Lithium Triborate Research Articles

Photoselective vaporization of the prostate using GreenLight 120-W lithium triborate laser to treat symptomatic benign prostatic hyperplasia: A single-centre prospective study

We evaluated the safety and efficacy of photoselective vaporization of the prostate (PVP) using GreenLight 120-W lithium triborate (LBO) laser to treat symptomatic small-to-medium sized benign prostatic hyperplasia (BPH). This prospective non-controlled observational study included symptomatic BPH men ≥50 years with international prostate symptom score (IPSS) ≥14, prostate volume (PV) ≤80 cc and maximum flow rate (Q-max) ≤15 mL/s. PVP was performed using the GreenLight 120-W LBO laser machine. Patients were assessed at baseline and postoperatively at discharge, 2 weeks, and 3, 6 and 12 months. We measured changes in IPSS, PV, PSA, Q-max, post-void residual (PVR), hemoglobin (Hb), serum sodium (Na+) and reported complications. Statistical significance was p < 0.05. The study included 103 men with mean age of 67 (±standard deviation)±9.7 years. Thirty patients were on indwelling urethral catheters for refractory urinary retention and 12 on ongoing anticoagulants. The mean baseline IPSS, PV, PSA, Q-max and PVR parameters significantly improved at follow-up (p < 0.001; each). Mean measurements at baseline versus at six months were: IPSS 25.6 ± 4.2 vs. 7.4±2.3; PV 44.6 ± 9.2 vs. 21.6 ± 6.3 cc (51.6% reduction); Q-max 5.8 ± 3.4 vs. 20.4 ± 4.8 mL/s; PVR 110 ± 40 vs. 35 ± 9 cc. Mean baseline Hb and serum Na+ declined non-significantly (p > 0.05) at discharge and at 2 weeks. No patient needed a blood transfusion. Secondary procedures were needed in 2 patients for urethral and bladder neck strictures. The re-treatment rate for residual adenoma was 0.97%. PVP using the GreenLight 120-W LBO laser to treat small-to-medium sized symptomatic BPH demonstrated significant improvements in efficacy parameters and high safety profile within 12 months of follow-up. The procedure entails good hemostasis with minimal blood loss even in patients receiving ongoing anticoagulants.

GREENLIGHT HPS™ 120‐W LASER VAPORIZATION VS TRANSURETHRAL RESECTION OF THE PROSTATE (&lt;60 ML): A 2‐YEAR RANDOMIZED DOUBLE‐BLIND PROSPECTIVE URODYNAMIC INVESTIGATION

The major point of concern relates to the retrospective power analysis and extremely low patient numbers. With only 10 patients per arm, the study power was subsequently calculated by the authors to average ≈ 26%. In our calculations, this mean power is in keeping with an effect size (theta) of 1.0. Using the generally accepted study power of 80%, 50 patients are required per arm if we are to keep the same 99% confi dence; if the effect size is indeed lower, say 0.5, then 95 patients per arm would be required. The papers ’ conclusions are thus unfortunately unable to be supported by the data presented. Further concerns arise from incongruence between IPSS results as described in the body and those present in Table 2. Lastly, the Greenlight HPS laser used in the study is repeatedly described as potassium-titanyl-phosphate (KTP), the HPS uses lithium triborate and not KTP. Nevertheless, this paper presents an interesting point regarding preand postoperative urodynamic studies, and could serve as a pilot for future work.

2178 EARLY EXPERIENCE PHOTOSELECTIVE VAPORISATION OF THE PROSTATE USING THE 180W LITHIUM TRIBORATE AND COMPARISON WITH THE 120W LITHIUM TRIBORATE LASER

