Hand allotransplantation

Research status of facial nerve repair

The facial nerve, also known as the seventh cranial nerve, is critical in controlling the movement of the facial muscles. It is responsible for all facial expressions, such as smiling, frowning, and moving the eyebrows. However, damage to this nerve can occur for a variety of reasons, including maxillofacial surgery, trauma, tumors, and infections. Facial nerve injuries can cause severe functional impairment and can lead to different degrees of facial paralysis, significantly affecting the quality of life of patients. Over the past ten years, significant progress has been made in the field of facial nerve repair. Different approaches, including direct suture, autologous nerve grafts, and tissue engineering, have been utilized for the repair of facial nerve injury. This article mainly summarizes the clinical methods and basic research progress of facial nerve repair in the past ten years.

Peripheral nerve repair is associated with augmented cross-tissue inflammation following vascularized composite allotransplantation

Introduction

Vascularized composite allotransplantation (VCA), with nerve repair/coaptation (NR) and tacrolimus (TAC) immunosuppressive therapy, is used to repair devastating traumatic injuries but is often complicated by inflammation spanning multiple tissues. We identified the parallel upregulation of transcriptional pathways involving chemokine signaling, T-cell receptor signaling, Th17, Th1, and Th2 pathways in skin and nerve tissue in complete VCA rejection compared to baseline in 7 human hand transplants and defined increasing complexity of protein-level dynamic networks involving chemokine, Th1, and Th17 pathways as a function of rejection severity in 5 of these patients. We next hypothesized that neural mechanisms may regulate the complex spatiotemporal evolution of rejection-associated inflammation post-VCA.

Methods

For mechanistic and ethical reasons, protein-level inflammatory mediators in tissues from Lewis rats (8 per group) receiving either syngeneic (Lewis) or allogeneic (Brown-Norway) orthotopic hind limb transplants in combination with TAC, with and without sciatic NR, were compared to human hand transplant samples using computational methods.

Results

In cross-correlation analyses of these mediators, VCA tissues from human hand transplants (which included NR) were most similar to those from rats undergoing VCA + NR. Based on dynamic hypergraph analyses, NR following either syngeneic or allogeneic transplantation in rats was associated with greater trans-compartmental localization of early inflammatory mediators vs. no-NR, and impaired downregulation of mediators including IL-17A at later times.

Discussion

Thus, NR, while considered necessary for restoring graft function, may also result in dysregulated and mis-compartmentalized inflammation post-VCA and therefore necessitate mitigation strategies. Our novel computational pipeline may also yield translational, spatiotemporal insights in other contexts.

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.

Building a Hand and Upper Extremity Transplantation Program: Lessons Learned From the First 20 Years of Vascularized Composite Allotransplantation

Background: Upper extremity transplantation is a quality-of-life enhancing treatment for select patients with upper extremity loss. This article reviews the preoperative, intraoperative, and postoperative challenges in the upper extremity transplantation process and the lessons learned from the first 2 decades of hand transplantation. Methods: Key components of the author's hand transplantation protocol including patient selection, donor screening, surgical rehearsal, donor procurement, transplantation, immunosuppression, and patient outcome reporting/follow-up are reported to assist other teams who wish to establish a hand transplantation program. Results: There have been many advancements in the first 20 years of hand transplantation including better patient selection criteria, the recent addition of pediatric patients, improved surgical techniques such as the use of virtual surgical planning, and improved immunosuppression protocols. Improvement has also taken place in the tracking and reporting of hand transplant outcomes, but more work is clearly needed to fully define the benefits of transplantation, especially for pediatric patients. Conclusions: Over the past 20 years, significant progress has been made in upper extremity transplantation although a number of challenges remain including how to best document and share outcome measures, optimize immunosuppression, and diagnose/treat rejection. The authors encourage upper extremity transplant programs to report their experience and protocols to advance hand transplantation as standard of care for properly selected individuals.

