Extracranial dural venous sinus-A rare vascular anomaly in a case of atlantoaxial instability

Cases of atlantonaxial instability usually are accompanied with bony and vascular aberrations which make the management of these cases challenging We report a rare and challenging case of an 8-year-old boy with atlantoaxial instability presenting with features of cervical myelopathy and CT angiogram revealing an extracranial course of the dural venous sinus which is a first of its kind to be present in cases of atlantoaxial instability along with an aberrant vertebral artery course in the V3 segment, occipitalisation of atlas and facet malalignment. The patient was managed with intraoperative reduction by traction and posterior occipitocervical fusion It is of utmost importance to actively look for venous and arterial anomalies while planning surgery on the supraaxial cervical spine as damage to these structures can have catastrophic consequences