Bilateral transfemoral lower extremity transplantation: result at 1 year

A World Update of Progress in Lower Extremity Transplantation: What's Hot and What's Not

ABSTRACT

The field of vascularized composite allotransplantation (VCA) is the new frontier of solid organ transplantation (SOT). VCA spans life-enhancing/life-changing procedures such as upper extremity, craniofacial (including eye), laryngeal, tracheal, abdominal wall, penis, and lower extremity transplants. VCAs such as uterus transplants are life giving unlike any other SOT. Of all VCAs that have shown successful intermediate- to long-term graft survival with functional and immunologic outcomes, lower extremity VCAs have remained largely underexplored. Lower extremity transplantation (LET) can offer patients with improved function compared to the use of conventional prostheses, reducing concerns of phantom limb pain and stump complications, and offer an option for eligible amputees that either fail prosthetic rehabilitation or do not adapt to prosthetics. Nevertheless, these benefits must be carefully weighed against the risks of VCA, which are not trivial, including the adverse effects of lifelong immunosuppression, extremely challenging perioperative care, and delayed nerve regeneration. There have been 5 lower extremity transplants to date, ranging from unilateral or bilateral to quadrimembral, progressively increasing in risk that resulted in fatalities in 3 of the 5 cases, emphasizing the inherent risks. The advantages of LET over prosthetics must be carefully weighed, demanding rigorous candidate selection for optimal outcomes.

Immunologic Outcomes in Cross-Sex Solid Organ Transplants: A Systematic Review and Meta-Analysis to Inform Vascularized Composite Allotransplantation

BACKGROUND

Of nearly 90 hand and 50 face transplant recipients, only five have received a cross-sex vascularized composite allotransplantation (CS-VCA). CS-VCA has the potential to expand the donor pool and has been proven anatomically feasible and ethically acceptable in previous studies. However, there is a lack of immunologic data. This study evaluated the immunologic feasibility of CS-VCA through analysis of the solid organ transplant literature, given the paucity of CS-VCA data. The authors hypothesize that rates of acute rejection (AR) and graft survival (GS) in CS versus same-sex (SS) solid organ transplantation are similar.

METHODS

A systematic review and meta-analysis were performed. Studies comparing GS or AR episodes in CS and SS adult kidney (KT) and liver transplant (LT) populations were included. Odds ratios were calculated for overall GS and AR for all SS and CS transplant combinations [male-to-female (MTF), female-to-male, and overall].

RESULTS

A total of 693 articles were initially identified with 25 included in the meta-analysis. No significant difference in GS was noted between SS-KT versus CS-KT [OR, 1.04 (95% CI, 1.00 to 1.07); P = 0.07), SS-KT versus MTF-KT [OR, 0.97 (95% CI, 0.90 to 1.04); P = 0.41), and SS-LT versus MTF-LT [OR, 0.95 (95% CI, 0.91 to 1.00); P = 0.05). No significant difference in AR was noted between SS-KT versus MTF-KT [OR, 0.99 (95% CI, 0.96 to 1.02); P = 0.57), SS-LT versus CS-LT [OR, 0.78 (95% CI, 0.53 to 1.16); P = 0.22], or SS-LT versus female-to-male LT [OR, 1.03 (95% CI, 0.95 to 1.12); P = 0.47]. For the remaining pairings, GS was significantly increased and AR was significantly decreased in the SS transplants.

CONCLUSIONS

Published data suggest immunologic feasibility of CS-KT and CS-LT with the potential for generalization to the VCA population.

CLINICAL RELEVANCE STATEMENT

In theory, CS-VCA could expand the potential donor pool, ultimately leading to decreased wait times for recipients and improve the likelihood of establishing a immunologically favorable donor-recipient match.

Bionic Prostheses: The Emerging Alternative to Vascularised Composite Allotransplantation of the Limb

Twenty years have surpassed since the first vascularised composite allotransplantation (VCA) of the upper limb. This is an opportunity to reflect on the position of VCA as the gold standard in limb reconstruction. The paucity of recipients, tentative clinical outcomes, and insufficient scientific progress question whether VCA will remain a viable treatment option for the growing numbers of amputees. Bionic technology is advancing at a rapid pace. The prospect of widely available, affordable, safely applied prostheses with long-standing functional benefit is appealing. Progress in the field stems from the contributions made by engineering, electronic, computing and material science research groups. This review will address the ongoing reservations surrounding VCA whilst acknowledging the future impact of bionic technology as a realistic alternative for limb reconstruction.

