Algorithm for using a long-pulsed Nd:YAG laser in the treatment of deep cutaneous vascular lesions

A feasible way to explore real blood vessels thermal responses to laser irradiation by combing optical clearing and the reflectance spectra measurements: animal experiment study

Laser therapy has been widely used to treat port-wine stains (PWS) and other cutaneous vascular lesions via selective photothermolysis. Animal models are a valuable tool for investigating thermal responses beneath the skin. However, in previous animal experiments, such as the dorsal skin chamber model, one side of the skin was removed, resulting in the loss of mechanical support for the target blood vessel. In this study, the optical clearing technique was applied to the dorsal skin, allowing direct observation of real thermal responses within the tissue without removing the covering skin. The target blood vessels were irradiated with a pulsed 1064 nm Nd: YAG laser. The corresponding thermal responses were recorded using a CCD camera. Additionally, variations in skin reflectance spectra were measured before and after laser irradiation. Due to the optical clearing and reflectance spectra measurement, vessel responses such as contraction, reperfusion, and full occlusion were correlated with specific variation patterns in reflectance spectral signals.

A Resampling Based Grid Search Method to Improve Reliability and Robustness of Mixture-Item Response Theory Models of Multimorbid High-Risk Patients

There are many statistics available to the applied statistician for assessing model fit and even more methods for assessing internal and external validity. We detail a useful approach using a grid search technique that balances the internal model consistency with generalizability and can be used with models that naturally lend themselves to multiple assessment techniques. Our method relies on resampling and a simple grid search method over 3 commonly used statistics that are simple to calculate. We apply this method in a latent traits framework using a mixture Item Response Theory (MIXIRT) model of common chronic health conditions. Model fit is assessed using Akaike's Information Criteria (AIC), latent class similarity is measured with the Variance of Information (VI), and the consistency of condition complexity and prevalence across latent classes is compared using Kendall's τ rank order statistic. From two patient cohorts at high risk for hospitalization in 2014 and 2018, we generated 19 MIXIRT models (allowing 2-20 latent classes) on 21 common comorbid conditions identified via healthcare encounter diagnosis codes. We ran these models on 100 bootstrap samples of size 10% for each cohort. Among the resulting models, combined AIC and VI statistics identified 5-7 latent classes, but the rank order correlation of condition complexity revealed that only the 5 class solutions had consistent condition complexity. The 5 class solutions were combined to produce a single parsimonious MIXIRT solution that balanced clinical significance with model fit, cluster similarity, and consistency of condition complexity.

A comparison of microvascular responses to visible and near-infrared lasers

BACKGROUND AND OBJECTIVE

Pulsed dye laser (PDL) is a commonly used treatment for Port Wine Stain birthmarks (PWS). However, deeper components of PWS are often resistant to PDL. Deeper penetrating lasers, including the long pulsed Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser have been used, but carry greater risk. This study evaluates the distinct blood vessel thermal responses to visible (595 nm) and near infrared (1,064 nm) lasers using animal and numerical models.

STUDY DESIGN/MATERIALS AND METHODS

Blood vessels in the rodent dorsal skin chamber (DSC) were irradiated by a 595 nm PDL and a long-pulsed 1,064 nm Nd:YAG laser. Laser-induced immediate and 1-hour post-structural and functional changes in the vessels were documented. Numerical simulations were conducted using a 1,000 µm depth SD mouse skin fold to simulate experimental conditions.

RESULTS

PDL irradiation produced immediate blood vessel hemorrhage. Modeling indicated this occurs due to preferential heating of the superior parts of large blood vessels. Nd:YAG irradiation resulted in blood vessel constriction; modeling indicated more uniform heating of vessel walls.

CONCLUSION

PDL and Nd:YAG lasers result in distinct tissue responses. This supports different observable clinical treatment end points when using these devices. Vessel constriction associated with the Nd:YAG may be more difficult to observe and is one reason this device may carry greater risk.

