I have three discs that are getting thin from the aging process. One disc (the worst one) is going to be replaced with an artificial implant. Will this affect the height of the other two discs?

Probably not. Using X-rays, MRIs, and a special imaging study called fluoroscopy researchers have shown there are no changes in the height of discs directly above or below the implant.

Loosening of the implant, dislocations, or sinking into the bone can actually decrease the height of the replaced disc. Let's hope you don't run into any of those problems.