Study on Phenol-Formaldehyde Resin-Montmorillonite Impregnation and Compression Modification of Chinese Fir.

In this study, a phenol-formaldehyde resin-montmorillonite intercalation composite solution was used as a modifier to treat Chinese fir via impregnation and compression. The basic characteristics and wettability of the PF (phenol-formaldehyde)-montmorillonite impregnation solution were analyzed. The effects of the solid content of PF, the quantity of montmorillonite, and the impregnation time on the impregnation weight gain of Chinese fir were studied through orthogonal experiments. The results showed that when the amount of montmorillonite was 1%, the wettability of the PF-montmorillonite impregnation solution performed the best, the curing time was short, and the curing strength was high. The optimal impregnation process consists of a PF solid content of 25%, an impregnation time of 120 min, and a montmorillonite ratio of 1%. Under these conditions, the modified Chinese fir was prepared via hot pressing. The effects of the addition of montmorillonite and different levels of compressibility on the physical and mechanical properties of modified wood were studied. The physical and mechanical properties were found to be better when the compression ratio was 33%: the density increased from 0.33 g/cm3 to 0.58 g/cm3; the surface hardness increased from 33.6 HD to 70.9 HD; the static bending strength increased from 60.4 MPa to 98.7 MPa; and the elastic modulus increased from 6 390 MPa to 11 498 MPa. After 30 days of release, the compression rebound rate was 3.97%. Meanwhile, the micromorphology and heat resistance of the impregnated compressed Chinese fir showed that the PF-montmorillonite impregnation solution entered into the cell cavity and intercellular space of the Chinese fir and formed a good composite, thus improving the water resistance, heat resistance, and physical and mechanical properties.

Comparative Study of the Morphological Characteristics of Perforators of the Transverse and Descending Branches of the Lateral Circumflex Femoral Artery in Anterolateral Thigh Flap Surgery.

BACKGROUND: The anterolateral thigh flap (ALTF) is a kind of lateral thigh flap that uses branches of the lateral circumflex femoral artery (LCFA) as the vessel pedicle and is widely used in plastic surgery. During classic ALTF surgery, some perforators from the descending branch of the lateral circumflex femoral artery (LCFA-db) are hard to harvest due to their anatomical variants and individual differences; thus, it is necessary to design an appropriate alternative surgical plan. The transverse branch of the LCFA (LCFA-tb) has unique advantages and can be a potential complement to ALTF vascular pedicle selection. The aim of this study was to compare the difference in morphology between LCFA-db and LCFA-tb, and to verify the feasibility and clinical effect of ALTF with LCFA-tb as the source artery. METHODS: The morphological and clinical data of patients who underwent wound repair of the extremities with the ALTF pedicled with the LCFA-tb and LCFA-db were retrospectively analyzed. This study consisted of the clinical data of 62 patients who accepted an ALTF pedicled with LCFA-tb, and 45 patients accepted an ALTF pedicled with LCFA-db. RESULTS: A total of 68 cutaneous perforators originating from the LCFA-tb were found in the surgical field, of which 35 perforators were direct cutaneous perforators (51.5%), 28 perforators were septocutaneous perforators (41.2%), and 5 perforators were musculocutaneous perforators (7.3%). Seventy-four cutaneous perforators were found in the LCFA-db group. The proportions of septocutaneous perforators and musculocutaneous perforators were 23% and 77%, respectively, and the number of direct cutaneous perforators was 0. The harvest time of flaps pedicled with LCFA-tb was remarkably shortened. Regarding prognosis, there were no significant differences between the curative effects of the 2 types of flaps. CONCLUSIONS: This study verified that most LCFA-tb perforators are direct cutaneous perforators and that the piercing-in positions of LCFA-tb perforators on superficial fascia were higher than those of LCFA-db perforators. Furthermore, the ALTF pedicled with LCFA-tb can provide satisfactory soft tissue reconstruction and can be used as a useful supplement to the traditional flap design.

Is the oblique branch of the lateral circumflex femoral artery a common variant?

