A 30-year-old woman requires reconstruction of a large post-burn defect on the neck where adjacent skin is intact but insufficient in quantity. An inflatable silastic expander is placed subcutaneously and progressively inflated over 6 weeks. The principal biological process that allows this extra skin to be used is:

• A Biological creep: increased mitotic activity of keratinocytes generating new skin surface area ✓
• B Pure mechanical creep with permanent displacement of surrounding tissue
• C Recruitment of laxity from the retinacular cutis ligaments alone
• D Neovascular ingrowth from the underlying muscle bed

Explanation

Tissue expansion works through biological creep, meaning genuine new tissue generation with epidermal mitotic proliferation, thickening of the epidermis, and angiogenesis, not merely stretching. Mechanical creep and stress relaxation account for only a small acute component during surgery. The expanded flap retains the original vascular supply of the donor region, so neovascularisation from muscle is not the mechanism.

Reference: Grabb and Smith's Plastic Surgery, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.