You have accessJournal of UrologyBenign Prostatic Hyperplasia: Surgical Therapy and New Technology III1 Apr 20122178 EARLY EXPERIENCE PHOTOSELECTIVE VAPORISATION OF THE PROSTATE USING THE 180W LITHIUM TRIBORATE AND COMPARISON WITH THE 120W LITHIUM TRIBORATE LASER Nicholas Campbell, Amanda Chung, Peter Yoon, Isaac Thangasamy, and Henry Woo Nicholas CampbellNicholas Campbell Sydney, Australia More articles by this author , Amanda ChungAmanda Chung Sydney, Australia More articles by this author , Peter YoonPeter Yoon Sydney, Australia More articles by this author , Isaac ThangasamyIsaac Thangasamy Sydney, Australia More articles by this author , and Henry WooHenry Woo Sydney, Australia More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2351AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES There is little information on the clinical efficacy and safety of the photoselective vaporization (PVP) of the prostate using the new highly powerful 180W lithium triborate (LBO) laser. The objective of this study was to report on initial outcomes of PVP with the 180W laser with the first 50 cases and to compare it the last 50 cases performed with the 120W LBO laser. METHODS A registry of all PVP cases performed by a single surgeon (HHW) has been prospectively maintained. The last 50 cases treated with the 120W LBO laser (December 2009 to August 2010) were compared with the first 50 cases treated with the 180W LBO (July 2010 and June 2011). The inclusion criteria were all men undergoing PVP for indications consistent with established guidelines for surgery for benign prostatic hyperplasia. Baseline patient variables for men treated with the 120W and 180W LBO laser were recorded preoperatively and compared to postoperative parameters at 3 months and perioperative data was also recorded. RESULTS The 180W cases had a larger mean TRUS prostate volume (80.5cc versus 59.4cc, p<0.05). For the 180W and 120W LBO lasers, total operating time was 64.2 and 72.5 minutes (NS, p=0.22), lasering time 49.6 and 69.3 minutes (NS, p=0.30) and energy utilisation 477.6kJ and 377.9kJ (p<0.05) respectively. Complications did not significantly differ between the two lasers. Using the Clavien-Dindo classification there were 5 grade 1 complications and 3 grade 3b (bladder neck contractures) with the 180W LBO laser and with the 120 W LBO laser there were 4 grade 1 complications and 1 grade 2. CONCLUSIONS This study demonstrates that there is little change in clinical outcomes with the transition from 120W to 180W LBO PVP with an already experienced PVP surgeon. The introduction of the more powerful 180W LBO laser appears to have impacted upon patient selection with significantly increased prostate size and associated with increased energy utilisation. There appears to be a trend toward shorter laser times. Comparison of 180W versus 120W LBO Laser Perioperative Parameters 180W baseline 180W 3 month 120W baseline 120W 3 month IPSS 21 10 27 9 QL 4 2 4 2 Qmax (ml/s) 9 29 9 26 PVR (ml) 227 55 168 51 © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e878 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nicholas Campbell Sydney, Australia More articles by this author Amanda Chung Sydney, Australia More articles by this author Peter Yoon Sydney, Australia More articles by this author Isaac Thangasamy Sydney, Australia More articles by this author Henry Woo Sydney, Australia More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Photoselective vaporization of the prostate using the 180W lithium triborate laser

Photoselective vaporization of the prostate (PVP) is widely used to treat benign prostatic obstruction (BPO), but there is little experience reported on the new more powerful 180W lithium triborate (LBO) laser. This study evaluates the safety and efficacy of using the 180W LBO laser to treat BPO by examining a multicentre Australian experience. Retrospective review of prospectively collected data on all men treated by 180W LBO laser PVP by eight urologists across six Australian hospitals, from July 2011 to August 2011, was performed. Perioperative and functional outcomes were examined at baseline and 3 months. Of the 85 men (median age 70 years, prostate volume 51 cm(3)) identified, 27% (23/85) were in urinary retention and 44% (37/85) were taking antiplatelet/anticoagulant medication. Median operating time was 46 min, laser time 27 min, energy use 211 kJ, post-operative duration of catheterization 15 h and hospitalization 22 h. Functional outcomes from baseline to 3 months, respectively, were for IPSS 25-7; QoL 5-2; Qmax 7.7-18.4; and PVR 147-38. All improvements were statistically significant (P < 0.01). Thirty-eight percent (32/85) of patients experienced at least one adverse event. Most adverse events were low Clavien-Dindo grade I-II. There were five grade III, two grade IV and no grade V adverse events. Sixty per cent (51/85) of men were able to be discharged home voiding successfully without a catheter within 24-h post-PVP. Our early multicentre Australian experience indicates the 180W LBO laser PVP is an efficacious and safe treatment for BPO.

