Lasers in Surgery and Medicine最新文献

Objectives: Diabetes is one of the most significant chronic metabolic disorders, and diabetic foot ulcers (DFUs) are recognized as one of the most serious complications of this disease due to delayed healing, increased risk of infection, and potential limb amputation. In recent years, noninvasive physical therapies such as low-level laser therapy (LLLT) and polarized light therapy (PLT) or Bioptron have emerged as novel approaches to stimulate wound healing. This study aimed to evaluate and compare the effectiveness of these two therapeutic modalities on the healing process of skin wounds in a diabetic animal model.

Materials and methods: Forty-five male Wistar rats were rendered diabetic using streptozotocin (STZ) and subsequently divided into three groups: control, LLL-treated, and PL-treated. A standardized circular wound was created on the dorsal region of each animal, and treatments were administered daily for seven consecutive days. Wound healing was assessed on Days 0, 3, 5, 7, 14, and 21 using macroscopic analysis and microscopic evaluation on Days 7, 14, and 21 using H&E and Masson's trichrome staining.

Results: LLLT significantly enhanced tissue architecture by stimulating fibroblast activity, promoting angiogenesis, and increasing cellular proliferation. On the other hand, PLT was more effective in reducing wound dimensions and improving the macroscopic healing index. The control group indicated slower and incomplete healing.

Conclusion: Both therapeutic approaches have shown potential to accelerate diabetic wound healing, albeit through distinct mechanisms. The treatment of choice is LLLT for deep wounds and PLT for superficial wounds.

Objectives: To review the efficacy and safety of the dual 1550-nm erbium glass fiber and 1927-nm thulium fiber non-ablative fractional laser system in patients with skin of color (ie, Fitzpatrick skin types [FSTs] III-VI).

Materials and methods: Efficacy, safety, and histologic outcomes were reviewed from 15 clinical studies examining the use of the 1550-nm or 1927-nm wavelength treatment in individuals with skin of color.

Results: Despite variability across study designs, consistent improvement was reported with the 1550-nm wavelength for the treatment of scarring and melasma and the 1927-nm wavelength for the treatment of melasma and photoaging. Postinflammatory hyperpigmentation (PIH) rates varied across studies. Studies directly comparing different settings reported reduced PIH rates with lower energy and/or density. Histologic studies confirmed dermal remodeling and reduced melanin after treatment.

Conclusion: The 1550/1927-nm dual-laser system is safe and effective. Reducing pulse energy and density may confer fewer adverse effects in patients with skin of color. Additional studies are needed, particularly for patients with FST VI and the 1927-nm wavelength treatment.

Objective: To examine how serial line-field optical coherence tomography (LC-OCT) imaging can visualize early tissue-response patterns following UltraClear Laser-Coring treatment in a single-subject self-imaging model, with secondary evaluation of the impact of a regenerative serum.

Methods: A single subject self-imaging demonstration was performed using 2910 nm UltraClear Laser-Coring treatments applied to bilateral volar forearms. The left arm received a regenerative serum, while the right arm received petroleum jelly and served as a comparator. Serial dermoscopy and LC-OCT imaging (deepLive LC-OCT system Damae Medical, Paris, France) was performed from Day 1 to Day 18 to document the imaging characteristics of laser-created microchannels over time. LC-OCT features of interest included keratinocyte behavior, nuclear morphology, stratum corneum reformation, and dermal remodeling.

Results: LC-OCT enabled visualization of progressive epithelial coverage over the laser-induced microchannels, with near-complete surface continuity apparent by Day 4. Stratum corneum-like hyperreflective layering reappeared between Days 4 and 18. Nuclear contour and reflectivity changes on LC-OCT corresponded to expected patterns of cellular activation and maturation. Dermal vessel dilation and increasing fiber definition were observed between Days 8 and 18. No meaningful differences in LC-OCT appearance were observed between serum-treated and control sites.

Conclusions: LC-OCT proved effective for documenting the in vivo imaging features associated with UltraClear Laser-Coring treatment. Serial LC-OCT imaging revealed distinct epidermal and dermal healing patterns. This technical demonstration supports the feasibility of using LC-OCT to visualize laser-induced tissue effects in real time.

Objectives: To report a novel, multimodal approach using nonablative fractional laser (NAFL) therapy followed by surgical debulking to treat disfiguring facial scarring secondary to hidradenitis suppurativa (HS) in a patient with skin of color.

Materials and methods: A 33-year-old man with a history of severe HS presented with extensive cribriform scarring involving the bilateral cheeks, temples and mandibular areas. After medical optimization, he underwent 3 monthly sessions of 1540 nm NAFL (Palomar Starlux) followed by conservative surgical debulking of residual hypertrophic tissue.

Results: At 1-month follow-up, the patient demonstrated marked clinical improvement in scar texture, pigmentation, and contour with no adverse effects. Compared to baseline, there was a notable reduction in hypertrophy, flattening of papillomatous lesions, and improved cosmesis overall. Importantly, the patient also reported a significant improvement in pain and quality of life.

