Cutaneous resurfacing with CO2 and erbium: YAG lasers: preoperative, intraoperative, and postoperative considerations

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.     

Fire hazards and CO2 laser resurfacing

The purpose of this study was to investigate the fire risk of laser resurfacing in the presence of supplemental oxygen. This study aims at defining safety parameters of variables such as laser energy level, oxygen flow rate, and "oxygen to laser target distance" when oxygen is delivered through a nasal cannula or nasopharyngeal tube. The typical operating room environment was simulated in the laboratory using the Yucatan minipig animal model. The energy source was a Coherent Ultrapulse CO2 laser. It was found that combustion did not occur at laser settings of 500 mJ, 50 W, 100 kHz, and a density of 5, used in conjunction with an oxygen flow rate of 6 liter/minute with the target area as close as 0.5 cm to the oxygen delivery. A total of 400 computer pattern generator treatments were delivered using this energy setting without observation of any combustion (p < 0.001). This provides evidence that while using even somewhat high laser settings and oxygen flow rate, laser induced fires can be avoided. We conclude that use of the laser in the presence of oxygen is safe, provided the target area is free of combustible fuels. Despite this assurance, laser mishaps are serious because they lead to both morbidity and mortality. It is our recommendation that close attention be constantly paid to all details, thus reducing the hazard potential of laser energy on local factors in an oxygen-rich environment.     

Erbium laser resurfacing: current concepts

Laser skin resurfacing has enjoyed great popularity in recent years with the introduction of computerized, pulsed carbon dioxide lasers. However, the morbidity and side effects of carbon dioxide lasers have stimulated a search for alternative methods of skin remodeling. The erbium:YAG laser can be successfully used for skin resurfacing, with lower morbidity than the carbon dioxide laser. In a series of 625 patients who had erbium:YAG resurfacing, the following conclusions were reached. (1) Long-term (> 6 months) improvement in wrinkles and acne scars required total fluences exceeding 20 J/cm2. Periocular wrinkles required total fluences of between 20 and 40 J/cm2, depending on the depth of the wrinkles and skin thickness. Perioral rhytids required total fluences of between 40 and 80 J/cm2, whereas the cheeks and forehead required total fluences of 30 to 60 J/cm2. (2) Deeper wrinkles were best treated with a combination of erbium and carbon dioxide lasers, which minimized the bleeding that occurs with deeper erbium resurfacing. The simultaneous combined erbium with carbon dioxide laser was particularly advantageous. (3) Complications were relatively uncommon using the scanning erbium laser, and most adverse effects occurred early in the series. Scarring occurred in 5 of the 625 patients (0.8 percent) and mostly resolved with intralesional steroids. Hyperpigmentation occurred in 21 of the 625 patients (3.4 percent) and was temporary in nature. Hypopigmentation, which became evident after 6 months, occurred in 25 of the 625 patients (4.0 percent) but was mild and not a significant cosmetic problem, except in one patient who developed scarring on the neck. Hypopigmentation seemed to be related to the depth of resurfacing. Four of the 625 patients (0.6 percent) developed temporary scleral show, but no patients had permanent ectropion. Eight of the 625 (1.3 percent) developed synechiae under the lower eyelid, which required minor correction.     

CO2 laser resurfacing of psoriatic plaques: a pilot study

We have cloned the 5' upstream regulatory region of the mouse somatostatin receptor 2 gene. Its genomic organization is novel among all somatostatin receptor genes. It contains two previously unrecognized exons, separated by introns larger than 25 kb, and three tissue and cell specific alternative promoters. The first promoter in front of exon 1 is active only in AtT-20 tumor cells. The second promoter, located 5' to exon 2, is used in brain, pituitary, adrenals, pancreas, NG 108-15 and AtT-20 cells. Furthermore, it contains putative DNA elements for regulation by glucocorticoids, estradiol and cAMP. A third promoter, located in exon 3, is additionally used in lung, kidney and spleen.     

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

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

Clinical application of the erbium:YAG laser for apicoectomy

Recently, an Er:YAG laser has attracted attention because of the possibility of cutting hard tissues with extremely small thermal effects. In this article, we report 8 cases (13 teeth) of apicoectomy using Er:YAG laser. All procedures were performed without using an air turbine or an electric drill. Although the cutting speed of this laser was slightly slower than ordinary methods, its clinical application for apicoectomy has many advantages including absence of discomfort and vibration, less chance for contamination of the surgical site, and reduced risk of trauma to adjacent tissue.     

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.     

