The muscles and joints in your neck is innervated through cervical plexus between C1 and C5 spinal dorsal root and its ganglions which have receptors that send signals about head movement and orientation to the brain and the vestibular system located in the middle and the inner ear. This system along with the larger propioceptive network in the body functions to maintain balance and muscle coordination. When this system works improperly, receptors cannot communicate with the brain and this produces dizziness and other sensory dysfunctions (1).
Cervical spondylosis ,compressive trauma and arthritis affects the intervertebral foramen which causes a disruption of blood flow by blockage of arteries in the neck; from hardening (atherosclerosis) or tearing of these arteries (dissection) to the inner ear or a lower brain region called the brain stem.
Surgery, steroid injections and whiplash trauma to the neck can also block blood flow to these important regions. Blockage of arteries in the neck from hardening (atherosclerosis) or tearing of these arteries (dissection) are causes of cervicogenic vertigo.
Intervertebral foramen is the gateway which allows for the passage of the spinal nerve root, dorsal root ganglion, the spinal artery of the segmental artery, communicating veins between the internal and external plexuses, recurrent meningeal (sinu-vertebral) nerves, and transforaminal ligaments. is where generally the anomalies occur.
No uniform agreement has been made on which classification best describes this area. Studies of the nerve root canals have clearly noted variations in the angle of take-off from the thecal sac, length of the nerve root, and placement of the dorsal root ganglion from different cervical levels.
The nerve root canal receives a dual blood supply from central and peripheral sources. The dorsal root ganglion also has a dual vascular supply that aids in preventing damage to this vital foraminal structure. The presence of ligamentous structures within the foramen has been demonstrated by a number of recent studies. These ligaments serve a protective and organizational role for the neurovascular structures of the foramen (2). Even with all the protective measures the injuries to the fragile neck area overwhelm the equilibrium between stable propioception and vertigo.
To demonstrate the variations in blood supply to the IVF area as the primary causative factor this blog cites the following study. This study was performed on cadavers to demonstrate that the infiltration of epidural steroid injections through vascular supply in and around the vicinity of the IVF may cause intrathecal disturbance showed that in two specimens, dissection was carried down to the spinal cord, demonstrating the anterior spinal, radicular, and segmental medullary arteries. Of 95 intervertebral foramina dissected, 21 had an arterial vessel proximal to the posterior aspect of the foraminal opening. Seven of these 21 were spinal branches that entered the foramen posteriorly, potentially forming radicular or segmental medullary vessels to the spinal cord. One additional ascending cervical artery formed a segmental medullary artery that joined the anterior spinal artery. This would only be injured by anterior needle misplacement. Of the seven foraminal branches, three were included in the deep dissections. Two contributed to segmental medullary arteries and one to a radicular artery. Variable anastomoses between the vertebral and cervical arteries were found (3).
The purpose of this blog is to orient my patient cohort about this type of pathological entity where surgical, local infiltrative and traction method treatments are to be performed with care and chiropractic HVLA should be prohibited due to the inherent complication of vertebral artery dissection or blockage. The Osteopathic and Naprapathic method of treatment is to be considered as treatment of choice.
Bibliography:
1) Kiara Anthony, Healthline article, medically reviewed by Kenneth Gross, M.D. Updated on September 28, 2018.
2) Gilchrist RV, Slipman CW, Bhagia SM. Anatomy of the intervertebral foramen. Pain Physician. 2002 Oct;5(4):372-8. PMID: 16886015.
3) Huntoon MA. Anatomy of the cervical intervertebral foramina: vulnerable arteries and ischemic neurologic injuries after transforaminal epidural injections. Pain. 2005 Sep; 117(1-2):104-11. PubMed PMID: 16055268.
Picture by Dr.Deepak Pal.
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