Intracavity second-harmonic generation at 320 nm of an actively Q-switched Pr:LiYF4 laser

We demonstrate pulse laser operation of a Pr:LiYF(4) laser pumped by InGaN laser diodes (444 nm) using an acousto-optic modulator. We obtained a maximum laser peak power of 167 W (4 μJ/pulse) with a pulse width of 24 ns at an 11 kHz repetition rate for a 63 nm wavelength. Employing an 8 mm long lithium triborate nonlinear crystal in the laser cavity, we obtained a maximum peak power of 55 W (2.7 μJ/pulse) at 320 nm, which corresponds to a conversion efficiency of 69% with respect to the fundamental laser energy. The UV laser pulse width was 36 ns.

High-power, high repetition-rate, green-pumped, picosecond LBO optical parametric oscillator

We report on a picosecond, green-pumped, lithium triborate optical parametric oscillator with record-high output power. It was synchronously pumped by a frequency-doubled (530 nm), pulse-compressed (4.4 ps), high-repetition-rate (230 MHz), fiber-amplified gain-switched laser diode. For a pump power of 17 W, a maximum signal and idler power of 3.7 W and 1.8 W was obtained from the optical parametric oscillator. A signal pulse duration of ~3.2 ps was measured and wide tunability from 651 nm to 1040 nm for the signal and from 1081 nm to 2851 nm for the idler was achieved.

Mini-Photoselective Vaporization of the Prostate for Difficult Intermittent Self-Catheterization

Bladder neck incision or transurethral incision of the prostate is a procedure described for men with bladder outflow obstruction associated with a gland size of less than 30 ml. We report a case of a man with detrusor dysfunction who was having increasing difficulty performing clean intermittent self-catheterization of the bladder. The successful use of the 120 W lithium triborate laser to perform a "mini-photoselective vaporization of the prostate" ("mini-PVP") enabled discharge of the patient on the same day as well as resolution of the patient's difficulties in performing self-catheterization. Mini-PVP has proven to be a simple and effective approach to resolution of a prostate configuration impeding the process of clean intermittent self-catheterization.

High peak power green light generation using ytterbium fiber amplifier and lithium triborate crystal

We reported on a master-oscillator fiber power amplifier (MOPA) system and a second-harmonic generation (SHG) system. Actively Q-switched Nd:YVO4 laser was used as a seed source of light pluses. The MOPA system produced as much as 76 kW of peak power at wavelength of 1064 nm, with 35 kHz repetition rate and 20 ns pulse duration. With a lithium triborate (LBO) crystal at type II phase matching, a maximum 16 kW of peak power had been demonstrated. The fiber nonlinear effects such as stimulate Brillouin scattering (SBS) and stimulate Raman scattering (SRS) and the SHG conversion efficiency were investigated.

Optical, mechanical and laser-induced damage threshold properties of 1 064 nm, 532 nm frequency-doubled antireflection coating for LBO

1 064 nm, 532 nm frequency-doubled antireflection (AR) coatings with buffer layer of SiO2 between the coating and the substrate were fabricated by the electron beam evaporation technology on the substrate of lithium triborate (LiB3O5 or LBO) crystals. The residual reflectance of the sample is 0.07% and 0.11% at 1 064 nm and 532 nm, respectively. The adhesion and the laser-induced damage threshold (LIDT) of the sample are greater than 200 mN and 18.6 J/cm2. The strengthening mechanism of adhesion and LIDT of the buffer layer of SiO2 were discussed by considering full plastic indentation and shear theory, and spallation of a plated film induced by thermal shock stress, respectively.

