Surgery requires the use of several different types of needles. Needles need to be strong enough to pass through tough tissue while causing minimal trauma to delicate tissues and reducing tissue reactions. Needles are made of steel, come in different sizes, have blunt or sharp points, and can be curved or straight.
Straight needles are used for skin closure in some surgeries. Straight needles can be used for suturing without requiring the use of a needle holder, as long as the suturing area offers good visibility.
Curved needles are the most commonly used surgical needles. Curved needles are made in several different configurations, including half-curved (previously used for skin closure but rarely used today); 1/4-circle, used for microsurgery and ocular procedures; 3/8-, 1/2- and 5/8-circle, used for cardiovascular surgery, oral and nasal surgery; and compound curved needles. Curved needles of 3/8- or 1/2-circle are used for skin closure and gastrointestinal, genitourinary and respiratory surgeries. Compound curved needles, which have a have a straight point with a curved distal section, are used for ophthalmological procedures as well as oral, plastic and vascular surgeries, according to Chih-Chang Chu, author of “Wound Closure Biomaterials and Devices."
Cutting needles have sharp points and edges so they can penetrate tough skin easily; they typically have three cutting edges. One type called reverse cutting needle, causes less trauma to tissue and are used for ophthalmic and plastic surgery . Another type, tapercut needles, are used on tough tissue such as connective tissue. Side cutting or spatulate needles can have up to four sides and are used for ophthalmic surgery, according to Chu.
Suture is attached to most surgical needles today by bonding, a type of connection known as eyeless, or swaged. Closed-eye needles need to have suture tied through the eye, making them more bulky. French-eye needles are slitted, so that suture can be slid onto the needle.