Mineral rich algae with pine bark improved pain, physical function and analgesic use in mild-knee joint osteoarthritis, compared to Glucosamine: A randomized controlled pilot trial.

INTRODUCTION: Osteoarthritis (OA) is characterised by synovial joint pain, functional disability and affects ∼13 % of people worldwide, of which ∼16-27 % report Knee-OA (KOA). Glucosamine (Glu) is the most widely used nutraceutical treatment for OA despite a lack of scientific consensus, therefore alternative nutraceutical treatments are required. The aim of this study was to investigate the effect of Lithothamnion species, seawater-derived magnesium and pine bark (Aq+) on pain, symptoms and improve physical function in symptomatic (sKOA), compared to Glu. METHODS: 358 participants were screened. In a double-blinded crossover pilot-trial, sKOA participant (n = 30) were randomly assigned to either the Glu group (2000 mg day-1) or Aq+ (3056 mg day-1) for 12 weeks (clinicaltrials.gov:NCT03106584). The Knee Injury and Osteoarthritis Outcome Score was used to assess subjective pain and symptoms. Timed-up-and-Go (TuG) and Six minute walking distance were used to assess functional change and analgesic use was recorded. RESULTS: Aq+ improved pain, with a large effect (P < 0.01, d' = 0.73, 95 %CI 0.201-1.265) and no change for Glu (d' = 0.38, P = 0.06). Only Aq+ improved pain (P < 0.05) for males (d' = 0.91, 95 %CI 0.162-1.667) and females (d' = 0.55, 95 %CI 0.210-1.299). In females, Aq+ improved TuG by -7.02 % (d' = 0.92, 95 %CI 1.699-0.141) while Glu worsened performance by 4.18 % (P = 0.04). Aq+ reduced analgesia by 71.6 %, compared to Glu (P = 0.02; d' = 0.82, 95 %CI 1.524-0.123). Aq+ was superior to Glu at improving pain, KOOS subscales, physical function and analgesia use in mild-sKOA. Given these data, Aq+ should be considered as a supplementary treatment for early-stage-KOA and may have the potential to reduce use of pain medication, although larger replication studies are required.

Gingipain enzymes from Porphyromonas gingivalis preferentially bind immobilized extracellular proteins: a mechanism favouring colonization?

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis, an anaerobic bacterium associated with adult periodontal disease, employs a number of pathogenic mechanisms, including protease/adhesin complexes (gingipains), fimbriae and hemagglutinins, to maintain attachment within colonized hosts. Here we examined the binding of gingipains and whole, live P. gingivalis cells to immobilized extracellular matrix proteins in the presence of soluble forms of the same proteins, to investigate whether this may constitute a colonization mechanism in the oral environment. MATERIAL AND METHODS: Binding of purified gingipain molecules and whole bacterial cells to immobilized matrix proteins was examined in the presence and absence of soluble competitors using enzyme-linked immunosorbent assays. RESULTS: Purified gingipains or whole, live bacteria preferentially bound immobilized forms of matrix proteins, even in the presence of soluble forms of the same proteins. Fimbriae appeared to be redundant for adhesion to immobilized proteins in the presence of the gingipains, indicating that the protease/adhesins and hemagglutinins may be more important for adhesion under these conditions. CONCLUSION: The data presented here provide evidence for a model of adhesion for P. gingivalis within the fluid environment of the oral cavity, where preferential binding of matrix-located proteins over soluble forms facilitates colonization of the host.

The gingipains from Porphyromonas gingivalis do not directly induce osteoclast differentiation in primary mouse bone marrow cultures.