Sexual function outcome following photoselective vaporisation of the prostate

There is little reported on sexual functional outcome following photoselective vaporisation of the prostate using the 120 W lithium triborate laser. The objective of this study was to evaluate changes in sexual function at 3 and 12 months following PVP. The primary outcome measures were changes in voiding parameters and changes in erectile function in the international index of erectile function (IIEF-5). Change in erectile function was defined as mild (<5 IIEF points) or major (≥5 points). Results found that 75% of men had an IIEF-5 < 17 at baseline. At 3 months, the mean post-operative IIEF-5 score was unchanged compared to baseline (P = 0.13). A major decline in erectile function was seen in 12.4 and 24% of men at 3 and 12 months, respectively, and a major improvement in erectile function was seen in 8.3 and 6% at 3 and 12 months, respectively. There was no correlation in change in erectile function with urinary function, quality of life and loss of emission on orgasm. Loss of emission on orgasm was reported in 65% of respondents. Significant changes in erectile function are observed following PVP although a cause and effect relationship remains unclear.

Parametric Kerr lens mode-locked, 888 nm pumped Nd:YVO_4 laser

Self-starting cw mode locking of a 888 nm pumped high-power Nd:YVO(4) laser using the χ(2):χ(2) cascaded Kerr lens in lithium triborate without exploiting the "nonlinear mirror" technique is presented. The nonlinear loss modulations are mainly provided by a soft aperture mechanism in the gain medium. A high average output power up to 15.4 W at 10.8 ps pulse duration and short pulses down to 5.7 ps at 11.4 W have been achieved.

Editorial Comment

Bleeding, intraoperative or postoperative, is one of the biggest ways to ruin a urologist's day. So, to think of operating on a man's prostate when he is actively taking coumadin “is ridiculous.” That answer would have been the most common response from most of our speciality doctors just a few years ago. This article reproduces results that vaporization of the prostate, now with 120 W lithium Triborate Laser, can be performed safely on patients actively taking coumadin. While this is not my standard care practice, I find it reassuring that in the situation that a man is unable to discontinue his coumadin; this procedure remains a safe option. My standard care practice is to discontinue anticoagulants, such as coumadin, 5 days before prostate laser vaporization, if medically cleared to do so. However, if the patient must remain anticoagulated, I discuss the increased potential bleeding risks of a surgical procedure while on coumadin, and only then, perform the surgery. Photoselective Vaporization of the Prostate with the 120-W Lithium Triborate Laser in Men Taking CoumadinUrologyVol. 78Issue 1PreviewTo specifically evaluate perioperative morbidity associated with men who were taking coumadin and continued on this medication at therapeutic levels for the purposes of the prostate (PVP). Increasing numbers of men are taking coumadin for medical comorbidity and this creates clinical concerns for urologists treating such men with benign prostatic obstruction. Photoselective vaporization of the PVP has been shown to be an effective treatment for men receiving anticoagulation treatment, although previously published studies have evaluated a mix of men on aspirin, coumadin, or clopidogrel. Full-Text PDF ReplyUrologyVol. 78Issue 1PreviewThe ability to treat men with photoselective vaporization of the prostate while on Coumadin makes a great deal sense. We understand well the physics of the laser tissue interaction whereby the 532-nm wavelength is absorbed by human tissue with such efficiency to effect vaporization and to then create beyond this an effective thin layer of coagulation. Our reported experience comes off the back of experience with the 80-W KTP laser, which was the predecessor to the 120-W LBO laser. We became “comfortable” with the ability to perform PVP with the 80-W KTP laser and became convinced that we could not tell whether a man was on Coumadin or not on the basis of intraoperative surgical appearances. Full-Text PDF

Synthesis and thermoluminescence properties of rare earth oxides (Y, Ce-Lu) doped lithium triborate

Lithium triborate (LiB 3O 5) was synthesized by high temperature solid-state reaction method, and then rare earth oxides were doped into LiB 3O 5 to enhance its thermoluminescent (TL) properties. The identification and characteristics of the obtained compounds were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analyses, differential thermal analyses (DTA) and scanning electron microscopy (SEM). The glow curves were obtained using a thermoluminescent (TL) reader. The results revealed that all the rare earth oxides were not good activators for lithium triborate and the obtained compounds could not be used for dosimetric applications.

