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At least 73 records · Page 4Linked to original sources

PubMed1999

Laser irradiation of bone: II. Healing response following treatment by CO2 and Nd:YAG lasers.

BACKGROUND: Currently, the most commonly used lasers for dental procedures are the Nd:YAG and CO2. Studies comparing healing of osteotomy defects prepared with rotary burs to those created by laser irradiation have reported conflicting results. The purpose of this study was to evaluate and compare the histologic healing of bone in rat tibial osteotomy defects created either by a dental bur, CO2 laser with and without removal of the char layer, and Nd:YAG laser with char layer removed and with and without use of an air/water surface cooling spray. METHODS: Tibial osteotomy defects were created in 4 groups of 6 rats each using the following: 1) #6 round bur with simultaneous saline irrigation; 2) CO2 laser with char layer intact; 3) CO2 laser with char layer removed; 4) Nd:YAG laser with air/water surface cooling, and char layer intact; 5) Nd:YAG laser with air/water surface cooling, and char layer removed; and 6) Nd:YAG laser without air/water surface cooling, and char layer removed. Both laser types were used at energy densities typically utilized for oral soft tissue surgery. RESULTS: Progressive healing from day 0 through day 21 post-treatment was observed in all treatment groups. However, compared to controls treated by rotary dental bur, those specimens treated by laser, regardless of laser type, energy density, or other parameters, exhibited a delay in healing that appeared to be related to the presence of residual char in the osseous defect. Specimens treated with the Nd:YAG laser using an air/water surface coolant exhibited a decreased thickness and continuity of the char layer and yielded the only specimens with new bone formation at the surface of the laser ablation defect. In addition, the normal pattern of bone remodeling in the rat tibia appeared to have been altered by laser irradiation. CONCLUSIONS: In this animal model, laser-induced osteotomy defects, when compared to those prepared by rotary bur, exhibited a delayed healing response that appeared to be related to the presence of residual char in the osseous defect.

Animals↗

PubMed1997

Laser skin resurfacing with the Q-switched Nd:YAG laser.

BACKGROUND: Recent studies have shown that char-free pulsed carbon dioxide lasers are useful in the treatment of rhytids. Other infrared lasers have also been observed to induce changes in the skin. OBJECTIVE: In this pilot study, we evaluated the rhytid resurfacing capability of the Q-switched neodymium:yttrium-aluminum-garden (QS Nd:YAG) laser at 1064 nm as compared with char-free carbon dioxide lasers at 10,600 nm. METHODS: Three lasers were used in the study: The QS Nd:YAG laser, the SilkTouch carbon dioxide laser, and the UltraPulse carbon dioxide laser. Eleven subjects were treated in either the periorbital or perioral region with the QS Nd:YAG laser on one side of the face, and both of the char-free pulsed carbon dioxide lasers on the other side. The subjects were evaluated at posttreatment days 7, 30, 60, and 90 for improvement of rhytids, healing, pigmentary changes, and erythema. RESULTS: All 11 patients treated with the char-free carbon dioxide lasers improved. Nine of 11 patients treated with the QS Nd:YAG laser were improved. Healing (complete reepithelialization) was noted to occur 3-6 days earlier in sites treated with the QS Nd:YAG than in sites treated with char-free carbon dioxide lasers. Pigmentary changes were not observed in any treatment site. Erythema was observed at 1 month after treatment in all areas treated with the char-free carbon dioxide lasers, but only three patients treated with the QS Nd:YAG exhibited erythema. These were the same three QS Nd:YAG-treated patients whose clinical improvement was comparable with that of the char-free carbon dioxide lasers. CONCLUSION: The Q-switched Nd:YAG laser may play a role in the treatment of rhytids.

Dermatologic Surgical Procedures↗

PubMed2004

Comparative evaluation of diode laser versus argon laser photocoagulation in patients with central serous retinopathy: a pilot, randomized controlled trial [ISRCTN84128484].

