Posterior Circulation Ischemic Stroke From Atlantoaxial Instability and Lateral Dislocation due to Os Odontoideum: Case Report and Review of Literature

Abstract

Background: Strokes in young individuals often stem from unusual causes. Posterior circulation ischemic stroke caused by vertebral artery insufficiency due to atlantoaxial instability or dislocation is rare. We present a case of posterior circulation ischemic stroke due to an unstable os odontoideum and review the current literature. The clinical features and imaging manifestations are described to promote awareness of etiology, early diagnosis, and assessment.

Case Presentation: A 24-year-old male presented with recurrent right-sided limb numbness and weakness and cerebellar ataxia due to posterior circulation ischemic stroke. The work-up revealed thrombosis reformation in the tortuous left vertebral artery. It is noteworthy that the patient developed compression and chronic damage of the vertebral artery secondary to atlantoaxial instability and lateral dislocation due to an os odontoideum. He underwent antiplatelet and anticoagulant therapy, cervical traction, and posterior atlantoaxial screw fixation and fusion with iliac crest autograft. The postoperative course was uneventful. At 6-month follow-up, the patient had a solid fusion mass and rigid stability of the atlantoaxial joint without neurologic deficits or ischemic sequelae.

Conclusions: For unexplained posterior circulation ischemic stroke, it is important to consider unstable os odontoideum as a potential etiology, especially in pediatric and young adult male patients. Atlantoaxial instability and dislocation with os odontoideum, especially when occurring laterally, may cause insufficiency of the vertebral artery and subsequent posterior circulation ischemic strokes. The significance of lateral atlantoaxial dislocation in the genesis of vertebral artery injury and the necessity for specific positional imaging are emphasized.

Keywords

atlantoaxial dislocation / atlantoaxial instability / os odontoideum / posterior circulation ischemic stroke / vertebral artery

References

[1] Á. Merwick and D. Werring, “Posterior Circulation Ischaemic Stroke,” BMJ 348 (2014): g3175,

[2] F. Schöberl, P. A. Ringleb, R. Wakili, S. Poli, F. A. Wollenweber, and L. Kellert, “Juvenile Stroke: A Practice-Oriented Overview,” Deutsches Ärzteblatt International 114, no. 31–32 (2017): 527,

[3] B. Arvin, M. P Fournier-Gosselin, and M. G. Fehlings, “Os Odontoideum: Etiology and Surgical Management,” Neurosurgery 66, no. 3 (2010): A22–A31,

[4] B. J. McHugh, R. A. Grant, A. B. Zupon, and M. L. DiLuna, “Congenital Os Odontoideum Arising From the Secondary Ossification Center Without Prior Fracture,” Journal of Neurosurgery: Spine 17, no. 6 (2012): 594–597,

[5] J. W. Fielding and P. P. Griffin, “Os odontoideum: An Acquired Lesion,” Journal of Bone and Joint Surgery: American Volume 56 (1974): 187–190.

[6] S. Cho, N. A. Shlobin, and N. S. Dahdaleh, “Os Odontoideum: A Comprehensive Review,” Journal of Craniovertebral Junction and Spine 13, no. 3 (2022): 256–264,

[7] I. J. Helenius, J. M. Bauer, B. Verhofste, et al., “Os Odontoideum in Children: Treatment Outcomes and Neurological Risk Factors,” Journal of Bone and Joint Surgery 101, no. 19 (2019): 1750–1760,

[8] W. D. Singer, J. S. Haller, and S. M. Wolpert, “Occlusive Vertebrobasilar Artery Disease Associated With Cervical Spine Anomaly,” American Journal of Diseases of Children 129, no. 4 (1975): 492–495,

[9] Z. Chen, F. Z. Jian, and K. Wang, “Diagnosis and Treatment of Vertebral Artery Dissection Caused by Atlantoaxial Dislocation,” CNS Neuroscience & Therapeutics 18, no. 10 (2012): 876–877,

[10] H. Vupputuri, E. J. Gandham, S. A. Mani, K. P. Raju, S. Aaron, and A. G. Chacko, “Dynamic Imaging of the Craniovertebral Junction Is Mandatory in Patients With Posterior Circulation Strokes,” European Spine Journal 29, no. 5 (2020): 1078–1086,

[11] V. Sawlani, S. Behari, P. Salunke, V. K. Jain, and R. V. Phadke, ““Stretched Loop Sign” of the Vertebral Artery: A Predictor of Vertebrobasilar Insufficiency in Atlantoaxial Dislocation,” Surgical Neurology 66, no. 3 (2006): 298–304,

[12] M. K. Morgan, B. M. Onofrio, and C. E. Bender, “Familial Os Odontoideum: Case Report,” Journal of Neurosurgery 70, no. 4 (1989): 636–639,

[13] E. L. Spierings and R. Braakman, “The Management of Os Odontoideum. Analysis of 37 Cases,” Journal of Bone & Joint Surgery: British Volume 64-B, no. 4 (1982): 422–428,

[14] L. Dai, W. Yuan, B. Ni, and L. Jia, “Os Odontoideum: Etiology, Diagnosis, and Management,” Surgical Neurology 53, no. 2 (2000): 106–108; discussion 108–109,

[15] A. Goel, A. Patil, A. Shah, S. Dandpat, S. Rai, and S. Ranjan, “Os Odontoideum: Analysis of 190 Surgically Treated Cases,” World Neurosurgery 134 (2020): e512–e523,

RIGHTS & PERMISSIONS

2024 The Author(s). Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.