Spectral phase retrieval of 8 fs optical pulses at 600 nmby using a collinear autocorrelator with 300-μm-thick lithium triborate crystals

We report on noniterative spectral phase retrieval of 1.1 nJ, 8 fs pulses at 600 nm by using 300-μm-thick lithium triborate crystals in a standard collinear autocorrelator with ≈2 min data acquisition time. This method is simple, sensitive, and immune to the spectral distortion and UV absorption of the linear and nonlinear optics.

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

Technical modifications of the 120 W lithium-triborate laser have been implemented to increase power output, and prevent laser fiber degradation and loss of power output during laser vaporization of the prostate. However, visible alterations at the fiber tip and the subjective impression of decreasing ablative effectiveness during lithium-triborate laser vaporization indicate that delivering constantly high laser power remains a relevant problem. Thus, we evaluated the extent of laser fiber degradation and loss of power output during 120 W lithium-triborate laser vaporization of the prostate. We investigated 46 laser fibers during routine 120 W lithium-triborate laser vaporization in 35 patients with prostatic bladder outflow obstruction. Laser beam power was measured at baseline and after the application of each 25 kJ during laser vaporization. Fiber tips were microscopically examined after the procedure. Mild to moderate degradation at the emission window occurred in all fibers, associated with a loss of power output. A steep decrease to a median power output of 57.3% of baseline was detected after applying the first 25 kJ. Median power output at the end of the defined 275 kJ lifespan of the fibers was 48.8%. Despite technical refinements of the 120 W lithium-triborate laser fiber degradation and significantly decreased power output are still detectable during the procedure. Laser fibers are not fully appropriate for the high power delivery of the new system. There is still potential for further improvement in the laser performance.

Photoselective Vaporization of the Prostate with the 120-W Lithium Triborate Laser in Men Taking Coumadin

To specifically evaluate perioperative morbidity associated with men who were taking coumadin and continued on this medication at therapeutic levels for the purposes of the prostate (PVP). Increasing numbers of men are taking coumadin for medical comorbidity and this creates clinical concerns for urologists treating such men with benign prostatic obstruction. Photoselective vaporization of the PVP has been shown to be an effective treatment for men receiving anticoagulation treatment, although previously published studies have evaluated a mix of men on aspirin, coumadin, or clopidogrel. From a prospective database of men treated with the 120-W lithium triborate (LBO) laser from November 2006 to July 2010, 43 men were identified to have been on coumadin during their PVP. The mean age was 73.4 years (range, 55-90) and mean prostate size was 75.3 mL (range, 20-227). Perioperative morbidity and early functional outcomes were examined. No men required a blood transfusion, although 2 of 43 (4.7%) men had prolonged catheterization for bleeding. No patient required discontinuation of the coumadin during the perioperative period. Urinary tract infection occurred in 4 (9.3%) and recatheterization in 6 (14%). Apart from 3 outliers, the mean postoperative length of stay was 21.6 hours. At 3 months, improvements in International Prostate Symptom Score, peak urinary flow rate, and postvoid residual were similar to previously reported series of men not taking an anticoagulant. PVP in this high-risk group of patients has low perioperative morbidity and is associated with good early functional outcomes.

Femtosecond OPO based on LBO pumped by a frequency-doubled Yb-fiber laser-amplifier system for CARS spectroscopy

We present detailed investigations of a femtosecond green-pumped optical parametric oscillator (OPO) based on lithium triborate. As pump source, a frequency-doubled Yb-fiber laser-amplifier system is used. The OPO generates signal pulses tunable over a spectral range from 780 to 940 nm and idler pulses tunable from 1630 to 1190 nm. More than 250 mW are generated in the signal beam and more than 300 mW in the idler beam. Without dispersion compensation chirped signal pulses with a pulse duration between 100 and 250 fs are measured. Using this system for coherent anti-Stokes Raman scattering spectroscopy, vibrational resonances between 1110 and 6760 cm−1 can be excited. Due to the chirped pulses, a spectral resolution of 100 cm−1 is achieved, which is 2.5 times higher compared to an excitation with time-bandwidth limited pulses.

