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Laser facial skin resurfacing: discussion on erbium:YAG and CO2 lasers.

There are two lasers for resurfacing. The erbium:YAG laser and the CO2 laser both have different physical and physiologic differences when striking the skin. Therefore, each laser gives a different result. This article reviews the use of the Sharplan Silktouch CO2 laser for 4 years and the erbium:YAG laser for 1 year. In the last year, we have performed 40 laser procedures with the erbium:YAG laser. Discussion ensues regarding the differences and similarities of the two lasers as well as the difficulties and complications.

Carbon Dioxide↗

Use of an erbium laser in lieu of retraction cord: a modern technique.

The two-cord retraction technique is used for troughing around a crown to achieve biologic width. This technique can cause significant discomfort for the patient and offers several potential clinical disadvantages for the dentist, of which unpredictable tissue recession is the most significant. The clinical case presented in this article compares the use of the standard two-cord retraction technique with that of an 2,780 nm erbium-class dental laser to determine which method achieves an accurate, easily readable impression while respecting the biologic width. Using an erbium laser to achieve the trough prior to placing an indirect restoration results in little or no postoperative discomfort for the patient; in addition, the erbium laser reduces intraoperative complications related to tissue recession and patient discomfort while providing consistently accurate impressions.

Adult↗

Clinical and radiological course in apicoectomies with the Erbium:YAG laser.

OBJECTIVE: A study is made of the efficacy of the Erbium:YAG laser in granulomatous periapical lesions, based on clinical and radiographic controls. MATERIAL AND METHODS: The study comprised a series of 45 patients amenable to periapical surgical treatment of incisors, canines and premolars. A conventional surgical technique was used, with silver amalgam retrograde filling and irradiation of the bone defect and remnant root cement with the Erbium:YAG laser. Clinical and radiographic controls were made during 24 months, assessing the absence of symptoms and the presence of pain, swelling or fistula and ossification of the lesions, respectively. RESULTS: The clinical course proved asymptomatic in 95.5% of the cases. As regards remodeling of the bone cavity, 77.7% had completed ossification after 24 months, 13.3% were in an advanced stage of ossification and 4.5% in an intermediate stage, while 4.5% showed treatment failure. CONCLUSIONS: The combination of silver amalgam and irradiation with the Erbium:YAG laser in periapical surgery showed a very high clinical success rate, with a 77.7% bone cavity remodeling rate after 24 months.

Aluminum↗

[The first experience with the concurrent effect of YAG-neodymium and YAG-erbium laser on experimental animal tissues and the possibility of its use in surgery].

To guarantee the necessary rate of cutting live tissues with adequate hemostasis along the line of the incision, the authors studied isolated and joint effect of radiations of AIG-neodymium and AIG-erbium lasers on the tissues of laboratory animals. The possibility of accomplishing intraoperative hemostasis on the parenchymal organs was studied in experiments with AIG-neodymium laser. A good dissection effect in cutting various tissues was produced in the second series of experiments with AIG-erbium laser. The simultaneous action of AIG-neodymium and AIG-erbium beams converged at one point on the surface of the biological object was studied in the third series of experiments. It was found that the effect ensures a good dissection of tissues with sufficient hemostasis. The results of dynamic morphological studies are shown. The possibility of using the device in surgery is discussed.

Animals↗

Erbium filtration in iodine contrast studies.

In iodine contrast studies, an improvement in contrast is theoretically possible by narrowing the energy spectrum around the k-edge of iodine. Heavy metal filtration is a method of narrowing the energy spectrum but other parameters of the examination may be altered. These other parameters must be examined. After establishing the effect of heavy metal (erbium) filtration on the beam energy, the filter is evaluated in a simulated clinical situation. Patient exposure, image contrast, and tube loading are monitored while obtaining radiographs of a phantom comparable to a standard radiograph of the phantom. From this study, it was determined that erbium filtration could be used to decrease patient exposure markedly without significant loss of contrast or an increase in tube loading. Also determined was a set of exposure factors at which the erbium filtration was most effective.

Contrast Media↗

Combination therapy: utilization of CO2 and Erbium:YAG lasers for skin resurfacing.

