Ross Hauser, MD
Our research team has published its findings on the relationship between cervical spine instability and Hypermobile Ehlers–Danlos syndrome (hEDS). To our knowledge, systematic evaluation of cervical spine instability and adjacent neurovascular findings in patients with hEDS has not been studied making these novel research findings or first of its kind.
Published in the Journal of Clinical Medicine we show evidence that cervical spine pathology, internal jugular vein compression, and vagus nerve degeneration are uniformly prevalent in hEDS patients. This can explain how cervical spine instability may contribute to, or be the basis for, the multisystem involvement (the myriad of symptoms) in a subset group of patients with Hypermobile Ehlers–Danlos syndrome (hEDS).
Read full Article | Download PDF | Back to Research
Below is a summary of findings and observations.
Paper summary
Although cervical spine and neurovascular issues are important in hypermobile Ehlers-Danlos syndrome (hEDS), current understanding remains limited and provides challenges in the treatment of the patient. The challenges stem from the current research that has primarily focused on complications involving the upper cervical spine in individuals with hEDS. While the current studies highlight problems associated with the upper cervical region, there has been little investigation into the underlying mechanisms of symptoms and the clinical significance of the many symptoms that may be related to cervical spine instability.
Our findings
This study was conducted to analyze objective test results in patients diagnosed with hypermobile Ehlers-Danlos syndrome (hEDS) who were seen at the Hauser Neck Center in Ft. Myers, Florida. The primary goal was to demonstrate the presence of cervical spine instability and neurovascular complications within this patient population. By identifying these issues, we aimed to contribute to improvements in treatment strategies for individuals with hEDS.
Patient Data
Eligible participants were those with hEDS, ranging in age from 20 to 50 years, who visited our neck center between January 1, 2022, and December 31, 2024. Patients were excluded from the study if they had a history of neck surgery, traumatic events, or injuries related to the cervical region.
Data was recorded from a thorough review of patient medical records to obtain demographic, clinical, and diagnostic information. These included data from digital motion X-ray (videofluoroscopy), cone beam computed tomography (CT), Doppler ultrasound, and tonometry.
Results
Analysis revealed that over 71% of patients reported at least 29 distinct symptoms. Nearly all participants exhibited a combination of forward head posture, reduced cervical curve depth, ligamentous cervical instability, and decreased cross-sectional area (CSA) of both the internal jugular vein and the vagus nerve. Notably, the vagus nerve cross-sectional area was significantly smaller in the hEDS group compared to healthy or normal populations. The internal jugular vein cross-sectional area was markedly reduced at the C1 vertebral level relative to C4–C5, indicating potential carotid sheath compression at C1.
- Over 90% of patients showed abnormal results in Ligamentous Cervical Instability C1–C2 lateral flexion, C6AI (C6-Atlas Angle/Index to assess forward head posture and spinal alignment), and curve depth.
- More than 95% exhibited signs of bilateral internal jugular vein stenosis and increased Optic nerve sheath diameter, while 100% had unusually small vagus nerve cross-sectional area, indicating nerve degeneration or atrophy.
- The significant occurrence and overlap of these structural issues and test results imply that these findings are probably not coincidental and suggest a potential mechanistic connection. We propose that these findings likely indicate cervical spine involvement, which contributes to the neurological and autonomic symptoms, as well as systemic issues often seen in hEDS.
- Hypermobile Ehlers–Danlos syndrome patients often experience a wide range of chronic and disabling symptoms, including not only musculoskeletal complaints, but also cardiovascular, neurological, gastrointestinal, and autonomic dysfunctions at a higher rate than the general population, all categories which were highly prevalent in this study.
Ligamentous facet joint cervical instability
Our study is the first to document ligamentous facet joint cervical instability at C1–C2 (LCI C1–C2) in a group of hEDS patients.
- In medical literature, atlantoaxial instability usually means ligamentous atlantodens (or central or medial atlantoaxial) instability, which describes how the atlas, dens, and medial joint are related, mainly held together by the transverse and alar ligaments.
- On the other hand, the atlantoaxial facet joints (left and right) are positioned laterally and supported by the capsular ligaments, so when they are injured, the condition is also called lateral atlantoaxial instability. It’s crucial to understand the difference between these two types of C1–C2 instability because atlantoaxial instability usually requires surgery, while atlantoaxial facet joint instability can often be managed with conservative treatments like chiropractic care, physiotherapy, and prolotherapy.
Vagus Nerve
This is the first instance of ultrasound vagus nerve CSA being reported in a group of patients with hEDS, which is a notably new discovery since all patients in this study showed signs of bilateral vagus nerve degeneration (atrophy).
The vagus nerves are highly vulnerable to compression and degeneration, which can be observed through ultrasound of the carotid sheath. A reduction in vagus nerve CSA has been linked to parasympathetic dysfunction, potentially explaining many of the symptoms experienced by this patient group. The vagus nerves are the primary nerves of the parasympathetic nervous system, making up 80–90% of its afferent fibers, and serve as the main inhibitor of sympathetic stimulation . If the vagus nerves degenerate or malfunction, leading to decreased vagal activity, this could result in a state dominated by sympathetic activity. An overactive sympathetic system and/or reduced parasympathetic activity can create a sympathovagal imbalance, which is observed in various brain and body diseases, including mental health issues. Damage to the vagus nerves or reduced vagal signaling can impair anti-inflammatory responses or lead to excessive production of inframammary cytokines. The potential for sympathetic dominance and heightened systemic inflammation may play a role in the wide range of symptoms experienced by hEDS patients, such as joint pain, gastrointestinal issues, fatigue, and more, due to the vagus nerves’ involvement in the brain–body connection and inflammation regulation.
More research from our center
More articles
Vagus nerve compression in the neck: Symptoms and treatments
Are Ehlers-Danlos Syndrome Headaches and Migraines Caused by Cervical Spine and Neck Instability?