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The rapid growth in erbium laser resurfacing gives rise to a need for clinicians to become familiar with some new terminology and concepts. The design of erbium laser machines used for these procedures is described giving clinicians a basis for machine selection. The basic concepts of energy, fluence and overlap will allow the clinician to manipulate the laser parameters so as to achieve the desired clinical results.
BACKGROUND: The recent introduction of pulsed erbium-YAG (Er:YAG) laser technology has been accompanied by relatively few clinical studies with widely varying claims regarding post-operative healing, clinical side effects and efficacy. OBJECTIVE: The aim was to evaluate comparatively pulsed CO2 and Er:YAG lasers with regard to clinical side effects, post-operative healing and efficacy when equivalent depths of histologic damage were produced. METHODS: Bilateral periocular or perioral sites were treated using a pulsed CO2 laser on one side and a pulsed Er:YAG laser on the opposite side. Attempts were made to produce equivalent depths of coagulation (CO2) and ablation (erbium). RESULTS: Results showed almost equivalent post-operative healing. However, the pulsed CO2 laser proved more effective in the treatment of moderate and deep rhytids. CONCLUSION: When equivalent depths of coagulation and ablation are compared, the healing time is similar. CO2 proved to be more efficacious in the treatment of perioral and periocular rhytids.
The present study evaluates the morphological changes in root canal walls and temperature changes at root surfaces as a result of intracanal irradiation by erbium,chromium:YSGG laser under various conditions in vitro. Sixty single-rooted human teeth were examined. Root canals were prepared, and laser irradiation was performed using an optic fiber at output powers ranging from 1 to 6 W with or without water spray cooling. Specimens were evaluated by stereoscopy, scanning electron microscopy, and thermography. Carbonization and cracks were observed in all samples irradiated without cooling, whereas little or no carbonization and no smear layer or debris were observed in samples irradiated with cooling. Maximum temperature rise at irradiation without cooling was above 37 degrees C, whereas that at irradiation with cooling was 8 degrees C. Results of the present study indicate that erbium,chromium:YSGG laser irradiation with water spray cooling is a useful method for removal of smear layer and debris from root canals.
The development and integration of pulsed and scanned CO2 and erbium:YAG laser systems into mainstream surgical practice over the past years has revolutionized cutaneous resurfacing. These lasers are capable of delivering to skin high peak fluences to effect controlled tissue vaporization, while leaving an acceptably narrow zone of residual thermal damage. The inherent technological differences that exist between the two distant laser systems in terms of ablation depths, degree of thermal coagulation, and postoperative side-effects and complications guide patient selection and management. This article reviews the basic principles of CO2 and erbium:YAG laser resurfacing, including preoperative, intraoperative, and postoperative patient considerations. Side-effects and complications encountered after laser resurfacing are discussed with specific guidelines provided on their appropriate management. Anticipated future developments and cutting-edge research endeavors in cutaneous laser resurfacing are also briefly outlined.
Titanium screws were implanted in rat calvarial defects of identical size using either a laser or bur. The aims of this study were to determine whether the screws were able to osseointegrate in a laser-prepared bone defect and to compare the pattern of bone healing around these screws. The optimal laser settings to produce a 0.7-mm-diameter hole in the rat calvaria were determined. A 0.7-mm-diameter hole was prepared on the left calvaria with the erbium-YAG laser to receive a 1-mm-diameter self-threading titanium screw. Each animal also received a 0.7-mm-diameter hole prepared on the right calvaria with a conventional metal bur, and a 1-mm-diameter self-threading screw implant was placed. Rats were killed humanely either 3 weeks or 3 months after surgery, and the skulls were processed in paraffin wax for histological analysis. Laser-prepared defects: At 3 weeks, the screw was surrounded by vital woven bone. The dura mater was perforated, and cystic change was present in the underlying brain tissue. There was active bone formation adjacent to the screw surface, deposited on a thin zone of necrotic bone. At 3 months, the screws were osseointegrated, and the brain tissue was healed by gliosis. Bur-prepared defects: At 3 weeks, there was extensive remodeling around the prepared defect. The dura mater was intact, and there was no damage to the underlying brain. At 3 months, the screws were successfully osseointegrated with bone adjacent to the screw. Osseointegration of titanium screws can be achieved using an erbium-YAG laser to prepare the implant bed.
