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PubMed1990

Application of erbium: YAG laser in ocular ablation.

Recent developments in lasers have provided us the possibility of laser ocular surgery. The xenon, argon, neodymium:YAG and dye lasers have been successfully used in out-patient clinics. The excimer laser has been attracting researchers' interest in the new application of laser to cornea and lens. The erbium:YAG laser emits a 2.94-microns beam that can ablate the transparent ocular tissues such as lenses and corneas. The author has applied this laser to the cornea, lens, vitreous and other ocular tissues. The erbium:YAG laser beam was directed through a 1.5-meter-long, 200-microns-diameter fiberoptic guide. The radiant energy measured about 50 mJ at the end of the probe. The laser was emitted as a 400-microsecond pulse. Freshly enucleated rabbit eyes were used in this study. Laser burns were applied to the tissue surface at various energy settings. At minimal power, the tissues were coagulated by the erbium:YAG laser application. At a power of more than 636-954 mJ/mm2, tissue began to evaporate; the tissue loss was observed under a surgical light microscope. Corneal photoablation, lens ablation, iridotomy, trabeculotomy, cutting of the vitreous and retinal ablation were easily performed. Like the excimer laser, the erbium:YAG laser is a potential tool for ocular surgery.

Animals↗
PubMed1988

Erbium filtration for dose reduction in dental radiography.

Previous work has suggested that rare-earth filtration of diagnostic X rays is an effective means of dose reduction in radiology. Erbium (atomic number 68) is particularly promising in this respect. The effects on the X-ray beam and surface dose of the addition of 0.1 mm of erbium foil to the conventional filtration of a GE1000 dental X-ray set were investigated. Filtration by 0.1 mm of erbium produced a beam of narrower spectrum, greater penetration but lower intensity than that filtered conventionally by aluminium alone. The overall dose reduction achieved in dental radiography was greater than 30% between 65 and 85 kVp with a maximum dose reduction of 42% at 65 kVp. The question of the cost-effectiveness of erbium filtration as a radiation protection measure is also addressed.

Erbium↗
PubMed1990

Comparison of the erbium-yttrium aluminum garnet and carbon dioxide lasers for in vitro bone and cartilage ablation.

The in vitro bone- and cartilage-ablation characteristics of the solid-state erbium:yttrium aluminum garnet laser were compared to those of the carbon dioxide laser. Ablations of fresh, frozen cadaver septal cartilage and maxillary sinus bone were performed using total energies between 1 and 6 J. Specimens were studied using hematoxylin and eosin stain and digitized, computer-assisted measurements of 35-mm photographs. Erbium-yttrium aluminum garnet-ablated bone averaged 5 microns of adjacent tissue thermal injury, compared with 67 microns with carbon dioxide-ablated bone. Erbium-yttrium aluminum garnet-ablated cartilage averaged 2 microns of adjacent tissue thermal injury, compared with 21 microns with the carbon dioxide-ablated cartilage. The tissue-ablation characteristics of the erbium-yttrium aluminum garnet laser are promising for future otolaryngologic applications.

Aluminum↗
PubMed1977

[Synoviorthesis of finger joints using erbium-169. Parameters influencing the clinical results at middle-term].

Synoviorthesis of the finger joint with erbium-169 is a beneficial therapeutic procedure which produces reduction of articular pain and swelling in 2/3 of cases. The effect is lasting and shows only slight regression during the first 24 months. However, if the rheumatoid disease is very active, or if the articular lesions are primarily erosive, the results are poorer. No correlation was found between therapeutic results and the radiological findings prior to 169E treatment. Erbium-169 reduces inflammation and leads to progressive articular fibrosis. Any chronic synovitis of interdigital joints resistant to appropriate conventional anti-inflammatory treatment may benefit from radio-synoviorthesis with erbium-169. Erbium-169 synoviorthesis is is technically easy to perform and free of side effects. It is a palliative measure which the authors consider a valuable complement to the classical treatment of rheumatoid arthritis.

Aged↗
PubMed1996

Pulsed Erbium:YAG laser ablation in cutaneous surgery.

