PMC7445511_01
The cross-sectional anatomy and the needle trajectory of ultrasound-guided intradiscal injection using C6/7 level as an illustration.. Abbreviations: AS, anterior scalene; C7R, C7 root; CA, carotid artery; Eso, esophagus; LCo, longus colli; Omo, omohyoid; SCM, sternocleidomastoid muscle; ST, superior trunk of brachial plexus; Tra, trachea; Thy, thyroid.
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Therefore, the needle entry point was determined with the trajectory just passing the lateral edge of the internal jugular vein (IJV) to have enough angle to avoid the uncovertebral joint and enter the disc (Figure 1).
Short- (A) and long-axis (B) ultrasound imagings of the cervical spine showing the in-plane and out-of-plane injection of the C5/6 intervertebral disc respectively. Dual-split display is used with B-mode on the left side and power Doppler mode on the right side. Arrowheads, needle shaft; void arrowhead, needle tip.. Abbreviations: AS, anterior scalene; CA, carotid artery; Eso, esophagus; IJV, internal jugular vein; LCa, longus capitis; LCo, longus colli; Omo, omohyoid; SCM, sternocleidomastoid muscle; STA, superior thyroid artery; VA, vertebral artery.
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After the needle had reached the annulus fibrosus (Figure 2A), the transducer was rotated to the long axis of the neck to check the needle tip position out-of-plane and perform fine adjustment to enter the disc (Figure 2B).
The anteroposterior fluoroscopy view validating the needle placement and contrast spread during the injection of C5/6 intervertebral disc.
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Further validation could be achieved by injecting the contrast and visualizing the spread of the contrast under fluoroscopy (Figure 3).