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Cervical Degeneration and Cervical Vertigo

Cervical Degeneration and Cervical Vertigo

Cervical vertigo is a controversial entity in the world of balance and vestibular disorders. It has generally been a diagnosis of exclusion when a patient is feeling dizzy but has no diagnosable pathology in the inner ear or brain.

The reality is that problems in the cervical spine are commonly linked to feelings of imbalance and disequilibrium. Cervical spine problems are rarely tied to the spinning rotational vertigo of someone having inner ear pathology. Most people with cervical “vertigo” really have which can include feelings of being really off balance, shaky, or a tilt like feeling of motion.

A 2018 study looked at how a degenerative problem in the neck can be associated with a diagnosis of cervical vertigo:

Mechanoreceptors in Diseased Cervical Intervertebral Disc and Vertigo

The study looked at patients with neck and arm pain related to cervical disc problems presenting for surgery. The patients were divided into patients with and without a complaint of vertigo. The patients with vertigo were examined to rule out other causes of vertigo like vestibular neuritis, benign positional vertigo, or stroke.

The research team examined the discs from patients with vertigo, without vertigo, and a control group of cadavers with no disc degeneration. The findings were really interesting.

In patients with vertigo, there are large increases in mechanical receptors in the degenerated discs compared to the patients without vertigo, and to the control group. These Ruffini Corpuscles help detect movement and position from your joints and muscles to help tell your brain what your joint is doing in space. Free nerve fibers are responsible for transmission of stimuli usually associated with pain. You can see the distribution below:

Patients with vertigo had significantly more Ruffini Corpuscles in their degenerated discs than the non-vertigo and control group. What does this mean for dizzy patients?

 

The data from the above chart in bar graph form showing increased receptors in the vertigo patients.

As expected, the patients with neck pain only, and neck pain with vertigo have a similar increases of free nerve fibers compared to controls. That’s probably why their neck is hurting.

However, a big reason why this study is interesting is because many people in the world of rehab and manual medicine would usually associate dizziness with a decrease in mechanical receptors in their spine, not an increase.

So what gives?

We don’t know exactly what this means, but it’s possible that increased density of these receptors may be transmitting excessive or erroneous information to the brain about the joint position.

The same group did a follow up study after they had performed disc surgeries on these patients. You can see the link to the study below:

Cervical Intervertebral Disc Degeneration Contributes to Dizziness: A Clinical and Immunohistochemical Study

During the study, they performed surgery on 50+ patients and 25 patients refused the surgery and received basic physical therapy and cervical collar recommendations. You can see the results below:

 

Comparison of patients with cervical dizziness and neck pain getting surgery vs routine physical therapy and neck bracing.

So Is Surgery the Right Answer for Cervical Dizziness?

Maybe for some cases. If you have radiating arm pain with weakness tied to a badly herniated disc, then surgery might be able to help resolve both complaints, but there’s still a lot of research that needs to be done. Surgery is a BIG deal, and generally reserve that for really bad herniation cases with clear signs of neurological deficit like weakness, loss of reflexes, and atrophy of muscle.

The good news is there are a lot of ways to address cervical dizziness beyond routine physical therapy, and they have really great outcomes. One method is by improving the curve in the neck. A randomized trial of curve based rehab compared to routine physical therapy showed significant improvements in neck pain and dizziness at 1 year.

You can read some more about cervical curves and dizziness at this link:

Working on your curves: Long term outcomes from fixing military necks

A randomized clinical trial of cervical curve rehab on cervical dizziness

There’s also numerous cases of cervical dizziness that have no signs of degeneration in their spine. This is especially prevalent in patients with dizziness after whiplash and head injury in young athletes. These patients seem to do well when we focus on the upper neck where the injury is likely to affect the ligaments of the craniocervical junction.

Comparison of mulligan sustained natural apophyseal glides and maitland mobilizations for treatment of cervicogenic dizziness: a randomized controlled trial.

Long story short, degeneration of the cervical spine doesn’t have to be a sentencing for dizziness. It’s a risk factor, but it can be modified with the application of effective conservative interventions for the neck.

Dizziness and the Cervical Spine: Beyond Cervicogenic Dizziness

Read Time: [6 minutes]

Outline:

The cervical spine has been a known source of dizziness since the 1950’s with a classification as cervical vertigo. While the true spinning sensation of vertigo is not common with cervical spine issues, a feeling of imbalance, disorientation, light headedness, swaying, and unsteadiness have all been linked to problems in the cervical spine, especially the craniocervical junction.

Cervicogenic vertigo has a contentious history as a legitimate clinical entity. This stems from the fact that cervicogenic vertigo has no distinct biomarker and remains a diagnosis of exclusion; a leftover diagnosis when a more obvious inner ear cause doesn’t exist.

Cervicogenic vertigo may or may not exist as it’s own unique clinical entity, but there’s little doubt that the cervical spine plays a key role in balance and equilibrium. In this article, we’ll talk about how a dysfunctional cervical spine can be causing dizziness, and how cervical spine interventions can be a useful therapeutic option for people with dizziness disorders of many types.

