 OIS is very similar to conventional interrupted intradermal suture IS, except that the suture in OIS is canted or angled relative to the vertical plane. To perform OIS, the needle is passed from deep to superficial dermis and canted 30-60 from the normal vertical plane. The needle is then inserted into the opposite wound edge from superficial to deep dermis in a mirror-image fashion. The thread is tied with a square knot to finish the suture. The key characteristic that distinguishes OIS from IS is that OIS involves suturing on an angle to the vertical plane and IS involves suturing on the vertical plane. 