BACKGROUND: To evaluate the efficacy of diode laser photocoagulation in patients with central serous retinopathy (CSR) and to compare it with the effects of argon green laser. METHODS: Thirty patients with type 1 unilateral CSR were enrolled and evaluated on parameters like best corrected visual acuity (BCVA), direct and indirect ophthalmoscopy, amsler grid for recording scotoma and metamorphopsia, contrast sensitivity using Cambridge low contrast gratings and fluorescein angiography to determine the site of leakage. Patients were randomly assigned into 2 groups according to the statistical random table using sequence generation. In Group 1 (n = 15), diode laser (810 nm) photocoagulation was performed at the site of leakage while in Group 2 (n = 15), eyes were treated with argon green laser (514 nm) using the same laser parameters. Patients were followed up at 4, 8 and 12 weeks after laser. RESULTS: The mean BCVA in group 1 improved from a pre-laser decimal value of 0.29 +/- 0.14 to 0.84 +/- 0.23 at 4 weeks and 1.06 +/- 0.09 at 12 weeks following laser. In group 2, the same improved from 0.32 +/- 0.16 to 0.67 +/- 0.18 at 4 weeks and 0.98 +/- 0.14 at 12 weeks following laser. The improvement in BCVA was significantly better in group 1 (p < 0.0001) at 4 weeks. At 4 weeks following laser, all the patients in group1 were free of scotoma while 6 patients in group 2 had residual scotoma (p < 0.05). The mean contrast sensitivity in group 1 improved from pre-laser value of 98.4 +/- 24.77 to 231.33 +/- 48.97 at 4 weeks and 306.00 +/- 46.57 at 12 weeks following laser. In group 2, the same improved from 130.66 +/- 31.95 to 190.66 +/- 23.44 at 4 weeks and 215.33 +/- 23.25 at 12 weeks. On comparative evaluation, a significantly better (p < 0.001) improvement was noted in group 1. CONCLUSION: Diode laser may be a better alternative to argon green laser whenever laser treatment becomes indicated in patients with central serous retinopathy in terms of faster visual rehabilitation and better contrast sensitivity. In addition, diode laser also has the well-recognized ergonomic and economic advantages.

Adult↗

PubMed2005

Comparison of a 1,064 nm laser and a 1,320 nm laser for the nonablative treatment of acne scars.

BACKGROUND: There have been many reports of the use of nonablative lasers for the treatment of acne scars. OBJECTIVE: To evaluate the ability of the 1,064 nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to treat acne scars and compare it with that of the 1,320 nm Nd:YAG laser. METHODS: Twelve patients with Fitzpatrick skin types I to III were randomly selected to have half of the face or back treated with the Lyra 1,064 nm Nd:YAG laser (Laserscope Corporation, San Jose, CA, USA) and the other half with the CoolTouch II 1,320 nm Nd:YAG laser (ICN Pharmaceuticals, Inc., Costa Mesa, CA, USA). Three treatments at 4-week intervals were performed. Patients were evaluated by photographic and profilometric methods before and 6 months after the last treatment. RESULTS: Immediate changes included mild erythema with the 1,064 nm Nd:YAG laser and mild edema and erythema with the 1,320 nm Nd:YAG laser. No long-term adverse changes were seen with either laser system. Using the 1,320 nm system, 42% of the patients had 30 to 40% clinical improvement, 42% had 11 to 29%, and 16% had 10% or less. With the 1,064 nm system, 58% had 30 to 40% clinical improvement and 42% had 11 to 29%. Average improvement in acne scars evaluated by three independent observers was 22% with the 1,320 nm laser compared with 28% with the 1,064 nm laser. The subjects' own grading was 39% with the 1,320 nm laser compared with 37% for the 1,064 nm laser. Prolifometric studies demonstrated comparable improvement, with no statistical difference using either laser. CONCLUSION: These data indicate that both the 1,064 nm laser and the 1,320 nm Nd:YAG laser are safe and effective systems for the nonablative treatment of acne scars, achieving similar improvement. There appears to be a greater response with the 1,064 nm laser system as assessed by the clinical investigators.

Acne Vulgaris↗

PubMed1998

Color vision deficits during laser lithotripsy using safety goggles for coumarin green or alexandrite but not with holmium:YAG laser safety goggles.

