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R Rox Anderson

Publications and source records attributed to R Rox Anderson.

At least 19 recordsLinked to original sources
PubMed2007

Effects of 532 nm pulsed-KTP laser parameters on vessel ablation in the avian chorioallantoic membrane: implications for vocal fold mucosa.

OBJECTIVES: Selective vascular ablation (photoangiolysis) using pulsed lasers that target hemoglobin is an effective treatment strategy for many vocal fold lesions. However, vessel rupture with extravasation of blood reduces selectivity for vessels, which is frequently observed with the 0.45-ms, 585-nm pulsed dye laser. Previous studies have shown that vessel rupture is the result of vaporization of blood, an event that varies with laser pulse width and pulse fluence (energy per unit area). Clinical observations using a 532-nm wavelength pulsed potassium-titanyl-phosphate (KTP) laser revealed less laser-induced hemorrhage than the pulsed dye laser. This study investigated settings for the pulsed KTP laser to achieve selective vessel destruction without rupture using the avian chorioallantoic membrane under conditions similar to flexible laryngoscopic delivery of the laser in clinical practice. STUDY DESIGN: The chick chorioallantoic membrane offers convenient access to many small blood vessels similar in size to those targeted in human vocal fold. Using a 532-nm pulsed KTP laser, pulse width, pulse energy, and working distance from the optical delivery fiber were varied to assess influence on the ability to achieve vessel coagulation without vessel wall rupture. METHODS: Third-order vessels (n = 135) were irradiated: Energy (471-550 mJ), pulse width (10, 15, 30 ms), and fiber-to-tissue distance (1 mm, 3 mm) were varied systematically. RESULTS: Selective vessel destruction without vessel wall rupture was more often achieved by increasing pulse width, increasing the fiber-to-tissue distance, and decreasing energy. Vessel destruction without rupture was consistently achieved using 15- or 30-ms pulses with a fiber-to-tissue distance of 3 mm (pulse fluence of 13-16 J/cm). CONCLUSIONS: This study substantiates our clinical observation that a 532-nm pulsed KTP laser was effective for ablating microcirculation while minimizing vessel wall rupture and hemorrhage.

Animals↗
PubMed2006

Virtual biopsy of the joint tissues using near-infrared, reflectance confocal microscopy. A pilot study.

Standard noninvasive imaging techniques applied to joints provide gross morphological features, insufficient for assessing histological detail. On the other hand, biopsying is invasive, time consuming, and may involve unwanted processing artifacts. Near-infrared reflectance confocal microscopy is a technique that allows serial, high-resolution optical sectioning through intact tissues without employing exogenous fluorescent stains. The aim of this work was to evaluate the potential utility of near-infrared reflectance confocal microscopy for providing immediate histological information on meniscus, articular cartilage, epiphyseal plate, bone, muscle, and tendon. Images from near-infrared reflectance confocal microscopy were compared with mirror routine histology sections. Characteristic architectural features were readily visualized in the three dimensions of space. Additionally, the use of experimental contrast agents highlighted the localization of nuclei. Limitations include penetration depth and minor optical artifacts. In conclusion, near-infrared reflectance confocal microscopy is a useful technique for immediate, nondestructive, serial "virtual" sectioning through intact tissues, being thus a potential adjunct to current imaging techniques in orthopedics.

Animals↗
PubMed2006

Q-switched ruby versus long-pulsed dye laser delivered with compression for treatment of facial lentigines in Asians.

