Hi, and welcome. It is very good that you are asking these questions for your sister. I think the best place to start would be to read about myasthenia gravis on the web. I recommend the Mayo Clinic's website, because its explanations are clear and detailed but not too technical:

http://www.mayoclinic.com/health/mya...gravis/DS00375

I think the surgery you are talking about must be a thymectomy. Here is a good pamphlet that explains what the surgery is, what its risks are, and what will happen afterwards:

http://www.myasthenia.org/LinkClick....BIVoreOXJGo%3D

You say that she has muscle weakness and a positive result on the acetylcholine receptors antibody tests. That means that she has a definite diagnosis, which is excellent. However, I don't know what you mean by the episodes of absent-mindedness you describe that last one to two minutes. This is not a symptom of myasthenia gravis. Her neurologist should be looking for the cause of these episodes.

I hope this helps. Please feel free to ask any other questions.

Abby