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis is a major aetiological agent in the development of periodontitis, the major clinical hallmark of which is bone resorption. The cysteine proteases (gingipains) produced by P. gingivalis have a critical role in the pathogenesis of the disease, and previous studies on whole bacteria have implicated these enzymes in osteoclastogenesis, a process which serves to upregulate bone resorption. The effects of the gingipains from P. gingivalis on osteoclast differentiation were investigated here to determine whether the enzymes directly contribute to osteoclastogenesis and thus to bone resorption. MATERIAL AND METHODS: The effects of the gingipains on osteoclast differentiation were investigated in primary mouse bone marrow cultures. The cultures harvested from C57BL6/J mice were incubated in the presence of parathyroid hormone, a known osteoclastogenic factor, or active/inactivated forms of three gingipains. Osteoclast differentiation was quantified by counting the number of multinucleated cells positive for tartrate-resistant acid phosphatase, an enzyme marker for these cells. RESULTS: After 10 days of culture, the gingipains, either active or inactive, failed to stimulate osteoclast differentiation in comparison to the parathyroid hormone. CONCLUSION: The data presented here demonstrate that the gingipains do not induce osteoclast differentiation in this system, indicating that the bacterium uses other mechanisms to induce bone loss.

Weekly treatments with a burst-firing magnetic field alters behavior in the elevated plus maze after two sessions.

In a split-litter design, rats were either injected with 15 mg/kg of clomipramine or saline from postnatal Days 8 through 21. Other rats from the same litters were not injected. When the rats were 90 days of age, the rats were tested once per week for five weeks in an elevated plus maze that contained two open arms (no alls) and two walled arms. Following each test, they were exposed (total of 4 exposures) for 30 min. to a burst-firing magnetic field (1 microTesla) that has been shown to reduce depression in human beings. After two treatments, the rats exposed to the burst-firing fields spent about half the amount of time in the open arms compared to the sham-field exposed rats. The interaction between adult treatment and whether the rats had received the antidepressant before weaning was not significant statistically. These results suggest that at least two weekly sessions may be required before significant changes in behavior occur after weekly 30-min. exposures to these potentially "therapeutic" magnetic fields.

CO2 laser resurfacing.

The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

Energy density and numbers of treatment affect response of keloidal and hypertrophic sternotomy scars to the 585-nm flashlamp-pumped pulsed-dye laser.

BACKGROUND: The 585-nm flashlamp-pumped pulsed-dye laser (PDL) has proven to be the treatment of choice for certain keloids and hypertrophic scars, but the precise fluence, numbers of treatment, and treatment interval remain anecdotal. OBJECTIVE: This study was performed to determine whether the therapeutic outcome of the PDL varies with the energy density (fluence) of the laser pulses and numbers of treatment. METHOD: Ten previously untreated, erythematous, keloidal or hypertrophic median sternotomy scars of 10 patients were divided into 4 segments and were randomly treated with a 585-nm PDL at a fluence of 3, 5, and 7 J/cm(2) to 3 of 4 segments every 4 weeks for a total of 6 treatment sessions. One segment of each patient's scars was untreated and served as a control. Clinical improvement including scar height, erythema, and pliability was evaluated before treatment and every 8 weeks for a total period of 32 weeks. Self-assessment was also determined by patients on a 25% increment of improvement scale comparing week 0 and week 32. RESULTS: A significant improvement in scar height, erythema, and pliability was noted in all laser-treated scar areas. There was no significant difference in treatment outcome versus the fluence of the laser (3, 5, and 7 J/cm(2)), although there was a trend for lower fluences to show more improvement. Objective clinical improvement was seen as early as week 16, after more than two treatments were given. Multiple treatments (>2) appeared to provide a greater percentage of scar resolution. CONCLUSIONS: The clinical improvement of scars after PDL treatment demonstrates no statistically significant fluence dependence in this study, but a trend toward better response with lower fluences is seen. In addition, multiple treatment sessions are suggested for achieving greater response.

Laser resurfacing with a long pulse erbium:YAG laser compared to the 950 ms pulsed CO(2) laser.

