Can a employer use my prescription medication and emergency surgery on my yearly review?

As a general matter, you cannot be discriminated against or harassed in employment due to a disability, or serious medical condition. If you feell you are, you could file an employment discrimination complaint with the federal EEOC.
There are limitations, though--the protection you get against discrimination or harassment is not absolute. In particular:
1) You have to be able to do your job, at least with "reasonable accommodation," or changes to procedure or provision of assistive devices which is not too expensive or too disruptive to the employer. If you can't do the core or critial elements of your job, then you may be terminated (or demoted, transferred against your will, pay or hours cut, etc.). So to use a common example: say you are a warehouse employee who *must* be able to life up to 50lbs to the job. If you are injured or have surgery and are restricted to lifting no more than 10lbs, they could terminate you.
2) You can only miss work for health conditions or medical care (including surgery) if a) you had and used paid time off (PTO) which you had earned for the absence, and/or b) were eligible for (and your employer covered by) FMLA leave and used it. Otherwise, if you missed work without using PTO or FMLA leave, you had an unauthorized absence, and your employer may take actions against it.
3) If your prescription medication impairs you at work in a way that posses a danger or liability or damage risk to yourself, others, or the employer's property, the employer may terminate you if you stay on that medication: they do not have to accept those risks.