Background: Spinal injections are commonly used to treat lumbar radiculitis and back pain. Delivery of medication to specific targeted pathology is considered important for a successful therapeutic outcome. A variety of routes of injection have been devised for epidural injection of corticosteroid.
Objectives: The author demonstrates a variation of the transforaminal injection technique. The radiographic spread of contrast is described using a more oblique and ventral caudad approach in the epidural space "retrodiscal." It is suggested that the radiographic findings of this technique for discogenic causes of induced radiculitis and/or back pain may yield more precise targeting of putative pathologic sources of radiculopathy and back pain in selected patients.
Methods: In patients with disc pathology and radiculitis, the anatomy of the lumbar epidural space is reviewed for its potential effect on the flow of injectate. Contrast spread was documented for lumbar transforaminal injection using a needle placement more oblique and behind the disc rather than in the cranial portion. Comparison is made to a typical contrast spread of an infra-pedicular placed transforaminal injection.
Results: Retrodiscal contrast injection results in reliable coverage of the retrodiscal region, the exiting nerve at that foraminal level and the proximal portion of the transiting segmental neural sleeve.
Conclusions: The radiographic findings demonstrate a difference between classic infra-pedicular versus retrodiscal transforaminal epidural contrast injection patterns, particularly at relatively low volumes. The clinical advantage of one technique versus the other should be established in randomized prospective studies.