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Biomedical subjects

T S Alster

Publications and source records attributed to T S Alster.

At least 19 recordsLinked to original sources

Clinical and histologic evaluation of six erbium:YAG lasers for cutaneous resurfacing.

BACKGROUND: Several erbium:YAG lasers are currently available for cutaneous laser resurfacing. Although different laser systems are purported to produce equivalent laser energies to produce similar laser-tissue interactions, no comparative clinical or histologic studies have been performed to objectively demonstrate their relative efficacies. OBJECTIVE: The purpose of the present study was to examine the in vivo clinical and histopathologic effects of six different erbium:YAG resurfacing lasers. METHODS: A blinded, prospective study using six different erbium lasers (Candela, Continuum Biomedical, HGM, MDLT, SEO, Sharplan/ESC) was performed. The facial halves of 12 patients were randomly resurfaced with one of the six laser systems by using an identical laser technique at 5.0 J/cm2. Intraoperative skin biopsies were obtained after each of three laser passes in two patients for blinded histologic determination of tissue ablation level and presence of residual thermal damage. Clinical assessments of reepithelialization rates, severity and duration of erythema, side effects, and degree of clinical improvement were made at 0.5, 1, 2, 4, 12, 26, and 52 weeks postoperatively. RESULTS: Irrespective of the erbium laser system used, complete reepithelialization typically occurred at 0.5 weeks and resolution of erythema was noted within 1-2 weeks postoperatively. A mean clinical improvement of 50% was observed, with photodamaged skin showing greater improvement than scarred skin. The most common postoperative side effect was hyperpigmentation, with all affected patients having either darker skin tones or preceding dermal inflammation. Three laser passes were needed to effect total epidermal ablation when using any one of the erbium:YAG systems. CONCLUSIONS: Equivalent clinical and histologic results were seen after each of the six erbium:YAG lasers studied. Erbium:YAG laser resurfacing can be used to significantly improve mild cutaneous photodamage and atrophic scars.

Adult

Long-pulsed alexandrite laser-assisted hair removal at 5, 10, and 20 millisecond pulse durations.

BACKGROUND: Several laser systems with varying wavelengths, pulse durations, and energy fluences are currently utilized for hair removal. However, the ideal laser parameters and treatment candidates for photoepilation remain largely unknown. The medical literature lacks a wealth of experimental data to sufficiently document the long-term safety and efficacy of laser-assisted hair removal. This study examines the clinical efficacy and side effect profile of long-pulsed alexandrite laser-assisted hair removal utilizing laser pulse durations of either 5, 10, or 20 milliseconds (ms). STUDY DESIGN/METHODS: Laser-assisted hair removal was performed on 36 subjects with a long-pulsed alexandrite laser. Areas of unwanted hair growth on the face, back, and legs were divided linearly into four 1 cm2 or 2 cm2 quadrants. Experimental regions included a control quadrant and three additional quadrants, which were treated with the alexandrite laser using an average fluence of 18 J/cm2, with a 10 mm spot size at either a 5, 10, or 20 ms pulse duration. Hair counts and photographs were obtained before treatment, immediately following irradiation, 1 week and 1, 3, and 6 months postoperatively. RESULTS: All laser-treated quadrants displayed a significant delay in hair regrowth compared to control nontreated quadrants at postoperative week 1 and months 1 and 3. Hair counts were reduced by 66% at 1 month, 27% at 3 months, and 4% at 6 months. No significant differences in clinical efficacy or side effect profiles were observed between treatment quadrants, yet a trend towards less post-treatment erythema and hyperpigmentation was noted with the 20 ms pulse duration. CONCLUSIONS: Equivalent long-term hair removal for up to 6 months was achieved with the long-pulsed alexandrite laser at 5, 10, and 20 ms pulse durations at an average fluence of 18 J/cm2. Side effects were limited and transient.

Adult

Laser-assisted hair removal: side effects of Q-switched Nd:YAG, long-pulsed ruby, and alexandrite lasers.

