Pulsed Carbon Dioxide Laser Research Articles

Infections Complicating Pulsed Carbon Dioxide Laser Resurfacing for Photoaged Facial Skin

With proper technique and instrumentation, laser resurfacing for facial wrinkles has been found to be highly effective and relatively safe. Most, if not all, of the noninfectious complications such as pigmentary changes, scarring, and persistent erythema can either be avoided or managed with appropriate therapy. Postoperative infections, on the other hand, may develop despite proper technique and instrumentation. Without proper management, they may cause significant physical morbidity and psychological distress defying the expected benefit of the procedure. To quantify the incidence and to study the characteristics of infections arising after laser resurfacing for facial wrinkles with pulsed carbon dioxide laser treatment. A retrospective study was carried out by reviewing the records of all patients undergoing laser resurfacing for facial wrinkles from January 1, 1995 to April 30, 1996. An infection is defined as a positive culture in the presence of signs or symptoms of an infection. Over 16 months, 395 procedures were performed and 17 cases of culture-proven infection recorded, an incidence of 4.3%. All patients had symptoms starting between days 2 and 10 after the operation. Over half of the patients had multiple infections with two to three microorganisms. Pseudomonas aeruginosa was the most common causative agent, found in 41% of all infected cases, followed by Staphylococcus aureus (35%), S. epidermidis (35%), and Candida species (24%). Multiple drug-resistant, gram-negative bacteria were found in four cases, implicating the possibility of hospital-acquired infections. Almost all isolates of gram-positive bacteria were resistant to both erythromycin and penicillin, but not oxacillin. With proper treatment, most patients healed normally. Only one patient had persistent, multiple atrophic scars due to locally disseminated herpes simplex infection despite proper prophylaxis and treatment. Postoperative infection is uncommon and manageable with early recognition and proper treatment. The types of infectious agents being found are very similar to those reported in burn patients. This complication has been found to be much more common in patients undergoing full face resurfacing and those using a bio-occlusive dressing postoperatively. With comprehensive preventive and management measures, it is likely that this type of uncommon, yet distressful, complication can be avoided and more successfully treated. Recommendations are made for prevention and management of suspected postoperative infections.

Quantitative analysis of the interference pattern: Willison analysis, spectral analysis and integrated EMG — a comparison

Objectives: Cortical potentials evoked by carbon dioxide laser pulses have been applied in clinical practice to study nociceptive pathways for several years. In this study, we evaluate the properties of an infrared laser (thulium-YAG) with a penetration depth in the skin that matches the intracutaneous depth of nociceptors.Methods: Temperature measurements and modelling showed that the thulium laser generates painful intracutaneous temperatures with less surface heating than the carbon dioxide laser and with no side effects (up to 600 mJ pulse energy). To develop clinical evaluation criteria, laser-evoked potentials (LEPs) were recorded from 3 midline positions (Fz, Cz, Pz) versus linked earlobes in 23 healthy subjects. Within a session, two skin areas were studied twice in a balanced sequence using randomized interstimulus intervals and two intensities in randomized order.Results: After hand and foot stimulation with 540 mJ pulses, all subjects showed reproducible biphasic vertex potential, consisting of a negativity (hand: 210 ms, foot: 250 ms) and a positivity (hand: 330 ms, foot: 380 ms). Mean habituation of the vertex potential amplitude across runs was 25% (hand) or 16% (foot); due to the balanced sequence it did not affect the other comparisons. Following foot stimulation, peak latencies were significantly longer (by 40–50 ms) and amplitudes were significantly smaller than following hand stimulation (22.5±6.7 vs. 30.3±10.9 μV, mean±SD). Using 2.5 standard deviations from the mean as a cut-off, absolute normative values were determined for peak latencies and amplitudes. In addition, relative normative values were determined for paired comparisons (hand–hand, foot–foot, hand–foot).Conclusions: The thulium-YAG laser is a useful tool for assessment of impaired pain sensitivity. Representative case reports illustrate that unlike for early SEP components, the most frequent LEP abnormalities were amplitude differences.

Ultrapulse Carbon Dioxide Laser Rejuvenation of Facial Wrinkles and Scars

The ultrapulsed (high energy, pulsed) carbon dioxide lasers have been shown to be extremely useful for resurfacing facial wrinkles due to actinic damage as well as acne scars, linear postsurgical and posttraumatic scars, and exophytic skin lesions. These lasers have some advantages over skin peeling and dermabrasion, and may be combined with other procedures, especially endoscopic forehead-lifting, laser blepharoplasty, neck liposuction, and platysmaplasty. Since 1992, 1643 patients have been treated with the ultrapulsed carbon dioxide laser. Excellent results have been achieved in patients with fine wrinkles, exophytic skin lesions, and linear postsurgical and posttraumatic scars. Acne scarring patients achieved fair to good results. Complication rate was low.

