Bioprinted dermis with human adipose tissue-derived microvascular fragments promotes wound healing.

Tissue-engineered skin is an effective material for treating large skin defects in a clinical setting. However, its use is limited owing to vascular complications. Human adipose tissue-derived microvascular fragments (HaMVFs) are vascularized units that form vascular networks by rapid reassembly. In this study, we designed a vascularized bionic skin tissue using a three-dimensional (3D) bioprinter of HaMVFs and human fibroblasts encapsulated in a hybrid hydrogel composed of GelMA, HAMA, and fibrinogen. Tissues incorporating HaMVFs showed good in vitro vascularization and mechanical properties after UV crosslinking and thrombin exposure. Thus, the tissue could be sutured appropriately to the wound. In vivo, the vascularized 3D bioprinted skin promoted epidermal regeneration, collagen maturation in the dermal tissue, and vascularization of the skin tissue to accelerate wound healing. Overall, vascularized 3D bioprinted skin with HaMVFs is an effective material for treating skin defects and may be clinically applicable to reduce the necrosis rate of skin grafts.

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.

Angiopoietin-like 4 promotes epidermal stem cell proliferation and migration and contributes to cutaneous wound re-epithelialization.

Proliferation and migration of epidermal stem cells (EpSCs) are essential for epithelialization during skin wound healing. Angiopoietin-like 4 (ANGPTL4) has been reported to play an important role in wound healing, but the mechanisms involved are not fully understood. Here, we investigate the contribution of ANGPTL4 to full-thickness wound re-epithelialization and the underlying mechanisms using Angptl4-knockout mice. Immunohistochemical staining reveals that ANGPTL4 is significantly upregulated in the basal layer cells of the epidermis around the wound during cutaneous wound healing. ANGPTL4 deficiency impairs wound healing. H&E staining shows that ANGPTL4 deficiency significantly reduces the thickness, length and area of the regenerated epidermis postwounding. Immunohistochemical staining for markers of EpSCs (α6 integrin and ß1 integrin) and cell proliferation (PCNA) shows that the number and proliferation of EpSCs in the basal layer of the epidermis are reduced in ANGPTL4-deficient mice. In vitro studies show that ANGPTL4 deficiency impedes EpSC proliferation, causes cell cycle arrest at the G1 phase and reduces the expressions of cyclins D1 and A2, which can be reversed by ANGPTL4 overexpression. ANGPTL4 deletion suppresses EpSC migration, which is also rescued by ANGPTL4 overexpression. Overexpression of ANGPTL4 in EpSCs accelerates cell proliferation and migration. Collectively, our results indicate that ANGPTL4 promotes EpSC proliferation by upregulating cyclins D1 and A2 expressions and accelerating the cell cycle transition from G1 to S phase and that ANGPTL4 promotes skin wound re-epithelialization by stimulating EpSC proliferation and migration. Our study reveals a novel mechanism underlying EpSC activation and re-epithelialization during cutaneous wound healing.

Repair of Compound Dorsal Defects of the Digits Using a Free Antegrade Palmaris Longus Tendocutaneous Venous Flap.

PURPOSE: To investigate the clinical effect of repairing small dorsal digit compound tissue defects using a free palmaris longus tendocutaneous flap nourished by venous blood. METHODS: In a retrospective analysis of patients treated between March 2010 and October 2017, 18 patients were identified as having small compound tissue defects, which were repaired using a free palmaris longus tendocutaneous flap nourished by venous blood. The average age of the patients, including 15 male and 3 female patients, was 34 years (range, 22-55 years). The mean wound size was 6 cm2 (range, 2.0 × 1.5 to 3.5 × 2.0 cm2). All the patients had dorsal defects. The average length of extensor tendon defect was 2.0 cm (range, 1.0-3.0 cm). The mean area of the flap was 7 cm2 (range, 2.5 × 2.0 to 4.0 × 3.5 cm2). The donor sites were primarily closed. RESULTS: All 18 flaps survived. A vascular crisis due to a venospasm occurred within 48 hours in 3 flaps, but ultimately, all the flaps survived. The patients were followed-up for a mean period of 10 months (range, 3-15 months). All the patients returned to their previous work after 10-12 weeks. No pain or scar contracture was reported in either the recipient or donor site. CONCLUSIONS: The free antegrade palmaris longus tendocutaneous venous flap enabled the repair of compound tissue defects of the dorsal digit, resulting in acceptable aesthetics, repaired tendon defects, and wound coverage. This surgical method is an option for the reconstruction of small compound defects of digits with extensor defects. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The modified second toe flap technique based on the dorsal digital artery of the toe in finger pulp reconstruction.

