The Petrosquamosal Sinus: A Rare Vascular Variant Encountered During Cochlear Implantation Surgery

The petrosquamosal sinus is a rare and almost unknown emissary vein of the temporal bone. It traverses the middle cranial fossa along the petrosquamosal fissure and connects dural sinuses with extracranial venous networks. It is known to undergo normal involution during fetal and early postnatal life, and therefore is rarely found in humans. When encountered during surgery, it can be a significant source of bleeding hindering proper visualization of important surgical landmarks. Here we report the case of a PSS, encountered in a child during cochlear implantation surgery. We discuss its clinical significance and impact on the surgical approach. Laryngoscope, 134:4111–4113, 2024 The petrosquamosal sinus (PSS) is a rare and almost unknown emissary vein of the temporal bone. It traverses the middle cranial fossa along the petrosquamosal fissure and connects dural sinuses with extracranial venous networks. It is known to undergo normal involution during fetal and early postnatal life, and therefore is rarely found in humans. When encountered during surgery, it can be a significant source of bleeding hindering proper visualization of important surgical landmarks. Here we report the case of a PSS, encountered in a child during cochlear implantation surgery. We discuss its clinical significance and impact on the surgical approach.