What is a Greater Occipital Nerve Block?
A greater occipital nerve block is an injection of local anaesthetic and steroid around the nerves which supply the scalp. These nerves are located on the back of the head, and the top of the neck.
How does it work in migraine?
Most primary headaches happen because there is abnormal gain (amplification) of pain and other sensory messages in the trigeminal nucleus, in the brainstem. The greater occipital nerve feeds upwards into the trigeminal nucleus. The nerve block reduces traffic in this nerve, so the abnormal gain in the trigeminal nucleus is diminished, therefore reducing the symptoms of migraine and other primary headaches. One might guess that this treatment works for only pain at the back of the head: it can also work for pain at the front of the head, such as cluster headache.
The injection itself only takes a minute or so. The injection is 2 ml of mixed local anaesthetic and a steroid that stays at the injection site. The injection is just behind the ear so you can hear it going in. It can be done with you sitting in a chair, or lying down.
Following the injection
The back of your head may feel strange and a little numb, this is perfectly normal. Check that any bleeding has stopped before you leave the clinic; if not, press gently with a tissue on the injection site. Please ensure that you have arranged for someone to drive you home after this procedure if it is your first time; if you are familiar and comfortable with the procedure you can look after yourself.
What side effects might I get?
You will very likely notice a lump at the injection site for a few or several days. About one in 30 patients experience transient worsening of their head pain. In theory, infection of the injection site could occur. Very rarely, patients can faint with injections; these patients should be lying down to have injections.
How long will it be before I notice any benefit?
Benefit may start in a hour or so, though can take up to a week to begin; usually in the first few days.
How many do I need to have?
As many as you need, to fix your pain!
Exceptionally the injection can be repeated after a month if benefit is good but transient at that time. Otherwise, it can be repeated as often as every two months. If the injections need to be repeated every two months for a year then it may be better to consider another treatment.
Not all treatments work the same every time; if you have two successive greater occipital nerve blocks with insufficient benefit, it’s probably best to try a different treatment.
Who cannot have a nerve block?
You cannot have this nerve block if you are allergic to any of the medications being injected or if you have an active infection near the injection site.
Please make the doctor aware of any other medical problems you have now or have had in the past, before having the nerve block.
Giles Elrington MD, Medical Director & Consultant Neurologist- July 2013
This information is provided as a general guide only. If you have any queries or concerns about your headaches or medications please discuss them with your GP or the Doctor you see at the National Migraine Centre.