BACKGROUND: The second toe flap is a widely used innervated neurovascular flap for repairing finger pulp defects. It mainly carries the proper plantar digital artery and nerve. But the donor site morbidity and arterial injury are common. The report retrospectively evaluated the clinical outcomes of the second toe free medial flap based on dorsal digital artery of the toe to investigate the esthetics and function in the treatment of soft tissue defects of fingertip pulp. METHODS: From March 2019 to December 2020, 12 patients with finger pulp defects (seven acute crush, three cut, and two burn) undergoing the modified second toe flap were chosen for retrospective review. The average patient age was 38.6 (range: 23-52) years. The mean defect size was 2.1 × 1.6 (range: 1.5 × 1.3-2.6 × 1.9) cm. The defects did not extend beyond the distal interphalangeal joint and the phalanges were not damaged in all cases. The average follow-up was 9.5 (range: 6-16) months. Demographic information, flap data, and perioperative characteristics were collected. RESULTS: The mean size of the modified flap was 2.3 × 1.8 (range: 1.7 × 1.5-2.7 × 2.0) cm and mean diameter of artery was 0.61 (range: 0.45-0.85) mm. The mean flap harvested time and operation time were 22.6 (range: 16-27) minutes and 133.7 (range: 101-164) minutes. A flap was ischemic after first day postoperatively and later it improved by releasing the sutures. All flaps were survival without necrosis. One patient was not satisfied with the appearance of the finger pulp because of scar hyperplasia. The other 11 patients were satisfied with the appearance and function of the injured digit after 6 months postoperatively. CONCLUSION: The modified second toe flap technique based on the dorsal digital artery of the toe is a feasible choice to reconstruct the sensation and appearance of the injured fingertip with current microsurgical techniques.

Reconstruction of the central slip insertion of the extensor tendon with the partial slip of the flexor digitorum superficialis tendon.

INTRODUCTION: To introduce the surgical approach and clinical effect of transferring the partial slips of the flexor digitorum superficialis (FDS) tendon to reconstruct the insertion of the central slip of the extensor tendon (CSET) through an established bone tunnel (BT). MATERIALS AND METHODS: From April 2019 to March 2021, nine patients (six males and three females) with the CSET insertion rupture or defect were admitted to the institution and the CSET insertion was reconstructed with partial tendon slips on both sides of the FDS. The active range of motion of the interphalangeal joint of the affected finger was measured by a goniometer, the degree of pain was evaluated by visual analogue scale (VAS), and the grip strength of the affected limb was measured by an electronic hand dynamometer. RESULTS: The average postoperative follow-up was 12 months. No complications occurred. At the last follow-up, six of the patients were very satisfied and three were satisfied with their recovery. CONCLUSION: The reconstruction of the CSET insertion by transferring the partial tendon slips of the FDS seem to be safe and feasible with minimal invasion to the donor tendon. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Bioprinting small-diameter vascular vessel with endothelium and smooth muscle by the approach of two-step crosslinking process.

