Closing the abdomen: update on the current surgical toolkit

Intestinal transplantation in Familial Adenomatous Polyposis

In patients with Familial Adenomatous Polyposis (FAP), large desmoid tumors can develop all over the body. However, the most frequent presentation is as large intra-abdominal masses, usually located in the mesentery of the small bowel. From there, they tend to grow and invade both the abdominal wall and/or the retroperitoneal structures. This can cause life-threatening complications such as recurrent abdominal sepsis with fistulation and damage to vital organs. In selected patients, the only option may be radical resection and replacement by intestinal transplantation (ITx). We aimed to review all the current literature on ITx for FAP-related desmoids and provide an update from the largest single-center experience (2007-2024). All patients undergoing ITx for FAP-related desmoid were included. Between 2007 and 2024, 166 ITx was performed in 158 patients at Addenbrooke's Hospital, Cambridge, UK. Of these, 20 (12%) were for desmoid associated with FAP (10 modified multivisceral transplants, 8 isolated ITx and 2 liver-containing grafts). The five-year all-cause patient survival was 92%, median follow-up was 4.3 years. As the patients presented with very advanced disease, many technical challenges were faced such as: extensive ureteric involvement, abdominal wall fistulation, management of previously formed ileo-anal pouches and extra-abdominal recurrences. Graft selection was another evolving issue, as foregut resection- versus sparing techniques require careful preoperative risk stratification due to increased long-term cancer risk in FAP patients. For certain patients with advanced FAP/desmoid disease, ITx can allow for a radical resection with excellent survival and functional outcomes. However, there is a high degree of initial morbidity associated with the operation and patients should be appropriately counselled. Graft selection and degree of native organ resection requires a careful balanced discussion.

Allogeneic abdominal non-vascularized rectus fascia transplantation without immunosuppression equals syngeneic transplantation in a rabbit model at short-term follow-up

Complex abdominal wall repair remains a major surgical challenge. In transplant patients, non-vascularized rectus fascia (NVRF) is successfully used to bridge the defect. To extrapolate this to non-transplant patients, we developed a rabbit model of NVRF-transplantation without immunosuppression comparing syngeneic versus allogeneic transplants. Short-term outcome (4 weeks) was evaluated macroscopically (ingrowth, seroma/hematoma, herniation, and infection), histologically at the graft interface and center (inflammation, neovascularization, and collagen deposition) and by mechanical testing. In both groups a similar macroscopic ingrowth of the NVRF was observed. In the syn-group, one seroma and one hematoma was seen. Two small herniations were detected at the suture line in the allo-group. No surgical site infections were observed. Histologically, graft neovascularization was observed in all animals. Infiltration of T-lymphocytes was seen at the graft interface in both groups, but more in the allo-group (p < 0.0001). Deposition of collagen was not different between groups. Macrophages were present in both groups around sutures and in the center more abundantly in the allo-group (p = 0.0001). Graft stiffness and strength were similar for both groups. With this model, we showed that allogeneic transplantation without immunosuppression results in favorable short-term inflammatory and mechanical outcomes. Long-term experiments are needed to further evaluate the effect on graft integration and hernia development.

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.

Abdominal Wall Closure in Intestinal and Multivisceral Transplantation: A State-Of-The-Art Review of Vascularized Abdominal Wall and Nonvascularized Rectus Fascia Transplantation

Failure to close the abdomen after intestinal or multivisceral transplantation (Tx) remains a frequently occurring problem. Two attractive reconstruction methods, especially in large abdominal wall defects, are full-thickness abdominal wall vascularized composite allograft (AW-VCA) and nonvascularized rectus fascia (NVRF) Tx. This review compares surgical technique, immunology, integration, clinical experience, and indications of both techniques. In AW-VCA Tx, vascular anastomosis is required and the graft undergoes hypotrophy post-Tx. Furthermore, it has immunologic benefits and good clinical outcome. NVRF Tx is an easy technique without the need for vascular anastomosis. Moreover, a rapid integration and neovascularization occurs with excellent clinical outcome.

Treatment of Complex Desmoid Tumors in Familial Adenomatous Polyposis Syndrome by Intestinal Transplantation

Background

Desmoid tumors are fibroblastic lesions which often have an unpredictable and variable clinical course. In the context of familial adenomatous polyposis (FAP), these frequently occur intra-abdominally, especially in the small-bowel mesentery resulting in sepsis, fistulation, and invasion of the abdominal wall and retroperitoneum. In selected cases where other modalities have failed, the most radical option is to perform a total enterectomy and intestinal transplantation (ITx). In this study, we present our center's experience of ITx for desmoid in patients with FAP.

Methods

We performed a retrospective review of our prospectively collected database between 2007 and 2022. All patients undergoing ITx for FAP-related desmoid were included.

Results

Between October 2007 and September 2023, 144 ITx were performed on 130 patients at our center. Of these, 15 patients (9%) were for desmoid associated with FAP (7 modified multivisceral transplants, 6 isolated ITx, and 2 liver-containing grafts). The median follow-up was 57 mo (8-119); 5-y patient survival was 82%, all with functioning grafts without local desmoid recurrence. These patients presented us with several complex surgical issues, such as loss of abdominal domain, retroperitoneal/abdominal wall involvement, ileoanal pouch-related issues, and the need for foregut resection because of adenomatous disease.

Conclusions

ITx is a viable treatment in selected patients with FAP and extensive desmoid disease. The decision to refer for ITx can be challenging, particularly the timing and sequence of treatment (simultaneous versus sequential exenteration). Delays can result in additional disease burden, such as secondary liver disease or invasion of adjacent structures.

Innovative surgical techniques in the intestine and multivisceral transplant

PURPOSE OF REVIEW

This timely review delves into the evolution of multivisceral transplantation (MVT) over the past six decades underscoring how advancements in surgical techniques and immunosuppression have driven transformation, to provide insight into the historical development of MVT, shedding light on its journey from experimentation to a valuable clinical approach.

RECENT FINDINGS

The review presents contemporary enhancements in surgical methods within the context of intestinal transplantation. The versatility of MVT is emphasized, accommodating diverse organ combinations and techniques. Both isolated intestinal transplantation (IIT) and MVT have seen expanded indications, driven by improved parenteral nutrition, transplantation outcomes, and surgical innovations. Surgical techniques are tailored based on graft type, with various approaches for isolated transplantation. Preservation strategies and ostomy techniques are also covered, along with graft assessment advancements involving donor-specific antibodies.

SUMMARY

This review's findings underscore the remarkable evolution of MVT from experimental origins to a comprehensive clinical practice. The progress in surgical techniques and immunosuppression has broadened the spectrum of patients who can benefit from intestinal transplant, including both IIT and MVT. The expansion of indications offers hope to patients with complex gastrointestinal disorders. The detection of donor-specific antibodies in graft assessment advances diagnostic accuracy, ultimately improving patient outcomes.