Selective Nerve Root Injection (SNRI)

What is a Selective Nerve Root Injection (SNRI)?

We have 24 levels of vertebrae in our spine: 7 cervical (neck), 12 thoracic (mid-back), 5 lumbar (low back). At each vertebral level, nerves exit from the spinal cord on the right and left sides. These are called nerve roots. These nerve roots form nerves that travel throughout our arms, chest wall and legs. These nerves become painful due to irritation and inflammation at the nerve root. These nerve roots become irritated and inflamed due to stenosis (narrowing) at the opening where the nerve root exits the spinal cord. A selective nerve root injection is an injection of a steroid medication and a local anesthetic medication near the irritated nerve root. This combination of medications work to decrease the inflammation in the nerve root to relieve pain.

How and where are these injections performed?

These injections are performed in the office or in the MSC procedure room which is equipped with a fluoroscopy machine. This machine provides real-time x-ray images allowing the physician accurate placement of the needle for the injection. Your blood pressure will be taken prior to the injection. The procedure requires that you lie face-down on the injection table. Your skin will be cleansed with a betadine solution at the injection site. Please inform the staff if you are allergic to betadine. Just prior to injecting the pain medication, and through the same needle, the physician will inject a small amount of contrast dye to allow him to see the nerve root better. It is important that you notify our staff if you have an allergy to injectable contrast dye.

After the injection, band aids will be placed over the injection site(s) and you will be wheeled into the recovery area where your blood pressure will be taken and you will be provided with a snack and drink. The nurse will review your discharge instructions with you and you will be transported to your vehicle in a wheel-chair. Use extreme caution when standing/walking for the first 12 hours after the injection as you may experience numbness in your legs. You may resume normal activities the following day.

When will the injection take effect?

Pain may increase in the first day or two following the injection. If this occurs, apply ice to the injection site(s) intermittently. Please avoid the use of heat at the injection site(s). It may take 14 days for the injection to have its full effect. Please be sure to schedule a follow-up appointment with your physician 3 weeks after the injection to discuss its effectiveness.

Patient Education Sheets

For additional information about treatment, we have included this complete patient eduction sheet as a pdf to view, download and print:

View full Patient Education pdf