Construction of a Composite Regenerative Peripheral Nerve Interface in a Rat Model of Nerve Injury

Take an anesthetized rat with the thigh’s common peroneal nerve transected to model peripheral nerve injury during limb amputation.

Place a muscle graft from a donor rat over the exposed thigh muscle. The graft’s center lacks the outermost muscle covering, exposing muscle fibers for nerve attachment.

Secure the transected nerve end to the exposed fibers and anchor the graft to the underlying muscle.

Suture the nerve to the muscle graft to minimize mechanical strain.

Position the donor rat’s skin graft, which consists of the dermis layer, over the nerve.

Suture the skin graft to the muscle graft.

This composite regenerative peripheral nerve interface, or C-RPNI, supports nerve regeneration.

Close the wound, disinfect the site, apply antibiotics to prevent infection, and allow recovery.

Over time, motor neurons reinnervate the muscle to form neuromuscular junctions, while sensory neurons extend into the skin graft to reestablish sensory structures.

To fabricate the C-RPNI construct, place the muscle graft under the dissecting microscope and remove all of the central tendinous tissue as well as a small central segment of epimysium leaving the tendinous ends intact. Using an 8-0 nylon suture and two interrupted stitches, secure the epineurium of the transected end of the common peroneal nerve to the area of the muscle graft devoid of epimysium on either side of the nerve.

Secure the muscle graft to the femur periosteum with a single 6-0 nylon interrupted stitch both proximally and distally with the nerve muscle junction facing away from the femur. Place an 8-0 nylon stitch at the inferior central margin of the muscle graft epimysium securing it to the common peroneal nerve epineurium so as to create laxity in the nerve within the muscle graft. Position the skin graft on the muscle graft so that it completely covers the nerve and the majority of the muscle with the deep margin of the dermis resting on the muscle.

Trim any dermis that extends beyond the border of the muscle and use 8-0 nylon interrupted sutures to circumferentially secure the skin graft to the muscle graft. Close the biceps femoris fascia over the construct in a running fashion with 5-0 chromic suture and close the overlying skin with a 4-0 chromic suture in running fashion. Then swap the surgical area with an alcohol pad and apply antibiotic ointment before allowing the rat to recover with food and water sources separate from cage mates with monitoring until full recumbency.