Excimer laser ablation of fibrocartilage: an in vitro and in vivo study

To date, lasers have found only limited applications in orthopedics. We employed a 308 nm XeCl excimer laser for ablation of fibrocartilage, in order to investigate the feasibility of excimer laser assisted meniscectomy. Experiments were conducted both in vitro and in vivo. For the in vitro study, human menisci, obtained during surgery and autopsy, were irradiated via a 600 microns core fiber at radiant exposures ranging between 20 mj/mm2 and 80 mj/mm2, at 20 Hz. Ablation rate measurements and histological analysis of the samples were performed. The ablation rates were found to range from 3 microns/pulse to 100 microns/pulse depending on the radiant exposure and/or the applied pressure on the fiber delivery system. Thermographic analysis was also performed during pulsed excimer as well as CW Nd:Yag and CW CO2 laser irradiation. Temperatures were lower for excimer laser (Tmax less than 65 degrees) than CW ND: Yag (Tmax less than 210 degrees) or CW CO2 (Tmax less than 202 degrees) laser. For the in vitro study, medial meniscectomy was performed in 15 rabbits with the excimer laser and a CW Nd:Yag laser in the right and left knee respectively. Excimer laser irradiation was performed at 70 mj/mm2. Nd:Yag irradiation was performed via a 600 microns core fiber at power outputs between 20 to 40 W for 10 and 20 seconds duration. The healing response to injury was investigated by histological analysis of the menisci after 1 day, 1, 2, 4, and 8 weeks following the laser procedure. Excimer laser treated menisci showed less inflammatory reaction and noticeable repair with minimal inflammatory response.(ABSTRACT TRUNCATED AT 250 WORDS)     

308 nm准分子紫外光治疗斑秃的效果

目的 探究对斑秃患者采用308 nm准分子紫外光治疗的临床效果。方法 选择我院2018年10月-2023年 10月收治的80例斑秃患者为研究对象,按随机数字表法分为对照组和观察组,每组40例。对照组给予 常规药物治疗,观察组在对照组的基础上给予308 nm准分子紫外光治疗,比较两组临床疗效、并发症 发生情况、治疗满意度、斑秃面积及毛发密度。结果 观察组治疗总有效率为97.50%,高于对照组的 80.00%,差异有统计学意义（P ＜0.05）;观察组并发症发生率为0,低于对照组的12.50%,差异有统 计学意义（P＜0.05）;观察组治疗满意度为95.00%,高于对照组的80.00%,差异有统计学意义（P＜0.05）; 观察组斑秃面积小于对照组,毛发密度大于对照组,差异有统计学意义（P＜0.05）。结论 308 nm准分子 紫外光治疗斑秃的效果良好,可有效改善患者的斑秃症状,缩小斑秃面积,改善毛发密度,且治疗后并发 症发生几率较低,安全性较高,有利于提高患者满意度。     

Excimer ablation of human intervertebral disc at 308 nanometers

Excimer laser energy, which has been shown to photoablate tissue at a precisely controllable rate with minimal thermal damage, was applied to human intervertebral disc in an effort to develop a technique for percutaneous discectomy. Cadaveric samples of human disc were used. Excimer laser energy was produced by a XeCl, magnetically switched, long-pulse laser working at 308 nm, 20 Hz. Annulus tissue of approximately 1 mm thickness was placed in contact with the output tip of a 400 microns core diameter quartz fiber, and measurements of ablation rate were made at different radiant exposures. Ablation rates were found to vary linearly with radiant exposure, from 0.7 micron/pulse at 10 mJ/mm2 to 11.0 microns/pulse at 55 mJ/mm2, with a correlation coefficient of 0.984. Threshold radiant exposure, calculated by extrapolation, was found to be about 7 mJ/mm2. Histologic analysis showed a minimum of thermal damage in these specimens, and when ablated with modification to maintain constant fiber-tissue contact, thermal injury was nearly absent, as compared to samples ablated with Nd:YAG through a contact probe. Thermographic analysis, performed using the AGA 782 Digital Thermography system, showed increasing temperature with increasing radiant exposure, with a maximum temperature of 47.2 degrees C at 55 mJ/mm2. In that precise tissue ablation was demonstrated with minimal generated heat, and excimer energy at 308 nm is transmissible through fiber optics, excimer holds great promise for the development of a percutaneous discectomy technique.     

193 nm excimer laser ablation of bone

The argon fluoride excimer laser is investigated as a cutting-ablating tool for bone surgery. Quantitative measurements are presented for various fluences of laser energy and number of pulses. Histological data are presented that demonstrate the minimal damage to the surrounding material from the laser interaction. Comparisons are made for non-decalcified and decalcified bone. The differences observed, as a function of decalcification in the fluences required for specified depth penetration, are noted and a possible explanation is suggested.     

