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.     

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.     

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.     

Skin resurfacing of facial rhytides and scars with the 90-microsecond short pulse CO2 laser. Comparison to the 900-microsecond dwell time CO2 lasers and clinical experience

BACKGROUND: Carbon dioxide lasers that produce either short pulses or scanned continuous beams have been used for skin resurfacing to improve wrinkles or scars. Using a high peak power, short pulse CO2 laser can produce clinically effective results with minimal thermal damage. OBJECTIVE: To evaluate the effectiveness of skin resurfacing using the 90-microsecond pulse duration CO2 laser compared to other laser systems. Erythema, healing time, complications, and histological measurement of the depth of ablation and thermal damage per pass with this system were also assessed. METHODS: Forty-one patients with facial rhytides and scars underwent resurfacing with a 90 microseconds pulse duration CO2 laser. Using patient survey, patients were evaluated for effectiveness of therapy, healing time, and complication rates. Comparisons of histologic and clinical findings were made with different short pulse CO2 lasers. RESULTS: Healing time, duration of erythema, and post-operative pain were less with the 90 microseconds pulse CO2 laser than with the 900-microsecond dwell time and 950-microsecond pulse duration lasers, while effectiveness was comparable. Complications were few with the 90-microsecond pulse laser, including three patients (9.1%) developing hyperpigmentation. One pass with the 90-microsecond pulse duration CO2 laser produced 100 microns of ablation with 17 microns of thermal damage. Ablation and damage were additive so that, by six passes, ablation depth was 350 microns and depth of thermal damage was 63 microns. This thermal damage is less than that reported with lasers having a longer pulse duration or dwell time with comparable depths of vaporization. CONCLUSION: Treatment with the 90-microsecond pulse duration laser results in a more rapid healing time and shorter duration erythema. The clinical improvements in wrinkles and sun damage were comparable. The 90-microsecond pulse duration laser provides an effective, predictable, and safe means of improving facial rhytides and scars.     

Carbon dioxide laser resurfacing. Long-term follow-up in 2123 patients

Carbon dioxide (CO2) laser resurfacing has become increasingly popular as a method of facial rejuvenation, enabling the surgeon to repair sun-damaged skin, wrinkles, and acne scars precisely. This article presents the results of the authors' histologic studies with all of the current CO2 laser systems as well as the conclusions of her experience with 2123 patients over a 5-year period. Improvements obtained from CO2 laser resurfacing appear to be long lasting, especially when combined with other procedures, and it is likely that laser resurfacing will remain in the armamentarium of facial rejuvenation for some time.     

CO2 laser conization for cervical intraepithelial neoplasia grade II-III: complications and efficacy

PURPOSE: Functional outcome after anterior resection for rectal cancer is improved by colonic J-pouch reconstruction compared with straight anastomosis. The indications for colonic J-pouch reconstruction have yet to be determined. Therefore, we attempted to determine the level at which J-pouch reconstruction provides an advantage over straight anastomosis. METHODS: A total of 48 patients who underwent 5-cm colonic J-pouch reconstruction (J-pouch group) and 80 patients who underwent straight anastomosis (straight group) underwent functional assessment one year postoperatively. RESULTS: The functional outcome in the J-pouch group was significantly better than that in the straight group when the distance of the anastomosis from the anal verge was less than 8 cm. The difference was particularly obvious when the level of the anastomosis was below 4 cm. However, functional outcome in the straight group when the anastomosis was between 9 and 12 cm from the anal verge was also satisfactory and did not differ from that in the J-pouch group when the anastomosis was between 5 and 8 cm from the anal verge. CONCLUSIONS: Colonic J-pouch reconstruction is indicated when the distance of anastomosis from the anal verge is less than 8 cm, and it is essential when the distance is less than 4 cm.     

