Vascularized composite allotransplant in the realm of regenerative plastic surgery

Long-term outcomes and future challenges in face transplantation

Face transplant (FT) has emerged as a groundbreaking option for patients with severe facial deformities, resulting from congenital disorders, trauma, or tumor ablation. Although reconstructive surgery has made significant strides, the challenges of restoring both form and function remain, particularly in centrally located defects. This review explored the long-term outcomes of FT, addressing its challenges and potential pitfalls. A systematic review following the PRISMA guidelines was conducted, encompassing articles published in English from November 2005 to January 2023, which were searched across PubMed, MEDLINE, and EMBASE databases. Keywords included "face transplant," "face transplant outcomes," and "face transplant long-term." Data on surgical teams, patient demographics, transplant specifics, rejection episodes, additional surgeries, and patient-reported outcomes were extracted and analyzed. In total, 34 articles met the inclusion criteria. Over the 2 decades, 48 FT procedures were performed, with 23 patients followed for at least 3 years. Predominantly, patients were men (80%), averaging 31 years in age. Ballistic trauma (44.6%) and burns (25.5%) were common causes of injury. Chronic rejection emerged as a significant concern, leading to graft loss and necessitating retransplantation in 2 patients. Additional surgical procedures were often required. FT offers a remarkable solution for individuals with extensive facial disfigurement. Successful outcomes depend on factors, such as patient selection, multidisciplinary collaboration, psychiatric evaluation, and post-operative care. Nevertheless, challenges persist, including the need for lifelong immunosuppression and risk of chronic rejection. Although FT has transformed lives, continued success in this evolving field hinges on the ongoing research and vigilant patient management.

Immune modulation in transplant medicine: a comprehensive review of cell therapy applications and future directions

Balancing the immune response after solid organ transplantation (SOT) and vascularized composite allotransplantation (VCA) remains an ongoing clinical challenge. While immunosuppressants can effectively reduce acute rejection rates following transplant surgery, some patients still experience recurrent acute rejection episodes, which in turn may progress to chronic rejection. Furthermore, these immunosuppressive regimens are associated with an increased risk of malignancies and metabolic disorders. Despite significant advancements in the field, these IS related side effects persist as clinical hurdles, emphasizing the need for innovative therapeutic strategies to improve transplant survival and longevity. Cellular therapy, a novel therapeutic approach, has emerged as a potential pathway to promote immune tolerance while minimizing systemic side-effects of standard IS regiments. Various cell types, including chimeric antigen receptor T cells (CAR-T), mesenchymal stromal cells (MSCs), regulatory myeloid cells (RMCs) and regulatory T cells (Tregs), offer unique immunomodulatory properties that may help achieve improved outcomes in transplant patients. This review aims to elucidate the role of cellular therapies, particularly MSCs, T cells, Tregs, RMCs, macrophages, and dendritic cells in SOT and VCA. We explore the immunological features of each cell type, their capacity for immune regulation, and the prospective advantages and obstacles linked to their application in transplant patients. An in-depth outline of the current state of the technology may help SOT and VCA providers refine their perioperative treatment strategies while laying the foundation for further trials that investigate cellular therapeutics in transplantation surgery.

The Future of Microsurgery: Vascularized Composite Allotransplantation and Engineering Vascularized Tissue

Background

Microsurgical techniques have revolutionized the field of reconstructive surgery and are the mainstay for complex soft tissue reconstruction. However, their limitations have promoted the development of viable alternatives. This article seeks to explore technologies that have the potential of revolutionizing microsurgical reconstruction as it is currently known, reflect on current and future vascularized composite allotransplantation (VCA) practices, as well as describe the basic science within emerging technologies and their potential translational applications.

Methods

A literature review was performed of the technologies that may represent the future of microsurgery: vascularized tissue engineering (VCA) and flap-specific tissue engineering.

Results

VCA has shown great promise and has already been employed in the clinical setting (especially in face and limb transplantation). Immunosuppression, logistics, cost, and regulatory pathways remain barriers to overcome to make it freely available. Vascularized and flap-specific tissue engineering remain a laboratory reality but have the potential to supersede VCA. The capability of creating an off-the-shelf free flap matching the required tissue, size, and shape is a significant advantage. However, these technologies are still at the early stage and require significant advancement before they can be translated into the clinical setting.