Skin resurfacing with carbon dioxide (CO2) lasers is a commonly used method for skin rejuvenation. With these lasers, there is substantial skin improvement with lessening of rhytids and skin discoloration, and noticeable skin tightening. However, there is also significant morbidity associated with their use. To decrease the healing and erythema times, other types of lasers have been developed. The author discusses the practice of combining the CO2 and Erbium:YAG lasers for limiting thermal injury. For deeper rhytids in the periorbital, perioral, and forehead regions, multiple passes with the CO2 laser are often the preferred treatment. For moderate rhytids, the CO2 laser can be used for the first pass followed by one to multiple passes with the Erbium:YAG laser. Erbium:YAG lasers when used alone are beneficial for removing fine wrinkles and discolorations. Combining these lasers results in both rhytid improvement and decreased morbidity.

Adult↗

Efficacy of erbium:YAG laser ablation in Darier disease and Hailey-Hailey disease.

BACKGROUND: Among different surgical approaches, dermabrasion and carbon dioxide laser vaporization have been used to treat Hailey-Hailey disease (HHD) (familial benign chronic pemphigus) and Darier disease (DD) (keratosis follicularis), with various results. Because of the erbium: YAG laser's unique absorption characteristics in tissue water, erbium:YAG laser ablation combines the advantages of both techniques, avoiding thermal injury of vaporization and also allowing selectively deeper tissue removal in the follicular lesions of DD. Therefore, good results should be expected in both types of acantholytic disorders. OBSERVATIONS: Four patients (2 with HHD and 2 with DD) with different affected areas were treated with laser ablation. During a follow-up period ranging from 8 to 20 months, complete remission was achieved in 3 patients--2 with DD and 1 with HHD--and significant improvement was achieved in 1 patient with HHD. Histological examination of control biopsy specimens after ablation in 1 patient with DD revealed no signs of the disease and only a slight fibrosis in the papillary dermis. CONCLUSIONS: Erbium:YAG laser ablation effectively removes lesions of both HHD and DD and can also yield excellent long-term results in chronic, recalcitrant cases.

Adult↗

[Holmium:YAG and erbium:YAG infrared laser osteotomy].

The in-vivo bone ablation characteristics of a pulsed solid-state erbium:YAG laser were compared to those of a pulsed solid-state holmium:YAG laser. Partial osteotomies in the maxillary, the mandibulary, and the nasal bones of white rats were performed. The tissue response was examined by light microscopy. Thermal gradients following the laser application were also measured. Over all energy levels tested the erbium:YAG laser produced ablation of bone with minimal thermal damage to the adjacent tissue. The results of this study are promising for future application of the infrared holmium- and erbium:YAG lasers in otorhinolaryngology.

Animals↗

[Erbium:YAG laser surgery on vocal fold tissue].

The application of lasers in microsurgery of the vocal fold has very special requirements. Easy handling as well as a precise cutting quality with a small laser induced thermal necrosis zone are necessary. In this study, an Erbium:YAG laser was evaluated for phonosurgery. For this, vocal folds from the porcine larynx were irradiated with the Erbium laser wavelength of 3 mum. The ablation rate, as well as the mechanical and thermal damage were investigated as a function of pulse duration, repetition rate and laser fluence. The results show that Erbium lasers are well suited for application on the vocal fold. The laser induced thermal damage was restricted to a superficial layer of only about 20-30 microm, resulting in a loss of the multilayered epithelium. Thermal necrosis had a range of about 5 microm. Further investigations on the vocal folds of humans must be performed to determine whether this laser is qualified for clinical applications.

Animals↗

[Endoscopically controlled erbium YAG laser goniotomy. Initial preclinical trials].

