Institutional review board-based recommendations for medical institutions pursuing protocol approval for facial transplantation. Plast Reconstr Surg. 2010;126:1232-1239. [PMID: 20885245 DOI: 10.1097/PRS.0b013e3181ee482d]

Psychosocial predictors in upper-extremity vascularized composite allotransplantation: A qualitative study of multidimensional experiences including patients, healthcare professionals, and close relatives

Background

The impact of patient-specific psychosocial factors on functional outcomes after upper-extremity (UE) vascularized composite allotransplantation (VCA) is poorly understood. The objective of this study was to identify relevant psychosocial predictors for success or failure of UE VCA in an Austrian cohort.

Methods

A qualitative study was undertaken consisting of semi-structured interviews with UE VCA staff, transplanted patients, and close relatives. Participants were asked about their perceptions of factors that either favored or hindered a successful transplant outcome, including functional status before surgery, preparation for transplant, decision-making, rehabilitation and functional outcome after surgery, and family and social support. Interviews were conducted online and recorded with the consent of interviewees.

Results

Four bilateral UE VCA patients, 7 healthcare professionals, and a sister of a patient participated in the study. Thematic analysis revealed the importance of an expert interdisciplinary team with adequate resources for patient selection. Psychosocial aspects of prospective candidates are crucial to evaluate as they contribute to success. Both patients and providers may be impacted by public perceptions of UE VCA. Functional outcomes are optimized with a life-long commitment to rehabilitation as well as close, ongoing provider involvement.

Conclusion

Psychosocial factors are important elements in the assessment and follow-up care for UE VCA. To best capture psychosocial elements of care, protocols must be individualized, patient-centered, and interdisciplinary. Investigating psychosocial predictors and collecting outcomes is, thus, critical to justifying UE VCA as a medical intervention and to providing accurate and salient information to prospective candidates.

Strategic Planning and Essential Steps for Establishing a Uterine Transplant and Rehabilitation Program: From Idea to Reality

UTx is performed to address absolute uterine infertility in the presence of uterine agenesis, a nonfunctional uterus, or after a prior hysterectomy. After the initial success of UTx resulting in a livebirth (2014) in Sweden, there are over 70 reported UTx surgeries resulting in more than 40 livebirths worldwide. Currently, UTx has been performed in over 10 countries. As UTx is transitioning from an "experimental procedure" to a clinical option, an increasing number of centers may contemplate a UTx program. This article discusses essential steps for establishment of a successful UTx program. These principles may be implemented in cis- and transgender UTx candidates.

Recipient Selection Criteria for Facial Transplantation: A Systematic Review

BACKGROUND

Recipient selection is an important determinant of surgical outcomes in facial transplantation (FT). Appropriately, each FT program develops their own guidelines for recipient selection criteria. Currently, there is no resource to simultaneously assess and identify similarities and differences between these guidelines. Such information could be useful in distinguishing areas of FT that are well understood from those that could benefit from further exploration.

METHODS

We performed a systematic review of the scientific literature from inception to June 18, 2021, using Pubmed, Embase, Cochrane Library, and Scopus to identify articles pertaining to recipient selection criteria. Clinical trials were identified through the Clinicaltrials.gov registry. United States and international program websites were reviewed for patient-facing information.

RESULTS

Our systematic review yielded 90 suitable articles, 8 clinical trials, and 7 program websites containing the recipient selection criteria of 24 different FT programs. The most reported on recipient criteria were age, positive human immunodeficiency viral status (HIV+), positive hepatitis C viral status, psychosocial stability, and medical compliance. Other criteria were rarely addressed, such as blindness and recipient immune status.

CONCLUSIONS

Guidelines among different face transplant programs are changing over time. We found consensus on certain recipient selection criteria, but the majority remain program or surgeon dependent, emphasizing that FT is still an evolving procedure. Although most programs reported on their recipient selection criteria, the rationale was often missing. Further discussion about recipient selection criteria and the reasoning behind employing or changing them will help advance the field.

Cytomegalovirus-related Complications and Management in Facial Vascularized Composite Allotransplantation: An International Multicenter Retrospective Cohort Study

BACKGROUND

There is a paucity of data on the impact of cytomegalovirus (CMV) serostatus and CMV infection on outcomes in facial vascularized composite allotransplantation.

