Is a 4 J/cm2 PpIX-Weighted Simulated Daylight (SDL-PDT) Dose Still Efficient for Photodynamic Therapy of Actinic Keratosis?

Background: Several solutions are now proposed to provide indoor illumination with so-called artificial white light or simulated daylight (SDL-PDT), resulting in an effective treatment for actinic keratosis (AK). However, the optimal PpIX-weighted light dose is still debated. Integrating the effective irradiance over the irradiation time yields the effective light dose, which is also known as the protoporphyrin IX-weighted light dose and is a key parameter for the efficacy of the treatment. Objectives: The paper aims to report the clinical outcomes of SDL-PDT when using the PpIX-weighted light dose of 4 J/cm2, in patients treated for AK lesions of the scalp or the face at our medical dermatology center (ClinicalTrials.gov NCT052036). Methods: A total of 30 patients (16 males, 14 females), with a mean age of 71.0 ± 10.2, with phototype 1 (16 patients) and phototype 2 (14 patients) with grade I-II AK were treated with a drug light interval (DLI) of 10 min and a light exposure of 35 min (Dermaris, Surgiris, Croix, France), corresponding to a PpIX-weighted light dose of 4 J/cm2. The primary endpoint was the cure rate of patients at six months post-treatment. Secondary endpoints included scores of pain, erythema, crusts, and discomfort during or/and post the treatment. Results: In total, 762 AK were treated. Six months following treatment, the cure rate of the patients was 77%. The median pain score was less than 1 out of 10 for most of the patients. Erythema was observed in all patients and lasted 3 days (±1.5 day). Crusts were seen in 28 patients. Discomfort was reported as mild or less in more than 97% of patients. Conclusions: The shortening of the PpIX-weighted light dose to 4 J/cm2, corresponding to an illumination duration of 35 min with the Dermaris, does not modify the efficacy of the SDL-PDT. This observation is in agreement with recent published data demonstrating that the light dose can be reduced. Furthermore, this clinical study confirmed that SDL-PDT is an effective and nearly painless treatment with minimal side effects for patients with AK lesions of the scalp.

Treatment of acne scarring with a novel dual-wavelength laser.

BACKGROUND: Facial acne scarring is a prevalent disease with both physical and psychosocial sequelae. AIMS: This study aims to evaluate an innovative solid state dual wavelength 1,319 and 589 nm laser, which does not require consumable dye, for the treatment of acne scars. PATIENTS/METHODS: A total of 12 patients (11 female, 1 man - Fitzpatrick skin phototypes II & III) with acne scar for more than one year, were treated with 1319 nm and subsequently by 589 nm, all having four-sessions, one every other week. A full face was covered in approximately 30 minutes. Acne scars were scored by one physician evaluator using the ECCA grading scale before, 2 weeks after each treatment and 1 month and 6 months after the 4th treatment. Safety was measured by recording subject discomfort scores and adverse effects. RESULTS: 12 subjects were enrolled into the study, 10 completed all 4 treatments and 2 were lost to follow up. Fluence used was 28 J/cm² ± 2.4 J/cm² at 1,319 nm and 16 ± 2.9 J/cm² at 589 nm. At baseline, mean ECCA score was 98 ± 23. This score was reduced to 88 ± 30 (p<0.02), after one session, to 68 ± 21 (p<0.01) after 2 sessions, to 58 ± 17 (p<0.01) after 3 sessions to reach 58 ± 15 (p<0.01) 1 month after the 4th and finally 66 ± 11 (p<0.01) at 6 month follow up. This observation corresponds respectively to 14%, 33%, 42%, 40% and 30% reduction of the ECCA score. Only one patient (ECCA score: 120) did not improve after 3 sessions. Slight to moderate erythema was sometimes observed without dryness or bruising. No or minimal burning or stinging was reported. No crust was observed. CONCLUSION: Improvement in scarring was noted in almost all patients with minimal discomfort and minimal downtime. Combining both minimal side effects with effective acne scar reduction, this laser appears to be highly effective. Long-term evaluation remains necessary to confirm the efficacy of this new laser.