INTRODUCTION: Endoscopic erbium-YAG laser treatment is a new approach in glaucoma surgery. In contrast to conventional laser systems, the photoablative erbium-YAG laser allows microperforations of the trabecular meshwork without thermal side effects. We report our first preclinical trials using this new system. METHOD: We used the Endognost system (Schwind Co.). The device combines an endoscope and illumination fiber (0.5 mm diameter), laser fiber (0.5 mm) and a irrigation tube in one probe with a 1.1 mm external diameter. The Endognost system was tested in porcine and enucleated human eyes. All eyes were examined histologically. RESULTS: The endoscopic view into the anterior chamber allows for precise allocation of the laser pulses. Using a single pulse mode with 10 mJ a micropuncture of the trabecular meshwork can be achieved without damaging the adjacent tissue. Using multiple pulses or higher energy levels leads to damage of the posterior wall of Schlemm's canal and to thermal side effects. CONCLUSIONS: Endoscope guided erbium-YAG laser effects on trabecular tissue are comparable to those produced by a 308 nm excimer laser. Therefore, a similar reduction in intraocular pressure can be expected.

Animals↗

[Photo-ablation of the cornea with the erbium:YAG laser].

BACKGROUND: Ablation experiments and preclinical studies have shown increased thermal damage and surface roughness after photorefractive keratectomy (PRK) with the erbium: YAG laser. MATERIALS AND METHODS: In this study, the thermal damage was investigated on enucleated pig corneas for various laser pulse durations (80 ns to 1 ms) and radiant exposures (0.2-5 J/cm2). The "scanning-spot" method and the fundamental mode photo-ablation were used for spherical corrections. SEM pictures and surface roughness measurements enabled comparison with the morphology after ArF-excimer laser treatment. The surface roughness is one order of magnitude higher compared to the ArF-excimer laser ablation. The surface of the tissue after ablation looks melted. RESULTS: The thermal damage reduces with increased intensity, and at high intensities the thermal damage results in a constant thickness of > 5 microns. CONCLUSIONS: Laser-induced melting processes might be the main reason for the high thermal damage and the increased surface roughness after erbium: YAG laser treatment. This leads to the conclusion that the erbium: YAG laser is not a real alternative to the ArF-excimer laser in PRK.

Animals↗

[Erbium:YAG laser vitrectomy: temperature measurements in different replacement materials].

BACKGROUND: The erbium:YAG laser has the potential of being used routinely for vitrectomy because of the excellent quality of liquefying vitreous structures and the low vacuum forces required. However, the use of silicone oil and perfluorocarbon may lead to unwanted temperature increases in the microsurgery probe. The aim of this work was to investigate this side effect. MATERIALS AND METHODS: Different replacement materials such as water, methocel, silicone oil and perfluorocarbon were used in a simple eye model. The temperature increase during laser application was measured by means of thermocouples. The maximum temperature increase and time decay were derived with and without aspiration from these time-resolved measurements. The average power at the distal end of the microsurgery probe was chosen to be 1 W. RESULTS: The temperature increase with aspiration in water was found to be significantly smaller than all other replacement materials. Interruption of aspiration leads to a critical temperature increase of approximately 14 K; however, this increase occurred very slowly (decay time 200 s). A comparable result could be observed for methocel, which was used to simulate condensed vitreous structures. In perfluorocarbon and silicone oil we measured a far higher increase in temperature of up to 130 K within a few seconds. Furthermore, small remnants of carbonized materials can be seen in the microsurgery probe after laser application. CONCLUSIONS: The temperature increase during erbium:YAG laser vitrectomy in water can be considered to be harmless for other intraocular structures. However, insufficient aspiration or increased vitreous condensation leads to increased temperature in the microsurgery probe. Our results demonstrate that the use of erbium:YAG laser vitrectomy in materials such as silicone oil or perfluorocarbons is contraindicated.

Contraindications↗

[Erbium:YAG laser vitrectomy. Initial clinical results].

BACKGROUND: Much interest has been expressed in recent years in the use of erbium:YAG lasers in ophthalmology, particularly for vitrectomy and phacoemulsification. PATIENTS AND METHODS: We performed 54 operations (49 primary, 5 secondary) for pars plana vitrectomy on 53 eyes of 53 patients using the Phacolase erbium:YAG laser at a frequency of 10-100 Hz single-pulse energy of 5-50 mJ. RESULTS: The operation was successful in 51 cases,while in three we had to resort to mechanical vitrectomy due to initial technical problems. CONCLUSION: Erbium:YAG laser vitrectomy was generally fast and caused little mechanical stress to the retina. Complications were only those known from mechanical vitrectomy.The handpiece showed good properties for removing vitreous but not for cutting membranes, although new handpieces specifically for the cutting of membranes are under development.

