No abstract

Cell-based therapies exploit the heterogeneous and self-sufficient biological environment of stem cells to restore, maintain and improve tissue functions. Adipose-derived stem cells (ASCs) are, to this aim, promising cell types thanks to advantageous isolation procedures, growth kinetics, plasticity and trophic properties. Specifically, bone regeneration represents a suitable, though often challenging, target setting to test and apply ASC-based therapeutic strategies. Areas covered: ASCs are extremely plastic and secrete bioactive peptides that mediate paracrine functions, mediating their trophic actions in vivo. Numerous preclinical studies demonstrated that ASCs improve bone healing. Clinical trials are ongoing to validate the clinical feasibility of these approaches. This review is intended to define the state-of-the-art on ASCs, encompassing the biological features that make them suitable for bone regenerative strategies, and to provide an update on existing preclinical and clinical applications. Expert opinion: ASCs offer numerous advantages over other stem cells in terms of feasibility of clinical translation. Data obtained from in vivo experimentation are encouraging, and clinical trials are ongoing. More robust validations are thus expected to be achieved during the next few years, and will likely pave the way to optimized patient-tailored treatments for bone regeneration.

Background Interposition vein grafts (IVG) and vascular bridge flaps (VBF) have been exploited as vascular conduit in challenging head and neck reconstructions. Methods A retrospective review was conducted on 6025 flaps. The effect of patients' characteristics and length of IVG on flap compromise and loss were analyzed. Comparison between IVG and VBF was performed. Results The flap compromise and loss rates for the overall group were 8.2% and 3.2%, respectively. An IVG was used in 309 free flaps. The average length of the vein grafts was 6.9 ± 4.2 cm. An unplanned return to the operation room occurred in 32 cases (10.4%) and failure of the flap in 12 patients (3.9%). Binary logistic regression found a significant association between flap compromise and loss rates and length of IVG, hypertension, prior radiation, and neck dissection. In the multiple regression model, length of IVG and prior radiation significantly influenced the outcomes. Thirty‐nine patients underwent reconstruction with a long IVG (>10 cm). Twenty‐six patients underwent surgical reconstruction with radial forearm flap as a VBF. The rate of flap compromise was higher in the group with a long IVG (P = .01). Conclusions In head and neck free flap reconstruction, the length of IVGs and history of radiotherapy are associated with flap compromise and loss. In case of long distance between the pedicle and the recipient site, the use of a VBF bridge should be considered as a safe alternative.