Three-dimensional bioprinting shows great potential for autologous vascular grafts due to its simplicity, accuracy, and flexibility. The 6-mm-diameter vascular grafts are used in clinic. However, producing small-diameter vascular grafts are still an enormous challenge. Normally, sacrificial hydrogels are used as temporary lumen support to mold tubular structure which will affect the stability of the fabricated structure. In this study, we have developed a new bioprinting approach to fabricating small-diameter vessel using two-step crosslinking process. The » lumen wall of bioprinted gelatin mechacrylate (GelMA) flat structure was exposed to ultraviolet (UV) light briefly for gaining certain strength, while ¾ lumen wall showed as concave structure which remained uncrosslinked. Precrosslinked flat structure was merged towards the uncrosslinked concave structure. Two individual structures were combined tightly into an intact tubular structure after receiving more UV exposure time. Complicated tubular structures were constructed by these method. Notably, the GelMA-based bioink loaded with smooth muscle cells are bioprinted to form the outer layer of the tubular structure and human umbilical vein endothelial cells were seeded onto the inner surface of the tubular structure. A bionic vascular vessel with dual layers was fabricated successfully, and kept good viability and functionality. This study may provide a novel idea for fabricating biomimetic vascular network or other more complicated organs.

Sinus Tarsi Approach With Percutaneous Screw Fixation for Intra-Articular Calcaneal Fractures.

The aim of this study was to evaluate the outcomes of surgical treatment of intra-articular calcaneal fractures by using the sinus tarsi approach combined with percutaneous medial reduction by leverage technique and percutaneous screw fixation. We assessed the outcomes of 29 patients treated using sinus tarsi approach with percutaneous screw fixation. All patients were evaluated both clinically and radiologically. The Böhler and Gissane angle were evaluated postoperatively using radiographs. During the median follow-up period of 27.0 ± 10.3 months, no cases with failure to reduce or displace hardware were detected. All cases achieved the restoration of a normal Böhler and Gissane angle. The median preoperative Böhler angle was 12.3° ± 2.5° while postoperatively it was 30.5° ± 5.7° (p < .01). The median preoperative Gissane angle was 98.1° ± 7.5°, which was 125.9° ± 3.6° postoperatively (p < .01). At the last follow-up, the median American Orthopedic Foot and Ankle Society hindfoot score was 87.7 ± 5.9, and the median Maryland foot score was 88.6 ± 5.9. Our technique for intra-articular calcaneal fractures can effectively correct calcaneal tuberosity outward displacement, medial wall overlapping, and the hindfoot varus deformity with less soft tissue damage. This technique is a good alternative for the treatment of calcaneal fractures, resulting in minimal soft tissue damage, few wound complications, and excellent radiological and clinical outcomes.

Mechano-regulation of vascular network formation without branches in 3D bioprinted cell-laden hydrogel constructs.

Restoration of a wound is a common surgical procedure in clinic. Currently, the skin required for clinical use is taken from the patient's own body. However, it can be difficult to obtain enough skin sources for large-sized wounds and thus surgeons have started using commercial skin substitutes. The current commercial skin, which includes epidermis substitute, dermis substitute, and bilateral skin substitute, has been popularized in clinic. However, the application is limited by the occurrence of ischemia necrosis after transplantation. Recent studies suggest the use of pre-vascularized skin substitutes for wound healing is a promising area in the research field of skin tissue engineering. Pre-vascularization can be induced by changes in cultivation periods, exertion of mechanical stimuli, or coculture with endothelial cells and various factors. However, few methods could control the formation of vascular branches in engineering tissue in a self-assembly way. In this study, we use three-dimensional (3D) printing technology to confirm that a mechanical force can control the growth of blood vessels in the direction of mechanical stimulation with no branches, and that Yes-associated protein activity is involved in the regulatory progress. In vivo experiments verified that the blood vessels successfully function for blood circulation, and maintain the same direction. Results provide a theoretical basis for products of pre-vascularized skin tissues and other organs created by 3D bioprinting.

Articular calcaneal fractures: open or minimally invasive surgery, when the medial wall reduction is obtained percutaneously from the lateral side.