The use of long pulsed neodymium-doped yttrium aluminum garnet for the treatment of paediatric venous malformations

Background

Venous malformation in the pediatric population can present with pain, bleeding, or a debilitating deformity that can be difficult to manage. Sclerotherapy, surgery, and more recently, long pulsed neodymium-doped yttrium aluminum garnet (Nd : YAG) laser have been used with variable success rates.

Objective

Our aims and objectives, were to identify the specific group of patients that would benefit from this treatment.

Methods

A prospective clinical trial was carried out with 59 consecutive patients. The treatment criteria included a large facial deformity and painful or bleeding lesions. One to three treatments were administered at 6~8-week intervals.

Results

A total of 59 patients were treated. The average follow-up was 24 months. All patients achieved good to excellent results in pain and bleeding control as well as in the reduction of the size of lesions in the lip and oral mucosa. The treatment however, is not effective in reducing the size of large, relatively high-flow lesions in the limbs. Complications from treatment include skin blistering (n=4), ulceration (n=4), and subsequent hypertrophic scarring (n=3). Three patients had partial recurrence after a 3-year follow-up.

Conclusion

Complex venous malformations cannot be cured but can be symptomatically controlled with the long-pulsed Nd : YAG laser treatment. The treatment satisfaction is high, and there is a small but definite risk of scarring from treatment.

Laser treatment of 13 benign oral vascular lesions by three different surgical techniques

OBJECTIVES

Benign Oral Vascular Lesions (BOVLs) are a group of vascular diseases characterized by congenital, inflammatory or neoplastic vascular dilations clinically evidenced as more or less wide masses of commonly dark bluish color. If traumatized BOVLs are characterized by a great risk of hemorrhage and their treatment usually requires great caution to prevent massive bleeding. In the last decades lasers have dramatically changed the way of treatment of BOVLs permitting the application of even peculiar techniques that gave interesting advantages in their management reducing hemorrhage risks. The aim of this study was to evaluate the capabilities and disadvantages of three laser assisted techniques in the management of BOVLs.

STUDY DESIGN

In this study 13 BOVLs were treated by three different laser techniques: the traditional excisional biopsy (EB), and two less invasive techniques, the transmucosal thermocoagulation (TMT) and the intralesional photocoagulation (ILP). Two different laser devices were adopted in the study: a KTP laser (DEKA, Florence, Italy, 532 nm) and a GaAlAs laser (Laser Innovation, Castelgandolfo, Italy, 808 nm) selected since their great effectiveness on hemoglobin.

RESULTS

In each case, lasers permitted safe treatments of BOVLs without hemorrhages, both during the intervention and in the post-operative period. The minimally invasive techniques (TMT and ILP) permitted even the safe resolution of big lesions without tissue loss.

CONCLUSIONS

Laser devices confirm to be the gold standard in BOVLs treatment, permitting even the introduction of minimal invasive surgery principles and reducing the risks of hemorrhage typical of these neoplasms. As usual in laser surgery, it is necessary a clear knowledge of the devices and of the laser-tissue interaction to optimize the results reducing risks and disadvantages.

Treatment of superficial cutaneous vascular lesions: experience with the long-pulsed 1064 nm Nd:YAG laser

Recent published studies evaluating the long-pulsed 1064 nm Nd:YAG laser for superficial cutaneous vascular lesions have limited subjects and optimal treatment parameters have not been established. To determine the efficacy and safety of the long-pulsed 1064 nm Nd:YAG laser on superficial cutaneus vascular lesions and analyse retrospectively our experience of a 3-year period are the aims of this study. Over the 3-year period, 255 patients were treated [189 female and 66 male; median age 35 (range 7-65) years; Fitzpatrick skin types II-V]. Twenty-six patients with spider angioma, 130 with facial telangiectasia, and 99 with leg telangiectasia were treated. A long-pulsed 1064 nm Nd:YAG laser was used. A test dose was performed at the initial consultation and thereafter patients were reviewed and treated at 4-week intervals for 5 months. Of those patients who completed treatment and followup, 26/26 (100%) of spider angiomas, 125/130 (97%) of facial telangiectasia, and 80/99 (80,8%) of leg telangiectasia markedly improved or cleared. We suggest that the long pulsed Nd:YAG laser is a safe and effective treatment for common superficial cutaneous vascular lesions. However, it is not the first choise to use to treat superficial vessels on the face where depth is not the concern.