First two bilateral hand transplantations in India (Part 4): Immediate post-operative care, immunosuppression protocol and monitoring

Introduction:

Being able to counter immune-mediated rejection has for decades been the single largest obstacle for the progress of vascular composite allotransplantation (VCA). The human immune system performs the key role of differentiating the 'self ' from the 'non-self '. This, although is quintessential to eliminate or resist infections, also resists the acceptance of an allograft which it promptly recognises as 'non-self'.

Materials and Methods:

Pre-operative evaluation of the recipient evaluation included immunological assessment in the form of panel reactive antibodies (PRA), human leucocyte antigen (HLA) typing, donor-specific antibody detection assays (DSA) and complement-dependent cytotoxicity assays (CDC). Induction immunosuppression was by thymoglobulin and the maintenance by the standard triple-drug therapy.

Results:

Both the recipients were managed by the standard triple drug therapy and have had only minor episodes of rejections thus far which have been managed appropriately.

Discussion:

Induction immunosuppression was by thymoglobulin and the maintenance by the standard triple-drug therapy. Various groups have tried various other formulations and regimes as well.

Conclusion:

A comprehensive plan has to be drawn up for immunological screening, selection and the post-operative immunosuppressant usage. The ultimate goal of these immunosuppression modalities is to achieve a state of donor-specific tolerance.

Enhanced Drug Delivery to the Skin Using Liposomes

Background:

Enhancing drug delivery to the skin has importance in many therapeutic strategies. In particular, the outcome in vascularized composite allotransplantation mainly depends on systemic immunosuppression to prevent and treat episodes of transplant rejection. However, the side effects of systemic immunosuppression may introduce substantial risk to the patient and are weighed against the expected benefits. Successful enhancement of delivery of immunosuppressive agents to the most immunogenic tissues would allow for a reduction in systemic doses, thereby minimizing side effects. Nanoparticle-assisted transport by low temperature–sensitive liposomes (LTSLs) has shown some benefit in anticancer therapy. Our goal was to test whether delivery of a marker agent to the skin could be selectively enhanced.

Methods:

In an in vivo model, LTSLs containing doxorubicin (dox) as a marker were administered intravenously to rats that were exposed locally to mild hyperthermia. Skin samples of the hyperthermia treated hind limb were compared with skin of the contralateral normothermia hind limb. Tissue content of dox was quantified both via high-performance liquid chromatography and via histology in skin and liver.

Results:

The concentration of dox in hyperthermia-treated skin was significantly elevated over both normothermic skin and liver. (P < 0.02).

Conclusions:

We show here that delivery of therapeutics to the skin can be targeted and enhanced using LTSLs. Targeting drug delivery with this method may reduce the systemic toxicity seen in a systemic free-drug administration. Development of more hydrophilic immunosuppressants in the future would increase the applicability of this system in the treatment of rejection reactions in vascularized composite allotransplantation. The treatment of other skin condition might be another potential application.

The effect of full dose composite tissue allotransplantation immunosuppression on allograft motor nerve regeneration in a rat sciatic nerve model

BACKGROUND

The purpose of this study was to identify which triple immunosuppressive protocols, currently used for vascularized composite allotransplantation in the clinic, will have the best effect on motor function recovery following nerve allograft reconstruction.

METHODS

Eighty-eight Lewis rats underwent a 1-cm sciatic nerve allograft transplantation and skin graft from 44 Brown-Norway rats. Group I received 0.9% isotonic saline (control); Group II, 2 mg/kg FK506; Group III, 1 mg/kg FK506 with 15 mg/kg mycophenolate mofetil (MMF); and Group IV, 2 mg/kg FK506 with 30 mg/kg MMF and prednisone. Each group consisted of 11 rats. After 12 weeks, motor function recovery was evaluated with isometric tetanic force, muscle mass, ankle contracture angle, electrophysiology, and nerve histomorphometry. Adequacy of immunosuppression was monitored with the transplanted skin graft. All data are expressed as a percentage of the contralateral side.

RESULTS

Isometric tetanic force showed significantly better functional recovery in all groups treated with immunosuppression compared to control. Within the immunosuppression groups no significant difference was found: 42.1 ± 6.4% (Group I), 56.1 ± 12.4% (Group II), 58.4 ± 10.7% (Group III), and 61.3 ± 11.2% (Group IV). Group IV was superior to all other groups regarding ankle contracture (P < .05) and electrophysiology (P < .001). Skin graft rejection occurred in 41 and 0% (Groups III and IV, respectively).