BACKGROUND AND OBJECTIVE: Laser resurfacing with the 950 micros pulsed CO(2) laser is an effective treatment for photodamage and acne scarring; however, the potential for prolonged erythema and delayed re-epithelialization dissuade many patients from the procedure. With the use of erbium lasers alone, there is a decrease in the incidence and severity of these adverse sequelae; however, it is difficult to achieve the same degree of improvement as with the CO(2) laser because of the more superficial depth of resurfacing. Thus, new erbium lasers have been developed with longer pulse durations to deliver increased thermal effects to tissue. It is hypothesized that with the use of these lasers, diminished erythema and faster wound healing will be observed as well as enhanced clinical outcomes. STUDY DESIGN/MATERIALS AND METHODS: Sixteen patients were randomized to receive laser resurfacing on one-half of the face with the 950 micros pulsed CO(2) laser (UPCO(2)) followed by short pulse erbium:YAG ablation, and to the other half with a variable pulsed erbium laser (VP Er:YAG) followed by traditional short pulse erbium laser. Patients were evaluated clinically before resurfacing and at 1, 2, 4, 8, and 12 weeks post-operatively. Histologic samples taken at various time periods before and after resurfacing were also evaluated. RESULTS: Overall clinical improvement was equal for both UPCO(2) and VP Er:YAG treated sides with an average improvement in photoaging scores of 57%. Decreased erythema, less edema, and faster healing were observed on the VP Er:YAG treated side. CONCLUSION: The VP Er:YAG laser can achieve a similar degree of improvement as seen with short pulse CO(2) laser resurfacing with decreased thermal tissue effects and decreased risk for adverse sequelae.

Resurfacing of photodamaged skin on the neck with an UltraPulse((R)) carbon dioxide laser.

BACKGROUND AND OBJECTIVE: Successful treatment of facial wrinkles with carbon dioxide or erbium laser resurfacing brings about a more youthful appearance of the skin on the face. A variable degree of contrast with the untreated skin on the neck prompts many patients to request treatment for photodamaged skin on the neck. The objective is to investigate the feasibility of resurfacing photodamaged skin on the neck with the UltraPulse((R)) carbon dioxide laser. SUDY DESIGN/MATERIALS AND METHODS: The study was carried out in two phases. During the first phase, a small area on the upper neck was tested with three different parameters. The best parameter was then used to treat the neck area in a single pass in 10 cases in the second phase. Patients were then evaluated at 3-6 months. RESULTS: The three parameters tested were 200 mJ at CPG settings of pattern 3, size 9, density 6, 300 mJ at CPG 3-9-5, and 300 mJ at CPG 3-9-6. The latter seemed to achieve the best results, and there were no complications at any test sites. This setting was used to treat the whole anterior and anterolateral part of the neck with a single pass, wiping away the resultant epidermal debris. Moderate improvement in color and texture, but no improvement in wrinkling, were observed at 3-6 months. However, a mild degree of patchy hypopigmented scarring in the lower neck was encountered in three cases, as well as one other case of patchy hypopigmentation without textural changes. CONCLUSIONS: Despite some obvious improvements, the risk of scarring and hypopigmentation with the tested parameters out-weighs the potential benefits. The lower part of the neck responded very differently from the upper part. Alternative strategies to achieve better results are discussed.

A double-blind, side-by-side comparison study of low fluence long pulse dye laser to coolant treatment for wrinkling of the cheeks.

BACKGROUND: Nonablative laser resurfacing with various lasers and light sources can improve skin texture and fine lines. The 595 nm pulsed dye laser has been reported to improve rhytides through nonablative mechanisms, minimizing the side effects and recovery period associated with traditional ablative resurfacing techniques. OBJECTIVE: The purpose of this study was to investigate the efficacy of the long pulse flashlamp pumped pulsed dye laser (LPDL) in improving rhytides and stimulating collagen synthesis and dermal remodeling. METHODS: The cheeks of 15 women with moderate to severe photoaging were treated on one side with a series of four monthly LPDL treatments, while the contralateral cheek was treated with cryogen coolant only. Clinical grading was performed at monthly intervals for up to 3 months after the fourth LPDL treatment. Skin biopsy before treatment and at 4-6 weeks was also performed for histologic evaluation and staining for type I procollagen. RESULTS: Eleven of 15 patients demonstrated improvement of the laser-treated cheek while only three of 15 patients the demonstrated improvement on the cryogen-treated cheek. A statistically significant (p = 0.0035) improvement in clinical grading of photodamage was noted in the treated side versus the control. In those patients who improved with LPDL treatment, an improvement of 18.1% in the mean pre- and post-treatment clinical grading scores was observed. Histologic evaluation demonstrated an increase in activated fibroblasts with positive procollagen staining on the LPDL-treated cheek. CONCLUSION: The 595 nm LPDL may be used in the treatment of moderate to severe wrinkles. A mild improvement may be expected with minimal to no side effects.