BACKGROUND AND OBJECTIVE: Among the various pulsed midinfrared-lasers studied in skin surgery the 2.94 microns Erbium:YAG laser has been shown to combine most efficacious ablation with least thermal damage due to its unique absorption characteristics in tissue water. A newly developed high-power Erbium:YAG laboratory laser providing output energies (up to 1.5 J/pulse) and repetition rates (up to 15 Hz) appropriate for clinical use enabled us to investigate its potential indications in dermatological surgery. STUDY DESIGN/MATERIALS AND METHODS: Erbium:YAG laser ablation was performed in vitro on pig skin and in vivo on a total of 30 patients presenting with different skin disorders. RESULTS: In vitro ablation efficiency linearly increased with radiant exposure and was inversely correlated with pulse frequency. Ablation rate at 10 Jcm-2 (used clinically) measured from approximately 10 microns (at 10 Hz) to 40 microns (at 1 Hz). Also for high repetition rates thermal necrosis did not exceed 50 microns, corresponding clinically to capillary bleeding after exposure of the dermis. Superficial lesions, such as epidermal nevi, were easily ablated and re-epithelization was unimpaired owing to the absence of tissue necrosis. In tattoos, exposed pigment particles were precisely removed. However, in deeper lesions the casual onset of bleeding impeded the procedure and scar formation was observed after reepithelization. CONCLUSION: Pulsed 2.94 microns Erbium:YAG laser surgery allows an extremely precise etching of delicate superficial skin lesions and also should have a potential for skin resurfacing.

Animals↗
PubMed1999

Periorbital skin resurfacing using high energy erbium:YAG laser: results in 50 patients.

OBJECTIVE: To evaluate Erbium:YAG regional periorbital laser resurfacing clinically and histologically. STUDY DESIGN/MATERIALS AND METHODS: Photographic evaluation before and after Erbium:YAG resurfacing with histologic evaluation of depth of injury. SETTING: Group private single specialty practice. PATIENTS: Fifty patients in the age range of 35-62 years, Fitzpatrick skin types I-III were treated using Erbium:YAG for regional resurfacing of periorbital rhytides. OUTCOME MEASURES: Patients were seen at days 1, 2, 3, 7, 14, 28, and at six months and one year. Photographs were obtained prior to application of topical anesthesia and were utilized to judge improvement of rhytides at all time intervals. Additional photographs were taken at each follow-up visit and the results judged by an independent investigator. Results were graded into five categories at all treatment intervals: no improvement, mild (grade 1: up to 25%), moderate (grade 2: 25-50%), good (grade 3: 50-75%, or excellent (grade 4: 75-100%). For histologic evaluation of depth of ablation and thermal injury one, two, and three passes at 21.2 J/cm2 were performed on four patients. RESULTS: Re-epithelization in the periorbital region was rapid with a mean duration of 2.65 days. Erythema ranged from a longest of six weeks to the shortest of seven days with a mean duration of 15.4 days. Evaluation of clinical results revealed that at two weeks mean improvement was 2.15 (between moderate and good). At four weeks further improvement was noted with a mean of 2.62. By six months, mean improvement score increased to 2.94. Minimal further improvement was noted between six months and one year with a mean improvement score of 3.02 (good to excellent). Histology revealed complete removal of the epidermis with one to three passes. Dermal ablation of 5-10 microns accompanied by small increases (5-10 microns) in dermal thermal injury occurred with each subsequent pass. CONCLUSIONS: We conclude that high energy Erbium:YAG periorbital resurfacing is a safe and effective modality which achieves substantial therapeutic effect. Most patients achieve approximately 75% improvement. Erythema fades quickly, reepithelization is rapid and side effects are minimal.

Adult↗
PubMed1998

[Treatment of peri-ocular skin lesions with the erbium:YAG laser].

INTRODUCTION: A great number of consmetically disturbing, cutaneous lesions are localized in the periocular region. While various approaches for treatment such as excision, electrocauterization or cryosurgery often show unsatisfactory results, the use of laser technology is of increasing interest. MATERIAL AND METHODS: A total of 104 patients with different cutaneous periorbital lesions (wrinkles, xanthelasma, syringoma) were treated with a new erbium: YAG laser system (wavelength 2940 nm, pulse duration 0.350 ms and pulse energy 0.1-1.7 Joules), which works on the principle of vaporization. RESULTS: The erbium: YAG laser allows athermic ablation of very thin skin layers without scarring and with minimal lateral thermal injury due an extremely short pulse duration. Periorbital lesions can be treated effectively by erbium: YAG laser, and good to excellent cosmetic results can be obtained. CONCLUSIONS: The use of pulsed erbium: YAG laser is an effective and promising new method for treatment of different superficial periorbital cutaneous lesions.

