Stenosis is a general term that refers to a condition where there is narrowing in the spinal canal. This narrowing can either occur in the central spinal canal where the spinal cord resides (central stenosis) or in the holes on each side (foramen) of the spine at every level where the cervical nerves exit (foraminal stenosis).
A number of conditions can contribute to foraminal stenosis, including degenerative disc disease, facet joint arthritis, spinal stenosis, post-laminectomy syndrome, or a herniated disc/radiculopathy. When this foraminal stenosis is significant enough to cause impingement of the exiting nerve, this can cause substantial pain in the affected area.
MRI or CT imaging is used to provide accurate information about your spine anatomy. However, evidence on imaging of narrowing of the foramen does not always translate to pain. You may have evidence of multiple levels that have foraminal stenosis or may have confusing symptoms that do not correlate exactly with the distribution of the spinal nerves. In these situations, a selective nerve root block injection can be used primarily for diagnostic information to pinpoint the source of the pain.
Selective nerve root blocks are performed under live fluoroscopic guidance to ensure the accuracy and safety of the procedure. Local anesthetic can often be utilized to anesthetize individual nerves as they are exiting the spine through their respective foramen. A local anesthetic can temporarily prevent a painful nerve from sending pain signals to the brain. Steroid can be added in addition to the local anesthetic to act as a potent anti-inflammatory if the nerve is swollen or inflamed from the foraminal stenosis.
After the procedure, you will be asked whether the numbing medicine relieved your pain for the duration of the anesthetic and whether any long-term relief was acquired with the steroid..
Although extremely rare, risks may include bleeding, infection, allergic reaction to the medication, spinal headache, nerve damage, and prolonged increase in pain.