Lithium Triborate Laser Vaporization of the Prostate Using the 120 W, High Performance System Laser: High Performance All the Way?

Laser accessories: surgical fibers, strippers, cleavers, and protective glasses

PURPOSE OF REVIEW

This review provides most recent findings and developments relating to surgical laser fibers, strippers, cleavers, and protective glasses.

RECENT FINDINGS

The smallest core diameter that can be used with Holmium:YAG lasers is 200 μm. Smaller core diameter fibers can be used with the Thulium fiber laser and offer better flexibility and lower risk of fracture, at the risk of greater burnback effect. Misleading discrepancies between the true diameter of laser fibers and their packaging labels must be considered. Fiber tip degradation from the burnback occurs within few minutes, thus questioning the need for time-consuming fiber tip reprocessing with fiber strippers and special cleaving tools. This shortcoming also applies to instrument-protecting ball-tip fibers. Cleavage of fiber tips through their protective jackets ('coated tips') is a cheaper alternative for instrument protection, additionally offering better visual control of the fiber tip. Third-generation side-firing greenlight laser fibers are still prone to rapid deterioration. Laser eyewear does not seem necessary for Holmium:YAG applications, whereas laser-specific protective glasses should be worn for greenlight laser applications.

SUMMARY

With better understanding of laser accessories, practicing urologists may tailor their practice to reach optimal efficacy and safety for Holmium:YAG, Thulium fiber laser and Greenlight laser applications.

GreenLight XPS 180-W Laser Vaporization of Prostate in High-Risk Elderly Patients: A Single-Center Experience

Purpose: To evaluate the safety and efficacy of GreenLight XPS 180-W laser photoselective vaporization of the prostate (PVP) in high-risk elderly patients with benign prostatic hyperplasia. Materials and methods: This retrospective study included 150 elderly patients with enlarged prostate glands (>40 mL) receiving 180-W photoselective vaporization at our department between January 2016 and October 2018. All patients were of advanced age (>80 years) and included those at higher risk of bleeding and cardiopulmonary disease. Perioperative data were collected and analyzed. Results: All operations were completed uneventfully without conversion to open surgery, and nobody died due to postoperative complications. The mean preoperative prostate volume was 65 ± 12.5 mL, mean operative time was 63 ± 12.5 min, mean laser working time was 51 ± 9.2 min, and mean catheterization time was 2.7 ± 1.8 days. There were significant improvements in International Prostate Symptom Scores, quality of life, maximum flow rate, and postvoid residual volume compared with preoperative values. Intraoperative as well as short- and long-term postoperative complication rates were 0.7%, 29.8%, and 13.3%, respectively. Three patients required rehospitalization for postoperative complications, one needed reoperation, and the others recovered after conservative treatment. Conclusions: PVP with a GreenLight XPS 180-W laser in high-risk elderly patients is safe and feasible. It provides a dramatic improvement in both short- and long-term functional outcomes and deserves promotion.

High incidence of urinary tract infections after photoselective laser vaporisation of the prostate: a risk factor analysis of 665 patients

PURPOSE

Although photoselective laser vaporisation of the prostate (PVP) is a recognised alternative to transurethral resection in treating benign prostatic obstruction, there is limited data on the incidence and determinants of postoperative urinary tract infections (UTI). We assessed patients subjected to PVP, evaluating incidence and potential determinants of postoperative UTIs.

MATERIALS AND METHODS

Consecutive patients undergoing PVP between April 2010 and August 2018 were candidates for this retrospective cohort study. The primary outcome measure was microbiologically confirmed postoperative UTI. We fitted uni- and multi-variable Cox models to identify potential risk factors.

RESULTS

Among the 665 included patients, 20% developed postoperative UTIs. The overall incidence rate per 100 patient-days was 0.65 (95% confidence interval [CI] 0.55-0.77). Risk factors for postoperative UTIs were end-stage renal failure (adjusted hazard ratio [aHR] = 14.10, 95% CI 2.08-64.58; p = 0.001) and presence of at least one of the following factors in the 3 months preceding PVP: (i) placement of urinary catheter, (ii) bacteriuria, (iii) UTI, or (iv) antimicrobial treatment (composite aHR = 1.99, 95% CI 1.22-3.24; p < 0.001). There was no apparent association between choice or duration of antimicrobial prophylaxis and incident UTIs.

CONCLUSIONS

Our analysis revealed a high incidence of UTIs after PVP and served to identify certain preoperative risk factors. Neither the choice of antimicrobial regimen nor its duration affected the incidence of UTIs. Prolonged antimicrobials proved to be disproportionately high, warranting further scrutiny in randomised controlled trials.

Role of lasers in urology

Laser technology has long been a standard treatment for many diseases. In particular, laser treatment is considered the standard of care in various urological diseases. While originally primarily restricted to stone treatment, lasers have since evolved to play an important role even in the treatment of malignant diseases. In this review, we take a closer look at the history of lasers in urology and some implications for treatments today.