BACKGROUND: Laser-assisted hair removal has become popularized using wavelengths in both the red and infrared regions of the electromagnetic spectrum. These photoepilation devices target follicular melanin or an exogenous pigment placed within the follicle resulting in thermal damage to the hair follicle and shaft. However, melanocytes and keratinocytes located within the superficial layers of the skin also absorb red and infrared laser radiation. This may result in unwanted epidermal injury during the hair removal process. OBJECTIVE: The purpose of this study was to examine a large patient population to determine the frequency of side effects using 3 different hair removal laser systems with various wavelengths, pulse durations, and treatment protocols. METHODS: A retrospective chart review and digital photographic analysis of the side effects resulting from 900 consecutive laser-assisted hair removal treatments delivered over a 24-month study period, by means of either a Q-switched Nd:YAG laser with pretreatment wax-epilation and topical carbon solution, a long-pulse ruby laser with a contact cooling tip, or a long-pulse alexandrite laser are reported. RESULTS: Treatment pain, erythema, edema, hypopigmentation and hyperpigmentation, blistering, crusting, erosions, purpura, and folliculitis were observed. The majority of undesirable tissue effects occurred on tanned skin or in Fitzpatrick skin phototypes III and higher. The ruby and alexandrite laser systems resulted in the majority of side effects seen. The effects of seasonal variations, anatomic treatment location, and sun exposure were striking within the ruby and alexandrite laser groups. No infections, scarring, or long-term complications occurred. CONCLUSION: Laser-assisted hair removal is a safe procedure when patient characteristics such as skin type, anatomic location, and sun-exposed or tanned skin are considered during selection of laser treatment parameters. Lasers emitting wavelengths with high melanin absorption capabilities should be used in a conservative manner when treating patients with dark skin phototypes or suntans. No long-term complications, infections, or scarring occurred in this study population.

Adult

Periorbital rejuvenation: a review of dermatologic treatments.

BACKGROUND: The periorbital region serves as a barometer of chronologic and environmental age and, as such, patients often seek its cosmetic rejuvenation. OBJECTIVE: The purpose of this article was to review the dermatologic treatments available for periorbital skin rejuvenation. METHODS: Topical retinoic and glycolic acid preparations, chemical peels, botulinum and collagen injections, dermabrasion, and laser resurfacing procedures for periorbital skin rejuvenation were reviewed. The relative benefits and risks of each treatment were detailed. RESULTS: Minimal photodamage with mild rhytides should be responsible to topical acid therapy and superficial peels, whereas moderate wrinkling and photodamage generally require medium-depth peels, collagen injections, or erbium:YAG laser resurfacing. Deeper rhytides and more extensive cutaneous photo-damage usually necessitate CO2 laser resurfacing and botulinum injections. CONCLUSIONS: Proper patient selection and assessment of aging severity are critical to determine the best therapeutic option.

Botulinum Toxins, Type A

Nodular amyloidosis treated with a pulsed dye laser.

BACKGROUND: Nodular amyloidosis is a rare form of primary localized cutaneous amyloidosis which is characterized by single or multiple nodules located on the extremities, trunk, genitalia, or face. OBJECTIVE: To determine the clinical and histologic response of nodular amyloidosis to pulsed dye laser treatment. METHODS: Biopsy-proven amyloid nodules were treated with a 585-nm pulsed dye laser (average fluence 5.25 J/cm2; 10 mm spot) at 6- to 8-week time intervals. Clinical and histologic examination of laser-irradiated nodules were performed before and 6 weeks after the final laser treatment. RESULTS: Clinical improvement in the color, size, and pliability of nodules was noted and maintained for 6 months. Histologic examination revealed decreased inflammation and improvement in dermal collagen after laser irradiation. CONCLUSIONS: Since amyloid fibrils may be formed in association with dermatan sulfate-an essential matrix component in collagen fiber formation, it is postulated that the improvement seen in amyloid nodules after pulsed dye laser treatment may be attributed to a mechanism similar to that seen with hypertrophic scars.