Adult↗
PubMed2001

[Phacoemulsification and vitrectomy with the erbium:YAG laser and phacoemulsification with the neodymium:YAG laser].

There are an increasing number of possible applications for the use of Erbium:YAG and Neodymium:YAG lasers in ophthalmology. Laser-phacoemulsification as well as Erbium-laser vitrectomy is of major interest. We report on the underlying technology and more than 1-year-experience using the PHACOLASE (Asclepion-Meditec, Jena, Germany, 10-100 Hz frequency, 5-50 mJ single pulse energy) for phacoemulsification and pars plana vitrectomy and the Lyla-Dodick laser photolysis (A.R.C. Laser, Eckental-Forth, Germany, 1-20 Hz, up to 8 mJ single pulse energy). The Erbium:YAG-laser as well as the Neodymium:YAG-laser enabled us to extract lenses with up to medium hard nuclei. Moreover, the Erbium laser enabled fast vitrectomy with little mechanical traction. In many of our initial surgical operations we had to change to mechanical vitrectomy due to initial technical problems. No new complications occurred intra- or postoperatively. The handpiece worked well in removing vitreous bodies, but was not feasible for cutting membranes. Modified handpieces for this purpose are under development.

Equipment Design↗
PubMed2000

Erbium:YAG laser vitrectomy: clinical results.

PURPOSE: To evaluate the intraoperative use of a new erbium:yttrium aluminum garnet (YAG) laser vitrectomy system. METHODS: An erbium:YAG laser combined with an infusion-suction system (Wavelight Laser Technology, Erlangen, Germany), equipped with a flexible fiber optic and a hand piece with a 20-gauge end tip and a side opening of 0.6 mm was used. Cutting rates were 2 to 30 Hz, and energies were 20 to 40 mJ. Between January 1998 and January 1999 the erbium:YAG laser system was used in 67 consecutive patients (68 eyes) where vitrectomy was indicated. The patients had a complete eye examination before surgery and postoperatively at 1 to 3 days, 1 week, 3 weeks, and 6 weeks. During surgery, the total time needed for vitrectomy, the laser time itself, amount of energy used, cutting rate, suction, and perfusion, as well as manipulative difficulties and/or complications, were documented. RESULTS: The average laser time was 4.5 minutes for a basic vitrectomy with a setting of 20 mJ, 20 Hz, and suction 100 to 200 mm Hg. Hemorrhages, loose intravitreal, and preretinal membranes of different densities were cut well with adjustment of energy. After a minimal observation time of 6 months (median, 12.7 months) no laser-associated complications were found. CONCLUSIONS: The erbium:YAG laser, combined with an infusion-suction system, offers a new technology for vitreous surgery. Its advantages, compared with mechanical vitrectomy cutters, are higher cutting rates and the modulation of energy. Modifications of the end tip are needed to develop this system further.

Adolescent↗
PubMed2000

Pilot study on erbium laser phacoemulsification.