Addressing common orthopaedic calamities with microsurgical solutions

Reconstructive microsurgery has been an essential aspect of orthopaedic surgery and extremity reconstruction since the introduction of the operating microscope in the mid-20^th century. The reconstructive ladder ranges from simple healing by secondary intention to complex procedures such as free tissue transfer and vascularized composite allotransplantation. As orthopaedic surgery has evolved over the past 60 years, so too have the reconstructive microsurgical skills that are often needed to address common orthopaedic surgery problems. In this article, we will discuss a variety of complex orthopaedic surgery scenarios ranging from trauma to infection to tumor resection as well as the spectrum of microsurgical solutions that can aid in their management.

The 2020 Facial Transplantation Update: A 15-Year Compendium

Over the past 15 years, landmark achievements have established facial transplantation (FT) as a feasible reconstructive option for otherwise irreparable craniofacial defects. However, as the field matures and long-term outcomes begin to emerge, FT teams around the world are now facing new challenges. Data for this review were identified by searches of the PubMed/MEDLINE database from inception through August 2020. All English-language articles pertaining to FT were included. Significant advances in candidate selection, technology, operative technique, posttransplant care, and immunosuppressive management have contributed to the tremendous expansion of the field, culminating in the execution in the past 3 years of 2 facial re-transplantations, and most recently the world’s first successful combined face and double hand transplant in August 2020. Despite these achievements, the allograft donor pool remains limited, with long wait times, requiring surgical experimentation with cross-sex FT. Immunosuppressive management has improved, but significant adverse events continue to be reported. Most recently, the COVID-19 pandemic has placed an unprecedented strain on the healthcare system, with various implications for the practice of reconstructive transplantation. In this article, we provide the most comprehensive and up-to-date FT review, highlighting fundamental lessons learned and recent advancements, while looking toward the challenges ahead. Over the past 15 years, extensive multidisciplinary efforts have been instrumental to the establishment of FT as a feasible reconstructive option. As novel challenges are beginning to emerge, continued collaborative and multispecialty research efforts are needed to further this field.

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.

Equity in access to facial transplantation

We examine ethical considerations in access to facial transplantation (FT), with implications for promoting health equity. As a form of vascularised composite allotransplantation, FT is still considered innovative with a relatively low volume of procedures performed to date by a small number of active FT programmes worldwide. However, as numbers continue to increase and institutions look to establish new FT programmes, we anticipate that attention will shift from feasibility towards ensuring the benefits of FT are equitably available to those in need. This manuscript assesses barriers to care and their ethical implications across a number of considerations, with the intent of mapping various factors relating to health equity and fair access to FT. Evidence is drawn from an evolving clinical experience as well as published scholarship addressing several dimensions of access to FT. We also explore novel concerns that have yet to be mentioned in the literature.

Feasibility and Perception of Cross-sex Face Transplantation to Expand the Donor Pool

Background:

A major challenge in face transplantation (FT) is the limited donor allograft pool. This study aimed to investigate the feasibility of cross-sex FT (CSFT) for donor pool expansion by: (1) comparing craniomaxillofacial metrics following CSFT versus same-sex FT (SSFT); and (2) evaluating the public and medical professionals’ perception of CSFT.

Methods:

Seven cadaveric FTs were performed, resulting in both CSFT and SSFT. Precision of bony and soft tissue inset was evaluated by comparing pre- versus post-operative cephalometric and anthropometric measurements. Fidelity of the FT compared to the virtual plan was assessed by imaging overlay techniques. Surveys were administered to medical professionals, medical students, and general population to evaluate opinions regarding CSFT.

