GENERAL SPECIFICATIONS OF SURGICAL STITCHING MATERIALS
Surgical stitching materials are used to provide tissue support during wound healing process through approximation of two edges of the wound. Although wound healing is a natural process, severed damages need to be approximated via surgical suture materials. Surgical thread is the most common material for wound closure for a long time. There are two significant factors affecting surgical stitching process: Surgical needle and surgical suture.
Surgical needle is required for penetration of surgical thread into tissue. Minimal tissue trauma is mostly expected from a surgical needle during carrying of surgical suture through tissue. Although eyed needles were used in the past, atraumatic needles have been widely used now since eyed needles result in big gaps in tissue during tissue penetration and suture is pulled strongly through tissues. Therefore, tissue trauma is seen at minimum level with atraumatic needles. Ideal surgical needle should have following specifications:
- It should be made of high quality stainless steel material.
- It should be stable when it is held by needle-holder.
- It should not cause any tissue trauma during tissue penetration.
- It should be rigid enough not to bend but should be flexible enough not to be broken.
- It should have corrosion resistance and be sterile in order to prevent tissue from entrance of foreign materials and microorganisms, respectively.
- It should have smooth surface and should have coating material to penetrate into tissue easily. Needle surface should have resistance to corrosion.
- It should have similar diameters with the suture attached to it.
There are three main factors providing the specifications of ideal needle: metal alloy, geometry and coating material. Surgical needles are made of stainless steel. An ideal needle should have at least 12% chromium in its metal composition. Chromium provides resistance to oxygen by making a chromium oxide layer on the surface. Nickel composition is another important factor which prevents needle bending and needle break. Needles made from stainless steel grade AISI 302 have 8-10% nickel and 17-19% chromium composition. Thus, they are more resistant than the needles manufactured from stainless steel grade AISI 455 and AISI 420 and. There are three main components determining needle geometry:
- The eye
- The body
- The point
During selection of surgical needle, it is important to determine the measurements of these three components and they are all related to efficient use of needle.