METHODS

This international, multicenter, retrospective cohort study presents data on CMV and basic transplant-related demographics, including pretransplant viral D/R serostatus, and duration of antiviral prophylaxis. CMV-related complications (viremia, disease), allograft-related complications (rejection episodes, loss), and mortality were analyzed.

RESULTS

We included 19 patients, 4 of whom received CMV high-risk transplants (D+/R-). CMV viremia was noted in 6 patients (all 4 D+/R- patients and 2 D-/R+), mostly within the first-year posttransplant, shortly after discontinuation of antiviral prophylaxis (median 2 mo). CMV disease occurred in 2 D+/R- patients. The high-risk group experienced relatively more rejection episodes per month follow-up. None of D+/R- patients suffered allograft loss due to rejection (longest follow-up: 121 mo).

CONCLUSIONS

D+/R- patients were at increased risk of CMV-related complications. Although a higher number of rejections was noted in this group, none of the D+/R- patients lost their allograft or died because of CMV or rejection. Thus, CMV D+/R- face transplantation can likely be safely performed with prophylaxis, active surveillance, and prompt treatment.

Donor and Recipient Matching in Facial Vascularized Composite Allotransplantation: A Closer Look at the Donor Pool

BACKGROUND

Identifying a donor for facial vascularized composite allotransplant recipients can be a lengthy, emotionally challenging process. Little is known about the relative distribution of key donor characteristics among potential donors. Data on actual wait times of patients are limited, making it difficult to estimate wait times for future recipients.

METHODS

The authors retrospectively reviewed charts of nine facial vascularized composite allotransplant patients and provide data on transplant wait times and patient characteristics. In addition, they analyzed the United Network for Organ Sharing database of dead organ donors. After excluding donors with high-risk characteristics (e.g., active cancer or risk factors for blood-borne disease transmission), the authors calculated the distribution of relevant donor-recipient matching criteria (i.e., ethnicity, body mass index, age, ABO blood group, cytomegalovirus, Epstein-Barr virus, hepatitis C virus) among 65,201 potential donors.

RESULTS

The median wait time for a transplant was 4 months (range, 1 day to 17 months). The large majority of United Network for Organ Sharing-recorded deaths from disease were white (63 percent) and male (58 percent). Female donors of black, Hispanic, or Asian descent are underrepresented, with 7, 5, and 1 percent of all recorded deaths from disease, respectively. Potential donors show cytomegalovirus and Epstein-Barr virus seropositivity of 65 and 95 percent, respectively. The number of annual hepatitis C-positive donors increased over time.

CONCLUSIONS

Actual facial vascularized composite allotransplant wait times vary considerably. Although most patients experience acceptable wait times, some with underrepresented characteristics exceed acceptable levels. Cytomegalovirus-seropositive donors present a large portion of the donor pool, and exclusion for seronegative patients may increase wait time. Hepatitis C-seropositive donors may constitute a donor pool for underrepresented patient groups in the future.

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.

Ocular Considerations in Face Transplantation: Report of 2 Cases and Review of the Literature

PURPOSE

Periorbital injuries are common in face transplantation (FT) candidates. It is therefore essential that the ophthalmologist play a central role in the multidisciplinary treatment of these patients. In this study, the authors perform a comprehensive review of all procedures involving periorbital components, provide an update for the ophthalmology community regarding the current state of the field, and present 2 cases.

METHODS

A comprehensive review of the literature for all FT procedures including periorbital components was performed. The authors also present 2 patients who received FT including periorbital components for extensive facial disfigurement. One patient sustained high-energy avulsive ballistic injury and underwent a total face, double jaw, and tongue transplant in 2012. The second patient received a total face, eyelids, ears, and skeletal subunits transplant for extensive facial burns in 2015.

RESULTS

Literature review demonstrated that 22 (54%) of the 41 patients undergoing FT received allografts containing periorbital components. Only 14 cases (64%) reported on the presence of ocular and periocular complications. The most common complications consisted of lower eyelid ectropion and lagophthalmos, and nearly all required revisional procedures. Both patients presented with significant periorbital scarring and demonstrated good visual acuity and aesthetic outcomes at postoperative follow up between 6 and 28 months.

CONCLUSIONS

Face transplantation can address extensive facial and periorbital disfigurement with satisfactory functional and aesthetic outcomes. The majority of FT performed to date have included periorbital components, and postoperative ocular and periocular complications are common. It is critical for ophthalmologists to play a central role in the care of these patients.

