Emodin activates autophagy to suppress oxidative stress and pyroptosis via mTOR-ULK1 signaling pathway and promotes multi-territory perforator flap survival.

BACKGROUND: Multi-territory perforator flap reconstruction has been proven effective in treating large skin and soft tissue defects in clinical settings. However, in view of that the multi-territory perforator flap is prone to partial postoperative necrosis, increasing its survival is the key to the success of reconstruction. In this study, we aimed to clarify the effect of emodin on multi-territory perforator flap survival. METHODS: Flap survival was assessed by viability area analysis, infrared laser imaging detector, HE staining, immunohistochemistry, and angiography. Western blotting, immunofluorescence assays, and real-time fluorescent quantitative PCR were performed to detect the indicators of oxidative stress, pyroptosis and autophagy. RESULTS: After emodin treatment, the multi-territory perforator flap showed a significantly increased survival rate, which was shown to be closely related to the inhibition of oxidative stress and pyroptosis and enhanced autophagy. Meanwhile, the use of autophagy inhibitor 3 MA was found to reverse the inhibitory effects of emodin on oxidative stress and pyroptosis and weaken the improving effect of emodin on flap survival, suggesting that autophagy plays a critical role in emodin-treated flaps. Interestingly, our mechanistic investigations revealed that the positive effect of emodin on multi-territory perforator flap was attributed to the mTOR-ULK1 signaling pathway activation. CONCLUSIONS: Emodin can inhibit oxidative stress and pyroptosis by activating autophagy via the mTOR-ULK1 pathway, thereby improving the multi-territory perforator flap survival.

M2 macrophage-derived exosomes induce angiogenesis and increase skin flap survival through HIF1AN/HIF-1α/VEGFA control.

BACKGROUND: Skin flap transplantation is a routine strategy in plastic and reconstructive surgery for skin-soft tissue defects. Recent research has shown that M2 macrophages have the potential for pro-angiogenesis during tissue healing. METHODS: In our research, we extracted the exosomes from M2 macrophages(M2-exo) and applied the exosomes in the model of skin flap transplantation. The flap survival area was measured, and the choke vessels were assessed by morphological observation. Hematoxylin and eosin (H&E) staining and Immunohistochemistry were applied to assess the neovascularization. The effect of M2-exo on the function of Human umbilical vein endothelial cells (HUVECs) was also investigated. We also administrated 2-methoxyestradiol (2-ME2, an inhibitor of HIF-1α) to explore the underlying mechanism. We tested the effects of M2-Exo on the proliferation of HUVECs through CCK8 assay and EdU staining assay. RESULTS: The survival area and number of micro-vessels in the skin flaps were increased in the M2-exo group. Besides, the dilation rate of choke vessels was also enhanced in the M2-exo group. Additionally, compared with the control group, M2-exo could accelerate the proliferation, migration and tube formation of HUVECs in vitro. Furthermore, the expression of the pro-angiogenesis factors, HIF-1α and VEGFA, were overexpressed with the treatment of the M2-exo. The expression of HIF1AN protein level was decreased in the M2-exo group. Finally, treatment with HIF-1α inhibitor reverses the pro-survival effect of M2-exo on skin flaps by interfering with the HIF1AN/HIF-1α/VEGFA signaling pathway. CONCLUSION: This study showed that M2-exosomes promote skin flap survival by enhancing angiogenesis, with HIF1AN/HIF-1α/VEGFA playing a crucial role in this process.

Hypoxic mesenchymal stem cell-derived exosomes promote the survival of skin flaps after ischaemia-reperfusion injury via mTOR/ULK1/FUNDC1 pathways.

