An energy efficiency assessment of Yttrium-aluminum-garnet laser in vitro.

To study the effect range of the Nd:YAG laser through various levels of cloudy medium for targets with varying grayscale values in vitro. The coated paper cards with grayscale values of 0, 50, 100, and 150 were used as the laser's targets, which were struck straightly with varying energies using three burst modes (single pulse, double pulse, and triple pulse). Six filters (transmittances of 40, 50, 60, 70, 80, and 90) were applied to simulate various levels of cloudy refractive medium. Image J software was used to measure the diameters and regions of the laser spots. The ranges of the Nd:YAG laser spots increased with energy in the same burst mode (P < 0.05). Under the same amount of energy, the ranges of the Nd:YAG laser spot increased with the grayscale value of the targets (P < 0.05). The greater the transmittance of the filters employed, the larger the range of the Nd: YAG laser spots produced. Assuming that the total pulse energy is identical, the effect ranges of multi-pulse burst modes were significantly larger than those of single-pulse burst mode (P < 0.05). The effect range of a Nd:YAG laser grows with increasing energy and the target's grayscale value. A cloudy refractive medium has a negative impact on the effect range of the Nd: YAG laser. The single pulse mode has the narrowest and safest efficiency range.

Root surface roughness evaluation following application of different periodontal instruments and Er:YAG laser: A profilometry and SEM study.

AIM: The aim of the present study was to evaluate the efficacy of 30°-angled Er:YAG laser tip and different periodontal instruments on root surface roughness and morphology in vitro. METHODS: Eighteen bovine teeth root without carious lesion were decoronated from the cementoenamel junction and seperated longitidunally. A total of 36 obtained blocks were mounted in resin blocks and polished with silicon carbide papers under water irrigation. These blocks were randomly assigned into 3 treatment groups. In Group 1, 30°-angled Er:YAG laser (2.94 µm) tip was applied onto the blocks with a 20 Hz, 120 mJ energy output under water irrigation for 20 s. In Groups 2 and 3, the same treatment was applied to the blocks with new generation ultrasonic tip and conventional curette apico-coronally for 20 s with a sweeping motion. Surface roughness and morphology were evaluated before and after instrumentation with a profilometer and SEM, respectively. RESULTS: After instrumentation, profilometric analysis revealed significantly higher roughness values compared to baseline in all treatment groups(p < 0.05). Laser group revealed the roughest surface morphology followed by conventional curette and new generation ultrasonic tip treatment groups (p < 0.05). In SEM analysis, irregular surfaces and crater defects were seen more frequently in the laser group. CONCLUSION: Results of the study showed that the use of new generation ultrasonic tip was associated with smoother surface morphology compared to 30°-angled Er-YAG laser tip and conventional curette. Further in vitro and in vivo studies with an increased sample size are necessary to support the present study findings.

A comparison between vapor tunnel and virtual basket for the treatment of proximal ureteral stones using holmium:YAG laser (Cyber Ho): which is the best tool to reduce retropulsion?

PURPOSE: To compare vapor tunnel (VT) and virtual basket (VB) tools to reduce retropulsion in the treatment of proximal ureteral stones. METHODS: Patients with a single proximal ureteral stone were randomly assigned to holmium laser lithotripsy with the use of VT (Group A) or VB (Group B) tool. The 150W holmium:YAG cyber Ho generator was used. We compared operative time, dusting time, need for flexible ureteroscopy due to stone push-up and occurrence of ureteral lesions. The stone-free rate (SFR) and the occurrence of postoperative ureteral strictures were assessed. RESULTS: 186 patients were treated, of which 92 with the VT (49.5%, Group A) and 94 with the VB (50.5%, Group B). Mean stone size was 0.92 vs. 0.91 cm in Groups A vs. B (p = 0.32). Mean total operative time and dusting time were comparable between groups. 7 (7.6%) vs. 6 (6.4%) patients in Groups A vs. B required a flexible ureteroscope because of stone push-up (p = 0.12). Ureteral mucosa lesions were observed in 15 (16.3%) vs. 18 (19.1%) cases in the VT vs. VB group (p = 0.09). 1-Month SFR was comparable (97.8% vs. 95.7%, p = 0.41). We observed one case (1.1%) of postoperative ureteral stricture in the VT group vs. two cases (2.1%) in the VB group (p = 0.19). CONCLUSIONS: VT and VB are equally safe and effective tools in reducing retropulsion of ureteral stones. Operative time, dusting time and SFR were comparable. They also equally avoided stone push-up and prevented ureteral lesions, which may later occur in ureteral strictures.

