[Transpedicle screw fixation in upper cervical spine for treating atlantoaxial instability and dislocation].

OBJECTIVE

To explore the surgical feasibility and clinical outcome of transpedicle screw fixation in treatment of atlantoaxial instability and dislocation.

METHODS

From January 2007 to June 2009, 16 patients with atlantoaxial instability and dislocation were treated with transpedicle screw fixation. There were 13 males and 3 females, with a mean age of 42 years (range, 24-61 years). The transpedicle screw fixation was employed in 5 patients with old odontoid fracture (4 of Anderson type II and 1 of type III), in 4 patients with fresh odontoid fracture, in 4 patients with traumatic disruption of transverse atlantal ligament, and in 3 patients with congenital odontoid disconnection for atlantoaxial instability. All patients had symptoms of cervical pain and limiting of cervical motion, 10 patients complicated by dyscinesia and hypoesthesia of extremities. The Japanese Orthopaedic Association (JOA) score before operation was from 5 to 13, with an average of 8.5. The image examination showed atlantoaxial instability or dislocation in all patients. Granulated autogenous ilium (20-30 g) was placed onto the surface of the posterior arches of both atlas and axis in some patients with old fracture of odontoid process or disruption of transverse atlantal ligament.

RESULTS

The mean operative time and bleeding amount were 1.6 hours (1.2-2.5 hours) and 100 mL (50-200 mL), respectively. All the incision healed by first intension. All patients were followed up for 3-18 months, with an average of 11.5 months. The JOA score 3 months after operation was from 12 to 17, with an average of 14.2. All screws were successfully placed in atlas and axis. No postoperative complications such as vertebral artery injury, dural rupture, exacerbation of neurological symptoms, wound infection, and broken screws were observed in 16 cases. Postoperative radiograph and CT showed that only one screw penetrated into vertebral canal, but there was no neurological symptoms. Bony fusion was observed after 6 to 18 months of operation, and atlantoaxial rotational function in all patients restored satisfactorily, but axial rotation was partially lost.

CONCLUSION

Transpedicle screw fixation in upper cervical spine for treatment of atlantoaxial instability and dislocation is safe and reliable.