Ex vivo and in vivo investigations of the novel 1,470 nm diode laser for potential treatment of benign prostatic enlargement

Perioperative haemorrhage is still the major complication of transurethral resection of the prostate (TURP) for benign enlargement of the prostate. Photoselective vaporisation of the prostate (PVP) with the potassium–titanyl–phosphate (KTP) laser has been shown to achieve instant tissue ablation with excellent haemostatic properties. Our aim was to determine the tissue removal capacity, coagulation and haemostatic property of the novel 1,470 nm diode laser, ex vivo and in vivo. We evaluated two prototype diode laser systems at 1,470 nm in an ex vivo, isolated, blood-perfused, porcine kidney model (n = 5; 10 W–50 W) and in an in vivo investigation of beagle prostate (n = 4; 100 W) to assess vaporisation capacities and coagulation properties at different generator settings. The diode laser evaluation was compared with an 80 W KTP laser in the porcine model. After the laser treatment we performed a histological examination to compare the depth of coagulation and vaporisation. The diode laser system (50 W) showed significantly lower (P < 0.0001) capacities for tissue removal than the 80 W KTP laser (0.96 mm ± 0.17 mm and 5.93 mm ± 0.25 mm, respectively, P < 0.0001), while coagulation zones were significantly (P < 0.001) larger in diode laser-treated kidneys (3,39 mm ± 0.93 mm and 1.27 mm ± 0.13 mm, respectively). In vivo, the diode laser displayed rapid ablation of prostatic tissue with no intraoperative haemorrhage. Histological examination revealed coagulation zones of 2.30 mm (±0.26) at 100 W in the diode laser-treated prostates.     

Interstitial laser coagulation treatment of benign prostatic hyperplasia: is it to be recommended?

PURPOSE: To update the clinical data on the treatment of benign prostatic hyperplasia (BPH) by interstitial laser coagulation (ILC). MATERIAL AND METHODS: In addition to recent review articles, original papers published during the last 2 years were surveyed. The focus was on prospective, particularly randomized, trials and on those with long-term follow-up. RESULTS: Interstitial laser coagulation is feasible, although considerable variability is observed in the results. Operative complications are minimal, but the postoperative catheterization time is relatively long. Irritative symptoms can last for a long time, and the rate of urinary infections is as high as 35%. There also is significant variability in the urodynamic results. The technique seems to be more effective in patients with mild bladder outlet obstruction at baseline. The retreatment rate at 1 year is as high as 15%, and higher rates, as much as 40%, are described at 3 years. When compared in a randomized fashion with transurethral resection of the prostate (TURP), the postoperative period is shorter after TURP and the retreatment rate (early and late) is higher after ILC. CONCLUSIONS: Interstitial laser coagulation is superior to TURP in terms of operative morbidity, but postoperative morbidity is higher after ILC. Long-term durability has not been properly documented, and randomized studies show a higher retreatment rate after ILC than after TURP. The technique is recommended for those patients with bleeding disorders necessitating an interventional therapy.     

Dihydrotestosterone and the concept of 5α-reductase inhibition in human benign prostatic hyperplasia

