Your surgeon likely was referring to a total lower jaw advancement that requires before and after surgery braces. You would be fine with a sliding genioplasty which just moves the chin bone forward and not the rest of the jaw. This would still be better than a chin plant in your case as the amount of forward movement is considerable and you chin needs to be vertically shortened at the same time.
As long as your teeth fit together properly, consider a chin implant. A sliding genioplasty involves cuts in the mandible bone and plating at together in a more forward position. A sliding genioplasty is performed by an oral surgeon in a hospital setting under general anesthesia with an overnight hospital stay, since it is very invasive. A chin implant is performed under local anesthesia as an outpatient procedure which takes approximately 30 minutes. A small incision is placed underneath the chin and the implant is inserted. For more information and many chin implant before and afters, please see the link and the video below