Doctors apparently often don't reveal a finding if they think it's not likely to be a problem for the patient. Why worry the patient needlessly?

At least I'm guessing that that is the way the thinking goes. I appreciate it when I'm told if there's a finding, and a number of times doctors have mentioned something like "a blood blister in your ear" or something else that I hadn't been aware of.

Tarlov cysts are apparently asymptomatic as a rule. That's probably why the surgeon didn't mention it:

Tarlov cysts: A cause of low back pain? - Mayo Clinic

I hope you can get back to your bowling soon! I used to bowl and it was very enjoyable (even though I was terrible at it). I can understand that you would miss it. Interesting chitchat among the players, nice atmosphere, whenever I was bowling anywhere, but maybe truly competitive bowling isn't so relaxed.