The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.
PURPOSE: To study the anatomic structure and the endoscopic aspect of the lacrimal drainage system and to evaluate the efficacy of the Erbium laser with microendoscope in lacrimal obstruction. METHODS: Twenty lacrimal ducts from ten fresh cadaver heads were used to lead a special rigid probe of 1.1. mm diameter (Endognost Schwind). This probe combined a flexible endoscopic probe of 500 mu, an Erbium laser fiber of 375 mu and an irrigation. The probe was introduced through the inferior canaliculus. Progressing in the lacrimal system, all the images were analysed. Then, we used the laser fiber to open the lacrimal sac mucosa and the lacrimal bone. RESULTS: The anatomo-endoscopic analysis was performed using endoscopic data. We appreciated essentially the walls of valves and sinuses that appeared only functional when increasing the irrigation flow. The laser could easily open the mucosa and the lacrimal bone but not the maxilla. DISCUSSION: The small size of the cannula allows to use the system for the diagnosis of lacrimal obstructions. The combined laser allows to treat at same time canalicular obstructions and lower obstructions. CONCLUSION: The endocanalicular study of the lacrimal drainage system can diagnose the type of obstruction and can treat it. A clinical study is requested to confirm these results.
Melanin, carotene and hemoglobin are the most common natural pigments contributing to the normal color of the gums. Although physiologic and ethnic melanin pigmentation is not a medical problem, complains about "black gums" are common. Gingival depigmentation has been carried out using surgical, chemical, electrosurgical and cryosurgical procedures. Recently, Laser Ablation has been recognized as one of the most effective, pleasant and reliable techniques. Effective depigmentation of the gingival requires removal of all or most of the melanocytes from the basal layer of the gingival epithelium. Using non-specific radiation means ablation of all the epithelial cell layers, as well as connective tissue rete pegs, leaving behind only remnants of the epithelial rete ridges. CO2, Nd:YAG and Erbium:YAG lasers, meeting most of these requirements and being available in the dental office, seems to be the lasers of choice for this procedure. Five patients (3 F; 2 M) who were referred to the TAUSDM for cosmetic therapy of "black gums" were treated using Erbium-YAG laser. The laser beam was set up at 850 mj/10 pulses per second producing peak power of 2.13 kwand peak power density of 30.43 kw/sq/cm. The beam was defocused to produce a 3 mm diameter circle, thus reducing the beam penetration while increasing the treated surface. Using the "brush" technique, 800-2,000 pulses were required per patient, with an average of 500-1,100 pulses per 1 sq.cm, depending on the thickness of the epithelium and the intensity of the pigmentation. Treatment required only topical anesthesia. Healing was uneventful and required no supportive therapy. Three months follow up has shown no repigmentation in any of the patients. Patients' evaluation analysis showed that the results were pleasing; no pain was experienced during lasing as well as during healing. Two patients were interupted by the lasing burning smell, which may be reduced or eliminated by operating a power suction during the procedure.
The authors report their experience in the treatment of metatarsophalangeal arthritis of chronic inflammatory rheumatism by Erbium 169 synoviortheses (112 joints treated) and by infiltrations of triamcinolone hexacetonide (53 joints treated). The steroid appears to have a marked early superiority as it gives 85% good results compared to 61.6% for Erbium 169 after a period of one to three months. However, its results then deteriorate more rapidly and after 6 months, the proportion of good results is greater with the radioactive treatment (64% compared to 46.7%). The authors consider it reasonable to use triamcinolone hexacetonide as the first line treatment as it is easier to manage and less expensive, reserving the radioactive synoviortheses for later with the prospect of more lasting results.