BACKGROUND AND OBJECTIVES: Q-switched lasers have been used for the treatment of lentigines but post-inflammatory hyperpigmentation (PIH) can be an issue especially in Asians. The 595 nm long-pulsed dye laser (LPDL) has been used for the treatment of vascular lesions and although it is well absorbed by oxyhemoglobin, it is also absorbed by melanin. To use this device for the treatment of facial lentigines, we attached a flat glass lens to the tip of the laser's handpiece, allowing compression of the skin during treatment. In doing so, eliminated the absorption by oxyhemoglobin. This prospective study aims to compare the efficacy and complications of such an approach to the use of Q-switched ruby laser (QSRL) in the treatment of facial lentigines in Asians. STUDY DESIGN/MATERIALS AND METHODS: Eighteen Asian patients (1 male, 17 female) with facial lentigines Fitzpatrick skin types III-IV were enrolled. One of the lentigines present was treated with LPDL by compression method and the other one was treated with QSRL. A LPDL emitting wavelength of 595 nm, spot size of 7 mm was used, with fluence between 10 and 13 J/cm(2) and pulse duration of 1.5 milliseconds. Cryogen spray cooling was not used. A 694 nm QSRL was used with a spot size of 4 mm, fluence of 6-7 J/cm(2), and pulse duration of 30 nanoseconds. Lightening of the lesions was assessed by reflectance spectrometer Erythema, hypo- or hyperpigmentation and scarring were also assessed by clinical examinators. RESULTS: The degree of clearing achieved with the two lasers was 70.3% and 83.3% for QSRL and LPDL, respectively. All QSRL treated areas developed erythema whereas only 4 of 18 LPDL treated areas developed erythema. Hyperpigmentation was seen in four patients after QSRL, but not after LPDL. There was no scarring or hypopigmentation. CONCLUSIONS: LPDL delivered with a compression method is more effective than QSRL for facial lentigines. Complications after LPDL treatment were substantially less frequent than after QSRL. The addition of compression technique may allow "vascular" pulsed dye laser to be used for treating a variety of pigmented lesions.

Adult↗
PubMed2006

Skin responses to fractional photothermolysis.

BACKGROUND AND OBJECTIVE: Fractional photothermolysis (FP) is a new concept using arrays of microscopic thermal damage patterns to stimulate a therapeutic response. We analyzed epidermal and dermal response to FP with the aim of correlating histological and clinical response. STUDY DESIGN/MATERIALS AND METHODS: Twelve subjects received a single treatment with a prototype diode laser emitting at a wavelength of 1,500 nm, delivering 5 mJ per microscopic treatment zone (MTZ), and a density of 1,600 MTZs/cm(2) on the forearm. Biopsies were procured over a period of 3 months. The biopsies were analyzed by two blinded dermatopathologists using hematoxylin and eosin (Hematoxylin and Eosin Stain), Elastica von Gieson, nitro-blue-tetrazolium-chloride (NBTC) viability, and immunohistochemistry stains. Furthermore, the treatment sites were evaluated in vivo by confocal microscopy. RESULTS AND DISCUSSION: Twenty-four hours after fractional photothermolysis, the continuity of the epidermal basal cell layer is restored. Complete epidermal regeneration is obtained 7 days after the treatment. Microscopic epidermal necrotic debris (MENDs) are seen as early as 1 day after FP. MENDs contain melanin pigment, and are shed from the epidermis within 7 days. Evidence of increased collagen III production is shown with immunohistochemistry (IHC) staining 7 days after FP. IHC for heat shock protein 70 (HSP 70) shows the expression of HSP 1 day after FP, and IHC for alpha smooth muscle actin shows the presence of myofibroblasts 7 days after FP. These findings are concordant with the induction of a wound healing response by FP. There is no evidence of residual dermal fibrosis 3 months after treatment. CONCLUSION: A single treatment with fractional photothermolysis induces a wound healing response in the dermis. A mechanism for the precise removal of epidermal melanin is described, in which MENDs act as a melanin shuttle.

Actins↗
PubMed2006

Complications of laser dermatologic surgery.

BACKGROUND AND OBJECTIVE: Innovations in lasers, light and radiofrequency devices have allowed for improved therapeutic efficacy and safety and the ability to treat patients with an ever-increasing number of medical and aesthetic indications. Safety remains a primary concern and the timely communication of complications and their management is vital to insure that treatments be as safe as possible. The purpose of this report on the Proceedings of the First International Laser Surgery Morbidity Meeting is to provide laser experts the opportunity to present and discuss complications that their patients have experienced and how they were successfully managed. METHODS: Laser experts were invited to present complications of laser, light, and radiofrequency treatments that their patients have experienced and to discuss the potential mechanisms leading to the complications their management and final outcomes. RESULTS: Nineteen unique cases are presented and the clinical management of each case discussed. Eighteen sets of pre- and post-operative photos are presented. CONCLUSION: This report shows that even experts, with extensive experience using light-based therapies, can and do have patients who develop complications. Sound clinical judgment, and knowing how to avoid complications and their timely post-operative management, is essential to insure optimal therapeutic outcome.

