Lasers in Medical Science

Correction to: Role of low-level laser therapy added to facial expression exercises in patients with idiopathic facial (Bell’s) palsy The published version contains a mistake in Figure 1. Below is the correct figure.

Methodological correctness of a recent publication on pain entitled “Evaluating the effect of photobiomodulation with a 940-nm diode laser on post-operative pain in periodontal flap surgery”

Laser-assisted hatching and clinical outcomes in frozen-thawed cleavage-embryo transfers of patients with previous repeated failure Abstract Assisted hatching (AH) is initially developed to provide an artificial manipulation of the zona pellucida (ZP) to help embryos hatch and improve the capacity of the embryos to implant. However, these effects remain unclear and controversial because of variation in patient characteristics, and it is critical to ascertain the indications for AH and to identify those patients who might benefit from AH. Here, this study aimed to assess the effect of laser-assisted zona thinning hatching technology (LAH) during the frozen-thawed D3 embryos on pregnancy outcomes in patients with previous repeated failures in vitro fertilization-embryo transfer (IVF-ET). To the best of our knowledge, these relationships have not been previously investigated. A retrospective cohort analysis was carried out. Infertility patients with previous repeated failure who underwent assisted reproductive therapy at our in vitro fertilization (IVF) center from May 2014 to May 2016 were enrolled. A total of 415 cleavage FET cycles (225 in the LAH group and 190 in the control group) were analyzed. Clinical outcomes including clinical pregnancy, implantation, live birth, miscarriage, and multiple gestation rates after transfer were compared between the LAH and control groups. The clinical pregnancy (49.3% versus 38.9%) and implantation rates (31.2% versus 24.6%) were significantly higher for the LAH group than the control group (P < 0.05). The live birth (44.8% versus 35.8%), multiple pregnancy (32.4% versus 31.0%), preterm birth (22.8% versus 17.1%), miscarriage (7.2% versus 5.4%), and ectopic rates (1.9% versus 0%) did not differ significantly between the two groups (P > 0.05). This study showed that LAH via zona pellucida (ZP) thinning significantly improves clinical outcomes, particularly clinical pregnancy and implantation rates, associated with FET cycles among patients with previous repeated failure.

Performance of light-emitting diode device in detecting occlusal caries in the primary molars Abstract This in vitro study aimed to compare the performance of a light-emitting diode (LED) device (Midwest Caries I.D.: MID), International Caries Detection and Assessment System (ICDAS) visual criteria, and fluorescence-based devices (DIAGNOdent: LF; DIAGNOdent pen: LFpen; and Quantitative Light-induced Fluorescence: QLF) in detecting occlusal caries in the primary molars. Eighty-eight primary molars with sound occlusal surfaces or carious lesions at different stages were assessed twice, with a 1-week interval in between, by one examiner using all three methods. Subsequently, the teeth were sectioned and lesion depth was verified using stereomicroscopy as a gold standard. Sensitivity, specificity, and accuracy were calculated at D1 (all carious lesions—enamel and dentin) and D3 (dentin lesions) thresholds. Correlation with histological analysis was evaluated using Spearman’s rank correlation coefficients (rho). Weighted Kappa and intraclass-correlation (ICC) coefficients were calculated to assess intra-examiner reproducibility. At D1 threshold, ICDAS and LFpen showed higher sensitivity than the other methods, whereas ICDAS, LF, and QLF showed higher specificity (p < 0.05), and MID showed lower accuracy. At D3 threshold, ICDAS, LFpen, and QLF showed higher sensitivity than MID, whereas ICDAS, LF, and MID showed higher specificity (p < 0.05). All methods, except MID, showed statistically similar accuracy values (p < 0.05). Correlations with histopathological analysis varied from 0.15 (MID) to 0.57 (ICDAS). Intra-examiner reproducibility varied from 0.30 (MID) to 0.92 (ICDAS, LF, and QLF). The MID device exhibited a poor performance in detecting occlusal carious lesions in the primary molars, and ICDAS visual criteria exhibited greater accuracy than LF, LFpen, and QLF devices.

