Successful 18‐hour acellular extracorporeal perfusion and replantation of porcine limbs Histology versus nerve stimulation

Background The current standard for composite tissue preservation is static cold storage (SCS) and is limited to 6h until irreversible muscle damage occurs. Extracorporeal perfusion (ECP) is a promising technique for prolonged preservation, however, functional results have been scarcely researched. This article assessed neuromuscular function and compared results to histological alterations to predict muscle damage after ECP. Methods Forelimbs of twelve Dutch landrace pigs were amputated and preserved by 4h SCS at 4-6°C (n=6) or 18h mid-thermic ECP with University of Wisconsin solution (n=6). Limbs were replanted and observed for 12h. Sham surgery was performed on contralateral forelimbs (n=12). Histology analysis scored four sub-groups representing different alterations (higher score equals more damage). Results Muscle contraction after median nerve stimulation was comparable between ECP, SCS, and sham limbs (p=0.193). Histology scores were higher in ECP limbs compared to SCS limbs (4.8 vs 1.5, p=0.013). This was mainly based on more oedema in these limbs. Conclusion In-vivo muscle contraction was well preserved after 18h ECP compared to short SCS, although histology seemed inferior in this group. Histology, therefore, did not correlate to muscle function at 12hr after replantation. This leads to the question whether histology or neuromuscular function is the best predictor for transplant success.