Surgical anatomy of the vertebral arteries

Study Design. This study compared direct measurements of the distances between the vertebral arteries in the cervical spines of human cadaver specimens with data obtained from axial computed tomography images of these specimens. Objective. To determine whether the information obtained from a computed tomography scan can be used reliably to predict the true anatomic location of the vertebral arteries and, in so doing, provide accurate guidelines for the lateral extent of anterior cervical decompressive procedures. Summary of Background Data. Iatrogenic vertebral artery injury during anterior cervical surgery is uncommon, potentially catastrophic, and avoidable. Methods. The means and standard deviation of measurements of the location of the cervical segment of the vertebral arteries obtained with high-precision, digital calipers by direct gross anatomic dissection of 16 adult (eight male, eight female) cadaver specimens were recorded. These measurements were compared with computed tomography scan data obtained on the same specimens. Results. The mean distances between the vertebral arteries progressively increased from C3 to C6. Computed tomography scan measurements of the distance between the cervical foramina transversaria were consistently smaller than direct measurements of the gross specimens. At C6, the computed tomography scan data were significantly less than the gross anatomic data. Conclusions. According to these data, computed tomography scan measurements may be used safely and accurately to plan the lateral extent of anterior cervical decompressive surgical procedures. Although the data obtained from the gross anatomic dissections may serve as guidelines to assist the surgeon, the authors recommend a careful review of the preoperative computed tomography scan on an individual case-by-case basis as the safest method to plan for anterior cervical surgery.