Collagen tightening induced by carbon dioxide laser versus erbium: YAG laser.

BACKGROUND AND OBJECTIVE: Pulsed CO2 laser resurfacing improves photodamage and acne scarring by ablation of abnormal tissue with subsequent regeneration and remodeling of collagen and through heat induced collagen contraction. Whether collagen contraction persists long-term and helps maintain the skin tightening observed after resurfacing is debated. One possible mechanism of long-term clinical tightening is that of wound contracture that occurs as part of normal wound healing. If normal wound contracture, and not heat induced collagen contraction, is responsible for maintaining the initial skin tightening seen in CO2 laser resurfacing, then equal results would be expected from resurfacing with either CO2 or erbium lasers. The study was performed to determine whether there is a difference in skin tightening secondary to thermally mediated collagen contraction versus that which occurs secondary to tissue contraction of wound healing. The persistence of these changes over 6 months and the histologic characteristics were studied as well. STUDY DESIGN/MATERIALS AND METHODS: Nine patients had four tattoo dots applied to the upper eyelids, with horizontal axis measuring 18-20 mm and the vertical axis 6-10 mm. One month later, one eyelid was treated with three passes of the UltraPulse CO2 laser and the other eyelid with an erbium laser to the end point of early pinpoint bleeding. Three patients were treated with additional passes after pinpoint bleeding was encountered. The total number of pulses used per patient was recorded. Measurements of the vertical and horizontal distances were made after each pass and monthly for 6 months. The treated skin was then excised in performance of an upper lid blepharoplasty and the tissue submitted for histologic analysis. RESULTS: In the vertical plane, the UltraPulse CO2 laser induced an average of 43% tightening intraoperatively and this gradually diminished to an average of 34% by 6 months, whereas the wound contracture of erbium resurfacing was not seen until 1 month postoperatively, at which time 42% tightening was seen, gradually diminishing to 36% at 6 months. Three patients with erbium resurfacing had scarring present. These were the three patients treated most aggressively and also the three patients with the most significant wound contracture. Scarring was not seen on the CO2 treated side in any patients. In the horizontal plane, the CO2 laser caused 31% intraoperative tightening, decreasing to 19% at 6 months. In this plane, the erbium laser induced wound contracture was 12% at 1 month which remained stable and unchanged. CONCLUSIONS: Although wound contraction secondary to tissue healing may result in nearly the same tissue tightening as heat-induced collagen contraction, the two processes are very different and variable, with increased risk of scarring seen with wound contracture, compared with heat-induced collagen tightening. The tissue tightening seen with thermally induced collagen contraction is long-lasting, if not "permanent."

Successful treatment of treatment-resistant laser-induced pigment darkening of a cosmetic tattoo.

