Hyun Ho Han

Objective: Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by epidermal barrier disruption and immune dysregulation. Live-MB2 and CX-2 were used in an ex vivo human skin AD-like model, which provides a biologically relevant platform for assessing cosmetic ingredients targeting AD-like features. Methods: An AD-like condition was induced in ex vivo human skin explants by repeated tape stripping followed by 2,4-dinitrochlorobenzene stimulation. Skin tissues were treated with Live-MB2 or CX-2 via topical or dermal exposure. Epidermal thickness, IgE, and filaggrin levels were evaluated using hematoxylin and eosin, immunofluorescence, and Enzyme-Linked Immunosorbent Assay analyses. Results: Topical application of Live-MB2 and CX-2 significantly reduced epidermal thickness compared with AD-induced controls. IgE levels were significantly reduced, while filaggrin expression indicated a marked increase, indicating barrier recovery. No treatment-related tissue damage was observed. Conclusion: Live-MB2 and CX-2 showed favorable effects on inflammatory and barrier-related parameters in an ex vivo human skin AD-like model, supporting their potential application as cosmetic ingredients for sensitive and atopic-prone skin.

Conventional detergent-based decellularization can disrupt the extracellular matrix (ECM) structure and denature proteins. Supercritical carbon dioxide (scCO2) processing offers a simplified manufacturing process (<2 hours), minimal protein denaturation, and excellent ECM preservation. This study aimed to evaluate the clinical outcomes of scCO2 processing acellular dermal matrix (ADM) compared with conventional detergent-processed ADM. This prospective observational study enrolled patients undergoing immediate implant-based breast reconstruction with scCO2-processed ADM (n = 50) and compared outcomes with a retrospective cohort receiving conventional detergent-processed human ADM (n = 50). Patient demographics, comorbidities, and treatment variables were collected. Postoperative complications and BREAST-Q–assessed patient-reported outcomes were analyzed. The groups were comparable in age (45.0 ± 10.4 years vs. 46.8 ± 9.4 years, p = 0.362), body mass index (median: 21.5 kg/m2 vs. 22.7 kg/m2, p = 0.558), comorbidities, and oncologic characteristics. Rates of skin necrosis (2% vs. 0%), nipple–areolar complex necrosis (2% vs. 2%), hematoma (4% vs. 4%), seroma (6% vs. 0%), infection (6% vs. 0%), capsular contracture (8% vs. 12%), implant failure (0% vs. 0%), implant change (2% vs. 2%), and reoperation (2% vs. 2%) did not differ significantly between groups. BREAST-Q questionnaires revealed no significant differences in patient-reported outcomes. scCO2-processed ADM demonstrated safety and patient-reported outcomes equivalent to established detergent-based ADMs. Given its eco-friendly, protein-preserving manufacturing process, scCO2-processed ADM represents a safe and effective alternative for implant-based breast reconstruction. Long-term follow-up studies are warranted.

Peripheral nerve repair remains a major clinical challenge, and novel strategies such as conduit-assisted repair have been developed to improve outcomes. In this study, we fabricated a 3D-printed nerve guidance conduit (NGC) composed of polycaprolactone (PCL), a biocompatible and biodegradable polymer, combined with acellular dermal matrix (ADM) derived from porcine dermis, in order to create a multilayered PCL–ADM NGC with both favorable mechanical properties and biological activity. Twenty rabbits were divided into four groups: a negative control group, a silicone tube repair group, an autologous nerve graft group, and a group treated with the 3D-printed PCL–ADM NGCs. Sciatic nerve regeneration was assessed at 4 and 12 weeks postoperatively using electrophysiological measurements, histological staining, and electron microscopy. The PCL–ADM NGC demonstrated comparable axonal regeneration and functional recovery to autologous grafting, and it significantly outperformed silicone tubes in terms of axonal count and maximal electrophysiological response. Histological and ultrastructural analyses further confirmed that the PCL–ADM NGC facilitated organized regeneration with dense myelinated axons and reduced degenerative changes. The fabricated NGCs exhibited excellent flexibility without compromising lumen diameter, which is critical for adapting to the physiological environment of peripheral nerves. These findings indicate that combining synthetic polymers with biologically derived matrices can enhance the regenerative microenvironment and overcome limitations of traditional synthetic conduits. In conclusion, the 3D-printed PCL–ADM NGC represents a promising alternative to both silicone tube repair and autologous nerve grafting by providing structural support and bioactivity while reducing the need for donor nerve harvesting. Further studies in larger animal models and longer follow-up periods will be required to confirm long-term efficacy and support clinical translation of this technology.