PURPOSE: The purpose of this study was to compare the clinical outcomes of intra-articular calcaneal fractures with medial column displacement treated with different surgical techniques, namely extensile lateral approach (ELA) or sinus tarsi approach (STA), combined with percutaneous medial reduction. METHODS: Ninety-six patients with intra-articular calcaneal fractures who were subjected to ELA or STA (45 in STA group and 51 in ELA group) were retrospectively assessed. Reduction of the posterior facet, calcaneal body, Böhler's angle, and Gissane's angle were evaluated. Clinical outcomes were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analog scale (VAS). The complications, time to surgery, operative time, and blood loss were also assessed. RESULTS: Incidence of wound complications, post-operative blood drainage, and time to the operation were significantly different between the two groups. There was no significant difference in the recovery of calcaneal anatomy and articular surface between the two groups. Similarly, no difference was detected in Böhler's and Gissane's angles between ELA and STA groups (P > 0.05). Finally, there was no difference in AOFAS and VAS scores between the two groups at the final follow-up (P > 0.05). CONCLUSION: STA resulted in favourable radiological and clinical results with fewer wound complications and a shorter waiting time when compared to ELA. The percutaneous medial reduction technique is effective in reducing medial column displacement.

D-allose alleviates ischemia/reperfusion (I/R) injury in skin flap via MKP-1.

BACKGROUND: D-allose was promising in the protection of ischemia/reperfusion (I/R) injury. We intended to investigate the function of D-allose in skin flap of rat followed by the injury of I/R and whether ERK signal pathway was involved in. METHODS: The back flap of Wistar rats was picked up with a vascular bundle of the lateral chest wall. I/R model was made by the venous clamp for 6 h. Rats received D-allose and PD-98059, the inhibitor of ERK1/2, 30 min before modeling. Morphology of tissue was observed by HE staining. Nitric oxide (NO), myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD) levels in skin flap were determined by ELISA kits. mRNA and protein levels were determined by qPCR and Western blot respectively. RESULTS: D-allose alleviated the condition of pathological changes and raised the survival rate of skin flap injured by I/R. Moreover, D-allose suppressed NO, MPO and MDA while elevated SOD levels during I/R status. Furthermore, D-allose decreased MCP-1, TNF-α, IL-1ß and IL-6 levels in skin flap injured by I/R. In addition, D-allose inhibited MKP-1 expression and activated ERK1/2 pathway in skin flap injured by I/R. PD-98059 partially counteracted D-allose effects on I/R injury. CONCLUSIONS: D-allose exerted its protective function via inhibiting MKP-1expression and further activated ERK1/2 pathway to suppress the progress of oxidative stress, inflammation and necrosis, contributing to the survival of skin flap injured by I/R. Thus, D-allose was promising in the transplantation of skin flap.

Quercetin promotes human epidermal stem cell proliferation through the estrogen receptor/ß-catenin/c-Myc/cyclin A2 signaling pathway.

Skin epidermal stem cells (EpSCs) play an important role in wound healing. Quercetin is a phytoestrogen reported to accelerate skin wound healing, but its effect on EpSCs is unknown. In this study, we investigated the effect of quercetin on human EpSC proliferation and explored the underlying mechanisms. We found that quercetin at 0.1~1 µM significantly promoted EpSC proliferation and increased the number of cells in S phase. The pro-proliferative effect of quercetin on EpSCs was confirmed in cultured human skin tissue. Mechanistic studies showed that quercetin significantly upregulated the expressions of ß-catenin, c-Myc, and cyclins A2 and E1. Inhibitor for ß-catenin or c-Myc significantly inhibited quercetin-induced EpSC proliferation. The ß-catenin inhibitor XAV-939 suppressed quercetin-induced expressions of ß-catenin, c-Myc, and cyclins A2 and E1. The c-Myc inhibitor 10058-F4 inhibited the upregulation of c-Myc and cyclin A2 by quercetin. Pretreatment of EpSCs with estrogen receptor (ER) antagonist ICI182780, but not the G protein-coupled ER1 antagonist G15, reversed quercetin-induced cell proliferation and upregulation of ß-catenin, c-Myc, and cyclin A2. Collectively, these results indicate that quercetin promotes EpSC proliferation through ER-mediated activation of ß-catenin/c-Myc/cyclinA2 signaling pathway and ER-independent upregulation of cyclin E1 and that quercetin may accelerate skin wound healing through promoting EpSC proliferation. As EpSCs are used not only in clinic to treat skin wounds but also as seed cells in skin tissue engineering, quercetin is a useful reagent to expand EpSCs for basic research, skin wound treatment, and skin tissue engineering.

