In vivo biological safety investigation of Yb-CALGO femtosecond laser dental surgery.

While lasers have found their successful applications in various clinical specialties, in clinical dental practice, traditional mechanical drills are still predominantly utilized. Although erbium-doped lasers have been demonstrated for dental therapy, their clinical performance is still not satisfactory due to the long pulse width, low peak power, and small repetition rate. To attain a smaller thermal diffusion thus better biological safety and surgical precision, as well as more rapid ablation, the advancement of femtosecond laser techniques has opened another route of dental surgery; however, no biological safety investigation has been reported. Here, we present a systematic study of dental ablation by a Yb:CaAlGdO4 regenerative amplifier with a central wavelength of 1040 nm and pulse width of 160 fs. The in vivo experiment of dental surgery investigating the inflammatory response has been reported, for the first time to the best of our knowledge. It is demonstrated that dental surgery by Yb:CaAlGdO4 femtosecond laser ablation has better biological safety compared to the turbine drilling, thanks to its non-contact and ultrafast heat dissipation nature.

Investigating the efficacy of Endolift laser and Nanofat as a combination therapy for horizontal neck lines compared to Nanofat autologous alone.

BACKGROUND: The emergence of horizontal neck wrinkles is increasingly becoming a focal point for both cosmetic professionals and clients. Various treatment approaches must be considered to address this issue effectively, owing to its diverse underlying causes. The study explores the potential of utilizing the Endolift laser in conjunction with nanofat injection as a viable treatment option. METHODS: Twenty patients with horizontal neck wrinkles involved in the study. Ten patients underwent treatment with a combination of Endolift laser and nanofat injection and 10 patients treated with nanofat injection alone. The participants were monitored for 6 months post-treatment. Biometric measurements were utilized to assess outcomes, including changes in volume, depth, and area of the wrinkles, skin elasticity, as well as the diameter and density of the epidermis and dermis in the treated area. Skin improvement was evaluated by two independent dermatologists, who compared before and after photos in a blinded manner. Patient satisfaction levels were also documented. RESULTS: The Visioface analysis showed a notable decrease in neck wrinkle depth and area in both groups. However, the group receiving the combination treatment of Endolift laser and nanofat exhibited a significantly greater improvement compared to the group treated with nanofat alone. Skin ultrasonography results demonstrated an increase in thickness and density of the dermis and epidermis in both groups. Particularly, the group treated with Endolift laser-nanofat displayed significant enhancements in dermis and epidermis density and thickness when contrasted with the nanofat-only group. Analysis with Cutometer revealed a marked enhancement in skin elasticity in the Endolift-nanofat treated group in comparison to the nanofat-only treated group. Furthermore, in the Endolift-nanofat treated group, a substantial majority (90%) of patients exhibited improvement. Patient evaluations highlighted significant distinctions between the two groups, with 95% of patients in the Endolift-nanofat treated group demonstrating enhancement. CONCLUSION: Both methods notably enhance horizontal neck wrinkles; nevertheless, the combination of endolift laser and nanofat seems to be more efficient for treating horizontal neck wrinkles.

High-powered 675-nm laser: Safety and efficacy in clinical evaluation and in vitro evidence for different skin disorders.

BACKGROUND: Laser technology is a viable therapeutic option for treating a number of skin pathologic conditions, including pigmented lesions, vascular lesions and acne scars. AIM: In this work, through in vitro and clinical investigations we test the efficacy, the safety and the speed of treatment of high-powered laser system emitting a 675-nm in the management of various skin condition. MATERIALS AND METHODS: In vitro experiments were performed irradiating adult human dermal fibroblasts cells (HDFa) with 675-nm laser for 24, 48 and 72 h with different fluences and Ki-67+ cells were counted. The confocal microscopy images of control and treated samples were acquired. Clinical skin rejuvenation/diseases treatments with 675 nm laser device were performed with different laser parameters in 11 patients with pigmented lesions, 5 patients with acne scars and 23 patients for skin rejuvenation. Data were evaluated with the validated global score using 5-point scales (GAIS) and patient's satisfaction scale. RESULTS: The application of the high-power 675 nm laser has proven effective in stimulating cell proliferation in in vitro experiments and it led to good results for all skin pathologies. GAIS showed values between 3 and 4 points for all treated pathologies, all scores between '75%-good improvements' and '100%-excellent improvements'. The treatment time was reduced by 50% compared to the old parameters setting, resulting in a faster and good patient's satisfying technique. No serious adverse effects were recorded. CONCLUSION: the preclinical and clinical data confirm the efficacy and safety of this high-powered 675 nm laser for several skin condition.

