Cervical Transforaminal Epidural Steroid Injection

Abstract

Cervical transforaminal epidural steroid injections are indicated to relieve radicular symptoms with or without axial neck pain from cervical nerve root irritation. The traditional approach to the epidural space was interlaminar. Transforaminal epidural steroid injections are used to deliver the injectate to the ventral epidural space where the pain generators are located: the posterior annulus, ventral aspect of the nerve root sleeve, and intervertebral neural foramen.

Keywords

cervical foraminal canal, cervical radiculopathy, digital subtraction, epidural steroid injection, fluoroscopy

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

Cervical transforaminal epidural steroid injections are indicated to relieve radicular symptoms with or without axial neck pain from cervical nerve root irritation. The traditional approach to the epidural space was interlaminar. Transforaminal epidural steroid injections are used to deliver the injectate to the ventral epidural space where the pain generators are located: the posterior annulus, ventral aspect of the nerve root sleeve, and intervertebral neural foramen.

Neurovascular risks for this procedure are high, with known complications thought to be caused by the intravascular injection of a particulate steroid, thereby resulting in the embolism of vascular structures with infarction. Digital subtraction is strongly advised to increase sensitivity in the detection of vascular contrast flow. Note that the trajectory (oblique) view is also one of the multiplanar views. This procedure may be performed in the supine position as demonstrated in this chapter or in the lateral decubitus position.

Trajectory View ( Fig. 27.1 )

The Trajectory View (Foraminal Oblique) Is Also a Multiplanar View

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The patient is positioned supine. Rotation of the chin to the contralateral side can be used to expose the ipsilateral neck.
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Obtain a posteroanterior (PA) view.

Safety Considerations

It is imperative that the needle tip be located at the dorsal aspect of the IVF to avoid vertebral artery puncture.
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Oblique the C-arm image intensifier approximately 45 degrees toward the symptomatic side (the right side, in this case) to optimally maximize the size of the intervertebral foramen (IVF).
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The most rostral IVF is C3 (C2-C3). Count downward from the C3 (C2-C3) IVF to identify the targeted IVF.
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Tilt the C-arm image intensifier to square off the superior end plate closest to the targeted IVF.
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Adjust the obliquity and the tilt to optimally enlarge the size of the targeted IVF. Obliquity optimizes the anteroposterior width of the IVF, and cephalocaudal tilt optimizes the height of the IVF. A maximally enlarged IVF in height and width confirms that the X-ray beam has been optimally positioned parallel to the targeted root canal.
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The target point is the junction of the inferior/caudal posterior half of the IVF and the superior articular process (SAP) with skin entry over the SAP. This angle is used for needle entry and advancement.
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The needle should be advanced parallel to the C-arm beam until it contacts the SAP.
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Once the needle has contacted the SAP, needle advancement is stopped. A PA view (safety view) is obtained to determine the depth of insertion.
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Ultimately, the needle tip destination is the dorsal aspect of the IVF to avoid vertebral artery penetration.

Optimal Views in Multiplanar Imaging

After the needle is placed in the trajectory view, use the PA view to confirm that the needle tip has not been placed beyond the midline of the articular pillar (ArP).