The spinal cord branches off into 31 pairs of nerve roots. These nerve roots exit on both sides of the spine through spaces between each vertebra. Compression or inflammation of these nerves in the neck (cervical spine) or mid-back (thoracic spine) can cause symptoms including:
- Pain, which may radiate down an arm (for cervical spine) or around the chest (for thoracic spine)
- Weakness
- Numbness of the extremities
To diagnose and treat these symptoms, your doctor may use nerve root injections.
Purpose of diagnostic nerve root injections:
If your physician can’t determine the specific cause of your pain using diagnostic imaging, such as an MRI or CT scan, temporarily numbing the suspicious spinal nerve root may help to identify the source of the pain.
Purpose of therapeutic nerve root injections:
Injection of a steroid along the nerve root may be used as a treatment to help reduce irritation and swelling, thereby relieving pain. The steroid usually starts to work two days to two weeks after the injection. The pain relief varies for each individual, from no relief to long-term pain relief.
Types of nerve root injections
Selective Nerve Root Block (SNRB): This is a diagnostic-only procedure. It tests to see if a specific nerve is causing pain by blocking it with a strong anesthetic. No steroid is used. The anesthetic may cause temporary numbness, tingling, and/or mild weakness in the affected leg. These symptoms and any pain relief only last until the anesthetic wears off.
Nerve Root Injection (NRI): This is a diagnostic and therapeutic injection. Both a strong anesthetic and steroid are used and injected around the nerve and into the epidural space.
Transforaminal Epidural Steroid Injection (TFESI): This is primarily a therapeutic procedure aimed at relieving pain when the physician knows which nerve is affected. A lighter anesthetic and steroid are injected around the nerve and epidural space.
Overview of the nerve root injection procedure
Here’s what to expect during a cervical or thoracic nerve root injection procedure:
- If your pain is in your cervical spine, you will lie face up; if your pain is in your upper back, you will lie face down.
- The injection area is cleaned and numbed before the injection.
- Using fluoroscopic (X-ray) guidance, your physician will determine the appropriate path for the needle.
- Your doctor will insert a thin needle to a point immediately behind the nerve root.
- Next, your doctor will inject a small amount of contrast dye to make sure that the medication will flow exactly where intended.
- Then, your physician will inject a small amount of anesthetic, steroid, or a combination of both, depending on the procedure’s purpose.
- During the injection, you may feel a sensation of pressure in the neck or arm. This typically disappears in a few moments.
- After the procedure, you’ll spend 20 to 30 minutes in the recovery area.
Preparing for the nerve root injection
- While the procedure may take less than 15 minutes, you should allow for at least one hour at the procedure center.
- You need to arrange for a driver to be present and take you to and from the medical facility. If you do not have a driver with you, we may have to reschedule your procedure.
- For diagnostic injections, you should have some pain at the time of the procedure or be able to reproduce it consistently with certain activities or positions. If you are typically pain-free after taking pain medication, please do not take these medications for four to six hours before an injection.
- If you are taking prescription blood thinners such as Coumadin (warfarin), Ticlid (ticlopidine), or Plavix (clopidogrel bisulfate), please inform your docot. These medicines will need to be stopped before the procedure, but only after you receive permission from the doctor who is prescribing these medicines.
- If you develop a fever, night sweats, or an active infection before your procedure, your procedure will need to be rescheduled.
Possible side effects of the steroid
Side effects of steroid injections are usually minimal and go away within one to three days after the procedure. Possible side effects of the steroid include:
- Facial flushing
- Fluid retention
- Insomnia
- Low-grade fever (less than 100° F)
- For women, temporary changes to your menstrual cycle
- Headache
- For people with diabetes, temporary elevation of blood sugar levels
After the injection
- Follow the specific instructions given to you by the health care providers
- Plan to rest for the remainder of the day. You may resume light activity that is comfortable for you, but do not overexert yourself the first day.
- You may be sore from the needle placement for one to two days. If a local anesthetic was injected, you may feel a numbing sensation in your arm for a few hours until the anesthetic wears off.
- For discomfort, apply ice packs to the puncture site for 15 minutes several times a day.
- Do not soak in a tub for 24 hours after the procedure. You may take showers.
- Report any signs of infection or other unusual symptoms to your doctor, including:
- Redness and warmth at the injection site
- Increasing pain
- Swelling or drainage at the injection site
- Chills, night sweats, or fever that reaches above 100° F
- If you develop a headache:
- Stay quiet with your head and body flat
- Drink plenty of fluids
- Take Tylenol (acetaminophen) or your prescribed pain medication
- If your headache lasts more than 12 hours or is noticeably worse when you stand up, it may be an indication of a spinal leak and you should notify your doctor. This is very rare and usually gets better without treatment.
- Keep a record of your pain and symptoms after the injection and report your results as instructed by your doctor’s patient care coordinator.
Potential risks of nerve root injections
The risks of nerve root injections are minimal and are similar to any procedure involving a needle placement. These include, but are not limited to:
- Allergic reaction to the anesthetic or contrast dye.
- Infection
- Needle injury to a blood vessel, which may bleed
- Irritation of the injected area, which could cause temporary worsening pain
- Inability to place the needle at the desired target, resulting in inability to complete the injection