Thoracic Transforaminal Epidural Steroid Injection: Infraneural Approach

Abstract

Although thoracic epidural injections are uncommon, they are indicated for radicular symptoms with or without axial pain, resulting from thoracic spine. The transforaminal approach offers medication delivery to specific thoracic spine locations.

keywords

epidural steroid injection, fluoroscopy, Hernicated nucleus puplosis, infraneural, radiculopathy, spinal stenosis, Thoracic, transforaminal

Note: Please see pages ii , iii for a list of anatomic terms/abbreviations used throughout this book.

Although thoracic epidural injections are uncommon, they are indicated for radicular symptoms with or without axial pain, resulting from thoracic spine pathology. The transforaminal approach offers medication delivery to specific thoracic spine locations.

Several approaches can be used for a transforaminal injection. In this chapter, we will describe the infraneural approach, which has also been called the preganglionic or retrodiscal approach. With this approach, the needle will stay “low in the hole” (i.e., in the lower third of the foramen).

Using the approach described here, the needle is placed with the use of a trajectory view and advanced using multiplanar imaging, with an emphasis placed on safety. The orientation of the zygapophysial joints and the articulation with the ribs makes this injection more challenging. One must also be aware of the lung fields at all times when performing thoracic transforaminal epidural injections.

Note that the initial trajectory is quite similar to that used for thoracic discography, as described in Chapter 24 .

Trajectory View

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Confirm the level (with the anteroposterior view).
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Tilt the fluoroscope caudad or cephalad to optimize end plate visualization of the targeted segment.
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Oblique the fluoroscope ipsilaterally toward the symptomatic side, ideally with the superior articular process (SAP) bisecting the endplates.” ( Fig. 21.1 ).

Fig. 21.1

A, Fluoroscopic image of a trajectory view with the needle in position. B, Radiopaque structures, trajectory view. Target “box” is shown in red. C, Radiolucent structures (lung fields are approximated), trajectory view. Target “box” is shown in red.
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Adjust the degree of angulation for each individual intervertebral disc level.
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The needle’s initial entry is in the lower third of the foramen or “low in the hole.”
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The trajectory is similar to that used in thoracic disc access ( Chapter 24 ). There is a target “box” (shown in red) formed by the superior end plate inferiorly, the inferior end plate superiorly, the SAP medially, and the rib laterally.
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Place the needle parallel to the fluoroscopic beam.