BACKGROUND AND OBJECTIVE: Cosmetic tattoo removal has a reported risk of immediate pigment darkening when treated with a high energy, nanosecond pulsed-laser system. Surgical treatment options for this reaction are limited and carry significant risk of scarring and permanent pigment alterations. This report describes the response of a resistant Q-switched ruby laser-induced cosmetic tattoo ink darkening to multiple treatments with the Q-switched alexandrite laser and Q-switch Nd:YAG laser and textural improvement with the UltraPulse CO(2) laser. STUDY DESIGN/MATERIALS AND METHODS: A woman with Q-switched ruby laser-induced pigment darkening of a cosmetic tattoo of the upper lip resistant to four further treatments with the ruby laser and two chemical peels received a total of 26 treatments with the Q-switched alexandrite and Nd:YAG lasers and a single treatment with the UltraPulse CO(2) laser, most treatments being done at monthly intervals. RESULTS: Treatment of the affected areas with the Q-switched alexandrite and Nd:YAG lasers resulted in complete clearing of the pigment without scarring, but revealed some preexisting textural changes. Use of the UltraPulse CO(2) laser smoothed the surface irregularities. CONCLUSION: The Q-switched pigment lasers are a useful modality for treating this pigment darkening reaction. As in this case, multiple treatment sessions with the laser may be necessary but the pigment can be expected to clear eventually without scarring. Any textural changes may be blended with the UltraPulse CO(2) laser with further improvement.

Laser treatment of imipramine-induced hyperpigmentation.

BACKGROUND: Blue or slate-gray hyperpigmentation is seen with a variety of medications, including imipramine. We describe a patient with significant imipramine-induced pigmentation. OBJECTIVE: The purpose of this study was to describe an effective laser treatment resulting in improvement of imipramine-induced hyperpigmentation, without discontinuing the medication. METHODS: The patient underwent treatment with carbon dioxide, erbium, alexandrite, and ruby lasers to hyperpigmented areas. Tissue biopsy specimens taken before treatment, immediately after treatment with the alexandrite laser, and at clearing were analyzed by light microscopy. RESULTS: The Q-switched alexandrite and ruby lasers resulted in clinical improvement in the patient's hyperpigmentation and a decrease in pigment granules on light microscopy. CONCLUSION: Both the Q-switched alexandrite and ruby lasers are effective treatments for imipramine-induced hyperpigmentation. The improvement is progressive with successive sessions.

Laser hair transplantation II.

BACKGROUND: Micrografting has revolutionized hair transplantation, resulting in far more natural results than have been achieved prior to this technique. Operative problems including bleeding, graft compression, and ease of graft insertion have been alleged to be decreased with the use of a high-energy pulsed CO2 laser for creation of recipient sites. However, because of thermal injury to surrounding tissue, diminished hair growth and slower wound healing also have been seen. OBJECTIVE: A new laser handpiece, designed to minimize tissue thermal damage to hair recipient sites was tested in comparison to 18-gauge needle recipient sites in the same patients. Hair growth counts at 6 months as well as various measurements of operative problems were compared. METHODS: Two hundred laser grafts were performed on one scalp side and compared to 200 needle grafts on the opposite side. Hair counts preoperatively and at 6 months were performed. Biopsies for depth and surrounding tissue damage were taken intraoperatively. Time for completion of various stages of the procedure for each side were recorded, as well as the incidence of side effects per side. RESULTS: Hair growth was equal for each side. Bleeding and operative time were significantly reduced and ease of graft insertion was increased on the laser side. Graft compression and scarring were not seen. CONCLUSIONS: Laser hair transplantation is faster than using conventional techniques and results in equal hair growth, and should be considered as a viable alternative technique.

Laser skin resurfacing of the face with a combined CO2/Er:YAG laser.