Conclusion

VCA, vascularized tissue engineering, and flap-specific bioengineering represent possible avenues for the evolution of current microsurgical techniques. The next decade will elucidate which of these three strategies will evolve into a tangible translational option and hopefully bring a paradigm shift of reconstructive surgery.

Maximizing Solid Organ and Face Transplant Procurement Team Coordination: The Posterior Tibial Artery Flap as an Ideal Sentinel Flap

Face transplantation became a reality with the first case performed in 2005. Facial tissue allograft procurement is technically complex and time-intensive. Brain-dead deceased donors are frequently, if not always, multiorgan donors. Every effort should be made during face allograft recovery to minimize any risk to the recovery of lifesaving solid organs. Some programs require the procurement of a myofascial vascularized skin graft to function as a sentinel flap allowing frequent monitoring for rejection without negatively impacting the esthetics of the face graft. Up till now, the flap used has been the radial forearm flap. Procuring the radial forearm flap places the procuring team in close proximity to the head and torso, where the face recovery and the solid organ recovery teams would require unhindered access. Here, we present the posterior tibial artery flap as an alternative flap that would provide benefits to the coordination of the multiple teams working to procure organs from a deceased donor.

Hand Transplantation-Risks and Benefits

Composite tissue allotransplantation (CTA) is the culmination of progress in transplantation, allowing the reconstruction of the hand in amputees. Worldwide, more than 100 procedures have been performed. The aim of this work was to understand the hand allotransplantation approach, making known current aspects, risks, and benefits. A PubMed research was realized between October 2018 and March 2019, including terms like "Hand transplantation" AND "Composite tissue allotransplantation," "Hand transplantation" AND "Functional outcomes," "Hand transplantation" AND "Immunosuppression," "Hand prosthetics," "Hand Transplantation" AND "Ethics." There were included papers between 1995 and 2018, with English language, amputee human adults, systematic reviews, and clinical studies. Seventy-two papers were fully evaluated. There are technical aspects that influence the procedure like team coordination or surgical technique. It requires a long-life treatment, which has risks such as toxicity or infections. However, it allows the recovery of fine movements, and independence, to perform detailed tasks. The indications must be carefully considered, because some patients benefit from the use of prosthesis. CTA has become an option for amputees so it is important to do more research, to determine the benefits of this procedure. It is not considered a life-saving procedure, so there is an ethical debate because of the risks.

Engineering Vascularized Composite Allografts Using Natural Scaffolds: A Systematic Review

INTRODUCTION

Vascularized Composite Allotransplantation refers to the transplantation of multiple tissues as a functional unit from a deceased donor to a recipient with a severe injury. These grafts serve as potential replacements for traumatic tissue losses. The main problems are the consequences of the long immunosuppressive drugs medications and the lake of compatible donor. To avoid these limitations, decellularization/recellularization constitute an attractive approach. The aim of decellularization/recellularization technology is to develop immunogenic free biological substitutes that will restore, maintain, or improve tissue and organ's function.

METHODS

A PubMed search was performed for articles on decellularization and recellularization of composite tissue allografts between March and February 2021, with no restrictions in publication year. The selected reports were evaluated in terms of decellularization protocols, assessment of decellularized grafts, and evaluation of their biocompatibility and repopulation with cells both in vitro and in vivo.

RESULTS

The search resulted in a total of 88 articles. Each article was reviewed, 77 were excluded and the remaining 11 articles reported decellularization of 12 different vascular composite allografts in humans (four), large animals (three), and small animals (rodents) (five). The decellularization protocol for vascularized composite allotransplantation varies slightly between studies, but majority of the reports employ 1% sodium dodecyl sulfate as the main reagent for decellularization. The immunological response of the decellularized scaffolds remains poorly evaluated. Few authors have been able to attempt the recellularization and transplantation of these scaffolds. Successful transplantation seems to require prior recellularization.

CONCLUSION

Decellularization/recellularization is a promising, growing, emerging developing research field in vascular composite allotransplantation.

Public Perceptions of Cross-Sex Vascularized Composite Allotransplantation

BACKGROUND

Cross-sex vascularized composite allotransplantation has been performed in cadaveric facial transplantation and clinical extremity transplantation. Understanding the challenge of appropriate donor-recipient matching, this study sought to characterize the public's perception of cross-sex vascularized composite allotransplantation.

