Procurement for a Vascularized and Reinnervated Abdominal Wall Allotransplantation

Our French laboratory is focused on enhancing VCA to improve harvest protocols, optimize graft preservation, strategy to reduce ischemia reperfusion injury, and induce human tolerance.

The main current challenges in VCA includes standardizing procurement methods and developing robust protocolized tissue preservation techniques to ensure graft viability and improve long-term functional and immunological outcomes. This protocol is intended for teams specializing in VCA to help them perform optimized abdominal allotransplantations in a reliable and reproductible way. Unlike other techniques, this protocol provides a step by step guide to procuring a reinnervated abdominal wall transplant, which is key for optimal functional recovery.

Our French reconstructive department focuses on enhancing nerve regeneration, a growing field using techniques, like TMR, APNI and nerve conduits. This is especially relevant during the transplantation step of this graft.

Our protocol raises key questions about how many nerve repairs are needed and which techniques to use to achieve meaningful motor reinnervation and functional recovery.

Our lab will focus on graft preservation, which is the key to a successful transplantation, and this protocol could be a very useful model if harvested on a dead bred donor, but it has to be done under strict research authorization.

[Instructor] To begin, position the patient supine on the surgical table with the arms alongside the body. Use a dermographic pencil to draw the superior boundary line starting at the xiphoid process of the sternum. Extend this line laterally, tracing the inferior margin of the rib cage on both sides until it reaches a vertical line situated two to three centimeters lateral to the anterior superior iliac spine. Define the lateral boundary with a vertical line positioned two to three centimeters lateral to the anterior superior iliac spine. From this point, draw a downward line to reach the femoral artery pulse located approximately seven to 10 centimeters below the inguinal ligament. Next, draw the inferior boundary by extending a line from the femoral artery pulse toward the pubic spine on each side. Connect both sides of the drawing along the midline, ending at the pubic synthesis to complete the triangular outline. Perform a bilateral subcostal skin incision along the previously marked line using a cold scalpel blade. Then, using an electrocautery device, incise through the subcutaneous tissue until reaching the muscular fascia. Incise the fascia overlying the rectus abdominis muscles to expose the underlying muscle bodies and transect the costal insertions of the rectus abdominis muscles with the electrocautery device. Now identify the superior epigastric vessels behind the rectus muscles, ligate them carefully, and section them with the electrocautery behind each mobilized rectus muscle, incise the deep muscular aponeurosis, then the transversalis fascia, and finally, the parietal peritoneal fascia. Laterally dissect the external oblique muscles to expose and identify the semilunar line. Perform a skin incision with a cold scalpel blade following the previously marked lateral boundary. Use an electrocautery device to continue the incision through the subcutaneous tissue until the aponeurotic layer of the external oblique muscles is reached. Next, incise the external oblique muscle followed by the internal oblique muscle, maintaining a lateral margin of two to three centimeters from the semilunar line. Then, locate the thoracolumbar nerves between the internal oblique and transverse abdominis muscles, and carefully dissect these nerves laterally as far as possible to preserve them. Once the thoracolumbar nerves are secured, incise the transverse abdominis muscle followed by the transversalis fascia, and then the parietal peritoneal fascia. While releasing the allograft, identify the deep inferior epigastric pedicles located on the deep surface of the rectus abdominis muscles. Make a skin incision along the lower design using a cold scalpel blade. Using an electric scalpel, continue the dissection through the subcutaneous tissue until reaching the crural muscular aponeurotic plane of the thigh. Now identify the great saphenous vein, ligate and transect it. Then locate the lateral femoral cutaneous nerve and transect it. Incise the crural fascia, ensuring it is included in the graft specimen. Next, elevate the two triangular fascia cutaneous flaps located beneath the inguinal ligaments until the femoral vessels are exposed. On both sides, carefully dissect the femoral artery and vein, along with their collateral branches, including the superficial inferior epigastric and superficial circumflex iliac vessels. Continue the dissection toward the external iliac artery and vein, identifying and preserving the deep inferior epigastric and deep circumflex iliac vessels. Then, loop the deep inferior epigastric vessels with a silicone loop for protection. To continue the dissection above the inguinal ligament, remove the muscular fascia over the iliac muscle to avoid damaging the deep circumflex iliac vessels. Using an electric scalpel, detach the rectus abdominis muscles from their pubic insertions, ensuring the deep inferior epigastric vessels remain intact. Next, ligate and transect the contents of the inguinal canal, including the round ligament of the uterus and ilioinguinal nerve in women. To complete the dissection, ligate and cut the deep circumflex iliac, superficial circumflex iliac, and superficial inferior epigastric vessels at their origins on the external iliac and femoral vessels. Ensure the two deep inferior epigastric vascular pedicles remain attached to both the abdominal wall allograft and the donor's body. After removing the abdominal viscera, identify and mark the deep inferior epigastric vessels on both sides, typically one artery and two veins per side. Carefully dissect and ligate these vessels at their origins from the external iliac vessels, and then transect the vessels to release the graft. Now catheterize each deep inferior epigastric artery using a vascular cannula equipped with a stopcock and secure it to the arterial lumen with a ligature. Finally, attach an irrigation set to the cannulas and flush the graft with one to three liters of University of Wisconsin preservation solution tempered at four degrees Celsius. Maintain a flow rate of approximately 100 milliliters per minute under low pressure, not exceeding 100 millimeters of mercury until the effluent runs clear. The average usable length of the thoracolumbar nerves dissected from both right and left sides was 68 millimeters with individual nerve lengths ranging from 60 to 85 millimeters. The deep inferior epigastric artery measured 85 millimeters on the left, and 71 millimeters on the right before entering the graft.