Refractory solar lentigines successfully treated with 532-nm nanosecond Nd:YAG Vasculature Salvage Laser Surgery (VSLS) system: Case series.

BACKGROUND: Solar lentigo, a common epidermal hyperpigmented lesion found in sun-exposed areas, results from the proliferation of melanocytes and the accumulation of melanin. Although various treatments for solar lentigo have been explored, they often lead to complications, including prolonged erythema and post-inflammatory hyperpigmentation (PIH), posing significant concerns. OBJECTIVES AND METHODS: This study evaluated the safety and efficacy of the Vasculature Salvage Laser Surgery (VSLS) system. We treated six Korean patients, each with solar lentigo, in a single session using the 532-nm nanosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) VSLS system, with follow-up periods ranging from 3 to 10 weeks. RESULTS: The treatment led to the complete removal of pigmented lesions in all patients without resulting in PIH, even in cases where previous laser treatments had failed. The only side effect observed was mild erythema, which resolved over the long term in most instances. CONCLUSIONS: The VSLS system emerges as a safe and effective treatment for pigmented lesions, including refractory solar lentigines. Nonetheless, additional studies are required to verify its long-term efficacy.

Optical Effects of Focused Fractional Nanosecond 1064-nm Nd:YAG Laser: Techniques of Application on Human Skin.

BACKGROUND AND OBJECTIVES: Considering the pulse widths of picosecond and nanosecond lasers used in cutaneous laser surgery differ by approximately one order of magnitude, can nanosecond lasers produce the optical effect in human skin similar to laser-induced optical breakdown (LIOB) caused by picosecond lasers? METHODS: Cutaneous changes induced by a focused fractional nanosecond 1064-nm Nd:YAG laser were evaluated by VISIA-CR imaging, histological examination, and harmonic generation microscopy (HGM). RESULTS: A focused fractional nanosecond 1064-nm Nd:YAG laser can generate epidermal vacuoles or dermal cavities similar to the phenomenon of LIOB produced by picosecond lasers. The location and extent of photodisruption can be controlled by the laser fluence and focus depth. Moreover, laser-induced shock wave propagation and thermal degeneration of papillary collagen can be observed by HGM imaging. CONCLUSION: Focused fractional nanosecond lasers can produce an optical effect on human skin similar to LIOB caused by picosecond lasers. With techniques of application, the treatment can induce epidermal and dermal repair mechanisms in a tunable fashion to improve skin texture, wrinkles, scars, and dyspigmentation, without disrupting the epidermal surface.

Evaluation of a Novel Ablative 1940 nm Pulsed Laser for Skin Rejuvenation.

BACKGROUND: Skin rejuvenation is a widely sought-after goal, prompting advancements in laser technology for noninvasive and effective treatments. Ablative lasers, in particular, have evolved to address diverse skin concerns, with fractional ablative lasers offering better-tolerated outcomes. The introduction of a novel ablative Thulium pulsed laser, based on Thulium-doped Yttrium aluminum Perovskite (Tm:YAP) crystal, delivers precise and controlled skin rejuvenation by allowing customization of ablative microcolumns. METHODS: A pilot in vivo study was conducted on the abdominal skin of a live female pig. Using the Laser Team Medical (LTM) prototype laser, treatments were administered with varying coagulation settings (minimal and maximum) and energies (32, 80, 120, and 160 mJ per microcolumn). Biopsies were harvested, fixed, and stained for subsequent analysis. The penetration depth and width of the microcolumns were evaluated. RESULTS: Low coagulation settings produced ablative microcolumns with thermal affected zones of 160 µm width, while high coagulation settings resulted in wider zones of 400-530 µm. The ablation cavities' width was estimated to be less than 100 µm in both settings. The novel 1940 nm pulsed laser demonstrated superior microcolumn properties, offering potential advantages such as shorter downtime and increased efficacy compared to existing fractional ablative lasers. CONCLUSION: This study presents encouraging preliminary results regarding the efficacy and safety of the first ablative 1940 nm pulsed laser. The results show ablative microcolumns thinner than the counterpart devices, showing the device safety and potential higher efficacy along with short downtime. The LTM novel ablative 1940 nm pulsed laser holds immense potential for enhancing skin rejuvenation treatments due to its superior microcolumns properties. The versatility of this laser can open new treatment procedures and may extend to different areas of dermatology.

