Table 1

Summary of osseous anomalies and clinical presentation of 12 patients with occipitalization of the atlas.

Case No.Age (yrs), SexComorbidityFusion TypeHypoplastic Occipital CondyleAtlantoaxial JointVertebral FusionClinical Presentation
MedialLateral
151, Fpartialsubluxated (mobile)hyperreflexia, paresthesia (extremities), pain in the nape of the neck
247, Fcompletertsubluxated (irreducible)deformedC2-3hyperreflexia, paresthesia (occiput, extremities), motorweakness, gait disturbance
363, Mpartialsubluxated (irreducible)C5-6hyperreflexia, paresthesia (extremities), pain in the nape of the neck
456, Mcompletesubluxated (mobile)C2-3hyperreflexia, paresthesia (extremities), gait disturbance
563, Fcompleteltsubluxated (irreducible)C2-3hyperreflexia, paresthesia (occiput, extremities), gait disturbance
668, Fcompletesubluxated (irreducible)deformedC2-3hyperreflexia, paresthesia (extremities), gait disturbance
774, MChiari malformationpartiallthyperreflexia, paresthesia (extremities), gait disturbance
846, Mcompleteltsubluxated (irreducible)C2-3hyperreflexia, paresthesia (extremities), gait disturbance
977, Fcompletesubluxated (irreducible)C2-3hyperreflexia, paresthesia (extremities), gait disturbance
1066, Fpartialrtsubluxated (irreducible)hyperreflexia, paresthesia (extremities), gait disturbance
1162, FRAcompletehyperreflexia, paresthesia (occiput, extremities), motorweakness, gait disturbance
1245, FOPLLcompletehyperreflexia, paresthesia (extremities), motorweakness, gait disturbance