Failure of abdominal wall closure after intestinal transplantation: Identifying high‐risk recipients

Multilevel Analysis of the Neovascularization and Integration Process of a Nonvascularized Rectus Fascia Transplantation

Background

Failure to close the abdominal wall after intestinal transplantation (ITx) or multivisceral Tx remains a surgical challenge. An attractive method is the use of nonvascularized rectus fascia (NVRF) in which both layers of the donor abdominal rectus fascia are used as an inlay patch without vascular anastomosis. How this graft integrates over time remains unknown. The study aims to provide a multilevel analysis of the neovascularization and integration process of the NVRF.

Methods

Three NVRF-Tx were performed after ITx. Clinical, radiological, histological, and immunological data were analyzed to get insights into the neovascularization and integration process of the NVRF. Moreover, cryogenic contrast-enhanced microfocus computed tomography (microCT) analysis was used for detailed reconstruction of the vasculature in and around the NVRF (3-dimensional histology).

Results

Two men (31- and 51-y-old) and 1 woman (49-y-old) underwent 2 multivisceral Tx and 1 combined liver-ITx, respectively. A CT scan showed contrast enhancement around the fascia graft at 5 days post-Tx. At 6 weeks, newly formed blood vessels were visualized around the graft with Doppler ultrasound. Biopsies at 2 weeks post-Tx revealed inflammation around the NVRF and early fibrosis. At 6 months, classical 2-dimensional histological analysis of a biopsy confirmed integration of the fascia graft with strong fibrotic reaction without signs of rejection. A cryogenic contrast-enhanced microCT scan of the same biopsy revealed the presence of microvasculature, enveloping and penetrating the donor fascia.

Conclusions

We showed clinical, histological, and microCT evidence of the neovascularization and integration process of the NVRF after Tx.

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.

Allotransplantation of donor rectus fascia for abdominal wall closure in transplant patients: A systematic review

BACKGROUND

Abdominal wall closure after intestinal, multivisceral or liver transplantation can be a major challenge. Different surgical techniques have been described to close complex abdominal wall defects, but results remain variable. Two promising transplant techniques have been developed using either non-vascularized or vascularized donor rectus fascia. This systematic review aimed to evaluate the feasibility, safety, and effectiveness of the two techniques.

METHODS

A systematic review was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Human studies published between January 2000 and April 2020 were included. Methodological quality appraisal was done using an adapted 10-item standardized checklist.

RESULTS

The search resulted in 9 articles including 74 patients. Both techniques proved to be feasible and had similar results. After non-vascularized rectus fascia allotransplantation, there was a slightly higher rate of surgical site infections in the earlier reports. Overall, there were few complications, no fascial graft related rejections or deaths. The included articles scored low on quality appraisal, mostly due to the small number of cases and scarcely reported outcome parameters.

CONCLUSIONS

This systematic literature review reports two emerging new techniques for complex abdominal wall closure in transplant patients, with promising results. Standardized data collection in a prospective manner could give us more detailed information about short- and long-term outcomes. Preclinical animal studies are necessary for a thorough investigation of the mechanisms of graft integration, the risk of hernia development and the alloimmune response against the graft.