Axis pedicle screwing assisted by intraoperative 3-D navigation versus freehand axis pedicle screwing in treatment of Hangman fracture / 中华创伤骨科杂志

ABSTRACT

Objective:To compare the therapeutic results between axis pedicle screwing assisted by intraoperative 3-D navigation and freehand axis pedicle screwing in the treatment of Hangman fracture.Methods:A retrospective analysis was performed of the 64 patients with Hangman fracture who had received posterior axis pedicle screwing at Department of Spinal Surgery, The Sixth Hospital of Ningbo from May 2014 to December 2019. According to the placement methods of axis pedicle screws, they were divided into a navigation group ( n=34, subjected to axis pedicle screwing assisted by intraoperative 3-D navigation) and a freehand group ( n=30, subjected to freehand axis pedicle screwing). Pedicle screw placement time, operation time, intraoperative bleeding, fluoroscopy time, hospital stay, total hospitalization cost and complications were recorded and compared between the 2 groups. The accuracy of axis pedicle screw placement was evaluated according to the postoperative cervical CT and screw grading criteria proposed by Park et al. At admission, 3 months postoperation, and the last follow-up, neurological function of the patients was evaluated by modified Japanese Orthopedic Association (mJOA) score, neck pain was evaluated by visual analogue scale (VAS), and C2/3 vertebral body angulation and C2 forward displacement were measured. The clinical efficacy was evaluated by Moon grading at the last follow-up. Results:The navigation group and the freehand group were comparable due to insignificant differences between them in the preoperative general data ( P>0.05). The accuracy of screw placement in the navigation group (98.2%, 54/55) was significantly higher than that in the freehand group (85.2%, 46/54) ( P<0.05). The screw placement time, operation time, fluoroscopy time and total hospitalization cost in the navigation group were significantly more than those in the freehand group ( P<0.05). Vertebral artery injury occurred in 3 cases in the freehand group. Screw loosening, screw breakage or rod breakage occurred in none of the patients after operation. There was no significant difference between the 2 groups in the intraoperative bleeding, hospital stay or follow-up time ( P>0.05). In both groups, the VAS score, mJOA score, C2/3 vertebral body angulation and C2 forward displacement were significantly improved at 3 months postoperation and the last follow-up compared with those at admission ( P<0.05), but there was no significant difference between the 2 groups in the contemporary comparisons ( P>0.05). At the last follow-up, Moon grading in the navigation group was significantly better than that in the freehand group ( P<0.05). Conclusion:In the treatment of Hangman fracture, compared with freehand screw placement, axis pedicle screwing assisted by intraoperative 3-D navigation can improve accuracy and safety of screw placement and reduce postoperative complications, leading to better clinical efficacy.