The development of human benign prostatic hyperplasia (BPH) clearly requires a combination of testicular androgens and the ageing process. Although the role of androgens as the causative factor for human benign prostatic hyperplasia is debated, they undoubtedly play, at least, a permissive role. The principal prostatic androgen is dihydrotestosterone. Although not elevated in human benign prostatic hyperplasia, dihydrotestosterone levels in the prostate remain at a normal level with ageing, despite a decrease in the plasma testosterone. Dihydrotestosterone (DHT) is generated by a reduction in testosterone. Two isoenzymes of 5alpha-reductase have been discovered. Type 1 is present in most tissues in the body where 5alpha-reductase is expressed, and is the dominant form in sebaceous glands. Type 2 5alpha-reductase is the dominant isoenzyme in genital tissues, including the prostate. Finasteride is a 5alpha-reductase inhibitor that has been used to treat BPH and male-pattern baldness. At doses used clinically, its major effect is to suppress type 2 5alpha-reductase, because it has a much lower affinity for the type 1 isoenzyme. Finasteride suppresses DHT by about 70% in serum and by as much as 85%-90% in the prostate. The remaining DHT in the prostate is likely to be the result of type 1 5alpha-reductase. The suppression of both 5alpha-reductase isoenzymes with GI198745 results in greater and more consistent containment of serum dihydrotestosterone than that observed with a selective inhibitor of type 2 5alpha-reductase. Physiological and clinical studies comparing dual 5alpha-reductase inhibitors, such as GI198745, with selective type 2, such as finasteride, will be needed to determine the clinical relevance of type 1 5alpha-reductase within the prostate. There have been two large, international multicentre, phase III trials published documenting the safety and efficacy of finasteride in treating human benign prostatic hyperplasia. Combining these two studies, randomised, controlled data are available for 12 months. Non-controlled extension of these data from a subset of patients, who elected to continue on the drug for 3, 4 and 5 years, are also available. Long-term medical therapy with finasteride can reduce clinically significant endpoints, such as acute urinary retention or surgery. According to the meta-analysis of six randomised, clinical trials with finasteride, finasteride is most effective in men with large prostates. A more effective dual inhibitor of type 1 and 2 human 5alpha-reductase may lower circulating dihydrotestosterone to a greater extent than finasteride and show advantages in treating human benign prostatic hyperplasia and other disease states that depend on dihydrotestosterone. A clinical evaluation of potent dual 5alpha-reductase inhibitors may help to define the relative roles of human type 1 and 2 5alpha-reductase in the pathophysiology of benign prostatic hyperplasia and other androgen-dependent diseases.     

α-Adrenoceptors and benign prostatic hyperplasia: basic principles for treatment with α-adrenoceptor antagonists

The selective blockade of alpha1-adrenoceptors (ARs) is now a well-accepted and widely used treatment for patients presenting with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and bladder outlet obstruction. The sites of action of the currently used alpha1-AR antagonists when relieving LUTS have not yet been established, but it seems clear that effects on prostatic as well as non-prostatic tissues are important. Alpha1-ARs in the bladder, urethra, and vas deferens, on ganglia and nerve terminals, and in the central nervous system (CNS) may all influence LUTS and the clinical effects of alpha1-AR antagonists. The relevance of alpha1-AR subtype selectivity for the clinical usefulness of existing drug therapy has still not been clarified, but it cannot be dismissed that blockading both alpha1A- and alpha1D-ARs is necessary for optimal clinical effect. Despite the above uncertainties, there seems to be a consensus that clinically available alpha1-AR antagonists provide a safe, effective and generally well-tolerated therapy for patients with LUTS.     

The efficacy and safety of 2-μm continuous laser in the treatment of high-risk patients with benign prostatic hyperplasia

Two-micrometer laser resection of prostate-tangerine technique dissects whole prostatic lobes off the surgical capsular, similar to peeling a tangerine. The present study aimed to evaluate the safety and efficacy of 2-μm continuous laser vaporization in the treatment of high-risk patients with benign prostatic hyperplasia (BPH) during the 24-month follow-up. The study included 248 patients with moderate to severe lower urinary tract symptoms who underwent 2-μm continuous laser vaporization of the prostate. All patients were accompanied with different degree comorbidities and 94 patients were taking oral anticoagulants. BPH was successfully treated with 2-μm continuous laser vaporization in all patients. Mean pre-operative prostate volume was 76?±?25.3 ml and mean operative time was 49.8?±?16.5 min. There were no major complications intra-operatively or postoperatively, and no blood transfusions were needed. About 20 patients (8.1%) needed bladder irrigation postoperatively. Average catheterization time was 2.0?±?1.8 days (range 1–5 days). Four patients required reoperation due to enlarged prostates from residual adenoma. At 3-, 6-, 12-, and 24-month follow-ups, maximum urinary flow rates (Qmax) increased from 6.9?±?1.7 to 19.1?±?4.2, 19.5?±?4.6, 19.4?±?4.6, and 19.5?±?4.1 ml/s, respectively. Mean International Prostate Symptom Scores (IPSS) decreased from 27.6?±?5.1 (pre-operation) to 9.2?±?2.6, 7.12?±?1.42, 6.18?±?1.32, and 6.25?±?1.30 at 3-, 6-, 12-, and 24-month post-operation, respectively. Two-micrometer continuous laser vaporization is a safe and effective surgical endoscopic technique associated with low complication rate in BPH patients at high risk and those on anticoagulation therapy who have severe LUTS caused by BPH.     