A critical appraisal of high-energy pulsed carbon dioxide laser facial resurfacing for acne scars.

Thirteen patients with mild and severe acne scarring have been treated with the Ultra Pulse carbon dioxide laser over a 24-month period. Nine patients had full-face and 4 patients had regional reurfacing. All patients were pretreated with a Retin-A preparation. The patients healed in an average of 7.3 days and erythema was gone in an average of 7.6 weeks. Eight patients with mild acne experienced a good (1 patient) or excellent (7 patients) result. Of the 5 patients with severe acne characterized by marked irregularity, deep defects, and atrophy, 2 patients experienced fair results and 2 experienced good results (1 patient was lost to follow-up). Thus, laser resurfacing for severe atrophic acne achieves only moderate results, while treatment for mild acne can provide excellent results.

Treatment of facial rhytides with a high-energy pulsed carbon dioxide laser.

Facial rhytides are a common problem that often presents for treatment. Because of the tendency for rhytides to involve delicate tissue areas, traditional treatment modalities have been limited by complications of scarring or pigmentary alterations. With the advent of the new-generation high-energy pulsed carbon dioxide lasers, skin requiring resurfacing can now be treated successfully with minimal risk and side effects. This study included 259 patients with facial rhytides (104 perioral, 83 periorbital, 53 glabellar, and 17 forehead). Each patient received treatment with a high-energy pulsed CO2 laser system, and individual responses were evaluated independently by two blinded assessors at 1, 4, 8, 12, and 24 weeks postoperatively. While clinical response rates were uniformly excellent, they varied in different locations. On average, there was a 90 percent improvement in all areas under study. The periorbital regions responded best, an average 93 percent improvement being seen. The facial rhytides with the lowest response rates (86.8 percent) were those which were most severe and those caused by excessive muscle movement (i.e., frown lines at the glabella). No incidences of scarring were noted, but erythema persisting 1 to 3 months (mean 2.2 months) following laser irradiation was typical. Transient postinflammatory hyperpigmentation of 3 months' average duration was seen in 30 percent of patients and was not limited to those individuals with darker skin tones. The high-energy pulsed carbon dioxide laser is a safe and effective treatment for facial rhytides. Treatment can be delivered in an outpatient setting without the need for general anesthesia, and preliminary evidence suggests long-lasting results.

Pulsed carbon dioxide laser resurfacing of photo-aged facial skin

Pulsed carbon dioxide laser resurfacing of photo-aged facial skin

Comparison of Two High-Energy, Pulsed Carbon Dioxide Lasers in the Treatment of Periorbital Rhytides

Carbon dioxide (CO2) laser technology has expanded over the past 20 years from the production of precise excisional and cutting instruments to the recent development of high-energy, pulsed systems that allow for controlled tissue vaporization. These newest lasers permit removal of thin layers of skin with minimal damage to normal adjacent skin structures. The precise and reproducible nature of tissue destruction has led to a resurgence of interest in cutaneous resurfacing. To compare the clinical effectiveness, side effect profile, and postoperative course of two different high-energy, pulsed CO2 lasers (ultrapulse and surgipulse) in the treatment of periorbital rhytides. Ten patients with moderate to severe periorbital rhytides received laser treatment using the surgipulse CO2 laser on one side and the ultrapulse CO2 laser on the opposite periorbital region. Equivalent laser parameters and treatment conditions were used with both systems. Sequential clinical analyses were performed independently by two blinded assessors. In addition, optical profilometry measurements of silicone rubber skin surface casts were obtained before and after laser irradiation to determine skin texture changes. There was a 63% average clinical improvement of periorbital rhytides following surgipulse laser treatment and a mean improvement of 82% after ultrapulse laser irradiation. Skin surface texture in all laser-treated rhytides approximated those found in normal skin. An increased number of laser passes were required using the surgipulse system to effect the same clinical endpoints as the ultrapulse system. While both the surgipulse and ultrapulse high-energy CO2 laser systems can effectively improve periorbital rhytides, the ultrapulse system provides a slightly enhanced clinical response with fewer passes, presumably due to improved tissue vaporization.

