RF = Radiofrequency Ablation. In my case the doc ablated the medial branch neves that go across the facet joints. And the ablation worked wonderfully!

ESI = Epidural Steroid Injection. Didn't do anything for me since my issues are more with the facets, nerve roots and not any major herniations. Even though I do have a disc bulge at L4/L5. But for whatever the reason, no pain relief from that.