BACKGROUND: A combined, dual-wavelength CO2/Er:YAG laser system having the ability to deliver both clean ablation of skin with the erbium wavelength and a simultaneous deeper penetrating subablative thermal pulse of CO2 was developed for full-face resurfacing. The CO2 component can be pulsed from 1 to 100 msec at a power of 1-10 W with the Er:YAG component pulsed at 350 microsec at 1.7 J/cm2 through either a computer pattern generator with 3 mm diameter spot size or through a noncollimated spot ranging from 0.2 to 8 mm in diameter. Our previous study using this laser on the neck using a 4-8 mm diameter spot with Er:YAG fluence at 1.7 J and the CO2 at 5 W with a 50 msec pulse at a frequency of 10 Hz showed a higher degree of overall patient satisfaction, as well as improvement in skin texture and skin color, compared to patients treated with an Er:YAG laser alone. OBJECTIVE: This study evaluated the CO2/Er:YAG laser treatment modality in facial resurfacing. METHODS: Ten patients were treated with four passes at 1.7 J with a 4 mm diameter spot and the CO2 at 5 W with a 50-msec pulse at a frequency of 10 Hz. Photoaging scores as well as thermal damage and new collagen formation were compared immediately before and after treatment as well as at 2 weeks and 3 months postoperatively. RESULTS: The average pretreatment periorbital score was 6.2 The average posttreatment periorbital scores were 4.2 (P =.0239) at 2 weeks postoperatively (32% improvement) and 3.8 (P =.0028) at 3 months postoperatively (38% improvement). The average pretreatment perioral score was 5.9. The average posttreatment perioral scores were 3.0 (P =.0001) at 2 weeks postoperatively (49% improvement) and 3.3 (P =.0009) at 3 months postoperatively (44% improvement). The average pretreatment cheek score was 4.7. The average posttreatment cheek scores were 2.7 (P =.0066) at 2 weeks postoperatively (43% improvement) and 3.8 (P =. 0152) at 3 months postoperatively (36% improvement). The average pretreatment forehead score was 4.7. The average posttreatment forehead scores were 3.8 (P =.0340) at 2 weeks postoperatively (33% improvement) and 3.6 (P =.0147) at 3 months postoperatively (37% improvement). The average depth of collagen measured in the dermis pretreatment was 29 microm. The average depth of collagen 3 months posttreatment was 54 microm. This is an average increase of 25 microm or an 86% increase in collagen (P =.006). The average thermal damage immediately after treatment was 20 microm. CONCLUSION: The CO2/Er:YAG laser utilized with four passes at the above-mentioned parameters results in a similar degree of improvement as other forms of laser resurfacing with high-energy, short-pulsed CO2 lasers.

Treatment of facial skin using combinations of CO2, Q-switched alexandrite, flashlamp-pumped pulsed dye, and Er:YAG lasers in the same treatment session.

BACKGROUND: Many patients who seek facial CO2 laser resurfacing for improvement of photodamage are also concerned with "dark circles" under their eyes (periorbital hyperpigmentation) and/or telangiectasia as well as various types of deep scars on their faces. CO2 laser resurfacing alone provides limited improvement for these problems. OBJECTIVE: The purpose of this study was to demonstrate the conjunctive therapeutic effects of the CO2, Q-switched alexandrite, Er:YAG, and/or flashlamp-pumped pulsed dye lasers on facial skin treatments. METHOD: Thirty patients who underwent CO2 laser resurfacing were treated with additional lasers specific for their cosmetic concerns. Twenty patients with facial telangiectasias were treated with the pulsed dye laser immediately prior to CO2 laser resurfacing. Eleven patients with periorbital hyperpigmentation were treated with the Q-switched alexandrite laser immediately following use of the pulsed CO2 laser. Eight patients having sharply defined acne scars were treated with the Er:YAG laser following use of the CO2 laser. All patients had peripheral feathering performed with the Er:YAG laser. Nine patients were treated with all four lasers. RESULTS: In addition to significant improvement of the wrinkle scores from the CO2 laser resurfacing, patients had 75-100% clearing of the periorbital hyperpigmentation. All patients with facial telangiectasia showed virtually 100% improvement. All deep wrinkles and sharply defined scars responded with combined CO2/Er:YAG laser better than with CO2 laser resurfacing alone. All feathering was more uniform, with a more subtle transition to nontreated skin. There were no complications that could be attributed to the simultaneous use of multiple lasers. CONCLUSIONS: For patients who present with multiple cosmetic complaints, combined treatment using appropriate lasers offers excellent therapeutic outcome.

Cutaneous laser resurfacing.