Results:

Five CSFTs and 2 SSFTs were performed. Comparison of recipients versus post-transplant outcomes showed that only the bigonial and medial intercanthal distances were statistically different between CSFT and SSFT (P = 0.012 and P = 0.010, respectively). Of the 213 survey participants, more were willing to donate for and undergo SSFT, compared with CSFT (donate: 59.6% versus 53.0%, P = 0.001; receive: 79.5% versus 52.3%, P < 0.001). If supported by research, willingness to receive a CSFT significantly increased to 65.6% (P < 0.001). On non-blinded and blinded assessments, 62.9% and 79% of responses rated the CSFT superior or equal to SSFT, respectively.

Conclusions:

Our study demonstrates similar anthropometric and cephalometric outcomes for CSFT and SSFT. Participants were more reticent to undergo CSFT, with increased willingness if supported by research. CSFT may represent a viable option for expansion of the donor pool in future patients prepared to undergo transplantation.

Applied Bioengineering in Tissue Reconstruction, Replacement, and Regeneration

IMPACT STATEMENT

The use of autologous tissue in the reconstruction of tissue defects has been the gold standard. However, current standards still face many limitations and complications. Improving patient outcomes and quality of life by addressing these barriers remain imperative. This article provides historical perspective, covers the major limitations of current standards of care, and reviews recent advances and future prospects in applied bioengineering in the context of tissue reconstruction, replacement, and regeneration.

Emerging Ethical Challenges Raised by the Evolution of Vascularized Composite Allotransplantation

BACKGROUND

Despite early skepticism, the field of vascularized composite allotransplantation (VCA) has demonstrated feasibility. The ethics of VCA have moved past doubts about the morality of attempting such transplants to how to conduct them ethically.

METHODS

Leaders of each program performing and/or evaluating VCA in the United States were invited to participate in a working group to assess the state and future of VCA ethics and policy. Four meetings were held over the course of 1 year to describe key challenges and potential solutions.

RESULTS

Working group participants concluded that VCA holds great promise as treatment for patients with particular injuries or deficits, but the field faces unique challenges to adoption as standard of care, which can only be overcome by data sharing and standardization of evaluation and outcome metrics.

CONCLUSIONS

Adequate attention must be given to concerns including managing the uniquely intense physician-patient relationship, ethical patient selection, ensuring patients have adequate representation, informing and earning the trust of the public for donation, standardizing metrics for success, and fostering an environment of data sharing. These steps are critical to transitioning VCA from research to standard of care and to its insurance coverage inclusion.

Ethicists' Opinions Regarding the Permissibility of Face Transplant

BACKGROUND

Face transplantation can offer functional and aesthetic restoration to patients who have exhausted their reconstructive options, improving quality of life and psychosocial integration. Ethical issues in face transplantation abound, including questions of patient selection and evaluation before transplantation. To date, there has been no study of ethicists' opinions regarding face transplantation.

METHODS

An online survey of attendees of the 2015 International Conference on Clinical Ethics Consultation (n = 401) assessed ethicists' opinions about face transplantation. Questions examined the risk-to-benefit ratio of immunosuppression; permissibility of face transplantation in subpopulations (including children and blind patients); donor-recipient age, sex, and ethnicity mismatches; and ethical oversight.

RESULTS

Most ethicists (84 percent) agreed that it is permissible to perform a face transplantation on an adult in the absence of clear medical contraindications. Most respondents also agreed that it is permissible to perform a face transplantation on a child (62 percent) or a blind patient (61 percent), yet demonstrated less consensus regarding the permissibility of performing a face transplantation on patients with an increased risk of immune rejection. Respondents were generally supportive of age, sex, and ethnicity mismatches, with 43 percent indicating that it is permissible to have a sex mismatch. The majority answered that face transplantation should be covered by federal insurance (74 percent).

CONCLUSIONS

This study provides insight into clinical ethicists' views regarding face transplantation. Most ethicists support the ethical permissibility of face transplantation, and did not have concerns about age, sex, and ethnicity mismatches. These findings highlight emerging areas of consensus regarding the ethical permissibility of face transplantation.

