SEMA3A and ossification of the posterior longitudinal ligament of the spine: Focusing on angiogenesis as a central theme, this review systematically summarizes the mechanisms by which key molecules, including LOXL2, Sema3A, integrin αVβ3, ANGPT2, IL-6, TGF-β, the <i>ACE</i> D/D polymorphism, and YAP, mediate the coupling of angiogenesis and osteogenesis in OPLL.