These are the kinds of questions that a doctor will screen you for before a procedure. A testicular torsion is usually a medical emergency that is corrected. What was your situation and is the matter considered resolved?
Okay. Well, I'd imagine if the torsion is resolved/fixed that you'd still be able to have the vasectomy performed. There are lots of things on the internet about men that have done so. But talk to the performing doctor. Let us know what they say.