Neck movement during cervical transforaminal epidural injections and the position of the vertebral artery: an anatomical study

BACKGROUND: Cervical transforaminal epidural steroid injections (CTFESIs) are sometimes performed in patients with cervical radiculopathy secondary to nerve-root compression. Neck movements for patient positioning may include rotation, flexion, and extension. As physicians performing such procedures do not move the neck for fear of injuring the vertebral artery, we performed fluoroscopy and cadaveric dissection to analyze any movement of the vertebral artery during head movement and its relation to the foramina in the setting of CTFESI. PURPOSE: To determine cervical rotational positioning for optimized vertebral artery location in the setting of cervical transforaminal epidural steroid injections. MATERIAL AND METHODS: Four sides from two Caucasian whole cadavers (all fresh-frozen) were used. Using a guide wire and digital subtraction fluoroscopy, we evaluated the vertebral artery mimicking a CTFESI, then we removed the transverse processes and evaluated the vertebral artery by direct observation. RESULTS: After performing such maneuvers, no displacement of the vertebral artery was seen throughout its course from the C6 to the C2 intervertebral foramina. To our knowledge, this is the first anatomical observation of its kind that evaluates the position of the vertebral artery inside the foramina during movement of the neck. CONCLUSION: Special caution should be given to the medial border of the intervertebral foramina when adjusting the target site and needle penetration for the injection. This is especially true for C6-C4 levels, whereas for the remaining upper vertebrae, the attention should be focused on the anterior aspect of the foramen. Since our study was centered on the vertebral artery, we do not discard the need for contrast injection and real-time digital subtraction fluoroscopy while performing the transforaminal epidural injection in order to prevent other vascular injuries.