Development and validation of cryopreserved or freeze-dried decellularized human dermis for transplantation

For decades, dermal tissue grafts have been used in various regenerative, reconstructive, and augmentative procedures across the body. To eliminate antigenicity and immunogenic response while still preserving the individual components and collective structural integrity of the extracellular matrix (ECM), dermis can be decellularized. Acellular dermal matrix (ADM) products like such are produced to accurately serve diverse clinical purposes. The aim of the present study is to evaluate the efficacy of a novel decellularization protocol of the human dermis, which eliminates residual human genetic material without compromising the biomechanical integrity and collagenous content of the tissue. Moreover, a freeze-drying protocol was validated. The results showed that though our decellularization protocol, human dermis can be decellularized obtaining a biocompatible matrix. The procedure is completely realized in GMP aseptic condition, avoiding tissue terminal sterilization.

Decellularized Human Dermis for Orthoplastic Extremity Reconstruction

The reconstruction of patients who possess multi morbid medical histories remains a challenge. With the ever-increasing number of patients with diabetes, infections, and trauma, there is a consistent need for promotion of soft tissue healing and a reliable substrate to assist with every aspect of soft tissue reconstruction, as well as the loss of fascial domain. Several proprietary products filled some of these needs but have failed to fulfill the needs of the clinician when faced with reconstructing multiple soft tissue systems, such as the integument and the musculoskeletal system. In this paper we discuss the use of decellularized human dermis (DermaPure®, Tissue Regenix, Universal City, TX, USA) through which a unique human tissue processing technique (dCELL® technology, Tissue Regenix, Universal City, TX, USA) and the creation of multiple product forms have proven to exhibit versatility in a wide range of clinical needs for successful soft tissue reconstruction. The background of human tissue processing, basic science, and early clinical studies are detailed, which has translated to the rationale for the success of this unique soft tissue substrate in orthoplastic reconstruction, which is also provided here in detail.

Usage of Dermal Regeneration Templates (Pelnac) for Coverage of Exposed Hand Tendons in Acute Setting

Background

The loss of soft tissue coverage of tendons is a challenging reconstructive problem after acute hand trauma. Subsequent tendon adhesions and the loss of range of movement in addition to the poor aesthetic outcome and donor site scarring should be avoided when deciding the plan of management. Pelnac is one of the commonly used skin substitutes in reconstructive surgery that can be used for coverage of exposed tendons, but the postoperative functional outcome needs to be addressed in detail.

Methods

Twenty-six patients with acute isolated tendon injuries distal to the wrist joint were included. Two-stage reconstructive procedures were performed; the first one was the application of Pelnac. The second stage was carried out after the complete integration of Pelnac via the application of a split-thickness graft. The function outcome assesses the return of the normal range of motion to the affected hand and the QuickDASH score questionnaire. The aesthetic outcome was assessed using the Vancouver scar scale.

Results

The Pelnac was integrated in 100% of cases, with complete grafts taken in 22 of 26 patients. The mean QuickDASH score was 20.5 ± 15.7, and mean Vancouver scar scale was 3.53 ± 3.2. The full range of motion returned in 22 of 26 patients.

Conclusions

Using Pelnac to cover the exposed hand tendons in an acute setting is a convenient and efficient procedure with minimal morbidity. It can offer a good option for their coverage with preservation of hand function and acceptable aesthetic outcome.

Mini-Review: Tendon-Exposed Wound Treatments

BACKGROUND

Tendon-exposed wounds are complex injuries with challenging reconstructions and no unified treatment mode. Furthermore, insufficient tissue volume and blood circulation disorders affect healing, which increases pain for the patient and affects their families and caretakers.

REVIEW

As modern medicine advances, considerable progress has been made in understanding and treating tendon-exposed wounds, and current research encompasses both macro-and micro-studies. Additionally, new treatment methods have emerged alongside the classic surgical methods, such as new dressing therapies, vacuum sealing drainage combination therapy, platelet-rich plasma therapy, and live-cell bioengineering.