单用308nm准分子激光与联合他卡西醇治疗白癜风的疗效对比观察

目的 比较单用308nm准分子激光疗法治疗白癜风与联合局部应用维生素D3类似物他卡西醇治疗白癜风的疗效和安全性。方法 用单盲、自身对照的方法对78例稳定期泛发性的白癜风患者的自身对称或相邻的皮损采用308nm准分子激光治疗,实验组联合外用他卡西醇软膏,对照组用安慰剂软膏,1个月观察1次,拍照对比疗效,对78例患者进行治疗后评价。结果 不同治疗部位疗效评价：实验组头面、躯干、四肢皮损的总有效率分别为93．5l％,84．16％,42．35％,对照组总有效率分别为90．90％,77．45％,34．15％（P〈0．05）;不同类型的皮损治疗效果比较：实验组寻常型和节段型皮损总有效率分别为86．80％,93．33％,对照组分别为73．81％,84．00％（P〈0．05）;照光次数和累积照光剂量比较：实验组最初色素再生时照光次数和光累积量分别为（16．15±3．22）次和（4．40±5．03）J／cm＾2,对照组分别为（18．56±3．50）次和（6．60-i-1．01）J／cm。（P〈0．05）,显效的患者实验组为（20．36±1．50）次和（7．50±3．54）J／cm＾2,对照组为（21．68±2．40）次和（8．80±9．24）J／cm＾2（P〈0．05）。结论 308nm准分子激光治疗白癜风有效而且安全,联合他卡西醇外用可以提高白癜风患者的治疗反应,增强308nm准分子激光的疗效,缩短色素再生的时间,减少照光的能量。     

Follow-up survey of 308-nm laser treatment of psoriasis

BACKGROUND AND OBJECTIVES: UVB treatment with a 308-nm excimer laser is a new treatment modality for localized psoriasis. The purpose of this study is to assess patients' impressions and satisfaction with 308-nm laser treatment of mild to moderate psoriasis. STUDY DESIGN/MATERIALS AND METHODS: Telephone survey data were obtained from patients after participation in a case series study of 124 patients with mild to moderate psoriasis treated with 308-nm UVB laser treatment for a target plaque and other lesions. The survey included information on changes in the target plaque, remission time, changes in other areas of psoriasis, satisfaction with the result, side effects of treatment, and efficacy relative to other treatments. RESULTS: Patients (55% of total) reported overall satisfaction with the treatments, and 63% of patients thought they needed additional laser treatments, including for maintenance. Subjects (25%) reported that the laser treatments were better than any other treatment they had tried. Adverse effects were mild and had either disappeared or were significantly decreased in 86% of patients. Self reported length of remission compared favorably to those for other therapies for localized disease. CONCLUSIONS: UVB laser treatments provide a well-tolerated means to clear psoriasis plaques. The treatment provides a high level of patient satisfaction.     

308nm准分子激光治疗眼眶白癜风的疗效观察

目的：评价308nm准分子激光治疗眼眶白癜风的疗效及安全性。方法：采用308nm准分子激光系统治疗83例眼眶稳定期白癜风患者,每周治疗2次,连续治疗10～30次,治疗1.5～3个月后进行疗效评价。结果：治疗10次、20次及30次后眼眶的显效率分别为54.17%、60.6%、88.46%。结论：308nm准分子激光治疗眼眶白癜风是安全有效的。     

Characteristics of 308 nm excimer laser activated arterial tissue photoemission under ablative and non-ablative conditions