Complications of Chemical Peels, Lasers, and Energy-Based Device Procedures Performed by Core Cosmetic Physicians: A Retrospective Analysis.

BACKGROUND: There has been a proliferation of physicians of different levels of experience and training offering nonsurgical cosmetic procedures. Rising demand, compounded by increasing utilization of new and existing technologies by numerous physician specialties, compels discussion of adequate standardized training and patient safety. METHODS: A retrospective chart review of patients who presented to our single site dermatology clinic for managment of complications following chemical peel, laser or energy-based device treatments performed by core cosmetic physicians between the years of 2013 and 2024 was conducted. Core cosmetic physicians included plastic surgery, facial surgery/otolaryngology, oculoplastic surgery, and dermatology. Charts were reviewed for documentation of the type of complication, procedure causing the complication, and physician credentials, and referral source. RESULTS: Twenty-five patients were identified as having complications from chemical peeling, laser treatment or energy-based devices. Devices implicated included CO2 laser (fractional or fully ablative), chemical peels, 1064 nm long-pulsed Nd:YAG laser, 1320 nm Nd:YAG laser, intense pulsed light, 595 nm pulsed dye laser, Q-switched Nd:YAG laser, radiofrequency with and without microneedling, and 1550 nm erbium-doped fiber laser. Complications included hypertrophic scarring, atrophic scarring, post-inflammatory erythema, post-inflammatory hyperpigmentation, and post-inflammatory hypopigmentation. CONCLUSIONS: Even in experienced hands, complications can arise. It is imperative that all physicians offering cosmetic treatments are equipped to recognize clinical endpoints, identify and manage complications, or make a timely referral to decrease the risk of a permanent and potentially devastating esthetic outcome for patients.

Comparing Energy-Based Devices for Striae Improvement: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Striae distensae (SD) are cutaneous lesions that are caused by hormones or mechanical stress leading to rapid expansion of skin. Therefore, SD are now a cosmetic concern. However, improving SD is notoriously difficult. Among different treatments, energy-based devices (EBDs) are much more effective and controllable. OBJECTIVE: The aim of this review was to determine the most effective type of EBD for improving the appearance of striae. MATERIALS AND METHODS: The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The population comprised patients suffering from striae. Different types of EBDs used to improve striae were compared. The primary outcome of the reduction in the width of striae was evaluated. A random-effects model was performed. The means and standard deviations were extracted. RESULTS: Eighteen randomized controlled trials were included. The network meta-analysis revealed that after a comparison among the 4 types of EBDs, no significant differences were observed in the reduction of striae width. CONCLUSION: Radiofrequency, ablative lasers, nonablative lasers, and intense pulsed light are all effective treatments for reducing the striae width. None of them was superior to the others. However, radiofrequency and ablative lasers may have the highest chance of improving the appearance of striae.

Energy-Based Devices for the Treatment of Cutaneous Verrucae: A Systematic Review.