Photoselective vaporization for prostatic obstruction with the 120‐W lithium triborate laser: 1‐year clinical outcomes

There are few reports of the clinical outcomes of photoselective vaporization of the prostate (PVP) for benign prostatic hyperplasia (BPH) using the 120-W lithium triborate (LBO) laser. The present study evaluates clinical outcomes of 76 men treated with the 120-W LBO laser by an experienced PVP surgeon with 12 months follow up. The International Prostate Symptom Score (IPSS), peak flow rate (Qmax) and post-void residual (PVR) were examined at baseline and at 3 and 12 months. These parameters at baseline and 12 months were 20 ± 7.0, 7.6 ± 3.5 mL/s, 155 ± 155 mL and 8.1 ± 6.1, 22.5 ± 10.3 mL/s, 59 ± 87 mL, respectively. Clinically, meaningful improvements in IPSS, Qmax and PVR were observed at 3 months and sustained at 12 months. There were few adverse events, with only 5.3% of patients requiring recatheterization. Clinical outcome at 12 months was similar to that at 3 months and to other published series.

Greenlight: from potassium-titanyl-phosphate to lithium triborate or from good to better?

To report on the latest data in the recent literature regarding the so-called 'Greenlight laser vaporization of the prostate'. Specifically to comment on the evolution of the 80-W KTP (potassium-titanyl-phosphate) system to the more recent 120-W LBO (lithium triborate) system. In general, in spite of the broad clinical acceptance of this innovative technique, high-quality studies on the more recent 120-W LBO device are scarce. However, one randomized mid-term trial comparing the 120-W LBO version with conventional transurethral resection of the prostate has very currently been published. Moreover, experimental data on the updated system are now available. Even though no direct comparison of the 80-W KTP and the 120-W LBO system is accessible, the very recent data promise a further enhancement of Greenlight laser vaporization. This especially applies to improved tissue ablation leading to shorter operation times. However, time is not standing still, as we await data on the 180-W LBO system, which has just been launched. Hopefully, we can expect sound clinical and experimental data in the very near future.

Towards homonuclear J solid-state NMR correlation experiments for half-integer quadrupolar nuclei: experimental and simulated 11B MAS spin-echo dephasing and calculated 2JBB coupling constants for lithium diborate

Magic-angle spinning (MAS) NMR spin-echo dephasing is systematically investigated for the spin I = 3/2 (11)B nucleus in lithium diborate, Li(2)O·2B(2)O(3). A clear dependence on the quadrupolar frequency (ω(Q)(PAS)/2π = 3C(Q)/[4I(2I- 1)]) is observed: the B3 (larger C(Q)) site dephases more slowly than the B4 site at all investigated MAS frequencies (5 to 20 kHz) at 14.1 T. Increasing the MAS frequency leads to markedly slower dephasing for the B3 site, while there is a much less evident effect for the B4 site. Considering samples at 5, 25, 80 (natural abundance) and 100% (11)B isotopic abundance, dephasing becomes faster for both sites as the (11)B isotopic abundance increases. The experimental behaviour is rationalised using density matrix simulations for two and three dipolar-coupled (11)B nuclei. The experimentally observed slower dephasing for the larger C(Q) (B3) site is reproduced in all simulations and is explained by the reintroduction of the dipolar coupling by the so-called "spontaneous quadrupolar-driven recoupling mechanism" having a different dependence on the MAS frequency for different quadrupolar frequencies. Specifically, isolated spin-pair simulations show that the spontaneous quadrupolar-driven recoupling mechanism is most efficient when the quadrupolar frequency is equal to twice the MAS frequency. While for isolated spin-pair simulations, increasing the MAS frequency leads to faster dephasing, agreement with experiment is observed for three-spin simulations which additionally include the homogeneous nature of the homonuclear dipolar coupling network. First-principles calculations, using the GIPAW approach, of the (2)J(11B-11B) couplings in lithium diborate, metaborate and triborate are presented: a clear trend is revealed whereby the (2)J(11B-11B) couplings increase with increasing B-O-B bond angle and B-B distance. However, the calculated (2)J(11B-11B) couplings are small (0.95, 1.20 and 2.65 Hz in lithium diborate), thus explaining why no zero crossing due to J modulation is observed experimentally, even for the sample at 25% (11)B where significant spin-echo intensity remains out to durations of ∼200 ms.