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.

Prostate volume reduction following pure transurethral bipolar plasma vaporization and conventional transurethral resection of the prostate: a prospective investigation using transrectal 3D ultrasound volumetry

PURPOSE

To evaluate and compare postoperative changes in prostate volume and clinical outcome after bipolar plasma vaporization (BPV) and conventional transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

Consecutive series of patients undergoing BPV or TURP were included in this prospective, nonrandomized study. Planimetric volumetry after transrectal three-dimensional ultrasound of the prostate was performed preoperatively and postoperatively after 6 weeks, 6 months and 12 months. Additionally, changes in clinical outcome parameters were assessed and compared between the groups. The reduction ratio and analysis of covariance were used to compare volume changes between BPV and TURP. Multiple regression analysis was performed to assess a possible interaction between preoperative prostate volume and effect of therapy.

RESULTS

A total of 157 patients were included (BPV: n = 68, TURP: n = 89). Median preoperative prostate volume was 43.1 ml in the BPV group and 45.9 ml in the TURP group (p = 0.43). Postoperatively, the prostate volumes decreased significantly in both groups. After catheter removal, the relative residual prostate volume was significantly higher in the BPV group (66.6 vs. 60.8 %; p = 0.02). Thereafter, significant differences were not detectable anymore (12 months: 46.6 vs. 47.1 %; p = 0.82). Regression analysis revealed that tissue ablation after BPV was superior to TURP in prostates <45 ml but inferior in prostates >45 ml. All clinical outcome parameters improved significantly and were not significantly different between the groups.

CONCLUSIONS

Volume reduction and short-term clinical outcome following pure BPV was excellent and comparable to conventional TURP. However, volume reduction seems to be limited in patients with larger prostates.

A systematic review of experience of 180-W XPS GreenLight laser vaporisation of the prostate in 1640 men

OBJECTIVE

To systematically review the literature regarding clinical outcomes of 180-W XPS GreenLight laser (GL) vaporisation for the treatment of lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH).

METHODS

Recent publications were identified in the field of 180-W GL vaporisation for the treatment of LUTS due to BPH. We searched for peer-reviewed original articles in the English language. Search items were: '180W lithium triborate laser' or '180W greenlight laser' or '180 watt lithium triborate laser' or '180 watt greenlight laser' or 'XPS greenlight laser'. In all, 30 papers published between 2012 and 2014 matched this search. Of these, 10 papers were identified dealing with consecutive cohorts of patients treated with the 180-W XPS GL RESULTS: The 10 papers included a total experience of 1640 patients. The only randomised controlled trial in this field compares 180-W with transurethral resection of the prostate (TURP). Functional outcomes and prostate volume reduction after GL vaporisation were similar to TURP. Catheterisation time and hospital stay were shorter in patients undergoing 180W XPS GL vaporisation (41 and 66 h vs 60 and 97 h, respectively). Four papers compared the 180-W XPS system to former GL devices showing increased operation time efficiency and comparable postoperative voiding results and adverse events. One paper defined the learning curve to achieve an expert level according to the speed of the procedure and the effectiveness of volume reduction was met after 120 procedures.

CONCLUSION

The 180-W XPS GL offers shorter operation times than former devices. In the one randomised controlled trial comparison with TURP, volume reduction and functional results were comparable to those of TURP. Longer term studies are required.

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.

Absorption of irrigation fluid occurs frequently during high power 532 nm laser vaporization of the prostate

PURPOSE

Absorption of irrigation fluid was not detected during GreenLight™ laser vaporization of the prostate using the first generation 80 W laser. However, data are lacking on intraoperative irrigation fluid absorption using the second generation 120 W high power laser. We assessed whether fluid absorption occurs during high power laser vaporization of the prostate.

MATERIALS AND METHODS

We performed this prospective investigation at a tertiary referral center in patients undergoing 120 W laser vaporization for prostatic bladder outlet obstruction. Normal saline containing 1% ethanol was used for intraoperative irrigation. The expired breath ethanol concentration was measured periodically during the operation using an alcometer. The volume of saline absorption was calculated from these concentrations. Intraoperative changes in hematological and biochemical blood parameters were also recorded.

RESULTS

Of 50 investigated patients 22 (44%) had a positive breath ethanol test. Median absorption volume in the absorber group was 725 ml (range 138 to 3,452). Ten patients absorbed more than 1,000 ml. Absorbers had a smaller prostate, more capsular perforation, higher bleeding intensity and more laser energy applied during the operation. Three patients (13%) had symptoms potentially related to fluid absorption. Hemoglobin, hematocrit and serum chloride were the only blood parameters that changed significantly in the absorber group. The changes were significantly different than those in nonabsorbers.

CONCLUSIONS

Fluid absorption occurs frequently during high power laser vaporization of the prostate. This should be considered in patients who present with cardiopulmonary or neurological symptoms during or after the procedure.

