Subcision is a procedure that involves surgically disrupting the fibrous tissue underneath a depressed acne scar (eg. ice pick, boxcar scars). This fibrous bundle of collagen-rich tissue can serve as an anchor that connects the bottom of the scar to the underlying tissue. It can also inhibit the regrowth of healthy tissue. In the surgical subcision of acne scars, the physician uses a needle to disrupt these fibers. This raises (elevates) the base of the scar, decreasing the depth of the pit and improving the appearance of the skin.
Subcision is often combined with the use of cosmetic fillers, such as collagen, fat or synthetic polymers to further reduce the pitted appearance of the scar.