BACKGROUND: Warts are one of the most common benign neoplasms caused by human papillomavirus infection and often pose a therapeutic challenge. OBJECTIVE: To summarize the current evidence on the safety and efficacy of laser and energy-based devices for the treatment of cutaneous verrucae. METHODS: A comprehensive systematic review of the literature on laser and energy-based devices for the treatment of cutaneous verrucae was performed. RESULTS: A total of 904 unique studies were identified, of which 109 were included in this review. The most commonly used lasers as a single treatment modality for verrucae included the long-pulsed Nd:Yag (n = 20) and pulsed dye (n = 18) lasers. Other modalities included the CO2 ablative laser (n = 10), photodynamic therapy (n = 11), local hyperthermia (n = 11), microwave therapy (n = 2), and nanopulse stimulation (n = 1). Other studies combined energy-based modalities with additional treatments, such as retinoids, imiquimod, and intralesional bleomycin. Overall, such devices were generally well-tolerated, with only a mild side effect profile. CONCLUSION: Overall, the use of laser and energy-based devices is a safe and well-tolerated option for cutaneous verrucae that is relatively less invasive than surgical interventions. Future studies using more consistent outcome assessment tools will be valuable to help clinicians develop device-specific protocols and treatment regimens to ensure replicable and effective outcomes.

Review of Fractional Nonablative Lasers for the Treatment of Dermatologic Conditions in Darker Skin Phototypes.

BACKGROUND: Fractional nonablative lasers (NAFLs) have demonstrated efficacy and safety for treating dermatologic conditions in patients with darker skin phototypes. Nonablative lasers are preferred in darker skin tones due to lower risk of postinflammatory hyperpigmentation. OBJECTIVE: This review aims to identify the ideal laser options and parameters for treating common dermatologic conditions in patients with skin types IV-VI. MATERIALS AND METHODS: A comprehensive literature search was conducted on PubMed in May 2023. Of 1,065 articles were identified, and 40 articles met the inclusion criteria. The studies were classified based on design, dermatologic condition, and skin phototype of patients, and assigned levels of evidence according to the Modified Criteria of the Oxford Center of Evidence Based Medicine. RESULTS: Strong level 1 evidence supports the treatment of melasma and atrophic scars using NAFL. Moderate level 2 evidence was found for using NAFL in acne vulgaris, striae, and skin rejuvenation; 45% of the studies examined skin types III-IV, 20% III-V, 7.5% II-IV, 5% II-V, 5% IV alone, and 2.5% I-IV. CONCLUSION: Further research is needed to determine the optimal treatment modalities and parameters for skin types V and VI. Appropriate device selection and conservative treatment settings are crucial for optimizing outcomes and minimizing adverse events.

Bio-thermal response during laser haemorrhoidoplasty: an exclusive analytical and numerical approach for theoretical investigation.

Haemorrhoidal disease is identified by declension of the inflamed and bleeding of vascular tissues of the anal canal. Traditionally, haemorrhoids are associated with chronic constipation and the most common symptoms are irritation in anus region, pain and discomfort, swelling around anus, tender lumps around the anus and rectal bleeding (depending upon the grade of haemorrhoid). Among the several conventional treatment procedures (commonly mentioned as, rubber band litigation, sclerotherapy and electrotherapy), laser haemorrhoidoplasty is an out-patient and less-invasive laparoscopic procedure. From literature survey it has been observed that an exclusive theoretical model depicting the impact of 1064 nm wavelength laser wave on living tissues subjected to haemorrhoid therapy is not available. This research work is a pioneering attempt to develop a theoretical study attributing specifically on laser therapy of haemorrhoid treatment based on Pennes' biological heat transfer model. The corresponding mathematical model has been solved by analytical method to establish thermal response of tissue during the treatment and also the same has been solved a numerical approach based on finite difference method to validate the feasibility of former method due to unavailability of any theoretical model. Impact of variation of blood perfusion term, laser pulse time and optical penetration depth on temperature response of skin tissue is captured. The tissue temperature decreases along with time of laser exposure with increasing the blood perfusion rate as it carries away large amount of heat. With the increase in laser pulse time, tissue temperature declines due to shorter pulse time resulting in higher energy consumed by electrons. The research outcome is successfully validated with less than 1% of error observed between the appointed analytical and numerical scheme.

The cutting-edge roles of lasers in endodontics: A bibliometric and scientometric analysis of the 100 most-cited articles.