The Anatomy of Cervicogenic Dizziness

While the diagnosis of cervicogenic vertigo has been contentious, the anatomical connections linking the cervical spine to symptoms of dizziness are not.

Neck Muscles, Ligaments, and Joint Receptors

The neck is loaded with receptors that help the brain know where the head is in relation to the body. These receptors come from the small suboccipital muscles, the cervical discs, the cervical joints, and the cervical ligaments. The receptors from the suboccipital muscles in particular have an unusual amount of density when compared to the rest of the spine [Source]. When you move your neck, these receptors help to control how fast and how far you move your neck. They are also receptors that are very active even if your head isn’t moving because we spend most of our time with our head up fighting gravity. All of these signals are transmitted to the brain which has to make constant decisions about where to put the head next.

Image result for upper cervical spine ligaments and muscles

When you have an injury like a whiplash or head trauma, the muscles and ligaments of the neck are susceptible to injury, and that injury takes away one of the methods that your brain uses to keep track of the head. If your brain can’t tell where your head is in space, then dizziness and a sense of imbalance is the result.

Cerebellum and Vestibular Nuclei

The cerebellum and vestibular nuclei are 2 really important parts of the brain that play a role in dizziness and balance problems originating from the neck.

The vestibular nuclei is the routing center for the signals traveling from your inner ear through the vestibular nerve. The primary job of the vestibular nuclei is to take the information coming from your ears and to calculate where the head is in space and to move the eyes appropriately in response to these signals. While the bulk of the input into the vestibular nuclei is coming from the ears, the vestibular nucleus also receives afferents from the cerebral cortex, visual centers, spinal cord, and cerebellum. It takes in all of this information and calculates where the head is in space based on what you see (visual), head direction (inner ear), and proprioception (muscle and joint activity).

Image result for cerebellum and vestibular nuclei

The cerebellum is generally thought of as a subdivision of the brain that aids in coordination of muscle movements. However, the cerebellum has an large chunks of real estate devoted to eye movements and modulation of the vestibulo-ocular response. The cerebellum also plays a role in how the vestibular system impacts the spinal muscles via the vestibulospinal tract.

These regions of the brain are important because the same muscles, ligaments, and joint receptors we discussed earlier have direct and indirect connections to the vesibular nuclei and the cerebellum.

The Vertebral Artery

The vertebral artery passes through the transverse foramina in the cervical spine. At the level of C1 and C2, the vertebral artery takes on a more tortuous path into the skull to supply the brain stem and cerebellum with oxygen. Most clinicians think of the vertebral artery as a potential source for arterial dissection that can cause stroke. However, there are documented cases of transient vertebrobasilar insufficiency caused by rotation of the neck. This syndrome has been named Bow-Hunter Syndrome or rotational vertebral artery vertigo (RVAO). [Source]

Studies have shown that decreases in blood flow from the vertebral artery can cause transient ischemia through the vertebral artery when the neck is turned in rotation. It’s not known whether the ischemia is affecting the brain stem/cerebellum, or if the ischemia is hitting the labyrinthe itself because of the way the artery branches out toward the peripheral vestibular apparatus.

Beyond Cervicogenic Dizziness

Therapies for the cervical spine can make an impact on cervicogenic dizziness. These therapies can commonly include cervical exercises, osteopathic manipulation, upper cervical chiropractic approaches, and other manual therapy techniques. The use of these modalities has largely been associated in patients who have reported dizziness following a trauma to the neck such as whiplash disorder [Source].

Is there a role to play for cervical spine-based therapies for other causes of dizziness and imbalance?

While there’s limited evidence to pull from, there are numerous anecdotes and case reports of patients with motion sickness, Meniere’s-like illness, and vestibular migraine showing improved outcomes while receiving care focused on addressing cervical spine dysfunction.

Let me be clear, I have no supporting research to support what I’m going to say next. These are just observations from 8 years of working with dizzy patients.

Many patients with feelings of dizziness but do not have full peripheral vestibular loss likely have problems of central processing of sensory information. Plastic changes in the central nervous system that can promote a sense of dizziness can include:

  • Inapporpriate Sensory re-weighting for balance
  • Inappropriate afferentation into the vestibular nuclei and cerebellum
  • Anxiety related to pathologies or activities that promote dizziness
  • Decreased cellular activity in key sensory areas of the brain due to disrupted hemo/hydrodynamics

Simplified flowchart showing the way sensory information contributes to balance

By understanding some of the interconnected nature of the senses that produce a feeling of balance, we can leverage treatments to create neuroplastic changes in the central nervous system that may help a person adapt when vestibular function is compromised.

When it comes to dizziness, there are so many anatomical players and varying degrees of compromise, we can’t rely on one thing to fix all types of dizziness. By using the cervical spine to help stimulate the proprioceptive system, we might be able to help some patients compensate with a deficit where they weren’t able to before. We may also be removing one extra stressor to the balance system that was preventing the body from compensating appropriately.