Flap necrosis, the most prevalent postoperative complication of reconstructive surgery, is significantly associated with ischaemia-reperfusion injury. Recent research indicates that exosomes derived from bone marrow mesenchymal stem cells (BMSCs) hold potential therapeutic applications in several diseases. Traditionally, BMSCs are cultured under normoxic conditions, a setting that diverges from their physiological hypoxic environment in vivo. Consequently, we propose a method involving the hypoxic preconditioning of BMSCs, aimed at exploring the function and the specific mechanisms of their exosomes in ischaemia-reperfusion skin flaps. This study constructed a 3 × 6 cm2 caudal superficial epigastric skin flap model and subjected it to ischaemic conditions for 6 h. Our findings reveal that exosomes from hypoxia-pretreated BMSCs significantly promoted flap survival, decrease MCP-1, IL-1ß, and IL-6 levels in ischaemia-reperfusion injured flap, and reduce oxidative stress injury and apoptosis. Moreover, results indicated that Hypo-Exo provides protection to vascular endothelial cells from ischaemia-reperfusion injury both in vivo and in vitro. Through high-throughput sequencing and bioinformatics analysis, we further compared the differential miRNA expression profiles between Hypo-Exo and normoxic exosomes. Results display the enrichment of several pathways, including autophagy and mTOR. We have also elucidated a mechanism wherein Hypo-Exo promotes the survival of ischaemia-reperfusion injured flaps. This mechanism involves carrying large amounts of miR-421-3p, which target and regulate mTOR, thereby upregulating the expression of phosphorylated ULK1 and FUNDC1, and subsequently further activating autophagy. In summary, hypoxic preconditioning constitutes an effective and promising method for optimizing the therapeutic effects of BMSC-derived exosomes in the treatment of flap ischaemia-reperfusion injury.

Exosomes derived from LPS-preconditioned bone marrow-derived MSC modulate macrophage plasticity to promote allograft survival via the NF-κB/NLRP3 signaling pathway.

OBJECTIVES: This study investigated whether exosomes from LPS pretreated bone marrow mesenchymal stem cells (LPS pre-MSCs) could prolong skin graft survival. METHODS: The exosomes were isolated from the supernatant of MSCs pretreated with LPS. LPS pre-Exo and rapamycin were injected via the tail vein into C57BL/6 mice allografted with BALB/c skin; graft survival was observed and evaluated. The accumulation and polarization of macrophages were examined by immunohistochemistry. The differentiation of macrophages in the spleen was analyzed by flow cytometry. For in vitro, an inflammatory model was established. Specifically, bone marrow-derived macrophages (BMDMs) were isolated and cultured with LPS (100 ng/ml) for 3 h, and were further treated with LPS pre-Exo for 24 h or 48 h. The molecular signaling pathway responsible for modulating inflammation was examined by Western blotting. The expressions of downstream inflammatory cytokines were determined by Elisa, and the polarization of macrophages was analyzed by flow cytometry. RESULTS: LPS pre-Exo could better ablate inflammation compared to untreated MSC-derived exosomes (BM-Exo). These loaded factors inhibited the expressions of inflammatory factors via a negative feedback mechanism. In vivo, LPS pre-Exo significantly attenuated inflammatory infiltration, thus improving the survival of allogeneic skin graft. Flow cytometric analysis of BMDMs showed that LPS pre-Exo were involved in the regulation of macrophage polarization and immune homeostasis during inflammation. Further investigation revealed that the NF-κB/NLRP3/procaspase-1/IL-1ß signaling pathway played a key role in LPS pre-Exo-mediated regulation of macrophage polarization. Inhibiting NF-κB in BMDMs could abolish the LPS-induced activation of inflammatory pathways and the polarization of M1 macrophages while increasing the proportion of M2 cells. CONCLUSION: LPS pre-Exo are able to switch the polarization of macrophages and enhance the resolution of inflammation. This type of exosomes provides an improved immunotherapeutic potential in prolonging graft survival.

The rare complication of vascular malformations of the limb after sclerotherapy: a report of 3 cases and brief literature review.