Role of the p38 mitogen-activated protein kinase signaling pathway in estrogen-mediated protection following flap ischemia-reperfusion injury.

Ischemia-reperfusion (I/R) injury often occurs during skin flap transplantation and results in tissue damage. Although estrogen treatment significantly alleviates this I/R injury-induced damage, the detailed molecular mechanism is not clear. In this study, a superficial epigastric artery flap I/R injury model was created in adult Wistar rats. Severe necrosis was observed in skin tissue after I/R injury. Histological examination of skin tissue revealed that I/R injury damages skin structure and results in neutrophil infiltration. Inflammation-related parameters, including neutrophil count, tumor necrosis factor-α, and interleukin-10 levels, were increased due to I/R injury. These pathological phenomena were reduced by estradiol treatment. Further investigation found that I/R injury triggers the p38 mitogen-activated protein kinase (p38-MAPK) pathway. The expression levels of p38-MAPK and phosphorylated p38-MAPK were increased after I/R injury. Estradiol increased the expression level of MAPK phosphatase-2, a putative phosphatase of p38, and reduced the levels of p38-MAPK and phosphorylated p38-MAPK. These results suggest that estradiol can improve skin flap survival, possibly by inhibiting neutrophil infiltration and the expression of p38-MAPK. This study provides an explanation for how estrogen alleviates I/R injury-induced damage that occurs during skin flap transplantation. In a rat pathological model, I/R injury leads to skin necrosis, skin structure damage, neutrophil infiltration, and inflammatory cytokine secretion, which are probably downstream effects of activation of the p38-MAPK pathway. On the other hand, estradiol treatment triggers the expression of MAPK phosphatase-2, a putative phosphatase of p38-MAPK, and reduced all examined pathological phenomena. Therefore, estrogen may reduce the deleterious effect of I/R injury on skin flap transplantation through modulating the p38-MAPK pathway.

Comparison of treatment outcomes between nonsurgical and surgical treatment of distal radius fracture in elderly: a systematic review and meta-analysis.

PURPOSE: The best treatment of distal radius fractures (DRFs) in the elderly is uncertain. The purpose of this meta-analysis was to compare the outcomes of surgical and nonsurgical management of DRFs in persons 65 years of age or older. METHODS: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until April 27, 2015 using the following search terms: distal radius fracture, conservative treatment, nonoperative treatment, nonsurgical treatment, surgical treatment, operative, elderly, and older. The primary outcome measure was DASH score, and secondary outcomes were functional and radiological assessments. The standard difference in post-treatment means was calculated for the outcomes to compare the two groups. RESULTS: Of 59 articles identified, eight studies with a total of 440 patients in the surgical groups and 449 in the control groups were included in the analysis. No significant differences in DASH score, VAS pain score, grip strength, wrist extension, pronation, or supination, and ulnar deviation were noted between the groups. The nonsurgical group had significantly greater wrist flexion, radial deviation, and ulnar variance and less radial inclination than the surgical group. CONCLUSIONS: Surgical and nonsurgical methods produce similar results in the treatment of DRFS in the elderly, and minor objective functional differences did not result an impact on subjective function outcome and quality of life.

Combined ipsilateral and contralateral second toe flaps for repair of finger degloving injury.

