Tiam Mana Saffari

254 CHAPTER 12 SUMMARY Enhancing decellularized nerve allograft to equal autograft performances has been an ongoing challenge for surgeons and nerve scientists. This thesis is part of a research collaboration with the Mayo Clinic (MN, USA) and builds on the results of previously conducted research, leading to this thesis called “Augmentation of nerve allografts with angiogenesis and stem cells” . The hypothesis of this thesis was if augmentation of decellularized nerve allograft environment with angiogenesis and stem cells improves nerve regeneration and revascularization. In Chapter 1 a general introduction on peripheral nerve injury and reconstruction including a historical background of the research line and an overview of the specific aims of this thesis is provided. PART I: THE ROLE OF ANGIOGENESIS IN NERVE REGENERATION In Part I, the role of angiogenesis in nerve regeneration has been investigated, represented by Chapter 2-7. The review in Chapter 2 details the role of vascularization in nerve regeneration of nerve grafts including all relevant publications until August 2019. The processes underlying the formation of blood vessels are described and an overview of the effect of vascularization on nerve regeneration in basic science and clinical applications is provided. Nerve characteristics such as length of the gap, nature of the nerve (e.g. motor nerves, mixed motor and sensory nerves, or sensory nerves) and the regeneration rate per animal were found to cause difficulty in comparison. In clinical studies, outcomes were strongly correlated with the time course and degree of denervation. Well-designed clinical studies comparing vascularized nerve grafts (VNG) to non-vascularized nerve grafts (NVNG) remain lacking and existing studies are inconclusive. Although VNGs have the potential to improve nerve reconstruction after injury, the surgeries are demanding and require microvascular experience. The conclusions suggest that technical obstacles could be overcome by provision of vascularized flaps that may enhance revascularization of reconstructed peripheral nerve injuries. In Chapter 3 , the surgical technique for the superficial inferior epigastric artery fascial (SIEF) flap has been described that provides vascularization to the nerve bed. Outcomes demonstrated a total success rate of SIEF flap viability without necrosis at 12 and 16 weeks, providing evidence that this flap is durable and could be used for future