However, in the OPLL, inflammatory cytokines such as IL-1β, IFN-γ, TNF-α, and TNF-β in the tissue were not significantly different in NOPLL and OPLL patients in the current study (Figure 2 and Figure 3), nor were they higher than the level in the serum. Here, LTA is linked to ossification of the posterior longitudinal ligament of the spine.