Intraline® PDO Threads Cog Dimension 360 is a type of surgical thread used for lifting and realigning dermal tissue that has sagged or is drooping. Intraline® Cog Threads are polydioxanone (PDO) threads. These threads have barbs which hook onto the skin to provide support and lift the sagging tissue. It can produce fibrosis in the surrounding area to give rise to collagen. It is intended for facial lifting and skin firming. The threads have barbs or cogs that hook into the underside of the skin.