Published ahead of print on September 28, 2007
doi: 10.3174/ajnr.A0707
Selective Cervical Nerve Root Blockade: Experience with a Safe and Reliable Technique Using an Anterolateral Approach for Needle Placement
K.P. Schellhasa,
S.R. Polleia,
B.A. Johnsona,
M.J. Goldena,
J.A. Eklunda and
R.S. Pobiela
a From the Center for Diagnostic Imaging, St Louis Park, Minn
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Fig 1. Patient positioning for SCNRB on the left side. A, The chin is rotated approximately 30° to the right, away from the side to be studied. To prevent sudden movements during needle placement/manipulation, we used 1 -inch paper adhesive tape. B, Note how the patient's neck is rotated and slightly extended. C, A metal clamp is used to help identify the optimal axis of fluoroscopy.
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Fig 2. Sequential fluoroscopic images demonstrate optimal needle placement (A and B) and contrast injection (C and D). A, Approximately 45° oblique projection, with slight caudal-to-cephalad orientation of the fluoroscopy axis, is centered on the lower lateral aspect of right C5–6 foramen. Needle tip (arrow) is in contact with the posterior wall of nerve root canal. B, AP image shows the needle tip (arrow) optimally positioned in the lower lateral aspect of right C5–6 neural foramen, with the needle tip contacting bone. C and D, Approximately 45° oblique (C) and AP (D) images obtained after injection of approximately 1.5 mL of contrast. The right C5 nerve root is outlined by contrast. Epidural reflux at C5 (small arrow) and C6 (larger arrow) is clearly demonstrated in D. This case represents an optimal degree of opacification for a therapeutic blockade, in which epidural reflux is desired.
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Fig 3. Optimal right C7 nerve root opacification before therapeutic injection. AP projection shows contrast surrounding the right C7 nerve root and ganglion, with epidural reflux above and below (arrows).
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Fig 4. Approximately 45° oblique (A) and AP (B) images revealing mostly peripheral opacification of the left C6 nerve root. Approximately 1.5 mL of contrast was injected before obtaining these images. Such mostly peripheral nerve root opacification is ideal for a diagnostic SCNRB.
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Fig 5. Ideal opacification of the right C8 nerve root before therapeutic injection. AP projection with caudal-to-cephalad fluoroscopy angulation of approximately 30°, intended to be parallel with the C7–T1 disk axis. Note how the needle comes from above; this approach is the only way to safely and successfully access the C8 nerve root and avoid the pulmonary apex. The nerve root is opacified proximally and distally with approximately 1 mL of contrast.
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Fig 6. Venous opacification observed during contrast injection into the lower lateral aspect of the right C6–7 nerve root canal, along the C7 nerve root. A, AP projection revealing prominent venous opacification (arrows) below the site of injection. Such venous opacification would not be visible on thin-sectioned CT, being out of the plane of data acquisition. B, After needle manipulation, repeat injection shows improved opacification of the C7 nerve sheath (curved arrows), but new venous filling above the nerve root (arrow).
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AJNR - American Journal of Neuroradiology