PURPOSE: Laser lithotripsy requires urologists to wear laser eye protection. Laser eye protection devices screen out specific light wavelengths and may distort color perception. This study tests whether urologists risk color confusion when wearing laser eye protection devices for laser lithotripsy. MATERIALS AND METHODS: Urologists were tested with the Farnsworth Dichotomous Test for Color Blindness (D-15) and the Farnsworth-Munsell 100-Hue Test (FM-100) without (control) and with laser eye protection devices for coumarin green, alexandrite and holmium:YAG lasers. Error scores were tabulated. The pattern of color deficits was characterized with confusion angles, confusion index (C-index), scatter index (S-index) and color axes. Laser eye protection devices were tested with spectrophotometry for spectral transmittance and optical density. RESULTS: The D-15 transposition errors (mean plus or minus standard deviation) for control, holmium:YAG, alexandrite and coumarin green laser eye protection were 0 +/- 0, 0 +/- 0, 0.3 +/- 0.5 and 6.4 +/- 1.6, respectively (p = 0.0000001). The FM-100 error scores (mean plus or minus standard deviation) were 20 +/- 15, 20 +/- 14, 91 +/- 32 and 319 +/- 69, respectively (p = 0.0001). The confusion index scores indicated a mild color confusion for the alexandrite and pronounced color confusion for the coumarin green laser eye protection. The confusion angles and scatter indexes mimicked a congenital blue-yellow deficit for coumarin green laser eye protection. Color axes showed no significant deficits for control or holmium:YAG laser eye protection in any subject, red-green axis deficits in 3 of 6 tested with alexandrite and blue-yellow axis deficits in 12 of 12 tested with coumarin green (p < 0.001). Spectrophotometry showed that laser eye protection for coumarin green blocks light less than 550 nm., alexandrite blocks light greater than 650 nm. and holmium:YAG blocks light greater than 825 nm. CONCLUSIONS: Laser eye protection for coumarin green causes pronounced blue-yellow color confusion, whereas alexandrite causes mild red-green color confusion among urologists, holmium:YAG causes no significant color confusion compared to controls. The differences are explained by laser eye protection spectrophotometry characteristics and visual physiology.

Adult↗

PubMed1997

Holmium:YAG laser and pulsed dye laser: a cost comparison.

BACKGROUND AND OBJECTIVE: This study was designed to evaluate the relative cost effectiveness of the Holmium:YAG laser and the pulsed dye laser for the treatment of ureteral calculi. Cost containment is a priority for every health care facility. As a result, the staff of the Lutheran Medical Center (Wheat Ridge, CO) looked at alternative ways to provide quality laser treatment of ureteral stones. As part of our study, the laser committee offered the Holmium:YAG laser to urologists for ureteral lithotripsy. Previously, the pulsed dye laser was rented for ureteral calculi on a per case basis at $1,500. A hospital processing fee was added to this cost, resulting in a total charge of $1,638 to the patient. Our organization owns a Holmium:YAG laser and uses it primarily in orthopedics. STUDY DESIGN/MATERIALS AND METHODS: Two ureteral lithotripsy cases were performed and compared. One case used the Holmium:YAG for ureteral lithotripsy; the other procedure used the pulsed dye laser. A cost analysis was performed after the procedures. RESULTS: The data indicated a significant difference in cost between the two lasers. Approximately $1,000 was eliminated when using the Holmium:YAG laser. CONCLUSION: A cost savings of $15,000 per year would be realized if 15 cases were performed. The Holmium:YAG laser also can be used on cystine calculi, a procedure for which the pulsed dye laser is ineffective. The potential for ureteral injury exists. When using the Holmium:YAG laser, appropriate training is required. Due to this risk, not all urologists will use the Holmium:YAG laser. We also found a positive correlation between the proficiency of the urologists' laser skills and overall cost effectiveness.

Cost Savings↗

PubMedDate not supplied

Quantitation of colonic injury from argon laser, neodymium: YAG laser and monopolar electrocautery applied to flat mucosa and small sessile polyps of the canine colon.

This study determined the optimum laser energy for ablation of colonic mucosal lesions and small sessile polyps in the canine colon. Neodymium (Nd):YAG laser, argon laser, and monopolar electrocautery were applied to exposed canine colonic mucosa for various application times at various power settings. At the minimum energy level necessary to ablate mucosa, the Nd:YAG laser caused greater muscularis injury than the argon laser and monopolar electrocautery. At higher energy levels, monopolar electrocautery and Nd:YAG laser caused greater muscularis injury than argon laser. Small surgically created polyps in the canine colon were ablated endoscopically with the three energy sources. Single-session complete polyp ablation occurred most frequently with Nd:YAG laser and least frequently with argon laser. The depth of tissue injury beneath polyp ablation sites was least with argon laser and greatest with Nd:YAG laser. This study suggests that the argon laser is safer than the Nd:YAG laser or monopolar electrocautery for coagulation of flat colonic mucosal lesions. Although the argon laser is safer for the coagulation of small sessile colonic polyps, it may be less effective than monopolar electrocautery or the Nd:YAG laser for the single-session fulguration of polyps greater than 5 mm in diameter.