The present study was designed to assess the characteristics of tissue photoemission obtained from normal and atherosclerotic segments of human postmortem femoral arteries by 308 nm excimer laser irradiation of 60 ns pulsewidth. Three ablative (20, 30, and 40 mJ/pulse) and three non-ablative (2.5, 5, and 10 mJ/pulse) energy fluences were employed. Both the activating laser pulses and the induced photoemission were guided simultaneously over one and the same 1,000 micron core optical fiber that was positioned in direct tissue contact perpendicular to the vascular surface. The spectral lineshape of normal arterial and noncalcified atherosclerotic structures was characterized by a broad-continuum, double-peak emission of relevant intensity between wavelengths of 360 and 500 nm, with the most prominent emission in the range of 400-415 (407 nm peak) and 430-445 nm (437 nm peak). Fibrous and lipid atherosclerotic lesions, however, exhibited a significantly reduced intensity at 437 nm compared to normal artery layers (P less than 0.001), expressed as a 407/437 nm ratio of 1.321 +/- 0.075 for fibrous and 1.392 +/- 0.104 for lipid lesions. Normal artery components presented with approximately equal intensity at both emission peaks (407/437 nm ratio: intima, 1.054 +/- 0.033; media, 1.024 +/- 0.019; adventitia, 0.976 +/- 0.021). Comparison of spectral lineshape obtained under various energy fluences within a group of noncalcified tissues disclosed no substantial difference using the 407/437 nm ratio (P greater than 0.05). In contrast, calcified lesions revealed high-intensity multiple-line (397, 442, 461, and 528 nm) emission spectra under ablative energy fluences, whereas a low-intensity broad-continuum, single-peak spectrum resulted from irradiation beyond the ablation threshold. Thus, these findings suggest fluorescence phenomena for broad-continuum spectra, and plasma emission for multiple-line spectra as an underlying photodynamic process. Regardless of the activating energy fluence, spectral analysis of 308 nm activated photoemission provides accurate information about the laser target under standardized in vitro conditions. It is demonstrated that direct contact ablation and simultaneous spectral imaging of the target tissue via the same optical fiber is feasible.(ABSTRACT TRUNCATED AT 400 WORDS)     

他克莫司软膏联合308nm准分子激光治疗儿童局限性白癜风

目的:本研究旨在评价0.03%他克莫司软膏和308 nm准分子激光治疗儿童局限性白癜风的安全性和有效性。同时研究308nm准分子激光联合外用0.03%他克莫司软膏对疗效的影响。方法:76个患者入组研究,研究采用随机单盲自身对照试验共15周。入组患者均具有两侧对称病变,进行左/右面部、躯干、手足的比较。按患者2至4个靶病变随机分为两组:A组患者外用0.03%他克莫司软膏,每天两次;B组患者外用0.03%他克莫司软膏每日两次,联合308nm准分子激光治疗,每周两次。研究期间对疗效和安全性因素进行评价。结果:76个患者完成了研究,A组91.3%和B组97.4%的皮损观察到复色。与治疗前相比,A组和B组皮损均明显改善。B组72.3%的皮损获得4级复色,与A组比较有显着性差异(P<0.05)。面颈部的复色率(复色75%以上)明显高于躯干、四肢、手足的复色率(P<0.05)。两组患者未见明显的副作用,两组之间的副作用发生率没有显著差异。结论:0.03%的他克莫司软膏和308 nm准分子激光对于治疗儿童局限性白癜风是安全、有效的,且耐受性良好。联合使用他克莫司软膏和308nm准分子激光显著提高疗效。     

308nm准分子激光联合驱虫斑鸠菊肌注治疗白癜风临床观察

目的：观察308nm准分子激光联合驱虫斑鸠菊治疗白癜风的疗效及安全性。方法：将98例白癜风患者随机分为三组,其中对照组31例,治疗A组34例,治疗B组33例。对照组：应用驱虫斑鸠菊注射液2ml肌注,每日一次（早晨8点）;治疗A组：应用308nm准分子激光治疗,2～3次/周;治疗B组：采用308nm准分子激光联合驱虫斑鸠菊治疗。三组疗程均为2个月,由专人评价并记录治疗效果及治疗期间出现的不良反应。结果：①治疗B组总有效率为84.8%,明显高于其他两组（P＜0.01）;②治疗B组面颈部有效率为84.1%,躯干四肢为66.7%;均高于其他两组（P＜0.01）,且以面颈部有效率最高;③三组中肢端关节部位的有效率最低,且组间比较无显著性差异（P＞0.05）。结论：应用308nm准分子激光联合驱虫斑鸠菊治疗局限型的非肢端及非关节突出部位的白癜风,能获得满意疗效,可在临床推广应用。     

308nm准分子激光联合哈西奈德溶液治疗头皮银屑病的疗效观察

目的：探讨308nm准分子激光治疗头皮银屑病的临床疗效。方法：将80例头皮银屑病患者分为两组：治疗组40例,给予308nm准分子激光照射治疗,2次／周,期间外用哈西奈德溶液,2次／天;对照组40例,外用哈西奈德溶液,2次／天。两组均治疗4周后观察疗效。结果：治疗组与对照组总有效率分别为97．5％和70％,两组比较有显著性差异（r=11．11,P〈0．01）。结论：308nm准分子激光联合哈西奈德溶液治疗头皮银屑病疗效确切,不良反应少。     

Excimer laser (308 nm) recanalisation of in-stent restenosis: thermal considerations