OBJECTIVE: To induce complete and reproducible repigmentation of large "stable" vitiligo lesions by means of autologous cultured epidermal grafts using a rapid, simple, and minimally invasive surgical procedure. DESIGN: Achromic epidermis was removed by means of appropriately settled erbium:YAG laser, and autologous epidermal grafts were applied onto the recipient bed. Melanocyte content was evaluated by dopa reaction. The percentage of repigmentation was calculated using a semiautomatic image analysis system. SETTING: A biosafety level 3-type cell culture facility, a surgical ambulatory department, and a dermatological department in a hospital. PATIENTS: Twenty-one patients with different types of vitiligo were admitted to the study and treated with autologous cultured epidermal grafts. Inclusion criteria were failure of at least 2 standard medical approaches; no therapy for at least 12 months; no progression of old lesions or appearance of new lesions; no Koebner phenomenon within the past 18 months; and no autoimmune disorders. RESULTS: The average percentage of repigmentation in 21 patients was 75.9% (1759.7 cm2 repigmented/2315.8 cm2 transplanted). Three patients showed a reactivation of their vitiligo and did not show repigmentation. The remaining 18 patients, with 43 distinct lesions, showed an average percentage of repigmentation of 90% (1759.7 cm2 repigmented/1953.4 cm2 transplanted). CONCLUSIONS: Under appropriate conditions, cultured epidermal grafts induce complete repigmentation of stable vitiligo lesions. Erbium:YAG laser surgery can supply a fast and precise tool for disepithelialization, hence allowing treatment of large vitiligo lesions during a single surgical operation.
We used a pulsed erbium-YAG laser emitting in the midinfrared region (2.94 microns) to cut experimental vitreous membranes in rabbits via an intraocular fiberoptic delivery system. Thirty-four membranes were cut at distances of 500 to 3600 microns from the retina. All 34 of the membranes treated were effectively cut. Sixteen cases had no evidence of retinal injury, including one in which the membrane was only 800 microns from the retina. Retinal injuries in the remaining cases consisted of small (less than 300 microns) retinal burns and hemorrhages. In 94% of the cases with retinal injury, the fiberoptic was within 2000 microns of the retina. We conclude that a pulsed erbium-YAG laser allows near tractionless cutting of vitreous membranes and may have potential for clinical use if further studies show it to be efficacious and safe near the retina.
BACKGROUND AND OBJECTIVE: The aim of this study was to examine the pattern of healing in rat calvarial defects prepared with the erbium-YAG laser, using the "guided tissue regeneration" technique [Dahlin et al., Scand J Plast Reconstr Hand Surg 1990;24: 13-19]. STUDY DESIGN/MATERIALS AND METHODS: PTFE membranes were placed over the lased skull defects and the skin wounds sutured. Rats were killed humanely at intervals after surgery and the skulls processed for paraffin wax histology. A further group of mature rats was killed humanely and the calvariae removed. Slots were prepared using the erbium-YAG laser and immediately examined under the environmental scanning electron microscope (ESEM) in hydrated conditions, which avoided drying artefact. RESULTS: An amorphous, mineral-rich carbon layer surrounds the lased bone defect, which in the in vivo experiments was seen as a basophilic zone that was resistant to resorption. CONCLUSION: Bone infilling of the lased defect was retarded by delayed resorption of the amorphous, mineral-rich carbon layer.
