This procedure can be used to achieve additional stability in osteoporotic bone when odontoid screw fixation alone is insufficient.
It generally serves as an alternative to posterior C1-C2 fusion, in particular when prone positioning is contraindicated.
The advantage of this screw is that it requires less muscle dissection than a posterior trans articular screw.
2. Preoperative evaluation
A preoperative CT image must be evaluated to determine if this screw is possible.
When C1-C2 screws are used as an adjunct to odontoid screws, then these screws are inserted using the same approach as the odontoid screws.
If these screws are used as a stand alone procedure, the standard anterolateral approach to the cervical spine is utilized for the insertion of anterior trans articular C1-C2 screws.
The surgery is performed withe the patient placed supine.
4. Screw insertion
Screw entry point
The starting hole for the screw is 7-8 mm distal to the C1-C2 joint.
It is 3-5 mm lateral to the medial boarder of the C1-C2 joint.
K-wires are inserted and directed approximately 30° laterally and 30° posteriorly across the joint.
Drill, tap, measure and insert the cannulated screws under fluoroscopic guidance (3.5 or 4.0 mm cortex screws, typically 15-20 mm long). The screw should not perforate the dorsal cortex of C1, nor should it violate the occipital cervical joint.
A radiolucent retractor is useful to visualize the joint.
K-wires are removed.
Patients are made to sit up in the bed on the evening following the operation.
A collar is commonly used following surgical stabilization to moderate patient activity.
The purpose of a collar is to prevent ranges of motion outside of limits deemed unfavorable for fracture healing. Collar is optional.
Patients with intact neurological status are made to stand and walk on the first day after surgery. Patients can be discharged when medically stable or sent to a rehabilitation center if further care is necessary. This depends on the comfort levels and presence of other associated injuries.
Patients are generally followed with periodical x-rays at 6 weeks, 3 months, 6 months, and 1 year.