Isocentric C-arm 3D navigation versus conventional C-arm fluoroscopy for placement of C1 lateral mass and C2 pedicle screws in treatment of atlantoaxial instability

Abstract

Objective To compare the isocentric C-arm 3-dimensional （lso-C 3D） navigation versus conventional C-arm fluoroscopy in terms of accuracy of placing CI lateral mass and C2 pedicle （C1LM-C2P） screws in the treatment of atlantoaxial instability. Methods Thirty patients with atlantoaxial instability were treated with fixation with CI I,M-C2P screws in our hospital from June 2006 to June 201 I. They were 16 men and 14 women, aged frnm 39 to 52 years （average, 45.6 years）. The Iso-C 3D navigation group had 14 patients and there were 16 patients in the conventional fluoroscopy group. The 2 groups were comparable in general clinical data （ P 〉 0.05） . The operation time, radiation time, intraoperative blood loss, insertion accuracy and Japanese Orthopaedic Association （JOA） score were recorded and compared between the 2 groups. Results There were no significant differences between the 2 groups in the mean operation time （132. 1 ±6.4 minutes versus 143.2 ±8.2 minutes） （ t = 1. 761, P =0. 093） . The mean radiation time for the lso-C 3D navigation group （46.8 ± 1.4 seconds） was significantly shorter than for the conventional fluo- roscopy group （65.2±2.9 seeomts）, the mean blood loss for the navigation group （305.6 ±50.8 mL） was significantly less than for the fluoroscopy group （472.4± 56. 1 mL）, the percentage of screws of grade 0 forthe navigation group （94. 6% ） was significantly higher than for the fluoroscopy group （82.8%） （ P 〈 0. 05 ） . The mean follow-up of 12.4 months revealed fracture union on cervical X-ray films 6 months post- operation. There were no significant differences between the 2 groups in the mean JOA score 6 months post- operation （15.2± 0. 2 points versus 15.3 ± 0. 3 points）, but there were significant differences between the preoperative and postoperative scores in the 2 groups （ P 〈 0.05）. Conclusion In the treatment of at- lantoaxial instability with fixation with C1LM-C2P screws, compared with conventional C-ann fluoroscopy, Iso-C 3D navigation can significantly improve the accuracy of screw placement and reduce intraoperative flu- oroscopic time and blood loss. Key words: Atlas; Axis; Surgery, computer-assisted; Bone nail