Early Experiences of Contact Laser Vaporization of the Prostate using the 980 nm High Power Diode Laser for Benign Prostatic Hyperplasia

Transient simulation of laser ablation based on Monte Carlo light transport with dynamic optical properties model

Laser ablation is a minimally invasive therapeutic technique to denature tumors through coagulation and/or vaporization. Computational simulations of laser ablation can evaluate treatment outcomes quantitatively and provide numerical indices to determine treatment conditions, thus accelerating the technique's clinical application. These simulations involve calculations of light transport, thermal diffusion, and the extent of thermal damage. The optical properties of tissue, which govern light transport through the tissue, vary during heating, and this affects the treatment outcomes. Nevertheless, the optical properties in conventional simulations of coagulation and vaporization remain constant. Here, we propose a laser ablation simulation based on Monte Carlo light transport with a dynamic optical properties (DOP) model. The proposed simulation is validated by performing optical properties measurements and laser irradiation experiments on porcine liver tissue. The DOP model showed the replicability of the changes in tissue optical properties during heating. Furthermore, the proposed simulation estimated coagulation areas that were comparable to experimental results at low-power irradiation settings and provided more than 2.5 times higher accuracy when calculating coagulation and vaporization areas than simulations using static optical properties at high-power irradiation settings. Our results demonstrate the proposed simulation's applicability to coagulation and vaporization region calculations in tissue for retrospectively evaluating the treatment effects of laser ablation.

[EXPERIENCES OF CONTACT LASER VAPORIZATION OF THE PROSTATE (CVP) FOR TREATING BENIGN PROSTATIC HYPERPLASIA IN THE LOCAL HOSPITAL]

(Objective) We started contact laser vaporization of the prostate (CVP) for treating benign prostatic hyperplasia at our hospital in July 2019. Forty-five patients were treated with CVP from July 2019 to April 2021. (Methods) Patients were assessed preoperatively and at one and three months after CVP treatment by using the International Prostate Symptom Score (IPSS), quality of life index (QOL index), peak urinary flow rate (Qmax), and postvoid residual urine volume (PVR). (Results) IPSS, QOL index, Qmax, and PVR significantly improved three months after CVP (p<0.05). Regarding adverse events, five patients developed early external urinary meatus strictures, two had postoperative bleeding, and three had temporary urinary retention. (Conclusions) In our hospital, elderly patients and patients who cannot discontinue an antithrombotic drug were treated by CVP for benign prostatic hyperplasia relatively safely.

Impact of Surgery for Benign Prostatic Hyperplasia on Sexual Function: A Systematic Review and Meta-analysis of Erectile Function and Ejaculatory Function

CONTEXT

Several sexual side effects, including erectile, ejaculatory, and orgasmic dysfunction, were reported with the majority of surgical procedures for benign prostatic obstruction (BPO).

OBJECTIVE

To systematically review current evidence regarding the impact of benign prostatic hyperplasia (BPH) surgery on sexual function.

EVIDENCE ACQUISITION

A comprehensive bibliographic search on the MEDLINE, Cochrane Library, Embase, Web of Science, and Google Scholar databases was conducted in July 2021. The population, intervention, comparator, and outcome (PICO) model was used to define study eligibility. Studies were Included if they assessed patients with BPO and related lower urinary tract symptoms (P) undergoing BPH surgery (I) with or without a comparison between surgical treatments (C) evaluating the impact on sexual function (O). Retrospective and prospective primary studies were included. A pooled analysis was conducted on studies including the postoperative assessment of International Index of Erectile Function (IIEF)-5, Male Sexual Health Questionnaire-Ejaculatory Dysfunction (MSHQ-EjD; Function and/or Bother), or retrograde ejaculation (RE) rate (PROSPERO database ID: CRD42020177907).

EVIDENCE SYNTHESIS

A total of 151 studies investigating 20 531 patients were included. Forty-eight randomized controlled trials evaluating 5045 individuals were eligible for the meta-analysis. In most studies (122, 80.8%), only erectile and/or ejaculatory function was evaluated. A substantial number of articles (67, 44.4%) also used nonvalidated tools to evaluate erectile and/or ejaculatory function. The pooled analysis showed no statistically significant changes in IIEF-5 score compared with baseline for the transurethral resection of the prostate (TURP; weighted mean difference [WMD] 0.76 pts; 95% confidence interval [CI] -0.1, 1.62; p = 0.08), laser procedure (WMD 0.33 pts; 95% CI -0.1, 0.77; p = 0.13), and minimally invasive treatment (WMD -1.37 pts; 95% CI -3.19, 0.44; p = 0.14) groups. A statistically significantly higher rate of RE was found after TURP (risk ratio [RR] 13.31; 95% CI 8.37, 21.17; p < 0.00001), other electrosurgical procedures (RR 34.77; 95% CI 10.58, 127.82; p < 0.00001), and the entire laser group (RR 17.37; 95% CI 5.93, 50.81; p < 0.00001). No statistically significant increase in RE rate was described after most of the minimally invasive procedures (p > 0.05). The pooled analysis of MSHQ-EjD scores was possible only for prostatic urethral lift, showing no statistically significant difference between baseline and post-treatment MSHQ-EjD Function scores (WMD -0.80 pts; 95% CI -2.41, 0.81; p = 0.33), but postoperative MSHQ-EjD Bother scores were significantly higher (WMD 0.76 pts; 95% CI 0.22, 1.30; p = 0.006).

