Study Notes on Sutures

Introduction to Sutures

  • Definition of suture: Material that holds tissue together until healing is complete.
  • Historical context: Sutures have been in use since the first century AD.

Uses of Sutures

  • Opposing Edges of Lacerations: Joining the edges of a wound.
  • Obliterating Dead Space: Stitching layers of tissue to eliminate large gaps in wounds.
  • Stabilizing Joints: Example: Extra capsular repair using suture similar to fishing line for stifle joint stability.
  • Securing Bandages: Tie over bandages for large wounds.
  • Replacing Weakened Tissue: Common in hernia repairs.
  • Ligation: Tying off a vessel or ligating it with suture material.

Ideal Properties of Suture Material

  • Universally effective across different tissues.
  • Easy to handle and tie.
  • Minimal tissue reaction; does not promote bacterial growth.
  • High tensile strength yet small diameter.
  • Good knot security with fewer throws required.
  • Easy and economical to produce and sterilize.
  • Non-allergenic and avoids neoplastic changes.
  • Ability to resorb with minimal reaction after fulfilling its purpose.

Classification of Sutures

  • Absorbable vs Nonabsorbable:

    • Absorbable: Reabsorbed by body within 60 days.
    • Nonabsorbable: Enduring duration beyond 60 days without significant weakening.

  • Monofilament vs Multifilament:

    • Monofilament: Single strand; less tissue reaction; poor knot security and tends to exhibit spring-like memory.
    • Multifilament: Braided strands; greater tissue reaction; good handling and knot security; risks of capillary wicking leading to infection.

Examples of Absorbable Sutures

  • Surgical Gut (Catgut): Made from the submucosal layer of sheep intestine. High tissue reaction; causes inflammation. Not highly recommended.
    • Categories of gut: Plain, mild, medium, and extrachromic (resorption rates vary).
  • Synthetic Absorbable Suture: Developed to decrease tissue reaction.
    • Polyglycolic Acid (Dexon): Multifilament; strength decreases 33% in 7 days and 80% in 14 days.
    • Polyglactin 910 (Vicryl): Generic: polyglactin; common use, multifilament, good handling and knot security.
    • Polyglycaprone (Monocryl): Monofilament; similar properties to PDS and Maxon.
    • PDS (Polydiaxinone): Monofilament; strength retention over weeks.
    • Maxon (Polyglyconate): Monofilament; similar properties to PDS.

Examples of Nonabsorbable Sutures

  • Natural Fiber:
    • Silk: Braided, high tissue reaction, loses strength after six months.
  • Metallic Sutures: Stainless steel; minimal tissue reaction, challenging to handle.
  • Synthetic Nonabsorbable Suture:
    • Nylon (Polyamide): Can be monofilament or multifilament; has a high degree of memory.
    • Polypropylene (Prolene): Permanent suture; minimal weakening.
    • Polyester Fiber (Mersaline/Dacron): Causes capillary wicking; braided.
    • Polymerized Caprolactam (Vetifil): Braided; can harbor infections (nidus).

Suture Size and Strength

  • Suture size indicated by "ot" size; sizes vary from larger like #1 to smaller like 11 ot.
  • Contextual use: Number 2 for equine abdominal repairs, 9 ot for ophthalmic procedures.
  • Concept of size versus strength: Larger does not equate to stronger.

Suture Reaction and Tissue Interaction

  • Ranking of suture types based on tissue reaction:
    1. Surgical gut
    2. Multifilament natural fiber (silk)
    3. Synthetic multifilament (Vicryl)
    4. Synthetic monofilament (PDS)
    5. Metallic sutures (least reactive)

Sterilization and Packaging of Sutures

  • Common sterilization methods: Gamma ray radiation and ethylene oxide.
  • Prepackaged Sterilized Sutures: Recommended for use; do not resterilize due to risk of altering suture properties.

Suture Needles

  • Common Needle Points:
    • Taper: Used in delicate organs; separates rather than cuts tissue.
    • Reverse Cutting: For tougher tissue, cuts while moving through.
    • Cutting: Similar to reverse cutting but generally used interchangeably depending on preference.
  • Needle shapes: Half circles and three-eighths circles are commonly used; straight and other shapes are rare.
  • Swagged vs Eyed Needles: Swagged needles come with suture attached, while eyed needles require threading.

Additional Tools: Staplers

  • Skin staplers: use stainless steel staples, specialized removal.
  • Internal staplers (e.g., TA, GIA, EEA): enhance efficiency in surgical closures. Speed and strength are major advantages.
  • Cost of staples: Important for clinic management; proper handling and cleaning protocols are crucial.

Conclusion

  • The comprehensive understanding of sutures, their classifications, properties, and applications is essential for effective veterinary surgical practices.