I had an injection in my low back that was supposed to numb one of the tiny nerves to my L5 spinal joint. I did get almost complete pain relief but it didn't last more than two weeks. Should I go back and do it again? Would the results last longer with a second treatment? It was so nice being able to walk again and go about my business pain free.
Despite our many advances in medicine and especially all the improved technology, we still don't know what causes back pain for many people. And without an understanding of the cause, it is difficult to find an effective way to treat it.
We do know now that some patients have back pain coming from the facet (spinal) joint(s). Using an injected anesthetic to the facet joint's nerve has confirmed that this area can be a pain generator. Once the nerve can no longer send signals to the spinal cord, then the pain stops. Numbing the nerve with an anesthetic agent like lidocaine is a both a diagnostic test (proves the pain is coming from that joint) and a treatment (stops the pain messages).
But the treatment isn't always successful and doesn't always last. Many patients do have a second or even third injection, which increases the chance of a successful outcome. There's another treatment that can also help some patients. And that's destroying the affected nerve with heat using radiofrequency (heat high enough to destroy the nerve tissue) Radiofrequency ablation (RFA) as it is called can relieve the pain permanently.
It's not routinely recommended because it adds to the cost of treatment and it's not always successful. Doctors don't know yet which patients will respond well to RFA, so they can't say who should definitely have this procedure. There's some evidence that people with decreased disc height or spinal stenosis (narrowing of the spinal canal or spaces for the spinal nerve roots) get results (good pain relief) with nerve blocks and radiofrequency denervation.
This is an area that remains under close examination and study. You would be best advised to go back to your physician for a follow-up evaluation and to find out what are your treatment options. A second nerve block is definitely a possibility.