In order to confirm the pain generator, it is possible to precisely inject the anesthetic into or around the identified or suspected pain generator, rendering it numb or anesthetized. If the anesthetic is the type which usually lasts 24 hours, and the abnormality injected is the true cause of the pain, then the patient should experience excellent pain relief for 24 hours. Not only does such confirmation reveal potential treatment, but it also reassures the patient that the pain is not a figment of the imagination. There are general types of injections which can aid in diagnosis:
- Facet joint injection – Facet joints occur in pairs at each vertebral level and can become painful due to changes associated with aging or loss of disc height as with degenerative disc disease. A facet injection can be both a diagnostic and therapeutic tool, helping to determine the source of pain. The area is anesthetized and, with fluoroscopic guidance, a combination of local anesthetic and steroid is injected into or around the joint.
- Selective nerve root block (transforaminal injection)
- SI joint injection
- Trigger point injection is used to provide immediate relief from pain referred by trigger points. A trigger point is a tender spot in myofascial structures including especially muscles, tendons, and ligaments. It is described as feeling like a knot, tumor or band, and a painful, “twitch response” can be reproduced on compressing of the trigger point. Anesthetic, saline, steroids or Botox can be used. Trigger point injections are used when less invasive measures, such as massage or manipulation, are ineffective.