How I Do It: Teaching holmium laser enucleation of the prostate (HoLEP).

Holmium laser enucleation of the prostate (HoLEP) is considered a size-independent technique to treat benign prostatic hyperplasia. This safe and effective procedure is increasingly being adopted in urology training programs worldwide, yet limited teaching strategies have been described. Endoscopic handling during HoLEP allows for a simultaneous interaction between the surgeon and trainee, facilitating a guided teaching strategy with increasing difficulty as experience grows. In this article, we describe our stepwise approach for teaching HoLEP as part of a structured surgical training curriculum. We also evaluate the association of our method with intraoperative efficiency parameters and immediate postoperative surgical outcomes of 200 HoLEP procedures.

Holmium laser enucleation of the prostate for a case of transition zone prostate cancer.

Standard treatment approaches for localized prostate cancer remain limited to active surveillance, radiotherapy, and radical prostatectomy. We present a case of transition zone prostate cancer that was treated with holmium laser enucleation of the prostate, a procedure that is normally reserved for the management of benign prostatic hyperplasia.

Evaluation of the learning curve for Thulium laser enucleation of the prostate in a contemporary cohort.

PURPOSE: To assess the learning curve of Thulium laser enucleation of the prostate (ThuLEP) of a single surgeon. METHODS: Hundred patients suffering from benign prostatic hyperplasia were treated by the same surgeon. In all cases, a well-trained urologist was present in the operating room. Patients urinary function was assessed preoperatively using the International Prostate Symptoms Score (IPSS), maximum flow rate and Post-Void Residual volume. Preoperative prostate volume was recorded. Enucleation and morcellation efficiency and complication rate were evaluated. Patients were divided into 5 cohorts of 20 consecutive cases to assess changes in outcomes through time. RESULTS: Mean age of patients was 73.1 years (SD 17.5) and mean prostate volume was 89.7 ml (SD 55.1). Overall, mean enucleation and morcellation efficiency were 1.7 (SD 2.9) and 5.1 (SD 2.7) g/min. A statistically significant increase in enucleation efficiency was observed when comparing cohort 1 vs 2 (0.9 vs 1.3 g/min, p = 0.03) and cohort 2 vs 3 (1.3 vs 1.7 g/min, p = 0.02). A statistically significant increase in morcellation efficiency was observed when comparing cohort 1 vs 2 (2.8 vs 3.7 g/min, p = 0.02) and cohort 2 vs 3 (3.7 vs 4.9 g/min, p = 0.03). In both cases, no significant differences were observed when comparing the following cohorts. Complication rate showed no significant differences throughout the caseload. CONCLUSIONS: In our single-surgeon experience, we observed a learning curve of nearly 60 cases for the ThuLEP procedure in presence of a well-trained surgeon. Complication rate was low from the beginning of surgical experience.

A proposed mathematical model to help preoperative planning between RIRS and MiniPerc for renal stones between 10 and 20 mm using holmium:Yag laser (Cyber Ho): the stone management according to size-hardness (SMASH) score.

