surgical souvenir
n.— «It turns out the collecting and, even, gifting of so-called “surgical souvenirs”—from the staples that seal a wound after surgery to gallstones to surgical screws and pins—isn’t exactly uncommon, or undercover.» —“‘For me? Gosh, honey, you shouldn’t have…’” by Stephanie Earls in Albany, New York Chicago Tribune Apr. 1, 2008. (source: Double-Tongued Dictionary)