. Excimer laser recanalisation of in-stent restenosis may be a viable modality for improving coronary patency. However, the presence of arterial stents modifies the thermal properties of the irradiated area and may alter temperature patterns generated during ablation. The goal of this study was to evaluate, in vitro, temperature changes during excimer laser ablation of stented vessels and compare them with those obtained from unstented (control) vessels. Six different stent types (AVE Microstent-II, AVE-GFX, ACS Multi-link, JJ Palmaz-Schatz, JJ Crown, and NIR) were deployed in freshly excised porcine coronary vessels. Three control unstented samples were also measured. Blood or saline was infused through the vessels, while the tissue environment was kept at ∼37°C. A 308 nm excimer laser (Spectranetics, CVX300) with an eccentric 2.0 mm laser catheter (Spectranetics, EII) delivered two trains of 200 pulses each, 10 s apart, at 60 mJ/mm², and 40 Hz, simulating maximum clinical exposure. The catheter was positioned midway in the stent, first coaxially parallel to the vessel wall, and then at an angle against the stent and vessel wall. Temperature measurements (n=168 for blood, n=96 for saline) were performed with a ∼210 μm diameter, fast-response thermocouple with 0.1°C resolution. The probe was positioned to within ∼250 μm from the inner surface of the vessels. Tissue temperature was measured at the catheter tip and at the distal and proximal edges of the stents. Maximum recorded temperatures for coaxial and angular alignment, did not exceed 42.2°C (∼6°C above baseline) and 54.2°C (∼18.1°C above baseline) respectively, for all stents types tested, controls, and all probe locations. Both stented and unstented vessels exhibited comparable temperature gradients. The observed maximum temperatures, obtained under extreme lasing conditions, indicated that 308 nm ablation, in the presence of stents under blood or saline infusion, produces clinically acceptable temperatures.     

308nm准分子激光联合他卡西醇软膏治疗儿童面部白癜风疗效观察

目的:探讨308nm准分子激光联合他卡西醇软膏治疗儿童面部白癜风的疗效。方法:治疗组儿童面部白癜风患者采用Xt rac颠峰准分子激光联合他卡西醇软膏治疗,对照组仅用Xt rac颠峰准分子激光,为期3月,治疗结束后3天进行疗效评价。结果:治疗组显效率77.3%,对照组显效率52.5%,两组差异有统计学意义(χ2=5.69,P<0.05)。结论:308nm准分子激光联合他卡西醇软膏治疗儿童面部白癜风疗效好、副作用小。     

308准分子光联合点阵CO2激光对难治性白癜风的治疗效果

目的 探析308 nm准分子光联合点阵CO2激光在难治性白癜风中的效果。方法 选取我院2022年 4月-2023年9月收治的难治性白癜风患者78例,采用随机抽样法分为参照组和结合组,各39例。参照组应 用308 nm准分子光治疗,结合组应用308 nm准分子光联合点阵CO2激光治疗。比较两组白斑面积、血清抗 酪氨酸酶抗体水平、氧化应激指标、临床疗效及不良反应发生率。结果 结合组治疗后白斑面积小于参照 组（P ＜0.05）;结合组治疗后血清抗酪氨酸酶抗体、丙二醇水平低于参照组,超氧化物歧化酶水平高于 参照组（P＜0.05）;结合组治疗总有效率为97.44%,高于参照组的82.05%（P＜0.05）;结合组不良反应发 生率为5.13%,低于参照组的15.38%,但差异无统计学意义（P ＞0.05）。结论 308 nm准分子光联合点阵 CO2激光可缩小难治性白癜风患者白斑面积,降低其血清抗酪氨酸酶抗体水平,改善氧化应激指标,且治 疗安全性较高。     

Excimer laser ablation for valvular angioplasty in pulmonary atresia and intact ventricular septum

