Selective spinal and joint injections are being performed with increasing frequency in the management of acute and chronic disorders of the musculoskeletal system. Effective treatment of chronic spine and joint pain requires accurate identification of the correct pain source. Interventional pain specialists play a critical role in the selective provision of spinal injection techniques to diagnose and treat musculoskeletal pain disorders.
One of the most common pain disorders seen by interventional pain specialists is spine and sacroiliac joint (SIJ) pain. The facet (zygapophyseal) joints can be significant source of spinal and extremity pain. These joints, and the nerves innervating them, can produce cervical, thoracic, lumbar, and referred pain (head, shoulder, scapula, buttock, thigh, and leg). The SIJ, which also is innervated, has been shown to be a significant source of referred pain in the buttocks, hip, and posterior thigh.
The injections can be directed at specific target sites in and around the spine. Because of the precise needle localization needed and the technical difficulty of performing these procedures, the use of fluoroscopy and contrast dye are essential. Epidural injections frequently are performed without radiographic guidance, but incorrect needle placement into subcutaneous, intraligamentous, and intravenous locations occurs in up to 25% of cases. Therefore, fluoroscopic visualization with an epidurogram, perisheathogram, or arthrogram is highly recommended, especially in postoperative cases in which anatomical boundaries are disrupted and imaging studies are difficult to interpret accurately.
Sometimes diagnostically reproducing the pain trigger during these procedures facilitates accurate identification of the painful structure. Typically, non-affected nerve roots will not trigger a severe pain response when they are mechanically irritated by a spinal needle or contrast dye. In addition, when combined with a local anesthetic or corticosteroid solution, spinal injections can provide temporary pain relief—which would indicate a therapeutic benefit and a positive response to the procedure.