Selective Nerve Root Block
Selective nerve root blocks are injection procedures used to identify specific painful nerve roots near your spinal cord and treat pain associated with those roots. These injections differ from another, more general approach called an epidural steroid injection, which doctors also sometimes use to block nerve pain near your spinal cord.
Spinal Nerve Root Basics
Your spinal nerves emerge from various points in your spinal cord and pass through or between the bones (vertebrae) in your spinal column before continuing on to other areas in your body. The nerve roots are the portions of these nerves directly connected to your spinal cord and associated with your vertebrae. You can develop pain and a variety of changes in your normal nerve sensations if these roots become irritated and/or abnormally compressed. Potential sources of irritation or compression include a herniated spinal disc and overgrowths in your bone tissue called bone spurs.
Selective Nerve Root Block Basics
During a selective nerve root block, your doctor will target specific compressed or irritated nerves in your neck (cervical spine), upper back (thoracic spine) or lower back (lumbar spine) and inject an anesthetic, anti-inflammatory corticosteroid or a mixture of these two medications into the space immediately surrounding them. To help him find the proper nerve(s), he will use an X-ray machine called a fluoroscope, which produces live images he can view on a monitor. Some selective nerve root blocks are only used to help diagnose problems in specific nerves. Other blocks are used for the treatment of these problems. As an alternative to a fluoroscope, your doctor may use a scanning procedure called a computed tomography (CT) scan.
Selective Nerve Root Block Benefits
Compared to an epidural steroid injection—which targets a relatively large area surrounding the length of your spinal cord, called the epidural space—a selective nerve root block can provide much more detailed information to your doctor when he’s diagnosing potential sources of your back-related symptoms. Selective nerve root blocks also allow your doctor to reduce the area in your body affected by medication. However, in terms of successfully relieving your nerve-related symptoms, both epidural steroid injections and selective nerve root blocks provide more or less equal levels of benefit.
Selective Nerve Root Block Risks
Selective nerve root blocks are relatively difficult to perform, and not all facilities can accommodate their use. Potential risks associated with the procedure include temporary muscle weakness or numbness, soreness related to the injection, a temporary increase in your initial pain symptoms, allergic reactions to the corticosteroids or anesthetics contained in the injection, infection, damage to the targeted nerve or other nerves, and bleeding. Your doctor can also mistakenly place an injection in your epidural space or other neighboring areas inside your spine. If you have diabetes, a selective nerve root block can temporarily increase the glucose levels in your bloodstream. Anyone exposed to a fluoroscope can develop localized radiation burns and marginally increase their lifetime radiation-related risks.
Columbia University Medical Center – Department of Neurological Surgery: Selective Nerve Root Block (SNRB) http://www.columbianeurosurgery.org/specialties/spine/procedures/non-surgical/snrb/
International Association for the Study of Pain: Diagnostic and Prognostic Nerve Blocks (Page 298) http://www.iasp-pain.org/AM/Template.cfm?Section=Home&Template=/CM/ContentDisplay.cfm&ContentID=12201
“Techniques in Vascular and Interventional Radiology”: Epidural Steroid Injections and Selective Nerve Root Blocks http://www.ncbi.nlm.nih.gov/pubmed/19769903
St. Francis Hospital and Health Centers: Selective Nerve Root Block Injections & Transforaminal Epidural Injection http://www.stfrancishospitals.org/painclinic/NRB.pdf
U.S. Food and Drug Administration: Radiation-Emitting Products – Fluoroscopy http://www.fda.gov/radiation-emittingproducts/radiationemittingproductsandprocedures/medicalimaging/medicalx-rays/ucm115354.htm