PURPOSE: To investigate the suitability of erbium laser phacoemulsification for cataract surgery using a prospective pilot study. DESIGN: Prospective, single-center, nonrandomized clinical trial. PATIENTS AND METHODS: Slit-lamp microscopy, keratometry, best-corrected visual acuity, refraction, pachymetric corneal thickness, endothelial cell density, and intraocular pressure were assessed before surgery and on the first, fourth, fourteenth, and the sixtieth day after surgery in 40 eyes of 34 patients with senile cataract (17 males with a mean age of 67.3 years; 17 females with a mean age of 73.2 years). All operations were performed by one surgeon (HH) using the MCL-29 erbium laser (Aesculap-Meditec, Jena, Germany). The nuclear sclerosis grade ranged from 0 to 4. MAIN OUTCOME MEASURES: Primary outcome measures were defined as the ability to emulsify the lens nucleus under clinical conditions and the occurrence of side effects. Secondary outcome measures included the change in visual acuity, refraction, intraocular pressure, corneal thickness, and endothelial cell density. RESULTS: Complete emulsification of the lens nucleus using the erbium laser was achieved in 36 of 40 eyes (90%; nuclear sclerosis grade, 0-3). Partial emulsification of the nucleus was possible in two cases with grade 3 nuclear sclerosis, in one case of grade 2 nuclear sclerosis, and in one case of cataract with grade 4 nuclear sclerosis. Mean phacoemulsification time was 3 minutes, and the total applied energy equaled 38.5 J. The postoperative changes in visual acuity, spherical and astigmatic refraction, and intraocular pressure were found to be the same as with ultrasonic phacoemulsification. The decrease in the density of endothelial cells (by 0.96%) was not statistically significant. Posterior capsule ruptures occurred in three eyes early in the series. There were no further vision-threatening complications. CONCLUSIONS: Erbium laser phacoemulsification is effective for lenses with mild to moderate nuclear sclerosis. For higher grades of nuclear sclerosis, further improvements in technical and surgery-related parameters are required.

Aged↗
PubMed2001

Transdermal drug delivery enhanced and controlled by erbium:YAG laser: a comparative study of lipophilic and hydrophilic drugs.

The influence of an erbium:YAG laser on the transdermal delivery of drugs across skin was studied in vitro. Indomethacin and nalbuphine, which have the same molecular weight, were selected as model lipophilic and hydrophilic drugs, respectively, to compare skin permeation by laser treatment. The results indicate a significant increase in the permeation of indomethacin and nalbuphine across skin pretreated with an erbium:YAG laser. The laser had a greater effect on the permeation of hydrophilic molecules which usually possess low permeability. The laser intensity and its spot size were found to play an important role in controlling transdermal delivery of drugs. Permeation of the hydrophilic drug increased following an increase of laser energy. On the other hand, a different result was observed for the lipophilic drug transported across laser-treated skin. The stratum corneum (SC) layer in skin could be partly ablated by the erbium:YAG laser. The barrier function of the SC may also be modulated by a lower intensity of the laser without affecting the viability and structure of the epidermis/dermis as determined by histological observations. However, ultrastructural alteration of the epidermis/dermis may be caused by laser treatment. Use of an erbium:YAG laser is a good method for enhancing transdermal absorption of both lipophilic and hydrophilic drugs, because it allows precise control of SC removal, and this ablation of SC can be reversible to the original normal status.

Administration, Cutaneous↗
PubMed2006

Long-term results of Erbium YAG-laser-assisted deep sclerectomy.

PURPOSE: To evaluate the long-term results of Erbium YAG-laser-assisted deep sclerectomy (DS). In this procedure, the delicate dissection of a deep corneoscleral lamella is greatly simplified by using the Erbium YAG-laser. METHODS: Data of 14 consecutive patients (10 male, four female, age 67.7+/-10.4 years), who underwent surgery from 1999 to 2000 were analysed retrospectively. The procedure was begun as a standard DS. The deep corneoscleral lamella was dissected with a pulsed Erbium YAG-laser (energy: 40-100 mJ, frequency: 5-10 Hz). Schlemm's canal was unroofed and the lamella thinned until aqueous percolated continuously through the membrane. RESULTS: The mean follow-up time was 50.4+/-6.8 months. The mean preoperative intraocular pressure (IOP) was 37.7+/-10.5 mmHg. The mean postoperative IOP was 16.1+/-3.9 mmHg at 1 month, 15.1+/-4.3 mmHg at 3 months, 16.4+/-4.5 mmHg at 12 months, and 17.6+/-8.7 mmHg at 50.5 months. The complete success rates (IOP< or =21 mmHg+IOP reduction > or =20% without glaucoma medication) were 83.3% at 3 months and 50% at 12 and 50.5 months. Rates for qualified success (IOP< or =21 mmHg+IOP reduction > or =20% with glaucoma medication) were 91.7% at 3 months, 92.9% at 12 months, and 78.6% at 50.5 months. The number of glaucoma medications was reduced from 3.07+/-0.92 preoperatively to 1.14+/-1.41 at 50.5 months. A single case of anterior-chamber penetration, requiring iridectomy, was the only intraoperative complication. CONCLUSIONS: Erbium YAG-laser-assisted DS has the advantage of a greatly simplified dissection, while offering a successful long-term IOP control comparable to conventional DS.