Long-term assessment of CO2 facial laser resurfacing: aesthetic results and complications

Several series have documented the ability of the carbon dioxide laser to smooth facial rhytids; however, follow-up has been limited to several months. Since 1995, more than 600 full or partial facial resurfacings were performed with the pulsed CO2 laser. To assess the long-term efficacy and safety of this procedure, the results of 211 resurfacings were retrospectively reviewed using a custom-designed database. Variables that were input included patient demographics, Fitzpatrick skin type, smoking history, prior and concurrent facial procedures, laser pass data, and postoperative complications. Short and long-term aesthetic results were graded by a blinded panel of plastic surgery reviewers (none of whom performed the laser resurfacing) using a standardized photographic rhytid scale. For each facial region, this scale consisted of eight high-resolution photographs depicting increasingly severe wrinkling. Facial rhytids were almost completely ablated at the 3 and 6 month follow-up. Some relapse was seen at 1 year, but the overall aesthetic result remained very good. Regions with dynamic rhytids (e.g., the perioral region) showed more recurrence. The best and most durable results were seen in the cheeks. Infection and scleral show each occurred in 13 patients (6 percent). Forty-five patients (21 percent) developed postprocedure hyperpigmentation, but the overwhelming majority of this group were treated before our postoperative antipigment regimen. Hypopigmentation was noted in 17 patients (8 percent) in this early follow-up group. Two patients (1 percent) developed postoperative scarring. It is hoped that these data will serve to provide additional information on the long-term results of laserbrasion.     

Thermal injuries as a result of CO2 laser resurfacing

CO2 laser resurfacing of the face for fine wrinkles has gained great popularity over a short period of time. The use of the CO2 laser has proven to be effective in reducing or eliminating fine wrinkles. This tool in the surgeon's armamentarium has been added to those of dermabrasion and chemical peel. The theoretical advantage of the use of the CO2 laser for resurfacing has been better accuracy and reportedly more control of the depth of penetration. The use of the CO2 laser has been welcomed by many cosmetic surgeons. Until now, there have been few reported cases of complications with the use of the CO2 laser. To many, this would sound too good to be true; unfortunately, that is the case. The CO2 laser is a high-energy machine that can indeed cause thermal injury. This thermal injury can result in deep burns to the skin and hypertrophic scarring. We feel this is more common than is currently being reported, and we share our experience as a burn and wound care referral service. During an 18-month period, 20 consecutive patients were referred to our practice who had received injuries from the CO2 laser resurfacing laser. We present here in this review a summary of those injuries. The CO2 resurfacing laser is a very effective tool for the treatment of fine wrinkles, but it is not without the potential for serious complications. We urge caution with the use of the laser and prompt recognition and treatment of thermal injury to the skin.     

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

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

Laser skin resurfacing. Er:YAG laser and cw-CO2 laser with scanner system in direct comparison]

PURPOSE: To integrate a newly developed OLCR instrument into the optical system of the excimer laser. The instrument is designed to perform corneal pachymetry before, during, and after corneal photoablation and thus allow for a precise and continuous on-line measurement of the corneal photoablation process. METHODS: The conditions required to integrate the OLCR instrument into the excimer laser optics were investigated. With a technical setting providing on-line data of corneal thickness, three groups of 8-10 corneae received central keratectomies of 27 (group 1), 82 (group 2) and 163 (group 3) microns calculated central depth and 7.38 mm diameter. All measurements were performed with OLCR and ultrasound. RESULTS: The OLCR instrument was coupled into the optical system of the excimer laser and a useful signal obtained at SLD power levels of 40 microW incident on the cornea. Individual corneal thickness measurements were obtained before, during and after the photoablation procedure. In group 1, the ablation was 50.3 (40-68) microns measured with ultrasound and 30.2 (27-38) microns measured with OLCR. In group 2, the ablation was 101.1 (80-113) microns measured with ultrasound and 93.3 (76-109) microns measured with OLCR. In group 3, the ablation was 210.6 (190-227) microns measured with ultrasound and 188.4 (181-197) microns measured with OLCR. The precision (standard deviation) for measurements of individual corneas was 1-2 microns with OLCR and up to 12 mm in Ultrasound measurements. CONCLUSION: With this interferometric method, continuous, non-contact measurement of corneal thickness before, during and after excimer laser photoablation were performed. By establishing a feed-back control between the pachymetric measurements and the photoablation process, the precision of excimer ablation may possibly be further increased.     

Multicenter clinical experience using an erbium:YAG laser for vitreoretinal surgery

PURPOSE: To evaluate the advantages, disadvantages, safety, complications, and surgical applicability of an erbium:YAG laser system for maneuvers in vitreoretinal surgery. METHODS: A prospective, consecutive trial of 68 eyes in 66 patients undergoing vitreoretinal surgery in which an erbium:YAG laser with graduated output from 0.2 to 5.0 mJ per pulse, repetition rate of 2 to 30 Hz, and equipped with a flexible fiber optic and interchangeable 20-gauge intraocular fiber optic endoprobes was used to perform specific maneuvers, including transection, incision, and ablation of membranes, retinotomy, vessel coagulation, iridectomy, and lens tissue ablation. The patients were treated in five centers in contemporary vitreoretinal surgical settings for surgical indications, including proliferative diabetic retinopathy, proliferative vitreoretinopathy, epiretinal membrane, and retinopathy of prematurity. RESULTS: One hundred seventy-four maneuvers were performed with an overall surgical efficacy rating of excellent or good in 84% of maneuvers, ranging from a high of 100% for subretinal membrane transection to a low of 25% for coagulation of blood vessels. Complications included retinal break or photocoagulative injury in 5% of epiretinal membrane incisions, minor bleeding from transected retinal vessels during 29% of retinotomies, and intraocular lens damage during two posterior capsulotomies. The most significant limitation was the cautious pace used during maneuvers near the retinal surface. CONCLUSION: The erbium:YAG laser is capable of versatile new approaches offering precise tissue cutting and ablation in vitreoretinal surgical maneuvers with a high degree of safety. The main limitation encountered was the slow speed of certain critical maneuvers near the retina.     