METHODS

Participants were surveyed in New York City. Data collected included demographics and willingness to donate vascularized composite allografts (VCAs) of various types. Similar questions were asked in the context of same-sex and cross-sex donation.

RESULTS

A total of 101 participants (male: 56.4%; age ≤35 years: 62.4%) were surveyed. The majority expressed willingness to donate to recipients of a different sex (hand: 78.2%, face: 56.4%, penis or uterus: 69.3%, lower limb: 81.2%, abdominal wall: 80.2%, larynx: 81.2%, and solid organs: 85.2%). Among VCAs, willingness to donate facial allografts was significantly different in same-sex versus cross-sex contexts (64.4% vs 56.4%; P = 0.008). Participants were also significantly more likely to donate VCAs to same-sex recipients on behalf of themselves versus loved ones (P < 0.05). There was significantly lower willingness to receive cross-sex versus same-sex facial (P = 0.022) and genital allografts (P = 0.022). Education on the preservation of recipient masculinity or femininity in cross-sex facial transplantation increased participants' willingness to receive a cross-sex face transplant from 56.4% to 71.3% (P = 0.001).

CONCLUSIONS

This study highlights the urban public's acceptance of VCA donation or reception regardless of sex mismatch. There is increased willingness to receive a cross-sex face transplant after education, highlighting opportunities for future focused interventions to increase public awareness and ultimately the donor pool.

Penile allotransplantation: early outcomes from reported cases and survivorship considerations

Vascular composite allografts are at the forefront of medical and surgical innovation. With this new technique and the ability to transplant a face, hands, an abdominal wall, a uterus, or even a penis, patients can undergo operations that may drastically improve their quality of life. Although this process presents significant opportunities it is not always an easy road and requires significant upfront counseling and life-long immunosuppression. Often the recovery course is long, with functionality taking months to years to gain. Immunosuppression must be used to prevent rejection of the allograft although it has serious long-term side-effects. Only five patients have undergone penile allotransplantation but reported outcomes from these small numbers have nonetheless offered significant lessons with each patient. While the operation is still in its infancy, it is certain that shared experiences by surgical teams will yield improved outcomes in the future.

Innovations and Future Directions in Head and Neck Microsurgical Reconstruction

Head and neck reconstructive microsurgery is constantly innovating because of a combination of multidisciplinary advances. This article examines recent innovations that have affected the field as well as presenting research leading to future advancement. Innovations include the use of virtual surgical planning and three-dimensional printing in craniofacial reconstruction, advances in intraoperative navigation and imaging, as well as postoperative monitoring, development of minimally invasive reconstructive microsurgery techniques, integration of regenerative medicine and stem cell biology with reconstruction, and the dramatic advancement of face transplant.

Cellular Based Strategies for Microvascular Engineering

Vascularization is a major hurdle in complex tissue and organ engineering. Tissues greater than 200 μm in diameter cannot rely on simple diffusion to obtain nutrients and remove waste. Therefore, an integrated vascular network is required for clinical translation of engineered tissues. Microvessels have been described as <150 μm in diameter, but clinically they are defined as <1 mm. With new advances in super microsurgery, vessels less than 1 mm can be anastomosed to the recipient circulation. However, this technical advancement still relies on the creation of a stable engineered microcirculation that is amenable to surgical manipulation and is readily perfusable. Microvascular engineering lays on the crossroads of microfabrication, microfluidics, and tissue engineering strategies that utilize various cellular constituents. Early research focused on vascularization by co-culture and cellular interactions, with the addition of angiogenic growth factors to promote vascular growth. Since then, multiple strategies have been utilized taking advantage of innovations in additive manufacturing, biomaterials, and cell biology. However, the anatomy and dynamics of native blood vessels has not been consistently replicated. Inconsistent results can be partially attributed to cell sourcing which remains an enigma for microvascular engineering. Variations of endothelial cells, endothelial progenitor cells, and stem cells have all been used for microvascular network fabrication along with various mural cells. As each source offers advantages and disadvantages, there continues to be a lack of consensus. Furthermore, discord may be attributed to incomplete understanding about cell isolation and characterization without considering the microvascular architecture of the desired tissue/organ.