Adult↗

Erbium-YAG laser-assisted preparation of deep sclerectomy.

BACKGROUND: Deep sclerectomy and viscocanalostomy are becoming more and more popular as non-penetrating filtering procedures. The purpose of the present study was to simplify the technique of this procedure and to reduce the rate of unintended perforations during the preparation of the deep lamella. METHODS: 20 enucleated porcine eyes were used. A superficial lamellar scleral flap with an area of 5x5 mm as for trabeculectomy was surgically prepared. Using a pulsed erbium:YAG laser the deep lamella (220 +/- 40 microm) with an area of 4x3 mm was removed. Ablation was performed with an energy of 40-100 mJ, a frequency of 1-10 Hz and a spot size of 500 microm and 1 mm (divergent beam). During the procedure the intraocular pressure was kept constant by continuous infusion. Finally the eyes were analyzed histologically. RESULTS: After initial trials it was possible to ablate the remaining deep corneoscleral lamella with the erbium:YAG laser without perforating into the anterior chamber. Starting with an energy of 70-85 mJ and a reduction to 40-60 mJ when reaching deeper layers, a spot size of 500 microm and a 10 Hz repetition rate gave the highest safety and efficiency in preparation. After a learning curve it was possible to preserve Descemet's membrane and intact trabecular meshwork in 10 consecutive operations as demonstrated by histology. CONCLUSION: Erbium:YAG laser-assisted deep sclerectomy offers an alternative to microsurgical preparation of the deep scleral lamella. The thermal damage is minimal (10-40 microm) and scarring may therefore not be stimulated.

Animals↗

Free-running erbium:YAG laser for nonmechanical trephination in penetrating keratoplasty: first results of experimental trephination of human donor corneas.

BACKGROUND: A study was carried out to evaluate the potential suitability of a free-running erbium:YAG 2.94-microm laser for trephination of human corneas in penetrating keratoplasty. METHODS: Two human donor corneas were placed in an artificial anterior chamber and moved with an automated rotation device (one rotation per minute). An erbium:YAG laser beam (pulse duration 400 micros, repetition rate 2/s, energy density 2.5 and 15.0 J/cm(2)) was focused on the outer edge of a round ceramic mask placed on the human donor corneas for ablation of tissue. RESULTS: With a fluence of 15.0 J/cm(2), perforation was achieved after 500 pulses. Perpendicular central cut edges with mild stromal ridges and, by light microscopy, a 12 to 45-microm area of stromal thermal effects and focal endothelial changes up to 200 microm central to trephination were observed. CONCLUSIONS: The erbium:YAG laser could be a promising "low-cost alternative" to the excimer laser for nonmechanical trephination in penetrating keratoplasty. Further studies will have to focus on reduction of thermal damage and on wound healing.

Animals↗

Initial clinical experience with an erbium:YAG laser for vitreoretinal surgery.

PURPOSE: We tested the efficacy of an erbium:YAG laser for maneuvers in patients undergoing vitreoretinal surgery. METHODS: An erbium:YAG laser equipped with a flexible fiberoptic and interchangeable 20-gauge endoprobes of various tip configurations ranging from 100 to 365 microns was used for specific maneuvers in 13 patients referred for vitreoretinal surgery for diabetic traction detachment, proliferative vitreoretinopathy, retinal detachment with posterior break, and epimacular membrane. The following maneuvers were performed: (1) transection of elevated vitreous membranes, (2) incision of epiretinal membranes, (3) drainage and relaxing retinotomy, (4) transection of subretinal membranes, (5) noncontact ablation of epiretinal membranes in air-filled eyes, (6) ablation of lens remnants, (7) posterior capsulotomy, (8) iris surgery, and (9) retinal vascular coagulation. RESULTS: Forty-eight defined maneuvers were performed with energy levels ranging from 0.2 to 5.0 mJ and repetition rates of 2 to 30 Hz. Transection of elevated membranes, subretinal membranes, and retinotomies were easily performed. Fourteen incisions into vascularized epiretinal membranes in diabetic traction detachment surgery demonstrated a fine margin of coagulation that permitted hemostatic incision. Retinal breaks were created during one of these incisions. Lens remnant ablation, posterior capsulotomy, and iris tissue removal were successful, with a single complication consisting of damage to the posterior surface of an intraocular lens during a pars plana posterior capsulotomy accomplished by means of a side-firing probe. Epiretinal membrane ablations in air-filled eyes were effectively performed in a gradual fashion without hemorrhage. CONCLUSIONS: The erbium:YAG laser offers precise and effective tissue cutting and removal in vitreoretinal maneuvers. Further study will determine the role of this technology in vitreoretinal surgery.