A comparison of the results of KTP and CO2 laser stapedotomy

Allogenic hematopoietic stem cell transplantation is associated with a severe complication induced by the T-cells present in the graft: graft-vs-host disease (GVHD). While effectively preventing GVHD, ex vivo T-lymphocyte depletion of the graft unfortunately increases graft rejection and reduces the graft-vs-leukemia (GVL) effect. The ex vivo transfer to the herpes simplex thymidine kinase (HS-tk) suicide gene into T-cells before their infusion with the hematopoietic stem cells should allow for selective in vivo depletion of these T-cells with ganciclovir (GCV) if subsequent GVHD was to occur. In patients not experiencing GVHD, and therefore at a higher risk of relapse, one could preserve the beneficial effects of the donor T-cells on tumor control. Lastly, the early presence of donor T-cells in all patients should contribute to successful engraftment. We have demonstrated that retroviral-mediated transfer of HS-tk and Neomycine resistance genes in T-lymphocytes, followed by G418 selection, results in T-cells specifically inhibited by GCV with no bystander effect. In a phase I study, escalating amounts of HS-tk expressing T-cells will be infused in conjunction with a T-cell depleted marrow graft to allogenic HLA identical recipients. Toxicity, survival, alloreactivity and GCV-sensitivity of the gene-modified cells will be monitored. If successful, such an approach could significantly contribute to expanding the use of alloreactivity as a treatment modality.     

Histologic effects of the high-energy pulsed CO2 laser on photoaged facial skin

To delineate the histologic effects of laser resurfacing at photoaged skin, a protocol was designed to biopsy laser test sites in conjunction with adjacent actinically damaged skin at the time of rhytidectomy. Five patients with photodamaged skin underwent resurfacing of the preauricular region to examine the effect of increasing pulse energy and increasing number of passes on depth of dermal penetration. Histologic examination of these specimens showed that the depth of laser injury was dose-dependent. Increasing pulse energy created a deeper wound, and increasing the number of passes similarly produced a larger band of necrosis. Ten patients with photodamaged skin underwent resurfacing of the preauricular region 15 days to 6 months prior to undergoing a rhytidectomy. A comparison of the laser-resurfaced test spot with the adjacent untreated photodamaged skin demonstrated consistent histologic changes to both epidermis and dermis in all specimens examined. Following laser resurfacing, epidermal atrophy and atypia were eliminated, and all specimens exhibited a regeneration of epithelium that was normal in its morphology. Melanocytic hypertrophy and hyperplasia were corrected following treatment, although density and function of epidermal melanocytes appeared normal. All specimens exhibited a substantial amount of neocollagen formation involving both the superficial and middermis following resurfacing. In association with new collagen development within the dermis, there was noted to be a similar degree of proliferation of elastic fibers, as well as a diminution of glycosaminoglycans, which are typically present in actinically damaged elastotic dermis. To determine the effect of laser resurfacing on-black skin, laser test spots were placed in the postauricular region of three black patients. Biopsy of these test sites showed that the histologic effects of laser resurfacing were similar to those observed in Caucasian patients, with complete repopulation of epidermal melanocytes in specimens biopsied 3 months following resurfacing. The histologic effects of laser resurfacing are microscopically similar to those of phenol peeling in terms of the amelioration of photodamage. The distinction between these two treatment methods lies in their apparent effect on epidermal melanocytes, which appear to function normally following laser resurfacing.     

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.     

Complications of cutaneous laser resurfacing: a nursing guide

The neurological outcome of 146 patients who survived spinal cord injury in a neurosurgical hospital of a developing country, were compared to those reported from Stoke Mandeville, UK. The average recuperation in the two groups was similar.     

Use of Biobrane after laser resurfacing

BACKGROUND: Laser skin resurfacing has become an ever more popular and effective technique for the treatment of photoaged skin. Often a prolonged postoperative healing period adversely affects patients and physician satisfaction. Erythema and a certain degree of patient discomfort are often believed to be inevitable as they are thought to reflect depth of wounding and consequently the efficacy of wrinkle removal. In addition, a high incidence of irritant contact dermatitis has been observed, complicating recovery. OBJECTIVE: To develop a simplified wound dressing protocol aimed at achieving mild, short-term erythema and minimal side effects following effective rhytidectomy performed by laser resurfacing. METHODS: In a retrospective study from September 1995 to May 1997, 85 patients undergoing laser resurfacing for rhytid removal were placed on a postoperative wound care protocol consisting of immediate postsurgical once-only application, for 6 days, of Biobrane, a biosynthetic semipermeable dressing followed by the topical use of only a 10% cartilage extract in ointment. RESULTS: Thirty-eight full-face/three-quarter face, 26 supralabial, 13 perioral, and eight lower eyelid/crow's feet cosmetic units were treated. The fine and course wrinkles were improved in most patients, comparing favorably with other reported series. In 94% of patients erythema was absent to light pink at 4 weeks. Mild pain necessitating a medication was used in only five patients. Twenty-six patients developed transient hyperpigmentation and three patients developed focal hypopigmentation. Delayed irritant contact dermatitis presented in three patients. No infections developed and no scarring was observed. CONCLUSION: With this wound healing protocol, carbon dioxide laser skin resurfacing can effectively improved facial rhytids with minimal to insignificant erythema or discomfort.     