Attitudes of Hand Surgeons and Hand Reconstruction Patients Toward Hand Allotransplantation in Taiwan

BACKGROUND

Recent advances in immunosuppressive protocols have increasingly made hand allotransplantation a realistic reconstructive option with more than 100 cases performed worldwide. While attitudes toward allotransplantation have been assessed for North American surgeons and patients alike, similar assessments have previously remained unconducted in Asia in general and Taiwan in specific. This study examines the perceptions of both Taiwanese hand surgeons and hand reconstruction patients.

METHODS

An email-based survey was sent to all active members of the Taiwanese Society for Surgery of the Hand. Surgeon training backgrounds and practice profiles were gathered as well as current beliefs on indications, risks, ethicality, priority of psychosocial issues, and obstacles to implementation. Patients receiving rehabilitation at Chang Gung Memorial Hospital Linkou after severe upper extremity injuries were invited to complete a patient survey. Demographics, injury characteristics, understanding of allotransplantation and immunosuppression, willingness to donate, and willingness to receive transplantation were assessed.

RESULTS

Forty-four hand surgeons responded (24.3% response rate). The majority (61.4%) considered hand allotransplantation to be a high-risk operation, although 40% supported the development of hand allotransplantation under current techniques and immunosuppression. Bilateral hands loss was the most commonly accepted indication for transplant (90.9%), whereas dominant hand loss was less frequently accepted (43.2%). Treatment compliance and functional outcomes were the most frequent psychosocial issues of concern regarding patient counseling. Patient respondents were mostly in the fifth decade of life (29.5%) with at least a high school education (75.0%). Most were aware of the feasibility of hand transplantation (68.2%). Patients were more likely than surgeons to consider nondominant hand, multiple-digit, and thumb-only amputations as indications for transplantation. Functional outcomes and financial considerations were the most frequent patient concerns.

CONCLUSIONS

This study indicates there is support for hand allotransplantation as a solution for limb loss in both hand surgeons and hand patients in Taiwan. This study adds to the lack of knowledge regarding surgeon and patient attitudes toward allotransplantation in Asia, although further work is required to assess the willingness of broader Taiwanese medical to refer candidates and for the general population to donate.

Face transplantation for the blind: more than being blind in a sighted world

Face transplantation (FT) is a landmark in reconstructive surgery involving vascularised composite allotransplantation. A recent issue of FT for patients who are blind has arisen. Some bioethicists recommend not excluding a patient who is blind, as this may amount to discrimination. From an ethical standpoint, FT for those with blindness is appropriate in selected candidates. This article seeks to add to the clinical evidence supporting FT for those with blindness by detailing a complementary psychosocial perspective. Currently, there is little relevant research about the subjectivity of the blind. This is critical since the arguments against FT for the blind refer to their inability to see their face and to view the reaction of others to their disfigured faces. We begin with a brief look at examples of FT involving blindness and associated arguments. The next part is a multidisciplinary investigation of the experiences of the blind. These are gleaned from a close reading of the literature and drawing inferences, as direct studies are rare. The discussion analyses identity themes of the blind in relation to their faces: as they experience it; the face they wish to show to the world; and how others perceive and react to their face in a saturated environment of imagery and visual communication. Disability and the blind person's experience of faces are well-founded considerations for medical practitioners and ethics boards in the process of FT decision-making.

Hand Transplantation: Current concepts and management algorithm

Introducción. El trasplante de mano ha sido uno de los retos del siglo XXI, cuyo primer caso reportado ocurrió en 1964. En este campo se han hecho estudios y avances que permitieron explorar nuevas alternativas para el manejo del paciente con trasplante de mano, por lo que diversos centros de referencia han realizado análisis basados en sus experiencias, las cuales permitieron lograr la viabilidad de este tipo de trasplante.Objetivo. Esta revisión busca dar una visión general sobre el trasplante de mano y proponer un algoritmo de manejo.Materiales y métodos. La selección de candidatos requiere una serie de criterios, tales como evaluación clínica, paraclínica y psicosocial, desarrollados por un equipo multidisciplinario. La inmunosupresión busca evitar el rechazo y los inmunosupresores deben tener los niveles séricos apropiados para reducir sus efectos adversos. Se han reportado casos de rechazo agudo clásico y atípico, donde la piel es el principal tejido blanco, y rechazo crónico, en el cual se afectan los vasos sanguíneos. El seguimiento se realiza con varias pruebas, de modo que la de oro es la biopsia de piel.Resultados. Las complicaciones del tratamiento farmacológico derivan de la toxicidad de los medicamentos y se manifiestan como alteraciones metabólicas, infecciones oportunistas y neoplasias. La rehabilitación y los aspectos sociales, como el grado de satisfacción del paciente, deben ser evaluados durante la recuperación para asegurar adherencia al tratamiento. En 2011 el registro internacional de alotransplante compuesto de mano reportó 39 casos de trasplante de extremidades superiores con resultados variables; todo esto evidencia que para lograr un resultado óptimo y viable del trasplante debe realizarse seguimiento por un equipo multidisciplinario, red de apoyo del paciente y motivación del mismo, junto con el cumplimiento del manejo farmacológico.Conclusión. Se espera que nuevas investigaciones puedan crear estrategias para desarrollar tolerancia y, de esta forma, reducir el manejo mediante inmunosupresión.