Wound healing and soft tissue effects of CO2, contact Nd: YAG and combined CO2-Nd: YAG laser beams on rabbit trachea

Rabbit trachea was used as an experimental model to study tissue effects and healing of full-thickness tracheal lesions produced by CO2, contact Nd: YAG and combined, coaxial CO2-Nd: YAG (Combo) laser beams. Two power settings (10 W and 16 W) were used with CO2 and contact Nd: YAG lasers. Three different CO2/Nd:YAG power ratios (1:1, 1:2 and 1:4) and power settings (12 W 15 W and 16 W) were used with the Combolaser. Histological specimens for light and transmission electron microscopy were prepared immediately and 1, 3, 5, 7, 14 and 21 days postoperatively. The wound with the most precise and fastest healing was produced by contact Nd: YAG laser. CO2 laser produced a moderate amount of charring and the largest amount of coagulated tissue with a slightly prolonged healing period. In the acute phase, tissue defects produced by the Combolaser with power ratios 1:1 and 1:2 resembled the CO2 laser lesions but with slightly less charring. The power ratio 1:4 diminished the cutting properties of the beam considerably. During the healing period the Combolaser produced the most intensive inflammation and granulation tissue formation resulting in delayed regeneration of the lesion. In transmission electron micrographs the most severe damage to chondrocytes was seen after using the Combolaser. These findings indicate that the Combolaser produces deeper tissue damage than CO2 or contact Nd:YAG laser. However, the Combolaser appears to be suitable for tracheobronchial operations, owing to its good simultaneous cutting and haemostatic properties.     

Antiproliferative therapy with 5-fluorouracil in erbium:YAG laser sclerostomy ab externo

In the United States debate continues about the necessity of ventilation during CPR because of fear of contracting infectious diseases. Three questions will be considered in this article. First, is ventilation necessary for the treatment of cardiac arrest? Second, is mouth-to-mouth ventilation any better than no ventilation at all? Third, are other techniques of ventilation as effective or more effective than mouth-to-mouth ventilation during basic life support CPR? Although research is still inconclusive with regard to the need for ventilation during CPR, recent findings have clarified the effect of ventilation during low blood flow states and how ventilation influences resuscitation. Ventilation affects oxygenation, carbon dioxide elimination, and pH during times of low rates of blood flow. Ventilation may be unnecessary during the first few minutes of CPR. Under conditions of prolonged, untreated cardiac arrest, ventilation during CPR affects return of spontaneous circulation. Isolated hypoxemia and hypercarbia independently have adverse effects on survival of cardiac arrest. Because ventilation with exhaled gas contains as much as 4% CO2 and less oxygen than air, it may have adverse effects during CPR. Spontaneous gasping may provide sufficient ventilation during CPR. Chest compression alone provides some pulmonary ventilation and gas exchange. Active chest compression-decompression may improve gas exchange better than does standard chest compression. Other forms of manual ventilation may also have a role in CPR.     

Experimental erbium: YAG laser photoablation of trabecular meshwork in rabbits: an in-vivo study

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.     

Minimally invasive cardiac surgery: current status and perspective

This study investigated the features of calf deep vein thrombosis (DVT) as a pulmonary embolic source. Fifty-eight lower limbs in 29 patients who were suspected of having DVT distal to the popliteal vein were screened by ultrasonography. Then, ascending venography was performed to confirm the diagnosis. Pulmonary embolism (PE) was diagnosed in suspected patients by use of pulmonary perfusion scanning or pulmonary angiography. Venography revealed calf DVT in 33 limbs in 28 patients. Of 28 patients, six had symptomatic PE. Thrombosis was found in the muscle veins in 18 limbs, the trunk veins in 11, and both veins in four. Isolated single vein thrombosis was found in the soleal vein in 14 limbs (42%), the posterior tibial vein in eight, the peroneal vein in two, and the gastrocnemius vein in two. The overall percentage of soleal vein thrombi was 61%. All six patients with symptomatic PE had isolated soleal vein thromboses. Calf DVT was a pulmonary embolic source when isolated thrombosis of the large soleal vein was more than 7 mm in diameter. Soleal veins were the most frequent and important location of calf DVT, suggesting that these were an occasional embolic source of critical PE.