Adult↗
PubMed2004

Effect of the erbium dopant architecture on the femtosecond relaxation dynamics of silicon nanocrystals.

Femtosecond pump-probe absorption spectroscopy is used to investigate the role of Er(3+) dopants in the early relaxation pathways of photoexcited Si nanocrystals. The fate of photoexcited electrons in three different Si nanostructures was studied and correlated with the effect of Er-doping and the nature of the dopant architecture. In Si nanocrystals without Er(3+) dopant, a trapping component was identified to be a major electron relaxation mechanism. Addition of Er(3+) ions into the core or surface shell of the nanocrystals was found to open up additional nonradiative relaxation pathways, which is attributed to Er-induced trap states in the Si host. Analysis of the photodynamics of the Si nanocrystal samples reveals an electron trapping mechanism involving trap-to-trap hopping in the doped nanocrystals, whereby the density of deep traps seem to increase with the presence of erbium. To gain additional insights on the relative depths of the trapping sites on the investigated nanostructures, benzoquinone was used as a surface adsorbed electron acceptor to facilitate photoinduced electron transfer across the nanocrystal surface and subsequently assist in back electron transfer. The established reduction potential (-0.45 V versus SCE) of the electron acceptor helped reveal that the erbium-doped nanocrystal samples have deeper trapping sites than the undoped Si. Furthermore, the measurements indicate that internally Er-doped Si have relatively deeper trapping sites than the erbium surface-enriched nanocrystals. The electron-shuttling experiment also reveals that the back electron transfer seems not to recover completely to the ground state in the doped Si nanocrystals, which is explained by a mechanism whereby the electrons are captured by deep trapping sites induced by erbium addition in the Si lattice.

Journal Article↗
PubMed2005

Influence of the short-range coordination order of erbium ions on excitation migration and upconversion in multicomponent glasses.

Applying a pair-correlation function of erbium ions that is known from x-ray absorption fine structure spectroscopy, we develop a new statistical model of migration-assisted upconversion in erbium-doped glasses. The results of modeling show that short-range coordination order of erbium ions contributes to the upconversion rate for both low and high population inversion. In addition, we report the methods of suppression of the short-range order of erbium ions in multicomponent glasses.

Journal Article↗
PubMed2003

Laser flap delay: comparison of Erbium:YAG and CO2 lasers.

The delay phenomenon has long been recognized as a powerful tool in reconstructive surgery. This phenomenon involves creating alterations in skin flap blood supply or microcirculation to increase the size of the surviving flap. In the past many reconstructive surgeons depended on surgical delay as an integral part of their surgical planning. Today surgical delay remains a reliable method for maximizing flap survival. Although surgical delay remains the gold standard many have searched for methods to create the same effect with less morbidity and reduced cost. The purpose of this study was to determine whether near-scarless delay can be performed with either the Erbium:YAG or CO2 laser using a standard McFarlane skin flap model. Four groups were identified. Surgical delay, Erbium laser delay, and CO2 laser delay groups were each compared with a nondelayed control. Each group consisted of ten Sprague-Dawley rats. On Day 0 all delay procedures were performed on the lateral periphery of the outlined dorsal skin flaps. Interruption of this lateral blood supply was accomplished by two parallel 10-cm incisions in the surgical delay group. Likewise blood supply and microcirculatory alterations were accomplished in the laser delay groups by two parallel 10-cm laser treatments. On Day 7 a 10 x 4-cm cranially based dorsal skin flap was elevated. On Day 14 flap survival was analyzed by calculating percentage flap survival. The Erbium:YAG laser delay of the McFarlane flaps resulted in an average of 32 per cent less flap loss compared with controls (P = 0.0001). The CO2 laser resulted in an average of 36 per cent less flap loss compared with controls (P = 0.0002), whereas the surgical delay group had a 23 per cent smaller flap loss (P = 0.009). There was no significant difference between any of the delay groups. These results indicated that CO2 and Erbium:YAG lasers are as effective as surgery for delay of skin flaps in the rat model. They may provide an effective and inexpensive method for near-scarless skin flap delay in humans.