The oblique branch of the lateral circumflex femoral artery, a short branch of the deep femoral artery, is highly prevalent (32-46%) and is usually considered a normal variant, although this is still controversial. This study aimed to evaluate whether the oblique branch of the lateral circumflex femoral artery is a variant. We reviewed medical record data of patients with skin and soft tissue defects of the extremities who underwent flap repair using free anterolateral thigh (ALT) flaps at our hospital in 2019. The anatomical characteristics of the flaps were examined intraoperatively by high-frequency color Doppler ultrasound. A total of 153 ALT flaps from 146 patients were included. Among the branches, 232 (73.7%) were oblique branches, and 83 (26.4%) were descending branches. Of the 232 oblique branches, 141 (60.8%) were from septocutaneous branches, and the other 83 (39.2%) were from musculocutaneous branches. In addition, 20 (24.1%) descending branches were from septocutaneous branches, and the other 63 (75.9%) were from musculocutaneous branches. Analyzing the prevalence of the oblique branch in septocutaneous branches, more than half of the patients had oblique branches rather than descending branches. The high proportion of oblique branches from septocutaneous branches (median: 100 (0-100) vs. 0 (0-50), p = 0.002) supports the understanding that the oblique branch is a normal anatomical element rather than a variant. The main type was the intramuscular branches, which required significantly less time for flap harvesting. The oblique branch may be the preferred vascular pedicle for free ALT flaps.

[Clinical application of anterolateral thigh perforator flap pedicled with oblique branch in intramuscular of lateral circumflex femoral artery].

Objective: To explore the characteristics and clinical application of the anterolateral thigh flap pedicled with the oblique branch in the intramuscular of lateral circumflex femoral artery. Methods: The clinical data of 25 patients with skin and soft tissue defects of extremities admitted between December 2020 and April 2021 were retrospectively analyzed, including 16 males and 9 females, aged 14-75 years, with the median age of 43 years. The defect site included 13 cases of hand, 2 cases of forearm, 2 cases of calf, and 8 cases of foot and ankle. The wound area ranged from 6 cm×4 cm to 35 cm×22 cm. Twenty-four patients with trauma were admitted to hospital immediately after injury, and 1 patient with diabetic foot infection was transferred to the hospital after ineffective treatment in other hospital. Flap surgery was performed from 0 to 56 days (median, 22 days) after admission. A total of 26 thigh flaps were harvested in 25 patients, with unilateral flaps in size of 7 cm×5 cm to 40 cm×10 cm. The type, caliber, and location of the perforating branch were recorded during the operation, and the anatomical characteristics of the oblique branch of the intramuscular trunk were mainly observed. The flap harvesting time was recorded; the flap survival and wound healing time were observed; at last follow-up, XIAO Feipeng et al. flap comprehensive efficacy evaluation table was used to evaluate the effectiveness of flap repair from three aspects of donor site, recipient site, and subjective satisfaction of doctors and patients. Results: After the oblique branch in intramuscular of lateral circumflex femoral artery was sent out, it ran 2-3 cm obliquely laterally and inferiorly in the intermuscular septum and then entered the vastus lateralis muscle, and sent out perforating branches to nourish the skin. A total of 61 perforating branches were marked in 26 thighs of 25 patients before operation, and 70 perforating branches were found during operation, including 9 transverse branches, 29 descending branches, and 32 oblique branches, all of the oblique branches were musculocutaneous perforators. All 25 patients were followed up 6-10 months, with an average of 8 months. The time of unilateral thigh flap harvesting ranged from 13 to 90 minutes, with an average of 48 minutes. One patient with diabetes developed disturbance of blood supply and complete necrosis of the flap at 1 month after operation, and then the flap was repaired with skin graft; 1 case developed arterial crisis after operation, which survived after timely exploration; and the rest of the flaps survived smoothly. The wound healing time of the recipient site ranged from 10 to 44 days, with an average of 19 days, and the donor site of the thigh healed by first intention. At last follow-up, the color and texture of the flap was good and the sensation recovered to S 1-S 2. Only linear scar was left in the donor site, no scar contracture, pain, and other discomfort occurred, and no other serious complications occurred. Evaluated by flap comprehensive efficacy evaluation table, the score was 74-93, with an average of 88, of which 10 cases were excellent, 13 cases were good, and 2 cases were fair, with an excellent and good rate of 92%. Conclusion: The intramuscular trunk oblique branch is not uncommon, and its trunk course and perforators distribution are regular. To improve the understanding of this type of oblique branch and adopt appropriate methods during operation can improve the success rate of skin flap extraction.