An epidural steroid injection (ESI) is a minimally invasive procedure that can help in relieving neck, arm, back, and leg pain caused by inflamed spinal nerves. ESI may be performed to relieve pain which is caused by spinal stenosis, spondylolysis, or disc herniation.
Medicines are delivered to the spinal nerve through the epidural space, the area between the protective covering of the spinal nerves and bony vertebrae. Pain relief may last for several days or even years. The main goal is to reduce pain so that the patient may resume normal activities and a physical therapy program.
What is an epidural steroid injection (ESI)?
A steroid injection includes both a corticosteroid (e.g., triamcinolone, methylprednisolone, dexamethasone) and an anesthetic numbing agent (e.g., lidocaine or bupivacaine). The drugs are delivered into the epidural space of the spine, which is the area between the protective covering (dura) of the spinal cord and nerves and the bony vertebrae.
Corticosteroid injections can reduce inflammation and can be effective when delivered directly into the painful area. Unfortunately, the injection does not make a herniated disc smaller it only works on the spinal nerves by flushing away the proteins that cause swelling.
The pain relief can last from days to years, allowing your spinal condition to improve with physical therapy and an exercise program.
Who is a suitable candidate?
Patients with pain in the neck, arm, low back, or leg (sciatica) may benefit from ESI. Specifically, those with the following conditions:
- Spinal stenosis: A narrowing of the spinal canal and nerve root canal can cause back and leg pain, especially when walking.
- Spondylolysis: A weakness or fracture between the upper and lower facets of a vertebra. If the vertebra slips forward (spondylolisthesis), it can compress the nerve roots causing pain.
- Herniated disc: The gel-like material within the disc can bulge or rupture through a weak area in the surrounding wall (annulus). Irritation, pain, and swelling occur when this material squeezes out and comes in contact with a spinal nerve.
- Degenerative disc: A breakdown or aging of the intervertebral disc causing a collapse of the disc space, tears in the annulus, and growth of bone spurs.
- Sciatica: Pain that course along the sciatic nerve in the buttocks and down the legs. It is usually caused by compression of the 5th lumbar or 1st sacral spinal nerve.
ESI has proven helpful for some patients in the treatment of the above painful inflammatory conditions. ESI can also help determine whether surgery might be beneficial for pain associated with a herniated disc. When symptoms interfere with rehabilitative exercises, epidurals can ease the pain enough so that patients can continue their physical therapy.
ESI should not be performed on people who have an infection or have bleeding problems. The injection may slightly elevate the blood sugar levels in patients with diabetes. It may also temporarily elevate blood pressure and eye pressure for patients with glaucoma. The patient should discuss this with the doctor.
What happens before the treatment?
The procedure is usually performed in an outpatient special procedure suite that has access to fluoroscopy. Make arrangements to have someone drive the patient to and from the office or outpatient center on the day of the injection.
What happens during the treatment?
At the time of the procedure, the patient will be asked to sign consent forms, list medications you are presently taking, and if he has any allergies to medication. The procedure may last 15-45 minutes, followed by a recovery period.
The goal is to inject the medication as close to the pain site as possible, using either transforaminal or interlaminar injection. The right type of injection depends on the patient's condition and which procedure likely produces the best results and the least discomfort or side effects.
Step 1: Prepare the patient
The patient lies on the stomach on an x-ray table. Local anesthetic is used to numb the treatment area. The patient experiences minimal discomfort throughout the procedure. The patient remains awake and aware during the procedure to provide feedback to the physician. A low dose sedative, such as Valium or Versed, is usually the only medication given for this procedure.
Step 2: Insert the needle
With the aid of a fluoroscope (a special X-ray), the doctor directs a hollow needle through the skin and between the bony vertebrae into the epidural space.
Fluoroscopy allows the doctor to watch the needle in real-time on the fluoroscope monitor, ensuring that the steroid medication is delivered as close to the inflamed nerve root as possible. Some discomfort occurs but patients typically feel more pressure than pain.
There are two ways to deliver epidural steroid injections: transforaminal or interlaminar. The best method depends on the location and source of pain.
- Transforaminal ESI (from the side). The needle is placed to the side of the vertebra in the neural foramen, just above the opening for the nerve root and outside the epidural space. Use of a contrast dye helps to confirm where the medication will flow when injected. This method treats one side at a time. It is preferred for patients who have undergone a previous spine surgery because it avoids any residual scars, bone grafts, metal rods, and screws.
- Interlaminar ESI (from the back). The needle is placed between the lamina of two vertebrae directly from the middle of the back. Also called interlaminar, this method accesses the large epidural space overlying the spinal cord. Medication is delivered to the nerve roots on both the right and left sides of the inflamed area at the same time.
Step 3: Inject the medication
When the needle is in place, the local anesthesia and steroid medication are delivered to the epidural space. The needle is then removed.