PURPOSE: This bibliometric and scientometric analysis aimed to delve into the forefront roles of lasers in endodontics from 1990 to 2024. METHODS: A comprehensive electronic search was conducted using "Clarivate Analytics Web of Science, All Databases" to retrieve the most-cited articles pertaining to the topic. These articles were then ranked in descending order according to their citation counts and the top 100 were selected for further analysis. Parameters including citation density, publication year, journal, journal impact factor (IF), country, institution, author, study design, study field, evidence level, laser type, and keywords were meticulously analyzed. RESULTS: The mean and standard deviations of total citation and citation density were 106.47 ± 65.76 and 7.61 ± 5.13, respectively. Positive and negative correlations were found between the number of citations and citation density and age of publication. While the mean number of citations was significantly higher in the period 2001-2010 compared to the other periods (P < 0.05), values were similar between the periods 1990-2000 and 2011-2014 (P > 0.05). Articles were mainly published in the Journal of Endodontics. The most productive country, institutions, and author were the United States, the University of Showa, and Koukichi Matsumoto. Diode and Er: YAG lasers were commonly investigated. Ex vivo studies were mainly performed followed by in vitro ones. The main study field was "antimicrobial effect". Among keywords, "photodynamic therapy" was used more frequently. CONCLUSION: Lasers are predominantly utilized to leverage their antimicrobial efficacy. Advancements in technology will lead to improvements in the properties of lasers, thereby enhancing the disinfection of the root canal system.

Preclinical assessment of a mathematical model for ablation zone prediction in thyroid laser ablation.

To develop and validate a 3D simulation model to calculate laser ablation (LA) zone size and estimate the volume of treated tissue for thyroid applications, a model was developed, taking into account dynamic optical and thermal properties of tissue change. For validation, ten Yorkshire swines were equally divided into two cohorts and underwent thyroid LA at 3 W/1,400 J and 3 W/1,800 J respectively with a 1064-nm multi-source laser (Echolaser X4 with Orblaze™ technology; ElEn SpA, Calenzano, Italy). The dataset was analyzed employing key statistical measures such as mean and standard deviation (SD). Model simulation data were compared with animal gross histology. Experimental data for longitudinal length, width (transverse length), ablation volume and sphericity were 11.0 mm, 10.0 mm, 0.6 mL and 0.91, respectively at 1,400 J and 14.6 mm, 12.4 mm, 1.12 mL and 0.83, respectively at 1,800 J. Gross histology data showed excellent reproducibility of the ablation zone among same laser settings; for both 1,400 J and 1,800 J, the SD of the in vivo parameters was ≤ 0.7 mm, except for width at 1,800 J, for which the SD was 1.1 mm. Simulated data for longitudinal length, width, ablation volume and sphericity were 11.6 mm, 10.0 mm, 0.62 mL and 0.88, respectively at 1,400 J and 14.2 mm, 12.0 mm, 1.06 mL and 0.84, respectively at 1,800 J. Experimental data for ablation volume, sphericity coefficient, and longitudinal and transverse lengths of thermal damaged area showed good agreement with the simulation data. Simulation datasets were successfully incorporated into proprietary planning software (Echolaser Smart Interface, Elesta SpA, Calenzano, Italy) to provide guidance for LA of papillary thyroid microcarcinomas. Our mathematical model showed good predictability of coagulative necrosis when compared with data from in vivo animal experiments.

The features of the reparative regeneration of an oral mucosa wound created under the exposure of a laser at a wavelength of 445 nm (a pilot study).

