High-power potassium-titanyl-phosphate laser fibres for endovaporization of benign prostatic hyperplasia: how much do they deteriorate during the procedure?

A Novel Method for GreenLight MoXy Laser Fiber Irrigation System to Improve Performance and Durability: A New Standard of Care?

Introduction and Objectives: The GreenLight™ MoXy^® laser fiber has been used since 2010 for benign prostatic hyperplasia procedures. We tested a novel principle to increase the saline irrigation flow rates beyond the current standard of gravity drip (∼22 cc/minutes) within the fiber-attached cooling system to potentially prevent excessive tissue adherence and to eliminate the likelihood of degradation due to abnormal overheating. The objective was to assess differences between the ordinary and active pumping methods with ≥2 times flow rate after conditioning of the laser fiber. Materials and Methods: A controllable full, tissue-contact system was utilized for conditioning in a porcine model, applying 180 W of vaporization mode of GreenLight XPS console for 30 continuous minutes. Four groups were evaluated using different saline flow rates; the nominal flow rate (control group, 22 mL/minute), digital pump set (35 mL and 50 mL/minute), and a manual pressure cuff with hand pump set using a 3-L saline bag with pressure of 300 mmHg (35-80 mL/minute). At the end of the conditioning process, a mechanical pull force test was executed on the fiber metal cap to evaluate the bonding strength. A failed event was defined as the natural detachment of the metal cap during the conditioning process or a cap pull force smaller than 22.24 N resulting in detachment. Additional physical parameters, including fiber tip temperature information and laser beam power transmission efficiency, were analyzed. Results: Detachment of the cap occurred less frequently when using the 300 mmHg pressure cuff saline bag compared to the nominal flow rate (6.67% vs 50%, respectively). The average operating fiber tip temperatures were lower in the higher flow rate groups compared to nominal, measured at 315°C and 305°C. compared to 442°C. Moreover, a significantly lower FiberLife Event count and an ∼5% increase of the average final laser transmission efficiency were observed in the higher flow rate groups. Conclusions: Our study demonstrates superior results when using active pumping or high-pressure systems to increase saline flow rates in terms of laser fiber durability without any additional cost. More specifically, use of a manual pressure cuff with starting pressure at 300 mmHg, a system that is readily available in most operating rooms, increases MoXy fiber durability. Further studies are required to assess if this technique will improve user experience, clinical outcomes, and procedure costs.

Is loss of power output due to laser fiber degradation still an issue during prostate vaporization using the 180 W GreenLight XPS laser?

PURPOSE

To investigate whether heat-induced fiber degradation and loss of power output, which occurred during GreenLight laser vaporization (LV) of the prostate using the first- and second-generation 80 and 120 W laser, are still an issue during LV using the upgraded third generation 180 W GreenLight XPS™ laser.

METHODS

Laser beam power output of 53 laser fibers was measured at baseline and after every 25 kJ of delivered energy during routine 180 W GreenLight XPS™ LV in 47 patients with prostatic bladder outflow obstruction. After the procedures, the fiber tips were microscopically examined.

RESULTS

The median applied energy per patient was 178 kJ [interquartile range (IQR): 106-247]. Loss of power output during the procedure was detectable in all fibers. After the application of 25, 150, and 250 kJ, the median power output decreased to 77% (IQR 59-87), 57% (IQR 32-71), and 51% (IQR 37-64) of the baseline value. Nine fibers (17%) remained on a relatively high power output level (> 80% of the initial output), while 13 fibers (25%) showed an end-of-procedure power output of less than 20%. Microscopy of the fiber tip revealed mild-to-moderate overall degradation and increasing degradation with higher energy delivered.

CONCLUSION

Despite changes in fiber design, heat-induced fiber damage and loss of power output remain an issue during 180 W GreenLight XPS™ LV. Whether modifications of the surgical technique can prevent impairment of fiber performance needs to be further evaluated.

Photoselective Vaporesection of the Prostate via an End-firing Lithium Triborate Crystal Laser

The occurrence of lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) is a common problem with a high incidence in the aging male population. Although it is not a life-threatening disease, BPH causes problems that seriously impact the quality of life. Here, we introduce a new technique called photoselective vaporesection of the prostate (PVRP) in treating BPH, which can be seen as a variation of photoselective vaporization of the prostate (PVP). This procedure presents several advantages compared to the PVP technique including less laser energy loss, less intraoperative complications as well as more tissue resection rate.

Photoselective Vaporesection of the Prostate with an End-firing Lithium Triborate Crystal Laser

Background:

Photoselective vaporization of the prostate is a technique that is widely used for the treatment of benign prostatic hyperplasia (BPH) and has pronounced advantages compared to the traditional transurethral resection of the prostate. Following the recent introduction of end-firing lithium triborate lasers, we have created a new technique called photoselective vaporesection of the prostate (PVRP). This study described our initial experience using the PVRP technique for the treatment of BPH.

