Cervical Interlaminar Epidural Steroid Injection—Paramedian Approach

Abstract

Cervical interlaminar epidural steroid injections are indicated for radicular pain with or without axial neck pain. The interlaminar approach is well suited for delivering medication to bilateral and/or multilevel cervical sites. C7-T1 level is typically targeted since it has the largest posterior to anterior distance between the ligmantum flavum and dura/spinal cord (SC). Also, the lower cervical levels are more likely to have an intact and fused midline ligamentum flavum. Preprocedure MRI review is helpful to examine the posterior epidural space dimensions. If the posterior epidural space is minimal to nonexistent at C7-T1, choose the T1-T2 segment.

keywords

Cervical spine, epidural steroid injection, fluoroscopy, interlaminar, radiculopathy, spinal stenosis

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

Cervical interlaminar epidural steroid injections are indicated for radicular pain with or without axial neck pain. The interlaminar approach is well suited for delivering medication to bilateral and/or multilevel cervical sites. C7-T1 level is typically targeted since it has the largest posterior to anterior distance between the ligmantum flavum and dura/spinal cord (SC). Also, the lower cervical levels are more likely to have an intact and fused midline ligamentum flavum. Preprocedure MRI review is helpful to examine the posterior epidural space dimensions. If the posterior epidural space is minimal to nonexistent at C7-T1, choose the T1-T2 segment.

After placing the needle using a trajectory view, it is advanced using multiplanar imaging, emphasizing on safety while visualizing the needle tip depth as it approaches the ventral interlaminar line (VILL) in the contralateral oblique (CLO) view and/or the spinolaminar line in the lateral view. We recommend visualizing the needle tip depth using CLO and/or lateral views rather than depending solely on the needle tip (stepping off the lamina). Typically, CLO view has better visualization than the lateral view since the shoulders frequently obstruct clear cervicothoracic region visualization in the lateral view. See Chapter 3 for more detailed CLO visualization explanation.

The epidural space is accessed by advancing the needle through the ligamentum flavum using the classic loss of resistance (LOR) technique coupled with multiplanar fluoroscopic imaging and real-time contrast visualization. The final location of the needle tip should be at the midline or slightly off the midline for more unilateral or asymmetric symptoms.

Trajectory View ( Fig. 25.1 )

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Confirm the level with the anteroposterior (AP) view.

Fig. 25.1

A, Fluoroscopic image of a trajectory view with the needle in position at the C7-T1 interlaminar space with 5 to 10 degrees of ipsilateral oblique. The needle tip is slightly to the right of the midline. B, Radiopaque structures, trajectory view. C, Radiolucent structures, trajectory view. Note that this is not the safety view for this procedure. This image is used to emphasize the location of the spinal cord (SC).
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Tilt the fluoroscope caudad.
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Maximize/optimize the targeted interlaminar space radiolucency with crisp laminar edges (usually C7-T1) using caudad or cephalad tilt.
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Oblique slightly (approximately 5–10 degrees) toward the symptomatic side (right side in this case).
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The needle is placed directly at the midline or just ipsilateral to the midline on the painful side in the target radiolucent interlaminar space.
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Because this is the trajectory view , place the needle parallel to the fluoroscopic beam .

Notes on Positioning in the Trajectory View

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Initial needle placement should be shallow in the soft tissues to avoid puncturing the dura and contacting SC.
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Interlaminar placement and further needle advancement can then be performed after rotating the C-arm into the lateral or CLO safety view. It is not necessary to “walk off” the lamina.
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There are no consistent radiolucent safety considerations in this trajectory view.

The needle should not be advanced too far ventrally in this view. We recommend observing the safety considerations demonstrated in other views (CLO and lateral) to visualize the corresponding landmarks.

Optimal Needle Position in Multiplanar Imaging

We recommend a minimum of two views, including the AP view (approaching midline) and the CLO view to confirm that the tip has not respectively crossed the VILL. Optionally, use the “true” lateral to confirm that the tip has not crossed the spinolaminar line. Advance the needle tip safely toward the target only with the use of the CLO and/or “true” lateral safety view. The AP view is used to confirm laterality or midline placement but is not a safety view.

Optimal Needle Positioning in the AP View ( Fig. 25.2 )

The needle should ideally remain close to the midline. The needle tip may be targeted slightly off the midline for the treatment of more unilateral symptoms.

There are no consistent radiolucent safety considerations in this trajectory view. To avoid dural and SC contact, the needle should not be advanced too far ventrally in this view. We recommend observing the safety considerations demonstrated in other views (CLO and/or lateral) to visualize the corresponding landmarks.