Diagnostic and Therapeutic Selective (Transforaminal) Epidural Spinal Injection

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What is the epidural space and why may a selective epidural spinal injection be helpful?

The covering over the nerves in the spine is called the dura. The sleeve-like space surrounding the dura is called the epidural space. Nerves travel through the epidural space and out of the spine through small nerve €œpassageways before traveling into your arms, chest or legs. Inflammation of these nerves from a damaged disc or from contact with a bone spur, may cause pain in your arms, chest or legs.
Cross section of the spine showing the spinal cord and the epidural space with a catheter in itA cross-sectional illustration of the side of the spine shows the spinal canal and cord, epidural space, and placement of a catheter. Placement of the catheter is guided by fluoroscopy; a type of real-time x-ray.A selective epidural injection places anti-inflammatory medicine (cortisone) around a spinal nerve and may help reduce inflammation, which can cause or contribute to pain. By stopping or limiting nerve inflammation, the epidural injection may help promote healing€.

Although not always helpful, epidural injections reduce pain and improve function in most people within 3-7 days. They may provide permanent relief or provide a period of pain relief that will allow other treatments like physical therapy to be more effective.

A selective epidural injection also provides diagnostic information. If the nerve injected becomes numb after the procedure, and that nerve is the reason for your pain, you will feel immediately better. This helps to prove that the nerve we injected is the source of your pain. This helps in guiding future treatment options including any future surgical interventions.

One or more injections?

Performing a repeat injection depends on your response to the prior injection. If you obtain excellent relief from an epidural, you do not need to have it repeated. If you have partial sustained benefit (>35% relief) the epidural can be repeated for possible additive benefit. If an epidural injection provides minimal benefit (<35 % relief), the physician may choose another injection be performed with a change in technique and/or cortisone used.

What will happen to me during the procedure?

  1. An IV (intravenous line) is started and medication to help you relax is administered.
  2. The skin area is cleansed using an antiseptic.
  3. Using a temporary local medicine by injection, the physician numbs the skin area where the needle will be inserted.
  4. Using fluoroscopy (real time x-ray) guidance, the physician inserts and positions the needle.
  5. To confirm the needle is properly positioned, a small amount of contrast is injected. As the contrast is injected, the doctor can see how the pain relieving medicine spreads into and around the epidural space.
  6. Once confirmed, the physician injects the anti-inflammatory and pain relieving medication (eg, corticosteroid).
  7. The injection site is covered with a small bandage or dressing.

What should I expect after the procedure?

You may or may not obtain improvement in the first few hours after the injection.

  • Report your remaining pain (if any) and record the relief you experience over the next week in a €œpain diary (usually provided by your physician). 
  • Take your regular medicines after the procedure, but try to limit your pain medicines the first 4-6 hours after the procedure so that the diagnostic information obtained from the procedure is accurate.
  • You may notice an increase in your pain lasting for several days. This occurs after the numbing medicine wears off but before the cortisone has a chance to work. Ice will typically be more helpful than heat during this time.
  • You may begin to notice an improvement in your pain 1-5 days after the injection. Improvements will generally occur within 10 days after the injection.

On the day of the injection, you should not drive and should avoid any strenuous activities. On the day after the procedure, you may return to your regular activities. When your pain has improved, start your regular exercise/activities in moderation. Even if you are significantly improved, gradually increase your activities over 1-2 weeks to avoid recurrence or your pain.

SpineUniverse Editorial Comment: Dr. Dreyfuss has provided excellent information for patients who undergo this procedure. Instructions and information provided by your physician may vary.

Commentary by Gerard Malanga, MD

Epidural Injections can be a very helpful adjunct in rehabilitation of patient's the spine pain that radiates into an arm or leg or in the thoracic spine around the chest or trunk. They work by placing cortisone (a potent anti-inflammatory medication) close to an inflamed nerve. This allows the patient to be fully able to regain full motion and increase the muscular support of the spine critical in the recovery and prevention of future episodes. They are generally not indicated in spine pain that does NOT radiate from an irritated spinal nerve.

Most patients actually respond to just 1-2 injections; therefore, they should not be routinely performed in a "series of three". In my experience, 60% of patients require only one injection and only 10-20% will require 3 injections. Certainly, if there is little or no pain relief after trying 2 injections, it is unlikely that the third injection will be of benefit. In addition, most patients can be treated with a local anesthetic without the need for sedation which requires an IV and a longer recovery immediately after the procedure.

Commentary by Leonardo Kapural, MD, PhD

Epidural glucocorticoid injections are commonly given to relieve pain and improve mobility without surgery, buying time for healing to occur or as an attempt to avoid surgery after other conservative approaches failed. Those injections have a good theoretical rationale, but they do not help every patient. Who then should receive an epidural glucocorticoid injection and how many? For leg pain greater than the back pain, guidelines from a respected source (Abram S, Anesthesiology, 1999:91:1937-1942) suggest that patients who had full pain relief from the first epidural injection should not receive another one but to be re-evaluated in 4 weeks and followed thereafter.

Those patients who still have some residual pain after the first injection should receive a second and third injection, and patients who did not get any benefit from the first injection should not receive another one. Patient selection is very important in deciding on the type of injections patients should receive. Transforaminal injections (different approach to the epidural space) may produce longer pain relief and may also predict whether a patient might benefit from surgery or not (for details, see review McLain et al, The Spine Journal, 2005). For patients with the diagnosis of lumbar canal stenosis, improvement after such injections may be longer lasting than it was initially thought (Kapural et al, 2005).

Commentary by Todd J Albert, MD

The difference between a selective nerve block and an epidural steroid injection is the specificity. A selective nerve block can be used if a specific nerve is suspected as the primary cause of the pain. We prefer this type of injection because of its enhanced diagnostic/ therapeutic qualities, and the fact that the needle is not placed directly into the canal housing the spinal cord.

Commentary by Steven Richeimer, MD

Epidural injections can be done at any level of the spine: cervical (neck), thoracic (mid-back), lumbar (low back), and sacral (tailbone area). The thoracic epidural may be a valuable tool in the treatment of mid-back and chest wall pains. These problems might be caused by disc problems, arthritis of the spine, or even shingles.

Updated on: 02/07/19
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Gerard Malanga, MD
New Jersey Sports Medicine, LLC
New Jersey Regenerative Institute
Leonardo Kapural, MD, PhD
Pain Physician
Carolinas Pain Institute
Todd J. Albert, MD
Surgeon in Chief and Medical Director
Korein-Wilson Professor of Orthopaedic Surgery
Weill Cornell Medical College
Steven Richeimer, MD
Chief, Division of Pain Medicine
Keck School of Medicine
University of Southern California
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