Cicatrix↗
PubMed2006

Selective photothermolysis of lipid-rich tissues: a free electron laser study.

BACKGROUND AND OBJECTIVES: In theory, infrared vibrational bands could be used for selective photothermolysis of lipid-rich tissues such as fat, sebaceous glands, or atherosclerotic plaques. STUDY DESIGN/MATERIALS AND METHODS: Absorption spectra of human fat were measured, identifying promising bands near 1,210 and 1,720 nm. Photothermal excitation of porcine fat and dermis were measured with a 3.5-5 microm thermal camera during exposure to the free electron laser (FEL) at Jefferson National Laboratory. Thermal damage to full-thickness samples exposed at approximately 1,210 nm through a cold contact window, was assessed by nitrobluetetrazolium chloride staining in situ and by light microscopy. RESULTS: Photothermal excitation of fat was twice that of dermis, at lipid absorption bands (1,210, 1,720 nm). At 1,210 nm, a subcutaneous fat layer several mm thick was damaged by FEL exposure, without apparent injury to overlying skin. CONCLUSION: Selective photothermal targeting of fatty tissues is feasible using infrared lipid absorption bands. Potential clinical applications are suggested by this FEL study.

Adipose Tissue↗
PubMed2006

Novel virtual biopsy of the kidney with near infrared, reflectance confocal microscopy: a pilot study in vivo and ex vivo.

PURPOSE: Current diagnostic strategies for the kidney combine noninvasive imaging techniques with invasive procedures such as needle biopsy. However, renal needle biopsy is not devoid of risks, such as bleeding or infection. Additionally, histology studies are limited to ex vivo morphology and processing induces tissue artifacts, is time-consuming and limits the performance of further studies. Near infrared, reflectance CM is a novel technique that allows high resolution optical sectioning through intact tissues without using any exogenous fluorescent stains. Contrast between structures is based on the natural differences in refractivity. In this pilot study we assessed the usefulness of CM in the study of the kidney in vivo and ex vivo. MATERIALS AND METHODS: Kidneys of live rats were imaged with CM. Contrast in images is based on native properties of the tissue upon being shone with a near infrared laser. By convention hyperrefractile structures are seen as white and hyporefractile structures are seen as black. CM imaging planes varied along the x, y and z axes of space. Images of live kidney were compared with those from ex vivo CM imaging and standard histology procedures. RESULTS: The tubules, glomeruli, vessels and interstitium were readily identified, revealing intracellular detail. Differences between the kidney in vivo and ex vivo were also observed. Experimental contrast agents further highlighted the nuclei. CONCLUSIONS: CM is a useful noninvasive imaging technique that is an adjunct to current techniques for 3-dimensional study of the kidney in vivo and ex vivo. Future technical developments will provide key applications during surgical intervention, transplantation and rapid tissue assessment.

Animals↗
PubMed2006

Imaging the human vocal folds in vivo with optical coherence tomography: a preliminary experience.

OBJECTIVES: Optical coherence tomography (OCT) and polarization-sensitive OCT (PS-OCT) are promising noninvasive methods for in vivo, cross-sectional imaging of the microstructure of the vocal folds. Previous studies in other tissues have shown an axial resolution of less than 10 microm and a maximum imaging depth of about 2 mm. The objectives of this pilot study were to obtain images from the vocal folds of subjects who were being evaluated and/or treated for vocal fold disease and to evaluate how well normal and pathologic microstructure could be seen in these images. METHODS: Twenty-six vocal folds in 13 subjects were imaged with a flexible OCT probe. The images were successfully collected from subjects who were either topically anesthetized or under general anesthesia for microlaryngoscopic procedures. RESULTS: The thickness of the epithelium, the relative collagen content of the subepithelial connective tissue, and certain characteristic features of lesions (including cysts, scarring, and papilloma) were seen in the OCT and PS-OCT images. CONCLUSIONS: "Live microscopy" of the human vocal folds is very promising for improved diagnosis, mapping, and treatment planning. To our knowledge, this study is the first application of PS-OCT for in vivo imaging of the human vocal folds.