Clinical experience in the treatment of port-wine stains with blebs

Background

The current modality of choice for the treatment of Port-wine stains (PWS) is laser photocoagulation. Laser therapy for the treatment of PWS, especially with a pulsed dye laser (PDL), has been proven safe and effective; however, because penetration of the PDL is too shallow for an effective ablation of the blebs, treatment of blebbed PWS, using PDL, may be insufficient.

Objective

We demonstrated the clinical efficacy of a 1,064 nm long pulsed Nd:YAG laser with contact cooling device for blebbed PWS.

Methods

Twenty one patients with blebbed PWS (Fitzpatrick skin types II-V) underwent a treatment, using a 1,064 nm long pulsed Nd:YAG laser with a contact cooling device at 8-week intervals. Treatments were done using 5~6 mm spot sizes at 20~30 ms and 95~170 J/cm². Laser parameters were adjusted in order to meet the needs of each individual patient's lesions.

Results

All subjects tolerated the treatments well, and showed clinical improvement from blebs. Of the 21 patients, 18 of them experienced either moderate or excellent response.

Conclusion

Use of a 1,064 nm long pulsed Nd:YAG laser results in a greater depth of vascular coagulation. A 1,064 nm long pulsed Nd:YAG laser with contact cooling device may be regarded as a promising therapeutic option for the treatment of blebbed PWS.

Continuous low-dose-rate radiation of radionuclide phosphorus-32 for hemangiomas

The study goal was to clarify the therapeutic effect and the absorbed dose of radionuclide phosphorus-32 for skin hemangiomas and the consequent risk of side effects in these patients. Phosphorus-32 is an β emitter and is used for skin hemangioma treatment. In comparison with the few Gy per minute of the linear accelerators, the dose rate of phosphorus-32 for hemangiomas is much <1 Gy/hour; so, the latter is called low-dose-rate radiation. To achieve the therapeutic dose, continuous hours or days of radiation is necessary. For strawberry hemangiomas, the phosphorus-32 applicator was tightly placed on the lesion site for several hours until reaching therapeutic dose. The absorbed dose was estimated by radiochromic films. The absorbed dose of phosphorus-32 irradiation declined exponentially with a depth from 0 to 2.5 mm. Of the 316 patients with strawberry hemangiomas, the lesion disappeared completely within 3 months after one-time treatment in 259 cases (82%). For cavernous hemangiomas, 370KBq phosphorus-32 colloid was injected into the hemangioma each square centimeter, and the absorbed radiation was estimated by theoretical calculation. Forty-two of the 58 patients with cavernous hemangiomas (72%) had lesions that completely disappeared within 3 months after receiving one to six treatments. Thus, the phosphorus-32 for strawberry hemangiomas and the chromium phosphate-32 colloid for cavernous hemangiomas were clearly efficacious.

Neodymium:YAG laser treatment of lower leg telangiectasia: a new minimally invasive approach

The aim of this study was to validate the safety and effectiveness of a new therapeutic procedure for the treatment of lower leg telangiectasia without clinical vein insufficiency. A group of 20 healthy women aged between 24 and 47 years (mean±sem 37.05 ± 1.47) with lower leg telangiectasia without clinical vein insufficiency, previously investigated by echo colour Doppler sonography, were recruited and were treated with neodymium:YAG laser (mean±sem 2.5 ± 0.11 sessions). Good or excellent results were obtained in 16 patients and the improvements were statistically significant (p < 0.01). Out of the 20 patients, 16 were satisfied with the procedure. We strongly support laser treatment of lower leg telangiectasia since it allows injection of chemicals to be avoided, and changes the stromal microarchitecture rearranging the fibroblast network into a more resistant pattern reducing the likelihood of relapse.