CONCLUSIONS

FK506 significantly enhanced motor recovery after allograft reconstruction. This effect was comparable between combination treatment (low-dose FK506 and MMF) and triple therapy (high-dose FK506 and MMF plus prednisolone). However, triple therapy was more effective in suppressing skin rejection.

Blood product utilization in human upper-extremity transplantation: challenges, complications, considerations, and transfusion protocol conception

BACKGROUND

Upper-extremity transplantation (UET) is a reality. Immunologic, functional, and graft survival outcomes have been encouraging. However, these complex reconstructions have unique considerations that pose distinct challenges. Transplant programs have reported morbidity and mortality due to significant intraoperative blood losses, but similar data are scant during other phases of recovery. We report experience from two centers on complete blood component demands and utilization with UET.

STUDY DESIGN AND METHODS

Inpatient medical records of UET recipients from intraoperative (time from initiation of transplant surgery to exit from the operative suite) and postoperative (exit from the operative suite to discharge from the hospital) phases were retrospectively reviewed.

RESULTS

Six patients received various UETs and mean (±SD) postoperative hospital stay was 46 (±14.4) days. Mean (±SD) intraoperative blood unit utilization was 14.8 (±10.2) red blood cells (RBCs), 10.5 (±11.8) plasma, 0.8 (±1.2) platelets (PLTs), and 0.3 (±0.8) cryoprecipitate units. Mean postoperative blood unit utilization was 9.3 (±10.4) RBCs, 5.3 (±6.7) plasma, 1.2 (±2.0) PLTs, and 0.7 (±1.6) cryoprecipitate units. Both intraoperative and postoperative blood utilization for unilateral versus bilateral transplant were different, but not significantly so. However, total inpatient blood use in bilateral transplants was significantly greater than in unilateral transplants.

CONCLUSION

Substantial blood loss may occur in UET and require transfusion of many blood components, primarily RBCs and plasma. We propose an UET transfusion protocol and suggest that centers preparing to perform these transplants should actively engage the transfusion medicine service to ensure availability and access to appropriate blood components for the entire hospitalizations of these unique patients.

Emerging Implications for Extracellular Matrix-Based Technologies in Vascularized Composite Allotransplantation

Despite recent progress in vascularized composite allotransplantation (VCA), limitations including complex, high dose immunosuppression regimens, lifelong risk of toxicity from immunosuppressants, acute and most critically chronic graft rejection, and suboptimal nerve regeneration remain particularly challenging obstacles restricting clinical progress. When properly configured, customized, and implemented, biomaterials derived from the extracellular matrix (ECM) retain bioactive molecules and immunomodulatory properties that can promote stem cell migration, proliferation and differentiation, and constructive functional tissue remodeling. The present paper reviews the emerging implications of ECM-based technologies in VCA, including local immunomodulation, tissue repair, nerve regeneration, minimally invasive graft targeted drug delivery, stem cell transplantation, and other donor graft manipulation.

Engineered composite tissue as a bioartificial limb graft

The loss of an extremity is a disastrous injury with tremendous impact on a patient's life. Current mechanical prostheses are technically highly sophisticated, but only partially replace physiologic function and aesthetic appearance. As a biologic alternative, approximately 70 patients have undergone allogeneic hand transplantation to date worldwide. While outcomes are favorable, risks and side effects of transplantation and long-term immunosuppression pose a significant ethical dilemma. An autologous, bio-artificial graft based on native extracellular matrix and patient derived cells could be produced on demand and would not require immunosuppression after transplantation. To create such a graft, we decellularized rat and primate forearms by detergent perfusion and yielded acellular scaffolds with preserved composite architecture. We then repopulated muscle and vasculature with cells of appropriate phenotypes, and matured the composite tissue in a perfusion bioreactor under electrical stimulation in vitro. After confirmation of composite tissue formation, we transplanted the resulting bio-composite grafts to confirm perfusion in vivo.

