Is there a difference between “internal sutures” and staples? Does one result in a less detectable scar?
Anything going through the skin produces a highway for bacteria to grow. Staples and sutures do just that, so bacteria can invade the body through the holes created by the needles, sutures, or threads, and through the use of stainless steel staples.
The final answers to your question relate to the opinions of doctors. I have waffled both ways in the many years of being a surgeon, and now I prefer staples over absorbable sutures. I don’t like leaving a foreign body like a suture in for very long and the absorbable suture is a foreign body. At least with staples or non-absorbable sutures, they can be removed by the surgeon when healing has occurred and wound strength builds enough to hold the wound edges together. At between 2-4 weeks, collagen production forms a lattice of ‘cable-like’ material that progressively gets laid down so that the wound will hold together. See Wikipedia for a better understanding of the various phases of wound healing. Some excellent videos covering wound healing can be found at Google Video.