Sub-lethal antimicrobial photodynamic inactivation: an in vitro study on quorum sensing-controlled gene expression of Pseudomonas aeruginosa biofilm formation Abstract During antimicrobial photodynamic inactivation (APDI) in the treatment of an infection, it is likely that microorganisms would be exposed to sub-lethal doses of APDI (sAPDI). Although sAPDI cannot kill microorganisms, it can significantly affect microbial virulence. In this study, we evaluated the effect of sAPDI using methylene blue (MB) on the expression of genes belonging to two quorum sensing (QS) operons (rhl and las systems) and two genes necessary for biofilm formation (pelF and pslA) under QS control in Pseudomonas aeruginosa. Biofilm formation ability of P. aeruginosa ATCC 27853 exposed to sAPDI (MB at 0.012 mM and light dose of 23 J/cm2) was evaluated using triphenyl tetrazolium chloride (TTC) assay and scanning electron microscopy (SEM). The effect of sAPDI on expression of rhlI, rhlR, lasI, lasR, pelF, and pslA were also evaluated by quantitative real-time polymerase chain reaction. Quantitative assay (TTC) results and morphological observations (SEM) indicated that a single sAPDI treatment resulted in a significant decrease in biofilm formation ability of P. aeruginosa ATCC 27853 compared to their non-treated controls (P = 0.012). These results were consistent with the expression of genes belonging to rhl and las systems and pelF and pslA genes. The results suggested that the transcriptional decreases caused by MB-sAPDI did lead to phenotypic changes.

Clinical efficacy of laser combined with menstrual regulation in the treatment of female melasma: a retrospective study Abstract The aim of this study was to evaluate the clinical efficacy of using a Medlite C6 Q-switch Nd:YAG laser combined with menstrual regulation–based traditional Chinese medicine (TCM) in the treatment of female melasma. Forty cases of female patients with melasma, who were treated between December 2013 and December 2015 at the Jiangsu Provincial Hospital of Traditional Chinese Medicine, were reviewed retrospectively. Twenty patients received Q-switch Nd:YAG 1064 nm laser treatments combined with menstrual regulation treatments (experimental group), and 20 patients were treated only with the laser (control group). All treatments lasted for 6 months. The patients’ faces were photographed before, immediately, and 6 months after treatment. The therapeutic efficacy was assessed by the reduction in the Melasma Area and Severity Index (MASI) score and the total skin damage score, and this was then compared between the two groups. Immediately and 6 months after the treatment, both the MASI and total skin damage scores in the experimental group were significantly lower compared to those in the control group (P < 0.001). The experimental group had significantly higher basic recovery and effectiveness rates than the control group (P = 0.020 and P = 0.008, respectively) and had a significantly lower invalidity rate (P < 0.001). Results from Medlite C6 Q-switch Nd:YAG laser treatment combined with menstrual regulation are superior than those obtained using only a laser for the treatment of female melasma.

The efficacy of green light laser prostatectomy in the management of urinary retention due to prostate hyperplasia Abstract To evaluate the efficacy and safety of 120 W potassium titanyl phosphate (KTP) in the treatment of urinary retention (UR) due to benign prostate hyperplasia in high-risk patients. Forty-six male patients with mean age of 73.78 ± 9.82 years who اhad UR and underwent 120 W KTP laser vaporization of the prostate between January 2015 and June 2017 were included. We evaluated perioperative parameters including serum prostate specific antigen, prostate volume, period of postoperative catheterization, vaporization time, delivered energy, hospitalization period, as well as intraoperative and postoperative complications. In the follow-up protocols, International Prostate Symptom Score and quality-of-life questionnaire (IPPS-QoL) and postvoid residual volume (PVR) were also assessed. The mean follow-up period was 15.57 ± 9.26 (1–42) months. All patients get rid of UR, except 1 patient (2.1%) remained on Foley catheter and standard TURP was done. Mean vaporization time was 8.57 ± 4.19 min, and mean energy delivered was 51.7 ± 29.9 kJ. No intraoperative complications were observed and no blood transfusion was done. The mean postoperative IPSS at the last follow-up was 9.64 ± 6.65 and the QoL score was 1.61 ± 1.31. Green light laser prostatectomy is a safe, simple, and effective procedure for the treatment of UR secondary to BPH in high-risk patients. Short hospitalization, low rate of intra operative and postoperative complications with rapid improvements in the objective, and subjective voiding parameters are important considerations of this procedure.

