Safe trajectory for an occipital condyle screw: A computer simulation study

Area of Science:

• Neurosurgery
• Orthopedic Surgery
• Medical Imaging

Background:

• Occipital condyle screw (OCS) fixation is a crucial technique for occipital-cervical fusion.
• Assessing the safety and feasibility of OCS placement is vital for surgical success and minimizing complications.

Purpose of the Study:

• To evaluate the feasibility of posterior occipital condyle screw (OCS) placement.
• To analyze the safe trajectory area for OCS insertion in the occipitocervical region.

Main Methods:

• Computed tomographic angiography scans of 73 patients were analyzed.
• The vertebral artery (VA)-occiput distance and occipital-atlas angulation were measured to determine feasibility.
• Simulated placement of 3.5 mm OCS was performed to calculate the probability of anatomical structure breach.

Main Results:

• OCS placement was feasible in 91.1% of occipital condyles, with higher feasibility in males (95.7%) than females (83.3%).
• Significant risks of injury to the hypoglossal canal (81.2%) and occipital-atlas joint (59.4%) were noted.
• Feasibility and screw range of motion were greater in males and patients with occipitocervical kyphosis (>5°).

Conclusions:

• Posterior occipital condyle screw (OCS) placement is a feasible technique for occipital-cervical fusion.
• Males and individuals with occipitocervical kyphosis demonstrate increased space for OCS placement.
• Tangent angulation is a potentially valuable tool for accurate and safe OCS insertion.