Epidural Steroid Injection – Caudal / Interlaminar/ Transforaminal
Epidural injections contain a strong anti-inflammatory agent called corticosteroid and an anaesthetic for pain relief. This is one of the most common injections administered for pain.
An epidural steroid injection (ESI) targets the epidural space, which is the space surrounding the membrane that holds the spinal fluid around the spinal cord and nerve roots. Nerves travel through the epidural space and then branch out to other parts of your body, such as your legs. If a nerve root is compressed (pinched) in the epidural space, you can have pain that travels down your back and into your legs (commonly called sciatica, although the technical medical term is radiculopathy). An epidural steroid injection sends steroids right to the nerve root that’s inflamed.
Epidural injections are given to relieve pain in the neck, back, arm and leg due to inflammation of spinal nerves from conditions such as spinal stenosis, spondylolysis, herniated disc, degenerative disc and sciatica. They are recommended based on pain patterns and used to treat pain primarily from the spine.
Types of epidural steroid injections
Caudal epidural block
In Caudal Epidural block, the approach is through the caudal space in the low back which is entered with a Tuohy’s epidural-steroid-injection needle under fluoroscopic guidance. A radio opaque dye is given and its spread is checked under the C Arm in the epidural space and seen to line the nerve roots at the sacral and lower lumbar levels. A local anaesthetic and steroid is then injected. It is given in cases of lumbar canal stenosis with complaints of claudication pain radiating to both lower limbs.
Interlaminar epidural block
An Interlaminar Epidural block is given in cases of Ankylosing spondylitis and other indications. It is given in the lumbar region in sitting or prone position and aims to deposit the steroid in the posterior epidural space.
Transforaminal epidural steroid
In Transforaminal Epidural steroid injection, the desired nerve root is approached through the neural foramen on the affected side where the nerve root exits the spinal canal. The needle is placed near the approximate location of the nerve root in the neural foramen under fluoroscopic guidance. A radio-opaque dye is seen to line the nerve root and enter the epidural space. A local anaesthetic and steroid is then injected and washout of dye is noticed under the C Arm fluoroscope. A transforaminal epidural is commonly given in cases of Unilateral Radiculopathy due to herniated discs not only to find relief in the radicular symptoms but also to confirm the nerve root involved.
You will be taken to the pre op area where trained nursing staff will get you ready for the procedure, by taking vitals and reviewing your medications. Your blood sugar and coagulation status may also be checked if needed. Then you will enter the procedure room where you will lay, usually, face down or on a table.
The injection site is then cleaned and injection of a local numbing agent is given in the area so that you don’t feel pain during the procedure.
A thin hollow needle is then inserted into the epidural space. The doctor is guided by fluoroscopic X-ray to place the needle in the correct position. This system gives real-time X-ray images of the position of the needle in the spine on a monitor for the surgeon to view.
A contrast material is then injected through the properly placed hollow needle to confirm that the drug flows to the affected nerve when injected.
When the doctor is satisfied with the position of the needle, the anaesthetic drug and corticosteroid are injected through the same needle inserted in the spine.
You may feel some pressure during the injection but the procedure is mostly not painful. The needle is removed and the injection site is covered with a dry, sterile bandage. The procedure takes about 3-5 minutes to complete.
Risks and complications
With the use of live imaging though X-ray machines, contrast dye, and physicians trained in the latest interventional techniques, complications are rare. However, with all medical procedures, complications may occur. To help minimise risk, please follow all directions given to you by your care provider. Have all your treatment options explained, so you are aware of the risks and benefits of these procedures.
Some complications may include:
If spinal fluid leaks out of the intrathecal space, you may have a headache that gets better when you lay down. This headache usually gets better by lying flat in bed for 12 to 24 hours and drinking caffeine. However on occasion, headaches may last longer and need further evaluation.
Your pain physicians clean and sterilise your back before every procedure to prevent this from occurring. On rare occasions oral antibiotics may be needed.
This may occur if you have allergies to any medication used. Typically this is pre-treated and on occasion your physician may recommend medications for you to take after the procedure. Pay close attention to any rashes and difficulty in breathing because they may indicate the need for emergent attention.
This may occur after the procedure due to the needle puncture and can last from 3 days to a week. Usually this pain resolves and does not cause any lasting impact.
There are many side effects of corticosteroids. However, by limiting the cumulative dose of medication used, these risks are reduced. However, some symptoms you may feel include:
- Heart palpitations
- Mood changes
Epidural injections may take 2-7 days to show any effect. They may need to be repeated. As always, follow the instructions of your care provider and have your questions answered prior to the procedure.