Transforaminal epidural steroid injection
Citation, DOI and article data
Transforaminal epidural steroid injections (TFESI), also known as transforaminal nerve root injection or nerve root blocks, are performed for treatment and diagnosis of radicular pain. They differ from selective nerve root blocks (SNRB), as the aim is to get "epidural spill" and get the injectate into the epidural space. TFESI are less selective than SNRBs, which are more accurate diagnostically.
This procedure is commonly performed to manage 3:
- discogenic radicular pain
- painful central canal stenosis, typically lumbar
- failed back syndrome
- non-specific low back pain
Reviewing past imaging should aid the practitioner in technique and equipment selection. Correlating the patient's history and examination with the imaging findings is key to ensuring the correct side, level and procedure-type (e.g. epidural vs selective) is performed.
Nonparticulate steroids (e.g. dexamethasone) are usually preferred over particulate steroids (e.g. triamcinolone) in TFESI (per United States of America's Food and Drug Administration) to reduce the risk of vascular complications such as spinal cord infarction 1, however, complications have been reported with both types of steroid 2,3. Blunt-tip needles may also reduce vascular complication rates 3.
See spinal interventional procedures for further details.
Fluoroscopy and CT are the most common imaging guidance methods, and technique will depend on regional preferences, practitioner preference, equipment availability, and type of injection. However, an infraneural approach (below the nerve root) is recommended to reduce the risk of vascular complications 3.
CT can be performed in those with contrast allergies, as gas can be injected instead of iodinated contrast to confirm an epidural needle tip position ref. When contrast is injected usually a small volume (e.g. 1 mL) is needed, the pattern of contrast dispersion (e.g. focal non-linear, linear, tram-track) has not been shown to influence clinical outcomes 2.
Once a satisfactory needle tip position is obtained adjacent to the nerve root, a mixture of steroid and anesthetic can be injected.
Complications generally associated with spinal interventional procedures with TFESI-specific complications including 3:
- transient, increased pain resolving without further intervention
- spinal cord infarction, which can occur with particulate and non-particulate steroids; other mechanisms such as vasospasm or dissection proposed
Such injections are performed in order to give the patient pain relief, so then to enable them to undertake physiotherapy.
- 1. Jacob C. Mandell, Gregory J. Czuczman, Glenn C. Gaviola, Varand Ghazikhanian, Charles H. Cho. The Lumbar Neural Foramen and Transforaminal Epidural Steroid Injections: An Anatomic Review With Key Safety Considerations in Planning the Percutaneous Approach. (2017) American Journal of Roentgenology. 209 (1): W26-W35. doi:10.2214/AJR.16.17471 - Pubmed
- 2. Germann, Christoph, Graf, Dimitri N., Fritz, Benjamin, Sutter, Reto. CT-guided transforaminal epidural steroid injection for discogenic lumbar radiculopathy: influence of contrast dispersion and radiologist’s experience on clinical outcome. Skeletal Radiology. doi:10.1007/s00256-021-03881-x
- 3. Helm Ii S, Harmon PC, Noe C, Calodney AK, Abd-Elsayed A, Knezevic NN, Racz GB. Transforaminal Epidural Steroid Injections: A Systematic Review and Meta-Analysis of Efficacy and Safety. (2021) Pain physician. 24 (S1): S209-S232. Pubmed