Conclusion: This case illustrates the safety and efficacy of NAFL in combination with surgical debulking for scar remodeling in HS, particularly in patients with skin of color, for whom laser therapies are often underutilized out of concern for post-treatment dyspigmentation.

Objectives: Cryogen spray cooling (CSC) is critical for protecting the epidermis during laser dermatologic procedures. The widely used cryogen, R134a, has a high global warming potential (GWP), motivating interest in environmentally favorable alternatives such as HFO-1234ze. This study evaluated whether HFO-1234ze provides epidermal protection comparable to R134a during laser exposure and investigated the mechanistic basis underlying any differences in cooling performance.

Methods: Laser-induced epidermal injury in conjunction with two cryogens was assessed in K14-SCF Mc1r^e/e mice with pharmacologically controllable interfollicular epidermal pigmentation. Laser treatment sites were assigned fluences relative to baseline skin lightness (L*) to span subthreshold to suprathreshold injury conditions, with cryogen assignment randomized. Hypopigmentation at Day 7 served as the primary injury endpoint and was scored independently by three blinded raters. Surface cooling induced by each cryogen was measured separately using thin-film thermocouples on a skin phantom, and subsurface temperature distributions were estimated using one-dimensional transient heat-transfer modeling.

Results: Mean hypopigmentation scores did not differ significantly between R134a- and HFO-1234ze-cooled sites across the full range of pigmentation and fluence studied (p = 0.46). Heat-map analysis and regression modeling confirmed that hypopigmentation increased with fluence and darker pigmentation but was independent of cryogen type. Surface temperature measurements using skin phantom revealed that R134a produced more aggressive transient cooling than HFO-1234ze, reaching approximately 10°C lower minimum temperatures. However, numerical modeling of skin cooling using heat flux inferred from phantom measurement showed that this surface advantage decayed rapidly with depth, resulting in ≤ 2°C-3°C differences within the viable epidermis.

Conclusions: Despite differences in surface cooling magnitude, R134a and HFO-1234ze provided equivalent epidermal protection under clinically relevant conditions. These findings support HFO-1234ze as an effective, lower-GWP alternative to R134a for CSC in laser dermatologic applications.

Background: Field cancerization is a major concern in photodamaged skin due to its risk of progression to squamous cell carcinoma. The 1927-nm thulium laser has emerged as a promising therapy, but its isolated effects on this condition remain underexplored.

Objective: To evaluate clinical and histopathological changes in field cancerization treated with the 1927-nm thulium laser.

Methods: It was a prospective, observational, and interventional clinical study. Twenty-three patients (age average of 61.3 years), phototype I-III, with facial photodamage and multiple actinic keratosis underwent 4 monthly sessions of thulium laser, followed by a 3-month evaluation. Outcomes included lesion counts and a photoaging scale at each session, along with comprehensive histological analysis of pre- and post-treatment biopsies from 20 patients.

Results: There was a significant reduction in AK count (p < 0.001) and photoaging parameters (p < 0.001). Histologically, we observed improvement in vertical extension of keratinocyte atypia (p = 0.046), increased dermal thickness (p = 0.012), and fibroplasia (p < 0.001). No severe adverse effects occurred.

Conclusion: The 1927-nm thulium laser is a safe, well-tolerated and has promising results as a field-directed therapy for actinic keratosis, promoting both clinical and histopathological improvement.

Objective: To construct a 10.6 μm laser-induced corneal injury model in C57BL/6J mice and observe the wound healing process.

Methods: Four groups of C57BL/6J mice corneas were irradiated with a 10.6 μm laser at dose of 3.0, 4.5, 7.5, and 10.5 J/cm². Corneal injury severity was assessed 1 day after exposure using slit lamp microscopy, optical coherence tomography, and histopathology to determine the optimal dose for constructing corneal injury model. Following this, the corneal wound healing was monitored with the same methods for 6 months.

Results: No corneal damage was observed at dose of 3.0 J/cm². At 4.5 J/cm², a white circular lesion appeared, accompanied by the loss of epithelium and endothelium. At 7.5 and 10.5 J/cm², full-thickness corneal damage was observed, with adhesion to the iris. Therefore, 4.5 J/cm² was selected for constructing the corneal injury model. After injury, the corneas swelled rapidly, reaching maximum at 1 day, and returned to normal by 14 days. From 0hours to 3 days, the corneas exhibited shedding and regeneration of epithelial and endothelial cells, as well as infiltration and regression of inflammatory cells. From 7 days to 6 months, the corneas gradually returned to normal, but some mice still showed stromal hyperplasia.

Conclusion: A moderate corneal injury model can be established in C57BL/6J mice using a 10.6 μm laser at dose of 4.5 J/cm². The acute phase of corneal injury primarily occurs within the first 3 days. While the corneas restore its original physiological structure, transparency may not fully return to normal by 6 months.

