How are transforaminal epidural steroid injections (ESIs) administered?

Updated: Aug 06, 2018
  • Author: Boqing Chen, MD, PhD; Chief Editor: Stephen Kishner, MD, MHA  more...
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The transforaminal approach is performed by placing the needle under the pedicle in the neuroforamen, superior and ventral to the dorsal root ganglion and exiting nerve root. The needle is directed in an oblique approach towards a target point on the upper margin of an imaginary triangle (the “safe triangle”), formed by a line tangential to the lower margin of the pedicle, a line tangential to the lateral margin of the pedicle, and the hypotenuse passing obliquely inferiorly and laterally from the inferior medial corner of the pedicle. Advancement is made under lateral and anteroposterior views to provide a 3-dimensional spatial representation. (See image below.)

Transforaminal approach at the S1 level on the rig Transforaminal approach at the S1 level on the right, anteroposterior view.

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