Animals↗

PubMed1999

Color vision deficits and laser eyewear protection for soft tissue laser applications.

PURPOSE: Laser safety considerations require urologists to wear laser eye protection. Laser eye protection devices block transmittance of specific light wavelengths and may distort color perception. We tested whether urologists risk color confusion when wearing laser eye protection devices for laser soft tissue applications. MATERIALS AND METHODS: Subjects were tested with the Farnsworth-Munsell 100-Hue Test without (controls) and with laser eye protection devices for carbon dioxide, potassium titanyl phosphate (KTP), neodymium (Nd):YAG and holmium:YAG lasers. Color deficits were characterized by error scores, polar graphs, confusion angles, confusion index, scatter index and color axes. Laser eye protection device spectral transmittance was tested with spectrophotometry. RESULTS: Mean total error scores plus or minus standard deviation were 13+/-5 for controls, and 44+/-31 for carbon dioxide, 273+/-26 for KTP, 22+/-6 for Nd:YAG and 14+/-8 for holmium:YAG devices (p <0.001). The KTP laser eye protection polar graphs, and confusion and scatter indexes revealed moderate blue-yellow and red-green color confusion. Color axes indicated no significant deficits for controls, or carbon dioxide, Nd:YAG or holmium:YAG laser eye protection in any subject compared to blue-yellow color vision deficits in 8 of 8 tested with KTP laser eye protection (p <0.001). Spectrophotometry demonstrated that light was blocked with laser eye protection devices for carbon dioxide less than 380, holmium:YAG greater than 850, Nd:YAG less than 350 and greater than 950, and KTP less than 550 and greater than 750 nm. CONCLUSIONS: The laser eye protection device for KTP causes significant blue-yellow and red-green color confusion. Laser eye protection devices for carbon dioxide, holmium:YAG and Nd:YAG cause no significant color confusion compared to controls. The differences are explained by laser eye protection spectrophotometry characteristics and visual physiology.

Adult↗

PubMed1996

Reactions of meniscal tissue after arthroscopic laser application: an in vivo study using five different laser systems.

In many clinical and in vitro studies, the effect of laser radiation on meniscal tissue was examined. Clinical studies referred to clinical criteria like swelling, effusion, and pain to evaluate laser effects. In vitro studies showed the laser effect in the moment of cutting the tissue. But the effect of laser radiation on biological tissue also depends on the vital reaction of the tissue. So, the real extent of tissue damage caused by laser irradiation can only be examined in long-term in vivo studies. This was the purpose of this study. Seventy-two knees of pigs underwent arthroscopic meniscal cuts in the anterior horn of the medial meniscus. The pigs were divided into 6 groups: The first 5 groups were operated with 5 different laser systems: Neodym: YAG 1,440-nm wavelength; Nd:YAG 1,064-nm wavelength, Excimer, Holmium:YAG, and CO2. The sixth group was operated with mechanical punches. From each group, the menisci of the pigs were examined macroscopically and by light-microscope after survival periods of 0, 2, 6, 12 weeks. Results were as follows. (1) All laser systems caused greater damage to the meniscal tissue than mechanical instruments. (2) This damage was a biological reaction of the tissue, characterized by a necrotic zone surrounding the meniscus cut. (3) This necrotic zone was not visible intraoperatively but only 2, 6 and 12 weeks after operation. The diameter of the necrotic zone ranged between 1.5 nm and 9 mm. (4) Meniscus cuts with mechanical instruments showed no necrotic zone in the surrounding tissue. (5) Laser cuts in the meniscus caused more extensive healing reaction than cuts with mechanical instruments. (6) The quality of this healing reaction varied with the different laser systems: the Nd:YAG 1,064-nm, Ho:YAG, and CO2 laser caused only an incomplete healing because the tissue repair showed by tissue growing from the synovial edge into the defect only. The Nd:YAG 1,440-nm wavelength and Excimer led to tissue growing from the synovial edge and to remodeling of original meniscal tissue, recognizable by reduction of the necrotic zone. Arthroscopic surgeons should be aware that the damage to meniscus tissue caused by a laser is much greater than can be seen intraoperatively and is much greater than the damage caused by mechanical punches. The healing reaction of the tissue is more extensive after laser application than after use of mechanical instruments. Results of in vitro studies on the tissue damage caused by lasers are insufficient to describe the whole extent of laser effects on living tissue.