Changing attitudes toward hand allotransplantation among North American hand surgeons

OBJECTIVES

Although more than 70 hand transplants have been performed worldwide, the appropriate clinical indications for this operation are still being determined. Cost and patient exposure to the challenges of lifelong immunosuppression for what is a quality of life-improving (but not life-saving) operation are the focus of the ongoing discussion. A study performed in 2007 showed that surgeons' opinions on the issue varied widely. Recently, more information has been made available regarding long-term patient outcomes, and significant improvements in immunotherapy protocols have been reported. In light of this, we sought to examine changing attitudes regarding hand allotransplantation and its indications by surveying hand surgeons.

METHODS

An email-based survey was sent to members of the American Society for Surgery of the Hand. Demographic information and practice profiles were identified, followed by their risk assessment of hand allotransplants and endorsement of performing the operation in different clinical scenarios. Additional questions focused on the appropriate indications for hand allotransplantation, as well as the procedure's associated ethical and financial implications.

RESULTS

A total of 385 surgeons responded to the survey (14% response rate). The majority (82%) considered hand transplantation to be a high-risk operation (as opposed to 27% in hand replantation), with 78% citing lifelong immunosuppression as the primary factor impacting their overall risk assessment. The most commonly accepted indication for hand vascularized composite allotransplantation was loss of bilateral hands (80% in favor). Dominant hand loss (with an intact contralateral hand) was a far less frequently accepted indication (36% in favor). Patient adherence to immunosuppressive regimens (51%) and expectations of functional/aesthetic outcome (38%) were the most frequently chosen top psychosocial issues that must be addressed by the surgical/medical teams involved in the operation.

CONCLUSIONS

Our study's results demonstrate increasing overall support for hand allotransplantation and increasing acceptance of today's immunosuppressive regimens compared to prior literature. Bilateral hand loss remains the primary agreed-upon indication for transplantation. Despite increasing acceptance in the surgical community, the dangers of chronic immunosuppression, cost and patient adherence continue to be the primary concerns hindering its broader acceptance.

Upper extremity transplantation: current concepts and challenges in an emerging field

Loss of an isolated upper limb is an emotionally and physically devastating event that results in significant impairment. Patients who lose both upper extremities experience profound disability that affects nearly every aspect of their lives. While prosthetics and surgery can eventually provide the single limb amputee with a suitable assisting hand, limited utility, minimal haptic feedback, weight, and discomfort are persistent problems with these techniques that contribute to high rates of prosthetic rejection. Moreover, despite ongoing advances in prosthetic technology, bilateral amputees continue to experience high levels of dependency, disability, and distress. Hand and upper extremity transplantation holds several advantages over prosthetic rehabilitation. The missing limb is replaced with one of similar skin color and size. Sensibility, voluntary motor control, and proprioception are restored to a greater degree, and afford better dexterity and function than prosthetics. The main shortcomings of transplantation include the hazards of immunosuppression, the complications of rejection and its treatment, and high cost. Hand and upper limb transplantation represents the most commonly performed surgery in the growing field of Vascularized Composite Allotransplantation (VCA). As upper limb transplantation and VCA have become more widespread, several important challenges and controversies have emerged. These include: refining indications for transplantation, optimizing immunosuppression, establishing reliable criteria for monitoring, diagnosing, and treating rejection, and standardizing outcome measures. This article will summarize the historical background of hand transplantation and review the current literature and concepts surrounding it.

Composite tissue transplantation

Composite tissue transplantation is an emerging new era in transplant medicine and has become a viable reconstructive option for patients with large and devastating tissue defects. Advances in microsurgical techniques, transplant immunology and the development of potent immunosuppressive agents have enabled the realization of such types of transplants. Over the past decade, a rapidly growing number of face and upper extremity transplantations have been performed worldwide with highly encouraging outcomes. However, despite the fact that surgical, immunological and functional results are highly encouraging, the need for long-term and high-dose immunosuppression to enable graft survival and to treat/reverse acute skin rejection episodes remains a pace-limiting obstacle towards wide spread application. In this chapter we review the history and development of this novel field, the functional and immunological outcomes based on the world experience, unique biological features of such transplants, mechanisms and treatment protocols for acute skin rejection, as well as novel concepts for immune modulation and tolerance induction.

