Is the derma roller similar to a microdermabrasion? the concept behind a derma roller sounds similar to microdermabrasion. are they the same?

No very different: Microdermabrasion completely removes the to player of your skin (poor analogy = mowing your lawn) an may be greater superficial irregularities. Dermaroller is creates superficial puncture wounds (poor analogy = aerating your lawn) which produces small wounds that promote collagen formation.

Dermaroller: Is a cylindrical device with microneedles that pucture the skin. The idea is to stimulate those tiny wounds (which usually do not leave a mark) to heal, causing collagen formation and tightening. Some doctors feel that dermarolling can also transfer living melanocytes to areas that do not contain them, potentially improving skin pigmentation issues. Microdermabrasion removes top dead layers only.