Animals↗

PubMed2006

Treatment of inflammatory facial acne with the 1,450 nm diode laser alone versus microdermabrasion plus the 1,450 nm laser: a randomized, split-face trial.

BACKGROUND: The 1,450 nm laser has been effective in treating acne. Microdermabrasion may help treat acne and reduce skin barriers to increase the delivery rate of topical anesthetics. OBJECTIVES: To evaluate the efficacy, safety, and pain associated with the treatment of inflammatory facial acne with the 1,450 nm laser alone versus microdermabrasion plus the 1,450 nm laser. METHODS: Twenty patients with facial acne were treated with the 1,450 nm laser alone and microdermabrasion plus the 1,450 nm laser in a randomized, split-face trial. RESULTS: Laser alone and microdermabrasion plus laser significantly reduced the total number of acne lesions. Mean reductions of 53.5% and 55.6% were found after three treatments for laser alone and microdermabrasion plus laser, respectively. Clinical improvement was maintained 12 weeks after the last treatment. Mean pain scores were 5.3 6 1.5 for microdermabrasion plus laser and 5.2 6 1.5 for laser alone. There was no statistical difference between treatment levels for efficacy or pain. There was an average 10% increase in sequential pain as the laser treatment progressed. CONCLUSION: The 1,450 nm laser is effective, well tolerated, and safe for treating facial acne. This small pilot study did not demonstrate increased clinical efficacy or decreased associated pain with the addition of microdermabrasion to treatment with the 1,450 nm laser. A larger study may be needed to demonstrate any additional benefit.

Acne Vulgaris↗

PubMed1998

A comparison of argon laser and diode laser photocoagulation of the trabecular meshwork to produce the glaucoma monkey model.

PURPOSE: To create an experimental glaucoma monkey model using high-power diode laser photocoagulation of the trabecular meshwork, and to compare this with the experimental glaucoma monkey model induced by argon laser photocoagulation of the trabecular meshwork. METHODS: One eye each of eight adult cynomolgus monkeys underwent repeated application of diode laser photocoagulation of the trabecular meshwork until sustained intraocular pressure (IOP) elevation was achieved. 50 to 120 spots were applied to midtrabecular meshwork for 360 degrees; spot size, 75 microns; power, 1.2 W; duration, 0.5 seconds. Intraocular pressure, tonographic outflow facility, and ophthalmoscopically and photographically documented optic nerve head evaluations were carried out before and after treatment. Data were compared retrospectively with similar data from an experimental glaucoma monkey model after argon laser photocoagulation of the trabecular meshwork (n = 10). RESULTS: The average number of laser treatments to achieve stable IOP elevation was 3.0 with both diode and argon laser trabecular treatments (p > 0.99). On week 4 after initial pressure elevation, peak IOP was greater--(p < 0.05) 43.0 mmHg +/- 2.4 mmHg (mean +/- SEM) and 37.4 mmHg +/- 1.3 mmHg--in the diode laser-induced than in the argon laser-induced glaucomatous eyes, respectively. Outflow facility (microliter/min/mmHg) was reduced (p < 0.001) in both diode (0.09 +/- 0.01 microliter/min/mmHg) and argon (0.10 +/- 0.01 microliter/min/mmHg) laser-induced glaucomatous eyes compared with untreated fellow eyes. Both the diode and argon laser techniques produced the earliest signs of optic nerve head excavation within about one month of IOP elevation. CONCLUSIONS: Repeat diode laser photocoagulation of the trabecular meshwork produced higher (p < 0.05) IOP elevation than argon laser photocoagulation of the trabecular meshwork in this study. No significant differences in outflow facility and optic nerve head change were observed between these two laser techniques. The experimental glaucoma monkey model can be created with either the diode or argon laser photocoagulation of the trabecular meshwork.

Animals↗

PubMed2000

Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: thermal behavior and phase transformation of human tooth enamel and dentin after irradiation by CO2 laser.

