Internal jugular vein duplication: clinical significance for head and neck cancer ablative and reconstructive surgery.

We present the case of a 75-year-old patient with a T2N0Mo oral cancer, who underwent surgery for cancer ablation and reconstruction. Intraoperatively, a duplicate internal jugular vein (IJV) was identified. Both segments were preserved. The veins of the free radial forearm flap that was used to reconstruct the defect were anastomosed to tributaries of the anterior IJV segment. In this rare anatomical variation, the anterior segment of IJV lies medially/anteriorly to the sternocleidomastoid muscle which poses a risk of inadvertent injury during the early steps of the neck dissection (ND). The posterior segment is at risk of injury during developing levels II-III-IV of ND. It is important to preserve the anterior IJV segment as this receives all tributaries that can be used for end-to-end anastomosis for the free flap. Preoperative contrast computed tomography scan can aid in recognition of IJV duplication and help prepare the surgeon to adjust certain operative steps.