To evaluate the performance of a mathematical model to drive preoperative planning between RIRS and MiniPerc (MP) for the treatment of renal stones between 10 and 20 mm. Patients with a renal stone between 10 and 20 mm were enrolled. A mathematical model named Stone Management According to Size-Hardness (SMASH) score was calculated: hounsfield units (HU) χ stone maximum size (cm)/100. Patients were divided into 4 groups: RIRS with score < 15 (Group A), RIRS with score ≥ 15 (Group B), MP with score < 15 (Group C), MP with score ≥ 15 (Group D). Cyber Ho device was always used. Stone free rate (SFR) was assessed after 3 months. Complication rate and need for auxiliary procedures were evaluated. Between January 2019 and December 2021, 350 patients were enrolled (87, 88, 82 and 93 in Groups A, B, C and D). Mean stone size was 13.1 vs 13.3 mm in Group A vs B (p = 0.18) and 16.2 vs 18.1 mm in Group C vs D (p = 0.12). SFR was 82%, 61%, 75% and 85% for Groups A, B, C and D. SFR was comparable between Groups C and D (p = 0.32) and Groups A and C (p = 0.22). SFR was significantly higher in Group A over B (p = 0.03) and in Group D over B (p = 0.02). Complication rate was 2.2%, 3.4%, 12.1%, 12.9% for Groups A, B, C, D. RIRS and MP are both safe and effective. The mathematical model with the proposed cut-off allowed a proper allocation of patients between endoscopic and percutaneous approaches.Registration number of the study ISRCTN55546280.

No side effects on rabbit retina or vitreous microenvironment by nd:YAG laser vitreolysis.

BACKGROUND: To explore the safety of Neodymium:Yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis based on the histological examination of the retina and the alteration of vitreous cytokines in the rabbits. METHODS: Nine male New Zealand rabbits underwent Nd:YAG laser vitreolysis of 10 mJ x 500 pulses in the left eyes, while the right eyes were used as controls. Intraocular pressure, color fundus photography, and ultrasound B scan were measured before, as well as 1 day, 4 weeks, and 12 weeks after Nd:YAG laser vitreolysis. Three rabbits were euthanized 1 day, 4 weeks, and 12 weeks after treatment, respectively. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and hematoxylin-eosin (H&E) staining were used to look for pathological changes in the retina. An enzyme-linked immunosorbent assay (ELISA) was utilized to detect the expression of vascular endothelial growth factor (VEGF) and some inflammatory cytokines, including interferon inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1) and interlenkin 6 (IL-6) in the vitreous humor. The ascorbic acid (AsA) and total reactive antioxidant potential (TRAP) in the vitreous humor were also measured. RESULTS: Following Nd:YAG laser vitreolysis, the levels of VEGF, IP-10, MCP-1, IL6, AsA, and TRAP in the vitreous humor did not change substantially (P > 0.05). There were no detectable pathological changes in the retinal tissues, and no apoptotic signal was found. CONCLUSIONS: Rabbits tolerate Nd:YAG laser vitreolysis without observable impact on retinal tissue or the microenvironment of the vitreous.

Efficacy and safety of first-line or second-line selective laser trabeculoplasty for normal-tension glaucoma: a multicentre cohort study.

BACKGROUND/AIMS: This study aimed to investigate and compare the efficacy and safety of first-line and second-line selective laser trabeculoplasty (SLT) in Japanese patients with normal-tension glaucoma (NTG). METHODS: 100 patients with NTG were enrolled in this study. Patients were treated with SLT as a first-line or second-line treatment for NTG. Main outcome measures were intraocular pressure (IOP) reduction rate, outflow pressure improvement rate (ΔOP), success rate at 1 year and complications. Success was defined as ΔOP≥20% (criterion A) or an IOP reduction ≥20% (criterion B) without additional IOP-lowering eye-drops, repeat SLT or additional glaucoma surgeries. The incidence of transient IOP spike (>5 mm Hg from the pretreatment IOP), conjunctival hyperaemia, inflammation in the anterior chamber and visual impairment due to SLT were assessed. RESULTS: A total of 99 patients (99 eyes) were initially enrolled in this study, including 74 eyes assigned to the first-line SLT group and 25 eyes to the second-line SLT group. The mean IOP of 16.3±2.1 mm Hg before SLT decreased by 17.1%±9.5% to 13.4±1.9 mm Hg at 12 months after SLT in the first-line group (p<0.001), and the mean IOP of 15.4±1.5 mm Hg before SLT decreased by 12.7%±9.7% to 13.2±2.0 mm Hg at 12 months after SLT (p=0.005) in the second-line group. Both groups showed significant reductions in IOP. Higher pre-SLT IOP and thinner central corneal thickness were associated with greater IOP reduction. The success rate at 1 year was higher in the first-line compared with the second-line group, with lower pretreatment IOP and the use of IOP-lowering medication before SLT being associated with treatment failure. Most post-treatment complications were minor and transient. CONCLUSIONS: SLT may be an effective and safe treatment option for NTG, as either a first-line or second-line treatment. TRIAL REGISTRATION NUMBER: The study was registered in the UMIN-CTR (UMIN Test ID: UMIN R000044059).