CONCLUSIONS

Erectile function appears to be unaffected by most surgical procedures for BPO. RE is a very common adverse event of BPH surgery, although emerging minimally invasive surgical procedures could be associated with a lower risk.

PATIENT SUMMARY

Benign prostatic hyperplasia surgery can have an impact on sexual function, mainly involving ejaculatory function.

A prospective, single-center, randomized clinical trial to evaluate the efficacy of three types of laser vaporization surgeries using a 180-W GreenLight XPS laser, a 300-W diode laser, and a 200-W thulium laser for the treatment of benign prostatic hyperplasia

OBJECTIVES

This study aimed to compare the safety and efficacy of three different laser prostate vaporization surgeries, which were photoselective vaporization of the prostate (PVP), diode laser vaporization (DVP), and thulium laser vaporization (ThuVAP), for the treatment of benign prostatic hyperplasia (BPH) in a randomized clinical trial.

METHODS

A total of 71 consecutive patients with BPH were included; 23 patients were treated with PVP, 23 with DVP, and 25 with ThuVAP. Patients were evaluated with disease-related symptomatic questionnaires, Quality of Life (QOL) Index, and maximum urinary flow rate (Q_max ) for 12 months. Patients were monitored to record operation/vaporization time, 24-hour hemoglobin/sodium drop, length of catheterization/hospitalization, and perioperative/postoperative complications.

RESULTS

In all three groups, patients showed significant and comparable improvements in symptom scores, QOL Index, and Q_max during the 12-month follow-up period. The mean operation/vaporization time was equivalent across all three groups at 69/23 (PVP), 81/34 (DVP), and 76/32 minutes (ThuVAP), while the applied laser energy was lower for PVP at 157 kJ compared to the other two techniques (DVP at 358 kJ, ThuVAP at 240 kJ). The mean vaporization rates per unit energy were significantly different between the three groups (PVP 0.16, DVP 0.09, and ThuVAP 0.09 mL/kJ). There were no significant differences in the main safety profiles between the three groups.

CONCLUSIONS

Our study demonstrated that these three types of laser surgeries are similar in terms of complications and outcomes, with excellent hemostasis and high patient satisfaction. It was suggested that sufficient tissue vaporization could be achieved using less energy through PVP surgery.

Comparison of 532-nm GreenLight HPS laser with 980-nm diode laser vaporization of the prostate in treating patients with lower urinary tract symptom secondary to benign prostatic hyperplasia: a meta-analysis

To evaluate the efficacy and safety of 532-nm GreenLight HPS laser (PVP) vs 980-nm diode laser vaporization of the prostate (DVP) in treating patients with lower urinary tract symptom (LUTS) secondary to benign prostatic hyperplasia (BPH). PubMed, Cochrane Library databases, EMBASE (until Jun 2020), and original references of the included articles were searched. PRISMA checklist was followed. A total of four articles including 521 patients were studied. There was no significant difference in total operating time and lasering time of the two laser surgeries; however, a higher amount of total applied laser energy was delivered with DVP (P < 0.00001). The catheterization time after surgery in the PVP group was significantly longer than that in the DVP group (P = 0.0008), whereas the hospitalization time was significantly shorter than that in the DVP group (P = 0.02). Compared with baseline, there were significant improvements in the voiding variables over the observation period after surgery in both groups. PVP had a significant improvement in total international prostate symptom score (IPSS) (P = 0.0002) and quality of life (QoL) index (P = 0.003) compared with DVP after ≥12 months of postoperative follow-up. For complications after surgery, PVP had a larger number in needing for electrocautery to control bleeding (P = 0.02). Besides, the application of DVP resulted in a higher incidence of bladder neck contracture (P = 0.0007), dysuria (≥1 month) (P = 0.002), transient incontinence (P = 0.003), postoperative recatheterization (P = 0.02), and reoperation (P < 0.0001). The voiding parameters and micturition symptoms of patients with BPH after two kinds of laser surgery were significantly improved. However, PVP was more beneficial than DVP in terms of total IPSS, QoL index, and hospitalization time. Moreover, PVP showed a lower incidence of postoperative adverse events, but a higher risk of postoperative bleeding. PROSPERO registration number: CRD42020203222.