The goal of this observational study is to learn about endothelial damage in major spine surgery, expressed as rise in circulating Syndecan-1. The main questions it aims to answer are: * What is the extent of endothelial glycocalyx shedding in major spine surgery? * Are there differences in different type of surgical populations? (adolescent idiopathic scoliosis, adult degenerative spine disease, oncologic surgery) To do so, blood samples will be drawn from participants at the following timepoints: * basal * after surgery * if transfusion of Fresh Frozen Plasma: before and after transfusion * Post-Operative Day 1-2-4