Selective Nerve Root Block



This diagnostic injection into the area that surrounds is done to define the pain experienced by the patient, more precisely. Therapeutic steroid and local anesthetics are used to decrease pain and inflammation. Pain relief from the procedure can be minimal to long-term. It varies from patient to patient and it depends on the specific symptoms. Symptoms must be present for this procedure to be effective. Patients with radicular symptoms (pain in an arm or leg), which can be localized to a specific nerve root distribution, may benefit from a diagnostic and therapeutic selective nerve root injection.


  • Symptoms must be present at the time of appointment
  • Stop blood thinners 48 hours in advance; stop pain medication 8 hours in advance
  • The patient should bring previous films
  • The patient will need a driver


The patient remains awake throughout the test. Using x-ray fluoroscopy Dr. Varley uses a thin needle to place anesthetic and steroid into the nerve sheath. The patient may experience some discomfort at this time. The physician checks the needle position by means of a fluoroscope (x-ray) connected to a monitor. Contrast material, which outlines the nerve root, is placed into the nerve sheath to document the needle position and x-rays are taken. A small mixture containing a steroid and an anesthetic is injected. The immediate response to the injection is reported to help the physician with his management and treatment planning. This procedure may be repeated at 2-week intervals, up to 3 times. The goal, usually, is to avoid surgery. During the injection, the patient may feel pressure or pain. The doctor will want to know how this discomfort compares to the patient’s usual pain symptoms.

  • During the procedure, patients may feel some slight pressure or discomfort.
  • He/she may experience numbness and/or relief from symptoms for up to six hours after the injection. When the anesthetic wears off, the usual symptoms may return.
  • The area around the injection site will feel numb, warm, or asleep.
  • The steroids usually require 2-3 days to provide pain relief.
  • If there is no change in the pain symptoms after a week, an investigation into other potential pain sources may be warranted.


About 5% of patients will have side effects of steroid medications. These side effects include: facial flushing, insomnia, and occasional low-grade fever. Usually, the symptoms disappear within a couple of days.