Microsurgical breast reconstruction offers superior outcomes after mastectomy, but vascular microanastomosis remains technically demanding. Venous couplers are widely adopted, whereas the use of arterial couplers remains controversial. This study aimed to establish an algorithmic approach for arterial coupler use and compare outcomes with hand-sewn sutures. A retrospective review was performed on 105 patients undergoing deep inferior epigastric perforator flap breast reconstruction by a single surgeon. Patients were divided into an arterial coupler group (n = 62) and a hand-sewn suture group (n = 43). An intraoperative algorithm guided coupler use, requiring the absence of atherosclerosis, intact intima, and adequate vessel laxity. Demographics, operative details, microanastomosis time, and postoperative outcomes were analyzed. Patients in the coupler group were younger (47.6 ± 8.6 vs. 53.0 ± 7.9 years, p = 0.001) and underwent more robot-assisted procedures (16.1% vs. 2.3%, p = 0.025). Microanastomosis time was significantly shorter with couplers (19.6 ± 8.9 vs. 26.1 ± 6.5 minutes, p < 0.01). Flap survival was comparable between groups (96.8% vs. 100%, p = 0.512). Complication rates, including arterial/venous insufficiency, hematoma, and infection, showed no significant differences. Two coupler failures occurred: One venous congestion and one late thrombosis, both attributed to multifactorial causes rather than device failure. Arterial couplers, when used under strict algorithmic selection criteria, provide reliable outcomes comparable to hand-sewn sutures while significantly reducing operative time. This approach enhances efficiency in microsurgical breast reconstruction and may guide future standardized practice.

Indocyanine green angiography (ICGA) is widely used to evaluate flap perfusion in reconstructive surgery, but the optimal timing for assessment may differ by flap type. This study compared the perfusion dynamics of perforator and random pattern flaps in a rat model using ICGA.ICGA dynamics were compared between perforator and random flaps in a rat model. Sixteen Sprague–Dawley rats (275–300 g) were randomly assigned to either a perforator or a random flap group. A 0.25-mg dose of indocyanine green (ICG) was administered via the femoral vein, and fluorescence images were acquired at predefined intervals over 4 minutes. Hypoperfusion was defined as fluorescence intensity below 30% of the peak value. Necrosis was assessed on postoperative day 7. Statistical analyses included the Mann–Whitney U and log-rank tests with Expectation-Maximization Iterative Convex Minorant (EMICM) modeling.In the perforator flap group, the final area of necrosis corresponded to the ICGA-defined perfusion boundary observed between 10 and 50 seconds postinjection. In contrast, necrosis in the random flap group aligned with the ICGA-defined perfusion boundary captured between 30 and 150 seconds. The most accurate time points for necrosis prediction were 50 seconds for perforator flaps and 150 seconds for random flaps, both demonstrating statistical significance (p = 0.0028).ICGA timing requirements differ between flap types. Implementing flap-specific assessment windows may enhance intraoperative interpretation and reduce false-positive findings. These findings support the development of flap-specific ICGA protocols to improve intraoperative decision-making in reconstructive surgery.

Background: Two types of robotic systems are mainly used in implant-based robot-assisted breast reconstruction (RBR): the single-site approach using the da Vinci Xi system (Xi-RBR), and SP system (SP-RBR). In this study, we aimed to compare Xi-RBR and SP-RBR in prosthetic breast reconstruction. Methods: A total of 24 patients (27 breasts) and 25 patients (25 breasts) underwent implant-based breast reconstruction from July 2019 to October 2021 with da Vinci Xi and SP, respectively, by a single surgeon. Data were collected through a retrospective chart review regarding patient demographics, surgical factors, and complications. Results: There were no significant differences in demographics overall. The average operation time of the Xi-RBR group was 85.28 minutes, which was significantly longer than that (72.33 min) of the Xi-RBR group (P = 0.0168). In addition, the size of the acellular dermal matrix used in the SP-RBR group was significantly larger than that used in the Xi-RBR group (P = 0.0041). However, there were no significant differences in surgical complications between the 2 groups. Conclusions: The da Vinci Xi system is convenient to use, is easy to operate, and has a less steep learning curve. However, the da Vinci SP system, although more difficult to operate, is more appropriate for breast surgery. As there are no significant differences in the surgical outcomes between the systems, we recommend using the da Vinci SP for implant-based breast reconstruction.

Although autologous breast reconstruction using the deep inferior epigastric artery perforator (DIEP) flap is a standard procedure, flap perfusion-associated complications remain a concern. This study aimed to investigate the correlation between blood flow information obtained through color Doppler ultrasonography (CDU) and flap perfusion assessed by indocyanine green (ICG) angiography. This prospective study included 30 female patients who underwent DIEP flap breast reconstruction between August 2023 and June 2024. Preoperative flow parameters, including arterial peak velocity, arterial volume flow, and venous peak velocity, were measured using CDU. Flap perfusion was evaluated using ICG angiography. The study demonstrated a positive correlation between venous flow and overall flap blood flow. Arterial peak velocity (r = 0.368, p = 0.046), arterial volume flow (r = 0.455, p = 0.011), and venous peak velocity (r = 0.399, p = 0.029) all showed significant associations with ICG-stained area percentages. These findings suggest that venous flow data can provide valuable information for predicting flap viability. This study demonstrates a significant correlation between flow information obtained through CDU and flap perfusion assessed via ICG angiography in patients undergoing DIEP flap breast reconstruction. Both arterial and venous flow data were shown to be crucial for predicting flap viability, with venous flow exhibiting a notable positive correlation with flap blood flow.