Cortical emissary vein: An important vessel to look for before bone anchored hearing aid implantation

Bone anchored hearing aid (BAHA) is a device that combines a sound processor with a small titanium fixture implanted at the mastoid area. It is indicated for those having conductive hearing loss, especially in those not suitable for hearing aids. Emissary veins are residual connections between intracerebral veins and their extracranial drainage. The vein may be injured at the time of drilling procedure such as during insertion of implant at the mastoid area. We report a case of difficult BAHA surgery after encounter with cortical emissary vein. Mastoid emissary vein is a rare but definite entity which if not diagnosed preoperatively could be a cause of severe hemorrhage intraoperatively.