Background
The proclivity to atlanto-axial instability (AAI) has been widely reported for conditions such as rheumatoid arthritis and Down syndrome. Similarly, we have found a higher-than-expected incidence of AAI in the hereditary connective tissue disorders. We demonstrate a strong association of AAI with manifestations of dysautonomia, in particular syncope and lightheadedness, and make preliminary observations as to the salutary effect of surgical stabilization of the atlanto-axial motion segment.
Methods
In an IRB-approved retrospective study, twenty subjects (16 women, 4 men) with hereditary connective tissue disorders had AAI diagnosed by CT. Subjects underwent realignment (reduction), stabilization and fusion of C1-C2 motion segment. All subjects completed pre-operative and postoperative questionnaires in which they were asked about performance, function and autonomic symptoms, including lightheadedness, pre-syncope, and syncope.
Results
All patients with AAI reported lightheadedness, and 15 had refractory syncope or pre-syncope despite maximal medical management and physical therapy. Postoperatively, subjects reported statistically significant improvement in lightheadedness (p=.003), pre-syncope (p=.006), and syncope (p=.03), and in the frequency (p < 0.05) of other symptoms related to autonomic function, such as nausea, exercise intolerance, palpitations, tremors, heat intolerance, gastroesophageal reflux, and sleep apnea.
Conclusions
This study draws attention to the potential for AAI to present with syncope or pre-syncope that is refractory to medical management, and for surgical stabilization of AAI to lead to improvement of these and other autonomic symptoms.
