Lab 4 . Part 1 - Needles

• wide variety of surgical needles available
• considerations when selecting a surgical needle:
  • method of suture attachment
    • swaged generally preferred
  • shape of the needle
    • curved generally preferred
  • size
    • generally the smallest needle that will do the job is selected
  • needle point
    • taper needles are usually preferred for delicate tissues
    • reverse cutting needles are usually selected for skin and tougher tissues
  • economics and personal preference

The Basics

• most made of stainless steel
• requirements
  • sharp so penetrates tissues easily
  • strong so resists bending
  • some flexibility so resists breaking
• needle design varies according to:
  1. method of suture attachment
  2. shape and amount of curvature
  3. size of the needle
  4. design of needle point

Suture material attached to needle in 2 basic ways:

Eyed needles:

• • suture threaded through eye during surgery from inside curve toward outside
  • reusable
  • economical
  • less sharp if reused
  • less efficient (time spent threading needle)
  • more traumatic (bigger hole because double strand of suture pulled through tissue)
  • avoid threading eye twice to prevent suture pulling out as creates more tissue trauma
  • mainly used for suturing bovine skin

Swaged needles:

• • suture permanently attached to the needle
  • consistently sharp with known shape and durability (not damaged by previous use)
  • convenient as threading not required
  • more efficient as suture doesn’t pull out while suturing
  • generally preferred

• shapes vary from straight to curved

• Straight needles
  • used near surface (primarily skin)
  • inserted through tissues with fingers not needle holders
  • usually combined with hand ties
• Curved needles
  • manipulated with needle holders
  • rotating wrist in arc similar to that of needle is easiest and most efficient
  • curvature is described by amount of the circumference of a circle (e.g. 1/4, 3/8, 1/2, 5/8, etc.)
  • most common curves are 3/8 and 1/2
  • wider curves useful when suturing thick tissues or in deep or poorly accessible locations (easier to retrieve tip)
  • most commonly used

• • Needles come in various lengths and diameters
  • considerations when selecting needle size:
    1. tissue to be sutured (larger for thick dense tissue, smaller for delicate tissue)
    2. size and location of wound
    3. size of suture material needed to support incision during healing (bigger needle for larger suture)

 

• selected needle should be
  • smallest that will do the job (minimize tissue trauma)
  • large enough not to bend during insertion or extraction
  • long enough to reach both sides of incision in a single pass

• tip’s design affects its sharpness and how easily it penetrates tissue
• common needle point designs

Taper or non-cutting needles

• have a round body with a sharp pointed tip
• generally used for viscera, muscle and light fascia

• penetrates tissue, without cutting, creating a round hole
• should NOT be used for dense tissue like skin because the extra force needed to penetrate the tissue causes extra trauma or bends the needle
• taper cut tip a newer design that combines the round body with a cutting tip so can be used for both delicate and dense tissue
  

Traditional cutting needle

• triangular shaped point with 2-3 cutting edges to facilitate penetration of dense tissue
• cutting edge is on the inside of the curve (concave surface)

• • cut edge is where the tension is on the tied suture so this type of needle predisposes the suture to cutting through the tissue
  • use has generally been replaced by the reverse cutting needle

Reverse cutting needle

• cutting edge on outer surface of the curve (convex surface)
• more efficiently uses the cutting surface when curve wrist during insertion

• more resistant to suture cutting through tissue because the cut edge is opposite to the direction of tension on the tied suture
• preferred by most surgeons