Epidermal grafting for leukoderma resulting from 1064-nm quality-switched neodymium-doped yttrium aluminium garnet laser toning.

Leukoderma secondary to Q-switched 1064-nm neodymium-doped yttrium aluminium garnet laser is usually refractory to treatment. The pathogenesis was cumulative phototoxic damage to melanocytes and eventually resulted in melanocytopenia. Wood's light or UV imaging can help observe early leukoderma before it becomes apparent clinically and determine the degree of melanocytopenia before conducting a biopsy. NB-UVB phototherapy and 308-nm excimer laser can potentially worsen the pre-existing melasma lesions and may not be effective if the lesions have already become melanocytopenic. Epidermal grafting can replenish the hypopigmented area with melanocytes without worsening melasma.

Genotoxic effects of 1064-nm Nd:YAG and 532-nm KTP lasers on fibroblast cell cultures.

BACKGROUND: Several different laser types are used in cutaneous surgery. The neodymium:yttrium-aluminium-garnet (Nd:YAG) and frequency-doubled Nd:YAG (KTP, potassium titanyl phosphate) lasers are widely used in dermatology. OBJECTIVES: To investigate the possible genotoxic effects on fibroblasts of irradiation with a 1064-nm Nd:YAG laser and a 532-nm KTP laser. METHODS: Fibroblast cell cultures were exposed to each of the lasers, using 10-mm spot size at 60 ms pulse duration with 10, 20, 40 J/cm(2) and 3, 6, 12 J/cm(2) fluences, respectively. Fibroblasts in passages 1-6 were used. During laser irradiation, 96-well microplate cultures were kept on a cooling block and transported on ice and in the dark, and processed immediately for single-cell gel electrophoresis (SCGE) assay (also known as a comet assay). RESULTS: DNA damage was determined by computerized assessment of comet assay. There was increasing damage with increasing numbers of passages. For the Nd:YAG laser, the greatest damage occurred on passages 5 and 6, whereas the greatest damage appeared at passages 3 and 4 for KTP and returned to baseline at passages 5 and 6. Damage also increased with each dose increment for both wavelengths. At the highest dose for both wavelengths (Nd:YAG 40 J/cm(2) and KTP 12 J/cm(2)), damage was higher with the Nd:YAG laser. CONCLUSIONS: Different patterns of cellular damage were seen for different cell-culture passages, treatment doses, and laser wavelengths. These dose ranges are generally used for the treatment of vascular and pigmented lesions and for rejuvenation purposes. As replicative ageing or cell senescence is one of the critical factors determining the extent of cell damage induced by laser therapy, these results may have important implications for clinical practice.

Systematic investigation of metallosis associated with magnetically controlled growing rod implantation for early-onset scoliosis.

AIMS: To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. METHODS: This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining. RESULTS: Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues. CONCLUSION: Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375-1383.

Haptic fracture and dislocation of polyimide intraocular lens after neodymium: YAG laser capsulotomy: A case report.

RATIONALE: We report a case of haptic fracture of polyimide intraocular lens (IOL) and its dislocation after neodymium:YAG (Nd:YAG) laser capsulotomy. To the best of our knowledge, this is the first report of both the fracture and dislocation of the IOL after laser posterior capsulotomy. PATIENT CONCERNS: A 78-year-old male was referred to our clinic with a history of decreased visual acuity after Nd:YAG laser posterior capsulotomy in the right eye. A dislocated IOL was observed on slit lamp examination. DIAGNOSIS: On slit-lamp examination, dislocated IOL with intact anterior capsulorrhexis margin was observed in the right eye. INTERVENTIONS: We removed the dislocated IOL and fixed a 3-piece IOL (Acrysof MN60AC, Alcon Laboratories, Inc) in the ciliary sulcus under retrobulbar anesthesia. OUTCOMES: After the operation, the observed uncorrected distance visual acuity (UCVA) was 20/20 and the measured intraocular pressure (IOP) was 18 mmHg; the IOL was fixed in the ciliary sulcus. LESSONS: Three-piece, silicone-polyimide haptics in IOLs can get fractured after Nd:YAG laser capsulotomy. Thus, it is suggested that sufficient haptic dilation should be ensured while performing Nd:YAG laser capsulotomy in patients with polyimide haptics. Moreover, a small-sized capsulotomy is likely to be helpful in such patients.

Potential interference of small neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators.

BACKGROUND: Magnetic fields may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets, which are small in size but produce strong magnetic fields, have become widely available in recent years. Therefore, NdFeB magnets may be associated with an emerging risk of device interference. OBJECTIVE: We conducted a clinical study to evaluate the potential of small NdFeB magnets to interfere with cardiac pacemakers and ICDs. METHODS: The effect of four NdFeB magnets (two spherical magnets 8 and 10 mm in diameter, a necklace made of 45 spherical magnets, and a magnetic name tag) was tested in forty-one ambulatory patients with a pacemaker and 29 patients with an ICD. The maximum distance at which the magnetic switch of a device was influenced was observed. RESULTS: Magnetic interference was observed in all patients. The maximum distance resulting in device interference was 3 cm. No significant differences were found with respect to device manufacturer and device types. CONCLUSION: Small NdFeB magnets may cause interference with cardiac pacemakers and ICDs. Patients should be cautioned about the interference risk associated with NdFeB magnets during daily life.

