Not sure of the specifics for surgery, but for deductions in general, let's say you made $20,000 that year, and your surgery cost $10,000. You have to itemize your deductions and let's say surgery plus other deductions came to a total of $11,000. $20,000 minus $11,000 is $9,000 and you would be taxed as if you only made $9,000. Personally, I would recommend using a tax professional this year.