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.     

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.     

CO2 laser surgery in osteomyelitis

Spirituality is a critical component of the holistic mind-body-spirit model embraced by Hospice. Hospice chaplains, as part of the caregiving team, must understand their abilities and limitations in providing spiritual guidance to others who may differ in religious and spiritual beliefs.     

Endoscopic application in aesthetic and reconstructive facial bone surgery

Twenty-three cases of endoscopically assisted facial bone surgery were performed over the past 3 years. Our series is consistent with 16 cases of aesthetic contouring surgery and 12 treatments of facial bone fracture, including three cases for recontouring of frontal bone, three cases for recontouring of zygoma, endoscopically assisted correction of three zygomatic and blowout fractures, four cases for rhinoplasty and septoplasty for deviated nose, and three cases for mandible contouring surgery. To accomplish this technique, a rigid 4-mm, 30-degree down-angled endoscope was used. The frontal bone or zygomatic arch was approached endoscopically through two or three small incisions on the frontal or temporoparietal scalp. All endoscopic instruments were then manipulated through these incisions. The approach for endoscopically assisted rhinoplasty is the same as with standard rhinoplasty procedures. The approach for zygoma complex and maxillary sinus needs an intraoral incision. Recontouring of zygoma, mandible, and nasal dorsum by an air-driven burr and rasp was performed with endoscopic visual assistance. A plate and screw fixation for zygomatic arch fracture requires an additional small skin incision over the plate for the trocar method. The duration of follow-up ranged from 6 months to 30 months. The postoperative course was satisfactory with a few complications. The extra time needed for the endoscopic procedures was less than 1 hour. Endoscopically assisted facial bone surgery can be performed with adequate visualization and direct manipulation of all facial bones. Complications usually associated with extensive incisions in the bicoronal approach may be avoided. Poor visualization in the conventional approach for operation of orbit, nose, maxillae, and mandible may be avoided by use of the endoscope. This technique may prove to be ideal for aesthetic surgery for facial skeleton with smaller scar and less morbidity.     

The Q-switched neodymium (Nd):YAG laser with quadruple frequency. Clinical histological evaluation of facial resurfacing using different wavelengths

The ovariectomized (OVX), lactating rat model has been used to investigate the skeletal effects of the plant estrogen, genistein, over a 14-day period. The OVX, lactating rat on a low-calcium diet loses slightly more than 50% of its bone mineral mass during the first 2 weeks of lactation, and we have demonstrated that estrogen treatment can significantly reduce the loss of femoral mass (ash weight). Following OVX, the rats were assigned to treatment or control groups (both placebo and positive control with estrogen replacement). The treatment groups received one of three doses of a genistein-rich preparation each day via the feed for 2 weeks, after which time the pups began to have an interest in solid feed. A positive control group received conjugated estrogen in the feed. The genistein doses were: low (0.5 mg/d); intermediate (1.6 mg/d); and high (5.0 mg/d). Measurements included ash weights of the femur, scanning electron microscopy (SEM) of the proximal tibia, and uterine weights. SEM results were as follows: (1) at the low dose genistein was approximately equally effective to estrogen in the retention of cancellous bone tissue, as reflected in the number and density of trabeculae in hemisections of the tibial subepiphyseal region, but at high doses genistein was less effective; and (2) rats treated with low-dose genistein, like estradiol, had rougher endosteal surfaces and smaller pores on these surfaces than untreated control rats. Mean ash weights of the entire femur were highest in the rats treated with the low dose compared to control rats (P < 0.05), and they were higher than ash weights of rats administered the intermediate or high doses of genistein. The mean ash weights of the femurs were consistent with the genistein effects on the tibias observed by SEM. In summary, a biphasic response to the genistein preparation was found in this OVX rat model. Interpretation of the results suggests that, at the low dose, genistein appears to be an agonist at the estrogen receptor locus, whereas at higher doses the genistein is less effective and may even have adverse effects on bone cells. These findings of a biphasic effect of genistein (i.e., an inverted U effect) are consistent with those of other recent reports in the literature on isolated bone cells and on reproductive tissues. In summary, lower doses of genistein from soy foods would be expected to act similarly to estrogens with a beneficial effect on bone tissue, but at high doses that are unlikely to be consumed in human diets, this soy derivative may have potentially adverse effects on bone cell functions and thereby on bone tissue.