Treatment using a long pulsed nd:yag laser with a pulsed dye laser for four cases of blebbed port wine stains

Port wine stains (PWS) are congenital capillary malformations consisting of ectasia of capillaries and venules. At birth,lesions are flat and relatively uniform in color, but evolve with age to become raised, thickened, irregularly surfaced, and deeply colored. Therefore, it is considered optimal to begin treatment of patients at an early age. Conventional treatment modalities, such as electrocautery or excision, require considerable effort and may be cosmetically unsatisfactory. We have performed treatment of blebbed PWS of four patients using a 1,064 nm long pulsed Nd:YAG laser with a contact cooling device. According to their size, most blebs required three or fewer treatment sessions at 8-week intervals. Treatments were well tolerated by all subjects and patients showed moderate to good improvement of blebs. A 1,064 nm long pulsed Nd:YAG laser with contact cooling may be considered as a promising therapeutic option for treatment of blebbed PWS.

Effectiveness of non-ablative three dimensional (3D) skin rejuvenation: a retrospective study involving 46 patients

BACKGROUND

Three dimensional (3D) skin rejuvenation is proposed to be effective for all skin layers. The aim of this concept is to treat sun spots with broad-band pulse light; large pores, fine lines and vascular lesions with a long-pulsed 1064 nm neodymium-yttrium-aluminum-garnet (Nd:YAG) laser system and skin ptosis and laxity with a 1100-1800 nm infrared light source.

OBJECTIVE

In this study, 46 patients treated with the 3D skin rejuvenation procedure were retrospectively evaluated to assess the effectiveness of the 3D procedure according to both patient and doctor satisfaction.

METHODS

The 3D procedure was carried out over the course of five sessions with 15 day intervals between sessions. Results were judged by an experienced laser dermatologist both by direct patient examination and by comparison of "before" and "after" photographs. Results were ranked into five categories ranging from 0 to 4. At the final control, the patients were also asked to rate their satisfaction with the procedure in five categories, ranging from 0 to 4.

RESULTS

All of our patients showed improvement, with an overall patient satisfaction score of 2.65. Female patients were more satisfied than male patients. Patient and doctor satisfaction scores were generally correlated.

CONCLUSIONS

Our clinical results indicate that the 3D procedure is an effective nonsurgical skin rejuvenation method.

Treatment of pulsed dye laser-resistant port wine stain birthmarks

The concept of selective photothermolysis with the 577-/585-nm pulsed dye laser (PDL) revolutionized treatment of relatively common port wine stain (PWS) birthmarks. The majority of PWS can be significantly lightened with the PDL. However, few PWS are lightened completely with PDL and up to 20% hardly lighten at all. PDL-resistant PWS exist in any large cutaneous laser practice and constitute a difficult management problem. This article discusses the proposed cause, and currently available and emerging options for PDL-resistant PWS. These include higher power, longer wavelength, variable pulse width lasers with selective epidermal cooling such as 595-nm PDL, 755-nm alexandrite, 810-nm diode, 1064-nm neodymium:yttrium-aluminum-garnet, and intense pulse light systems. Other promising modalities include topical and systemic photodynamic therapy, electrical optical synergy technology, pulse stacking of similar or differing wavelengths, use of optical clearing agents in conjunction with laser, and erbium laser epidermal stripping before laser treatment.

Nd:YAG lasers (1,064 nm) in the treatment of venous malformations of the face and neck: challenges and benefits

Neodymium:yttrium aluminum garnet (Nd:YAG) laser therapy for venous malformations (VMs) of the head and neck is a rather new therapeutical option in addition to sclerotherapy and surgery. One hundred forty-six patients (age 2 months to 77.5 years) with VMs in the head/neck (localized, diffuse, and multifocal) were retrospectively analyzed with regard to number and quality of treatments and laser parameters used. Of these patients, 72 had no prior treatment of any kind, and 74 were pretreated. Laser treatment of mucosa and tongue was done with a mean fluence of 103.1 J/cm(2), of skin with 90.7 J/cm(2), and of glomuvenous malformations with 81.2 J/cm(2). Complex VM can mostly be controlled but rarely cured. Initial Nd:YAG laser therapy is important in the treatment of VMs regarding shrinkage of the tissue, discoloration, and induction of the desired dermal fibrosis that facilitates the surgical handling of the skin and reduces the risk of skin loss in surgery and sclerotherapy.

