Dorsal root ganglion block

What is a dorsal root ganglion block?

The dorsal root ganglion block also called as a nerve root block is an injection around one of the spinal roots as it exits your spinal cord. The nerve root can become irritated and the source of your pain due to a disc prolapse, or tightening of the small space through which this nerve transits. This injection involves depositing a steroid in this small area. 

Why is a dorsal root ganglion block done?

The main reason for doing this injection is to reduce limb pain. Steroid may have local effect on the nerve by reducing inflammation and irritation. The duration of the pain relief may vary depending on the condition this injection is being done for, may not always work, and may be only temporary in some conditions. The steroids are not licensed for this use, but they are commonly used and we have no reason to doubt that this is a safe use of these medicines (unlicensed medications are commonly used if there are no licensed medications available to treat a particular problem).

Before the injection?

If you are taking Warfarin/Clopidogrel/ Apixaban (or any other blood thinning medicine) then you will need to stop this for a short but defined period of time before the injection. The potential risks of stopping these medicines will be discussed in the clinic before the injection, and your pain doctor will give you specific instructions. 

If you take diabetic medication, then management of your diabetes around the procedure will be discussed with you in the clinic.

How is the injection performed?

This procedure is performed as a day case procedure. The risks and benefits will be discussed with you in the outpatients department and a consent form completed. You will be admitted to the day ward and seen by one of the pain doctors who will ask you if you have any further questions about the procedure, and mark the skin on your back on the correct side. Shortly before the procedure you will need to change into a hospital gown.

For this injection you will lie on your tummy on an operating table. You may have a plastic cannula (needle) placed in the back of your hand. We will monitor your breathing and circulation. You will remain awake for this procedure, very occasionally if required and considered safe, a medicine to reduce anxiety may be given to you through the drip, but you still remain conscious. Your lower back will be cleaned with a cold antiseptic solution. This injection is performed using X-rays to ensure that the needle is in the right position. Local anaesthetic is first injected into skin to numb the area. X-ray dye is used to check that the spread of the injection is satisfactory. There may be some discomfort in the back at the time of injection, and pain going down the buttock and the leg when the needle is close to the nerve.

Occasionally the injection cannot be done because the anatomy in this area can vary or be too complex to proceed safely. Alternative treatments may have to be discussed at a later date.

What happens after the injection?

Following the procedure you will be taken into the recovery room for a short period  for monitoring , then transferred back to Jefferson ward where you will need to rest for a minimum of 1 hour.

You will need to arrange for a friend or family member to collect you from the ward after your procedure as we do not recommend that you drive or travel home unaccompanied.

Immediately following the procedure you may feel a reduction of your pain. Very rarely some patients may experience leg weakness, numbness or tingling for a few hours after the injection. It may take 7 to 10 days for the steroid to begin to relieve the pain. You may resume usual activity after 24 hours. If you do experience a reduction in your pain, you should slowly build up your activity levels.

Are there any side effects?

1. The injection may cause pain at the site of injection for one or two days.
2. The injection may make your normal pain worse for a few days.
3. The steroid may affect menstrual periods in ladies for one to two cycles.
4. The steroid may also cause fluid retention for a few days.
5. Infection is a possible risk but is extremely rare.
6. You may feel facial flushing for two to three days after an epidural injection.
7. There is a small chance that the injection will make the pain permanently worse,
8. Other very rare risks include nerve damage and paralysis
9. There is a small risk of ‘vasovagal’ (temporary fainting episode) during the procedure but this can be managed by the pain doctor.