Amyloidosis

Effect of pretreatment on the incidence of hyperpigmentation following cutaneous CO2 laser resurfacing.

BACKGROUND: Transient hyperpigmentation is the most common complication seen following cutaneous carbon dioxide (CO2) laser resurfacing. OBJECTIVE: The purpose of this study was to determine whether the use of a topical skin lightening regimen prior to cutaneous laser resurfacing reduces the incidence of post-laser resurfacing hyperpigmentation. METHODS: One hundred consecutive CO2 laser resurfacing patients (skin types I-III) were randomized to receive preoperative treatment with 10% glycolic acid cream twice daily (n=25), hydroquinone 4% cream qHS and tretinoin 0.025% cream twice daily (n=25) or no pretreatment (n=50, control) for at least 2 weeks. Clinical and photographic assessments were performed prior to laser resurfacing and at 4 and 12 weeks following treatment. RESULTS: There was no significant difference in the incidence of post-CO2 laser resurfacing hyperpigmentation between subjects who received pretreatment with either topical glycolic acid cream or combination tretinoin/hydroquinone creams and those who received no pretreatment regimen. CONCLUSION: It is postulated that reepithelialization after cutaneous laser resurfacing includes follicular melanocytes that have not been affected by topical pretreatment. When instituted as a component of the skin care regimen postoperatively, topical hydroquinone, tretinoin and/or glycolic acid preparations may be helpful in reducing post-laser resurfacing hyperpigmentation.

Administration, Cutaneous

Comparison of four carbon dioxide resurfacing lasers. A clinical and histopathologic evaluation.

BACKGROUND: Several high-energy, pulsed and scanned carbon dioxide (CO2) lasers are currently available for cutaneous resurfacing. Although each laser system adheres to the same basic principles of selective photothermolysis, there are significant differences between lasers with respect to tissue dwell time, energy output, and laser beam profile. These differences may result in variable clinical and histologic tissue effects. OBJECTIVE: The purpose of this study was to examine the in vivo clinical and histopathologic effects of four different high-energy, pulsed or scanned CO2 resurfacing lasers. METHODS: A prospective study using four different CO2 resurfacing lasers (Coherent UltraPulse, Tissue Technologies TruPulse, Sharplan FeatherTouch, and Luxar NovaPulse) was performed. The cheeks of seven patients were divided into four quadrants. Each quadrant was randomly assigned to receive treatment with one of four CO2 lasers. Skin biopsies were obtained intraoperatively from each quadrant, after each of three laser passes, and at 1 and 3 months postoperatively. Blinded clinical assessments of each laser quadrant were made at 1, 3, and 6 months postoperatively by three physicians. Degree of lesional improvement as well as erythema severity, re-epithelialization rates, and presence of side effects were recorded. Blinded histologic examination of laser-treated quadrants was performed to determine the amount of tissue ablation, residual thermal damage, inflammation, and new collagen synthesis. RESULTS: The four CO2 lasers produced equivalent clinical improvement of rhytides and scars. Re-epithelialization occurred in all laser quadrants by day 7. Postoperative erythema was most intense in the quadrants treated by UltraPulse and NovaPulse; however, overall duration of erythema was equivalent for all four laser systems (3 months). Postinflammatory hyperpigmentation was the most frequently encountered side effect and occurred with equal frequency in each quadrant. No scarring, hypopigmentation, or infections were observed. After one laser pass, histologic examination revealed partial ablation of the epidermis with the TruPulse laser and complete epidermal ablation using the UltraPulse, NovaPulse, and FeatherTouch laser systems. The greatest degree of residual thermal damage was seen after FeatherTouch and NovaPulse laser irradiation. New collagen formation was greatest in the UltraPulse and FeatherTouch laser-irradiated quadrants. CONCLUSIONS: Equivalent clinical results were observed using the FeatherTouch, NovaPulse, TruPulse, and UltraPulse CO2 lasers. While postoperative erythema intensity differed between laser systems, total duration of erythema was equivalent. The four lasers under study resulted in minimal residual thermal damage and stimulated new collagen formation within 6 months after treatment.