In clinical practice, an innovative laser technology that provides contactless preparation of soft tissues with a wavelength of 445 nm has been introduced. This study aimed to investigate the morphological changes in the oral mucosa when exposed to laser radiation at a wavelength of 445 nm in the ablation mode.An experimental study was conducted to analyze the dynamics of reparative regeneration in the wound caused by that particular type of radiation, utilizing the procedure of lower lip frenuloplasty as an illustration. 48 sexually mature male laboratory rats were chosen as the research object. The procedure of preparing the oral vestibule was executed by employing a contactless laser beam with a wavelength of 445 nm and a power of 0.7 W in continuous mode (CW) and an uninitiated fiber.Histological examination showed that 25 min after the surgery, there were large areas of coagulation necrosis in the oral mucosa in the area affected by the blue laser. In 48 h, the area of necrosis decreased both in size and depth. By the 7th day after the surgery, the necrotic masses had grown into the connective tissue, while marginal regeneration of the epithelium was noted. By the 14th day, the wound surface was completely epithelialized, represented by fibrous scar tissue. Clinically, around the mandibular incisors, there was a wide area of attached keratinized gingiva.The findings of histological examination indicate a necrosis of coagulation type in the region of tissue ablation and also show the absence of phase II of the inflammatory response (the stage of exudation), which expedites the process of epithelialization of the oral mucosa wound.

Endovenous laser ablation (EVLA) 980 nm versus 1470 nm and the impact of fiber type: a systematic review and meta-analysis.

We sought to assess the efficacy and safety of endovenous laser ablation utilizing a 980 nm device versus a 1470 nm device in the treatment of lower limb venous insufficiency. We performed a systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. A research on PubMed, Scopus and Web of science for articles published by January 2024 was conducted. The primary endpoint was great saphenous vein (GSV) and truncal vein occlusion. Eleven studies encompassing 3061 patients and 3193 truncal veins, were included. The 1470 nm device demonstrated superior truncal vein and GSV occlusion outcomes compared to the 980 nm device at the early, one-year, and medium to long-term follow-up intervals. Odds ratios (OR) were 2.79(95%CI:1.31-5.94), 2.22(95%CI:1.21-4.07), and 2.02(95%CI:1.24-3.29) for truncal veins and 2.54(95%CI:1.119-5.41), 2.06(95%CI:1.07-3.95) and 2.04(95%CI:1.25-3.33) for GSV, across the respective intervals. While both devices demonstrated minimal, deep vein thrombosis (DVT), endovenous heat-induced thrombosis (EHIT) ≥ 2, and burn estimates, the 1470 nm device exhibited improved paresthesia, risk ratio (RR), 0.51(95%CI:0.34-0.77) and pain outcomes, standardized mean difference (SMD), -0.62(95%CI:-0.99to-0.25). Subgroup analysis displayed enhanced occlusion outcomes with the 1470 nm device for the six-month and one-year intervals, irrespective of fiber type. Radial fibers were associated with improved paresthesia outcomes (ß=-0.9520,p = 0.03). This review emphasized the enhanced efficacy of the 1470 nm device over the 980 nm device, regardless of fiber type. Radial fibers showed promise for improved paresthesia outcomes, suggesting similar safety profiles for both systems. Conclusive remarks on pain outcomes were impeded by data limitations.

Complications of dermatologic lasers in high Fitzpatrick phototypes and management: an updated narrative review.

This article explores the intricacies of laser surgery, acknowledging inherent risks and complications. Patients with higher Fitzpatrick phototypes, characterized by unique biological traits, face heightened vulnerability during laser treatments. Limited experience with darker skin tones necessitates a higher level of laser expertise and a conservative approach. The study aims to comprehensively review laser therapy's side effects and complications, with a specific focus on Fitzpatrick phototypes IV through VI. We searched the MEDLINE database from 1972 to 2023 to consolidate knowledge. Results illuminate nuanced challenges associated with laser surgery in higher phototypes. In conclusion, this research emphasizes the need for enhanced expertise and caution in laser procedures for individuals with darker skin, offering valuable insights to optimize patient safety and outcomes.

Nanosecond infrared laser (NIRL) for cutting roots of human teeth: thermal effects and quality of cutting edges.

