Tiam Mana Saffari

34 CHAPTER 2 Figure 1. Schematic illustration of the components of a peripheral nerve. The peripheral nerve is depicted, demonstrating the axon protected by the endoneurium. The nerve fascicle is enveloped by the perineurium. Groups of fascicles are surrounded by the epineurium. Each fascicle of endo- neurium contains up to several thousands of axons. Blood is supplied by a network of capillary-like microvessels derived from arterioles and venules, which are branches of major limb vessels. The zoomed image depicts the close relationship of vessels and axons. When the nerve is injured, vascular endothelial cells guide the regeneration of peripheral nerve axons by producing vascular endothelial growth factor (VEGF, green dots) to induce angiogenesis preceding the repair of damaged nerves. With permission of the Mayo Foundation, Copyright Mayo Foundation 2019. All rights reserved. SEARCH STRATEGY Literature research was performed using PubMed, Medline, Cochrane, Web of Science and Google Scholar databases using the following combination of keywords: “angiogenesis” OR “vascularization” OR “blood perfusion” AND “nerve regeneration” OR “nerve graft” OR “nerve transplantation” until August 2019. The results were further screened by title and abstract to only present studies in peripheral nerve injuries in both animals and humans. Other inclusion criteria were articles (i) written in English, (ii) published in the last 35 years and (iii) that had available abstracts. Articles describing nerve studies in spinal cord surgery, facial and eye surgery were