Re: what to do.
Spondylolisthesis is when your spine has slipage due to the joints being weakend (degenerative) or in some cases, because the bone above the joint is fracutred (isthmic). There are other kinds as well other than this from what I can gather. Grade 1 is suppose to be consistant of 25% slippage. The grades go up to Grade 5, but Grade 4 seems to be 100% slippage, while Grade 5 is called spondyloptosis in which the vertebra has fallen off completely - ouch!
Your orthosurgeon is probably trying to rule out if conservative measure will relieve your pain before considering surgery. This is a normal protocol for many surgeons it seems. If nothing alivitates your pain then surgery might be considered, but you are also entitled to other opinons as well. Both Ortho and Neuro surgeons deal with issues such as this. But with it being grade 1, its just my opinion, but giving concervative measures a chance might be a good thing. From what I can find on the issue, many people can find relief, it might just depend on the therapy and the pain meds given. Good luck to you and many blessings, I hope you are able to find relief soon.