What is a Disc Block Injection?
A disc block is an injection of a mixture of local anaesthetic and hydrocortisone (steroid) into one of the discs in your lower back. This is used when a particular disc is thought to be the cause of your pain, and you have not responded to physical therapy or are in too much pain to be able to engage in physical therapy.
How do we do it?
A disc block is carried out as a day case procedure in an operating theatre. To minimize discomfort the injection is performed under sedation, which is administered by an anaesthetist. The needle is placed under x-ray guidance, and its position confirmed by injecting a small amount of dye that shows up on the x-ray image.
What Are the Risks?
there is a risk of infection at the injection site. There is also a 0.5-1% of getting an infection in the disc. This is called discitis. If you were to get a discitis you would require a prolonged course of antibiotics, initially being administered into a vein. You may also require surgery to treat the infection. When receiving a disc block injection, you will also be given a dose of preventative antibiotics.
Sticking a needle into a disc can increase the rate of the natural degenerative processes that occur in a disc. This may mean that you experience more problems from that particular disc in the future. For this reason, we do not inject into normal discs or any disc that does not potentially look like a source of you pain on scans.
There is a very small risk of infection at the injection site, but this is rare. If you had some bleeding around the nerves following an injection there is a a very small chance that you may require an urgent operation to deal with this. To minimise bleeding we do ask that any medication that might increase your bleeding risk be stopped prior to the injection.
If you are on any medication that has the potential to thin your blood such as aspirin, clopidogrel, warfarin or any other blood thinning medication then we do need to know about this prior to the date of your injection.
Following the injection you may have some increased pain in your back. This will normally settle over a few hours.
Following the injection you may have a headache for a few hours. This should settle by the following day. There is a 1 in 1000 of the lining around your nerves being punctured when you have this type of procedure. This can result in a small leak of spinal fluid which is likely to cause a more problematic headache. If you have a persisting severe headache the day following your injection, then can you please contact the hospital to let me know so that we can manage this correctly. In this eventuality you may require a few days of bed rest or potentially a further injection into your back to put a patch over the area of leak.
Injection Site Discomfort
Following the injection you may have some localized soreness at the injection site, for which you can take some simple painkillers and it should settle over a few days.
Side Effects From The Injected Steroid
There are very few side effects when steroids are administered this way. Occasionally patients may notice some facial flushing, nausea, or mild abdominal cramps for a few days following the injection. There can also be a temporary disturbance to the menstrual cycle. Diabetics may find that the steroid alters their blood sugar control for a few days, so should monitor it closely.
An allergic reaction to injected steroid and local anaesthetic is incredibly rare. However, you must inform us of any know allergies beforehand.
What Can I Expect Following the Injection?
You will normally be able to leave hospital once you are mobile and. This is normally 2-3 hours following your injection. There may be a small dressing over the injection site that can be removed after 12 hours.
As you will have had sedation you will be unable to drive for 24 hours following the injection, and will need to arrange for someone to collect you from hospital. We would advise that you have a restful day the day after your injection, but can return to normal activities the following day. There are no other restrictions following the injection.
For the first few weeks following your injection it is important that you keep a pain diary, documenting any relief that you have had. Please can you bring this information with you when you return to the clinic. Even a temporary reduction in pain is useful diagnostic information.
If further rehabilitation is recommended, it is important that you undertake this whilst you are pain free so that you gain maximal long-term benefit. It is important that you build up any unaccustomed activity gradually.
You will be seen back in the clinic a few weeks after your injection. Your on-going treatment will be guided by your response to the injection.