UNLABELLED: Cutaneous resurfacing with the new generation of carbon dioxide and erbium lasers has recently come into favor for the treatment of facial rhytides, photodamage, and scarring. The precise control of these resurfacing lasers over the extent of tissue vaporization minimizes thermal damage to the skin while maximizing therapeutic efficacy. Proper use of resurfacing lasers is contingent upon a complete understanding of their clinical, histologic, and ultrastructural effects, as well as an appreciation of the principles of laser safety. An organized approach to the preoperative, intraoperative, and postoperative management of the patient undergoing laser resurfacing will be provided, including a discussion of prevention and treatment of postoperative side effects and complications. (J Am Acad Dermatol 1999;41:365-89.) LEARNING OBJECTIVE: At the conclusion of this learning activity, participants should be familiar with the clinical, histologic, and ultrastructural effects of resurfacing lasers and be able to discuss the preoperative, intraoperative, and postoperative management of patients undergoing laser resurfacing.

Depth of vaporization and the effect of pulse stacking with a high-energy, pulsed carbon dioxide laser.

BACKGROUND: Laser resurfacing of photodamaged skin has become popular, but questions regarding its safety with regard to the risks of scarring have arisen. OBJECTIVE: This study was designed to investigate the depth of vaporization and residual thermal necrosis of single-pulse vaporization and multiple passes versus pulse-stacking and multiple passes. The potential significance of operator technique and laser parameters is considered. METHODS: Skin samples from surgical excisions were treated by means of a Coherent Ultrapulse carbon dioxide laser at 250 mJ per pulse and 500 mJ per pulse with a 3 mm collimated beam and a repetition rate of 10 Hz. A total of 70 treatment areas were performed. Blinded analysis of the histologic effects of single-pulse, double-pulse, and triple-pulse vaporization after 1 through 10 passes was undertaken. RESULTS: A plateau of vaporization was observed after 3 passes at both 250 and 500 mJ whether single-, double-, or triple-pulse vaporization was used. This plateau occurs at approximately 100 to 250 microm from the skin surface. Thermal necrosis is well controlled only with single-pulse vaporization. There is a direct linear increase in the depth of thermal necrosis both with the number of pulses stacked and the number of passes. CONCLUSION: Pulsed carbon dioxide laser resurfacing is a safe and self-limited procedure if a pulse width of less than 1 msec is used with single-pulse vaporization and fluences of 3.5 J/cm2 and 7.0 J/cm2. There appears to be little justification for performing more than 3 or 4 passes. Pulse stacking may significantly increase residual thermal necrosis, thereby increasing the risk of scarring. Operator technique may be significant in avoidance of this occurrence.

Laser resurfacing of the neck with the Erbium: YAG laser.

BACKGROUND: Laser resurfacing of the face is widely used to correct the effects of photoaging. The neck also develops a similar degree of photoaging, but is not usually treated because a higher incidence of adverse effects can occur with laser treatment. OBJECTIVE: To present a new method for treating photoaged skin of the neck with an erbium:yttrium aluminum garnet (Er:YAG) laser. METHODS: Twenty patients underwent Er:YAG laser resurfacing of the neck with one of two methods. Method 1 consisted of using the Er:YAG with a 5-mm diameter collimated beam at a fluence of 8.7 J/cm2 followed by a second pass using a 0.2 mm diameter non-collimated spot at 1.7 J in a defocused mode with spot sizes ranging from about 5 to 10 mm in diameter (fluences from 2-9 J/cm2). Method 2 consisted of treating the entire neck with a single pass of the Er:YAG laser with a 4 mm diameter non-collimated spot at 1.7 J (fluence of 13.5 J/cm2). A second pass at identical settings was made on the upper half of the neck with a more defocused pass using a 6-10 mm diameter spot (fluence of 2-6 J/cm2) on the lower half of the neck. Patients were evaluated by two nontreating physicians as to overall satisfaction and improvement in skin texture and color. RESULTS: Overall, 51% of patients were satisfied with their results. Skin texture improved an average of 39%. Method 1 produced a 28% improvement, Method 2 a 48% improvement. Skin color improved an average of 37%. Method 1 produced a 28% improvement, Method 2 a 45% improvement. CONCLUSION: Photoaged skin of the neck can be effectively treated with the Er:Yag laser with minimal adverse effects.