Novel technique for innervated abdominal wall vascularized composite allotransplantation: a separation of components approach

Abstract

Objective: Applications for Abdominal Wall Vascularized Composite Allotransplantation may expand if a functional graft with decreased immunosuppressive requirements can be designed. We hypothesize that it is anatomically feasible to prepare a functional, innervated, and vascularized abdominal composite graft using a multilayered component separation technique. Including vascularized bone in the graft design may decrease the immunosuppressive requirements by inducing immunologic chimerism.

Methods: Two cadaver torsos were used. Adipocutaneous flaps were elevated from the midaxillary lines, preserving deep inferior epigastric artery perforators. A 2-layered component separation through the external and internal oblique fasciae was carried out, exposing segmental intercostal thoracolumbar nerves. Superiorly directed muscle release over the subcostal margin provided for a 3-rib segment with attached rectus abdominis muscle. The remainder of the full-thickness allograft was harvested with its vasculature. Flap inset into the recipient cadaver abdomen, with osteosynthesis fixation between donor and recipient ribs, was achieved.

Results: The harvested grafts had an average size of 845 ± 205 cm(2) with a total procurement time of 110 minutes. On one cadaver, 4 thoracolumbar nerves were isolated bilaterally, while the other cadaver yielded 3 nerves. The nerves were transected with an average length of 5.7 ± 1.2 cm. The graft vasculature was transected with a length of 4.40 ± 0.10 cm.

Conclusion: Using the principles of component separation technique, we demonstrated a novel approach to harvest and transfer a neurotized osteomyofasciocutaneous abdominal wall allotransplant as a multipedicled, single functional unit.

Keywords: abdominal wall transplantation; chimerism; component separation; hernia; vascularized composite allotransplantation.

Figure 1

Hexagonal AW-VCA incisional outline indicated by blue markings.

Figure 2

Adipocutaneous skin flaps elevated in a lateral to medial direction.

Figure 3

Deep inferior epigastric perforators (Huger Zone I) are preserved during skin flap elevation.

Figure 4

External oblique fascia with semilunar line indicated by dotted line. This is the site of the first layer component separation.

Figure 5

First layer component separation completed exposing internal oblique layer.

Figure 6

Demarcation of second stage of component separation 2 cm lateral to semilunar line.

Figure 7

Segmental intercostal thoracolumbar nerves identified between the internal oblique and transversus abdominis muscle layer.

Figure 8

Left sided dissection complete, and skin flap elevation on the right.

Figure 9

Rectus abdominis muscle attachment to lowermost ribs.

Figure 10

Release of 3 vertebrochondral ribs with attached rectus abdominis muscle.

Figure 11

Complete release of vertebrochondral ribs with observable marrow.

Figure 12

Full-thickness dissection of graft continued through the peritoneal cavity.

Figure 13

Graft was reflected in a cranial to caudal manner to identify and preserve the deep inferior epigastric pedicle indicated by the arrows. These pedicles provide the main blood supply to the graft.

Figure 14

Dissection of the deep inferior epigastric pedicles.

Figure 15

Graft transferred to recipient cadaver illustrating the potential nerve coaptation and bone synthesis.

Figure 16

Simulated osteosynthesis between donor and recipient ribs using fixation plate and screws.