzed.

STUDY DESIGN/MATERIALS AND METHODS

Ten dogs underwent anterograde SLV™ with the 150-W 980-nm laser delivered by its side-firing fiber (Fusion™). Postoperatively, two dogs were euthanized at 3 hours as planned, six at 2-7 days due to complications, and two, without complications, at 8 weeks as planned. 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.

RESULTS

SLV™ acutely and hemostatically created a 0.6 ± 0.3 cm(3) cavity in the 3-hour group accompanied by H&E- and TTC-identified coagulation necrosis of up to 9.5 mm (6.1 ± 1.2 mm) that led to prostatic slough-induced obstruction and perforation in six of eight (75%) surviving animals, necessitating unplanned euthanasia within 2-7 days. H&E- and GT-stained prostates at 8 weeks postoperatively showed large (9.6 ± 1.4 cm(3)) re-epithelialized prostatic cavities with persistent diffuse interstitial Prostatitis and collagenous fibrosis.

CONCLUSION

SLV™ with the 150-W 980-nm diode laser in living canines produced small cavities acutely, and was accompanied by deeply necrotic prostatic slough-induced obstruction and perforation in a majority of animals. A minority survived SLV and had favorable anatomic outcomes whereas histology revealed persisting inflammation. Further in vivo studies and a cautious clinical approach are recommended to finally evaluate the potential of SLV™ with the 150-W 980-nm diode laser.

GreenLight HPS laser 120-W versus diode laser 200-W vaporization of the prostate: comparative clinical experience

BACKGROUND AND OBJECTIVE

We present our clinical experiences of two recently introduced vaporization laser systems: the GreenLight High Performance System (HPS) laser (532 nm, 120 W) and the Diolas LFD diode laser (980 nm, 200 W).

MATERIALS AND METHODS

Two laser systems were evaluated to compare their clinical results for the treatment of benign prostatic hyperplasia (BPH). Patients were treated using either the GreenLight HPS laser (n = 84) or the diode laser (n = 55) in a prospective randomized study. The data of International Prostate Symptom Score (IPSS), maximum flow rate (Q(max)), post-void residual urine (PVR), and quality of life score (Qols) were recorded at baseline, 1-, 6-, and 12-month follow-ups. The prostate volume and prostate-specific antigen (PSA) level were assessed at baseline and 6-month follow-up. All complications were also recorded.

RESULTS

There was a statistically significant difference in IPSS, Q(max), PVR, and QoLs in each laser group at the 1-, 6-, and 12-month follow-ups compared with baseline. There was no statistical significant difference in any of these parameters at any follow-up interval between each group. The diode laser demonstrates superior hemostatic properties compared with the GreenLight HPS laser. Postoperative incontinence and postoperative irritative symptoms are more pronounced (P < 0.05) after diode laser prostatectomy. Higher incidence of dysuria with sloughing tissues and epididymitis (P < 0.05) is noted after diode laser prostatectomy. Other complications were comparable for both procedures.

CONCLUSIONS

Although both lasers can improve subjective and objective parameters of BPH, both can produce undesired effects. The search for the ideal vaporization laser to treat BPH still continues.

Preliminary results of prostate vaporization in the treatment of benign prostatic hyperplasia by using a 200-W high-intensity diode laser

OBJECTIVES

To evaluate the efficacy and safety of a 200-W high-intensity diode laser in the treatment of benign prostatic hyperplasia.

METHODS

The prostate was vaporized by using a side-firing laser fiber (diode laser: power, 150-200 W; wavelength, 980 nm; Limmer, Germany). The following parameters were assessed at baseline, and after a follow-up period of 1- and 6 months: International Prostate Symptom Score, maximum uroflow rate, postvoid residual urine volume, and quality of life score. Prostate volume and prostate-specific antigen levels were assessed at baseline and 6 months postoperatively.