CONCLUSIONS

This review summarizes the latest treatment methods for tendon-exposed wounds to provide ideas and improve their treatment.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Dermal Matrices: Game Changers in Leg and Foot Soft Tissue Reconstruction? A Case Series

The present article aims to present the use of dermal matrices in severe degloving, avulsion, and necrotizing injuries of the leg and foot in 3 patients. Conventional reconstruction would require the use of free flaps, since exposure of vessels, nerves, joints, and tendons rendered the mere resurfacing with skin grafts insufficient, and extensive cutaneous detachment precluded the use of local fasciocutaneous flaps. All injuries underwent thorough and repeated surgical debridements and wash outs, followed by negative pressure wound therapy (NPWT). Once negative tissue cultures were obtained, the extremities were resurfaced with dermal matrix and immediately covered by split thickness skin grafts. NPWT on the grafted area for a week effectively secured the grafts on the recipient area. Complete healing was achieved in all grafted areas within 7 to 12 days. The function of joints and tendons as well as the quality of resurfacing at the weight bearing areas were tested and found satisfactory within a follow-up period of 5 to 15 months. The use of combined NPWT and dermal matrices in carefully selected patients provides a reliable and durable reconstructive option for leg and foot injuries with satisfactory functional outcomes.

Management of Hardware-Exposed Soft Tissue Defects Using Dermal Substitutes and Negative Pressure Wound Therapy

INTRODUCTION

Reconstruction of complex injuries of the extremities with full-thickness wounds is a challenging but important task. If primary closure is not feasible, more complex procedures are required, such as split-thickness skin graft or flap surgery. Recently, several studies have shown good results when combined with negative pressure wound therapy (NPWT) and artificial dermal replacement therapy after extensive surgical debridement and NPWT administration for severe complex wounds accompanied by tendon or bone exposure. However, flap surgery remains the only treatment for wounds in which the hardware is exposed after fracture fixation. Therefore, in this study, we attempted to prove the usefulness of the combined treatment using artificial dermal substitutes (MatriDerm) and NPWT by focusing on hardware-exposed wounds, which have not been studied before.

METHODS

From 2019 to 2021, we treated with our wound management procedure 14 patients with hardware-exposing wounds after internal fixation using plates, out of 48 patients with full-thickness posttraumatic skin defect. Before skin grafting, after surgical debridement and thorough washouts, MatriDerm was placed and NPWT was applied over it. This staged approach aimed at conditioning even the most complex wounds so that closure with MatriDerm-augmented skin grafting would become possible in a one-step approach.

RESULTS

We stratified the duration of treatment and number of replacements in NPWT according to the type of injury. Cases with open fractures required significantly longer NPWT than those with closed fractures (P = 0.01); however, there was no significant difference between the Gustilo-Anderson classification within open fractures (P > 0.05). Patients with open fractures underwent a mean of 6.6 changes while those with closed fractures underwent 2.5 (P = 0.002) until the final wound closure with MatriDerm-augmented skin grafting was performed. There was no significant difference in the treatment period based on the location and size of the wound, and there was no significant difference in the number of NPWT replacements. Skin grafting was successful in all 14 patients.

CONCLUSIONS

This study revealed that NPWT and artificial dermis-augmented skin grafting after combined treatment with NPWT and artificial dermis were sufficiently useful for hardware-exposed wounds, where flap surgery has been considered the only treatment to date.

Reconstruction of Achilles region defects: A single-centre experience

BACKGROUND

Reconstruction of Achilles tendon and the overlying tissue defects is a challenging undertaking. The spectrum of available repair methods range from secondary healing to the use of free flaps. The aim of this study was to discuss reconstruction options and to help the surgeon to select reliable approach to achieve favourable outcomes.

METHOD

In this study, we retrospectively evaluated 14 patients who underwent reconstruction of Achilles region defect between 2016 and 2019 at a single centre.

RESULTS

Reconstructions were performed with secondary healing (n = 2), negative pressure wound therapy and skin grafting (n = 2), free flaps (n = 6) and local and distant flaps (n = 4). Satisfactory aesthetic and functional outcomes were achieved in all patients. One patient developed partial skin graft loss. Marginal necrosis occurred in one of the local flaps. Wound dehiscence and flap retraction occurred in one of the free (superficial circumflex iliac artery perforator) flaps. One patient undergoing reconstruction with ulnar artery perforator flap developed intraoperative atrial fibrillation; the operation was terminated and reconstruction completed with skin grafting.