Acute trauma or trauma associated with occlusal disharmony can produce tooth crack or fracture. Although several methods are proposed to treat the defect, however, the prognosis is generally poor. If the fusion of a tooth fracture by laser is possible it will offer an alternative to extraction or at least serve as an adjunctive treatment in the reconstruction. The responses of soft tissues to lasers of different wavelengths are fairly well known, but the reactions of hard tissues are still to be understood. The purpose of this research was to study the feasibility of using a medium energy continuous-wave CO(2) laser and a low melting-point bioactive glass to fuse or bridge tooth fractures. The present report is focused on the first part of the research, the analysis of changes in laser-irradiated human tooth enamel/dentin by means of X-ray diffractometer (XRD), Fourier-transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). After CO(2) laser irradiation, there were no marked changes in the X-ray diffraction pattern of the enamel when compared to that before laser treatment. However, a small peak belonging to alpha-TCP appeared at the position of 2theta=30.78 degrees C. After being treated with CO(2) laser, the dentin showed much sharper peaks on the diffraction patterns because of grain growth and better crystallinity. alpha-TCP and beta-TCP were identified after laser treatment. In the FTIR analysis, an HPO(4)(-2) absorption band was noted before laser treatment disappeared after the irradiation. No significant change in the absorption band of HPO(4)(-2) was found on the FTIR curves of enamel after laser treatment. The results of DTA/TGA indicated that loss of water and organic materials occurred in both enamel and dentin after laser treatment. Under SEM, melting and resolidification occurred in both enamel and dentin by medium energy of CO(2) laser. This implies that using a continuous-wave CO(2) laser of medium energy density to fuse a low melting-point bioactive glass to the enamel/dentin is possible. We believe these phase changes and thermal data can make a useful guide for future studies on the thermal interaction and bridging mechanism between the bioactive glass and enamel/dentin under CO(2) laser irradiation.

Journal Article↗

PubMed1990

Coronary excimer laser angioplasty: reduced complications and indium-111 platelet accumulation compared with thermal laser angioplasty.

The relative safety and thrombogenicity of pulsed excimer and thermal laser angioplasty systems were compared in 20 normal coronary artery segments in a total of seven pigs. Using similar over the wire catheter systems and laser delivery periods of 3 to 5 s, thermal laser angioplasty was achieved with a 1.3 mm metal probe heated with 10 W of continuous argon laser energy and excimer laser angioplasty was performed with a 4.5F excimer laser catheter consisting of 13 concentrically arranged 200 microns fiber optics delivering 35 to 40 mJ/mm2 of xenon chloride (308 nm) excimer laser irradiation at a repetition rate of 25 to 30 Hz and a pulse duration of 120 ns. On angiography, the incidence of vessel perforation (1 in 10 versus 3 in 10) and abrupt vessel closure (0 in 10 versus 2 in 10) was less with excimer compared with thermal laser angioplasty. Macroscopically, there was a greater incidence of mural and occlusive thrombus formation after thermal laser than after pulsed excimer laser angioplasty. Histologic examination confirmed that this thrombogenicity was associated with greater charring and coagulation necrosis of the media. Quantitative indium-111-labeled platelet deposition was significantly increased after thermal laser angioplasty (median 87.2 x 10(6)/cm length) compared with excimer-treated (0.4 x 10(6)/cm length) or control (1.2 x 10(6)cm length) segments (p less than 0.001). Thus, excimer laser angioplasty was found to result in fewer complications and, as a consequence, less thrombosis and platelet accumulation than did thermal laser angioplasty.

Angioplasty, Balloon, Coronary↗

PubMed2004

Preliminary report of endolaryngeal and endotracheal laser surgery of juvenile-onset recurrent respiratory papillomatosis by Nd:YAG laser and a new fiber guidance instrument.

