Role of “reduced-size” liver/bowel grafts in the “abdominal wall transplantation” era

Intestinal and Multivisceral Transplantation: Indications and Surgical Techniques

Intestinal transplantation and multivisceral transplantation are technically challenging and complex procedures mainly performed on patients with irreversible and non-medically manageable end-stage intestinal failure. Increasingly, other organs besides small intestines are included in the allograft for which the terms "composite intestinal transplantation" and "multivisceral transplantation" are used. Commonly, complex vascular reconstructions are used for these procedures. Knowledge of surgical anatomy hence is essential for accurate interpretation of postoperative imaging in these patients. This article reviews the indications and most common surgical techniques for intestinal and multivisceral transplantations.

Intestinal Donation and Utilization: Single-Center Analysis Within Eurotransplant

Intestinal donor criteria are classically kept strict, thereby limiting donor supply. Indications for intestinal transplantation (ITx) are rare, but improved outcome and new emerging indications lead to increased demand and relaxing donor criteria should be considered. We sought to compare the donor criteria of intestines transplanted at our center with predefined (per protocol) criteria, and to determine how relaxing donor criteria could impact the potential donor pool. Donor criteria used in 22 consecutive ITx at our center between 2000 and 2020 were compared with predefined criteria. Next, multiorgan donors effectively offered by our Donor Network to Eurotransplant between 2014 and 2020 were retrospectively screened, according to predefined and effectively used intestinal donation criteria. Finally, utilization rate of offered intestines was calculated. In our ITx series, the effectively used donor criteria were less strict than those initially predefined. With these relaxed criteria, a favorable 5-year graft/patient survival of 75% and 95%, respectively was reached. Applying these relaxed criteria would lead to a 127% increase in intestinal offers. Paradoxically, 70% of offered intestines were not used. In conclusion, a significant increase in intestinal donation could be obtained by relaxing donor criteria, while still achieving excellent outcome. Offered intestines are underutilized.

Using Radiographic Domain for Evaluating Indications in Abdominal Wall Transplantation

BACKGROUND

There is currently no description of abdominal domain changes in small bowel transplantation population or consensus of criteria regarding which patients are at high risk for immediate postoperative abdominal wall complications or would benefit from abdominal wall vascularized composite allotransplantation.

METHODS

A retrospective chart review was performed on 14 adult patients receiving intestinal or multivisceral transplantation. Preoperative and postoperative computed tomography scans were reviewed, and multiple variables were collected regarding abdominal domain and volume and analyzed comparing postoperative changes and abdominal wall complications.

RESULTS

Patients after intestinal or multivisceral transplantation had a mean reduction in overall intraperitoneal volume in the immediate postoperative period from 9031 cm3 to 7846 cm3 (P = 0.314). This intraperitoneal volume was further reduced to an average of 6261 cm3 upon radiographic evaluation greater than 1 year postoperatively (P = 0.024). Patients with preexisting abdominal wound (P = 0.002), radiation, or presence of ostomy (P = 0.047) were significantly associated with postoperative abdominal wall complications. No preoperative radiographic findings had a significant association with postoperative abdominal wall complications.

CONCLUSIONS

Computed tomography imaging demonstrates that intestinal and multivisceral transplant patients have significant reduction in intraperitoneal volume and domain after transplantation in the acute and delayed postoperative setting. Preoperative radiographic abdominal domain was not able to predict patients with postoperative abdominal wall complications. Patients with abdominal wounds, ostomies, and preoperative radiation therapy were associated with acute postoperative abdominal complications and may be considered for need of reconstructive techniques including abdominal wall transplantation.

Indications of Intestinal Transplantation

"The intestinal transplantation is reserved for patients with life-threatening complications of permanent intestinal failure or underlying gastrointestinal disease. The choice of the allograft for a particular patient depends on several factors and the presence of concurrent organ failure, and availability of the donor organs, and specialized care. Combined liver and intestinal transplant allows for patients who have parenteral nutrition-associated liver disease a possibility of improved quality of life and nutrition as well as survival. Intestinal transplantation has made giant strides over the past few decades to the present era where current graft survivals are comparable with other solid organ transplants."

Abdominal wall transplantation in organ transplantation: Our experience

Abdominal wall transplantation has been consolidated as an alternative to primary abdominal wall closure in intestinal and multiple organ transplant recipients. Given that it is feasible to obtain the visceral graft and the abdominal wall graft from the same donor, abdominal wall transplantation could offer satisfactory outcomes and be easily coordinated. Non-vascularized fascia is one of the alternatives for abdominal wall closure in transplantation. We report two cases of non-vascularized fascia transplantation in intestinal and multivisceral transplants, respectively. Both donors were young (23 and 18 years old). Both recipients had endured multiple previous surgeries, and no surgical alternatives for primary wall repair could be offered. In both cases, a complete abdominal wall flap was retrieved from the donor, however, due to the characteristics of the recipient's abdominal wall defect, only non-vascularized fascia was used after removing skin and subcutaneous cellular tissue from the graft. Abdominal wall transplantation is an option to consider for abdominal wall closure in patients with multiple previous surgeries and no alternatives for primary wall repair.

Abdominal Wall Transplant Surgery

The evolution and success of intestinal and multi-visceral transplantation over the past 20 years have raised the issue of difficult or even impossible abdominal closure, a topic rarely encountered in other fields of transplantation. Different techniques have been proposed to address this topic. The choice depends on the transplant team's expertise and/or the availability of a plastic surgery service. Abdominal wall transplant is a type of composite tissue allograft that can be utilized to reconstitute the abdominal domains of patients who undergo intestinal transplant, and the results are encouraging. It is an effective option to achieve primary abdominal closure after intestinal transplant. In its full-thickness form, it may be useful for monitoring rejection or viability of visceral organs. Our aim is to review the role of abdominal wall transplant in achieving tension-free closure of the abdomen.

Small-for-size Syndrome Does Not Occur in Intestinal Transplantation Without Liver Containing Grafts

BACKGROUND

The ideal donor in intestinal transplantation (ITX) is generally considered to be 50% to 70% of recipient body weight. This may be due to concerns for "small for size" syndrome as seen in liver transplantation. We report our experience using smaller donors (donor-recipient weight ratio [DRWR], < 50%) in ITX recipients.

METHODS

We studied a group of ITX recipients with DRWR of 50% or less to unmatched controls who received intestinal allografts with DRWR greater than 50%. We examined patient and graft survival and enteral autonomy from parenteral nutrition as surrogate markers for safety of using smaller donors and ease of abdominal wall closure between groups to determine the value.

RESULTS

There was no difference in overall patient and graft survival, time to enteral autonomy from parenteral nutrition, and weight gain after ITX over time between groups. The need for complicated abdominal closure techniques was significantly more frequent in the control group than in the study group (34.6% vs 6.9%, P = 0.01). Secondary abdominal closure occurred more frequently in the control group (15.4% vs 0%, P = 0.014). Wound revisions also occurred more frequently in the control group (15.4% vs 0%, P = 0.028).

CONCLUSIONS

Our data suggest that ITX using smaller donors (DRWR ≤ 50%) seems to be an acceptable practice without adverse impact on surgical complications, nutritional autonomy, and patient and graft survival. Abdominal wall closure seems easier in recipients of smaller donors and "small for size" syndrome as described in liver transplantation does not occur with intestinal allografts.