Treatment of a vulvar Paget's disease by photodynamic therapy with a new light emitting fabric based device.

INTRODUCTION: The non-invasive vulvar Paget's disease is an intra-epidermal carcinoma with glandular characteristics. It appears like an erythematous plaque. The main symptoms are pruritus and pain. The standard treatment is surgical excision in depth. This treatment is complicated with a severe morbidity and photodynamic therapy can be an alternative choice. However, the pain experienced during the photodynamic treatment of vulvar lesion is intense and leads to a premature interruption of the treatment. The light emitting fabric is a part of a device under clinical evaluation for the treatment of actinic keratosis with photodynamic therapy. We report the observation of a vulvar Paget's disease treated by this device with a satisfactory result and an excellent tolerance. CLINICAL OBSERVATION: The patient has been diagnosed with non-invasive vulvar Paget's disease for 25 years. The disease recurred constantly despite several imiquimod applications, LASER treatments and conventional photodynamic therapy. These procedures were complicated with intense pain. To improve the tolerance, we performed three PDT sessions a month apart using a 16% methyl-aminolevulinate cream (Metvixia® Galderma, Lausanne, Switzerland) with the light emitting fabric at low irradiance (irradiance = 6 mW/cm2 -fluence = 37 J/cm2 ) with a satisfactory result and an excellent tolerance. DISCUSSION: There are no controlled trials evaluating the efficacy of photodynamic therapy in the treatment of vulvar Paget's disease. The treatment and follow-up protocols in the literature are heterogeneous. Pain is the most common side effect with greater intensity for perineal locations where photodynamic therapy is impractical outside of anesthesia or hypnosis. CONCLUSION: We report the case of a multirecidivant non-invasive vulvar Paget's disease treated with a satisfactory result and an excellent tolerance by the new light emitting fabric device. A specific study is required but the light emitting fabric could be indicated for the treatment of Paget disease of perineal location. Lasers Surg. Med. 49:177-180, 2017. © 2017 Wiley Periodicals, Inc.

Intrapleural Photodynamic Therapy for Mesothelioma: What Place and Which Future?

In the surgical multimodal management of malignant pleural mesothelioma, it seems crucial to proceed with an efficient local adjuvant treatment to kill residual tumor cells. Intrapleural photodynamic therapy has recently emerged as a potential candidate in this goal. In this review, we analyzed and classified 16 articles in which patients with malignant pleural mesothelioma received intrapleural photodynamic therapy after maximal surgical resection. The toxicity, effect on survival, and development of the technique were assessed. After two decades of clinical studies, intrapleural photodynamic therapy after surgical resection became a safe treatment that significantly improved the survival of patients.

Laser-assisted lipolysis for neck and submental remodeling in Rohrich type IV patients: fact or fiction?

BACKGROUND: Since the first studies by Apfelberg in 1994 and the mathematical model of Mordon introduced in 2004, laser-assisted lipolysis (LAL) has been on the rise. In a previous study, we presented our results in patients treated with LAL for Rohrich type I to III aging neck. The average cervicomental angle decreased from 152.6 ± 5.9 to 123.6 ± 8.8 degrees after LAL. This demonstrated a systematic decrease in fat thickness, and improved skin tightening. OBJECTIVE: This new protocol focuses solely on LAL in the Rohrich type IV aging neck. METHODS: Between June 2012 and February 2013, a prospective study was performed on 10 patients treated with LAL for Rohrich type IV aging neck. The laser used in this study was a 1470 nm diode laser (Alma Lasers, Caesarea, Israel). Laser energy was transmitted through a 600 µm optical fiber and delivered in a continuous mode, at 15 W power. Previous mathematical modeling suggested that 0.1 kJ was required in order to destroy 1 ml of fat. Patients were asked to fill out a satisfaction questionnaire. The cervicomental angle was measured 6 months postoperatively, and compared with the preoperative values. RESULTS: No seromas were observed, but prolonged edema was observed in two patients. Pain during anesthesia and discomfort after the procedure were minimal. The average cervicomental angle decreased from 191.5 ± 5.7 to 164.9 ± 14.2 degrees (p < 0.01). This demonstrated a systematic decrease in fat thickness and improved skin tightening. Even though the cervicomental angle was higher than 140° in each case, the investigators, in agreement with the patients, decided to perform a complementary surgery with platysma muscle advancement and plication six months after LAL, in only two of the ten patients. This complementary surgery led to a mean cervicomental angle of 140.2 ± 11.4, and fair satisfaction of both patients and investigators. CONCLUSION: LAL alone appears insufficient for complete remodeling in Rohrich type IV aging neck. While LAL alone is sufficient for Grade I to III, a complementary surgery must be added for Grade IV.