Optical feedback-induced light modulation for fiber-based laser ablation

Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.

Ablative efficiency of 532-nm laser vaporization compared to transurethral resection of the prostate: results from a prospective three-dimensional ultrasound volumetry study

PURPOSE

To assess and compare postoperative prostate volume changes following 532-nm laser vaporization (LV) and transurethral resection of the prostate (TURP). To investigate whether differences in volume reduction are associated with differences in clinical outcome.

METHODS

In this prospective, non-randomized study, 184 consecutive patients undergoing 120 W LV (n = 98) or TURP (n = 86) were included. Transrectal three-dimensional ultrasound and planimetric volumetry of the prostate were performed preoperatively, after catheter removal, 6 weeks, 6 and 12 months. Additionally, clinical outcome parameters were recorded. Mann-Whitney U test and analysis of covariance were utilized for statistical analysis.

RESULTS

Postoperatively, a significant prostate volume reduction was detectable in both groups. However, the relative volume reduction was lower following LV (18.4 vs. 34.7 %, p < 0.001). After 6 weeks, prostate volumes continued to decrease in both groups, yet differences between the groups were less pronounced. Nonetheless, the relative volume reduction remained significantly lower following LV (12 months 43.3 vs. 50.3 %, p < 0.001). All clinical outcome parameters improved significantly in both groups. However, the maximum flow rate (Q max) and prostate-specific antigen (PSA) reduction were significantly lower following LV. Subgroup analyses revealed significant differences only if the initial prostate volume was >40 ml. Re-operations were necessary in three patients following LV.

CONCLUSIONS

The modest but significantly lower volume reduction following LV was associated with a lower PSA reduction, a lower Q max and more re-operations. Given the lack of long-term results after LV, our results are helpful for preoperative patient counseling. Patients with large prostates and no clear indication for the laser might not benefit from the procedure.

Investigation on safety aspects of forward light propagation during laser surgery

During laser treatment of prostate, urological surgeons occasionally experience fiber-cap failure due to concentration of thermal stress on the fiber tip. Upon the cap breakage, laser light becomes forward-propagating and may adversely affect the bladder tissue such as perforation. The purpose of the current study was to identify any bladder perforation with forward-propagating laser light (λ = 532 nm) at 80 and 120 W with an assumption of fiber-cap failure. Perforation time was measured and compared in terms of fiber distance. The results showed that 80 and 120 W perforated the tissue up to 2 and 2.5 cm, respectively with perforation threshold of 17.2 kW/cm(2), and the minimum perforation time was approximately 7 s. No perforation occurred at the distance of 3 cm for 1-min irradiation at both power levels, but severely carbonized lesions were generated around the irradiated tissue. Although equivalent ablation speed was found between the two power levels, 120 W created up to 20 % wider craters regardless of fiber distance. With consideration of dense collagen fibers in bladder structure and long surgical distance, direct incidence of laser perforation on bladder wall could be unlikely to happen upon fiber-cap failure during laser surgery.

The effect of increased maximum power output on perioperative and early postoperative outcome in photoselective vaporization of the prostate

BACKGROUND AND OBJECTIVE

Preclinical studies suggest an increased vaporization rate and speed of the 532 nm 180-W XPS GreenLight laser (180-W) compared with the 120-W HPS GreenLight laser (120-W) and the 80-W PV GreenLight laser (80-W). To test the clinical relevance of this observation we analyzed intraoperative data and early postoperative results after photoselective vaporization of the prostate (PVP) with the 180-W, 120-W, and 80-W laser.

STUDY DESIGN/MATERIALS AND METHODS

A retrospective pair-to-pair comparison was performed including 80 consecutive patients who underwent PVP for the treatment of benign prostate enlargement with the 180-W, 120-W, and 80-W laser. The groups matched concerning age, prostate volume, PSA-value, and preoperative catheterization. Primary study outcome measurement was PSA-value reduction at 3 months; intraoperative data, perioperative complications, and early postoperative functional course were secondary study outcome measurements.

RESULTS

Energy application per case (kJ), preoperative prostate volume (kJ/ml) operating time (kJ/minute), and lasing time (kJ/minute) was significantly higher with the 180-W laser. Prevalence of impaired visibility due to bleeding was comparable between the 180-W and the 120-W laser but significantly lower with 80-W. Duration of hospitalization was shorter with the 180-W laser compared to the former laser systems. During the postoperative course of 3 months voiding parameters and micturition symptoms significantly improved in all groups, the incidence of postoperative dysuria was comparable. Postoperative PSA-value reduction was significantly higher after treatment with the 180-W laser.

CONCLUSIONS

With the 180-W laser, higher energy application and higher speed of tissue vaporization leads to increased tissue vaporization compared to the former 120-W and 80-W laser systems. Clinical efficacy and perioperative safety are maintained with the higher powered laser.