A Call to Accountability: Reporting Outcomes in Vascularized Composite Allotransplantation

Because nearly all the vascularized composite allotransplants performed in the United States have been proposed and carried out as research, the ethical duty to report outcomes pertains. This duty is set forth in several international statements, including the World Health Organization’s Statement on Public Disclosure of Clinical Trial Results, the 2013 Helsinki Declaration, and the Singapore Statement on Research Integrity. These international statements call for the reporting of negative and inconclusive outcomes as well as positive outcomes, and for the reporting of results from previously unreported past research. In 2014, the Organ Procurement and Transplant Network vascularized composite allotransplant committee proposed mandatory data collection and submission requirements for transplants, but only for those which took place in September 2015 or later. Reporting of data for the allotransplants which took place before September 2015 was regarded as optional, even though the pre-September 2015 transplants represent the majority of vascularized composite allotransplants in the United States and all the long-term outcome data. We encourage the American Society of Reconstructive Transplantation and the Organ Procurement and Transplant Network committee to embrace the international ethical standards and to hold all vascularized composite allotransplant programs in the United States accountable for reporting data on outcomes of pre-September 2015 transplants.

Impact of Melatonin in Solid Organ Transplantation-Is It Time for Clinical Trials? A Comprehensive Review

Solid organ transplantation is the "gold standard" for patients with end-stage organ disease. However, the supply of donor organs is critical, with an increased organ shortage over the last few years resulting in a significant mortality of patients on waiting lists. New strategies to overcome the shortage of organs are urgently needed. Some experimental studies focus on melatonin to improve the donor pool and to protect the graft; however, current research has not reached the clinical level. Therefore, this review provides a comprehensive overview of the data available, indicating that clinical evaluation is warranted.

Prevalence and Distribution of Potential Vascularized Composite Allotransplant Donors, Implications for Optimizing the Donor-recipient Match

BACKGROUND

Vascularized composite allotransplantation (VCA) is an emerging and growing field. Little is known about the prevalence and distribution of the adult potential donor population in the United States now that it falls under the oversight of the United Network for Organ Sharing (UNOS).

METHODS

We assessed the UNOS database from 2008 to 2015 to estimate the prevalence and distribution of adult potential vascularized composite allograft donors. Donor inclusion and exclusion criteria were developed in a way to minimize risk to recipients and were applied to the dataset. Donors were categorized by factors that influence vascularized composite allograft matching including ABO blood type, cytomegalovirus status, and ethnicity (correlate for skin color) and sorted by UNOS region.

RESULTS

Just under half of all brain dead donors met the inclusion/exclusion criteria. Blood type O, cytomegalovirus+, White donors represented the most frequent donor profile while blood type AB, cytomegalovirus-, Asian donors were the least common. UNOS region 3 had the most and region 1 had the least potential VCA donors per year. Nearly all potential VCA donors were solid organ donors with the liver being the most commonly donated solid organ in this population.

CONCLUSIONS

A large portion of the solid organ donor pool would qualify as adult vascularized composite allograft donors in the current UNOS system. These data will assist transplant teams in determining the prevalence and distribution of vascularized composite allograft donors for their individual patients awaiting composite allografts based on relevant matching characteristics in addition to standard transplant criteria.

The Effect of MHC Antigen Matching Between Donors and Recipients on Skin Tolerance of Vascularized Composite Allografts

The emergence of skin-containing vascularized composite allografts (VCAs) has provided impetus to understand factors affecting rejection and tolerance of skin. VCA tolerance can be established in miniature swine across haploidentical MHC barriers using mixed chimerism. Because the deceased donor pool for VCAs does not permit MHC antigen matching, clinical VCAs are transplanted across varying MHC disparities. We investigated whether sharing of MHC class I or II antigens between donors and recipients influences VCA skin tolerance. Miniature swine were conditioned nonmyeloablatively and received hematopoietic stem cell transplants and VCAs across MHC class I (n = 3) or class II (n = 3) barriers. In vitro immune responsiveness was assessed, and VCA skin-resident leukocytes were characterized by flow cytometry. Stable mixed chimerism was established in all animals. MHC class II-mismatched chimeras were tolerant of VCAs. MHC class I-mismatched animals, however, rejected VCA skin, characterized by infiltration of recipient-type CD8⁺ lymphocytes. Systemic donor-specific nonresponsiveness was maintained, including after VCA rejection. This study shows that MHC antigen matching influences VCA skin rejection and suggests that local regulation of immune tolerance is critical in long-term acceptance of all VCA components. These results help elucidate novel mechanisms underlying skin tolerance and identify clinically relevant VCA tolerance strategies.