Nomenclature in thulium laser treatment of benign prostatic hyperplasia: it’s time to pull the rabbit out of the hat

Lasers in Medical Science - We performed a narrative review with the focus on laser settings and surgical procedure with thulium laser. Our primary goal was to define the most valid settings of...     

Prostatic artery embolization for the treatment of symptomatic benign prostatic hyperplasia in men ≥75 years: a prospective single-center study

Purpose

To compare the safety and efficacy of PAE for the treatment of benign prostatic hyperplasia (BPH) in men ≥75 years, who we defined as elderly, to those <75 years.

Methods

A total of 157 patients diagnosed with lower urinary tract symptoms (LUTS) due to BPH underwent PAE. Group A (n = 52) included patients ≥75 years, and group B (n = 105) included patients <75 years. Follow-up was performed using the International Prostate Symptoms Score (IPSS), quality of life (QoL), peak urinary flow rate (Q _max), post-void residual volume (PVR), the International Index of Erectile Function short form (IIEF-5), prostatic-specific antigen (PSA), and prostate volume (PV), at 1, 3, 6, and every 6 months thereafter.

Results

More coexistent systemic diseases were identified in group A than in group B (P < 0.05). Technical success rate of PAE was 90.4 % in group A and 95.2 % in group B (P = 0.06). A total of 147 patients had completed the follow-up with a mean of 20 months. Compared with the baseline, there were significant improvements in IPSS, QoL, Q _max, PV, PVR, and PSA in both groups after PAE. There were no significant differences in the changes of IPSS, Q _max, PVR, PSA, and IIEF-5 between groups after PAE. No major complications were noted.

Conclusion

PAE could be used as an effective, safe, and well tolerable method in the treatment of elderly symptomatic BPH patients, similarly to younger patients, and it may play an important role in patients in whom medical therapy has failed, who are at high surgical and anesthetic risk or who refuse the standard surgical therapy.

     

Preliminary results of development of a single-mode Q-switched Nd: YAG ring laser at 213 nm and its application for the microsurgical dissection of retinal tissue ex vivo

The Nd: YAG laser family offers wide possibilities for surgery applications in medicine. The radiation at 213 nm provides similar tissue effects as compared to 193 nm excimer lasers, but offers considerable practical advantages in the operating room. As such, it is of considerable interest to create single-mode Q-switched fifth harmonic Nd: YAG pulsed lasers with a high coefficient of efficiency and low divergence. Parameters of the ring three-mirror anisotropic cavity TEM₀₀-Nd: YAG laser were calculated on the basis of the analysis of Gaussian beam behavior in the three-mirror ring cavity, with one convex spherical mirror and one intracavity positive lens. On the hand of numerical calculations a prototype of a single-mode Q-switched Nd: YAG-213 nm laser with an output energy of 4 mJ and a beam divergence of 1 mrad has been developed. At a pulse repetition rate of 50 Hz, it has a generation efficiency in the Q-switched mode of 0,6%. A hollow core wave guide is used in combination with a short length of a special fused silica optical fiber to guide the laser beam. Full-depth dissection of rabbit retina ex vivo was achieved at the intensities of 0.18–0.05 J/cm² and a repetition rate of 50 Hz, with a linear cutting rate of 6 mm/s. Although the retina was completely cut, heat necrosis of the choroid did not occur. We are currently in the process of testing the dissection of retinal tissue during retinotomy, and the formation of holes in the trabecular meshwork in glaucoma surgery.     

