Which type of suture uses two needles threaded with opposite ends of the same thread and is permanently fixed at each end?

The type of suture that utilizes two needles threaded with opposite ends of the same thread and is permanently fixed at each end is the double intradermal suture. This technique is particularly beneficial in surgical procedures where a discreet closure is desired, as it allows the sutures to be placed parallel to the skin surface, reducing the visibility of the suture line.

In the double intradermal suture method, the needle is passed through the dermis at one end and comes out at the other, effectively allowing the thread to run under the skin, which provides support while also making for a neat, aesthetically pleasing closure. This suturing technique is often used in areas where minimal scarring is a priority, as it minimizes tension on the skin surface and helps in the cosmetic outcome of the wound.

The other options, while valuable suturing techniques, do not fit the description provided in the question. For instance, a single intradermal suture typically uses a single needle and thread, which would not achieve the objective of being fixed at both ends. A worm suture is a different type often used for securing tissue in place, and a continuous suture involves a single thread that runs continuously without interruptions rather than using separate threads at