What are the lateral branch nerves and why are lateral branch blocks helpful?

Lateral branch nerves are the very small nerves that allow one to feel pain from part of the sacroiliac joint.

These nerves do not control any muscles or sensation in your legs. They are located along the back of the sacrum.

We have strong evidence to suspect that your sacroiliac joint is the source of your pain.


Therefore, you may benefit from having the small lateral branch nerves and their pain signals interrupted via a controlled nonsurgical heat lesion produced by a special needle.

Before interrupting these nerves and their pain signals we first block the lateral branch nerve signals, usually on two occasions, with numbing medicine as a test. This tells us whether or not you are likely to benefit from having the lateral branch nerves interrupted at a later date by the special radio-frequency (RF) needle. This more permanent treatment is called RF lateral branch neurotomy.

What will happen to me during the procedure?



Next, the physician will use x-ray guidance to direct a very small needle over the lateral branch nerves.

He/she will then inject several drops of contrast dye to confirm that the medication will only go over these lateral branch nerves.


What should I do and expect after the procedure?



You may or may not feel improvement in the first few hours after the injection depending upon if the lateral branch nerves that were injected are carrying pain signals from your sacroiliac joint to your brain.

On occasion, your buttock may feel numb or odd for a few hours after the injection.


Although the main purpose of this procedure is as a test to see whether you would benefit from a subsequent lateral branch neurotomy, on occasion long term relief can occur from injecting medication over these nerves.




If your pain level is less than 4 out of 10 (with 10 being the worst pain imaginable), please call our office. It may be necessary to reschedule when the pain is stronger so the test is more accurate.

Call us: 425.899.4930
