An overlying vertical mattress suture of 9-0 nylon, running the length of the conjunctival edge and anchored to an intact limbus at each end, allows very leak-resistant closure of fornix-based conjunctival flaps. Use of a taper needle with a tiny cutting tip prevents leakage at suture holes. The distance between suture holes in the conjunctival flap must be less than the length of the corresponding limbal anchor bite to hold the conjunctival edge flat where the suture does not overlie the edge. In 153 operations using mitomycin C intraoperatively, one of 78 eyes that had undergone primary trabeculectomy or cataract-trabeculectomy surgery and 18 of 75 eyes that had undergone trabeculectomy after other surgeries had temporary leaks along the suture line, but only two of these leaks persisted and required surgical repair. This technique allows filtration surgery to be performed in areas of scarred or recessed conjunctiva that are not suitable for limbus-based flaps.
Wise JB. Mitomycin-Compatible Suture Technique for Fornix-Based Conjunctival Flaps in Glaucoma Filtration Surgery. Arch Ophthalmol. 1993;111(7):992-997. doi:10.1001/archopht.1993.01090070112029