[Microsurgical thinned anterolateral thigh perforator flap to repair soft tissue defects of foot and ankle].

OBJECTIVE: To explore method and clinical effect of microsurgical thinned anterolateral thigh perforator flap to repair soft tissue defects of foot and ankle. METHODS: From March 2017 to January 2022, totally 20 patients with soft tissue defects of ankle joint were treated with micro-thinning anterolateral perforator flap for free transplantation, included 13 males and 7 females, aged from 22 to 58 years old with an average of (36.45±12.36) years old. The size of flap ranged from 8.0 cm×5.0 cm to 20.0 cm×12.0 cm. Before operation, perforating vessels on the anterolateral thigh region were detected and marked with a portable Doppler detector. For the defect width less than 8 cm, 11 patients were repaired with a single flap. For the defect width more than 8 cm, the wound could not be sutured directly, and the lobulated flap technique was used in 9 patients, the width was converted to length, and the donor site was closed directly. Under the microscope, all flaps were thinened in a stepwise manner from the center of the pedicle to the periphery. After operation, survival of the flap, the shape, texture, sensory function recovery were observes, and recovery of foot function was evaluated by Maryland foot function evaluation standard. RESULTS: All 20 patients with microsurgical thinned anterolateral thigh perforator flaps were survived. Venous crisis occurred in 1 patient due to subcutaneous hematoma, after removal of the hematoma, the crisis was relieved and the flap survived successfully. The wounds in the donor and recipient sites healed well, and only linear scars left in the donor sites. Twenty patients were followed up for 3 to 26 months after operation, good shape of flaps without bloated, and good texture. The two-point discrimination of free flaps ranged from 9.0 to 16.0 mm, and the protective sensation was restored. The ankle flexion and extension function recovered well and patients could walk normally. According to Maryland foot function evaluation standard, 8 patients got excellent result, 10 patients good and 2 middle. CONCLUSION: Microsurgical thinned anterolateral thigh perforator flap is an ideal method to repair soft tissue defects in functional area of foot and ankle, with good appearance and texture of the flap, no need for re-plastic surgery, reduced hospitalization costs, and less donor site damage.

Hierarchically porous SiO2/polyurethane foam composites towards excellent thermal insulating, flame-retardant and smoke-suppressant performances.

Polyurethane foam (PUF) is widely used in building insulation field but highly flammable. In an effort to develop an efficient way to reduce flammability and smoke release of PUF without sacrificing its inherent merits, a novel strategy has been proposed to decorate silica aerogels onto the surface of PUF to fabricate hierarchically porous SiO2/PUF composites. Due to the unique hierarchically porous structure, the resultant composites showed superior thermal insulation with a lower thermal conductivity of 0.0282 W/(m K). The introduction of silica aerogels also effectively improved the compressive strength, almost 220% of that of neat PUF. Notably, the SiO2/PUF composites were rendered self-extinguishing in vertical burning tests and had a high limiting oxygen index (LOI) value of 32.5%. Cone calorimetry (CC) tests revealed that the peak heat release rate (PHRR) and peak smoke production release (PSPR) of the SiO2/PUF composites were reduced by 40.4% and 45.6%, respectively. Particularly, the specific optical density (Ds) of the composites displayed as 55.7% reduction in the smoke density chamber tests, showing excellent smoke-suppression. The mechanism analysis suggested that a compact silica-rich hybrid barrier formed, preventing thermal degradation products and energy transfer during combustion. These results indicate SiO2/PUF composites have enormous potential as building insulation materials.

Green Approach to Improving the Strength and Flame Retardancy of Poly(vinyl alcohol)/Clay Aerogels: Incorporating Biobased Gelatin.

Biobased gelatins were used to improve the compressive properties and flammability of poly(vinyl alcohol)/montmorillonite (PVA/MMT) aerogels, fabricated using a simple and environmentally friendly freeze-drying method. Because of the excellent compatibility and strong interfacial adhesion between PVA and gelatin, the compressive moduli of aerogels were enhanced dramatically with the incorporation of gelatin. PVA/MMT/porcine-gelatin aerogels exhibit compressive modulus values as much as 12.4 MPa, nearly 300% that of the control PVA/MMT aerogel. The microstructure of the PVA/MMT/gelatin aerogels shows a three-dimensional co-continuous network. Combustion testing demonstrated that with the addition of gelatin, the self-extinguishing time of the aerogel was cut by half and the limiting-oxygen-index values increased to 28.5%. The peak heat-release rate, obtained from cone calorimetry, also decreased with the incorporation of gelatin. Thermogravimetric analysis demonstrated that the gelatins slowed the sharp decomposition of the PVA matrix polymer and increased the thermal stability of the aerogels at the major decomposition stage of the composite aerogels. These results indicate that as a green, biobased material, gelatin could simultaneously improve the mechanical properties and the properties of flame retardancy.