Why would lumbar facet steroid injections work but when i did the medial branch block to see if a rhizotomy would help, it did nothing?

Facet pain: The two should be similarly effective. The question I have is whether the medicine got to the right place or if perhaps the facet injection was not contained completely within the joint and causes relief by effecting a different area or structure. I would consider repeating the injections to see if the results are reproducible. Hope this help.

Procedures: No procedure is perfect. Your scenario is quite common. Depending on the amount of anatomic alteration of the facet nerve due to joint degeneration, the medial branch nerve can be difficult to block. Therefore, the next best option is doing an intra-articular facet joint injection.

Muscle pain: Often the lumbar paraspinal musculature can also be the issue. Because the facet joint helped it suggests that the steroid actually improved pain where as the anesthetic only mbb didn't. The other question is that are their other structures that could cause pain like disc, annular tears, muscles, etc.