THz Vacuum devices require high precision technological processes, but fabrication tolerances could highly affect the overall performances. Therefore a statistical analysis is fundamental for a reliable design. In this abstract, it is proposed a study on a Corrugated Waveguide Slow-Wave Structure for Traveling Wave Tubes in the THz region. An analytical model is validated by three dimensional electromagnetic softwares, both for cold and hot parameters. The proved accuracy and fast computation time make the model suitable for the sensitivity analysis of the structure.