CONCLUSION

Orthoplastic reconstruction should be kept in mind for Achilles tendon defects. The use of special digital imaging techniques facilitates flap surgery and helps minimise the risk of flap complications. Conventional approaches are suitable for shallow small skin lesions. Local flaps are good options for deeper skin defects owing to superior aesthetic outcomes. Super-thin free flaps offer a distinct advantage in skillful hands. The use of multi-content free chimeric flaps for reconstruction of complex defects facilitates better anatomical repair. Cross leg or flow-through flaps may be considered in patients with compromised distal circulation. Selection of the most reliable approach for Achilles reconstruction is a key imperative to achieve favourable outcomes.

Urethral Tissue Reconstruction Using the Acellular Dermal Matrix Patch Modified with Collagen-Binding VEGF in Beagle Urethral Injury Models

Objectives

Urethral tissue reconstruction for hypospadias is challenging for urologists. In this study, bovine acellular dermal matrix (ADM) patch loading with collagen-binding vascular endothelial growth factor (CBD-VEGF) was used to repair the urethral injury in beagles.

Methods

The safety and effectiveness of the scaffold implantation were carefully evaluated by comparing among the urethral injury control group, ADM implantation group, and ADM modified with CBD-VEGF implantation group during 6 months. Urodynamic examination, urethral angiography, and pathological examination were performed to evaluate the recovery of urethral tissue.

Results

Stricture, urethral diverticulum, and increased urethral closure pressure were observed in the control group. Fistula was observed in one animal in the ADM group. By contrast, no related complications or other adverse situations were observed in animals treated with ADM patch modified with CBD-VEGF. The average urethra diameter was significantly smaller in the control animals than in scaffold implantation groups. Pathological examination revealed more distribution of proliferative blood vessels in the animals treated with ADM modified with CBD-VEGF.

Conclusions

Overall, ADM patches modified with CBD-VEGF demonstrated an optimized tissue repair performance in a way to increase tissue angiogenesis and maintain urethral function without inducing severe inflammation and scar formation.

The use of human acellular dermal matrices in advanced wound healing and surgical procedures: State of the art

Wound closure after post-traumatic injuries and/or localized at peculiar body sites (head-and-neck, oral cavity, legs) are particularly challenging and can often be delayed due to local and systemic factors. In case of deep wounds and/or hard-to-heal wounds, grafting of dermal acellular matrices (ADM) is often needed. Though a great variety of synthetic and semisynthetic dermal and skin equivalents are available, viable human dermis, is still considered the most physiological alternative to replace the loss of autologous dermis, by acting as a physiological scaffold that add structural support to soft tissues. To date, human ADMs (hADMs) have been employed in the reconstruction of skin defects affecting almost all body sites, ranging from visceral sites to the skin and subcutaneous tissues. This review aims to investigate the use of hADM at different body sites and their peculiar advantages. A literature search was using the search terms "acellular dermal matrices", "dermal regeneration", "advances wound healing", "human acellular dermal matrices surgery". A total of 50 out of 150 papers was included. Based on the current body if evidence, hADMs appear to bring several advantages, such as: protection of deep structures (eg, tendons, bones, cartilage and nerves); stimulation of a functional new dermis (rather than a scar); reduction of wound closure time; control of pain and exudate. Finally, hADMs may represent the best treatment option for hard-to-heal wound not only in terms of efficacy and patient satisfaction bout also in terms of sanitary costs, especially across Europe, where hADMs cannot be commercialized as medical devices.

A New Treatment for the Reconstruction of the Medial Compartment of the Ankle: The Combined Use of Biological Materials

Fractures, especially if articular and periarticular, are frequently associated to functional and clinical disabling outcomes and chronic pain. In particular, the injuries with loss of bone, ligament, and/or tendon tissue in which the full recovery of the wound area is not obtained are the worst anatomical/pathological conditions to heal. In this study, three different biological materials were used as regenerative approaches to rebuild the medial malleolus fracture of the ankle in which loss of bone, ligament, and tendon tissue occur. In particular, the morselized human bone tissue was combined with the human dermis decellularized, both augmented with homologous platelet-rich plasma. The magnetic resonance imaging study with contrast at the follow-up showed a signal compatible with vascularization of the tissue without sign of degeneration. Our new regenerative approach in which different biological materials were combined together showed a good choice of treatment for the reconstruction of not repairable outcome of a fracture.