BACKGROUND AND OBJECTIVES: The prognosis for infants with pulmonary atresia and intact ventricular septum (PA/IVS) is poor and they present a major management challenge. Mechanical penetration of the atretic pulmonary valve is an applicable option for decompression of the right ventricle and optimization of left ventricular function. The utilization of laser energy for debulking and vaporization of the atretic valve tissue is a relevant approach due to the potential for controlled, precise mode of energy distribution. STUDY DESIGN/PATIENTS AND METHODS: A 4-month-old female with PA/IVS whose failure to thrive was accompanied by critical hemodynamic abnormalities received successful percutaneous pulmonary valve plate ablation by a 0.9 mm pulsed-wave ultraviolet excimer laser catheter (308 nm wavelength, fluence 50 mJ/mm(2); 30 Hz). A "step-by-step" lasing technique was applied whereby the tip of the emitting laser catheter is advanced ahead of a guide wire that serves mainly as support for positioning of that catheter. RESULTS: Adequate penetration of the atretic tissue enabled introduction of balloon dilations resulting in patency of the atretic valve, decompression of the right ventricle, improved right and left ventricular hemodynamics, and oxygenation. To further investigate the effect of excimer laser energy on atretic valvular tissue this laser was applied in a specimen of heart from an infant who died because of PA/IVS. Histopathologic examination of the irradiated tissue revealed no laser-induced injury to the pulmonary valve. CONCLUSIONS: Thus, laser ablation and penetration of an atretic pulmonary valve is feasible and safe. The penetration of the atretic valve with the laser catheter enables subsequent introduction of various sizes balloon dilations. The application of available laser sources for treatment of congenital heart diseases is reviewed.     

Photoacoustic injury and bone healing following 193nm excimer laser ablation.

The argon-fluoride excimer laser was investigated as a cutting-ablating tool for bone surgery. A total of 52 rats were divided into two experimental groups and two control groups. In one experimental group cortical bone defects were made; in another experimental group defects penetrating into the medullary space were performed. In the two control groups similar defects were achieved using water-cooled carbide burs. The rats were sacrificed on each of the 3, 7, 10, 20, 30, and 40 postoperative day. The cortical bone, the medullary space, and the extrabony tissue were examined by means of light microscopy. In both experimental groups, bone damage, represented by osteocyte destruction, extended to 1,050-1,450 microns ahead from the irradiated site, and bone healing was very much impaired. In the control groups no histological changes could be identified and bone healing appeared to be within normal limits. We believe this extensive bone damage, following 193 nm irradiation, to be a result of photoacoustic waves propagating in the bone following each pulse. In view of our results we feel that excimer lasers presently in use are not suitable for bone surgery. This problem of photoacoustic damage can be overcome in one of two ways: by designing a CW excimer laser or by reducing the pulse width to the picosecond regime.     

他克莫司软膏联合308nm准分子激光治疗白癜风临床观察

目的:探讨外用0.1%他克莫司软膏联合308nm准分子激光治疗白癜风的疗效及安全性。方法:患者35例,以自身未治疗皮损作为空白对照,每例患者选择两处相近或对称部位的皮损,每周2次以308nm准分子激光进行治疗,共治疗16次。A组皮损同时每天早晚外用0.1%他克莫司软膏,B组单用308nm准分子激光治疗,试验结束时依据治疗前、后皮损的照片进行疗效评价。结果:试验结束时,未治疗的皮损均未出现任何改善,A组有效率为97.1%(34/35),B组为85.7%(30/35),显效率A组为74.3(&/35)、B组为48.6%(17/35),两组间显效率有显著性差(异2χ=4.884,P=0.023),但有效率差异不显著(2χ=2.917,P=0.088)。对18例患者进行随访,3个月内,A组所有治疗皮损均维持稳定或持续好转,而B组有3例皮损出现复发。结论:308nm准分子激光治疗白癜风疗效高、副作用少,联合外用0.1%他克莫司软膏可显著提高其疗效并减少复发。     

Excimer laser irradiation of non-calcified and calcified human atheroma (248 and 308nm wavelengths)

In order to develop a system of peripheral arterial angioplasty, we carried out an in vitro study to define the quantitative, thermal and morphological characteristics of human-atheroma ablation by excimer laser. A multigas ‘Sopra’ laser was used. The study was performed by using 248nm, krypton fluoride (KrF), then 308nm, xenon chloride (XeCl) wavelengths. The delivered energy was up to 150 mJ pulse⁻¹, pulse duration was 25ns, and the repetition rate could be adjusted to up to 20Hz. Irradiated tissue segments of the superficial femoral and external iliac arteries were obtained in man during surgical procedures and were both calcified and non-calcified atherosclerotic lesions. Quantitative measurements showed a linear increase of ablated tissue mass depending on the energy delivered. For the same energy, the loss of mass was greater with the 248nm wavelength than with the 308nm. The maximum temperature rise measured at the site of irradiation was 6°C at 248nm and 25°C at 308nm. Histological analysis of the irradiated segments revealed neat and precise ablation without thermal injury of adjacent tissue. At 248nm, this phenomenon was observed for calcified as well as non-calcified atheromas. It is concluded that quantitative, thermal and morphological characteristics of in vitro ablation of calcified and non-calcified human atheroma by excimer laser are compatible to clinical requirements. The results observed at 248nm were experimentally more satisfactory.