This is a talk on vertebral artery injury and how to tackle it if it happens during craniovertebral surgery.
In brief, the vertebral artery can be injured in two locations:
Extraosseous injury (open space injury): The vertebral artery (VA) is vulnerable to injury above the C1 posterior arch and lateral to the atlantoaxial joints. Sometimes, there is an anomalous course of VA than can get injured. The bleeding tends to be torrential. The quickest way to stop bleeding is by using tamponade for about 20-30 minutes. Endovascular intervention may be required if the bleeding cannot be controlled. Ligation or repair of the VA in this region is technically quite challenging.
Intraosseous injury (in the screw hole): The VA is vulnerable to injury in the C2 pars especially if it has an anomalous course (high riding VA). The bleeding can be controlled by using bone wax and by inserting the screw. The opposite side has to be abandoned to prevent bilateral VA injury. Postoperative angiography may be needed to assess the damage or to detect ongoing bleeding.