BACKGROUND: Vascular malformations are common but complicated types of disease in infants, with unclear causes and lack of effective prevention. The symptoms usually do not disappear and tend to progress without medical intervention. It is extremely necessary to choose correct treatment options for different types of vascular malformations. A large number of studies have confirmed that sclerotherapy has a tendency to become the first-line treatment in near future, but it is also associated with mild or severe complications. Furthermore, to our knowledge, the serious adverse event of progressive limb necrosis has not been systematically analyzed and reported in the literature. CASE PRESENTATION: Three cases (two females and one male) were presented who were all diagnosed as vascular malformations and were treated by several sessions of interventional sclerotherapy. Their previous medical records showed the use of several sclerosants in different sessions including Polidocanol and Bleomycin. The sign of limb necrosis did not occur during the first sclerotherapy, but after the second and third sessions. Furthermore, the short-term symptomatic treatment could improve the necrosis syndrome, but could not change the outcome of amputation. CONCLUSION: Sclerotherapy undoubtedly tends to be the first-line treatment in near future, but the adverse reactions still remain major challenges. Awareness of progressive limb necrosis after sclerotherapy and timely management by experts in centers of experience of this complication can avoid amputation.

The free chimeric medial sural artery perforator flap for individualised and three-dimensional reconstruction of complex soft-tissue defects in extremities.

Trauma or lesion resection often causes complex wounds with deep soft tissue defects in extremities. Simply covering with a skin flap will leave a deep dead space resulting in infection, non-healing wounds, and poor long-term outcomes. Thus, effectively reconstructing complex wounds with dead space leaves a clinical challenge. This manuscript presents our experience using chimeric medial sural artery perforator (cMSAP) flap, to reconstruct complex soft tissue defects of the extremities, thereby exploring broader analysis and indications for future reference. Between March 2016 and May 11, 2022, patients (8 males and 3 females) with a mean age of 41 years (range from 26 to 55 years) underwent reconstructive surgery with the cMSAP flap. The cMSAP flap consists of an MSAP skin paddle and a medial sural muscle paddle. The size of the MSAP skin paddle ranged between 9 × 5 cm and 20 × 6 cm, and the size of the medial sural muscle paddle ranged between 2 × 2 cm and 14 × 4 cm. Primary closure of the donor site was achieved in all cases. Of the 11 patients, the cMSAP flap survived in 10 cases. The vascular compromise occurred in one special case and was treated with surgical procedures. The mean follow-up duration was 16.5 months (range of 5-25 months). Most patients present satisfactory cosmetic and functional results. The free cMSAP flap is a good option for reconstructing complex soft tissue defects with deep dead space in extremities. The skin flap can cover the skin defect, and the muscle flap can fill the dead space against infection. In addition, three types of cMSAP flaps can be used in a broader range of complex wounds. This procedure can achieve an individualised and three-dimensional reconstruction of the defects and minimise the donor site morbidities.

Identification of sensory and motor nerve fascicles by immunofluorescence staining after peripheral nerve injury.

BACKGROUND: Inappropriate matching of motor and sensory fibers after nerve repair or nerve grafting can lead to failure of nerve recovery. Identification of motor and sensory fibers is important for the development of new approaches that facilitate neural regeneration and the next generation of nerve signal-controlled neuro-prosthetic limbs with sensory feedback technology. Only a few methods have been reported to differentiate sensory and motor nerve fascicles, and the reliability of these techniques is unknown. Immunofluorescence staining is one of the most commonly used methods to distinguish sensory and motor nerve fibers, however, its accuracy remains unknown. METHODS: In this study, we aim to determine the efficacy of popular immunofluorescence markers for motor and sensory nerve fibers. We harvested the facial (primarily motor fascicles) and sural (primarily sensory fascicles) nerves in rats, and examined the immunofluorescent staining expressions of motor markers (choline acetyltransferase (ChAT), tyrosine kinase (TrkA)), and sensory markers [neurofilament protein 200 kDa (NF-200), calcitonin gene-related peptide (CGRP) and Transient receptor potential vanillic acid subtype 1 (TRPV1)]. Three methods, including the average area percentage, the mean gray value, and the axon count, were used to quantify the positive expression of nerve markers in the immunofluorescence images. RESULTS: Our results suggest the mean gray value method is the most reliable method. The mean gray value of immunofluorescence in ChAT (63.0 ± 0.76%) and TRKA (47.6 ± 0.43%) on the motor fascicles was significantly higher than that on the sensory fascicles (ChAT: 49.2 ± 0.72%, P < 0.001; and TRKA: 29.1 ± 0.85%, P < 0.001). Additionally, the mean gray values of TRPV1 (51.5 ± 0.83%), NF-200 (61.5 ± 0.62%) and CGRP (37.7 ± 1.22%) on the motor fascicles were significantly lower than that on the sensory fascicles respectively (71.9 ± 2.32%, 69.3 ± 0.46%, and 54.3 ± 1.04%) (P < 0.001). The most accurate cutpoint occurred using CHAT/CRCP ratio, where a value of 0.855 had 100% sensitivity and 100% specificity to identify motor and sensory nerve with an area under the ROC curve of 1.000 (P < 0.001). CONCLUSIONS: A combination of ChAT and CGRP is suggested to distinguish motor and sensory nerve fibers.

