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Patient Information

CT Guided Nerve Block Injection

What is a Nerve Root Block injection?

This is an injection around the nerve root as it leaves the spine.

Why do I need to have the injection?

The injection is usually done to relieve pain and inflammation around the nerve. It is used to help leg pain (sciatica) and paraesthesia (pins and needles) and is sometimes used for back pain. The injection may also be useful to help diagnose the source of your pain. 

Who does this procedure?

The injection is usually done by a doctor in the CT injection room in the X-ray Department. They will use an X-ray machine to guide the injection.

What is injected?

  • An anti-inflammatory drug (steroid)
  • A local anaesthetic
  • A small quantity of dye is also injected so that the doctor can be sure that the injection is around the nerve.

The local anaesthetic will be responsible for any immediate relief of symptoms. When this wears off the pain may return before the benefits of the anti-inflammatory is felt. The anti-inflammatory drug may take up to 6 weeks to work. Pain may return after some time. If this occurs a decision will then be made about repeating the nerve root injection or considering other possible treatments.

Important information

Please inform the x-ray and CT staff if you:

  • Are diabetic
  • Feel unwell
  • Have an infection, cold or persistent cough
  • Have any allergies
  • Are taking any of the following medication – Antibiotics, Aspirin, Warfarin, Clopidogrel, Rivaroxaban or any other tablets used to thin the blood (some of these may need to be stopped some days before). 

Failure to do so may result in the procedure being cancelled.
As it is necessary to use X-rays during this procedure, you must inform the clinician referring you if you are pregnant or trying to get pregnant. If you find you are pregnant before the procedure, please inform the X-ray and CT staff. 

What are the risks of this procedure?

Complications are rare, but the possible risks are:

  • Temporary discomfort for a few days after your injection
  • Facial flushing for a few days
  • For females – temporary alteration of your menstrual cycle
  • Infection
  • Bleeding causing local bruising or bleeding around the nerve
  • If you are diabetic, then the injection may raise your glucose levels. These should be monitored for up to one month after the injection. If there are any changes in your diabetic symptoms, please consult your GP
  • Damage to the small veins on insertion of the needle
  • Damage to the lining around the nerve which may cause a severe headache for a few days
  • Nerve damage
  • Urinary complications (incontinence or difficulty emptying your bladder)
  • Allergic reaction to the injection which may be mild or life-threatening (anaphylaxis)

Risks from having a nerve root block are small. Please discuss any concerns with the clinician looking after you.

On the day of your procedure

  • You should arrive at the X-ray department no more than 10 minutes before your appointment time as the waiting area is limited
  • If a relative or friend brings you in, they can accompany you to the X-ray reception, where you will be booked in and handed in to the care of the team in CT. Please ensure that your relative or friend is aware that there is waiting space for patients only in X-ray
  • Relatives/friends wishing to stay on site are welcome to use the restaurant facilities in the main hospital building. Parking is available at Gates A and C. We ask for only one nominated relative/friend to contact us for updates (e.g., progress, expected discharge time). Relatives can contact X-ray reception for updates on 0121 685 4000 ext 55470
  • Take any medication as normal unless advised otherwise. Bring a list of your tablets with you.
  • You will be taken into the CT room and assessed by a nurse. This is to make sure you are fit and ready for the nerve root block injection. You will have the opportunity to ask any questions at this stage.
  • The doctor carrying out your nerve root block injection will also see you before you have the procedure.
  • You need to be prepared to be in the CT room/X-ray department for between 1.5 – 2 hours (this time may vary depending on individual circumstances_.

What the procedure involves

You may be asked to lie on either your front or back for the procedure, which usually takes 10-20 minutes. Local anaesthetic is injected into the skin and a fine needle is passed toward the nerve root under X-ray guidance. Once the needle is confirmed to be close to the nerve, the injection takes place.

What happens after your procedure?

You will be monitored by the nursing staff in the CT room and then in X-ray reception until you are ready to go home (about 30 minutes). 
Please note: You must not drive yourself home or use public transport. For your own wellbeing we advise that you are collected by a relative or friend. Hospital transport can only be booked if there is a medical need and you meet the set criteria. 

Back at home

It is important that you take things easy for the rest of the day. Do not do any excessive exercise or heavy work for the first few days. If a dressing is in place, remove the dressing the morning following your procedure. Continue to take your pain relief tablets until you notice an improvement in your symptoms. 

Follow up appointment

Need for a follow-up appointment will be discussed before you are discharged. 

Can’t make your appointment?

If for any reason you cannot make your appointment, you must let the imaging secretaries know as soon as possible on 0121 685 4000 extension 55131 from Monday to Friday 9am to 4pm. If you do not attend your appointment, you will not be added back onto the waiting list and your appointment will not be re-booked.

The Royal Orthopaedic Hospital | T: 0121 685 4000 |