Cryopreservation of Composite Tissue Transplants

Composite tissue allotransplantation holds great promise for upper extremity reconstruction but is limited by donor part availability. Cryopreservation may increase the availability of donor parts and even reduce antigenicity. The purpose of the study was to evaluate the viability of cryopreserved composite tissues and to demonstrate the feasibility of microvascular isotransplantation of cryopreserved composite flaps. Twenty epigastric flaps were harvested from Lewis rats. Ten flaps were analyzed fresh. Ten flaps were perfused with dimethyl sulfoxide (DMSO)/trehelose cryoprotectant agent (CPA), frozen by controlled cooling to −140°C, and stored for 2 weeks. Flaps were evaluated by factor VIII endothelial staining and MTT tetrazolium salt assay. For the in vivo phase, 30 flaps were harvested. Ten were transplanted fresh to isogenetic recipient animals, ten were perfused with CPA and transplanted, and ten were cryopreserved for 2 weeks, thawed, and transplanted. All cryopreserved samples displayed intact vascular endothelia on factor VIII staining. On MTT analysis, the epithelial viability index for the cryopreserved samples was not significantly different from fresh controls (p = 0.12). All freshly transplanted flaps (10/10) were viable at 60 days. Nine of ten flaps in the perfused/transplanted group were viable at 60 days. Survival of cryopreserved/transplanted flaps ranged from 5 to 60 days. The skin and vascular endothelial components of composite tissue flaps appear to retain their viability after cryopreservation. The in vivo studies demonstrate that the long-term survival of cryopreserved composite tissue transplants is feasible and support an indirect injury, rather than direct injury from freezing or cryoprotectant agents, as the mechanism of flap loss

Postmastectomy Radiation Therapy (PMRT) before and after 2-Stage Expander-Implant Breast Reconstruction: A Systematic Review

Background: In those undergoing treatment for breast cancer, evidence has demonstrated a significant improvement in survival, and a reduction in the risk of local recurrence in patients who undergo postmastectomy radiation therapy (PMRT). There is uncertainty about the optimal timing of PMRT, whether it should be before or after tissue expander or permanent implant placement. This study aimed to summarize the data reported in the literature on the effect of the timing of PMRT, both preceding and following 2-stage expander-implant breast reconstruction (IBR), and to statistically analyze the impact of timing on infection rates and the need for explantation. Methods: A comprehensive systematic review of the literature was conducted using the PubMed/Medline, Ovid, and Cochrane databases without timeframe limitations. Articles included in the analysis were those reporting outcomes data of PMRT in IBR published from 2009 to 2017. Chi-square statistical analysis was performed to compare infection and explantation rates between the two subgroups at p < 0.05. Results: A total of 11 studies met the inclusion criteria for this study. These studies reported outcomes data for 1565 total 2-stage expander-IBR procedures, where PMRT was used (1145 before, and 420 after, implant placement). There was a statistically significant higher likelihood of infection following pre-implant placement PMRT (21.03%, p = 0.000079), compared to PMRT after implant placement (9.69%). There was no difference in the rate of explantation between pre-implant placement PMRT (12.93%) and postimplant placement PMRT (11.43%). Conclusion: This study suggests that patients receiving PMRT before implant placement in 2-stage expander−implant based reconstruction may have a higher risk of developing an infection