Adult

Famciclovir prophylaxis of herpes simplex virus reactivation after laser skin resurfacing.

BACKGROUND: Cutaneous laser resurfacing with carbon dioxide and erbium:YAG lasers has achieved remarkable clinical results with a relatively low risk of morbidity and complications. The incidence of herpes simplex virus (HSV) reactivation after resurfacing can be decreased by prophylaxis with antiviral agents. Famciclovir is effective in the suppression and treatment of HSV infections; however, no studies have examined the optimum dosing regimen for HSV prophylaxis in laser resurfacing. OBJECTIVE: The objective of this study was to determine the efficacy of 2 doses of famciclovir as prophylactic anti-HSV therapy during cutaneous laser resurfacing. METHODS: Ninety-nine consecutive patients undergoing full-face laser or perioral resurfacing received either 500-mg or 250-mg famciclovir twice daily, beginning 24 hours prior to laser resurfacing and continuing for 10 days. RESULTS: No HSV recurrences were seen in 90% of patients receiving famciclovir at either dose. Approximately one-third of patients in each group with a positive history of oral herpes labialis experienced HSV recurrence compared to 5% of those without a known HSV history. CONCLUSIONS: Famciclovir 250-mg or 500-mg twice daily is effective in the prevention of HSV recurrence in patients undergoing cutaneous laser resurfacing. Based on our clinical experience, a 500-mg dose is suggested for patients with a strong history of HSV, while 250-mg should be sufficient for those without prior HSV.

2-Aminopurine

Effect of botulinum toxin type A on movement-associated rhytides following CO2 laser resurfacing.

BACKGROUND: Many patients who undergo CO2 laser resurfacing for correction of rhytides experience recurrence of movement-associated wrinkles within 6 to 12 months following the laser procedure. OBJECTIVE: The purpose of this study was to evaluate the effect of botulinum toxin type A (Botox) injections on movement-associated rhytides following cutaneous laser resurfacing. METHODS: Forty patients who had received full face CO2 laser resurfacing for the treatment of facial rhytides were randomized to receive Botox injections to the glabella, forehead or lateral canthal regions or to receive no additional treatment (control group). Clinical and photographic assessments were performed at baseline and at 3, 6 and 9 months. RESULTS: Enhanced and more prolonged correction of forehead, glabellar and/or lateral canthal rhytides was observed in patients treated with Botox injections postoperatively compared to non-Botox treated control patients. CONCLUSION: The use of botulinum toxin type A following cutaneous CO2 laser resurfacing results in prolonged correction of movement-associated rhytides. It is advised that patients receive information regarding the benefits of maintenance therapy with botulinum toxin as part of their routine preoperative education.

Adult

Cutaneous CO2 laser resurfacing infection rate with and without prophylactic antibiotics.

BACKGROUND: Cutaneous laser resurfacing is a well-accepted modality, with excellent clinical outcomes and low morbidity rates, for the treatment of a variety of epidermal and dermal lesions. The use of antibiotic prophylaxis continues to be an area of controversy, with laser practitioners divided in their approach. OBJECTIVE: To identify the rate of postoperative bacterial infection following full-face carbon dioxide (CO2) laser resurfacing with and without antibiotic prophylaxis. METHODS: A retrospective chart review of 133 consecutive patients following full-face CO2 laser resurfacing was performed. The rate, severity, duration, and subsequent treatment of bacterial infections observed in four treatment categories were recorded: (1) no antibiotic prophylaxis; (2) intraoperative single-dose intravenous cephalexin (1 g); (3) postoperative oral azithromycin (1.5 g over 5 days); (4) intraoperative IV cephalexin (1 g) and postoperative oral azithromycin (1.5 g). RESULTS: A significantly higher rate of infection occurred in patients receiving combination intraoperative and/or postoperative antibiotic prophylaxis. The most frequently cultured organisms included Enterobacter and Pseudomonas species. CONCLUSION: The rate of postoperative bacterial infections after full-face CO2 laser resurfacing in this retrospective study was not significantly reduced with the use of prophylactic antibiotics.

