Surgical anatomy of neurovascular structures related to ventral C1-2 complex: an anatomical study

Transoral odontoidectomy and ventral C1-2 stabilization are important surgical procedures, performed to decompress ventral spinal cord, and to stabilize craniovertebral junction. These procedures require knowledge regarding surgical anatomy of neurovascular structures ventral to the C1-2 complex. The aim of this study is to evaluate the relationships between neurovascular structures and bony landmarks in ventral atlantoaxial complex.

This study was performed on six formaldehyde fixed cadaveric head and neck specimens. Relevant anatomical parameters, including distances from the midsagittal line to internal carotid arteries (ICA), vertebral arteries (VA), and hypoglossal nerves (HN), were measured using electronic calipers.

The mean distance between ICA and midsagittal line was observed as 26.13 mm at the level of axis and 24.67 mm at the level of the atlas. The mean distance between VA and midsagittal line was observed as 15.38 mm at the level of axis and 26.54 mm at the level of the atlas. The mean distance between HN and midsagittal line was observed as 33.27 and 33.58 mm at the level of the atlas and axis, respectively.

This study confirmed that ICA and HN proceeded ventrally or laterally along the lateral aspect of the C1 lateral mass; therefore, the area located ventrally along the medial components of the C1 lateral mass was the safe zone for anterior surgical approach.