Laser therapy of vascular lesions

Since the first construction of a laser by Maiman in 1960 and the first clinical application of a laser in the therapy of skin lesions by Leon Goldman, laser therapy has become an important therapeutic modality in dermatology. Various lasers can be used for the treatment of different vascular and non-vascular lesions. According to our results, vascular lesions constitute the most important indication for laser therapy in dermatology.

Long-pulsed Nd:YAG laser treatment of venous lakes: report of a series of 34 cases

BACKGROUND

Some venous lakes do not respond well to traditional vascular lasers. The Nd:YAG laser output at 1,064 nm is less well absorbed by hemoglobin but penetrates more deeply into tissue.

OBJECTIVE

This study was undertaken to assess the effectiveness of the long-pulsed Nd:YAG on venous lakes.

METHODS

Thirty-five consecutive adult patients presenting with a venous lake were studied. Four patients had failed to respond to polidocanol 1% sclerotherapy, and 1 patient to pulsed dye laser. Long-pulsed Nd:YAG was administered via a water-cooled tip. Either a 3-mm spot at 250 J/cm(2) and 55 ms or a 5-mm spot at 140 to 180 J/cm(2) was used depending on the size of the lesion. Clinical end points were characterized by hardening of the lesion, central blackening, minimal whitening of the periphery, and in most cases, an audible popping sound. Responses were assessed visually in 50% of cases or by phone contact in the remaining 50% if the lesion had completely disappeared. One patient was lost to follow-up.

RESULTS

After a single treatment, 94% cleared completely; incomplete clearance occurred in 6%. There were no reported complications.

CONCLUSIONS

The long-pulsed Nd:YAG laser is highly effective treatment for venous lakes of the lip and cheeks.

Laser Treatment of Cutaneous Vascular Anomalies

BACKGROUND

Lasers and light-based therapy have been used to treat port-wine stains and hemangiomas for the past two decades.

METHODS AND RESULTS

Laser treatment produces dramatic clearing of port-wine stains with minimal scarring or epidermal damage, minimizes hypertrophy of lesions, decreases the risk of bleeding from pyogenic granlomas, and reduces the associated psychosocial morbidity. Lasers are used to halt the proliferation of the superficial component of hemangiomas, reduce the mass of the lesions, and to treat the vascular ectasia as well as the atrophic scarring that develops following involution.

CONCLUSION

Laser therapy provides a safe and effective modality with low morbidity for cutaneous vascular anomalies.

Bilddatengestützte Navigation zur Steuerung der interstitiellen Lasertherapie von vaskulären Malformationen im Kopf- und Halsbereich / Image-guided Interstitial Laser Treatment of Vascular Malformations in the Head and Neck

Laser-induced interstitial thermal therapy (LITT) is a proven minimally invasive surgical technique for the treatment of haemangiomas and vascular malformations, and various tumours. The intra-lesion application of thermal energy destroys regional tissue. The percutaneous placement of the laser fibre for photocoagulation is done without the benefit of direct visual control. Image-data-based LITT was performed in patients (five procedures) with extensive venous malformations in the maxillofacial area. The system comprised a specially developed Nd:YAG laser fibre introducer set used in conjunction with fused high-resolution computed tomography, and magnetic resonance image-data--based surgical navigation. In all cases, follow-up examination clearly showed a diminishment in tumour volume, and all patients reported significant subjective improvement. The results suggest that navigation-guided LITT can be performed safely, preserving vital structures from collateral thermal damage.