BACKGROUND AND OBJECTIVE: Laser trabecular ablation (LTA) aims to remove trabecular tissue and to open Schlemm's canal in order to improve outflow facility in glaucomatous eyes. The purpose of our study was to investigate the pressure-reducing effect of LTA in chronic open-angle glaucoma 1 year following laser surgery. STUDY DESIGN/MATERIALS AND METHODS: Eleven eyes of 11 patients with chronic open-angle glaucoma were treated by circumscribed laser ablation of the trabecular meshwork. We used an Erbium:YAG laser (2.94 microm) with a quartz fiber contact endoprobe (320 microm core-diameter, 385 microm coating-diameter) applying 11-30 single neighbouring laser pulses (5-7 mJ) to the trabecular meshwork by an ab-interno approach. Laser procedure was gonioscopically visualized. RESULTS: Mean maximum intraocular pressure (IOP) of all 11 patients before LTA was 36 mmHg and dropped down to 22 mmHg after a mean follow-up of 12 months following LTA; this represents an IOP decrease of 38% (P=0.008). The average number of medications per eye dropped from 2.8 to 1.5 per eye (P=0.021). CONCLUSION: Although IOP lowering effect of Erbium:YAG laser trabecular ablation did not prove as effective as in filtering procedures, LTA might be a valuable alternative in glaucoma surgery especially in order to avoid conjunctival scarring and postoperative hypotony.
BACKGROUND AND OBJECTIVE: To compare the in vivo histologic effects of the pulsed carbon dioxide (CO(2)) and erbium:ytrium aluminum garnet (Er:YAG) lasers and to assess the effects of combining CO(2) and Er:YAG laser modalities during a single treatment session. We previously reported 10 patients treated with four laser regimens: CO(2) alone, CO(2)/Er:YAG, Er:YAG alone, Er:YAG/CO(2) with time points at 1 hour and 7 days between laser treatment and histologic analysis. This study found that the optimal treatment consisted of limited CO(2) laser passes followed by Er:YAG. This treatment produced less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration in the acute phase of healing. The present study examines the histologic changes resulting from the host healing response to laser treatment on long-term follow-up of 4-6 months. STUDY DESIGN/MATERIALS AND METHODS: The Stanford University Committee on Human Subjects in Medical Research approved this study. Nine patients with actinic damage and indications for rhytidectomy volunteered for this interventional study in which each patient served as both experimental and control. The right preauricular area was treated at five sites with the following: (1) CO(2), (2) CO(2) followed by Er:YAG, (3) Er:YAG, (4) blended CO(2)/Er:YAG (Derma-Ktrade mark), (5) phenol. Each was subjected to full-face or sub-unit treatment. Each patient was followed up initially daily then weekly for healing of the full-face laser and for differences in healing of the five treatment areas. Five patients were selected for histologic evaluation. At 4-6 months, these patients underwent rhytidectomy with immediate removal of laser-treated skin, which was evaluated histologically by the study dermatopathologist, who was blinded to the treatment at each site. RESULTS: CO(2) laser treatment produced the greatest thickness of neocollagen (0.27 mm; P < 0.05), the highest neocollagen density (P < 0.05), the greatest decrease in elastosis (27%), but took the longest time for healing and resolution of erythema and inflammation (up to 6 months). Er:YAG used alone produced the least collagen density, with the thinnest band of neocollagen (0.08 mm), but the most rapid resolution of erythema and inflammation (within 10 days). Combined CO(2)/Er:YAG treatments, including Derma-Ktrade mark and CO(2) followed by Er:YAG produced histologic changes that were intermediate, as well as recovery that was intermediate (resolution of erythema within 1 month); the development of neocollagen was greater in CO(2)-containing modalities than Er:YAG used alone by a statistically significant margin (P = 0.001). These histologic findings were corroborated by clinical correlation by examination of the five treatment spots in nine patients and in full-face treatments in 100 patients. CONCLUSION: Collagenesis is greatest with CO(2) and least with Er:YAG. Elastosis decreased to the greatest degree with CO(2), least with erbium, and to an intermediate extent with blended CO(2)/Er:YAG regimens (sequential and Derma-K). These changes from control are statistically significant with all regimens (P < 0.05). Blended CO(2)/Er:YAG treatments provide an optimal combination of the benefits of CO(2) but with lesser erythema and healing delay. Clinical and histologic findings change over time for different treatments. Thus, long-term histology is critical for predicting results of treatment.
