Os odontoideum (OO) is a rare craniocervical anomaly that is characterized by a round ossicle separated from the C2 vertebral body. With a controversial etiology and unknown prevalence in the population, OO may be asymptomatic or present in patients with myelopathic and neurological symptoms. In this literature review, we aimed to investigate epidemiology, embryology, pathophysiology, clinical presentation, and the role of diagnostic radiography in OO. By providing an overview of different management strategies, surgical complications, and postoperative considerations for OO, our findings may guide neurosurgeons in providing proper diagnosis and treatment for OO patients. A literature review was conducted using the PubMed, EMBASE, and Scopus databases. A search using the query “os odontoideum” yielded 4319 results, of which 112 articles were chosen and analyzed for insights on factors such as etiology, clinical presentation, and management of OO. The presentation of OO varies widely from asymptomatic cases to severe neurological deficits. Asymptomatic patients can be managed either conservatively or surgically, while symptomatic patients should undergo operative stabilization. Although multiple studies show different techniques for surgical management involving posterior fusion, the diversity of such cases illustrates how treatment must be tailored to the individual patient to prevent complications. Conflicting studies and the paucity of current literature on OO highlight poor comprehension of the condition. Further understanding of the natural history of OO is critical to form evidence-based guidelines for the management of OO patients. More large-center studies are thus needed to promote accurate management of OO patients with optimal outcomes.

Objective Atlas fractures are a common craniocervical injury, often resulting from trauma. However, diagnosis and management of atlas fractures continues to be the subject of controversy. We aimed to characterize the factors related to diagnosis of atlas fractures, delineate important considerations in selecting the optimal management for a patient with an atlas fracture, and compare outcomes of surgical and conservative management. Methods: We performed a systematic review using PubMed, Embase, and Scopus to identify articles that analyzed diagnosis and management of isolated atlas fractures published between 2013 and 2020. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full. Results: Of 305 resultant articles, 13 were included. C1:C2 ratio and lateral mass displacement (LMD) were used to predict transverse atlantal ligament (TAL) injury. Surgery promoted high fusion rates overall. Stable atlas fractures achieved high fusion rates with conservative management, while spinal fusion promoted greater fusion rates than halo vest immobilization management for unstable fractures. Visual Analog Scale scores, range of motion, and/or LMD improved after surgery. LMD increased for unilateral sagittal split fractures with TAL injury after conservative treatment. Conclusion: Stable atlas fractures can be sufficiently treated conservatively. Unstable atlas fractures can be managed both conservatively and surgically, while surgery is associated with favorable outcomes for unstable isolated atlas fractures. Future studies are necessary to further guide risk stratification and treatment approaches in management of the patients with isolated atlas fractures.

Background: Traumatic vertebral artery dissections (tVADs) occur in up to 20% of patients with head trauma, yet data on their presentation and associated sequelae are limited. Aims and Objectives: To characterize the tVAD population and identify factors associated with clinical outcomes. Materials and Methods: We retrospectively analyzed all cases of tVAD at our institution from January 2004 to December 2018 with respect to mechanism of injury, clinical presentation, anatomic factors, associated pathologies, and relevant outcomes. Results: Of the 123 patients with tVAD, the most common presenting symptoms were neck pain (n=76, 67.3%), headache (57.5%), and visual changes (29.6%). 101 cases (82.1%) were unilateral, and 22 cases (17.9%) were bilateral. V2 was the most involved anatomic segment (83 cases, 70.3). 30 cases (25.4%) led to stroke, and 39 cases (31.7%) had a concomitant cervical fracture. The anatomic segment and number of segments involved, and baseline clinical and demographic characteristics were not associated with risk of stroke. Patients with associated fractures were older (50.3 years v. 36.4 years, p=0.0233), had a higher comorbid disease burden (CCI 1 vs. CCI 1, p<0.0007), were more likely to smoke (OR 3.0 [1.2178, 7.4028], p=0.0202), be male (OR 7.125 [3.0181, 16.8236], p<0.0001), and have mRS≥3 at discharge (OR 3.0545 [1.0937, 8.5752], p=0.0449). On multivariable regression, only fracture independently predicted mRS≥3 at discharge (OR 5.6898 [1.5067, 21.4876], p=0.010). Conclusion: tVADs may be associated with stroke and/or cervical fracture. Presenting symptoms predict stroke, but baseline demographic and clinical characteristics do not. Comorbid cervical fractures, not stroke, drive negative outcomes