Large wounds reconstruction of the lower extremity with combined latissimus dorsi musculocutaneous flap and flow-through anterolateral thigh perforator flap transfer.

BACKGROUND: Management of large wounds of the lower extremities remains a challenge for plastic and reconstructive surgeons. Herein, a surgical technique and clinical algorithm using the combined transfer of a latissimus dorsi (LD) musculocutaneous flap and flow-through anterolateral thigh (ALT) perforator flap for the treatment of extensive soft-tissue defects is described. METHODS: From January 2012 to September 2018, 12 patients (six men and six women) aged 6-37 years, sustained injuries in road traffic accidents with large soft-tissue defects in the lower extremities. Seven cases were Gustillo Anderson type IIIB open fractures and two cases were Gustillo Anderson type IIIC open fractures. Two wounds were located in the knee joint, four in the calf, and six in the ankle and foot. The skin defect size ranged from 25 × 20 cm2 to 36 × 25 cm2 . All patients in this series underwent reconstruction using combined transfer of the LD musculocutaneous flap and flow-through ALT perforator flap, wherein the LD was attached through its pedicle to the distal continuation of the ALT flap. RESULTS: The size of the flow-through ALT perforator flaps ranged from 13.5 × 6.5 cm2 to 31 × 8.5 cm2 . The size of the LD musculocutaneous skin paddle ranged from 25 × 6 cm2 to 34 × 7 cm2 , and that of the muscle paddle ranged from 13 × 3.5 cm2 to 30 × 11 cm2 . One patient experienced postoperative thrombosis of the venous pedicle, and the flap was salvaged after emergency re-exploration and thrombectomy. No other complications were observed postoperatively. The mean follow-up period was 26.8 months. All patients were able to ambulate independently at the end of the follow-up period. CONCLUSIONS: The combined transfer of the LD musculocutaneous flap and flow-through ALT perforator flap ensured adequate surface coverage, making it a feasible procedure for large soft-tissue defects.

Macrophage Activation in the Dorsal Root Ganglion in Rats Developing Autotomy after Peripheral Nerve Injury.

Autotomy, self-mutilation of a denervated limb, is common in animals after peripheral nerve injury (PNI) and is a reliable proxy for neuropathic pain in humans. Understanding the occurrence and treatment of autotomy remains challenging. The objective of this study was to investigate the occurrence of autotomy in nude and Wistar rats and evaluate the differences in macrophage activation and fiber sensitization contributing to the understanding of autotomy behavior. Autotomy in nude and Wistar rats was observed and evaluated 6 and 12 weeks after sciatic nerve repair surgery. The numbers of macrophages and the types of neurons in the dorsal root ganglion (DRG) between the two groups were compared by immunofluorescence studies. Immunostaining of T cells in the DRG was also assessed. Nude rats engaged in autotomy with less frequency than Wistar rats. Autotomy symptoms were also relatively less severe in nude rats. Immunofluorescence studies revealed increased macrophage accumulation and activation in the DRG of Wistar rats. The percentage of NF200+ neurons was higher at 6 and 12 weeks in Wistar rats compared to nude rats, but the percentage of CGRP+ neurons did not differ between two groups. Additionally, macrophages were concentrated around NF200-labeled A fibers. At 6 and 12 weeks following PNI, CD4+ T cells were not found in the DRG of the two groups. The accumulation and activation of macrophages in the DRG may account for the increased frequency and severity of autotomy in Wistar rats. Our results also suggest that A fiber neurons in the DRG play an important role in autotomy.

