Review Question - QID 211685

This patient in question has undergone a C4-6 anterior cervical discectomy and fusion. During the lateral portion of the discectomy, the brisk bleeding encountered was secondary to an injury of the vertebral artery.

The vertebral artery is classically found in the transverse foramen of the cervical vertebra. However, the course of the vertebral artery is variable, most notably at the C6 foramen. Vertebral arteries can be intraforaminal or extraforaminal, and their variable course, especially their medial migration, exposes the artery to injury during lateral decompression near the uncovertebral joint.

Eskander et al. looked at vertebral artery anatomy using MRI on 250 patients. They identified three main groups of anomalies: intraforaminal anomalies with midline migration, extraforaminal anomalies (entering in the foramen at a different level), and arterial anomalies. They found that 7.6% of patients had midline migration of the vertebral artery, and 92% of vertebral arteries were in their transverse foramen at the C6 level. Ultimately, they concluded that vertebral artery anatomy needs to be carefully considered to avoid injury.

Currier et al. studied the anatomic relationship of the Internal Carotid artery (ICA) to C1 using CTs with contrast. They looked at 50 CTs with contrast to determine the distance of the ICA to C1, which was 2.88mm on the left and 2.89mm on the right. Finding that it was at moderate risk of injury in 46% of cases and high risk in 12% of cases. They concluded that in the case of anticipated C1 hardware placement, a CT w/ contrast should be performed to determine the ICA location.

Nassr et al. retrospectively reviewed 750 multilevel cervical spine decompression surgeries by a single surgeon to identify the risk of C5 palsy. 630 patients were included in the analysis, and they found that the mean incidence of C5 palsy was 6.7%, with a higher incidence in males and those who underwent laminectomy and fusion. Ultimately, they concluded that the incidence of C5 palsy was not statistically significant based on the surgical procedure.

Figure A is a post-operative lateral cervical radiograph following C4-6 anterior cervical discectomy and fusion (ACDF).

Incorrect Answers:
Answer 1: The External carotid artery can be injured during an anterior cervical spine approach but is found more superficially during the dissection, not lateral to the uncovertebral joints.
Answer 2: The internal Jugular vein is not at risk of injury during bone removal, laterally near the uncovertebral joint.
Answer 4: The internal carotid artery is at risk of injury during screw placement into C1, not in the subaxial cervical spine.
Answer 5: The external Jugular vein is not at risk of injury during bone removal, laterally near the uncovertebral joint.