Humans↗
PubMed2006

Pulsed angiolytic laser treatment of ectasias and varices in singers.

OBJECTIVES: Varices and ectasias in singers are typically the result of phonotraumatic shearing stresses and/or collision forces on the microcirculation within the superficial lamina propria. These lesions can be debilitating in performing vocalists because of the effect of recurrent hemorrhage and/or as a contributing factor to the morbidity of other mass lesions such as polyps, nodules, and cysts. Phonomicrosurgical treatment of performers is understandably approached with great trepidation, as the vocal liability of surgically disturbing the superficial lamina propria and epithelium must be balanced with the inherent detrimental vocal effect(s) of the lesion(s). Pulsed angiolytic lasers that emit radiation at high absorbance peaks of oxyhemoglobin were examined to determine whether they were an efficacious treatment approach for ectasias and varices based on these lasers' mechanisms of action and prior experience in phonomicrosurgery. METHODS: A prospective trial was done in 39 patients (40 procedures in 54 vocal folds) without complication to evaluate the effectiveness of a 585-nm pulsed dye laser (PDL; 25 cases) and a 532-nm pulsed KTP laser (15 cases) in a noncontact mode to treat 65 varices and 43 ectasias. Twenty-nine of 39 patients had varices and ectasias associated with other phonotraumatic mass lesions that required resection. RESULTS: All patients have resumed full vocal activities, and no patient has had a subsequent hemorrhage or vocal deterioration. CONCLUSIONS: Both the 585-nm PDL and the 532-nm pulsed KTP laser were found to be efficacious and relatively safe treatment modalities for vascular abnormalities of the vocal folds in singers. Noncontact selective photoangiolysis of the aberrant vessels prevented future bleeding without substantial photothermal trauma to the overlying epithelium and surrounding delicate superficial lamina propria, thereby allowing for optimal postoperative mucosal pliability and glottal sound production. However, the pulsed KTP laser was substantially easier to use because of its enhanced hemostasis due to its longer pulse width. Vessel wall rupture was commonplace during use of the 585-nm PDL, but rarely occurred during photoangiolysis with the 532-nm pulsed KTP laser.

Dilatation, Pathologic↗
PubMed2006

Office-based 532-nm pulsed KTP laser treatment of glottal papillomatosis and dysplasia.

OBJECTIVES: Treatment of glottal papillomatosis and dysplasia was mirror-guided and done in surgeons' offices in the 19th century. It migrated to the operating room in the 20th century to accommodate direct laryngoscopic surgery, which required assistants to administer anesthesia and procedural support. The primary treatment goals, which are disease regression and voice restoration and/or maintenance, are tempered by the morbidity of general anesthesia and potential treatment-induced vocal deterioration. To obviate general anesthesia, office-based laser laryngeal surgery was first done in 2001 with the 585-nm pulsed dye laser (PDL), because it employs a fiber delivery system and its energy is selectively absorbed by oxyhemoglobin. Since then, this new angiolytic laser treatment paradigm has become a mainstay of management for many surgeons; however, there are a number of shortcomings of the PDL. To further develop this concept and address the limitations of the PDL, we used a 532-nm pulsed potassium titanyl phosphate (KTP) laser. METHODS: A prospective assessment was performed on 48 patients in 72 cases of recurrent glottal dysplasia (36) or papillomatosis (36). All individuals had previously undergone microlaryngoscopic management with histopathologic evaluation. RESULTS: Two dysplasia patients did not tolerate the procedure. Of the treatable dysplasia cases, there was follow-up in 29 of 34. Disease regression was at least 75% in 18 of 29 cases (62%), 50% to 75% in 7 of 29 (24%), and 25% to 50% in the remaining 4 of 29 (14%). Papilloma patients returned for treatment when symptoms recurred, so disease regression could not be assessed accurately. Similar to data obtained with the PDL, these data confirmed that dysplastic mucosa could normalize without resection. CONCLUSIONS: Our observations revealed that the 532-nm pulsed KTP laser provided enhanced performance over the PDL laser in a number of ways. The ability to use smaller glass fibers precluded mechanical trauma to the channels of the flexible laryngoscopes and allowed for improved suctioning of secretions. Oxyhemoglobin absorbs energy better at 532 nm than at 585 nm, and the KTP laser can be delivered through a longer pulse width. These factors provide enhanced hemostasis and improved intralesional energy absorbance. Finally, unlike the PDL, the KTP laser is a solid-state laser and is not prone to mechanical failure.