Retinal detachment following neodymium-YAG laser capsulotomy.

Five patients developed retinal detachments within one month of undergoing neodymium-YAG laser posterior capsulotomy. In four patients rhegmatogenous retinal detachments developed in association with typical aphakic breaks; in the fifth patient a previously stable extramacular traction detachment extended into the fovea. In all five patients scleral buckling or vitrectomy successfully reattached the retina and visual acuity improved. None of the findings associated with the detachments could be definitely attributed to the YAG laser. These included the lack of structural or positional changes in the vitreous as well as the absence of retinal damage. We were unable to learn the specific settings used for each laser but were told that the minimum energy levels needed to produce a capsulotomy were used.

Fire during the use of Nd-Yag laser.

Fire during the use of Nd-Yag laser is a very rare complication. A case report of laser fire during the use of Nd-Yag laser for congenital subglottic stenosis is reported. The probable causes for the fire, management and short review of literature are dealt with. This case report highlights the importance of following the safety protocol during laser surgery.

Laser eye injuries in military occupations.

INTRODUCTION: Lasers (light amplification by stimulated emission of radiation) play an important role in our world and their use is increasing. They are powerful tools for good, but can also cause tragedy, especially in an aviation environment. Information about injuries associated with lasers is limited. This study highlights several laser eye injuries in the U.S. military and discusses issues pertaining to them. METHODS: We gathered data from the U.S. Army Safety Center, the U.S. Army Center for Health Promotion and Preventive Medicine, and the Walter Reed Army Institute of Research. This paper describes ten representative cases of laser eye injury that occurred in the U.S. military between 1984 and 2000. RESULTS: Patients suffered retinal damage, though no corneal injury occurred. Most were caused by accidental exposure to a Q-switched, Neodynium:YAG (Nd:YAG) laser at 1064 nm wavelength. The incidents occurred both on and off duty, indoors and outdoors, and from close and long ranges. None of the victims were wearing eye protection. Inadequate training and poor equipment design were major factors in at least six of the nine unintentional cases. The tenth occurred during military operations in the Persian Gulf. All of the victims needed several months medical care and follow up. Two received medical discharges as a result of their injuries. DISCUSSION: As illustrated by these cases, human and societal costs from unintentional laser eye injuries can be reduced by improving operator training, safety procedure compliance, and equipment design. In addition, intentional laser eye injuries are a growing concern and further research is needed to design appropriate protection, treatment and countermeasures.

Inactivation of bacteria and yeasts on agar surfaces with high power Nd:YAG laser light.

Near infrared light from a high-powered, 1064 nm, Neodymium:Yttrium Aluminium Garnet (Nd:YAG) laser killed a variety of Gram-positive and Gram-negative bacteria and two yeasts, lawned on nutrient agar plates. A beam (cross-sectional area, 1.65 cm2) of laser light was delivered in 10 J, 8 ms pulses at 10 Hz, in a series of exposure times. For each microbial species, a dose/response curve was obtained of area of inactivation vs energy density (J cm-2). The energy density that gave an inactivation area (IA) equal to 50% of the beam area was designated the IA50-value and was plotted together with its 95% confidence limits. Average IA50-values were all within a threefold range and varied from 1768 J cm-2 for Serratia marcescens to 4489 J cm-2 for vegetative cells of Bacillus stearothermophilus. There were no systematic differences in sensitivity attributable to cell shape, size, pigmentation or Gram reaction. At the lowest energy densities where inactivation was achieved for the majority of organisms (around 2000 J cm-2), no effect was observed on the nutrient agar surface, but as the energy density was increased, a depression in the agar surface was formed, followed by localized melting of the agar.

The relationship of different power settings and fiber geometries to thermal tissue damage created by the superpulse Nd:YAG laser.

We attempted to quantify the amount of thermal damage that was created to surrounding tissues when an incision was made with the superpulse neodymium:yttrium-aluminum-garnet (Nd:YAG) laser with the optical fiber in contact. Light micrographic studies of several incisions, at different laser power settings and with different fiber geometries, were made in the anterior abdominal wall of 16 Sprague-Dawley rats. The specimens were collected immediately postoperatively and at 48 hours postoperatively. Several laser power settings (2-50 W) and seven different optical fiber geometries were studied. The micrographs showed minimal damage (<0.1 mm) to surrounding tissues at all laser power settings in both the immediate and the 48-hour studies. The superpulse Nd:YAG laser with optical fiber contact limited laser thermal damage to the surrounding tissues to less than 0.1 mm in the range of power settings studied. Higher power settings minimally increased the damage. The geometries of the optical fiber created no significant alteration in thermal damage. The results suggest that the superpulse Nd:YAG laser creates both thermal and photodisruptive effects in tissue.