Objectives: Laser hair removal (LHR) is an essential gender-affirming procedure for transgender patients, yet limited data exist on its safety and tolerance in this population. This study evaluates treatment parameters, outcomes, and side effects of intense pulsed light (IPL) LHR in a large cohort of transgender patients.

Methods: A retrospective cohort study was conducted on 115 transgender patients treated at tertiary dermatology laser center in the United Kingdom between December 2020 and March 2024. The study included transgender patients, aged 18 and over, who had received at least one treatment of LHR. Patient demographics, laser settings, treatment outcomes, and adverse effects were extracted from electronic records.

Results: The average patient age was 34 years (20-73). Fitzpatrick skin types 2 (46%) and 3 (29%) were most common, with brown hair (67%) being the predominant hair color. Fourteen patients had previous electrolysis and 90 patients were on hormone therapy. All patients were treated with IPL device, with the most common wavelength being 695 nm (75%). The typical fluence used ranged from 19 to 21 J/cm², with 20 J/cm² (25%) being the most common. Visual analog scores (VAS) for pain averaged 5 during treatment, peaking at the third session (VAS 7). Thirty-five patients (30%) required additional test patches, with subsequent change in settings. Common expected side effects included redness (70%), perifollicular swelling (56%), and burning hair odor (53%), with no scarring or burns reported. Fifty-nine patients completed the treatment, requiring an average of eight treatments (4-13), and 52 patients remaining under follow-up.

Conclusion: This large retrospective study reports the safety and tolerance of IPL facial LHR as a gender-affirming procedure in a real-world transgender patient cohort, and highlights the common treatment parameters used in our population. The study emphasizes the need for personalized laser settings, close monitoring, and future research on quantitative efficacy and standardized treatment protocols to improve effectiveness and improve safety for transgender patients undergoing LHR.

Objectives: Laser therapy is popular for dermatological treatments due to its precision and effectiveness. Post-treatment, applying topical agents helps the skin recover and improves esthetic outcomes. This study aims to investigate the efficacy of collagen dressings in promoting the repair of ex vivo skin tissue following laser treatment, focusing on barrier repair and collagen regeneration.

Methods: This study utilized Q-switched lasers with wavelengths of 532 and 1064 nm to irradiate ex vivo skin tissue. Following laser treatment, collagen dressings were applied. Three types of dressings were evaluated: Type A (laboratory‑prepared Type I collagen formulation), Type B (a commercial dressing based on Type I collagen), and Type C (a commercial dressing incorporating recombinant Type III collagen). The effects of these dressings on skin barrier recovery were assessed by observing Nile Red penetration and measuring the expression levels of skin barrier-related proteins (pan-Keratin, Filaggrin, and Claudin-1). The collagen regeneration in the laser-treated skin tissue was evaluated using Masson staining, and by analyzing the expression of Collagen I (COL I).

Results: Collagen-based dressings facilitated the recovery of the skin barrier, with Type A and Type B dressings showing effectiveness in early-stage barrier repair. During 120-h culture, collagen dressings inhibited the transient upregulation of MMP‑1 while enhancing COL I expression, particularly with the Type C dressing.

Conclusion: The results indicate that collagen dressings provide therapeutic benefits for post-laser skin recovery. These findings highlight the potential of collagen dressings in enhancing the synergistic effects of laser treatments and skin care, suggesting paths for improved clinical practices.

Background: Postinflammatory hyperpigmentation (PIH) is the most common adverse effect following laser treatments, yet the relative efficacy of proposed prophylactic measures remains uncertain.

Objectives: To compare the effectiveness of available interventions for preventing laser-induced PIH in randomized controlled trials (RCTs).

Methods: PubMed, Embase, Scopus, Cochrane Library, and ClinicalTrials.gov were searched through February 2025. RCTs reporting PIH incidence after laser or other energy-based treatments were eligible. A random-effects network meta-analysis (NMA) combined direct and indirect evidence; treatments were ranked by surface under the cumulative ranking curve (SUCRA).

Results: Fourteen RCTs were included in the systematic review, with 11 included in the NMA. Intradermal tranexamic acid (TXA), topical corticosteroids, topical vasoconstrictors, oral TXA, and epidermal cooling were significantly more effective in reducing PIH incidence compared with sunscreen monotherapy, with intradermal TXA demonstrating the highest efficacy (RR: 0.02, 95% CI: 0.00-0.53). Whitening agents and epidermal growth factor formulations did not show significant benefit over sunscreen, while sunscreen monotherapy was ineffective compared with placebo. Reported adverse events were generally mild, although intradermal TXA was associated with injection site discomfort and bruising.

Conclusion: This systematic review and NMA indicate that topical corticosteroids and intradermal TXA may offer greater protection against laser-induced PIH than sunscreen monotherapy. Preventive strategies should be incorporated into laser treatment planning, particularly for patients with higher risk of hyperpigmentation. Overall, the findings support an evidence-based and individualized approach to PIH prevention. Interpretation should remain cautious due to the limited number and modest sample sizes of included trials.