Wound Healing and Therapy in Soft Tissue Defects of the Hand and Foot from a Surgical Point of View

Microvascular Muscle vs. Fascio-Cutaneous Free Flaps for Reconstruction of Plantar Load-Bearing Foot Defects-An International Survey

Background: The reconstruction of plantar load-bearing foot defects faces many plastic surgeons with a major challenge. The optimal patient- and defect-oriented reconstructive strategy must be selected. Methods: To analyze the current trends and recommendations in reconstruction of plantar load-bearing foot defects, we conducted an international survey among plastic surgeons querying them about their recommendations and experiences. Results: The survey revealed that the most common strategies for reconstruction of the foot sole are locoregional and microvascular free flaps, emphasizing the relevance of plastic surgery. Among microvascular free flaps, muscle and fascio-cutaneous free flaps are by far the most frequently used. The target qualities of the reconstructed tissue to be considered are manifold, with adherence being the most frequently mentioned. We observed a noteworthy correlation between the utilization of muscle flaps and a preference for adherence. In addition, we identified a substantial correlation between the usage of fascio-cutaneous free flaps and further target qualities, such as good skin quality and sensitivity. Conclusions: Our findings provide insights into the clinical reality and highlight important aspects that must be considered in reconstruction of the weight-bearing areas of the foot providing support in the selection of the appropriate therapy.

A treatment algorithm for reconstruction of soft tissue defects in the hand: a narrative review

Background and Objective

The hand is the highly specialized distal construct of the upper limb with complex and intricate anatomy. Soft tissue defects can compromise this and result in significant functional impairment. Choosing the optimal reconstructive modality is essential for the best functional recovery. The objective of this narrative review was to provide a treatment algorithm for soft tissue defects in the hand.

Methods

Relevant literature for the topic was searched from PubMed and Cochrane Database from year 1953 up till end of November 2022. Specified searches for randomized controlled trials, systematic reviews and reviews were performed.

Key Content and Findings

There are no randomized controlled trials published on this topic. There are six systematic reviews or meta-analyses published. Most of the literature still comprises on expert opinion and case reports with few previously proposed algorithms. Defect features, size, location and depth, patient related factors and available resources are the main determinants of the treatment strategy. In the hand, there are reasonable locoregional coverage options, but microsurgical options should be a routine alternative of the treatment repertoire. In the thumb and fingers, the reconstruction depends remarkably on injury extent.

Conclusions

Patient factors, surgical expertise, etiology, severity and goal of reconstruction will invariably have influence on the ultimate reconstruction performed, and algorithms may significantly help the surgical planning.

Characterizing the inherent activity of urinary bladder matrix for adhesion, migration, and activation of fibroblasts as compared with collagen-based synthetic scaffold

The mechanism of action underlying the intriguing prominent bioactivity of urinary bladder matrix (UBM) for in situ tissue regeneration of soft tissue defects remains to be elucidated. It is speculated that the activity of UBM for cell adhesion, migration, and activation is inherent. The bioactivity of UBM for in situ tissue regeneration and its relation with the structure and intact soluble components of UBM were investigated in comparison to a collagen-based scaffold, PELNAC (PEL). We isolated the soluble component of the two materials with urea buffer, and evaluated the respective effect of these soluble components on the in vitro adhesion and migration of L929 fibroblasts. The spatiotemporal pattern of endogenous-cell ingrowth into the scaffolds and cell activation were investigated using a model of murine subcutaneous implantation. UBM is more capable of promoting the adhesion, migration, and proliferation of fibroblasts than PEL in a serum-independent manner. In vivo, as compared with PEL, UBM exhibits significantly enhanced activity for fast endogenous cell ingrowth and produces a more prominent pro-regenerative and pro-remodeling microenvironment by inducing the expression of TGF-β1, VEGF, MMP-9, and murine type I collagen. Overall, our results suggest the prominent bioactivity of UBM for in situ tissue regeneration is inherent.

Small extracellular vesicles from mesenchymal stem cells: A potential Weapon for chronic non-healing wound treatment

Chronic non-healing wounds have posed a severe threat to patients mentally and physically. Behavior dysregulation of remaining cells at wound sites is recognized as the chief culprit to destroy healing process and hinders wound healing. Therefore, regulating and restoring normal cellular behavior is the core of chronic non-healing wound treatment. In recent years, the therapy with mesenchymal stem cells (MSCs) has become a promising option for chronic wound healing and the efficacy has increasingly been attributed to their exocrine functions. Small extracellular vesicles derived from MSCs (MSC-sEVs) are reported to benefit almost all stages of wound healing by regulating the cellular behavior to participate in the process of inflammatory response, angiogenesis, re-epithelization, and scarless healing. Here, we describe the characteristics of MSC-sEVs and discuss their therapeutic potential in chronic wound treatment. Additionally, we also provide an overview of the application avenues of MSC-sEVs in wound treatment. Finally, we summarize strategies for large-scale production and engineering of MSC-sEVs. This review may possibly provide meaningful guidance for chronic wound treatment with MSC-sEVs.

Topical vanadate improves tensile strength and alters collagen organisation of excisional wounds in a mouse model

Wound dehiscence, oftentimes a result of the poor tensile strength of early healing wounds, is a significant threat to the post-operative patient, potentially causing life-threatening complications. Vanadate, a protein tyrosine phosphatase inhibitor, has been shown to alter the organisation of deposited collagen in healing wounds and significantly improve the tensile strength of incisional wounds in rats. In this study, we sought to explore the effects of locally administered vanadate on tensile strength and collagen organisation in both the early and remodelling phases of excisional wound healing in a murine model. Wild-type mice underwent stented excisional wounding on their dorsal skin and were divided equally into three treatment conditions: vanadate injection, saline injection control and an untreated control. Tensile strength testing, in vivo suction Cutometer analysis, gross wound measurements and histologic analysis were performed during healing, immediately upon wound closure, and after 4 weeks of remodelling. We found that vanadate treatment significantly increased the tensile strength of wounds and their stiffness relative to control wounds, both immediately upon healing and into the remodelling phase. Histologic analysis revealed that these biomechanical changes were likely the result of increased collagen deposition and an altered collagen organisation composed of thicker and distinctly organised collagen bundles. Given the risk that dehiscence poses to all operative patients, vanadate presents an interesting therapeutic avenue to improve the strength of post-operative wounds and unstable chronic wounds to reduce the risk of dehiscence.

Gelatin and Bioactive Glass Composites for Tissue Engineering: A Review

Nano-/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique anti-bacterial, anti-inflammatory, and anti-cancer functionalities. Recently, composites based on biopolymers and BG particles have been developed with various state-of-the-art techniques for tissue engineering. Gelatin, a semi-synthetic biopolymer, has attracted the attention of researchers because it is derived from the most abundant protein in the body, viz., collagen. It is a polymer that can be dissolved in water and processed to acquire different configurations, such as hydrogels, fibers, films, and scaffolds. Searching "bioactive glass gelatin" in the tile on Scopus renders 80 highly relevant articles published in the last ~10 years, which signifies the importance of such composites. First, this review addresses the basic concepts of soft and hard tissue engineering, including the healing mechanisms and limitations ahead. Then, current knowledge on gelatin/BG composites including composition, processing and properties is summarized and discussed both for soft and hard tissue applications. This review explores physical, chemical and mechanical features and ion-release effects of such composites concerning osteogenic and angiogenic responses in vivo and in vitro. Additionally, recent developments of BG/gelatin composites using 3D/4D printing for tissue engineering are presented. Finally, the perspectives and current challenges in developing desirable composites for the regeneration of different tissues are outlined.