After evaluation of your symptoms, x-rays and scans, your surgeon may decide to offer you a course of spinal injections. The aim of the injections is to reduce the pain and inflammation, which in certain types of spinal problems, can be long lasting and may obviate the need for spinal surgery.
Your surgeon will decide which of the two types of spinal injections will benefit you:
- Facet injection or facet block; or
- Transforaminal epidural steroid injection or a nerve root block
Bone scan (SPECT) showing facet arthritis
Facet joints are located behind the vertebrae and control the direction and extent of spinal movement and can occasionally become arthritic and cause pain. A facet injection involves placing medications around the painful facet joints to relieve pain and inflammation. About 60% benefit from this injection and for some, the benefits can be long lasting. Besides reducing pain, the injection can play a diagnostic role by helping to pin-point the exact region of the spine from where the pain is originating.
Transforaminal epidural steroid injection (TFES)
A disc herniation (disc prolapse) can compress the nerves coming out of the spinal cord, resulting in nerve inflammation and leg pain (sciatica). A transforaminal epidural steroid injection involves placing medications around the inflamed nerve to relieve the inflammation and pain. Some patients get immediate relief of symptoms related to the injection of the local anesthetic around the nerve root, while others have relief beginning hours or days after the procedure. Relief may last from hours to months, and in some cases indefinitely. Some patients experience no relief either because of a lack of response to the medication or because their symptoms are coming from a different source.
Bone scan showing facet arthritis
A combination of Bupivacaine (local anaesthetic agent) and Betamethasone (steroid) is used for both the injections. Bupivacaine is a local anaesthetic agent that provides early pain relief but is short acting. Betamethasone, on the other hand, reduces the inflammation in the injected area and its effect begins anywhere from 4-6 hours to one week after the injection. The steroid does not mask the pain but reduces the inflammation and swelling which cause pain.
Description of the procedure
After you lie on your tummy on a couch, the skin over the area to be injected is exposed and cleaned with an antiseptic solution (Betadine). A local anaesthetic is injected under the skin to reduce the pain that can occur when the spinal needle is inserted. The spinal needle is then inserted under x-ray guidance to ensure the accuracy of needle placement.
Potential risks and complications
The commonest side effect from injection procedures is a transient increase in pain for the first 1-3 days; this is a normal reaction to injection around an inflamed area. You may experience tenderness at the injection site and this can be reduced by applying crushed ice wrapped in a towel over the area for 15 minutes every 3-4 hours. Other possible minor and transient side effects include post- injection muscle soreness, light-headedness, fainting, headache, nausea, vomiting and an increase in blood sugar and blood pressure.
Major complications are rare and include infection, severe allergic reactions, anaphylaxis, excessive bleeding, permanent nerve damage, permanent increased pain, dural puncture, seizure, stroke and cardiovascular collapse.
Facet injection (Block)
Pars injection (Block)
If you have any concerns about the above-mentioned potential complications, discuss them with your doctor.
You should contact you doctor if you have the following symptoms after a spinal injection:
- Temperature above 38 degrees that is not improving
- Loss of bowel and bladder control or retention of urine
- Severe worsening pain
- Loss or worsening motor power (strength) in the limbs; or
- Headache in the standing or sitting position that is relieved by lying down