Facet joints (zygapophyseal joints, Z-joints) intra-articular steroid injections are performed with the goal of long-term pain relief. However, according to the evidence base medicine, these particular injections do not provide significant and long lasting pain relief compared to other modalities like radiofrequency ablation. This approach is currently used if instant pain relief required or radiofrequency ablation therapy is contraindicated.
Medial branch blocks are diagnostic injections with intent to block or numb the medial branch nerves of the dorsal rami for the facet joint to see if the zygapophyseal joint is the primary pain generator. This is a diagnostic procedure and not a treatment. The test is considered positive if patient reports 50% or more of the pain relief. The best results are usually evident when the pain relief is in 80-100% range. The pain will come back several hours or sometimes days later. This diagnostic injection is a prerequisite to performing a radiofrequency ablation. A second diagnostic injection with different anesthetic medication is required to be confident with the results of testing prior to the radiofrequency ablation therapy.
Radiofrequency ablation therapy is the therapeutic treatment phase involving the placing of Teflon-coated electrode on the region of the medial branch nerve preferably in parallel to and along the nerve in close proximity. The radiofrequency waves energy is transformed to heat energy to provide long-term pain relief by prohibiting the treated facet joints from sensing pain after coagulation its neuronal innervations. According to the evidence base medicine, this procedure provides significant pain relief for the period of 6-12 months. According to our own experience, it is very unusual if we consider repeating the treatment in less then 12 months.