Accuracy Of Upper Cervical Pedicle Screw Placements:Comparing Using O-arm And C-arm

Objective: The purpose of this study was to evaluate the accuracy of inserting upper cervical pedicle screws between using intraoperative computed tomography(O-arm)and conventional fluoroscopy(C-arm).Summary of Background Data: Upper cervical pedicle screws are used for atlantoaxial instability owing to its great biomechanical stability.Surgical complications caused by screw malposition bring up concerns with the adjunct placing-screw techniques.The O-arm and C-arm can be used to place pedicle screws and verify screw position.Methods: From January 2015 to December 2016,62 C1-2 pedicle screws were placed in 23 patients with the use of O-arm without infrared navigation.The accuracy measure was based on the postoperative CT imaging.The level of pedicle screw position was classified into 4 grades.As a control,58 C1-2 pedicle screws were placed in 20 patients in C-arm group from January 2010 to December 2014.Results: In O-arm group,57 screws(91.9%)without any cortex perforation were considered as Grade 0;5 screws(8.1%)had a pedicle breach of less than 2 mm as Grade 1;and none as Grade 2 or Grade 3.In C-arm group,46 pedicle screws(79.3 %)were categorized as Grade 0.8 screws(13.8 %)were Grade 1,and 4 screws(6.9 %)were Grade 2.Grade 3 was not existent in our study.There were statistically significant differences between the two groups(P=0.04).Conclusions: Compared with the C-arm,the use of O-arm can effectively improve the accuracy of upper cervical pedicle screws.