Orientation of C1-2 Joints in Congenital Atlantoaxial Dislocation
نویسنده
چکیده
Aim: To study the C1-2 facets in patients with congenital atlantoaxial dislocation and their bearing on the presentation and management. Materials and methods: Thirty-six patients of congenital AAD were studied in the last 2 years. Twenty-four patients had irreducible AAD (not reducing on traction) and remaining 12 had redu cible AAD. Computed tomography (CT) scans were obtained and the C1-2 joints were studied in axial, sagittal and coronal planes. The obliquity of (C1-2) joints was measured using the novel inferior C1 coronal and sagittal angles. The relationship of obliquity of joints, age and reducibility was studied and these were compared with normal subjects. The amount of facet to be drilled was decided by these angles. Direct posterior reduction was attempted by drilling the facets flat in all. Anomalous vertebral arteries (VA) were detected with preoperative CT angiograms and addressed appropriately intraoperatively. Results: The inferior C1 sagittal and coronal angles were significantly acute in patients with IrAAD as compared to those with RAAD and normal spine. An inferior sagittal angle more than 150o predicted reducibility. More acute the angle, younger was the age of presentation. Relatively acute coronal angles were noticed in patients with telescoping (central or vertical dislocation). Intraoperative reduction could be achieved after drilling the facets nearly flat. Anomalous VA were found in over 70% of the patients with CAAD and were appropriately addressed. The fusion rates were over 90%. Conclusion: The congenital AAD appears to be a dynamic process, progressing with time. The acuteness of the inferior C1 sagittal facet angles possibly determines the age at presen tation and reducibility. Coronal angle determines the teles coping of C2 within C1. Intraoperative reduction through a direct posterior approach can be achieved in patients with IrAAD by drilling the wedge of C1-2 facets to make the joints relatively flat. Comprehensive facetal drilling also increases the fusion rates.
منابع مشابه
Case of Atlantoaxial Dislocation with Assimilated C1, Absent Posterior C2, Butterfly C3, and Fused Subaxial Cervical Spine: Management Dilemma with Multiple Segmentation and Formation Defects
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