Lumbar Zygapophysial Intraarticular Joint Injection—Posterior Approach: Fluoroscopic Guidance

Abstract

In this chapter, the approach described for zygapophysial joint injection involves the use of a trajectory view in an oblique orientation and advancement involving the use of a minimum of two views: anteroposterior and oblique. The use of a lateral view is also recommended for final confirmation, especially when the superior recess needs to be accessed. Inferior recess access will also be described.

Keywords

back pain, facet, fluoroscopy, intra-articular, joint, lumbar, lumbosacral, zygapophysial

Trajectory View

Confirm the level (with the anteroposterior view).

Oblique the fluoroscope’s image intensifier ipsilaterally ( Fig. 15A.1 ).

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If the joint is sagittally oriented, oblique angulation of the fluoroscope may not be necessary.
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Correlation with magnetic resonance images or computed tomography axial images may be helpful for estimating the optimal oblique angle at which the joint may be entered. As described by Horwitz and Smith, the zygapophysial joints (Z-joint) can have a flat or curved shape in the transverse plane and can be symmetric or asymmetric at the same level ( Fig. 15A.2A, B ).

Fig. 15A.2

Axial lumbosacral computed tomography (CT) scans demonstrating the Z-joint orientation. A, In this sagitally oriented Z-joint, the joint silhouette and posterior (dorsal) access to the joint are best visualized at 0 degrees of ipsilateral obliquity (red arrow) . As one increases the ipsilateral obliquity, the joint silhouette is less well visualized and has less optimal posterior access to the joint (green and blue arrows) . Upon further obliquity (yellow arrow), the joint silhouette is again better visualized but now correlates with the ventral–medial aspect of the joint, which cannot be accessed posteriorly. B, In this more coronally oriented Z-joint, the joint silhouette and posterior (dorsal) access to the joint are best visualized not at 0 degrees (red arrow) but at approximately 20 degrees of ipsilateral obliquity (green arrow) . Upon further obliquity, the joint silhouette is less well visualized and has less optimal posterior access to the joint (blue and yellow arrows) . Also note that at the L5-S1 Z-joint, the iliac crest prevents a more oblique approach (yellow arrow) . C, Axial CT scan of a right L5-S1 Z-joint with degenerative changes, which are mainly noted on the superior articular process. D, Axial CT scan of a right L5-S1 Z-joint with degenerative changes demonstrating the lateral border of the joint silhouette corresponding to the superior articular process. If the needle is directed toward the lateral border, the needle trajectory would less likely enter the joint space. This joint may even need a slightly contralateral oblique trajectory angle.
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The target needle destination is the middle to upper half of the joint and toward the medial border of the joint space silhouette. The superior or inferior recess can be the target too, which is discussed later in the chapter.
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Oblique ipsilaterally until the joint space silhouette can be identified, and then slightly decrease the angulation, usually 5 to 10 degrees, until the silhouette begins to fade away.
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  This optimizes access to the medial border of the joint by making use of a more medial-to-lateral entry angle.
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  As the spine ages, bony overgrowth usually occurs off the superior articular process. If the lateral border of the silhouette is targeted, it corresponds with the superior articular process, thereby resulting in a decreased probability of access ( Fig. 15A.2C, D ).

Tilt the fluoroscope cephalad or caudad, if needed.

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Little tilt is needed to optimize the entry into the joint.
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At the L5 to S1 level, the iliac crest may be superimposed over the Z-joint. Cephalad tilt may be required to optimize the trajectory view.
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In a scoliotic spine, cephalad or caudal tilt may be required to better visualize the vertebral level and the respective Z-joint of interest.

Place the needle parallel to the fluoroscopic beam.

Trajectory View Safety Considerations

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Avoid the spinal nerve by staying over the joint. Do not stray cranially above the joint.

Optimal Needle Position in Multiplanar Imaging

Optimal Needle Positioning in the Oblique View ( Fig. 15A.3 )

After the needle is placed in the trajectory view, oblique the C-arm more ipsilaterally until the joint space silhouette is clearly seen again. Advance the needle into the joint silhouette.

Safety Considerations