Wound Healing and Suture Knowledge

1. Wound Healing and Suture Knowledge ASR Certification Prep Kim Bayer, SRS, BS, CVT, LATg

2. Tissue Handling / Technique Goal isto minimize trauma • Gentle • use minimal tension with tissue • Retractors should be placed to avoid excessive tension • Proper use of instruments • DO NOT CRUSH • Use Proper Technique • Keep Tissue Moist • Dry tissue is dead tissue • Minimize Time

3. Incisions • Heal side-to-side, not end-to-end • There is little advantage to making an incision too small to easily view the surgical site

4. Tissue Handling / Technique • Different surgical techniques induce different levels of damage • cutting with sharp instrument • minimal traumatic • cuts / divides the cells • little adjacent cell damage • cutting with scissors • causes crush and tear trauma • relatively traumatic • adjacent cell damage

5. Tissue Handling / Technique • blunt dissection between / along tissue planes • minimal trauma

6. Tissue Handling / Technique • clamping tissue with hemostats / etc. • causes crushing of the cells • very traumatic • causes release of vasoconstrictors, clotting factors • proper for clamping vessels for ligation / hemostasis

7. Tissue Handling / Technique provide gentle retraction with proper instruments

8. Tissue Handling / Technique • Keep Tissue Moist “The solution to pollution is dilution” • Irrigate, rinse the incision surgery site • Lavage, irrigate body cavities

9. Hemostasis • Bleeding should be stopped whenever possible • Excessive bleeding may cause hematomas or increase dead space • Hematomas prevent wound apposition and retard healing • Blood is a natural food for micro-organisms and a large clot will help protect them from the body’s immune system • Bacteria inside the clot will be protected • Bleeding may be slowed or stopped by applying pressure, clamping, electro/thermocautery, and with various chemicals • Excessive pressure may lead to tissue necrosis

10. Dead Space and a Clean Wound • Remove all non-essential material • Wounds with excessive debris should be thoroughly lavaged with an appropriate sterile fluid (isotonic saline, LRS, Tis-U-Sol, etc.) to flush them away • Dead Space is an open area in closed tissue • Filled with room air, it prevents tissue apposition, provides a space for blood and other fluid influx, and may harbor micro-organisms

11. Dead Space

12. Classification of Wounds • Clean • Standard surgical wound • Clean-contaminated • Clean wounds that are contaminated by entry into a viscus resulting in minimal spillage of contents • Contaminated • Lacerations, fractures, gross spillage from the GI tract, resulting from a break in aseptic technique • Within 6 hours of initial colonization a wound can be infected

13. Classification of Wounds • Dirty-infected • Caused by perforated viscera, abscesses, or a prior clinical infection • Ongoing infection at time of surgery may lead to a 400% increase in infection rates

14. Problems • Infection • The source of infection should always be determined • Before closure of an infected wound the wound should be drained, debrided, and a small opening or drain left in • Dehiscence • Wound reopens • May result from too much tension on tissue, improper suturing technique, or improper suture materials

15. Wound Healing • Skin and fascia are the strongest but regain tensile strength quite slowly • Stomach and small intestine are weak, but heal quickly

16. Physiology of Wound Healing Phases of Wound Healing • Inflammatory Phase • Migration /Proliferation Phase • Maturation Phase Healed Incision Inflammatory Migration /Proliferation Maturation

17. Physiology of • Wound Healing • Inflammatory Phase • 0 - 5 Day • can be prolonged • inflammatory and “clean-up” process • plasma, cells, fibrin, blood components • neutrophils, monocytes • remove debris • “remove the trash” • epithelialization / migration (as early as 48 hours) • clinically characterized by swelling, redness, warmth • strength due to suture Incision Inflammatory

18. Physiology • Inflammatory Response • Clinical Signs • swelling • redness • warmth / heat • Course / Duration • peak within 24 hours, • subsiding by day 3 • Inflammation results in pain / discomfort

19. Wound Healing-Phases • Phase 1 • Inflammatory response causes an outpouring of tissue fluids, accumulation of cells and fibroblasts, and increased blood supply • Leukocytes produce enzymes to dissolve and remove damaged tissue debris

20. Wound Healing-Phases • Phase 1 (day 1 to 5) • Inflammatory response phase • Fluids flow into the wound and a scab forms • Localized edema, pain, fever, and erythema present • Basal cells migrate over the incision from the skin to cover the wound • Closure material is the primary source of tensile strength

21. Wound Healing-Phases • Phase 2 • Fibroblasts begin forming collagen fibers in the wound • Beginning of the return of tensile strength

22. Wound Healing-Phases • Phase 2 (day 5 to 14) • Fibroblasts migrate toward the wound site • Begin forming collagen fibers • Tensile strength rapidly increases • Lymphatics recanalize • Blood vessels bud • Granulation tissue forms • Capillaries develop

23. Physiology • Maturation Phase • begins ~ day 14 and continues for months • collagen fibers become oriented along the “stress” line of the incision and form crosslinks • increases tensile strength • contraction Healed Incision Maturation

24. Wound Healing-Phases • Phase 3 • Sufficient collagen is now laid down to withstand normal stress

25. Wound Healing-Phases • Phase 3 (day 14 until done) • Tensile strength continues to improve for as long as one year • Skin regains 70 to 90% of its original strength • Collagen content remains constant but cross-links with other fibers • Scar is formed which grows paler as new vessel construction tapers off • Wound contraction occurs over a period of weeks or months