Pulsed carbon dioxide laser, trichloroacetic acid, Baker-Gordon phenol, and dermabrasion: a comparative clinical and histologic study of cutaneous resurfacing in a porcine model

Pulsed carbon dioxide laser, trichloroacetic acid, Baker-Gordon phenol, and dermabrasion: a comparative clinical and histologic study of cutaneous resurfacing in a porcine model

Pulsed Carbon Dioxide Laser, Trichloroacetic Acid, Baker-Gordon Phenol, and Dermabrasion: A Comparative Clinical and Histologic Study of Cutaneous Resurfacing in a Porcine Model

Recent advancements in carbon dioxide laser technology have allowed the development of microsecond-domain pulses with a high pulse energy (up to 500 mJ), enabling precise and complete tissue vaporization while minimizing residual thermal damage and its potential adverse effects on wound healing.¹For appropriate clinical application, one should know the depth of vaporization and residual thermal damage after successive laser passes over the same area, the depth of vaporization and residual thermal damage caused by different pulse energies, and how these in turn compare with the depth of tissue removal afforded by currently used resurfacing modalities: dermabrasion, 35% trichloroacetic acid peel, and Baker-Gordon (50%) phenol peel. To evaluate these immediate tissue effects and postoperative wound healing for all of these modalities, a clinical and histologic animal study was performed. <h3>Materials and Methods.</h3> A grid that delineated 16 treatment sites measuring 3×3 cm was tattooed onto the paravertebral area of

Pulsed carbon dioxide laser resurfacing of photo-aged facial skin

Pulsed carbon dioxide laser resurfacing of photo-aged facial skin

Pulsed Carbon Dioxide Laser Resurfacing of Photoaged Facial Skin

public demand for procedures to rejuvenate photoaged skin have stimulated the use of high-energy short-pulsed carbon dioxide lasers as a precise and predictable treatment modality. The purpose of this study was to determine the degree of clinical improvement achieved in treating perioral and periorbital wrinkles with a high-energy, microsecond-domain pulsed CO2 laser. Photodamaged skin in the perioral (n=73) and periorbital (n=38) regions was treated with multiple passes of confluent single pulses of CO2 laser energy (10 600 nm, 3-mm collimated beam, <1- millisecond pulse, 450 mJ per pulse, 2 to 5 W), with the tissue being cleansed and débrided with normal saline between passes. A nine-point clinical scoring system was devised for evaluation of the degree of wrinkling and photodamage present. Preoperative and postoperative photographs were independently scored by four ¿blinded¿ reviewers. The patients were observed postoperatively for 1 to 12 months for the course of healing, and adverse events were recorded. All three classes (mild, moderate, and severe) of photoaging of the skin responded equally well, showing an average wrinkling score reduction of 2.25 for the periorbital region and 2.34 for the perioral region, the most superficial wrinkles and photodamage being eliminated and the more severe being markedly improved. An unexpected finding was tightening of loose and folded skin. Side effects included transient erythemia and postinflammatory hyperpigmentation, and one instance of an isolated hypertrophic scar. Resurfacing of photoaged skin by means of a high-energy, microsecond-domain pulsed CO2 laser with a specific clinical treatment protocol results in predictable improvement in perioral and periorbital wrinkling and photodamage with minimal risks. Heat-induced collagen shrinkage appears to contribute to these results by tightening loose skin and folds.

Resurfacing of atrophic facial acne scars with a high-energy, pulsed carbon dioxide laser.

Treatment of atrophic acne scars has been limited to the use of such traditional treatments as dermabrasion and chemical peels for many years. Recently, the addition of high-energy, pulsed carbon dioxide (CO2) lasers to the treatment armentarium has created renewed enthusiasm for cutaneous resurfacing due to their ability to create specific thermal injury with limited side effects. To determine the effectiveness of a high-energy, pulsed CO2 laser in eliminating atrophic facial scars and to observe for side effects. Fifty patients with skin phototypes I-V and moderate to severe atrophic facial acne scars were included in the study. Each patient received one high-energy, pulsed CO2 laser treatment using identical laser parameters by the same experienced laser surgeon. Baseline and 1-, 4-, 8-, 12-, and 24-week postoperative photographs and clinical assessments were obtained in all patients. Textural analysis of skin before and after laser irradiation were obtained in 10 patients to confirm clinical impressions. Clinical evaluations were conducted independently by two blinded assessors. There was an 81.4% average clinical improvement observed in acne scars following laser treatment. Skin texture measurements of laser-irradiated scars were comparable to those obtained in normal adjacent skin. Side effects were limited to transient hyperpigmentation lasting an average of 3 months in 36% of patients. Prolonged erythema (2 months average) was usual and considered to be a normal healing response. No hypertrophic scarring was observed following laser treatment. High-energy, pulsed CO2 laser treatment can safely and effectively improve or even eliminate atrophic facial scars and provides many benefits over traditional treatment methods.

