Composite and Multivisceral Transplantation: Nomenclature, Surgical Techniques, Current Practice, and Long-term Outcome

Endovascular Treatment of a Multi-visceral Aortic Conduit Blowout With Parallel Stent Grafts and Coils

Multi-visceral transplantation (MVT) is a complex surgical procedure involving the transplantation of multiple abdominal organs as a single unit, typically used as bailout treatment of patients with devastating abdominal pathologies. Due to the complexity of the procedure, major and even life-threatening complications can happen. Vascular complications, including anastomotic breakdowns or pseudoaneurysms due to infections, can be universally lethal. Open surgical repair is often not an option due to the hostile operative field. We report a case of endovascular salvage of multi-visceral aortic conduit blowout utilizing parallel stent grafts and coils without sacrifice of the transplanted viscera. This combination can successfully control bleeding and maintain graft perfusion in this rare but devastating complication.

The role of endoscopy in the small intestinal transplant recipient: A review

Intestinal transplantation (ITx) is the treatment of choice for patients with intestinal failure who have developed life-threatening complications related to long-term parenteral nutrition. Patients may also undergo ITx as part of a combined liver-intestine or multivisceral transplant for a variety of indications, most commonly intestinal failure-associated liver disease or porto-mesenteric thrombosis. Endoscopy plays a critical role in the posttransplant management of these patients, most commonly in the diagnosis and management of rejection, which occurs in up to 30-40% of patients within the first-year posttransplant. With a lack of noninvasive biomarkers to identify the presence of rejection, endoscopy and biopsy remain the gold standard for its diagnosis. Endoscopic evaluation of the graft is also important in the identification of other complications post-ITx, including posttransplant lymphoproliferative disorder, graft-versus-host disease, and enteric infections. Each patient's posttransplant anatomy may be slightly different, making endoscopy sometimes technically challenging and necessitating clear and frequent communication with the surgical team in order to help identify the highest yield approach. Herein, we review the most common pathologies found endoscopically in the post-ITx patient and describe some of the unique challenges the endoscopist faces when evaluating these complex patients.

Mesentery - a 'New' organ

The mesentery is the organ in which all abdominal digestive organs develop, and which maintains these in systemic continuity in adulthood. Interest in the mesentery was rekindled by advancements of Heald and Hohenberger in colorectal surgery. Conventional descriptions hold there are multiple mesenteries centrally connected to the posterior midline. Recent advances first demonstrated that, distal to the duodenojejunal flexure, the mesentery is a continuous collection of tissues. This observation explained how the small and large intestines are centrally connected, and the anatomy of the associated peritoneal landscape. In turn it prompted recategorisation of the mesentery as an organ. Subsequent work demonstrated the mesentery remains continuous throughout development, and that abdominal digestive organs (i.e. liver, spleen, intestine and pancreas) develop either on, or in it. This relationship is retained into adulthood when abdominal digestive organs are directly connected to the mesentery (i.e. they are 'mesenteric' in embryological origin and anatomical position). Recognition of mesenteric continuity identified the mesenteric model of abdominal anatomy according to which all abdominal abdomino-pelvic organs are organised into either a mesenteric or a non-mesenteric domain. This model explains the positional anatomy of all abdominal digestive organs, and associated vasculature. Moreover, it explains the peritoneal landscape and enables differentiation of peritoneum from the mesentery. Increased scientific focus on the mesentery has identified multiple vital or specialised functions. These vary across time and in anatomical location. The following review demonstrates how recent advances related to the mesentery are re-orientating the study of human biology in general and, by extension, clinical practice.

Multivisceral transplant as an option to transplant cirrhotic patients with severe portal vein thrombosis

Non-tumoral portal vein thrombosis (PVT) is a critical complication in the patient with advanced cirrhosis awaiting liver transplantation (LT). With the evolution of liver transplant (LT) technique, PVT has morphed from an absolute contraindication to a relative contraindication, depending on the grade of the thrombus. The Yerdel classification is one system of grading PVT severity. Patients with Yerdel class 1-3 PVT can undergo LT at centers with experience in complex portal vein (PV) dissection, thrombectomy, and reconstruction. Class 4 PVT, however, is even more complex and may require heroic techniques such as cavoportal hemitransposition, PV arterialization or multivisceral transplant (MVT). Some centers use a MVT back-up approach for patients with Yerdel class 4 PVT. In these patients, all organs with PV outflow are procured simultaneously as a cluster graft from a deceased donor (liver, pancreas, intestine±stomach). If physiologic PV inflow is established intraoperatively, the recipient undergoes LT. Otherwise the MVT graft is transplanted. MVT establishes physiologic PV flow, but transplantation of the intestine confers significant lifelong risks including rejection, graft-versus host disease and post-transplant lymphoma. Yerdel class 1-4 PVT patients undergoing successful LT have 5-year survival similar to non-PVT patients, while patients requiring full MVT experience somewhat higher mortality because of the complexity of the surgery and medical management.