New treatment options for onychomycosis.

Onychomycosis is the most common nail disorder. The causative pathogens are not only dermatophytes in the majority of cases (Trichophyton rubrum and T. mentagrophytes), but also yeasts of the genus Candida and molds. A wide variety of topical antifungal agents are proposed for first-line treatment of superficial onychomycosis, when the matrix is not involved. New treatment options using light were recently introduced, such as thermal lasers, non-thermal lasers, and photodynamic therapy. For thermal lasers, a temperature increase in the nail of around 50 °C seems to be a prerequisite for success. For non-thermal lasers, the clinical data are very debatable and their mechanism of action still remains mysterious. For photodynamic therapy, 5-aminolevulinic acid is used. The therapy consists of exciting protoporphyrin IX with red light that penetrates relatively deeply. Further clinical studies of larger series of patients and with longer follow-up are still needed to reach a definitive conclusion on the value of these devices.

Laser assisted lipolysis for neck and submental remodeling in Rohrich type I to III aging neck: a prospective study in 30 patients.

BACKGROUND: Since the first studies by Apfelberg in 1994 and the mathematical model by Mordon in 2004, laser lipolysis (LAL) has been on the rise. Laser lipolysis has the advantages of reduced operator fatigue, excellent patient tolerance, quick recovery time, as well as the additional benefit of dermal tightening. This article reports our experience with laser-assisted lipolysis (LAL) in submental and neck remodelling. METHODS: Between June 2010 and January 2013, a prospective study was performed on 30 patients treated for Rohrich type I to III aging neck, with LAL. The laser used in this study was a 980 nm diode laser (Quanta system, spa model D-plus, Solbate Olona (VA), Italy). Laser energy was transmitted through a 600 µm optical fiber and delivered in a continuous mode 15 W power. Previous mathematical modelling suggested that 0.1 kJ was required in order to destroy 1 ml of fat. Patients were asked to fill out a satisfaction questionnaire. The cervicomental angle was measured 6 months post-operatively and compared with the preoperative values. RESULTS: Other than three patients who developed mild hyperpigmentation that disappeared after 4 months, there were no complications in the series. Pain during the anaesthesia and discomfort after the procedure were minimal. The time taken to return to normal activities was 3.2 ± 1 days. All patients would strongly recommend this treatment. Overall satisfaction was high with both patients and investigators and was validated by decrease in cervicomental angle demonstrating a systematic decrease in fat thickness and improved skin tightening. CONCLUSION: LAL is a safe and reproducible technique for remodeling in Rohrich type I to III aging neck. The procedure allows for a reduction in the amount of adipose deposits while providing concurrent skin contraction.

New treatment techniques for axillary hyperhidrosis.

Hyperhidrosis is a medical problem defined as perspiration in excess of what is normally needed to cool the body. The excessive production of sweat by the sudoriferous glands is independent of the process of thermoregulation. Techniques have recently appeared that make use of energy sources, in particular microwave devices and light (pulsed flashlamp or laser). The aim is to obtain very long-lasting efficacy without notable side effects. Thermal Nd:YAG lasers used with an interstitial fiber, microwave devices, and photodynamic therapy appear to offer new treatment options for axillary hyperhidrosis. However, insertion of a laser fiber into tissue by means of a cannula may lead to complications if the procedure is not well mastered, as has been shown by numerous studies on laser lipolysis. The only microwave device available on the market is certainly interesting. Photodynamic therapy using eosin gel is an attractive technique. The energy source is a pulsed flashlamp, which many physicians have. Eosin gel is relatively easy to produce and these gels are already marketed in several countries. However, further clinical studies of larger series of patients and with longer follow-up are still needed to reach a definitive conclusion as to the value of this approach.

