Use of Abdominal Wall Allotransplantation as an Alternative for the Management of End Stage Abdominal Wall Failure in a Porcine Model

Heterotopic intestine and abdominal wall transplantation in a miniature swine: A model for graft immunology

In order to accurately monitor graft immunology, we have developed a method for performing intestine and abdominal wall transplantation heterotopically in miniature swine. The procedure consisted of simultaneous segmental terminal ileum and full-thickness abdominal wall transplantation in Lanyu miniature swine, with the intestinal and the abdominal wall grafts being placed on the recipient's bilateral rear flank. Five transplantations were technically successful. One animal died on the first post-transplant day due to anesthesia-related issues, three abdominal wall and four intestinal grafts survived, while one abdominal wall graft failed due to vascular thrombosis. Acute cellular rejection (ACR) of the intestinal graft could occur preceding, simultaneously with or following ACR of the abdominal wall graft. Our experimental model demonstrates the technical feasibility of heterotopic intestine and abdominal wall transplantation in miniature swine without grafting in gastrointestinal continuity. This model could be suitable for further studies of graft immunology.

Abdominal Wall Vascularized Composite Allotransplantation: A Scoping Review

BACKGROUND

 Abdominal wall vascularized composite allotransplantation (AW-VCA) is a novel reconstructive technique used for large abdominal wall defects in combination with intestinal transplantation (ITx) or multivisceral abdominal transplantation (MVTx). Since the introduction of this procedure, several studies have been published reporting their experience. This study aims to present a scoping review looking at all available evidence-based medicine information to understand the most current surgical techniques and clinical outcomes.

METHODS

 This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) extension for scoping reviews checklist. A comprehensive research strategy of several databases was conducted.

RESULTS

 A total of 31 studies were included in this review, which comprised animal, cadaveric, and human studies. In human studies, four surgical techniques with high flap survival rates and low complication rates were found. In cadaveric studies, it was shown that the use of iliofemoral cuff-based flaps provided adequate tissue perfusion to the abdominal wall graft. Also, the use of thoracolumbar nerves have been described to provide functionality to the AW-VCA and prevent long-term muscle atrophy.

CONCLUSION

 AW-VCA is a safe and efficient alternative for patients with large and complex abdominal wall defects. The future holds a promising evolution of a functional AW-VCA, though surgeons must face and overcome the challenge of distorted anatomy frequently present in this population. Forthcoming studies with a better level of evidence are required to evaluate functionality and differences between surgical techniques.

Abdominal wall allotransplantation

Allotransplantation of vascularized composite tissue is a new field of transplantation surgery. One application of this technique is abdominal wall transplantation used as a supplementary procedure to the transplantation of visceral organs in patients with abdominal compartment deficits. As abdominal wall closure problems are experienced in around 30-40% of such patients, peer reviewed conclusions on the viability of various options, are important for an informed choice of possible procedures. This review focuses on the abdominal wall allotransplantion procedure. Our search provided 35 appropriate references which we used to support our findings as follows: abdominal wall transplantation was performed in 33 patients at seven centres. Of these, 30 had a full thickness abdominal wall transplanted from the same donor, 3 from a second donor. Three had visceral organ transplants and in addition, the posterior sheet of the rectus muscle fascia. In summary, our findings were that abdominal wall allotransplantation does not jeopardize the outcome of visceral organs transplantation. There is no higher risk of complications or rejection of the visceral organs. There have been no fatalities as a direct result of complications due to abdominal wall transplantation. Finally, the transplanted abdominal wall may provide an early warning of rejection before diagnostic tests on the bowel are symptomatic.

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.

Current concepts and systematic review of vascularized composite allotransplantation of the abdominal wall

INTRODUCTION

Abdominal wall vascularized composite allotransplantation (AW-VCA) is a rarely utilized technique for large composite abdominal wall defects. The goal of this article is to systematically review the literature and current concepts of AW-VCA, outline the challenges ahead, and provide an outlook for the future.

METHODS

Systematic review of the literature was performed using MEDLINE, EMBASE, and PubMed to identify relevant articles discussing results of AW-VCA. Cadaver and animal studies were excluded from the systematic review, but selectively included in the discussion.

RESULTS

The resultant five papers report their results on AW-VCA(Transplantation, 85, 2008, 1607; Am J Transplant, 7, 2007, 1304; Transplant Proc, 41, 2009, 521; Transplant Proc, 36, 2004, 1561; Lancet, 361, 2003, 2173). These papers represent the result of two study groups in which a total of 18 AW-VCA were performed in 17 patients. Two different operative approaches were used. Overall flap/graft survival was 88%. No mortality related to the transplant was reported. One cadaver study and two animal models were identified and separately presented (Transplant Proc, 43, 2011, 1701; Transplantation, 90, 2010, 1590; Journal of Surgical Research, 162, 2010, 314).

CONCLUSION

Literature review reports AW-VCA is technically feasible with low morbidity and mortality. Functional outcomes are not reported and minimally considered. With advancements in vascularized composite allotransplantation research and decreasing toxicity of immunosuppression therapies and immunomodulatory regimens, AW-VCA can be applied in circumstances beyond conjunction with visceral transplantation.