When transplanting into an area with some existing hairs (be it 10%, or 50% remaining), how does the doctor decide whether to transplant between existing hairs, or ignore and simply dense pack on top of the existing hairs?
For example if a patient has 10% hairs remaining in an area, I'm guessing the surgeon densely packs directly over them as they would be quite miniaturized and weak? For the transplanted hairs that happen to intersect with these existing hair follicles, is their success rate any different? Basically, can the yield be any worse than transplanting to a completely bald scalp?
As another example, if a patient has 50% hairs remaining in an area through diffuse thinning but is stabilized on preventative medication, then I'm guessing the surgeon would transplant between hairs? What is the chance of damaging these existing hairs, or new grafts, and what exactly could cause it? What would be the expected yield (taking into account damage to existing hairs) compared to transplanting to a completely bald scalp?