Thumb tip amputation levels. Acceptable procedures by level are 1, split-thickness graft; 2, cross-finger flap or advancement flap; 3, advancement flap, cross-finger flap, or shorten thumb and close; 4, split-thickness skin graft; 5, shorten bone and split-thickness skin graft, advancement flap, or cross-finger flap; 6, advancement flap or cross-finger flap; and 7, advancement flap and removal of nail bed remnant. SEE TECHNIQUE 19.12.