Use of a sequential chimeric perforator flap for one-stage reconstruction of complex soft tissue defects of the extremities.

BACKGROUND: One-stage reconstruction of complex soft tissue defects of the extremities is a challenging problem. Repair of complex soft tissue defects requires adequate skin tissues to cover the large surface wound and special tissues for obliterating the dead space. The chimeric flap is one of the most popular approaches for reconstruction of complex soft tissue defects. However, the problems of donor-site morbidity and inability to repair very large defects at one-stage remain. The purpose of this study was to present our clinical experience using sequential chimeric perforator flaps for reconstruction of complex extremity defects with primary closure of the donor site. METHODS: From August 2013 to March 2017, 12 patients with complex soft tissue defects underwent extremity reconstruction using sequential chimeric perforator flaps, which were composed of a chimeric anterolateral thigh perforator (ALTP) flap and an additional free perforator flap. The skin paddles were placed side-by-side to cover the large surface soft tissue defects, and the muscle component was used to obliterate the dead space. Of these patients, one was injured by a crushing accident, while the other 11 patients were injured in traffic accidents. RESULTS: The size of the skin paddles ranged from 26 cm × 8 cm-10 cm × 6 cm to 30 cm × 8.5 cm-29 cm × 9 cm. The muscle paddle size ranged from 2 cm × 3 cm × 4 cm to 22 cm × 4 cm × 2 cm. All-components of the sequential chimeric flaps survived in all-patients. Vascular compromise was observed in one case. One case suffered minor wound-edge necrosis and was treated conservatively. Primary closure of donor-site was successfully achieved in all-patients, and all-donor-site wounds healed uneventfully. The mean follow-up time was 15.25 months. Most of the cases showed a satisfactory contour, and only two patients presented with mildly bulky appearance that treated with a debulking procedure. CONCLUSIONS: The sequential chimeric perforator flap is an alternative procedure for reconstruct complex soft tissue defects of the extremities. This approach allows for flexible design, a larger cutaneous area, and low donor site morbidity.

Versatile design of compound vastus lateralis muscle and anterolateral thigh musculocutaneous perforator free flaps for customized reconstruction of complex skin and soft tissue defects in the extremities.

BACKGROUND: Compound anterolateral thigh flaps are popular for three-dimensional reconstruction of complex soft tissue defects. We present our 10-year experience using compound vastus lateralis (VL) muscle and anterolateral thigh musculocutaneous perforator (ALTP) flaps, and introduce three versatile customizations of this flap for individualized reconstruction of complex three-dimensional soft tissue defects. METHODS: From May 2008 to June 2017, compound VL muscle and ALTP flaps were performed in 67 consecutive patients aged 14-75 years (62 men and 5 women). The defects were in either the lower (n = 53) or upper extremity (n = 14), and ranged in size from 8 × 4 cm2 to 25 × 6 cm2. Dead space volume ranged from 4 × 2 × 1 cm3 to 20 × 3 × 2 cm3, and all flaps were harvested from patients' thighs as one of three types. In type A, a single perforator supplied both the skin and muscle components, with the vascular bundle penetrating the muscle component. In type B, a single perforator supplied both skin and muscle components with separate branches to the skin and muscle. In type C, separate vessels supplied the skin and muscle. RESULTS: In the 67 patients, 65 flaps survived, and the donor site was closed directly. Vascular compromise occurred in four patients on the first postoperative day. Two flaps were salvaged after emergency re-exploration. Flap loss occurred in two patients, and these defects were repaired using other flaps. The follow-up period ranged from 8 to 60 months (mean, 11.9 months). All flaps had satisfactory appearance and texture, and no patients experienced limited hip and knee joint mobility from the donor site operation. CONCLUSIONS: Compound VL muscle and ALTP flaps are a reliable option to reconstruct complex defects of the extremities. Identifying three flap types allowed for more precise customization to cover complex defects with limited donor site morbidity.