Laser therapy decreases oral leukoplakia recurrence and boosts patient comfort: a network meta-analysis and systematic review.

BACKGROUND: Oral leukoplakia (OLK) is a prevalent precancerous lesion with limited non-pharmacological treatment options. Surgery and various lasers are the mainstay of treatment; however, their relative efficacy and optimal choice remain unclear. This first network meta-analysis compared the effects of different lasers and surgical excision on post-treatment recurrence and comfort in OLK patients. METHODS: We searched four databases for relevant randomized controlled trials (RCTs) up to April 2023. The primary outcome was post-treatment recurrence, and secondary outcomes included intraoperative hemorrhage and postoperative pain scores. The Cochrane Risk of Bias tool was used to assess the study quality. Meta-analysis and network meta-analysis were employed to determine efficacy and identify the optimal intervention. RESULTS: A total of 11 RCTs including 917 patients and 1138 lesions were included. Er,Cr:YSGG laser treatment showed significantly lower recurrence rates compared to CO2 laser (OR: 0.04; 95% CI: 0.01-0.18), CO2 laser with margin extension (OR: 0.06; 95% CI: 0.01-0.60), Er:YAG laser (OR: 0.10; 95% CI: 0.03-0.37), electrocautery (OR: 0.03; 95% CI: 0.00-0.18), and standard care (OR: 0.08; 95% CI: 0.02-0.33). Er,Cr:YSGG laser also ranked the best for reducing recurrence, followed by standard care and CO2 laser combined with photodynamic therapy (PDT). Er:YAG and Er:Cr:YSGG lasers minimized bleeding and pain, respectively. None of the interventions caused severe adverse effects. CONCLUSION: For non-homogeneous OLK, Er:YAG, Er:Cr:YSGG, and CO2 laser combined with PDT offer promising alternatives to surgical excision, potentially reducing recurrence and improving patient comfort. Further high-quality RCTs are necessary to confirm these findings and determine the optimal laser-PDT combination for OLK treatment.

Effects of Thermal Insulation on Recovery and Comfort of Patients Undergoing Holmium Laser Lithotripsy.

BACKGROUND Patients with urolithiasis often undergo transurethral ureteroscopic holmium laser lithotripsy, a procedure that can be affected by perioperative thermal management. This study examines the impact of compound thermal insulation management on patient recovery and comfort during transurethral ureteroscopic holmium laser lithotripsy. MATERIAL AND METHODS In this study, 551 patients who underwent transurethral ureteroscopic holmium laser lithotripsy from April 2019 to December 2022 were randomly assigned to either an observation group (n=276) or control group (n=275). Both groups received routine surgical care, with the observation group additionally receiving compound thermal insulation management. We recorded and compared perioperative body temperature changes, anesthetic resuscitation indicators (bispectral index recovery time, extubation time, fully awake time, Postanesthesia Care Unit retention time), comfort level (General Comfort Questionnaire), and quality of life (Nottingham Health Profile). We also compared the incidence of complications. RESULTS There was no significant difference in body temperature between groups at the start surgery. However, the observation group showed significantly higher temperatures during and at the end of surgery. Anesthetic resuscitation indicators were significantly better in the observation group. Both groups showed improved comfort and quality of life after surgery, with more significant improvements in the observation group. The observation group also had a lower incidence of complications, such as hypothermia and rigor. CONCLUSIONS Compound thermal insulation management during transurethral ureteroscopic holmium laser lithotripsy improved perioperative temperature maintenance, accelerated postoperative recovery, reduced complication rates, and enhanced patient comfort and quality of life.

Histological evaluation of the surgical margins of oral soft tissue incisions using a dual-wavelength diode laser and an Er, Cr:YSGG laser; an ex vivo study.

