Wound Healing, Tissue Repair and Scar MCQs

Answer- A. Wound dehiscence Dehisence most often develops 7 to 10 days postoperatively but may occur anytime after surgery, from 1 to more than 20 days."- Sabiston

Explanation: Pressure sores (also known as decubitus ulcers or pressure ulcers) develop when sustained external pressure on the skin exceeds capillary perfusion pressure, resulting in ischemia and eventual tissue necrosis. The critical threshold is when pressure rises above 33 mmHg , which surpasses normal capillary pressure (≈25-32 mmHg). At this point, tissue perfusion becomes inadequate, leading to ischemic damage. Explanation of other options: Options B, C, and D (45 mmHg, 54 mmHg, 67 mmHg): Although higher pressures can cause more rapid and severe necrosis, ischemia begins once pressure exceeds 33 mmHg. Prolonged lower-level pressure, particularly over bony prominences like the sacrum and heels , can also result in ulcer formation if unrelieved.

Autograft: a graft of tissue from one point to another of the same individual's body Isograft: graft of tissue between two individuals who are genetically identical( monozygotic twins). Allograft: an organ or tissue transplanted from one individual to another. Heterotopic graft: a graft placed in a site different from that where the organ is normally located Xenograft: graft from animal to human