A European perspective of the cost effectiveness of facial composite tissue allotransplantation

Background

Facial composite tissue allotransplantation (CTA) may be considered in cases of severe facial injury. To date, no reports have analysed the cost of potential facial CTA in the UK. The aims of this study were to establish (1) the cost implications without facial CTA, necessitating multiple reconstructive procedures in cases with severe facial deformities, and (2) if facial CTA would be cost-effective in the UK given recent European and North American published cost analyses.

Methods

Hospital episodes’ data from two potential candidates for facial CTA were used to calculate cost of treatment. In these cases, severe facial trauma was managed by multiple disciplinary teams performing numerous conventional reconstructive procedures. One case served as an indicator of the cost of primary reconstruction during the immediate post-traumatic episode, from admission until first discharge. The other served as an indicator of the accumulative cost of care following primary reconstruction from first discharge to six years later. Costs incurred served as a guide for the cost of standard reconstruction in the UK. These were compared with the costs of similar reconstructive procedures performed in the USA. This was used with data reporting the cost of facial CTA in the USA and France to predict the cost of facial CTA in the UK.

Results

Analysis revealed a cost benefit for facial CTA in a UK context that would become apparent from the third year post-transplant onwards.

Conclusion

Facial CTA may therefore be a more cost-effective long-term reconstructive option for patients with severe facial defects.

Level of evidence: Level V, risk/prognostic study.

Self-Inflicted Gunshot Wound as a Consideration in the Patient Selection Process for Facial Transplantation

Facial transplantation is emerging as a therapeutic option for self-inflicted gunshot wounds. The self-inflicted nature of this injury raises questions about the appropriate role of self-harm in determining patient eligibility. Potential candidates for facial transplantation undergo extensive psychosocial screening. The presence of a self-inflicted gunshot wound warrants special attention to ensure that a patient is prepared to undergo a demanding procedure that poses significant risk, as well as stringent lifelong management. Herein, we explore the ethics of considering mechanism of injury in the patient selection process, referring to the precedent set forth in solid organ transplantation. We also consider the available evidence regarding outcomes of individuals transplanted for self-inflicted mechanisms of injury in both solid organ and facial transplantation. We conclude that while the presence of a self-inflicted gunshot wound is significant in the overall evaluation of the candidate, it does not on its own warrant exclusion from consideration for a facial transplantation.

The Helsinki approach to face transplantation

AIM

We herein describe the establishment of the Helsinki Vascularized Composite Allotransplantation (VCA) program and its execution in the first two face transplant cases.

METHODS & PATIENTS

The Helsinki VCA program initially required the fulfillment of legal, hospital, financial, and ethical requirements. Thereafter, the assembling of a multidisciplinary team commenced. A team of Plastic, maxillofacial and ENT surgeons comprise the facial VCA team. The protocol involves collaboration with the Solid Organ Transplant (SOT) team, transplant immunology, immunosuppression, microbiology, psychiatric evaluation, well-defined VCA indications and informed consent. Between 2011 and 2017 two patients were selected for transplantation. Both patients had a severe composite facial deformity involving the maxilla and mandible following earlier ballistic injury.

RESULTS

Patient 1 was a 35 year-old male who underwent successful near total face transplantation in February 2016 and at 30 months he has a good aesthetic outcome with symmetrical restoration of the central face and good sensory and symmetrical motor functional outcomes. Patient 2 was a 58 year-old male who underwent full face transplantation in March 2018 and at 5 months he has recovered without major problems.

CONCLUSION

A successful facial VCA program requires a well-prepared research protocol, experts from multiple specialties and careful patient selection. The establishment of the Helsinki VCA program required long and thorough planning and resulted in the first two Nordic face transplantation cases. This protocol now forms the platform (as a proof of concept) for other types of vascularized composite allotransplantations.

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.

Effect of Cold Preservation on Chronic Rejection in a Rat Hindlimb Transplantation Model

BACKGROUND

Previous studies on solid organ transplantation have shown that cold ischemia contributes to the development of chronic allograft vasculopathy. The authors evaluated the effect of cold ischemia on the development of chronic rejection in vascularized composite allotransplantation.