OBJECTIVE: This study compared a dual-wavelength diode laser and an Er, Cr:YSGG laser in oral soft tissue incisions to determine the most effective and safest laser system at the histopathological level. METHODOLOGY: The (810 and 980 nm) dual-wavelength diode laser was used at 1.5 W and 2.5 W (CW) power settings, and the (2780 nm) Er, Cr:YSGG laser was used at 2.5 W and 3.5 W (PW) power settings. Both laser systems were used to incise the tissues of freshly dissected sheep tongue pieces to obtain the following histopathological criteria: epithelial tissue changes, connective tissue changes, and lateral thermal damage extent by optical microscopy. RESULTS: The epithelial and connective tissue damage scores were significantly higher in the dual-wavelength diode laser groups than in the Er, Cr:YSGG laser groups (P<0.001), and there was a significant difference between some groups. The extent of lateral thermal damage was also significantly higher in the diode laser groups than in the Er, Cr: YSGG laser groups (P<0.001), and there was a significant difference between groups. Group 2 (2.5 W) of the diode laser was the highest for all three criteria, while group 3 (2.5 W) of the Er, Cr:YSGG laser was the lowest. CONCLUSION: The Er, Cr:YSGG laser with an output power of 2.5 W is, histologically, the most effective and safest laser for oral soft tissue incision. The dual-wavelength diode laser causes more damage than the Er, Cr:YSGG laser, but it can be used with a low output power and 1 mm safety distance in excisional biopsy.

755-nm picosecond laser plus topical 20% azelaic acid compared to topical 20% azelaic acid alone for the treatment of melasma: a randomized, split-face and controlled trial.

PURPOSE: Melasma remains a refractory skin condition that needs to be actively explored. Azelaic acid has been used for decades as a topical agent to improve melasma through multiple mechanisms, however, there is a lack of research on its combination with laser therapy. This study evaluated the effectiveness of isolated treatment with topical 20% azelaic acid and its combination with 755-nm picosecond laser in facial melasma patients. METHODS: A randomized, evaluator-blinded, controlled study was conducted on 30 subjects with facial melasma in a single center from October 2021 to April 2022. All subjects received topical 20% azelaic acid cream (AA) for 24 weeks, and after 4 weeks, a hemiface was randomly assigned to receive 755-nm picosecond (PS) laser therapy once every 4 weeks for 3 treatments. Treatment efficacy was determined by mMASI score evaluations, dermoscopic assessment, reflectance confocal microscopy (RCM) assessments and patient's satisfaction assessments (PSA). RESULTS: Treatment with 20% azelaic acid, with or without picosecond laser therapy, significantly reduced the hemi-mMASI score (P < 0.0001) and resulted in higher patient satisfaction. Improvements in dermoscopic and RCM assessments were observed in both sides of the face over time, with no difference between the two sides. RCM exhibited better dentritic cell improvement in the combined treatment side. No patients had serious adverse effects at the end of treatment or during the follow-up period. CONCLUSION: The additional use of picosecond laser therapy showed no clinical difference except for subtle differences detected by RCM assessments.The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100051294; 18 September 2021).

[Treatment of early capsular blockage syndrome with Nd:YAG laser anterior capsulotomy containing neodymium-doped yttrium aluminum garnet in a case].

A 62-year-old female patient presented with no improvement in vision 10 days after undergoing cataract extraction in the right eye. The unaided visual acuity in the right eye was 0.1, and examination with a slit lamp revealed the presence of the intraocular lens with an increased gap between the intraocular lens and the posterior capsule. Anterior segment optical coherence tomography showed a distance of 3.236 mm between the posterior capsule and the posterior surface of the intraocular lens. Based on the medical history, ocular examination, and auxiliary examinations, a diagnosis of right eye capsular blockage syndrome was made. Nd:YAG laser capsulotomy was performed at the anterior capsule outside the optical zone of the intraocular lens. One week later, the posterior capsule adhered to the posterior surface of the intraocular lens, and there was a significant improvement in vision compared to before the procedure.

Use of a fractional 1570-nm diode laser scanner for non-ablative face and neck rejuvenation.