26. Wound Healing Types • First Intention • Wound edges brought together during closure at the time of surgery • Second Intention • Wound is left open and heals from the bottom up • Slower than first intention and creates more granulation and scar tissue • Third Intention • Wound is initially not closed and remains open until a granulation bed formed, then the granulated tissue is closed using standard techniques • Useful in infected wounds • Infected tissue should not be closed or it will dehiss • Infection is resolved naturally, or with topical and systemic treatments

27. Closure / Suturing • Proper Apposition • Restore alignment of the tissues • close / decrease dead space • balance adequate closure with too much suture • suture is a foreign body and too much can effect healing

28. Closure / Suturing • Proper Suture • use minimal size suture that has sufficient strength • knot security • absorbable vs. non-absorbable

29. Sutures • Ideal suture material • All-purpose, composed of material which could be used in any surgical procedure (the only variables being size and tensile strength) • Sterile • Nonelectrolytic, noncapillary, nonallergenic, and noncarcinogenic • Nonferromagnetic, as is the case with stainless steel sutures • Easy to handle

30. Sutures • Ideal suture material • Minimally reactive in tissue and not predisposed to bacterial growth • Capable of holding securely when knotted without fraying or cutting • Resistant to shrinking in tissues • Absorbed with minimal tissue reaction after serving its purpose • Doesn’t exist!

31. Sutures • Surgeon should select suture materials for • High uniform tensile strength (quality) • Permitting use of finer sizes • Suture should be the smallest diameter that will do the job • Consistent uniform diameter • Sterile • Pliable for ease of handling and knot security • Freedom from irritating substances or impurities for optimum tissue acceptance • Predictable performance

32. Sutures • Size • Generally stated in “oughts”; i.e., 3-0, 5-0, etc. • 2-0 is larger than 4-0, 0 is larger than 2-0, etc. • Some suture and wire is larger than 0, then numbered 1 and higher • 2 is larger than 1, 6 is larger than 1, etc. • From smallest to largest: • 7-0, 3-0, 0, 1, 3, 7, etc.

33. Sutures Monofilament Monofilament is a single strand • Passes through tissue easily, won’t harbor micro-organisms • Ties easily • May be weakened by crushing (clamping in forceps or needle holders) • Has more “memory” • Continues to hold the shape as it lay in the package • Good for percutaneous sutures • Knots may slip over time due to the slipperiness of the suture

34. Sutures Multifilament Multifilament is a bundle of strands, like rope • Affords greater tensile strength, pliability, flexibility, and knot security • May harbor micro-organisms and “wick” them down the suture • Should not be used for percutaneous sutures

35. Sutures Absorbable Absorbable suture holds temporarily but gradually loses tensile strength and is eventually mostly or completely absorbed

36. Absorbable Sutures Surgical Catgut: Plain or Chromic Absorbed by proleolytic enzymatic digestive process. Polyglactin 910 : Vicryl® Polyglycolic acid: Dexon® Poliglecaprone 25: Monocryl® Polydixanone: PDSII® Polyglyconate: Maxon® Absorbed by Hydrolysis

37. Sutures Nonabsorbable Nonabsorbable suture will retain tensile strength and not be absorbed • Many nonabsorbable sutures (silk) will lose some tensile strength over time • Useful for device fixation, areas of extreme tension, slow healing areas, or percutaneous skin sutures • Selected for procedures where the suture should be permanent

38. Non-Absorbable Sutures Monofilament Polypropylene: Polyester Fiber: Mersilene®, Dacron®, Ethibond®, Ti.cron® Monofilament Nylon: Ethilon®, Dermalon® Braided Nylon: Nurolon®, Surgilon® Silk Surgical Stainless Steel Wire

39. Conventional Cutting Needle needle body is triangular and has a sharpened cutting edge on the inside Primarily used for skin closure.

40. Reverse Cutting Needle cutting edge on outer curve For tough, difficult-to-penetrate tissues

41. Taper Point Needle needle body is round and tapers smoothly to a point Used for soft, easily penetrated tissues

42. Blunt Point Needle Taper body For blunt dissection and suturing friable tissue

43. Spatula Needle flat on top and bottom with a cutting edge along the front to one side Primarily used for eye surgery

44. Surgeon’s Knot • Extra throws do not add appreciable strength to the knot and may, in fact, weaken it while adding extra bulk • An initial double throw followed by one or two single throws is more than sufficient • The exception is nylon monofilament sutures, where two successive double throws are useful to prevent slippage

45. Suture Patterns • Simple Interrupted • Maintains strength and tissue position if one portion fails • Requires more time and suture material • Has minimal holding power against stress

46. Suture Patterns • Horizontal Mattress • Tension suture • Useful in skin of dog, cow, and horse • Rapid and involves less suture material • Difficult to apply without excessive eversion • Should pass just below the dermis

47. Suture Patterns • Horizontal Mattress • Tightness should be such that the skin edges just meet

48. Suture Patterns • Vertical Mattress • Tension suture • Stronger than the horizontal mattress • Time consuming and requires more suture material

49. Suture Patterns • Cross-mattress • Tension suture • Brings tissue into good apposition • Useful in suturing stumps (amputations) • Also useful for rib apposition and abdominal muscle closure

50. Suture Patterns • Gambee or Crushing • Useful in intestinal anastamoses • Permits minimal leakage • May reduce fluid passage through the lumen underneath • Crushing is similar to a vertical mattress pattern