Delayed Primary Wound Closure Results in Increased Angiogenesis
The correct answer is A: Delayed primary wound closure results in increased angiogenesis. The fundamental principle behind delayed primary closure is that leaving the wound open initially allows for increased wound oxygenation and blood supply from developing granulation tissue, which inherently involves angiogenesis 1.
Mechanism of Delayed Primary Closure
Delayed primary closure works by potentiating local wound resistance through increased wound oxygenation and blood supply from developing granulation tissue 1. This process specifically involves:
- Enhanced angiogenesis as new blood vessels form in the granulation tissue during the 2-5 day period before closure 1, 2
- Decreased bacterial inoculum through open wound management with proper dressing 1
- Development of vascularized granulation tissue that provides better wound bed preparation 1
Why the Other Options Are Incorrect
Wound Strength (Option B)
The increased blood supply and granulation tissue formation from delayed closure would theoretically improve wound strength, not decrease it, as better vascularization supports healing 1.
Collagen Content (Option C)
Granulation tissue formation involves collagen deposition, so delayed primary closure would increase rather than decrease collagen content 1.
Scar Width (Option D)
While delayed closure may have cosmetic implications, the primary physiological effect is on angiogenesis and granulation tissue formation, not necessarily scar width 1.
Clinical Context
Delayed primary closure is performed by suturing the wound 2-5 days postoperatively after allowing granulation tissue to develop 1, 2. This technique:
- Was originally developed in war surgery for contaminated wounds 1
- Aims to reduce surgical site infections in dirty or contaminated wounds 1
- Has shown variable efficacy in modern studies, with some meta-analyses showing benefit (OR 0.65) while high-quality RCTs show no significant difference 1
Important Caveat
While delayed primary closure increases angiogenesis through granulation tissue formation, recent high-quality evidence suggests it may not provide significant clinical benefit over primary closure in terms of infection rates, and it increases costs and hospital stay 1, 2.