RESULTS

This study included 55 patients diagnosed with lower urinary tract symptoms secondary to BPH, who were treated between December 2007 and July 2008. The recatheterization rate was 10.9%. None of these patients required a blood transfusion or had transurethral resection syndrome. Statistically significant improvements (P < .001) were observed in the values of International Prostate Symptom Score, Q(max), postvoid residual urine volume, and quality of life score at 1- and 6 months of follow-up as compared with the respective baseline values. Transient urge incontinence was noted in 8 patients (8/55, 14.5%).Sloughing of necrotic tissues was observed on cystoscopy in 8 patients within several weeks or months after the operation. The retreatment rate (secondary transurethral resection of the prostate) was 7.3%.

CONCLUSIONS

From our preliminary data, it was evident that diode laser prostatectomy can achieve excellent hemostasis, and provide immediate relief from obstructive voiding symptoms. However, the postoperative irritative symptoms and sloughing of necrotic tissues remained to be an important issue that needed to be resolved.

Prospective single-centre comparison of 120-W diode-pumped solid-state high-intensity system laser vaporization of the prostate and 200-W high-intensive diode-laser ablation of the prostate for treating benign prostatic hyperplasia

OBJECTIVE

To evaluate the safety, efficacy and short-term outcome of a new 980 nm high-intensity diode (HiDi) laser (Limmer Laser, Berlin, Germany) system in comparison to the diode-pumped solid-state laser high-performance system (HPS; GreenLight(TM), AMS, Minnetonka, MI, USA) for treating benign prostatic hyperplasia (BPH) in a prospective non-randomized single-centre study.

PATIENTS AND METHODS

From February to September 2007, 117 consecutive patients with lower urinary tract symptoms secondary to BPH were included; 62 patients were treated with 120-W HPS laser vaporization and 55 with 980-nm HiDi laser ablation of the prostate. We evaluated perioperative variables, and complications during and after surgery. Patients presenting for follow-up completed the International Prostate Symptom Score, and had their maximum urinary flow rate and postvoid residual urine volume measured.

RESULTS

The mean (sd) age of the patients was 72.3 (8.8) years (HiDi) and 73.1 (10.8) years (HPS), with a mean preoperative prostate volume of 64.7 (29.7) and 67.4 (46.9) mL, respectively. The mean operative duration was comparable, at 56.4 (20.2) and 62.7 (36.3) min, respectively, whereas the mean energy delivery was significantly higher with the diode laser, at 313 (132) vs 187 (129) kJ (P < 0.001). For patients treated with the HPS the rate of visual impairment from bleeding was higher (0% vs 12.9%, P < 0.01), as was prostate capsule perforation (0% vs 4.8%, P > 0.05). Soon after surgery the rate of dysuria (23.6% vs 17.7%, P > 0.05) and transient urge incontinence (7.3% vs 0%; P < 0.05) was higher for the HiDi laser. During the follow-up there were higher rates of bladder neck stricture (14.5% vs 1.6%, P < 0.01), re-treatment (18.2% vs 1.6%, P < 0.01) and stress urinary incontinence (9.1% vs 0%; P < 0.05) for the HiDi laser group.

CONCLUSION

Both systems investigated provide good tissue ablative properties. The HiDi laser at 980 nm is more favourable in terms of haemostasis. The penetration depths, resulting in coagulation necrosis and leading to increased re-treatment, bladder neck stricture and incontinence rates, were higher with the HiDi laser.

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.

[Laser vaporization of the prostate: all as it should be?]

Laser vaporization of the prostate currently occupies a prominent place among the surgical options for treatment of benign prostatic syndrome. Particularly the so-called GreenLight laser vaporization with the KTP (80 W) or LBO (120 W) laser has become remarkably widespread throughout the world. There are already 100 of these GreenLight laser systems in use in Germany alone. The introduction of a separate DRG for "laser vaporization" is expected to further increase the significance of this surgical technique. The aim of this study is to evaluate laser vaporization as a whole and to identify possible differences between the different lasers.