I'm not on medication and my fingers tingle occasionally and I put this down to diabetes, along with odd sensations in my feet and a burned feeling on the tip of my tongue (NOT due to drinking my coffee too hot). But I also have bad circulation in my hands which I may have got from my dear old mum, who was very thin and perpetually cold.
If you can find out anything useful from your surgery that's great, but to be honest I just make up my own diagnosis as I go along while I'm feeling generally ok.