Laser Hair Transplantation

Micro- and minigrafting have become increasingly popular in hair transplantation over the past decade, resulting in larger numbers of grafts per session and lengthy, potentially technically difficult procedures. The advent of very high energy pulsed carbon dioxide lasers as surgical instruments has led to the investigation of their use in hair transplantation, as bloodless surgery with tissue removal by vaporization has obvious advantages as far as surgical speed is concerned. A prospective study of eight patients comparing conventional micro- and minigrafting using 18- and 14-gauge needle punctures with dilators versus laser-vaporized donor sites with variation of laser parameters was conducted with monthly evaluation of healing and hair growth for 6 months. In addition, an in vitro histological study of laser vaporization recipient sites on excised scalp tissue was conducted to evaluate the residual thermal damage of various laser parameters. The conventional micro- and minigrafts healed faster and resulted in better hair growth than the laser vaporization sites. The donor sites were judged to be comparable as far as healing, but more time consuming with the laser. The operative time for the laser recipient sites was 50% of that of the conventional sites. The clinical results of laser hair transplantation are very dependent upon the laser parameters and technique used. Though operative time may be significantly reduced, the end result clinically is dependent on proper choices of pulse parameters and technique.

Matrix Isolation/Fourier Transform Infrared Spectrometry of Laser-Desorbed Species

Initial results are presented for a novel experimental arrangement which allows the successful study of laser-desorbed neutral species under matrix isolation conditions. In the current work, a pulsed carbon dioxide laser (10.6 μm) is employed for laser desorption. With the combination of a previously described cryogenic trapping technique with coaxial matrix isolation gas (xenon or argon) introduction, laser-desorbed neutrals have been matrix isolated and their Fourier transform infrared spectra recorded. Two different cinnamic acid derivatives ( p-coumaric acid and sinapinic acid) typically employed for matrix-assisted laser ionization (MALDI) mass spectrometry were utilized to demonstrate this new technique. Experimental conditions were determined for optimal matrix isolation of the laser-desorbed species. Two different desorption geometries were examined with respect to their effectiveness for matrix isolation of desorbed neutrals. A covalent dimer of p-coumaric acid produced in an external UV photoreactor and thought to be a possible photoreaction product in UV MALDI was studied by this technique. Thermal degradation of this dimer is shown to occur above threshold irradiance for laser desorption.

The Biological Effects of Carbon Dioxide Laser Surgery on Rabbit Articular Cartilage

A pulsed carbon dioxide laser made predetermined superficial and deep (subchondral) lesions through arthrotomies on the femoral condyles of adult New Zealand rabbits. Twenty rabbits, including controls, were divided into acute, 1-, 3-, 6-, and 12-month sacrifice groups. Early sacrifice groups showed some fibrous ingrowth from the deep lesions, but not the superficial lesions, and this was not seen in the 6- or 12-month groups. Cells below and adjacent to the laser lesions appeared viable when compared with controls. In each group studied, no histologic evidence of healing or fibrous covering in the superficial or deep laser lesions was found. No adverse clinical effects (synovitis, infection) were found in the laser groups, and the laser permitted excellent depth control during vaporization. However, the authors caution against irradiating articular cartilage.

Laser surgery of the nail unit.

The past decade has seen a dramatic increase in the use of lasers for the treatment of dermatologic disorders. A variety of laser systems has been found to be useful in the treatment of numerous conditions found in the nail unit. The vascular lesions of the nail unit have been treated with the pulsed dye, tunable dye, copper vapor, argon, and carbon dioxide (CO2) lasers. Pigmented lesions noted in the nail unit have been effectively treated with the Q-switched ruby, copper vapor, argon, and pulsed dye lasers. The CO2 laser has been widely used for the treatment of benign and premalignant neoplasms of the nail unit as well as inflammatory processes. Investigational lasers, such as the gold vapor and excimer lasers, may provide clinical benefits for diseases of the nail unit in the near future. The potential advantages of laser surgery of the nail unit include the selective destruction of vascular and pigmented tissue as well as precise tissue destruction.