Ambulatory Surgical Procedures↗
PubMed2006

Office-based and microlaryngeal applications of a fiber-based thulium laser.

OBJECTIVES: The carbon dioxide (CO2) laser is the premier dissecting instrument for hemostatic cutting and ablation during endolaryngeal surgery. However, microlaryngeal tangential dissection and office-based photoablation have been limited by the lack of a fiber-based delivery system. To address this limitation, a new laser was designed, which is a diode-pumped solid-state laser with a thulium-doped yttrium-aluminum-garnet laser rod. It produces a continuous-wave beam with a wavelength of 2013 nm and a target chromophore of water. This new laser functions similarly to a CO2 laser with the benefit of being delivered through a small glass fiber (0.365 to 0.550 mm). METHODS: A prospective pilot trial was done in 74 cases to explore applications of the new thulium laser. Thirty-two procedures were done with the laser used as an ablating instrument and topical anesthesia through a flexible laryngoscope (papillomatosis, 20; microinvasive carcinoma, 6; benign supraglottic lesions, 3; edema, 2; granuloma, (1). Forty-two procedures were done with the laser used as a cutting or ablating instrument for microlaryngeal dissection and general anesthesia. These included 27 partial laryngeal resections (supraglottis, 15; glottis, 10; subglottis, (2) and 8 posterior glottic laryngoplasties. The laser was also used as an ablative instrument during microlaryngoscopy in 7 cases. RESULTS: The thulium laser was used effectively in all cases, under both local and general anesthesia. In microlaryngeal dissection, electrocautery was not needed to control bleeding, even during cutting in the highly vascular paraglottic space. No complications related to the use of the thulium laser were experienced in any case. CONCLUSIONS: Because of the fiber-based delivery system, the 2013-nm continuous-wave thulium laser shows substantial promise for tangential dissection during microlaryngoscopy and soft tissue photoablation during office-based flexible laryngoscopy. Hemostasis was judged to be superior to experiences with the CO2 laser. In this pilot study, performing en bloc laryngeal cancer resection procedures was facilitated by use of the thulium laser.

Adult↗
PubMed2006

The use of photodynamic therapy in dermatology: results of a consensus conference.

Photodynamic therapy (PDT) has significant promise in improving outcomes of patients with a variety of cutaneous conditions. A group of experts met to review the principles, indications, and clinical benefits of PDT with 5-aminolevulinic acid (ALA). They also reviewed PDT with methyl aminolevulinate. The experts established consensus statements for pretreatment, posttreatment, ALA contact time, light sources, and numbers of sessions associated with ALA PDT for actinic keratosis and superficial basal cell carcinoma, photorejuvenation and cosmetic enhancement, acne, sebaceous skin, rosacea, and rhinophyma. They based consensus recommendations on their clinical experience and the medical literature. They also suggested future applications of ALA PDT. Experts concluded that ALA PDT is a safe and effective modality for the treatment of conditions commonly encountered in dermatology. Since downtime is minimal, the technique is suitable for patients of all ages and lifestyles. Appropriate light sources are available in many dermatology offices. The expanding clinical and financial benefits of PDT justify the purchase of an appropriate light source.