Adult↗

Comparison of erbium:yttrium-aluminum-garnet-laser vitrectomy and mechanical vitrectomy: a clinical study.

OBJECTIVE: To evaluate the clinical usefulness of the erbium:YAG (yttrium-aluminum-garnet) laser for vitrectomy and to compare it with a conventional mechanical vitrectomy system regarding the intraoperative parameters. DESIGN: Prospective, randomized, clinical trial. PARTICIPANTS: Thirty eyes of 30 patients underwent vitrectomy, 15 eyes in each group. METHODS: For mechanical vitrectomy, a commercially available vitrectomy unit was used. The operating parameters, cutting rate (7 Hz = 420 cpm), maximal suction force (300 mmHg), and aspiration flow (20 ml/min), were held constant. A newly developed erbium (Er):YAG laser unit and handpiece was used for laser vitrectomy with predetermined parameters for cutting rate (70 Hz = 4200 cpm), maximal suction force (50 mmHg), and aspiration flow (20 ml/min). Surgery parameters were recorded in real time and the operation was video recorded. The clinical follow-up time was a minimum of 3 months (average, 6.2 months; range, 3-9 months). MAIN OUTCOME MEASUREMENTS: The surgery time was comparable in both groups. During Er:YAG laser vitrectomy, the average suction force was significantly reduced (P< 0.001) compared with that during mechanical vitrectomy. The mean-square variation in suction as a measure to quantify the forces acting on intraocular structures during surgery was significantly smaller in the Er:YAG laser vitrectomy group (P << 0.001). CONCLUSIONS: Erbium:YAG laser vitrectomy may provide a semicontinuous procedure. This technique minimizes periodical intraoperative forces and movements of intraocular structures and may provide, therefore, a safer vitrectomy.

Aged↗

Erbium:YAG laser surgery of the vitreous and retina.

PURPOSE: These studies evaluated an erbium:YAG laser for transection of vitreous membranes, retinotomy, and incision and ablation of epiretinal membranes. METHODS: Elevated vitreous membranes, detachments, and epiretinal membranes were induced in rabbit eyes. An erbium:YAG laser, emitting at a wavelength of 2.94 microns and equipped with a flexible fiber and endoprobes with tips ranging from 75 to 375 microns, was used to perform vitreous membrane transections, retinotomies, and epiretinal membrane incisions and ablations in nontransmitting aqueous media with the endoprobe in proximity to the tissue. Ablations of epiretinal membranes also were performed in transmitting media, including air and perfluoro-N-octane with the endoprobe elevated above the membrane. RESULTS: Twenty-five vitreous membrane transections were made in 16 eyes at distances ranging from 0.5 to 4.5 mm from the retina with radiant exposures ranging from 2 to 50 J/cm2 with nonhemorrhagic retinal damage in a single transection. Sharp, linear retinotomies were created successfully in five eyes. Epiretinal membrane ablations were performed with radiant exposures ranging from 1.8 to 22.6 J/cm2. In aqueous media, results of microscopic examination showed partial- to full-thickness ablation with a maximum lateral thermal damage of 50 microns. In air- and perfluoro-N-octane-filled eyes, there was increased lateral damage with desiccation of residual tissue. In 12 aqueous-filled eyes, 18 linear incisions were successfully performed, with retinal nonhemorrhagic damage in 2 eyes and hemorrhage in 5. CONCLUSION: The erbium:YAG laser may provide new approaches to maneuvers performed in vitreoretinal surgery.

Animals↗