Lab 4 . Part 3 - Classification of sutures

Nonabsorbable suture materials

Definition: materials that maintain their tensile strength in tissue at least 60 days

• some lose strength over prolonged periods (eg. silk)
• others maintain original strength and are walled off by fibrous tissue
• can be permanently buried in tissues when necessary
  • monofilament form preferred as associated with fewer infections
  • avoid burying multifilament nonabsorbable sutures (associated with infection and draining tracts)
• should not be placed in
  • lumen of urinary bladder or biliary system as predispose to calculi formation
  • infected or contaminated sites where can form a nidus for infection

Absorbable suture materials

Definition: Materials that lose significant tensile strength within 60 days of being placed in tissue

• • arbitrary 60-day time frame refers to loss of strength NOT disappearance from the tissue. Some absorbable materials are physically present a long time but have no appreciable strength.
  • suture is broken down by phagocytosis or hydrolysis
• how rapidly a suture loses strength IS important trivia
  • has to be compared with how long the incision needs to heal and regain its strength
  • dehiscence results if use a suture that loses most of its strength before the tissues regain theirs.

Monofilament sutures

• consists of a single strand of material
• has minimal tissue drag
• decreased knot security because of smoothness so additional throws are needed to achieve secure knots
• significantly weakened by kinking or if crushed by instruments

Multifilament (braided) sutures

• consists of several fibers twisted or braided into a single strand
• generally stronger
• usually better knot security
• more tissue drag
• many available with coatings applied by manufacturer to minimize tissue drag but also decreases knot security
• should NOT be placed in infected or contaminated areas
  • bacteria can reside between individual fibers of the strand
  • isolated from immune system and antibiotics
  • results in persistence of infection as long as suture present
• can form nidus for calculi formation in bladder and biliary system if persist for significant duration

Natural suture materials

• made of natural fibers
• are absorbable or nonabsorbable types
• tend to induce more tissue reaction than synthetic materials
• common examples include surgical gut (catgut) and silk

Synthetic suture materials

• made of man-made materials
• are absorbable or nonabsorbable types
• tend to be less reactive than natural materials
• tend to lose tensile strength and be absorbed at more predictable rates
• common examples include polydioxanone (PDS) and nylon