Injections
Injections in the back or neck are generally done for two reason. One is to the aid the diagnosis and help the surgeon plan treatment. The second is the help the patients symptoms. All injections are straightforward, day case procedures. In some circumstances they are done in theatre with some sedation, in others, in the radiology suite with the patient awake. In all injections types most patient experience a two stage response. The first is due to the local anaesthetic and generally last 24 hours. The second stage starts between 2 and 6 weeks and is from the anti-inflammatory effects of the steroid.
Caudal Epidural
Caudal epidural are the swiss army knife of lumbar spine injections. They can be useful for treating a number of problems such a back pain coming from the discs and facet joints, as well as inflammation around nerves causing leg pains. They are non-specific, meaning they do not target any specific nerves and thus are rarely used as a diagnostic injection. They are different from the epidural injection commonly used in childbirth in a number of ways. Firstly they are a single injection done at the very bottom of the spine (caudal). Antenatal epidurals are done in the middle of the lumbar spine and are often a continuous infusion with a tiny plastic tube placed around the nerves. Secondly the injection, like all other spinal injections, is a mixture of steroid and local anaesthetic. The local anaesthetic is much weaker than the type used in the antenatal epidural so you should not experience the same numbness and weakness. Finally, with a caudal epidural, the position of the injection is confirmed using an x-ray machine and small amount of dye or contrast. This shows up on x-ray and shows exactly where the injection will flow.
Foraminal Epidural
This is a lumbar epidural, similar to the caudal epidural. This time the injection is placed directly around specific nerves. This makes it more selective and can thus be used as a diagnostic tool. It is very useful when two nerves are being pinched from a bony spur or disc bulge.
Selective Nerve Root Block
Finally, it is possible to pick off individual nerves in both the cervical and the lumbar spine. Generally very selective injections are used to try and delineate where pain is coming from. The same medication mixture of steroid and local anaesthetic is used. As the injection starts to work, we generally regard it as a very good surrogate for what an operation would do.
