What requirements are there to legally fly after major surgery or a medical condition? I did not fly for 6 weeks after some neck surgery and then went up with an instructor. Is this sufficient?" - Kurt
You are prohibited from acting as pilot-in-command or as a required pilot flight crew member during any medical deficiency that would be disqualifying or may interfere with the safe operation of an aircraft. FAR 61.53 and related paragraphs pertain to all medically disqualifying situations.
For example, if a pilot were to suffer a fractured arm, he or she could not fly while recovering. However, it would be perfectly acceptable for the pilot to return to flying when completely recovered and not suffering any residual functional problems.
Without knowing the details of your neck surgery my best recommendation is to consult with your Aviation Medical Examiner for specific guidance on your situation. Let the Doc make the call! There might be limiting factors that don’t readily appear to us.”