Vince
I had the same concern when I had Kidney stones about 8 years ago.
I have been able to retain my 3rd class medical; however, as you may have noted from the previous posts, there are some things you will need to do on an ongoing basis.
Provide documentation to the FAA that you are stone free. This is usually in the form of a letter from your doctor, but could also be something as simple as a short statement on his stationary. Both have worked for me with the FAA. Since my doctor is not my AME, I just provide that information to the AME at the time of the physical and he submits it along with the rest of the medical information.
I have set up annual visits with the urologist in order to build a history and to make sure any recurrence is identified early, just in case.
In some cases, the FAA will send you a notification that they have accepted your medical and will state that you must watch your health and ground yourself in the event that you have a recurrence. I have received two of these letters in the four times I have applied for the 3rd class medical, so they are not consistent on this. Make sure you save this, since your AME will want to refer to it when you go for your next physical. Depending on the AME, they may write a letter to the FAA along with your medical submission, especially if you take medication for the stones, so they can state that the medication is not causing any side effects that could disqualify you from acting as pilot in command.
Be your own judge as to what information you provide to the FAA, but be aware that they frown on not providing your true history. I have heard that they are cracking down on folks who provide incorrect information and the fines can be hefty, on top of the fact that you will probably lose your license.
Good luck.