A Design for the Dual Skin Paddle Circumflex Scapular Artery Perforator Flap for the Reconstruction of Complex Soft-Tissue Defects in Children: Anatomical Study and Clinical Applications.

BACKGROUND: The main drawbacks of the use of the circumflex scapular artery perforator (CSAP) flap for complex soft-tissue defect repair are the limitation of skin paddle size, which can be harvested to allow precise wound coverage and primary closure of the donor site. We developed a variant of the dual skin paddle CSAP flap to extend its applications and minimize donor-site morbidity when reconstructing complex soft-tissue defects in children. METHODS: A detailed anatomical investigation of circumflex scapular artery (CSA) branches was conducted using a standardized injection of lead oxide in 25 fresh cadavers. Dual skin paddle CSAP flaps were harvested for the reconstruction of complex defects in the extremities in 16 children. Three types of dual skin paddle CSAP flap were used in this study: transverse chain-shaped, oblique chain-shaped, and trefoil-shaped flaps. RESULTS: Three CSA branching patterns with superior branch diameters were observed: 34% of CSAs were of the transverse branch dominant type, 54% were of the descending branch dominant type, and 12% were of the codominant type. Sixteen dual skin paddle CSAP flaps were elevated successfully; they were of the transverse chain-shaped type in 2 cases, the oblique chain-shaped type in 9 cases, and the trefoil-shaped type in 5 cases. All flaps survived postoperatively. Primary closure of the donor site was achieved in all cases. CONCLUSIONS: The CSA system is an appropriate source for harvesting dual skin paddle CASP flap. Use of this flap for the reconstruction of complex soft-tissue defects in the extremities in children is an alternative approach that reduces morbidity and improves the cosmetic outcome at the donor site.

Reconstruction of Large Soft Tissue Defects of the Extremities in Children Using the Kiss Deep Inferior Epigastric Artery Perforator Flap to Achieve Primary Closure of Donor Site.

BACKGROUND: The closure of massive skin defects remains challenging, particularly in children. In this report, we describe a technique to achieve primary donor site closure using the kiss deep inferior epigastric perforator (DIEP) flap for the reconstruction of large soft tissue defects located in the extremities of children. METHODS: From May 2011 to May 2016, a retrospective analysis was conducted on 10 pediatric patients with extensive soft tissue defects and reconstruction with double-skin paddle DIEP flap. After harvesting the flap, the skin paddle was divided into 2 separate paddles with a common vascular supply, and then the 2 paddles were sutured side by side through translating 2 paddles or rotating one of the paddles by 90 or 180 degrees, effectively doubling the width of the flap and rejoining it at the recipient site. Data on patient age, medical history, defect size, flap dimensions, recipient vessels, donor site closure, complications, and follow-up were reviewed retrospectively. RESULTS: Nine children had major soft tissue defects of the lower limb, and the remaining one had an upper limb defect. Only 1 case was complicated by partial necrosis of 1 paddle. Primary donor site closure was accomplished in all cases. The flaps were well matched on texture and contour, except that the 2 flaps were bulky at postoperative follow-up. There was no donor site breakdown, with only a slightly noticeable linear scar. CONCLUSION: The kiss DIEP flap could be an alternative for reconstruction of large soft tissue defects of the extremities in children, with lower morbidity and improved cosmetic of the donor site.

Catheter-Based Computed Tomography Angiography in Anterolateral Thigh Perforator Mapping of Chinese Patients.

