From the Research
Sacral lateral branch blocks are typically performed at the S1, S2, and S3 levels, targeting the lateral branches of the posterior primary rami of the sacral nerves as they exit the posterior sacral foramina. The procedure involves injecting local anesthetic, often with a steroid, at each level to block pain signals from the sacroiliac joint and surrounding structures. For optimal results, multiple levels are targeted in the same session since the sacroiliac joint receives innervation from several sacral segments.
Key Points
- The S1 level is accessed at the S1 foramen, while S2-S3 blocks are performed at their respective foramina along the sacrum.
- The procedure is typically performed under fluoroscopic or CT guidance to ensure accurate needle placement.
- These blocks serve both diagnostic and therapeutic purposes for patients with sacroiliac joint pain, helping to determine if the sacral lateral branches are the source of pain and potentially providing temporary pain relief.
- A study published in 2017 1 compared ultrasound- and fluoroscopy-guided sacral lateral branch blocks, and found that the ultrasound technique was associated with a shorter performance time and fewer needle passes.
- Another study published in 2022 2 assessed the technical adequacy of sacral lateral branches cooled radiofrequency neurotomy, and found that the procedure was effective in providing pain relief for patients with sacroiliac joint pain.
- The anatomy of the lateral branches of the sacral dorsal rami was studied in 2014 3, and found to be variable, with a broad range of exit points from the dorsal sacral foramina.
- A narrative review published in 2019 4 assessed the published evidence on local anesthetic blocks for the diagnosis of posterior sacroiliac joint complex pain and the efficacy of RFA of the sacral lateral branches as a treatment.
- A study published in 2009 5 found that multi-site, multi-depth sacral lateral branch blocks were physiologically effective at a rate of 70%, but did not effectively block the intra-articular portion of the SIJ.
Recommendations
- Perform sacral lateral branch blocks at the S1, S2, and S3 levels to target the lateral branches of the posterior primary rami of the sacral nerves.
- Use fluoroscopic or CT guidance to ensure accurate needle placement.
- Target multiple levels in the same session to ensure optimal results.
- Consider using ultrasound guidance to reduce performance time and needle passes.