OBJECTIVES: Recurrent respiratory papillomatosis (RRP) caused by human papilloma virus (type 6 and 11) is the most common benign neoplasm of the larynx in children. Despite being a benign disease, treatment is very difficult and is characterized by frequent recurrence, spread throughout the respiratory tract, and malignant degeneration. Besides surgical resection and the established CO(2) laser treatment, laser surgery by fiber-guided Nd:YAG laser light promises to be a bloodless and effective treatment procedure. To improve this new method, a novel fiber guidance instrument has been developed to aid in endolaryngal laser surgery of RRP. Study design and setting The method described uses a specially designed instrument for fiber guidance that is equipped with a bendable distal tip to move the fiber end precisely. Moreover, the instrument includes an additional channel for the suction of smoke and pyrolysis products. Up to now, 5 patients (aged 4 to 8 years) with RRP were treated by Nd:YAG laser light (lambda = 1064 nm; power, 10 W; irradiance, 3.5 kW/cm(2), continuous wave) with a prototype version of the new instrument and were followed up for 12 months each. RESULTS: Because of the adequate length and the bendable distal tip with a range of -5 degrees up to 45 degrees to the optical axis of the fiber and less than 10% light loss at maximal deflection, RRP can be treated by Nd:YAG laser light easily and precisely. The continuous suctioning ensured an optimum view of the operating field and a minimal load of potential infectious laser plume and toxic pyrolysis products for the patient as well as for the physician. The laser treatment of RRP with the new fiber guidance instrument was only minimally traumatic. During 1-year follow-up visits, all Nd:YAG laser light-treated patients, showed a regression of the disease. CONCLUSIONS: The new fiber guidance instrument enables a precise and easy treatment of the RRP with fiber-guided laser systems (eg, Nd:YAG-, diode-, and KTP-lasers) and an effective removal of infectious laser plume as well as toxic pyrolysis products. A follow-up period of 1 year revealed that Nd:YAG laser surgery seems to prevent a rapid recurrence of juvenile respiratory papillomatosis in the treated patients.

Child↗

PubMed1987

Low-energy linear-incision neodymium: YAG laser iridotomy versus linear-incision argon laser iridotomy. A prospective clinical investigation.

When the Q-switched neodymium: YAG (Nd: YAG) laser is focused through the Wise 103-diopter (D) iridotomy-sphincterotomy lens (103-D lens) at low energy levels, the peripheral iris fibers can be cut individually across the iris tension lines to produce large iridotomies of controllable size. Thirty patients had linear-incision Nd:YAG laser iridotomy in one eye and linear-incision argon laser iridotomy in the other. Two-hour post-laser IOP rises averaged 7.33 mmHg for the Nd:YAG laser and 8.64 mmHg for the argon laser. The argon laser produced lens burns in 9 of 30 eyes, including 7 of 9 blue eyes. No lens damage occurred with the Nd:YAG laser. No corneal or retinal damage was seen with either laser. Local oozing of blood inhibited optical breakdown and required a pause before completion in 5 of 30 eyes with Nd:YAG iridotomy, including 4 of 6 dark brown thick irides. Because the iris fibers must be cut by direct contact with the laser plasma, serial cutting of iris fibers by multiple low-energy plasmas is safer than a single-shot, high-power plasma occupying the full thickness of the iris. Because it is effective and because it avoids the hazards of argon laser iridotomy and of high-power Nd:YAG laser iridotomy, linear incision Nd:YAG laser iridotomy is recommended as the safest method of iridotomy.

Argon↗

PubMed2002

Flashlamp pulsed dye laser and argon-pumped dye laser in the treatment of port-wine stains: a clinical and histological comparison.

BACKGROUND: Port-wine stains (PWS) are congenital vascular malformations occurring in 0.3% of children. The pulsed dye laser is a well established treatment for PWS. OBJECTIVES: To compare, clinically and histologically, the effects of the flashlamp pulsed dye laser with the argon-pumped dye laser in the treatment of PWS. METHODS: Thirty patients were treated on two to four test areas with both laser types using different energy fluences. A flashlamp pulsed dye laser with 0.45 ms pulse duration and a spot size of 5 mm was compared with an argon-pumped dye laser, with a spot size of 1 mm delivered with a robotic scanning laser handpiece (Hexascan) and 70-190 ms pulse duration. Both were tuned to 585 nm. Twelve weeks later the degree of lightening was evaluated and biopsies were taken. To count the vessels the skin sections were stained with CD34 using an immunohistochemical technique. The vessels were divided into three groups by diameter (d): d < 10 microm, 10 < or = d < 20 microm, d > or = 20 microm. RESULTS: The clinical results showed a significantly better lightening using the flashlamp pulsed dye laser than with the argon-pumped dye laser. The histological results showed a significant decrease in the number of vessels of diameter larger than 20 microm in treated compared with untreated lesions. We found no histological difference in the number of vessels between the two laser treatments. However, there was a tendency towards more small vessels (diameter < 10 microm) after one treatment with the flashlamp pulsed dye laser compared with untreated PWS. CONCLUSIONS: The flashlamp pulsed dye laser is clinically superior to the argon-pumped dye laser in the treatment of PWS.