BACKGROUND: During reconstructive surgery, anterolateral thigh (ALT) flap harvest is challenging due to variation and uncertainty in perforator distribution. We performed a pilot study to identify the predictive value of catheter-based computed tomography angiography (C-CTA) and traditional CTA (T-CTA) in ALT perforator mapping for patients whose ALT perforators were difficult to identify. METHODS: Thirty-four consecutive T-CTA/C-CTA-mapped ALT flaps were evaluated for extremity reconstruction. The perforator location, origin, and course were compared between T-CTA/C-CTA imaging and intraoperative findings. The mapping efficiency of T-CTA and C-CTA was compared thoroughly. RESULTS: Among the 34 ALT thigh flaps, 117 (36) of the 130 perforators identified intraoperatively were visible on C-CTA (T-CTA) in a subgroup of Chinese limb trauma patients with limited activity. C-CTA showed a satisfactory efficiency in perforator mapping, which was much better than the efficiency of T-CTA. C-CTA also showed a much better sensitivity (90.00 vs. 27.69%), specificity (94.74 vs. 66.67%), and accuracy (91.07 vs. 36.69%), and a much lower false-positive (1.68 vs. 26.53%), and false-negative rate (10.00 vs. 72.31%). Moreover, C-CTA could accurately predict the origin and septocutaneous or intramuscular course in all identified perforators. All flaps were elevated successfully and survived. CONCLUSION: C-CTA outperforms T-CTA in the preoperative perforator mapping of ALT flaps in a subgroup of Chinese limb trauma patients. C-CTA should be the method of choice for perforator mapping in patients whose ALT flaps are intended for extremity reconstruction.

Use of Flow-Through Anterolateral Thigh Perforator Flaps in Reconstruction of Complex Extremity Defects.

BACKGROUND: The flow-through flap has been widely utilized for reconstruction of complex defects of the extremities as it can be used for arterial reconstruction and soft-tissue coverage simultaneously. This study describes our clinical experience with the application of the flow-through anterolateral thigh perforator (ALTP) flap for reconstruction of complex defects of the extremities. METHODS: From January 2008 to June 2011, we retrospectively analyzed 16 patients with complex defects in the limbs. In two patients the defects occurred after undergoing wide excision of chronic ulcer, while 14 defects were due to trauma. All patients in this series underwent reconstruction with the flow-through ALTP flap. Applications of flow-through performed include preserving the recipient artery flow, rebuilding the major artery gap, bridging the artery and concomitant vein simultaneously, and combining the ALTP with another free flap. RESULTS: Flow-through ALTP flaps were used to preserve recipient flow (n = 5), rebuild the vessel gap (n = 2), bridge the artery and concomitant vein simultaneously (n = 2), and in combination with another free flap (n = 7). Follow-up ranged from 3 to 36 months (mean, 12 months). All flaps were successful; only two combination flaps required reexploration because of vessel crisis, and two patients suffered minor degrees of wound-edge necrosis. The donor sites healed well in all cases, without any complications. CONCLUSION: Our experience showed that the flow-through ALTP flap is reliable and suitable for reconstruction of complex defects of the extremities, as well as for various other clinical purposes.

Special-form radial collateral artery perforator flaps for the reconstruction of complex hand defects.

BACKGROUND: The reconstruction of complex wounds of the hand still has challenges in achieving aesthetic, functional and sensory recovery. We presented our experience of using the polyfoliate and chimeric radial collateral artery perforator flaps (RCAPF) to repair complex hand defects, aiming to explore the feasibility of special-form RCAPFs in hand coverage and enhance the comprehension of their respective indications. METHODS: From June 2014 to March 2021, 26 cases (19 males and 7 females, mean 44.4 years) underwent defect and sensation reconstruction of their hands with special-form RCAPFs, which manifested as multiple adjacent or irregular single wounds and composite tissue defects complicated with a degree of nerve injury. The clinical effects of the free RCAPFs were evaluated by integrating the postoperative and long-term follow-up outcomes of all cases. RESULTS: Altogether 8 polyfoliate flaps, 17 chimeric flaps and 1 polyfoliate-chimeric flap were harvested. Of them, 23 flaps survived uneventfully in one stage. Venous congestion occurred in 3 cases, two of which survived through vascular exploration and another one was finally repaired by the contralateral RCAPF. The follow-up results showed that the appearance of both the recipient and donor sites mostly recovered satisfactory. All the bone flaps properly healed. The BMRC sensory evaluation results of all skin flaps were S4 in 8 flaps, S3 in 18 flaps, and S2 in 9 flaps. CONCLUSIONS: The free RCAPFs can be designed in various forms with a reliable blood supply, contributing to reconstructing simple and multiple wounds of the hand with or without bone defects and dead space.