Commonly used fiber tips in endovenous laser ablation (EVLA): an analysis of technical differences.

Many different types of fiber tips have been developed over the last few years to be used in endovenous laser ablation (EVLA) procedures. All these new but different tips claim a certain superiority over the other tips. Evidence for a best tip is however lacking. Four of these fiber tips have been compared in this article: (1) the bare fiber, (2) the Tulip-Tip, (3) the NeverTouch™ tip, and (4) the radially emitting tip. The aim of this paper is to provide information on the technical differences between these fiber tips and differences in their underlying heat transfer mechanisms. Although all tips are effective in the primary goal of EVLA, namely to occlude the incompetent vein, they differ in side effects, they differ in side effects, practicality, and cost. Although these new tips have improved EVLA, the perfect tip is not on the market yet.

Photodynamic therapy of malignant brain tumours: a complementary approach to conventional therapies.

The poor outcome of primary malignant brain tumours is predominantly due to local invasion and local recurrence and their prognosis is highly dependent on the degree of resection. They have no border and, at best, a marginal zone that remains invisible to the surgeon. Photodynamic therapy (PDT) appears to be an interesting modality to fill the need for a targeted treatment that may reduce recurrence and extend survival with minimal side effects. In this review, we summarize the different technologies of brain tumour PDT employed such as interstitial PDT, and PDT-associated surgical resection, describing new light delivery devices. The role of dosimetry - one of the key factors behind successful brain tumour PDT - is discussed. This can be achieved by integrating results from in vivo studies. In this context, the development of new therapeutic photosensitizer delivery systems is also an area of significant research interest. Multifunctionality can be engineered into a single nanoplatform to provide tumour-specific detection, treatment, and follow-up. Such multitasking systems appear to be complementary to conventional technologies.

New design of textile light diffusers for photodynamic therapy.

A homogeneous and reproducible fluence delivery rate during clinical photodynamic therapy (PDT) plays a determinant role in preventing under- or overtreatment. PDT applied in dermatology has been carried out with a wide variety of light sources delivering a broad range of more or less adapted light doses. Due to the complexities of the human anatomy, these light sources do not in fact deliver a uniform light distribution to the skin. Therefore, the development of flexible light sources would considerably improve the homogeneity of light delivery. The integration of plastic optical fiber (POF) into textile structures could offer an interesting alternative. In this article, a textile light diffuser (TLD) has been developed using POF and Polyester yarns. Predetermined POF macrobending leads to side emission of light when the critical angle is exceeded. Therefore, a specific pattern based on different satin weaves has been developed in order to improve light emission homogeneity and to correct the decrease of side emitted radiation intensity along POF. The prototyped fabrics (approximately 100 cm(2): 5×20 cm) were woven using a hand loom, then both ends of the POF were coupled to a laser diode (5 W, 635 nm). The fluence rate (mW/ cm(2)) and the homogeneity of light delivery by the TLD were evaluated. Temperature evolution, as a function of time, was controlled with an infrared thermographic camera. When using a power source of 5 W, the fluence rate of the TLD was 18±2.5 mw/cm(2). Due to the high efficiency of the TLD, the optical losses were very low. The TLD temperature elevation was 0.6 °C after 10 min of illumination. Our TLD meets the basic requirements for PDT: homogeneous light distribution and flexibility. It also proves that large (500 cm(2)) textile light diffusers adapted to skin, but also to peritoneal or pleural cavity, PDTs can be easily produced by textile manufacturing processes.

A comparative study of the efficacy of endovenous laser treatment of the incompetent great saphenous under general anesthesia with external air cooling with and without tumescent anesthesia.

