Size refers to diameter of the suture strand

  • the larger the suture diameter, the relatively stronger it is
  • measured in metric units (tenths of a millimeter) or by a numeric scale standardized by USP regulations.
  • USP scale runs from 11-0 (smallest) to #7 (largest)
    • zeros are written as 2-0 for 00 and 3-0 for 000, etc. for convenience and clarity
    • From 0 to 11-0, each extra zero corresponds to a unit decrease in diameter (e.g. 0, 00, 000, etc. until the smallest size of eleven 0s is reached)
      • ie.more zeros means smaller (and weaker)
    • #1 to #7, are referred to as “number 1” to clearly differentiate them from the metric system
  • the selected size and tensile strength should approximate the tissue being sutured. The goal is to select the smallest suture that will support the incision.
    • too fine → breaks before tissue heals resulting in dehiscence
    • too large → tissue conforms to suture rather than the opposite
    • too large → more foreign material in wound causing more tissue reaction and slower wound healing
Various Sizes of Sutures