For example will Medicare cover cosmetic surgery?
Sorry, but most likely no - Medicaid pays only for diagnosed conditions, none of which those address. The surgery must address a diagnosed condition or illness and your claim that you will be psychologically damaged would need to be corroborated by an independent psychologist. And even then, I would hazard a guess Medcaid would deny the claim without a ton of supporting tests and possibly a second opinion.
How about Chiropractors? Only for subluxation of the spine.
https://questions.medicare.gov/app/answers/detail/a_id/303/~/does-medicare-cover-chiropractic-services%3F
How often can men get a PSA examination or digital examination under Medicare? Once a year.
http://www.medicare.gov/navigation/manage-your-health/preventive-services/prostate-cancer-screening.aspx?AspxAutoDetectCookieSupport=1
How often can women get a mammogram? Once a year for women over 40!
http://www.eldercareteam.com/public/648.cfm
These are some rationing actions by Medicare that I know about.
Please note that there will always be rationing of health care because the wealthy can afford more health care than the rest of us. And the very wealthy can even self insure.
To preserve some basic coverage in Medicare, more rationing will be necessary which I view as being far preferable to doing away with it by converting to a voucher program. About 15 years ago, we discussed what we might give up in Medicare to preserve it. The unanimous opinion was to put a cap on expensive operations such as organ transplants and perhaps solid body parts (spine, hips, knees).
* http://en.wikipedia.org/wiki/Death_panel
** http://www.nytimes.com/2010/12/26/us/politics/26death.html