The impact of minimally invasive surgeries for the treatment of symptomatic benign prostatic hyperplasia on male sexual function： a systematic review

A systematic review of randomized controlled trials and cohort studies was conducted to evaluate data for the effects of minimally invasive procedures for treatment of symptomatic benign prostatic hyperplasia （BPH） on male sexual function. The studies searched were trials that enrolled men with symptomatic BPH who were treated with laser surgeries, transurethral microwave therapy （TUMT）, transurethral needle ablation of the prostate （TUNA）, transurethral ethanol ablation of the prostate （TEAP） and high-intensity frequency ultrasound （HIFU）, in comparison with traditional transurethral resection of the prostate （TURP） or sham operations. A total of 72 studies were identified, of which 33 met the inclusion criteria. Of the 33 studies, 21 were concerned with laser surgeries, six with TUMT, four with TUNA and two with TEAP containing information regarding male sexual function. No study is available regarding the effect of HIFU for BPH on male sexual function. Our analysis shows that minimally invasive surgeries for BPH have comparable effects to those of TURP on male erectile function. Collectively, less than 15.4% or 15.2% of patients will have either decrease or increase, respectively, of erectile function after laser procedures, TUMT and TUNA. As observed with TURP, a high incidence of ejaculatory dysfunction （EjD） is common after treatment of BPH with holmium, potassium-titanyl-phosphate and thulium laser therapies （〉 33.6%）. TUMT, TUNA and neodymium：yttrium aluminum garnet visual laser ablation or interstitial laser coagulation for BPH has less incidence of EjD, but these procedures are considered less effective for BPH treatment when compared with TURP.     

Pharmacoeconomic evaluation of combination therapy with dutasteride and α1 blocker for treatment of benign prostatic hyperplasia in Japan

The cost-effectiveness of combination therapy with an α1 blocker and dutasteride in benign prostatic hyperplasia (BPH) was analyzed in comparison with α1 blocker monotherapy. A Markov model with seven health states related to BPH was constructed with 4-year and 10-year time horizons and from the entire payers perspective. The transition probabilities among different health states input into the model were mainly derived from CombAT Study data, while cost parameters were estimated from a clinical database including DPC claims. Effectiveness was defined as quality adjusted life year (QALY). The cost-effectiveness of combination therapy was assessed by the incremental cost-effectiveness ratio (ICER) threshold (6 to 7 million Japanese yen (JPY)/QALY gained). For a base-case analysis, combination therapy produced an incremental effectiveness versus monotherapy of 0.050 and 0.097 QALYs at 4 years and 10 years, respectively, while the concomitant incremental costs were estimated to be 257,172 and 579,908 JPY, respectively. The ICERs for combination therapy versus monotherapy calculated at 4 years and 10 years were 5,119,007 and 5,974,495 JPY/QALY gained, respectively, both below the acceptable ICER threshold. Sensitivity analyses revealed that the ICER tended to decrease with greater BPH severity. These findings suggest that combination therapy with an α1 blocker and dutasteride would be more cost-effective in BPH than α1 blocker monotherapy and more efficient in moderate-to-severe BPH.     

Human papilloma virus lesions of the oral cavity: healing and relapse after treatment with 810–980 nm diode laser

Lasers in Medical Science - This study evaluated the therapeutic efficacy of laser therapy in treating oral human papilloma virus (HPV) lesions. In particular, mode of action, healing,...     

An 810 nm diode laser in the treatment of small (≤1.0 mm) leg veins: a preliminary assessment

A consistently effective treatment for small leg veins ( 1.0 mm) is still being sought. The efficacy of an 810 nm diode laser in vein removal was assessed in a preliminary study. Fifteen females, skin types I to III, vein diameters 0.5–1 mm, aged from 25 to 42 years, participated in the study. An 810 nm diode laser (90 W, 20 ms/pulse, 10 Hz rep rate, 4.0 mm hand piece) was applied along the target veins. Biopsies were taken from two patients before and after the first treatment session. No compression was applied post-treatment. Four weeks later, a second treatment was given. Results were assessed subjectively from the patients satisfaction index (SI) and objectively from clinical photography done by an independent clinician, who also judged the venous morphology before and 4 weeks after the second session. All patients completed the trial. Pain was moderate to severe at the time of treatment and erythema which was mild, which was seen in all 15 patients; oedema occurred in 12 patients and blistering in only one. No scarring was noticed. The overall satisfaction indices at the 4- and 8-week assessments were 20.7% and 55.1%, respectively. No patient got worse. The objective evaluations at the 4- and 8-week assessments showed increasing improvement in all aspects examined. Pain at the time of treatment was a problem for all patients, so epidermal cooling should be added. Despite this, the 810 laser diode was an interesting and promising device for treatment of small leg veins, warranting further study in larger patient cohorts with a longer-term follow up.