PURPOSE: The purpose of this report was to retrospectively review the results of treatment of degloving injury of the finger by use of combined ipsilateral second dorsal nail-skin flap and contralateral medial second toe flap. METHODS: From 2010 to 2012, seven fingers in seven patients with complete degloving injuries from the level of middle or distal phalanx were reconstructed with combined ipsilateral second dorsal nail-skin flap and contralateral medial second toe flap. The injured fingers included the index finger in four cases, and middle finger in three cases. The nerves of both the flaps were sutured to the bilateral common digital nerves. The donor site of second toe flap was covered with a full-thickness skin graft. RESULTS: All transferred flaps survived after surgery, and all postoperative courses were uneventful. During the follow-up period (mean of 15 months; ranging 6-20 months), the appearance of the reconstructed fingers was comparable with normal ones. The range of motion of the distal interphalangeal joint averaged 55 ± 5.8 degrees. The two point discrimination of the pulp ranged from 8 to > 15 mm (average, 11.3 mm). All the patients were able to walk without difficulty. The MHQ score averaged 59 ± 4.2 points and Maryland foot rating score averaged 92 ± 4.2 points. CONCLUSION: The ipsilateral second toe dorsal nail-skin flap combined with contralateral medial second toe flap may provide an alternative for the reconstruction of completely degloved fingers at the middle and the distal phalangeal level, with satisfactory functional and cosmetic results.

Distribution of pathogens and risk factors for post-replantation wound infection in patients with traumatic major limb mutilation.

PURPOSE: Even though replantation of limb mutilation is increasing, postoperative wound infection can result in increasing the financial and psychological burden of patients. Here, we sought to explore the distribution of pathogens and identify risk factors for postoperative wound infection to help early identification and managements of high-risk patients. METHODS: Adult inpatients with severed traumatic major limb mutilation who underwent replantation from Suzhou Ruixing Medical Group between November 09, 2014, and September 6, 2022 were included in this retrospective study. Demographic, and clinical characteristics, treatments, and outcomes were collected. Data were used to analyze risk factors for postoperative wound infection. RESULTS: Among the 249 patients, 185 (74.3%) were males, the median age was 47.0 years old. Postoperative wound infection in 74 (29.7%) patients, of whom 51 (20.5%) had infection with multi-drug resistant bacteria. Ischemia time (OR 1.31, 95% CI 1.13-1.53, P = 0.001), wound contamination (OR 6.01, 95% CI 2.38-15.19, P <0.001), and stress hyperglycemia (OR 23.37, 95% CI 2.30-236.93, P = 0.008) were independent risk factors, while the albumin level after surgery (OR 0.94, 95% CI 0.89-0.99, P = 0.031) was significant associated with the decrease of postoperative wound infection. Ischemia time (OR 1.21, 95% CI 1.05-1.40, P = 0.010), wound contamination (OR 8.63, 95% CI 2.91-25.57, P <0.001), and MESS (OR 1.32, 95% CI 1.02-1.71, P = 0.037 were independent risk factors for multi-drug resistant bacteria infection. CONCLUSIONS: Post-replantation wound infection was common in patients with severe traumatic major limb mutilation, and most were multi-drug resistant bacteria. Ischemia time and wound contamination were associated with the increase of postoperative wound infection, including caused by multi-drug resistant. Positive correction of hypoproteinemia and control of stress hyperglycemia may be beneficial.

Repair of a degloving injury of the thumb with a combined dorsal great toenail flap and dorsalis pedis flap: a case report.

Many methods for the repair of degloving injuries of the thumb have been reported, but none are entirely satisfactory. Herein, we report a method in which the injury is divided into the dorsal and palmar area for repair. A great toenail flap is used to repair the dorsal injury to restore the nail defect, and a dorsalis pedis flap is used to repair the palmar injury. The described technique provides good restoration of morphology and aesthetic outcome, good functional and sensory recovery, and is associated with minimal donor-site morbidity.

