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Feb 27th
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Spinal Injections

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This overview relates to spinal injection procedures performed at Melbourne Radiology Clinic.


Types of spinal injections & procedures

Facet Joint Injections

The facet joints are sliding joints at the back of the spine which allow for mobility. Like any joint, then may become arthritic and therefore cause a sore back. Pain relief is brought about by injecting a mixture or cortisone and local anaesthetic into the facet joint (or joints if more than one is to be treated). The cortisone decreases the inflammation that is produced by the arthritis. The medication is delivered by a fine needle under CT guidance by our radiologist (medical specialist trained in this area). Some discomfort will be felt for a short time until the local anaesthetic numbs the area. The effects of the treatment vary and it is impossible to predict the duration of pain relief until the procedure is performed. In some people, pain is relieved for months, others years and still for others it produces no relief at all. In the case of the latter, your doctor may recommend an alternative treatment, which may include radiofrequency ablation.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet Facet Joint Injections

Selective Nerve Root Block (SNRB)/perineural injection

A nerve root block is used for patients who suffer from pain from a “pinched nerve”, also known as radicular pain. This may involve the arms, neck, body and legs. Radicular pain usually involves the legs where it is commonly known as sciatica. The procedure for a nerve root is similar to the information provided above for a facet joint injection except for that the needle is directed onto the nerve that is felt to be causing the pain. When gentle needle contact is made with the nerve, and if that particular nerve is the one causing you your symptoms, you will experience a brief pain that many patients describe as an “electrical, nerve-like shooting” pain. This pain will usually be in the same area of the body and/or character as the pain that you have come in to have treated. Occasionally, it may be more intense at the time of needle contact. This is common and confirms the correct position of the needle and is part of the procedure. At this point, the cortisone and local anaesthetic are injected. Just as local anaesthetic stings when it injected into the skin, so to will a stinging sensation occur in the area that the injected nerve supplies sensation to. This lasts approximately 10 seconds.

Following the procedure the body part involved may feel numb and clumsy, as the particular nerve has been anaesthetised. This is to be expected. The function and sensation of the nerve will return once the local anaesthetic wears off, usually between 20 minutes to 2 hours. Once full function has been regained and you are confident in your mobility, you are free to leave the Clinic. As for facet joint injections, the relief from this procedure is variable and usually temporary. If you require an occasional injection, such as once or twice a year, then depending on your lifestyle and preference, you may continue with repeated nerve root injections. If your pain is severe and/or the duration of pain relief obtained from the injection is short, or you feel that multiple injections are inconvenient, then you may need to consider a more permanent option, such as surgery.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Selective Nerve Root Block(SNRB) Injections

Medial Branch Block & Radiofrequency Ablation

A Medial Branch Block is a test to help your doctor understand whether pain arising from your facet joints can be relieved by numbing the nerves (“medial branches”) that provide them with their sensation. If numbing these nerves results in significant pain relief, then the test is positive. Unfortunately, as only local anaesthetic is used, the pain relief is temporary and as such, a more reliable way of relieving you of your facet joint pain (as opposed to direct facet joint injection) is to then proceed to a radiofrequency ablation. As the name implies, heat is then used to destroy these small nerves that supply the facet joints and the pain relief is usually dramatic and long lasting. The nerves may grow back, in which case the pain may return and the procedure then once again easily repeated.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Medial Branch Block


This injection is used to treat neck, back, arm and leg pain, depending on which level the needle is placed and exactly where in the spine. Once again, local anaesthetic and cortisone steroid solution is used to produce an anaesthetics and anti-inflammatory response. A CT (Computed Tomography) scanner and/or C-arm may be used to locate the right location for the needle.

The three main types of epidural treatment are:

  1. An interlaminar epidural is used to mainly treat the lower back at a specific level.
  2. A caudal epidural is used to treat back pain and sciatica and targets multiple levels at once. This procedure is therefore useful in patients who have multiple levels that contribute to their pain.
  3. A transforaminal epidural is when the injection is delivered to a specific nerve root to assist in relieving sciatica and is similar to a selective nerve root block/perineural injection.


CT guided caudal epidural injection in a patient with severe intractable back pain following spinal surgery. The needle is demonstrated within the sacral epidural space, with contrast injected to confirm position. The procedure is used in patients with multiple levels of impingement.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Epidural Injections


A discogram involves injecting x-ray dye (contrast) into the centre of a disc. The dye injected stretches the disc and the test is positive if the procedure reproduces the patient’s pain. In this way, a discogram can determine whether back pain is due to disc disruption (discogenic back pain) and also assists in identifying the correct level prior to any contemplated surgery or other procedure. Further to this, a discogram assess the type of disc disruption and whether it causes pressure on adjacent structures, especially nerves. Following discography, a CT is performed to also provide a 3-Dimensional view of the discs filled with dye. Usually multiple levels are injected in one sitting.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Discogram

Sacroiliac Joint Injections

The technique of a sacroiliac joint injection is similar to that described for the facet joints. The sacroiliac joints are at the lower part of the spine, where the sacral spine segments (the part of the spine below the lumbar spine) connects with the pelvic bones flanking the sacrum, known as the iliac bones. The joint is complex, with the lowermost level targeted for injection of cortisone. Sacroiliac joint pain is often vague and variable, such that it may be difficult to determine whether these joints are causing the patient’s pain or not. As clinical tests for sacroiliac joint pain may be unreliable, frequently a trial injection is performed to see if the pain is alleviated. Other treatment options following a response to a cortisone injection include destroying the nerves which supply the joint with radiofrequency ablation (similar to that described for the facet joints) as a more long lasting option.

For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Sacroiliac Joint Injections

Important information to tell your doctor prior to treatment

Serious side effects are rare, however if you have an existing condition, this must be discussed with your referring doctor before having treatment. People with local skin or systemic infections are at greater risk of having an infection spreading into the spine after spinal injection treatment. Therefore if you have infections including wounds, boils or rashes, please tell your doctor or arrange to have the procedure performed at a later date.
Please discuss any medical illnesses with your doctor before booking the recommended procedure.

Last Updated ( Sunday, 29 September 2013 22:47 )  
MEDICAL DISCLAIMER The Melbourne Radiology Clinic web site is not intended as a substitute for your own independent health professional's advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider within your country or place of residency with any questions you may have regarding a medical condition. Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second medical opinion.