METHODS

Thirty rat hindlimbs were transplanted and divided into two experimental groups: immediate transplantation and transplantation after 7 hours of cold ischemia. The animals received daily low-dose immunosuppression with cyclosporine A for 2 months. Intimal proliferation, arterial permeability rate, leukocyte infiltration, and tissue fibrosis were assessed. The CD3, CD4, CD8, CD20, and CD68 cells per microscopic field (200×) were counted, and C4d deposition was investigated. Cytokine RNA analysis was performed to measure tumor necrosis factor-α, interleukin-6, and interleukin-10 levels.

RESULTS

Significant differences were found in the intimal proliferation and arterial permeability rate between the two groups (p = 0.004). The arterial permeability rate worsened in the most distal and small vessels (p = 0.047). The numbers of CD3, CD8, CD20, and CD68 were also statistically higher in the cold ischemia group (p < 0.05, all levels). A trend toward significance was observed with C4d deposition (p = 0.059). No differences were found in the RNA of cytokines.

CONCLUSIONS

An association between cold ischemia and chronic rejection was observed in experimental vascularized composite allotransplantation. Chronic rejection intensity and distal progression were significantly related with cold ischemia. The leukocyte infiltrates in vascularized composite allotransplantation components were a rejection marker; however, their exact implication in monitoring and their relation with cold ischemia are yet to be clarified.

The decade of face transplant outcomes

At the 10th year anniversary of the first face transplantation, 37 patients worldwide, were the recipients of faces coming from human donors. Five patients died due to complications, noncompliance with immunosuppressive medications and development of cancer. Despite the initial debates and ethical concerns, face transplantation became a clinical reality with satisfactory functional outcomes. The areas of controversy still include the impact of life-long immunosuppression on otherwise healthy patients as well as the selection process of face transplant candidates. Other concerns include financial support for this new generation of transplants as well as social re-integration and patients return to work after face transplantation. Based on over 20 years of research experience in the field of vascularized composite allotransplantation (VCA), and clinical experience as a leading surgeon of the US first face transplantation, this review will summarize the well-known facts as well as unexpected outcomes and challenges of face transplantation.

The miracle of face transplantation after 10 years

INTRODUCTION

At the 10th year anniversary of the first face transplantation, there are currently 36 patients worldwide, who are the recipients of faces coming from human donors.

AREAS OF AGREEMENT

Despite the initial debates and ethical concerns, face transplantation became a clinical reality with satisfactory functional outcomes.

AREAS OF CONTROVERSY

The areas of controversy still include the impact of lifelong immunosuppression on otherwise healthy patients as well as the selection process of face transplant candidates.

GROWING POINTS

Other concerns include financial support for this new generation of transplants as well as social reintegration and patients return to work after face transplantation.

AREAS TIMELY FOR DEVELOPING RESEARCH

Based on over 20 years of research experience in the field of vascularized composite allotransplantation, and clinical experience as a leading surgeon of the US first face transplantation, this review will summarize the well-known facts as well as unexpected outcomes and challenges of face transplantation.

Key psychosocial challenges in vascularized composite allotransplantation

Psychosocial factors are important elements in the assessment and follow-up care for vascularized composite allotransplantation (VCA) and require multidisciplinary evaluation protocols. This review will highlight differences between VCA with solid organ transplantation (SOT), provide information on the psychosocial selection of VCA candidates, ethical issues, psychological outcomes, and on the need for multicenter research. VCA is primarily a life-enhancing procedure to improve recipients' quality of life and psychological well-being and it represents a potential option to provide reproduction in case of penile or uterine transplantation. The risk benefit ratio is distinctly different than SOT with candidates desiring life enhancing outcomes including improved body image, return to occupations, restored touch, and for uterine transplant, pregnancy. The Chauvet Workgroup has been convened with membership from a number of transplant centers to address these issues and to call for multicenter research. A multicenter research network would share similar evaluation approaches so that meaningful research on psychosocial variables could inform the transplant community and patients about factors that increase risk of non-adherence and other adverse psychosocial and medical outcomes.

Facial transplantation: the first 9 years

Since the first facial transplantation in 2005, 28 have been done worldwide with encouraging immunological, functional, psychological, and aesthetic outcomes. Unlike solid organ transplantation, which is potentially life-saving, facial transplantation is life-changing. This difference has generated ethical concerns about the exposure of otherwise young and healthy individuals to the sequelae of lifelong, high-dose, multidrug immunosuppression. Nevertheless, advances in immunomodulatory and immunosuppressive protocols, microsurgical techniques, and computer-aided surgical planning have enabled broader clinical application of this procedure to patients. Although episodes of acute skin rejection continue to pose a serious threat to face transplant recipients, all cases have been controlled with conventional immunosuppressive regimens, and no cases of chronic rejection have been reported.