Adult

Prolonged clinical and histologic effects from CO2 laser resurfacing of atrophic acne scars.

BACKGROUND: The recent development of high-energy pulsed CO2 lasers that minimize thermal injury to uninvolved adjacent structures has revolutionized the manner in which atrophic facial scars are recontoured. Significant improvement of atrophic scars with laser resurfacing has clearly been demonstrated; however, the exact timing for assessment of skin for further treatment has varied due to the unknown amount of time needed after laser scar resurfacing to effect maximal collagen formation and remodeling. OBJECTIVE: The aim of this study was to determine the immediate and long-term (12-18 months) histologic and clinical effects of atrophic acne scars after CO2 laser resurfacing in order to provide physician guidelines for postoperative clinical assessment for retreatment. METHODS: Sixty patients (50 women, 10 men, mean age 38 years, skin types I-V) with moderate to severe atrophic facial scars were evaluated. Nineteen patients received regional cheek treatment and 41 patients received full-face resurfacing with a high-energy pulsed CO2 laser. Independent clinical assessments of treated scars were performed at 1, 6, 12, and 18 months and blinded histologic analyses were made of skin biopsies immediately prior to and after laser resurfacing, and at 1, 6, 12, and 18 months postoperatively in six patients. RESULTS: Significant immediate and prolonged clinical improvement in skin tone, texture, and appearance of CO2 laser-irradiated scars was seen in all patients. Average clinical improvement scores were 2.22 (69%) at 1 month, 2.1 (67%) at 6 months, 2.37 (73%) at 12 months, and 2.5 (75%) at 18 months. Continued collagenesis and subsequent dermal remodeling were observed on histologic examination of biopsied tissue up to 18 months after surgery. CONCLUSION: Continued clinical improvement was observed as long as 18 months after CO2 laser resurfacing of atrophic scars, with an 11% increase in improvement observed between 6 and 18 months postoperatively. We propose that a longer postoperative interval (12-18 months) prior to assessment for re-treatment be advocated in order to permit optimal tissue recovery and an opportunity for collagen remodeling.

Acne Vulgaris

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.

Carbon Dioxide

Successful treatment of porokeratosis with 585 nm pulsed dye laser irradiation.

Porokeratosis, a keratinization and fibroblast cutaneous disorder, is a progressive disease with limited treatment options. We describe a case of linear porokeratosis that responded favorably to a series of 585 nm pulsed dye laser treatments. In addition to its vascular specificity, the pulsed dye laser presumably produces a direct effect on collagen, as well as an indirect effect on histamine and mast cells that could account for the clinical changes seen in our patient.

Female

Preoperative and postoperative considerations for carbon dioxide laser resurfacing.

Cutaneous laser resurfacing is a tremendous advance in the treatment of photoaged skin. With the recent developments in laser technology, the procedure has become widely utilized among many physician subspecialists. The latest laser systems permit controlled vaporization of skin so that most novice operators feel comfortable with the technique in a short period of time. Nevertheless, there are many issues that need to be addressed before performing the procedure. First, not every person is an appropriate candidate for laser resurfacing. Second, both the physician and the patient must be aware of the preoperative preparation and prolonged postoperative care involved with the procedure. Finally, the physician must be able to identify and treat, and the patient must be educated about, the side effects and potential complications associated with the procedure. It is only by addressing these issues that the clinical results obtained by CO2 laser resurfacing can be maximized.

Female

Pulsed dye laser treatment of hypertrophic burn scars.

