Lateral atlanto-axial joint access using the C2 pedicle

Neck pain and headaches can arise from the lateral atlanto-axial (LAA) joint. This pain can be diagnosed with intra-articular injections of local anesthetic. A widely used technique for access to the lateral atlanto-axial joint uses a posterior approach, but this approach can be hazardous because of the proximity of the vertebral artery, the dural sac, and the C2 spinal nerve and dorsal root ganglion.

The objective was to describe and test a new technique for accessing the LAA joint that avoids structures that lie behind the joint.

The new technique was described and tested for tolerance in 10 patients with unilateral suboccipital pain and tenderness over the LAA joint, along with evidence of LAA joint arthropathy on SPECT CT. The technique requires inserting a needle along a trajectory tangential to the dorsal surface of the C2 lamina. It involves obtaining a declined view of the C2 lamina and C2 pedicle.

In all cases, the C2 pedicle was easily identified and allowed the needle to pass asymptomatically underneath the neurovascular structures behind the joint. The tactile response of the lamina of C2 provided important feedback regarding needle depth caudal to the LAA joint.