Aminolevulinic Acid↗
PubMed2005

Intradermally focused infrared laser pulses: thermal effects at defined tissue depths.

BACKGROUND AND OBJECTIVES: To produce controlled, spatially confined thermal effects in dermis. STUDY DESIGNS/MATERIALS AND METHODS: A 1 W, 1,500 nm fiber-coupled diode laser was focused with a high numerical aperture (NA) objective to achieve a tight optical focus within the upper dermis of skin held in contact with a glass window. The delivery optics was moved using a computer-controlled translator to generate an array of individual exposure spots. Fresh human facial skin samples were exposed to a range of pulse energies at specific focal depths, and to a range of focal depths at constant pulse energy. Cellular damage was evaluated in frozen sections using nitro-blue tetrazolium chloride (NBTC), a lactate dehydrogenase (LDH) activity stain. Loss of birefringence due to thermal denaturation of collagen was evaluated using cross-polarized light microscopy. The extent of focal thermal injury was compared with a model for photon migration (Monte Carlo Simulation), heat diffusion, and protein denaturation (Arrhenius model). RESULTS: Arrays of confined, microscopic intradermal foci of thermal injury were created. At high NA, epidermal damage was avoided without active cooling. Foci of thermal injury were typically 50-150 microm in diameter, elliptical, and at controllable depths from 0 to 550 microm. Both LDH inactivation and extracellular matrix denaturation were achieved. CONCLUSION: Spatially confined foci of thermal effects can be achieved by focusing a low-power infrared laser into skin. Size, depth, and density of microscopic, thermal damage foci may be arbitrarily controlled while sparing surrounding tissue. This may offer a new approach for nonablative laser therapy of dermal disorders.

Burns↗
PubMed2005

Evaluation of photochemical tissue bonding for closure of skin incisions and excisions.

BACKGROUND AND OBJECTIVES: Photochemical tissue bonding (PTB) is a new non-thermal technique for tissue repair involving application of a photochemically active dye and irradiation with visible light. The objective was to compare PTB with standard sutures and the tissue adhesive, octyl cyanoacrylate, for closure of skin incisions and excisions. STUDY DESIGN/MATERIALS AND METHODS: Incisions and excisions made on the flanks of a Hanford mini-pig were secured with subcutaneous sutures. Superficial closure methods were 3-0 monofilament sutures, PTB (Rose Bengal and green light), tissue adhesive and the combination of tissue adhesive then PTB. Wounds were evaluated 2, 4, and 6 weeks postoperatively for cosmetic outcomes and histology. RESULTS: Cosmetic outcomes and histological scar width of incisions and excisions did not differ among the treatment groups at 2, 4, and 6 weeks. CONCLUSION: PTB is as effective as standard sutures for wound closure in porcine skin in terms of cosmetic outcomes and safety.

Animals↗
PubMed2005

Long-pulsed neodymium:yttrium-aluminum-garnet laser treatment for port-wine stains.

OBJECTIVE: Laser treatment of port-wine stain (PWS) might be improved using a deeply penetrating wavelength. METHODS: PWSs in 17 patients were treated 3 times with a 595-nm pulsed dye laser (PDL) and a 1064-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. Fluences of 1.0, 0.8, and 0.6 times the minimum purpura dose (MPD) were used for Nd:YAG laser. Posttreatment biopsy specimens were taken. Blind assessment and quantitative analysis of PWS clearing were performed from digital photographs. RESULTS: MPD for Nd:YAG laser varied widely, from 40 to 250 J/cm 2 . Purpura lasted longer after PDL. Treatment achieved similar 50% to 75% clearing with both PDL and Nd:YAG laser at 1 MPD. Nd:YAG caused greater perivascular and epidermal injury. Scarring occurred in the only patient treated with a Nd:YAG fluence greater than 1 MPD. Patients preferred Nd:YAG laser because of their faster recovery. CONCLUSION: Nd:YAG laser used at MPD is as effective as PDL for treating PWS. Nd:YAG laser fluences higher than MPD may cause scarring.

Adolescent↗