Public's Knowledge and Attitudes Toward Vascularized Composite Allotransplantation and Donation

BACKGROUND

The purpose of this survey was to assess the public's knowledge and attitudes toward vascularized composite allotransplantation and donation.

METHODS

Members of the public (n = 5942) were surveyed using a questionnaire that examined their knowledge and attitudes concerning solid organs (kidney, heart, liver, lung, and pancreas) and vascularized composite tissue (hand/upper extremity, lower extremity, abdominal wall, and face) transplantations and donations.

RESULTS

Respondents demonstrated greater (all P < 0.05) knowledge and willingness to donate and/or receive solid organs than vascularized composite tissues. Educational level, accurate knowledge, willingness to donate, and willingness to receive were significant (all P < 0.05) determinants of acceptance to donate and/or receive hand/upper extremity, lower extremity, face, and/or abdominal wall.

CONCLUSION

The public presented less knowledge and willingness to donate and/or receive hand/upper extremity, lower extremity, abdominal wall, and face.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Regenerative Medicine Build-Out

Regenerative technologies strive to boost innate repair processes and restitute normative impact. Deployment of regenerative principles into practice is poised to usher in a new era in health care, driving radical innovation in patient management to address the needs of an aging population challenged by escalating chronic diseases. There is urgency to design, execute, and validate viable paradigms for translating and implementing the science of regenerative medicine into tangible health benefits that provide value to stakeholders. A regenerative medicine model of care would entail scalable production and standardized application of clinical grade biotherapies supported by comprehensive supply chain capabilities that integrate sourcing and manufacturing with care delivery. Mayo Clinic has rolled out a blueprint for discovery, translation, and application of regenerative medicine therapies for accelerated adoption into the standard of care. To establish regenerative medical and surgical service lines, the Mayo Clinic model incorporates patient access, enabling platforms and delivery. Access is coordinated through a designated portal, the Regenerative Medicine Consult Service, serving to facilitate patient/provider education, procurement of biomaterials, referral to specialty services, and/or regenerative interventions, often in clinical trials. Platforms include the Regenerative Medicine Biotrust and Good Manufacturing Practice facilities for manufacture of clinical grade products for cell-based, acellular, and/or biomaterial applications. Care delivery leverages dedicated interventional suites for provision of regenerative services. Performance is tracked using a scorecard system to inform decision making. The Mayo Clinic roadmap exemplifies an integrated organization in the discovery, development, and delivery of regenerative medicine within a growing community of practice at the core of modern health care.

SIGNIFICANCE

Regenerative medicine is at the vanguard of health care poised to offer solutions for many of today's incurable diseases. Accordingly, there is a pressing need to develop, deploy, and demonstrate a viable framework for rollout of a regenerative medicine model of care. Translation of regenerative medicine principles into practice is feasible, yet clinical validity and utility must be established to ensure approval and adoption. Standardized and scaled-up regenerative products and services across medical and surgical specialties must in turn achieve a value-added proposition, advancing intended outcome beyond current management strategies.

Virtual surgical planning in craniofacial surgery

The complex three-dimensional anatomy of the craniofacial skeleton creates a formidable challenge for surgical reconstruction. Advances in computer-aided design and computer-aided manufacturing technology have created increasing applications for virtual surgical planning in craniofacial surgery, such as preoperative planning, fabrication of cutting guides, and stereolithographic models and fabrication of custom implants. In this review, the authors describe current and evolving uses of virtual surgical planning in craniofacial surgery.