Animals↗
PubMed1998

Erbium:YAG laser-assisted cataract surgery.

BACKGROUND AND OBJECTIVE: To assess the safety and efficacy of erbium:YAG laser-assisted cataract removal. PATIENTS AND METHODS: A total of 15 patients underwent cataractous lens removal. All the patients had a visual acuity of 20/50 or worse secondary to senile cataract. The endothelial cell count was calculated preoperatively and at 6 weeks postoperatively. A 2.94-micron-wavelength erbium: YAG laser with a zirconium-fluoride fiber optic and silica tip was used to fracture and emulsify the nucleus. The erbium:YAG laser was chosen due to its high absorption in water, a primary component of a cataractous lens. RESULTS: The postoperative visual acuity was 20/30 or better in all the eyes that were treated with surgery. The endothelial cell loss at 3 months was 0% to 10%. No laser-related complications were noted. A conversion to an ultrasound surgical technique was utilized in six cases. Vitreous loss occurred in one case due to the posterior extension of an anterior capsulotomy tear. CONCLUSION: This study demonstrated the ability of an erbium:YAG laser system to safely and effectively emulsify the lens nucleus. Laser-assisted cataract surgery is a promising new clinical procedure.

Aged↗
PubMed1998

Experimental ocular surgery with a high-repetition-rate erbium:YAG laser.

PURPOSE: To evaluate the performance in ocular surgery and the ocular tissue interactions resulting from increasing the maximum repetition rate of a pulsed-mode erbium:YAG laser system from 30 to 200 pulses per second. METHODS: An erbium:YAG laser was used that emitted at 2.94 microm with an output graduated from 0.2 mJ to 25 mJ and a repetition rate from 2 Hz to 200 Hz and that was equipped with a flexible optical fiber attached to various interchangeable 20-gauge endoprobes to perform ocular surgery in enucleated pig eyes. The specific maneuvers were performed in close contact in nontransmitting aqueous media and included inner retinal ablation, retinotomy, lens capsulotomy, lens ablation, iridotomy, and iridectomy. Selected tissue specimens were examined by light microscopy. RESULTS: Increasing the repetition rate to the 200-Hz range significantly improved the smoothness, continuity, and speed of all surgical maneuvers. Compared with the 30-Hz rate, substantially lower energies per pulse were efficient with the 200-Hz rate. The "sticking effect" between the tip of the probe and the target tissue at low-repetition rates, which resulted in discontinuation of the surgical maneuver, particularly during lens surgery, was eliminated with the use of high-repetition rates. Use of high-repetition rates produced a zone of residual thermal damage less than 30 microm in all ocular tissues. The histologic findings of tissue interactions were comparable to those obtained in published studies in which the same wavelength and low hertz rates were used. CONCLUSIONS: The high-repetition-rate erbium:YAG laser technology described is advantageous, compared with low-repetition-rate erbium:YAG lasers, and is applicable in a variety of ocular surgical procedures. Innovations in endoprobe design and further study will determine its role in contemporary ocular surgery.

Animals↗
PubMed1988

Ablation of bone and methacrylate by a prototype mid-infrared erbium:YAG laser.

An erbium:YAG laser was used to generate 200-microseconds pulses of mid-infrared 2.94-microns light in both the single and multimode configurations. Laser pulses were focused on the surfaces of both rabbit long bones and methacrylate blocks, and the tissue response was examined histologically. The depth of thermal injury was determined by ocular micrometry. Over all energy levels tested, the erbium:YAG laser produced ablation of bone and methacrylate with minimal thermal damage to adjacent tissue. Increasing the laser energy per pulse produced increasingly wider and deeper grooves in both bone and methacrylate. However, such increase in laser energy produced a proportionately greater increase in the zone of thermal injury in methacrylate as compared with bone. These studies suggest the feasibility of a surgical erbium:YAG laser in orthopaedics and other forms of ablative surgery.

Animals↗