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Your Nerve Block Procedure Explained
Here’s a simple overview of what happens during a nerve block for headache, explained in clear, patient-friendly terms so you know what to expect before and during the procedure.
What is a nerve block?
A nerve block for headache involves an injection of medication near a specific nerve — for example, the greater occipital nerve at the back of the head, or the supraorbital or trigeminal nerves in the forehead or face — to interrupt pain signals and reduce inflammation. It is often performed as a test block to assess how much relief you experience. If you respond well, a longer-lasting procedure such as radiofrequency ablation (RFA) of the same nerve may be considered later.
What medications we inject?
A nerve block typically involves a combination of medications. A local anaesthetic such as Bupivacaine (or occasionally Lidocaine) provides immediate numbing of the nerve for instant relief, while a steroid such as Depo-Medrol helps reduce inflammation around the nerve, aiming for longer-lasting effects over days or weeks. The procedure serves both a diagnostic purpose—to determine whether the targeted nerve is contributing to your pain—and a therapeutic purpose, by providing meaningful pain relief.
How long the relief lasts?
The local anaesthetic provides a rapid effect within minutes to hours — you may notice numbness or a significant reduction in pain soon after the injection. The steroid component usually takes a few days to show its full benefit, as it works to reduce inflammation around the nerve. The duration of relief varies between individuals: some experience benefit for days, weeks, or even months, while others may notice only modest improvement. If the block provides good relief, a longer-lasting treatment such as radiofrequency ablation (RFA) may be planned. RFA uses controlled heat to deactivate the targeted nerve, offering more sustained relief that can last for several months or, in some cases, years.
Why we do a test block first?
If the nerve block provides significant pain relief, it suggests that the targeted nerve is contributing to your headache or pain. In such cases, you may be a suitable candidate for radiofrequency ablation (RFA) or for repeat nerve blocks to maintain relief. If there is little or no improvement after the block, it indicates that the nerve is unlikely to be the main source of pain, and further assessment may be needed to identify other contributing factors.
List of possible complications & side-effects
All medical procedures and treatments carry some degree of risk. While every precaution is taken to ensure your safety, it is important to be aware of possible complications and side effects. These may vary depending on the specific treatment, your medical history, and your individual response. A non-exhaustive list includes the following:
Common Side
Effects
Temporary numbness/tingling in the area of injection (skin, scalp, forehead)
Bruising, minor bleeding at the injection site – e.g., “a little bleeding … can be stopped by gently pressing tissue or cotton wool” (occipital nerve block info) National Migraine Centre
Lump or “bruised” sensation at the injection site for a few days National Migraine Centre
Short-term worsening of headache (transient) in some cases: about 1 in 30 for occipital nerve blocks. National Migraine Centre
Rare complications
Infection at injection site (any injection)
Bleeding, especially if you take blood thinners
Allergic reaction to the medication (local anaesthetic or steroid)
Temporary weakness, tingling, numbness beyond expected local area
Very rarely nerve damage (though uncommon)
If steroid is used: there are risks (raised blood sugar, immunosuppression, etc)
For RFA later: risk of longer-lasting numbness or altered sensation in the nerve distribution area.
Nerve specifc/head region
For supraorbital/trigeminal blocks: you may have temporary numbness/weakness in the face/eyelid/forehead if the nerve affected is sensory branch. Barrow Neurological Institute
Make sure the injection is not into a blood vessel — rare but local anaesthetic systemic toxicity (LAST) is a theoretical risk.
If you have pacemaker/bleeding disorders/unstable medical condition: risk is higher; discuss with your doctor.
Additional Resources: Explore How Nerve Blocks Work
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