BACKGROUND: This clinical study reports our experience with endovenous laser treatment (ELT) in which external air cooling is used without classic tumescent anesthesia. METHODS: Two hundred thirty-two patients underwent ELT under general sedation. In group A (n = 192), ELT was performed with air cooling but without the concurrent use of tumescent anesthesia. In group B (n = 40), patients were treated using the traditional tumescent technique. The parameters were similar for both groups: 980-nm diode laser, power of 15 W, and pulse duration of 1 second. The laser fiber and catheter were manually withdrawn in 3-mm increments. Ultrasound was performed to reevaluate vein closure at the end of surgery and 2 and 8 weeks and 1 year after. During follow-up, complications such as burns, dyschromia, pain, and dysesthesia, as well as time used for surgery were recorded. RESULTS: A 96% closure rate was obtained in groups A and B at 2 and 8 weeks. This rate remained stable 1 year after the ELT procedure. Except for a higher percentage of ecchymoses in group B (55%) than in group A (0%) (p < 0.001), no significant differences were observed for complications. With external air cooling, ELT took 17.5 minutes to perform for the whole leg, compared with 38.5 minutes when using tumescent anesthesia (p < 0.05). CONCLUSION: ELT surgery for the great saphenous vein can be safely performed using the air cooling method and is as efficacious as ELT done with tumescent anesthesia but takes significantly less time to perform.

980-nm laser lipolysis (LAL): About 674 procedures in 359 patients.

BACKGROUND: Since the first studies by Apfelberg in 1994, laser lipolysis (LAL) has been on the rise. Laser lipolysis leads to reduced operator fatigue, excellent patient tolerance, quick recovery time, as well as the additional benefit of dermal tightening. This article reports a 5-year experience of LAL and underlines the potential evolutions of the technique. METHODS: Between January 2006 and December 2010, 674 LAL procedures in 359 patients were performed at the Antoni De Gimbernat Foundation in collaboration with the French National Institute of Health and Medical Research (INSERM) U703. LAL was performed with a 980-nm diode laser after tumescent anaesthesia. The following laser settings were used: 600-µm optical fiber, continuous mode, power depending on individual body areas (18-40 W). The cumulative energy used for each area was recorded. Early and late complications were defined and reviewed for the whole series. Satisfaction was assessed by the patients using a visual analogue scale from 0 (unsatisfied) to 10 (highly satisfied). RESULTS: Mean cumulative energy ranged from 12 to 60 kJ. Ecchymoses were observed in all patients but resolved in less than 10 days. A touch up was needed in four patients to remove small cushions of fat missed. Mean patient satisfaction ranged from 6/10 to 9.5/10 depending on the treated area. Moreover, all patients reported they would be willing to undergo the procedure again, if needed. CONCLUSION: 980-nm LAL appears to be a safe, effective and reproducible alternative to conventional lipoplasty. However, refinements in dosimetry should be developed in order to optimise outcomes.

Endovenous laser ablation: a review of mechanisms of action.

BACKGROUND: The aim of this article is to summarize and review the proposed theories on the laser action during endovenous ablation. METHODS: Laser mechanics and laser-tissue interaction are summarized from articles found in literature. Several theories, like the "steam bubble theory," the "direct contact theory," the "heat pipe," and "direct light energy absorption" are discussed. RESULTS: The laser light emitted intraluminally can be absorbed, scattered, or reflected. Reflection is negligible in the near-infrared spectrum. By combining absorption and scattering, the optical extinction of different wavelengths related to different biological tissues can be determined. The direct contact of the fiber tip and the vein wall may be a way of destroying the vein wall, but results in ulcerations and perforations of the vein wall. Avoiding this contact, and allowing direct light absorption into the vein wall, results in a more homogenous vein wall destruction. If the energy is mainly absorbed by the intraluminal blood, the laser fiber will act as a heat pipe. Histological studies show that a more circumferential vein wall destruction can be obtained when the vein is emptied of its intraluminal blood. The use of tumescent liquid reinforces spasm of the vein and protects the perivenous tissue. CONCLUSION: Several factors play an important role in the mechanism of endovenous laser ablation. Direct energy absorption by the vein wall is the most efficient mechanism. It is important to empty the vein of its intraluminal blood and to inject tumescent liquid around the vein.

Cartilage reshaping for protruding ears: a prospective long term follow-up of 32 procedures.