BACKGROUND: The use of non-ablative fractionated lasers for skin rejuvenation has been proven to be effective in improving skin texture, and has become popular due to minimal wounding, significantly shorter recovery times and decreased adverse effects. OBJECTIVE: To retrospectively analyze improvement in skin texture in healthy women aged over 18 years with Fitzpatrick skin types II-IV. METHODS: Participants received three facial and/or neck treatments with the 1570-nm fractional scanning diode laser at 1-month intervals. Three months after the last treatment session two blinded evaluators assessed skin improvement using before and after photos. Pain and patient satisfaction were recorded. RESULTS: Sixteen women with a mean age of 45.4 ± 4.1 years (range 35-50 years) and skin type II-IV were included in the analysis. All 16 participants received facial treatments and seven (43.8%) also received neck treatments. Three months follow-up evaluation showed that the majority of participants had a visible change in the treated areas. Mean pain score was low and decreased with each treatment session. CONCLUSION: Skin treatment using fractional scanning 1570-nm diode laser improves skin laxity in women with skin types II-IV. Larger studies are warranted to further clarify the efficacy and safety of this modality.

An in vitro assessment of the residual dentin after using three minimally invasive caries removal techniques.

To evaluate the efficiency and effectiveness of three minimally invasive (MI) techniques in removing deep dentin carious lesions. Forty extracted carious molars were treated by conventional rotary excavation (control), chemomechanical caries removal agent (Brix 3000), ultrasonic abrasion (WOODPECKER, GUILIN, China); and Er, Cr: YSGG laser ablation (BIOLASE San Clemente, CA, USA). The assessments include; the excavation time, DIAGNOdent pen, Raman spectroscopy, Vickers microhardness, and scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM-EDX). The rotary method recorded the shortest excavation time (p < 0.001), Brix 3000 gel was the slowest. DIAGNOdent pen values ranged between 14 and 18 in the remaining dentin and laser-ablated surfaces recorded the lowest reading (p < 0.001). The Ca:P ratios of the remaining dentin were close to sound dentin after all excavation methods; however, it was higher in the ultrasonic technique (p < 0.05). The bur-excavated dentin showed higher phosphate and lower matrix contents with higher tissue hardness that was comparable to sound dentin indicating the non-selectiveness of this technique in removing the potentially repairable dentin tissue. In contrast, the MI techniques exhibited lower phosphate and higher organic contents associated with lower microhardness in the deeper dentin layers. This was associated with smooth residual dentin without smearing and patent dentinal tubules. This study supports the efficiency of using MI methods in caries removal as conservative alternatives to rotary excavation, providing a promising strategy for the clinical dental practice.

Assessing renal tissue temperature changes and perfusion effects during laser activation in an in vivo porcine model.

INTRODUCTION: High fluid temperatures have been seen in both in vitro and in vivo studies with laser lithotripsy, yet the thermal distribution within the renal parenchyma has not been well characterized. Additionally, the heat-sink effect of vascular perfusion remains uncertain. Our objectives were twofold: first, to measure renal tissue temperatures in response to laser activation in a calyx, and second, to assess the effect of vascular perfusion on renal tissue temperatures. METHODS: Ureteroscopy was performed in three porcine subjects with a prototype ureteroscope containing a temperature sensor at its tip. A needle with four thermocouples was introduced percutaneously into a kidney with ultrasound guidance to allow temperature measurement in the renal medulla and cortex. Three trials of laser activation (40W) for 60 s were conducted with an irrigation rate of 8 ml/min at room temperature in each subject. After euthanasia, three trials were repeated without vascular perfusion in each subject. RESULTS: Substantial temperature elevation was observed in the renal medulla with thermal dose in two of nine trials exceeding threshold for tissue injury. The temperature decay time (t½) of the non-perfused trials was longer than in the perfused trials. The ratio of t½ between them was greater in the cortex than the medulla. CONCLUSION: High-power laser settings (40W) can induce potentially injurious temperatures in the in vivo porcine kidney, particularly in the medullary region adjacent to the collecting system. Additionally, the influence of vascular perfusion in mitigating thermal risk in this susceptible area appears to be limited.