Contour threads are used in cosmetic/plastic surgery to vertically lift facial tissues that have dropped ("ptosed") or become sunken with age. The "ptosis" or descent of facial tissues with aging is a universal phenomenon to which much cosmetic facial surgery is directed.
Strands of 2/0 Prolene monofilament thread, with little notches cut into their sides, are placed in the subcutaneous plane under the ptosed facial skin. These are anchored under secure points in fronto-occipitalis and temporalis tissues. Dropped or "ptosed" facial skin is then elevated onto the barbed threads, and stay elevated because of the barbs. Thus the patient gets a "facelift[1] ", without any scalpel work and without any removal of skin.
In the event that a patient is unhappy with the results, the threads can be readily removed and the patient's face thence returns to its position prior to treatment.[2] Thus, Contour threads have negligible permanent "biological cost", as the effect is reversible. Effects last for a number of years, quoted as 2–5 years, after which time the positive effect is gradually lost and the patient's face returns to its state prior to treatment.