BACKGROUND: Correction of prominent ears is a common plastic surgical procedure. We introduced a new non-invasive laser-assisted cartilage reshaping (LACR) technique as an alternative to invasive surgical otoplasty. METHODS: Since our first report in 2006, 32 LACR procedures in 17 patients have been performed at the Antoni De Gimbernat Foundation in collaboration with the French National Institute of Health and Medical Research (INSERM) U703. For 15 patients, the procedure was bilateral, for the remaining 2 patients LACR was performed only on one side. The treatment consisted of seven stacked pulses (3 ms, 2 Hz, 84 J/cm(2) cumulative fluence) applied using a 4-mm spot hand piece. Early and late complications were defined and reviewed for the whole series. Satisfaction was assessed by the patients using a visual analogue scale from 0 (unsatisfied) to 10 (highly satisfied). The superior and middle cephaloauricular distances were prospectively evaluated. RESULTS: Except for two cases of dermatitis, there were no early complications and no late complications (like keloids) in the series. The mean superior and middle cephaloauricular distances were, respectively, 12.3 ± 1.9 and 13.7 ± 1.6 mm compared to 17.8 ± 3.1 mm (p < 0.01) and 23.9 ± 1.9 mm (p < 0.01) before operation. Mean patient satisfaction was 8.6/10 with all patients reporting that they would be willing to undergo the procedure again, if required. CONCLUSION: LACR appears to be a safe and reproducible method for the treatment of protruding ears. Other applications of this technique, like laser assisted septal cartilage reshaping (LASCR) for septum deviation, have been recently described.

Focal laser ablation of prostate cancer: numerical simulation of temperature and damage distribution.

BACKGROUND: The use of minimally invasive ablative techniques in the management of patients with low grade and localized prostate tumours could represent a treatment option between active surveillance and radical therapy. Focal laser ablation (FLA) could be one of these treatment modalities. Dosimetry planning and conformation of the treated area to the tumor remain major issues, especially when, several fibers are required. An effective method to perform pre-treatment planning of this therapy is computer simulation. In this study we present an in vivo validation of a mathematical model. METHODS: The simulation model is based on finite elements method (FEM) to solve the bio-heat and the thermal damage equations. Laser irradiation was performed with a 980 nm laser diode system (5 W, 75 s). Light was transmitted using a cylindrical diffusing fiber inserted inside a preclinical animal prostate cancer model induced in Copenhagen rats. Non-enhanced T2-weighted and dynamic gadolinium-enhanced T1-weighted MR imaging examinations were performed at baseline and 48 hours after the procedure. The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C. RESULTS: The mean volume of the tissue necrosis, estimated from the histological analyses was 0.974 ± 0.059 cc and 0.98 ± 0.052 cc on the 48 h MR images. For the simulation model, volumes were: 1.38 cc when T = 43° C, 1.1 cc for T = 45°C and 0.99 cc when T = 50 C°. CONCLUSIONS: In this study, a clear correlation was established between simulation and in vivo experiments of FLA for prostate cancer.Simulation is a promising planning technique for this therapy. It needs further more evaluation to allow to FLA to become a widely applied surgical method.

Laser-induced primary and secondary hemostasis dynamics and mechanisms in relation to selective photothermolysis of port wine stains.

BACKGROUND: Superficial vascular anomalies such as port wine stains are commonly treated by selective photothermolysis (SP). The endovascular laser-tissue interactions underlying SP are governed by a photothermal response (thermocoagulation of blood) and a hemodynamic response (thrombosis). Currently it is not known whether the hemodynamic response encompasses both primary and secondary hemostasis, which platelet receptors are involved, and what the SP-induced thrombosis kinetics are in low-flow venules. OBJECTIVES: To (1) define the role and kinetics of primary and secondary hemostasis in laser-induced thrombus formation and (2) determine which key platelet surface receptors are involved in the hemodynamic response. METHODS: 532-nm laser-irradiated hamster dorsal skin fold venules were studied by intravital fluorescence microscopy following fluorescent labeling of platelets with 5(6)-carboxyfluorescein. Heparin and fluorescently labeled anti-glycoprotein Ib-α (GPIbα) and anti-P-selectin antibodies were administered to investigate the role of coagulation and platelet receptors, respectively. Lesional sizes were quantified by software. RESULTS: Laser irradiation consistently produced sub-occlusive thermal coagula. Thrombosis was triggered in all irradiated venules in a thermal coagulum-independent manner and peaked at 6.25min post-irradiation. Heparin decreased the maximum thrombus size and caused thrombosis to reach a maximum at 1.25min. Immunoblocking of GPIbα abated the extent of thrombosis, whereas immunoblocking of P-selectin had no effect. CONCLUSIONS: The hemodynamic response ensues the photothermal response in a thermal coagulum-independent manner and involves primary and secondary hemostasis. Primary hemostasis is mediated by constitutively expressed GPIbα but not by activation-dependent P-selectin.