Methods:

This prospective study included a total of 35 patients with BPH who underwent PVRP from August 2013 to July 2014. The chief clinical parameters were obtained and evaluated during the perioperative period and follow-up, including the International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum urinary flow rate, and prostate volume. All variables were evaluated for statistically significant differences compared to baseline values using the analysis of variance.

Results:

The mean subgroup IPSS and QoL scores significantly improved during follow-up; the respective decreases in IPSS storage score, IPSS voiding score, IPSS nocturia score, and QoL score were 75.3%, 83.6%, 51.4%, and 71.7%, respectively (all P < 0.001 compared with baseline). Three patients were diagnosed with prostate cancer based on postoperative pathological examinations. There were no serious perioperative complications.

Conclusion:

The PVRP technique demonstrates satisfactory short-term clinical outcomes and perioperative safety in the treatment of BPH.

Transurethral 160-W straight beam green laser vaporesection of the prostate: initial experience after 180 procedures

Although the photoselective vaporization of the prostate has been considered one of the most promising alternatives for treatment of benign prostatic hyperplasia (BPH), published clinical data with the surgical technology of straight beam lithium triborate laser (LBO) is still lacking. To evaluate the technical improvement and initial experience of the 160-W straight beam LBO laser photoselective vaporesection of the prostate (PVRP) for the surgical treatment of BPH. From September 2012 to September 2014, including a 12-month follow-up, a prospective randomized study was performed. 180 patients undergoing PVRP were included in the study. All patients were preoperatively assessed by International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), post-void residual urine (PVR), prostate-specific antigen level, and prostate volume measurement. Perioperative parameters and complications were recorded. Patients were reassessed at 1, 3, 6 and 12 months postoperatively. PVRP resulted in a significant improvement of IPSS, Qmax, and PVR. Mean operative time was 48.3 ± 14.4 min. A significant improvement for PVRP was achieved regarding the catheter indwelling and hospital stay time. No severe perioperative complications were recorded. No requiring blood transfusion in all patients. Capsule perforation was observed in four patients in the group. There were four patients experienced bladder neck contracture and another four patients were diagnosed urethral stricture, all of whom were treated well by dilatation finally without reoperation. 160-W straight beam LBO laser PVRP appears to be a feasible and safe alternative for symptomatic BPH with decreased length of catheter indwelling and hospital stay time postoperatively.

Photoselective Vaporesection of the Prostate with a Front-firing Lithium Triborate Laser: Surgical Technique and Experience After 215 Procedures

BACKGROUD

Although photoselective vaporization of the prostate (PVP) is considered one of the most promising alternatives to transurethral radical prostatectomy, a longer operative time, an unsatisfactory tissue removal rate, and the absence of postoperative pathology samples remain the main criticisms for this procedure.

OBJECTIVE

To describe the novel technique of photoselective vaporesection of the prostate (PVRP) with a front-firing lithium triborate (LBO) laser and to report our initial experience.

DESIGN, SETTING, AND PARTICIPANTS

This is a prospective study of 215 patients undergoing PVRP between November 2011 and March 2013. Their average age, prostate size, and International Prostate Symptom Score (IPSS) were 70.3 ± 7.3 yr, 70.4 ± 34.0 ml, and 24.9 ± 5.0, respectively.

SURGICAL PROCEDURE

The operative technique is detailed in the accompanying video.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Perioperative data were collected. The patients were followed up at 3, 6, 12 mo after PVRP, and functional outcomes and complications were assessed.

RESULTS AND LIMITATIONS

The mean operation time was 44.1 ± 22.6 min. The mean hemoglobin decrease was 0.37 ± 0.21 g/dl. The catheterization time was 23.9 ± 15.2 h and the postoperative hospital stay was 1.8 ± 0.8 d. Significant improvements were observed in maximum flow, IPSS, and postvoid residual urine at each follow-up time point. Compared to preoperative values, prostate volume and serum prostate-specific antigen fell by 67% and 63%, respectively, at 3 mo after PVRP. No major complications were noted. Application of a hemostat for a front-firing LBO laser makes it easy to handle intractable intraoperative bleeding. The main limitation of this study is the short follow-up period. The influence of PVRP on sexual function and the learning curve remain to be evaluated.

CONCLUSIONS

PVRP is a novel technique that is effective and safe for treatment of benign prostatic hyperplasia. This technique retains the excellent hemostatic property of LBO lasers and has a short operation time and a high tissue removal rate. The problem of the lack of postoperative tissue samples for PVP is also overcome in PVRP.

PATIENT SUMMARY

We have developed a novel technique named photoselective vaporesection of the prostate (PVRP) with a front-firing green laser. Our results show that PVRP retains the excellent hemostatic property of a green laser, but has a much shorter operation time and a higher rate of tissue removal than photoselective vaporization of the prostate (PVP). This technique also solves the problem of the lack of postoperative tissue specimens and the difficulty of handling intractable intraoperative bleeding. According to our initial results, PVRP is a novel technique superior to PVP in the treatment of benign prostatic hyperplasia.