Posterior atlantoaxial facet screw fixation

Area of Science:

• Neurosurgery
• Orthopedic Surgery
• Spinal Surgery

Background:

• Atlantoaxial instability (C1-2 instability) presents a significant challenge in spinal surgery.
• Common causes include trauma, rheumatoid arthritis, neoplasms, and os odontoideum.
• Previous C1-2 fixation methods like wire and graft have shown limitations, including nonunion.

Purpose of the Study:

• To evaluate the efficacy of posterior atlantoaxial facet screw fixation for achieving immediate rigid C1-2 fixation.
• To assess the fusion rates and complications associated with this technique.
• To compare the mechanical superiority of facet screw fixation over traditional methods.

Main Methods:

• Eighteen patients with atlantoaxial instability underwent posterior atlantoaxial facet screw fixation.
• Fixation was augmented with an interspinous C1-2 strut graft wired in place for three-point stabilization.
• Follow-up ranged from 6 to 16 months, with a mean of 12 months.

Main Results:

• All 18 patients achieved satisfactory fixation and restored C1-2 alignment and stability without instrumentation complications.
• Seventeen of 17 surviving patients developed osseous unions.
• One patient died postoperatively from metastatic disease, with intact spinal fixation.

Conclusions:

• Posterior atlantoaxial facet screw fixation provides immediate, multidirectional, rigid C1-2 fixation.
• This technique is mechanically superior to wiring or clamp fixation and maximizes fusion success.
• It is particularly useful for treating pseudoarthrosis and eliminates the need for external orthoses.