Материал: Руководство+к+тренажеру+_завязывание+узлов_

Surgical Needles

Necessary for the placement of sutures in tissue, surgical needles must be designed to carry suture material through tissue with minimal trauma. They must be sharp enough to penetrate tissue with minimal resistance. They should be rigid enough to resist bending, yet flexible enough to bend before breaking. They must be sterile and corrosion-resistant to prevent introduction of microorganisms or foreign bodies into the wound.

To meet these requirements, the best surgical needles are made of high quality stainless steel, a noncorrosive material. Surgical needles made of carbon steel may corrode, leaving pits that can harbor microorganisms. All ETHICON* stainless steel needles are heat-treated to give them the maximum possible strength and ductility to perform satisfactorily in the body tissues for which they are designed. ETHALLOY* needle alloy, a noncorrosive material, was developed for unsurpassed strength and ductility in precision needles used in cardiovascular, ophthalmic, plastic, and microsurgical procedures.

Ductility is the ability of the needle to bend to a given angle under a given amount of pressure, called load, without breaking. If too great a force is applied to a needle it may break, but a ductile needle will bend before breaking. If a surgeon feels a needle bending, this is a signal that excessive force is being applied. The strength of a needle is determined in the laboratory by bending the needle 900; the required force is a measurement of the strength of the needle. If a needle is weak, it will bend too easily and can compromise the surgeon?s control and damage surrounding tissue during the procedure.

Regardless of ultimate intended use, all surgical needles have three basic components: the attachment end, the body, and the point.

The majority of sutures used today have appropriate needles attached by the manufacturer. Swaged sutures join the needle and suture together as a continuous unit that is convenient to use and minimizes tissue trauma. ATRALOC* surgical needles, which are permanently swaged to the suture strand, are supplied in a variety

of sizes, shapes, and strengths. Some incorporate the CONTROL RELEASE* needle suture principle which facilitates fast separation of the needle from the suture when desired by the surgeon. Even though the suture is securely fastened to the needle, a slight, straight tug on the needleholder will release it. This feature allows rapid placement of many sutures, as in interrupted suture techniques.

The body, or shaft, of a needle is the portion which is grasped by the needleholder during the surgical procedure. The body should be as close as possible to the diameter of the suture material. The curvature of the body may be straight, half-curved, curved, or compound curved. The cross-sectional configuration of the body may be round, oval, side-flattened rectangular, triangular, or trapezoidal. The oval, side-flattened rectangular, and triangular shapes may be fabricated with longitudinal ribs on the inside or outside surfaces. This feature provides greater stability of the needle in the needleholder.

The point extends from the extreme tip of the needle to the maximum cross-section of the body. The basic needle points are cutting, tapered, or blunt. Each needle point is designed and produced to the required degree of sharpness to smoothly penetrate the types of tissue to be sutured.

Surgical needles vary in size and wire gauge. The diameter is the gauge or thickness of the needle wire. This varies from 30 microns (.001 inch) to 56 mil (.045 inch, 1.4 mm). Very small needles of fine gauge wire are needed for micro-surgery. Large, heavy gauge needles are used to penetrate the sternum and to place retention sutures in the abdominal wall. A broad spectrum of sizes are available between these two extremes.

Of the many types available, the specific needle selected for use is determined by the type of tissue to be sutured, the location and accessibility, size of the suture material, and the surgeon's preference.

Practice Board

Practice Board*

The KNOT TYING MANUAL and practice board are available from ETHICON, INC., without charge for all learners of suturing and knot tying techniques.

*Contributing Designer-Bashir Zikria, MD, FACS