Combined light-cured and sacrificial hydrogels for fabrication of small-diameter bionic vessels by 3D bioprinting.

BACKGROUND: Bionic grafts can replace autologous tissue through tissue engineering in cases of cardiovascular disease. However, small-diameter vessel grafts remain challenging to precellularize. OBJECTIVE: Bionic small-diameter vessels with endothelial and smooth muscle cells (SMCs) manufactured with a novel approach. METHODS: A 1-mm-diameter bionic blood vessel was constructed by combining light-cured hydrogel gelatin-methacryloyl (GelMA) with sacrificial hydrogel Pluronic F127. Mechanical properties of GelMA (Young's modulus and tensile stress) were tested. Cell viability and proliferation were detected using Live/dead staining and CCK-8 assays, respectively. The histology and function of the vessels were observed using hematoxylin and eosin and immunofluorescence staining. RESULTS: GelMA and Pluronic were printed together using extrusion. The temporary Pluronic support was removed by cooling during GelMA crosslinking, yielding a hollow tubular construct. A bionic bilayer vascular structure was fabricated by loading SMCs into the GelMA bioink, followed by perfusion with endothelial cells. In the structure, both cell types maintained good cell viability. The vessel showed good histological morphology and function. CONCLUSION: Using light-cured and sacrificial hydrogels, we formed a small ca bionic vessel with a small caliber containing SMCs and endothelial cells, demonstrating an innovative approach for construction of bionic vascular tissues.

Transplantation of Ultra-Long Cross-Donor Conjoined Perforator Flaps with Multiple Blood Supply Sources for Wound Repair.

OBJECTIVE: There are reports about the surgical method and clinical efficacy of using ultra-long cross-donor perforator skin flap transplantation with multiple blood supply sources to repair wounds. METHOD: Between January 2013 and March 2019, 29 wounds were repaired using ultra-long skin flaps from the donor site of the chest, abdomen and anterolateral thigh. All patients were followed up on a regular basis with a view to the following: appearance of skin flap, function of recipient area and healing of donor area. RESULT: After the operation, all 28 skin flaps were fine. On the fifth day after the operation, one case of a 47-cm anterolateral thigh flap had dark skin color in the distal-most area measuring about 5 cm×4 cm, and the incision showed slow bleeding. In 11 cases, linear scars with soft edges and no obvious contractures were left in the donor area of the chest and abdomen. Eighteen cases with lateral femoral donor sites healed successfully, with linear scars forming without contracture. Three cases with lateral femoral donor sites had wide linear scars that were slightly above skin level and exhibited no contracture. CONCLUSION: Transplantation of ultra-long conjoined cross-donor perforator flaps with multiple blood supply is beneficial to wound repair and worthy of clinical promotion.

Morphological study of branches of lateral femoral circumflex artery based on digital subtraction angiography.

In this study, the digital subtraction angiography (DSA) data were used to describe the number, course, and distribution of the branches of the lateral circumflex femoral artery (LCFA), in order to provide an imaging basis for the application of the anterolateral thigh flap pedicled with each branch of the LCFA. The number, location, direction, and distribution of the branches of the LCFA were analyzed by selective DSA angiography in 113 patients who needed an anterolateral thigh flap to repair the wound. LCFA usually originates from the deep femoral artery or femoral artery and routinely sends out four main branches: ascending branch, transverse branch, oblique branch, and descending branch. The ascending branch is about 45 °outward and upward with the horizontal axis of the body; the transverse branch is roughly parallel to the horizontal axis of the body to the outside of the thigh or slightly upward or downward; the oblique branch is about 45 °outward and downward to the body's long axis or horizontal axis and gradually turns parallel to the body's long axis; the 5∼10 cm at the beginning of the descending branch is parallel to the long axis of the body, and the internal and external branches are separated near the midpoint of the line between the anterior superior iliac spine and the lateral edge of the patella. It is of high reference value to use DSA technology to analyze the morphological characteristics of LCFA.