Introduction: While Chiari I malformations are well described in the literature, there are no studies that directly investigate the role of race, gender, and socioeconomics on presentations and outcomes.

Methods: The authors retrospectively reviewed the charts of 638 adult patients with the diagnosis of Chiari 1 malformation. Of these, 287 patients were included in the study. Race, gender, insurance status, individual symptoms, combinations of symptoms, depth of cerebellar tonsillar herniation, and presence of syringomyelia were examined as covariates in multivariate logistic regression models to identify independent predictors of presentation and outcome.

Results: Patients with public insurance tended to be older (P=0.01), were more likely to be African American (P<0.01), and had a longer length of stay in the hospital (P=0.01). There were a higher proportion of males who presented with upper extremity weakness (P=0.01), lower extremity weakness (P=0.040), and cranial nerve findings (P=0.02). Males also had shorter onset to diagnosis times (P=0.02), worse tonsillar herniation (P=0.03), and more severe symptoms (P=0.05). Caucasians more frequently presented with back pain (P=0.03), and African Americans more frequently presented with lower extremity weakness (P=0.01). African American patients were also found to have worse tonsillar herniation (P<0.01) and were more likely to present with syringomyelia (P=0.01). A multivariate regression analysis revealed that back pain (P<0.01), upper extremity weakness (P=<0.01), upper extremity paresthesias (P<0.01), and upper with lower extremity paresthesias (P=0.04) were significant predictors of syringomyelia. Predictors of operative intervention included typical headache (P<0.01), typical headache with upper extremity paresthesias (P=0.01), typical headache with neck pain (P=0.02), upper and lower extremity paresthesias (p=0.04), typical headache with dizziness (P=0.02), and worse tonsillar herniation (P<0.01). The only independent predictor of outcome was size of tonsillar herniation (P=0.03).

Conclusions: Significant differences in the presentation of Chiari 1 malformation due to gender, race, and insurance status were quantified for the first time.

Patient Care: Helping patients with Chiari malformations can be challenging because of uncertainty regarding how presenting symptoms may or may not relate to tonsillar herniation. It can be difficult to predict which patients might improve after surgical decompression and which ones will not. To the best of our knowledge, there have been no adult studies that examine racial or socioeconomic factors that may account for some of the variability in clinical presentation. Ideally, this study will help inform physicians when advising Chiari patients regarding presentation, prognosis, and treatment options.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) describe the importance of gender, race, and socioeconomic status on the presentation and outcomes of adult Chiari malformations; 2) discuss in small groups how these results can be explained and whether current assessment and management strategies should be altered; and 3) identify ways to improve current treatment plans for patients with adult Chiari 1 malformations

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