Corset piercing starts with the creation of two rows of piercings on either side of the spine. Once these heal, they can be laced with ribbons and pulled tight. The person wearing this piercing must be very strict about keeping the area clean, which is difficult when the piercings are on your back. Risks of this kind of body modification include infection, rejection of the jewelry, and unsightly scarring. So doctors are concerned with this procedure and says it is very risky.
Also, what most people don't realize is that they should not be done permanantly. This type of piercing is reccomended to only be temporary. Wether for fun, a photo shoot, or a circus act! If not removed there is a very high risk that the rings used in the skin will indeed be rejected, which then the wounds will become irritated and can leave ugly, unwanted, scars.
I looked around at places in the area that offer this, which aren't many, and it seems the average cost for a 6 bar, 12 ring, corset piercing is around $250.00