Vasodilator flare due to activation of superficial cutaneous afferents in humans: heat-sensitive versus histamine-sensitive fibers

Histamine-sensitive nerve endings are assumed to terminate in the superficial epidermis. Heat-sensitive nociceptors that are excited by brief carbondioxide-laser pulses must also terminate within the epidermis, because this infrared radiation has an extinction length of about 10 μm. We now compared laser heat stimuli (10 W, 50 ms, 20 mm 2) with intradermal injections of histamine (10 −10 to 10 −8 mol) in their capacity to cause cutaneous vasodilatation (flare) in awake human subjects. Cutaneous blood flow was measured with a two-channel laser-Doppler device. The radiant heat pulses caused a transient cutaneous vasodilatation that spread at least 15 mm from the stimulus site. There was no visible flare and vasodilatation could only be detected by laser Doppler measurements. Although the heat pulses elicited enough nociceptor activity to be perceived as moderately painful, the magnitude of the vasodilatation was smaller and its duration shorter than after the smallest dose of histamine. In contrast, nociceptor activation by heat is usually stronger than by histamine. These data indicate that flare and pain are two different aspects of cutaneous small fiber function.

Pulsed Carbon Dioxide Laser for Cartilage Vaporization and Subchondral Bone Perforation in Horses Part II: Morphologic and Histochemical Reactions

A pulsed carbon dioxide laser was used to vaporize articular cartilage in four horses, and perforate the cartilage and subchondral bone in four horses. Both intercarpal joints were examined arthroscopically and either a 1 cm cartilage crater or a series of holes was created in the third carpal bone of one joint. The contralateral carpus served as a control. After euthanasia at week 8, the treated and control joints were examined for gross changes, and samples of cartilage and subchondral bone, synovial membrane, and peripheral lymph nodes were examined histologically. Depletion of cartilage matrix glycosaminoglycan was assessed by safranin-O histochemical staining of the laser site and adjacent cartilage. Cartilage removal by laser vaporization resulted in rapid regrowth, with fibrous and fibrovascular tissue and occasional regions of fibrocartilage at week 8. The subchondral bone, synovial membrane, and draining lymph nodes appeared essentially unaffected by the laser cartilage vaporization procedure. Conversely, carbon dioxide laser drilling of subchondral bone resulted in poor penetration, extensive areas of thermal necrosis of bone, and significant secondary damage to the apposing articular surface of the radial carpal bone.

Pulsed Carbon Dioxide Laser for Cartilage Vaporization and Subchondral Bone Perforation in Horses Part I: Technique and Clinical Results

A carbon dioxide laser, used in a rapidly pulsed mode, was evaluated for intra-articular use in horses. Under arthroscopic guidance, a lensed 5 mm laser probe attached directly to a hand-held carbon dioxide laser was inserted into one intercarpal joint of eight horses. In four horses, a cartilage crater 1 cm in diameter was created to the level of the subchondral bone of the articular surface of the third carpal bone. In four horses, the laser was directed perpendicular to the articular surface of the third carpal bone and activated to penetrate the cartilage and subchondral bone. The intercarpal joint of the opposite carpus in each horse was subjected to arthroscopic examination and insertion of the laser probe for an equivalent time. The laser was not activated and these joints served as sham operated controls. The horses were evaluated clinically for 8 weeks, then euthanatized, and the joints were examined radiographically, grossly, and histologically. Pulsed carbon dioxide laser vaporized cartilage readily but penetrated bone poorly. Cartilage vaporization resulted in no greater swelling, heat, pain on flexion, lameness, or synovial fluid reaction than the sham procedure. Laser drilling resulted in a shallow, charred hole with a tenacious carbon residue, and in combination with the thermal damage to deeper bone, resulted in increased swelling, mild lameness and a low-grade, but persistent synovitis. The carbon dioxide laser is a useful intra-articular instrument for removal of cartilage and has potential application in inaccessible regions of diarthrodial joints. It does not penetrate bone sufficiently to have application in subchondral drilling.

Deposition of MoSi 2 thin films by laser ablation from free-falling particles

Thin films of molybdenum silicides were deposited by a new method in which mixtures of small, free-falling particles are heated by focused 10.6 μm radiation from a pulsed carbon dioxide laser in an ultrahigh vacuum chamber. The composition of the resulting films was adjustable and controlled by the selection of particle sizes and their relative numbers. It was found that collecting substrates positioned in the rearward hemisphere along the direction of the laser beam had films which were nearly free of defects. Recoil pressure exerted by the affluent vapor had the tendency to drive target residue into the forward hemisphere. Compositional analysis of the deposited films was performed using Rutherford backscattering spectroscopy. The measured values of atomic concentration are consistent with surface evaporation of the particles and are in close agreement with the values calculated from the specific surface areas of the target constituents and theoretical mass evaporation rates. Laser heating of molybdenum disilicide particles was found to produce silicon-rich Mo-Si films. Auger depth profiles of residual target particles which were collected on forward substrates were enriched in molybdenum.