A diagnostic injection should be done on a day in which the patient is having actual pain symptoms so that a definite determination can be made as to whether the patient’s pain has been modified or relieved by the injection. The injection is not 100% specific as there may be multiple levels contributing to the symptoms or the injection may slightly affect an adjacent level. The procedure may also be done with a therapeutic injection of steroid medication to further reduce nerve irritation.
What to Expect
Specific Blocks Types
Zygoapophyseal Joint Blocks (Facet Joints)
Medial branch blocks involve multiple injections as nerves from above and below supply the joint.
This procedure requires approximately 30 minutes per level. Patients need not be NPO (without food or water) and may drive themselves home soon after the procedure. These blocks are often combined with an injection of steroid medication into the joint for a longer, more therapeutic effect.
Orthopedic Hardware Block
A precise injection of local anesthetic can be made into the defect to determine if it is a source of pain. This is usually done with fluoroscopic or computed tomography guidance. The procedure requires no special preparation and usually takes less than 30 minutes.