Q.  Identify the structures encountered in the ventral atlanto-axial stabilization approach.

A.     

1. Skin (incise from the caudal aspect of the laryngeal cartilages to the manubrium)
2. SQ fat and fascial tissues
3. Separate sternohyoideus mm from the laryngeal cartilages to the cranial extent of the sternocephalicus mm, and bluntly dissect through the facial plane to the right of the trachea.  Be careful to not damage the right caudal thyroid artery and caudal thyroid vein.  You may have to cauterize the smaller branching vessels.  The esophagus should be identified and retracted to the left.  The recurrent laryngeal nerve will also be seen to the left along the trachea.  The carotid sheath should be identified and retracted to the right. 
4. The sternothyroideus muscle should be identified.  It may be able to re retracted or may need transection to give easier access to the AA joint.  Take care to preserve the thyroid vessels. 
5. Identify the prominent ventral process of the first cervical vertebra. 
6. Separate the longus colli muscles from the underlying atlas and axis (take care not to cause too much bone movement)
7. Identify and incise the joint capsule between the atlas and axis. 
8. Carefully position the C2 into proper position, scarify the vertebral end plates, and remove any dens that may be present. 
9. Be able to identify the joint articulations for implant placement, the atlas or alar notch for implant direction (to avoid the large vertebral vessels and C1 nerve roots)
10. UMN to the spinal cord segments responsible for LMN control of the phrenic runs through this area from the brainstem.  Injury to the neural tissue can lead to hypoventilation or catastrophic respiratory failure.