A nanosecond infrared laser (NIRL) was investigated in cutting dental roots. The focus of the investigation was defining the preparation accuracy and registration of thermal effects during laser application. Ten teeth were processed in the root area using a NIRL in several horizontal, parallel incisions to achieve tooth root ablation as in an apicoectomy. Temperature change was monitored during ablation and the quality of the cutting edges in the roots were studied by means of micro-CT, optical coherence tomography, and histology of decalcified and undecalcified specimens. NIRL produced clearly defined cut surfaces in dental hard tissues. The automated guidance of the laser beam created regular, narrow dentin defects that tapered in a V-shape towards the ablation plane. A biologically significant increase in the temperature of the object and its surroundings did not occur during the laser application. Thermal dentin damage was not detected in histological preparations of treated teeth. Defined areas of the tooth root may be ablated using a NIRL. For clinical translation of NIRL in apicoectomy, it would be necessary to increase energy delivered to hard tissue and develop beam application facilitating beam steering for oral treatment.

The ideal range of laser hair removal for microtia patients undergoing two-stage ear reconstruction.

Although the technologies for auricular reconstruction in microtia have improved, issues such as low hairlines or excessive hair growth can still pose aesthetic problems for the reconstructed ear. Laser depilation has been reported as a solution for hair problems. However, few studies have discussed the appropriate region for hair removal. A retrospective analysis was performed on 276 patients with unilateral microtia who underwent the Nagata two-stage ear reconstruction. The gender ratio of male to female was 2.5 (198 males/78 females). Intense pulsed light depilation was used to remove hair. To determine the proper hair removal area, we measured the extent of hair removal. Before the first stage, the average vertical distance between the upper point (after localization) and hairline was 3.42 ± 4.75 mm (-10-20 mm). After the first stage, the average vertical distance between the upper point of the reconstructed ear and the hairline was 1.27 ± 2.41 mm (-10-15 mm). By using chi-square test to assess differences in hair removal success rates among various regions, we aimed to identify the suitable depilation region. Before the first stage, a depilation vertical distance ≥ 10 mm led to a 92.1% success rate. After the first stage surgery, among the patients needing additional hair removal, a vertical depilation distance ≥ 4 mm resulted in an 81.3% success rate. Based on our observation, we suggested that a depilation region of ≥ 10 mm (before the first surgery) or ≥ 4 mm (after the first surgery) would be the ideal range for laser hair removal.

Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser treatment in ophthalmology: a review of the most common procedures Capsulotomy and Iridotomy.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064 nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.

Ex-vivo parametric study of laser ablation-based drilling of cortical bone.

Frequently orthopedic surgeries require mechanical drilling processes especially for inserted biodegradable screws or removing small bone lesions. However mechanical drilling techniques induce large number of forces as well as have substantially lower material removal rates resulting in prolong healing times. This study focuses on analyzing the impact of quasi-continuous laser drilling on the bone's surface as well as optimizing the drilling conditions to achieve high material removal rates. An ex-vivo study was conducted on the cortical region of desiccated bovine bone. The laser-based drilling on the bovine bine specimens was conducted in an argon atmosphere using a number of laser pulses ranging from 100 to 15,000. The morphology of the resulting laser drilled cavities was characterized using Energy dispersive Spectroscopy (EDS) and the width and depth of the drills were measured using a laser based Profilometer. Data from the profilometer was then used to calculate material removal rates. At last, the material removal rates and laser processing parameters were used to develop a statistical model based on Design of Experiments (DOE) approach to predict the optimal laser drilling parameters. The main outcome of the study based on the laser drilled cavities was that as the number of laser pulses increases, the depth and diameter of the cavities progressively increase. However, the material removal rates revealed a decrease in value at a point between 4000 and 6000 laser pulses. Therefore, based on the sequential sum of square method, a polynomial curve to the 6th power was fit to the experimental data. The predicted equation of the curve had a p-value of 0.0010 indicating statistical significance and predicted the maximum material removal rate to be 32.10 mm3/s with 95%CI [28.3,35.9] which was associated with the optimum number of laser pulses of 4820. Whereas the experimental verification of bone drilling with 4820 laser pulses yielded a material removal rate of 33.37 mm3/s. Therefore, this study found that the carbonized layer formed due to laser processing had a decreased carbon content and helped in increasing the material removal rate. Then using the experimental data, a polymetric equation to the sixth power was developed which predicted the optimized material removal rate to occur at 4820 pulses.