Hypertrophic burn scars are notoriously difficult to treat because of their extensive tissue involvement and tendency to worsen with hypertrophy and contracture formation. Various therapies have been advocated in the past, including surgical excision and grafting, dermabrasion, and corticosteroids, with distinct cosmetic limitations. The 585-nm pulsed dye laser has been shown previously to be effective in the treatment of a variety of traumatic and surgical scars with improvement in scar texture, color, and pliability with minimal side effects. Sixteen patients with 40 hypertrophic burn scars resulting from chemical peels, carbon dioxide laser procedures, and accidental thermal injury were treated with a 585-nm pulsed dye laser. Sequential photographic and clinical assessments were recorded in all patients. Histologic evaluations of skin punch biopsies before and after laser irradiation were performed when possible. Symptomatic improvement of scars was reported after one treatment. Decreased scar erythema with improved texture and pliability was observed after an average of 2.5 treatments. No correlation was found between scar duration, location, or etiology and response to treatment. Normal number of dermal fibroblasts with decreased sclerosis was observed on histologic examination of laser-irradiated scars. The 585-nm pulsed dye laser irradiation of hypertrophic burn scars can effectively improve scar pliability and texture and decrease erythema and associated symptoms yielding cosmetically and functionally acceptable clinical results.

Adult

Review of cutaneous lasers and their applications.

BACKGROUND: The use of lasers has assumed an increasingly important role in the treatment of a variety of cutaneous lesions over the past few decades. Because of their effectiveness, physicians from a variety of specialties have incorporated lasers into their practices. Unfortunately, widespread availability of lasers and the public's fascination with their potential uses have created extraordinary, often unrealistic, expectations. METHODS: We review the laser systems most frequently used to treat skin conditions. RESULTS: We discuss lasers with specificity for vascular malformations and pigmentary disorders as well as for tattoos and scars. Also, we review the latest techniques for cutaneous laser resurfacing with carbon dioxide and erbium:YAG lasers. Last, we briefly outline future uses of lasers and ongoing investigations, including laser treatment of leg veins and laser-assisted hair removal. CONCLUSIONS: Lasers, when properly used, offer clear advantages when compared with older, traditional approaches. Laser technology is clearly at its best when the characteristics of selectivity and specificity apply. Significant improvement and even elimination of many cutaneous lesions can now be accomplished with reduced risks to the patient when proper patient selection and laser treatment parameters are chosen.

Cicatrix

Laser scar revision: comparison of CO2 laser vaporization with and without simultaneous pulsed dye laser treatment.

BACKGROUND: Over the past decade, the 585-nm pulsed dye laser (PDL) has been used successfully to treat a variety of cutaneous vascular lesions as well as hypertrophic scars. Laser scar revision has been revolutionized by the recent development of high-energy, pulsed carbon dioxide (CO2) laser systems. These new CO2 lasers allow controlled vaporization of thin layers of skin while minimizing damage to surrounding dermal structures. OBJECTIVE: To determine the effect of a high-energy, pulsed CO2 laser alone and in combination with a 585-nm PDL on nonerythematous hypertrophic scars. METHODS: Twenty patients with nonerythematous hypertrophic scars were treated with a high-energy, pulsed CO2 laser. One-half of each scar was additionally treated with the 585-nm PDL laser. Sequential clinical and photographic analyses were performed independently by two blinded assessors. In addition, erythema reflectance spectrometry measurements were obtained from the scars before and at regular postoperative intervals. RESULTS: Global assessment scores and erythema spectrometry measurements were significantly improved after laser treatment. Combination CO2 and PDL laser treatment resulted in more significant improvement than CO2 laser irradiation alone. CONCLUSION: Concomitant use of the high-energy, pulsed CO2 and PDL laser systems was superior to CO2 laser vaporization alone for revision of nonerythematous hypertrophic scars. Once again, the vascular specificity of the 585-nm PDL has been linked to improvement in hypertrophic scar tissue.

Adolescent