Vascularized Composite Allografts: Procurement, Allocation, and Implementation

Vascularized composite allotransplantation is a continuously evolving area of modern transplant medicine. Recently, vascularized composite allografts (VCAs) have been formally classified as 'organs'. In this review, key aspects of VCA procurement are discussed, with a special focus on interaction with the procurement of classical solid organs. In addition, options for a matching and allocation system that ensures VCA donor organs are allocated to the best-suited recipients are looked at. Finally, the different steps needed to promote VCA transplantation in society in general and in the medical community in particular are highlighted.

Facial transplantation in a blind patient: psychologic, marital, and family outcomes at 15 months follow-up

BACKGROUND

Quality of life has frequently been reported to improve after vascularized composite allotransplantation of the face. However, psychosocial functioning of the partner or of particular patient groups such as blind patients are until now less well investigated.

OBJECTIVE

The aim of this study is to investigate psychologic, marital, and family functioning of a blind 54-year-old patient, Mr. A, and his partner after facial transplantation.

METHODS

Depressive and anxiety symptoms, hopelessness, personality, coping, resilience, illness cognitions, marital support, dyadic adjustment, family functioning, and quality of life of Mr. A and his partner were assessed before and after facial transplantation and at 15 months follow-up. Reliable change index (RCI) was further calculated to evaluate the magnitude of change.

RESULTS

Most psychologic, marital, and family scores of both Mr. A and his partner were within a normative and healthy range before and after transplant and at 15 months follow-up. Resilience (RCI: 3.6), affective responsiveness (RCI: -3.6), and disease benefits (RCI: 2.6) of Mr. A further improved at 15 months follow-up whereas the physical quality of life (RCI: -14.8) strongly decreased. Only marital support (RCI: -2.1) and depth (RCI: -2.0) of the partner decreased at 15 months.

CONCLUSIONS

The results of this study point to positive psychosocial outcomes in a blind patient after facial transplantation. Further, they may underscore the importance of good psychosocial functioning before transplantation of both partners and of their involvement in psychologic and psychiatric treatment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

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.

Evolution and trends in reconstructive facial surgery: an update

Surgical correction of congenital and acquired facial deformities has transcended the primitive era of using non biologic materials to current attempts at own face growing through biotechnology. A summative account of this trend is still lacking in the literature. The objective of this article is to present an update on current knowledge in the strides to achieve functionally and aesthetically perfect facial reconstruction. It highlights the impact of advancements in 3D imaging, stereolithographic biomodelling, microvascular surgical tissue transplantation and tissue biotechnology in the surgical efforts to solve the problems of facial disfigurement whether congenital or acquired.

Craniomaxillofacial reconstruction using allotransplantation and tissue engineering: challenges, opportunities, and potential synergy

The face is composed of an intricate underlying bony/cartilaginous framework that supports muscle, secretory organs, and sophisticated skin/subcutaneous structures. These components are attached through numerous ligaments and interact dynamically with a vast neurovascular network. The most sophisticated autologous reconstructive techniques, utilizing composite free-tissue flaps, are often inadequate to restore extensive maxillofacial defects. Massive craniomaxillofacial (CMF) defects resulting from trauma, oncologic resection, or congenital deformity present a unique challenge to reconstructive surgeons. Therefore, recent advances in craniofacial surgery and immunotherapy spurred the innovation of composite tissue allotransplantation (CTA), which permits reconstruction with tissue composed of all necessary components. However, CMF allotransplantation carries with it side effects of lifelong immunosuppression. Furthermore, the donor skeletal framework may not provide an ideal match, resulting in less than ideal occlusion and soft-tissue anthropometrics. An alternative to transplantation, tissue engineering, has provided hope for regenerating missing tissue and avoiding the need for immunosuppression. Many tissue subtypes, including bone and cartilage, have been successfully created, with sparse reports of clinical application. Tissue-engineered composite tissue required for complete CMF reconstruction continues to elude development, with vascular supply and tissue interactions posing the largest remaining obstacles. We report herein the current status and limitations of CTA and tissue engineering. Furthermore, we describe for the first time our vision of hybridization of CTA and engineering, utilizing the strengths of each strategy.