Jugular tubercle and vertebral artery/posterior inferior cerebellar artery anatomic relationship: a 3-dimensional angiography computed tomography anthropometric study.

OBJECTIVE

To evaluate structural variations of the jugular tubercles (JTs) and their relationships with the vertebral artery, the posterior inferior cerebellar artery (PICA), and the vertebrobasilar junction (VBJ).

METHODS

The depth, height, and width of the JTs were measured using 30 cadaveric basicranial specimens and 50 three-dimensional angiography computed tomographic (angio-CT) scans evaluating morphological variations between the 2 sides. Angio-CT analysis evaluated the relationships of the JTs with the vertebral arteries and the PICAs. The location of the VBJ with respect to the JT level in the coronal plane was evaluated.

RESULTS

In the cadaveric specimens, the mean JT depth ranged from 0.9 to 3.1 cm, the mean height ranged from 0.6 to 1.5 cm, and the mean width ranged from 0.4 to 1.2 cm. According to the 3-dimensional angio-CT scans, JT measurements ranged as follows: depth, 0.7 to 2.6 cm; height, 0.6 to 1.4 cm; and width, 0.3 to 1.2 cm. The vertebral artery was in close contact with the JT on the left side in 30% of cases and on the right side in 24% of the cases. On axial scans, the PICA origin was classified as anterior to the JT in 20.5% of patients on the left side and 17.4% on the right, at the JT level in 50% of patients on the left side and 45.7% on the right, and posterior to the JT in 29.5% of patients on the left side and 36.9% on the right. On coronal scans, the PICA origin was classified as superior to the JT in 13.6% of patients on the left side and 8.7% on the right, at the JT level in 54.6% of patients on the left side and 50% on the right, and inferior to the JT in 31.8% of patients on the left side and 41.3% on the right. In the coronal plane, the VBJ was located above the tubercles in 16 patients (32%), at the JT level in 28 patients (56%), and below the tubercles in 6 patients (12%).

CONCLUSION

A precise morphometric analysis of the JTs on 3-dimensional CT scans was quick and safe and showed significant variations in their size and shape. The relationship of the JT with vertebral artery and the PICA varied significantly, as well as with the VBJ location. Knowledge of these morphological variations can contribute to optimal preoperative surgical planning, minimizing retraction and reducing morbidity during extreme lateral infrajugular-transtubercular exposure surgery.