Face allotransplantation and burns: a review

Burns may represent one of the main indications for face allotransplantation. Severely disfigured faces featuring a devastating appearance and great functional impairments are not only seen as burn sequelae but also occur as a result of other traumatic injuries, oncological surgical resections, benign tumors (eg, neurofibromatosis), and major congenital malformations. To date, 20 human face composite tissue allotransplants have been performed with success. Despite the initial scepticism about its applicability, due mainly to ethical and technical reasons, the previous worldwide cases and their associated positive outcomes, including acceptable immunosuppressive regimens, excellent aesthetic and functional results, and good psychological acceptance by the recipient, enable the conclusion that face composite tissue allotransplantation has become another therapeutic strategy in the reconstructive surgical armamentarium, which bears special consideration when dealing with severely disfigured burned patients. The aim of this review is to describe the basics of face composite tissue allotransplantation and give an overview of some of the cases performed until now, with special attention paid to debating the pros and cons of its applicability in burn patients.

Anesthetic management in upper extremity transplantation: the Pittsburgh experience

BACKGROUND

Hand/forearm/arm transplants are vascularized composite allografts, which, unlike solid organs, are composed of multiple tissues including skin, muscle, tendons, vessels, nerves, lymph nodes, bone, and bone marrow. Over the past decade, 26 upper extremity transplantations were performed in the United States. The University of Pittsburgh Medical Center has the largest single center experience with 8 hand/forearm transplantations performed in 5 recipients between January 2008 and September 2010. Anesthetic management in the emerging field of upper extremity transplants must address protocol and procedure-specific considerations related to the role of regional blocks, effects of immunosuppressive drugs during transplant surgery, fluid and hemodynamic management in the microsurgical setting, and rigorous intraoperative monitoring during these often protracted procedures.

METHODS

For the first time, we outline salient aspects of upper extremity transplant anesthesia based on our experience with 5 patients. We highlight the importance of minimizing intraoperative vasopressors and improving fluid management and blood product use.

RESULTS

Our approach reduced the incidence of perioperative bleeding requiring re-exploration or hemostasis and shortened in-hospital and intensive care unit stay. Functional, immunologic and graft survival outcomes have been highly encouraging in all patients.

CONCLUSIONS

Further experience is required for validation or standardization of specific anesthetic protocols. Meanwhile, our recommendations are intended as pertinent guidelines for centers performing these novel procedures.

Functional outcome after hand and forearm transplantation: what can be achieved?

The first successful hand transplant in the modern era of reconstructive transplantation was performed in 1998. Since then, more than 65 hand and upper limb transplantations have been performed around the globe, with encouraging results. The main goal of all upper limb transplantations is to enhance the patient's quality of life. The transplant must be successfully integrated into the patient's body and self-image and the recipient should be satisfied with the recovery of sensitivity and muscle function of the new limb. To achieve these goals, a proper and thorough design of the rehabilitation regimen is of critical importance.

The history and evolution of hand transplantation

Hand transplantation has proven itself to be a viable treatment option for upper extremity reconstruction. It has grown through advancements in several critical areas: microsurgery, transplant immunology, and hand surgery. The field has also benefited from a global effort with active transplant centers in 3 different continents. The early struggles and breakthroughs of hand transplantation's past have shaped and formed its current state. This article traces the events of the modern era of hand transplantation.

Acute and chronic rejection in upper extremity transplantation: what have we learned?

To date, 78 upper extremity transplants have been performed in 55 recipients around the world. The purpose of this article is to provide an overview of acute and chronic rejection (CR) and to summarize collective insights in upper extremity transplantation. To date, almost all patients experienced AR that is pathophysiologically similar to that in solid organs. The spectre of chronic rejection is just emerging. Upper extremity transplantation has significant potential as a reconstructive option only if efforts are invested in strategies to reduce risks of prolonged immunosuppression and in approaches to better diagnose, monitor and treat AR and CR.