Posterior cervical fixation with nitinol shape memory loop in the anterior-posterior combined approach for the patients with three column injury of the cervical spine : preliminary report

Abstract

Objective: The authors reviewed clinical and radiological outcomes in patients with three column injury of the cervical spine who had undergone posterior cervical fixation using Nitinol shape memory alloy loop in the anterior-posterior combined approach.

Materials: Nine patients were surgically treated with anterior cervical fusion using an iliac bone graft and dynamic plate-screw system, and the posterior cervical fixation using Nitinol shape memory loop (Davydovtrade mark) at the same time. A retrospective review was performed. Clinical outcomes were assessed using the Frankel grading method. We reviewed the radiological parameters such as bony fusion rate, height of iliac bone graft strut, graft subsidence, cervical lordotic angle, and instrument related complication.

Results: Single-level fusion was performed in five patients, and two-level fusion in four. Solid bone fusion was presented in all cases after surgery. The mean height of graft strut was significantly decreased from 20.46+/-9.97 mm at immediate postoperative state to 18.87+/-8.60 mm at the final follow-up period (p<0.05). The mean cervical lordotic angle decreased from 13.83+/-11.84 degrees to 11.37+/-6.03 degrees at the immediate postoperative state but then, increased to 24.39+/-9.83 degrees at the final follow-up period (p<0.05). There were no instrument related complications.

Conclusion: We suggest that the posterior cervical fixation using Nitinol shape memory alloy loop may be a simple and useful method, and be one of treatment options in anterior-posterior combined approach for the patients with the three column injury of the cervical spine.

Keywords: Nitinol; Posterior cervical surgery; Shape memory loop; fracture fixation.

Fig. 1

Measurement of height of graft strut on neutral cervical lateral X-ray.

Fig. 2

Measurement of cervical lordotic angle on lateral X-ray.

Fig. 3

Imaging studies of a patient with left arm monoparesis after trauma. A : Plain cervical lateral X-ray of C4 vertebral body fracture. B and C : Magnetic resonance image and computed tomography show C4 vertebral body fracture with three column injury.

Fig. 4

A : Immediate postoperative lateral radiographs. B : Sixteen months later, lateral radiographs showing solid bone fusion and improvement of cervical lordotic angle.