Selective Nerve Root Block
A lumbar transforaminal epidural steroid injection or selective nerve root block is a type of epidural steroid injection for treating low back and leg pain.
What is the epidural space?
The dura is a protective covering of the spinal cord and its nerves. The space surrounding the dura is called the epidural space. In the lower back it is called the lumbar epidural space.
What causes the pain in the epidural space?
The lumbar area of the spine has five bones, called vertebrae. Soft discs located between these vertebrae cushion them, hold them together, and control motion. If a disc tears, chemicals inside may leak out. This can cause inflammation of nerve roots or the dura, and cause pain. Bone spurs, called osteophytes, can also press against nerve roots and cause pain.
How do I know if I have disc and nerve root pain?
If you have pain in your low back when you bend your back, you may have lumbar disc and dural inflammation. If pain travels to your leg when you bend your back, you may have nerve root inflammation. Common tests such as MRIs can show disc bulges and nerve root compression, but may not show a torn and leaking disc. A lumbar epidural injection can determine if a disc problem, dural, or nerve root inflammation is what is causing your particular pain.
What is a selective nerve root block?
In a lumbar epidural injection, an anesthetic and a steroid are injected into the epidural space to reduce inflammation. If the needle is positioned next to an individual nerve root, it is called a selective nerve root block or transforaminal epidural steroid injection. This technique puts medication directly along an inflamed nerve root.
What happens before treatment?
The doctor who will perform the injection will review your medical records and imaging studies to plan for the best location for these injections. Patients who are taking aspirin or blood thinners may need to stop taking the several days before your epidural steroid injection, doctor will provide specific instructions. Discuss any medications with your doctors, including the one who prescribed them and the doctor who will perform the injection. The injection is usually performed in an outpatient procedures suite that has access to fluoroscopy. You will need make arrangements to have someone drive you to and from the office or outpatient center the day of the injection.
What happens during treatment?
Before your injection, you will be asked to sign consent forms, list medications you are taking, and list any allergies to medications. Procedure may last 15-30 minutes followed by a recovery period. Patients remain awake for these procedures. Sedatives can be given to help lessen anxiety. The patient will be lying face down on the table, will receive a local anesthetic, which will numb the skin before the injection is given. If IV sedation is used, your blood pressure, heart rate and breathing will be monitored during the procedure. With the aid of a fluoroscope (a special X-ray), the doctor will direct a hollow needle through the skin and muscles of your back into the individual opening where specific nerve root(s) come out. Fluoroscopy allows the doctor to watch the needle in real-time on the fluoroscope monitor to make sure that the needle goes into correct location. Contrast agent is injected into the epidural space to confirm correct needle position and desired medication spread along the targeted nerve roots. Some discomfort may occur, but patients typically feel more pressure than pain. After the needles are confirmed to be in correct position, the doctor will inject mixture of local anesthetic and corticosteroid medication next to inflammed nerve root(s). The needle is then removed.
What happens after treatment?
Most patients can walk immediately after the procedure. After being monitored for a short time, you can usually leave the office or suite. Someone must drive you home. Typically patients will resume full activity the next day. If soreness around the injection site is present the following day, it may be relieved by using ice and taking mild pain medications such as Tylenol. The doctor’s office may want to follow up with you 7 to 14 days after the procedure to assess you response to this injection. You may be provided a diary to record you response to this procedure. You may notice a slight increase in pain after the numbing medicine wears off and before the corticosteroid medication starts to take effect. If discs are the source of pain, you may begin to notice pain improvement in two to five days after the injection. If after three injections you experience no or a little pain relief, then it is unlikely that you will benefit from more injections. Additional diagnostic tests may be needed to accurately diagnose your pain.
What are the risks?
The potential risks associated with inserting the needle include bleeding, infection, allergic reaction, headache, and nerve damage (rare), corticosteroid medication induced side effects such as weight gain, water retention, flushing (hot flashes), mood swings or insomnia, and elevated blood sugar levels in diabetics. These usually resolve within 3 days. Patients who are being treated for chronic conditions (e.g. heart disease, diabetes, rheumatoid arthritis, or those who cannot temporarily discontinue anti-clotting medication) should consult their personal physician for a risk assessment. With few risks, epidural steriod injections are considered an appropriate nonsurgical treatment for some patients.
How long can I expect pain relief?
The length of time that you can expect pain relief depends on the amount of inflammation you have. Sometimes an injection can bring several months of pain relief, and then further treatment is needed. Other times, a single injection can bring long-term pain relief. If your pain is caused by injury to more than one area, only some of your symptoms will be helped by a single injection.