I thought it may be interesting to see a little more details on the vacuum dressing. This is a small snipping of the foam used in packing my vacuum dressing.
Basically they lay down a thin sheet of adhesive plastic, trim out of that the shape of the wound. Then they size down a larger chunk of this foam to fill the wound and cover that with the suction cup. Finally a layer of the thin adhesive plastic is again used to seal the suction cup on.
It helps the body fill in flesh under the skin as the skin is healing.