Primary Wound Closure
clots form to seal the wound and provide a scaffold for cell migration. The
inflammatory phase of healing starts about 6 hours after injury. White
blood cells migrate into the wound to begin debridement. They also release
cytokines, growth factors, and other chemicals that stimulate vessel ingrowth
and tissue repair. Three to five days after injury, granulation tissue begins
to replace the fibrin plug that fills the wound. Up to this point, wound
strength is relatively poor. As collagen content increases, the wound gradu-
ally becomes stronger. The greatest rate of collagen accumulation occurs
between 7 and 14 days after injury. After 2 to 3 weeks, the wound begins
to mature as collagen content and fiber orientation change.
In clean, incised, sutured wounds, epithelium migrates across the gap
within 48 hours. Epithelium will also grow downward into the incision and
around sutures, making tracts that can give the appearance of infection. By
10 to 15 days after wounding, these epithelial ingrowths regress.
Wound healing can be affected by a variety of factors, including motion,
tension, poor blood supply, anemia, malnutrition, corticosteroids, radiation,
and antineoplastic drugs. Systemic diseases such as diabetes mellitus, hepatic
or renal dysfunction, feline leukemia, or hyperadrenocorticism will delay
healing. Healing is also prolonged when wounds are edematous or infected
or contain foreign material or necrotic debris. The use of lasers to incise the
skin will increase inflammation and risk of necrosis and decrease wound
tensile strength and cosmesis. Rate of wound healing varies with species;
for instance, incised wounds in cats gain strength more slowly than in dogs.
In general, primary wound closure is more likely to be successful when
Halsted’s principles of surgery are followed. These include gentle tissue
handling, accurate hemostasis, preservation of adequate blood supply, strict
asepsis, avoidance of tension, careful tissue approximation, and oblitera-
tion of dead space. In dogs and cats, skin wounds are often closed in two
layers. The subcutaneous tissue is closed to reduce bleeding, dead space, and
tension, and the dermis is apposed to promote rapid epithelialization.
0 comments:
Post a Comment