Development of a New Flat Needle and a Reduced Surface Coating Thread for Endoscopic Suturing

Background: Intracorporeal suturing during endoscopic surgery is a difficult procedure. The curved needle is the most difficult to position properly within the jaws of the needle driver. The low friction suture materials exhibit good knot run-down, but at the expense of increased tendency for slipping. It is therefore necessary to invent a new needle and a new thread to facilitate intracorporeal suturing. Materials and methods: We made a new flat needle (F-needle) to facilitate grasping and a new reduced silicone-coated thread to prevent the knots from loosening. The time required to grasp the F-needle and the round needle (R-needle) by 10 surgeons was measured. The angle between the needle and the needle driver was measured. The minimum number of intertwining knots required for the knot to hold was counted, and the minimum number of superimposed knots that prevented the knots from coming undone when the testing machine attempted to release them was counted. Results: The F-needle was grasped in less time than the R-needle. The error in yaw angle with the F-needle was smaller than in the R-needle. The minimum number of knots needed to hold against the untying force with the reduced silicone-coated thread was less than with the conventional silicone-coated thread. Conclusions: The new flat needle was grasped more accurately and quickly than the round needles, and the thread with reduced surface coating was less likely to loosen. Therefore, the combination of the new flat needle and thread with reduced surface coating is useful for endoscopic suturing.