1.9 µm diode laser assisted vascular microanastomoses: Experience in 40 clinical procedures.

BACKGROUND: Since the initial work of Jacobson and Suarez in 1960, microsurgery has evolved greatly. In 2009, we reported our clinical experience with 1.9 µm diode laser-assisted vascular microanastomoses (LAMA) for free flap reconstruction. In this report, the ongoing study is now expanded to include 11 additional procedures which were analyzed prospectively with a focus on the duration of the LAMA technique. METHODS: In total, 40 clinical procedures with LAMA have been performed since 2005. Mean follow-up was 3.3 years (range 0.5-5.5 years). Among those, 11 procedures were performed and prospectively analyzed during the period 2008-2009. LAMA was performed with a 1.9 µm diode laser after placement of equidistant stitches. For vessels size <1.5 mm, the following laser parameters were used: spot size 400 µm, five spots for each wall, power 125 mW, arterial/venous fluence 100/90 J/cm(2) (spot duration 1/0.9 seconds). RESULTS: For the last observed 11 procedures, mean occlusion time of the flap arterial and venous anastomoses was 5.4 ± 0.4 and 6.8 ± 0.7 minutes respectively. One anastomosis required a secondary laser application. Arterial and venous patency rates were 100% at the time of surgery. The success rate for the 11 procedures was 100%. The global success rate of the series (97.5%) is discussed and compared with the literature. CONCLUSION: The success rates for reconstructive free flap surgery realized with LAMA appear excellent. Technical innovation will most likely lead to widespread use of the handpiece laser in the operating room.

Laser preconditioning on cranial bone site: analysis of morphological vascular parameters.

BACKGROUND AND OBJECTIVES: Bone vascularization is a key factor in the bone healing process following X-ray irradiation. Preserving the vascular network from X-ray-induced injury is a relevant approach in the promotion of bone healing. Previously, we developed a protocol of laser preconditioning (810 nm diode laser, 36 J/cm²) prior to X-ray radiation (18.75 Gy) which protects the bone vascular network from deleterious effects of X-ray radiation. The aim of this present work is to characterize the effects of laser preconditioning on the bone through a morphological analysis of vascular parameters. MATERIALS AND METHODS: Digital images of the vascular plexus were taken through an optical bone chamber which was implanted onto the calvaria of rabbits. Bespoke software was used for the quantification of the vessels (classified in four groups according to their diameter), vessel length, and number of nodes at weeks 0, 4, and 8. Twenty rabbits were divided into four groups: control group #1 (n = 5); laser group #2 (n = 5). X-ray radiation group #3 (n = 5), laser preconditioning 24 hours prior to X-ray radiation group #4 (n = 5). RESULTS: The bone vascular network was stable for groups #1 and #2. Statistical analysis showed a significant reduction of each observed vascular parameter for groups #3 and #4. In the laser preconditioned group #4 the loss was less marked than in the X-ray group #3, especially for large vessels (diameter >50 µm). DISCUSSION AND CONCLUSION: We provide in vivo microcirculatory evidence to support the concept of laser preconditioning of bone. A computer-based semi-automatic system is described to quantify superficial bone vascular network parameters that had been treated by laser preconditioning prior to X-ray radiation. Laser preconditioning significantly attenuates the deletion of the superficial bone vascular network irradiated by X-ray, especially concerning large diameter vessels.