Photoablative laser trabecular surgery has been proposed as an outflow-enhancing treatment for open-angle glaucoma. The aim of the study was to investigate the time course of repair response following low-thermal Erbium: YAG laser trabecular ablation. In 20 anaesthetized rabbits gonioscopically controlled ab-interno photoablation of the ligamenta pectinata and underlying trabecular meshwork (TM) was performed with a single-pulsed (200 microseconds) Erbium: YAG (2.94 microns) laser. The right eye received 12-15 single laser pulses (2 mJ) delivered through an articulated zirconium fluoride fiberoptic and a 200 microns (core diameter) quartz fiber tip, the left unoperated eye served as control. At time intervals of 30 minutes, 2, 10, 30, and 60 days after laser treatment, eyes were processed for light- and scanning electron microscopy. The applied energy density of 6-4 J cm-2 resulted in visible dissection of the ligamenta pectinata and reproducible microperforations of the TM exposing scleral tissue accompanied by blood reflux from the aqueous plexus. The initial ablation zones measured 154 +/- 36 microns in depth and 45 +/- 6 microns in width. Collateral thermal damage zones were 22 +/- 8 microns. At two days post-operative, ablation craters were still blood- and fibrin-filled. The inner surface of the craters were covered with granulocytes. No cellular infiltration of the collateral thermal damage zone was observed. At 10 days post-operative, progressive fibroblastic proliferation was observed, resulting in dense scar tissue formation with anterior synechiae, proliferating capillaries and loss of intertrabecular spaces inside the range of former laser treatment at 60 days post-operative. Trabecular microperforations were closed 60 days after laser treatment in all rabbits. IOP in treated and contralateral eyes did not significantly change its level during whole period of observation. Low-thermal infrared laser energy with minimal thermal damage to collateral structures could not effectively prevent early scarring of trabecular surgery in rabbits.
The reasons for the development of pulsed lasers, as well as the differences between them and continuous lasers are discussed. Both the advantages and disadvantages of such lasers, as well as the indications are presented. Furthermore, the erbium-yag laser is contrasted to the ultra-pulsed CO2 laser. Two case reports demonstrate the effectiveness of the erbium-yag laser.
BACKGROUND: Erbium laser sclerostomy (ELS) ab externo is a minimally invasive addition to conventional fistulating glaucoma surgery. To date, the success rate of this method is lower than that of trabeculectomy or goniotrepanation. The chief cause of therapy failure is postoperative episcleral scarring of the bleb. It was the aim of the present study to decrease the occlusion rate of this complication. PATIENTS AND METHODS: 41 eyes were treated with subconjunctival injections of 5-fluorouracil perioperatively to an intended total dose of 40 mg to prevent episcleral scarring. At the same time, bigger probe diameters were used (550 microns and 700 microns instead of 300 microns). RESULTS: After 3 months, the proportion of patients with regulated intraocular pressure after using bigger probe diameters combined with anti-proliferative therapy was significantly higher (550 microns fiber +5-FU: 73%; 700 microns fiber +5-FU: 71%) than for a 300 microns fiber without 5-FU (38%). Average intraocular pressure in successful cases was 11.6 +/- 4.2 mmHg in the 550 microns fiber +5-FU group and 12.3 +/- 4.0 mmHg in the 700 microns fiber +5-FU group. CONCLUSION: The short-term results of erbium laser sclerostomy as a minimally invasive technique can be improved by using increasing laser fiber diameters and by perioperative injections of 5-FU to prevent episcleral fibrosis.
Perioral hyperpigmentation is commonplace in practice; it can be a physiological finding or reflect a systemic life-threatening disease or syndromes, this is treated with different types of application. A 20-year-old female with isolated perioral hyperpigmentation and treatment of this lesion with an erbium:YAG laser is shown. There were no other signs and symptoms in this patient. Another pathological finding could not be determined during examinations, laboratory tests and radiological studies. The erbium:YAG laser was applied to the hyperpigmented area. There was no complication after laser application and an aesthetically successful result with patient satisfaction was achieved in both early and late terms. According to our knowledge this is the first report, which has described the isolated idiopathic type of perioral hyperpigmentation.