Persistent Pixel Stamping Marks: a novel complication of fractional CO 2 laser in scar treatment Abstract Fractional CO2 laser rejuvenation of scars offers a high safety profile. Laser marks usually disappear clinically within 1 week. The authors observed occasional persistence of the laser marks on the scar surface. The purpose of this study is to report the incidence and to describe the clinical, dermoscopic, and histological features of a novel observed complication of fractional CO2 laser scar rejuvenation “Persistent Pixel Stamping Marks (PPSM)”.One hundred seventy-one cases were consecutively recruited from patients assigned for fractional CO2 laser scar rejuvenation. Patients who developed the phenomenon 1 month post laser session were recorded and subjected to clinical photography, dermoscopy, and optical coherence tomography (OCT) as well as a 4-mm punch biopsy from pixelated scars. The evolution of PPSM was followed up for 6 months. PPSM developed in 16 patients (9.4%), 15 of which were post burn hypertrophic scars. PPSM was significantly related to darker skin type, darker scar color, and longer scar duration. Histopathological findings included characteristic holes in stratum corneum and superficial dermis, thick collagen bundles perpendicular to the skin surface with loss of elastic tissue, focal interface changes, and triangular focus of fibroblastic proliferation. The marks disappeared in 5 and lasted in 11 patients. Their longevity was significantly related to longer dwell times and lower densities. PPSM represent miniature scarring at the sites of the microscopic thermal zones or a sign of their delayed healing. They tend to follow fractional CO2 laser resurfacing of hyperpigmented, long-standing burn scars. Longer dwell times and lower densities make them last longer.

Impact of lens density and lens thickness on cumulative dissipated energy in femtosecond laser–assisted cataract surgery Abstract To evaluate the required cumulative dissipated energy (CDE) to fragment the crystalline lens in femtosecond laser–assisted cataract surgery (FLACS) in relation to lens density and lens thickness. Consecutive eyes that underwent FLACS between September 2014 and March 2017 by a single surgeon using in all cases the same femtosecond laser and phacoemulsification platform were included in our retrospective study. Prior to surgery, corrected distance visual acuity (CDVA), optical biometry corneal, and crystalline lens tomographies were performed to assess anterior chamber depth (ACD), axial length (AL), and crystalline lens parameters (i.e., lens density, thickness, and nucleus staging (NS)). After surgery, CDE was calculated and analyzed in relation to lens density (LD) and lens thickness (LT). Zero ultrasound expenditure cases were recorded and their occurrence analyzed. The chart review identified 236 eyes of 200 patients, 98 males and 102 females aged 65± 15 years which were included in the study. Mean LD was 11.26 ± 2.05 pixel intensity units (range 7.30–18.80), and the mean LT was 3417 ± 405.17 μm (range 2545–4701). LD and LT correlated moderately (r = 0.50, p < 0.001) and weakly (r = 0.23, p < 0.001), with post-laser CDE. Higher LD and LT were also associated with lower rates of zero phaco (eyes in which no phacoemulsification energy was necessary). Furthermore, NS (r = 0.528, p < 0.001) and CDVA (r = − 0.3524, p < 0.001) also correlated with CDE. Higher LD, LT, NS values, and low CDVA are associated with higher ultrasound expenditure (CDE—cumulative dissipated energy) and with lower rates of zero ultrasound expenditure during FLACS.

Lasers for Becker’s nevus Abstract Becker’s nevus is a common pigmented dermatosis, usually featured by ipsilateral pigmented patch with hypertrichosis. Becker’s nevus is often treated with various types of lasers although other regimens are available. However, clinical outcomes appear inconsistent among studies. To summarize the clinical outcomes of Becker’s nevus treated with lasers via literature review. A variety of lasers had been used alone or in combination to treat Becker’s nevus. Laser wavelengths used for Becker’s nevus ranged from 504 to 10,600 nm, while the number of treatment varied from 1 to 12 sessions. The clinical outcomes were mixed although combination of lasers with different wavelengths appeared to achieve a better efficacy. Adverse effects were usually mild to moderate erythema. While lasers are relatively safe, their efficacy for Becker’s nevus is moderate. It seems that combination therapy could improve the outcome. However, trials in larger group of patients are required to validate the efficacy of each type of lasers for Becker’s nevus.