BACKGROUND: A critical barrier to successful limb replantation and allotransplantation is the maximum allowable limb ischemia time of 4 to 6 hours. The current gold standard is to preserve amputated limbs on an ice slurry. Experimental machine perfusion has yielded promising results as an alternative. In particular, hypothermic acellular perfusion has enabled preservation of amputated limbs for up to 12 hours thus far. METHODS: Amputated forelimbs of Yorkshire pigs were preserved on static cold storage at 4°C for 4 hours (static cold storage group) or perfused at 8°C for 24 hours (perfusion group) with oxygenated modified STEEN Solution perfusate before replantation. Animals were followed up for 7 days after replantation. RESULTS: Eight animals underwent replantation (cold storage group, n = 4; perfusion group, n = 4). Seventy-five and 100 percent of animals in the static cold storage and perfusion groups survived for 7 days, respectively. Glycogen and adenosine triphosphate remained stable throughout perfusion. Heart and respiratory rate after replantation were increased in the static cold storage group. There was increased damage in muscle biopsy specimens obtained from animals in the static cold storage group after 7 days when compared with those from animals in the perfusion group. CONCLUSIONS: Hypothermic acellular ex vivo perfusion of limbs for up to 24 hours enables tissue preservation comparable to that obtained with conventional static cold storage for 4 hours and may reduce muscle damage and systemic reactions on limb replantation. Translation to human limbs may help improve limb replantation and allotransplantation outcomes.
