Exposure of posterior aspect of C1
Identify the midline of the posterior arch of C1.
Using a cobb elevator gently push the soft tissues subperiosteally off the posterior arch of C1. Review preoperative images to verify whether the tumor invades the lamina. In such cases, exposure of the posterior elements should be performed with great care and the use of Cobb elevators should be avoided.
If lateral mass screws of C1 are planned, the posterior ring is exposed all the way to the lateral border of the lateral mass.
Careful dissection is essential not to compromise the vertebral artery which lies only 1.5 cm lateral to the midline.