Lumbar mri showed n impingement @ l5-s1 & poss surgery'd be microdiscectomy to remove extruded part w/ min recovery. now symptoms indicate l3-l4 impingement too. how would this change poss surgery/recovery?

Include L3-4 too: Surgery could possibly be extended to include L3-4 as well as L5-S1 microdiskectomy; same surgery, just 2 levels rather than 1. Recovery would be slightly more painful, slightly longer, otherwise same plan & prognosis for recovery. Good luck!

Back surgery: You need to ask your surgeon, however if MRI was fairly recent and showed no problems at L3/L4 then answer probably no change. Pain could be from the extruded fragment migrating slightly and/or inflammation. If you were to have additional disc problems at L3/L4 then surgery somewhat lengthened but really shouldn't affect recovery much.