Primary Central Nervous System Posttransplant Lymphoproliferative Disease in a Bilateral Transfemoral Lower Extremity Transplantation Recipient

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous group of clinical and pathological entities characterized by malignant lymphoid cell proliferation occurring after solid organ transplantation, with frequent extranodal involvement. Central nervous system (CNS) involvement occurs in 7-15% of the cases and it is a significant negative prognostic factor. A case of primary CNS (PCNS) PTLD in the first bilateral lower limb transplant recipient is presented.

Vascularized composite allotransplant in the realm of regenerative plastic surgery

Vascularized composite allotransplant (VCA) has led to new treatment options for patients with severe upper extremity and facial injuries. Although VCA can restore form and function, it exposes the patient to the risks associated with lifelong immunosuppression. Hopefully, ongoing advances in regenerative medicine will someday obviate the need for VCA, but until that time, VCA remains an immediate means of reconstructing otherwise unreconstructable defects. We review the outcomes of hand and face transplants, as well as the recent developments in immunosuppression as it relates to the field of VCA.

Overcoming cross-gender differences and challenges in Le Fort-based, craniomaxillofacial transplantation with enhanced computer-assisted technology

BACKGROUND

Sex-specific anthropometrics, skin texture/adnexae mismatch, and social apprehension have prevented cross-gender facial transplantation from evolving. However, the scarce donor pool and extreme waitlist times are currently suboptimal. Our objective was to (1) perform and assess cadaveric facial transplantation for each sex-mismatched scenario using virtual planning with cutting guide fabrication and (2) review the advantages/disadvantages of cross-gender facial transplantation.

METHODS

Cross-gender facial transplantation feasibility was evaluated through 2 mock, double-jaw, Le Fort-based cadaveric allotransplants, including female donor-to-male recipient and male donor-to-female recipient. Hybrid facial-skeletal relationships were investigated using cephalometric measurements, including sellion-nasion-A point and sellion-nasion-B point angles, and lower-anterior-facial-height to total-anterior-facial-height ratio. Donor and recipient cutting guides were designed with virtual planning based on our team's experience in swine dissections and used to optimize the results.

RESULTS

Skeletal proportions and facial-aesthetic harmony of the transplants (n = 2) were found to be equivalent to all reported experimental/clinical sex-matched cases by using custom guides and Mimics technology. Cephalometric measurements relative to Eastman Normal Values are shown.

CONCLUSIONS

On the basis of our results, we believe that cross-gender facial transplantation can offer equivalent, anatomical skeletal outcomes to those of sex-matched pairs using preoperative planning and custom guides for execution. Lack of literature discussion of cross-gender facial transplantation highlights the general stigmata encompassing the subject. We hypothesize that concerns over sex-specific anthropometrics, skin texture/adnexae disparity, and increased immunological resistance have prevented full acceptance thus far. Advantages include an increased donor pool with expedited reconstruction, as well as size-matched donors.

Current status of vascularized composite tissue allotransplantation

Vascularized composite tissue allotransplantation (VCA) offers treatment options of complex functional deficiencies that cannot be repaired with conventional reconstructive methods. VCAs consist of blocks of functional units comprising different tissue types such as skin, bone, muscle, nerves, blood vessels, tendons, ligaments and others, and are thus substantially different from the composition of organ transplants. The field of VCA has made fascinating progresses in the recent past. Among other VCAs, numerous successful hand, face and limb transplants have been performed in the world. At the same time, specific questions in regard to innate and adaptive immunity, consequences of ischemia/reperfusion injury, immunosuppression, preservation, and regenerative capacity remain. In spite of this, the field is poised to make significant advances in the near future.

The advent of the restorative plastic surgeon

Plastic surgery is presently typified by the existence of discrete clinical identities, namely that of the cosmetic plastic surgeon and the reconstructive plastic surgeon. The emergence of vascularized composite allotransplantation has been accompanied by the development of a third distinct clinical identity, that of the restorative plastic surgeon. The authors describe the core competencies that characterize this new identity, and discuss the implications of the advent of this new professional paradigm.