Adolescent↗

PubMed1999

Combined laser resurfacing with the 950-microsec pulsed CO2 + Er:YAG lasers.

INTRODUCTION: Laser resurfacing with the 950 microsec pulsed CO2 laser has been proven to be efficacious in improving photodamaged skin and acne scarring. Unfortunately, prolonged erythema and delayed wound healing are common adverse sequelae, which require intensive patient education and intervention. These adverse effects may be due to the degree of nonspecific thermal damage present after resurfacing with the CO2 laser. Since erbium: YAG (Er:YAG) laser vaporization leaves far less thermal damage, it is hypothesized that its use after CO2 laser resurfacing will decrease the extent of nonspecific damage and result in improved wound healing. METHODS: Ten patients were randomized to receive laser resurfacing of one-half of the face with the 950 Msec pulsed CO2 laser with 3 passes at 300 mJ, utilizing the computer pattern generator (CPG) at settings of 596, 595, 584, and the other half of the face (randomly chosen) resurfaced with the 950 Msec pulsed CO2 laser 2 passes with the CPG at 300 mJ at settings of 596 and 595, followed by 2 passes with the Er:YAG laser (Derma-20 or Derma-K, ESC Medical Systems, Inc., Needham, MA) with a 4 mm diameter spot size at 1.7 J (approximately 14 J/cm2). Patients were evaluated in a "blinded" manner clinically and histologically before resurfacing, immediately after resurfacing, 2 to 3 days postoperatively, 1 week postoperatively, and, 4 to 8 weeks postoperatively. RESULTS: There was slightly less inflammation with the CO2/Er:YAG-treated patients. The epidermis re-formed 1 to 2 days faster with combination (UPCO2)/Er:YAG treatment than with UPCO2 laser treatment alone. In 7 of 10 patients, Er:YAG erythema resolved within 2-3 weeks with CO2 x 3 erythema persisting at the 8-week follow-up period in all patients. Three of 10 patients had no difference in the degree of erythema between the 2 treatment areas. Clinical findings correlated with histologic findings of vascularity. There was no difference in the extent or time of edema between techniques. The usual demarcation line between cheek and neck at the mandibular angle was less apparent when the UPCO2/Er:YAG combination was used. Two of 10 patients noted quicker healing with the combination laser technique. CONCLUSION: Treating a patient with the Er:YAG laser after treatment with the UPCO2 laser results in a decreased incidence of adverse sequelae without a noticeable difference in the degree of wrinkle improvement.

Erythema↗

PubMed1999

Laser resurfacing of the neck with the combined CO2/Er:YAG laser.

BACKGROUND: Several clinical studies on laser resurfacing on the neck have yielded variable results with adverse sequelae of hypopigmentation and scarring using the CO2 laser. The Er:YAG laser on the neck resulted in an improved appearance with no adverse sequelae. The combined CO2/Er:YAG laser is a laser that combines a low fluence CO2 laser with the Er:YAG laser in a near simultaneous beam. OBJECTIVE: To study the effects of the CO2/Er:YAG laser on the neck. The decreased nonspecific thermal damage of the CO2/Er:YAG laser should result in decreased postoperative erythema and improved wound healing. METHODS: Eleven patients were treated with the CO2/Er:YAG laser on the neck as well as the face at identical settings. The face was treated with four passes while the neck was treated with two passes. The patients were evaluated for the first 2 weeks then 3-6 months postoperatively. Patients were asked about treatment satisfaction and improvement in skin texture and color using a 25% scale. Skin texture and color, as well as improvement in wrinkling and adverse results were judged by a dermatologist using a 0-4 scale. RESULTS: Moderate improvement was seen in skin color while a higher degree of improvement was seen in skin texture and wrinkling in all 11 patients. No adverse sequelae, including hypopigmentation or scarring, were observed. The majority of patients had a 75-100% improvement in skin texture and color in addition to a 75-100% overall satisfaction rating. CONCLUSIONS: There is a higher degree of overall patient satisfaction, as well as improvement in skin texture and skin color, compared to patients treated with the Er:YAG laser alone. The CO2/Er:YAG laser is a highly effective laser for neck resurfacing with no adverse sequelae to date.

Adult↗