| Objective The aim of this study was to evaluate the effectiveness, security and feasibility of minimally invasive percutaneous novel transpedicular lag-screw fixation which is specially designed by us for hangman’s fracture under the monitoring of intra-operative, three-dimensional image(O-arm).Methods Based on the traditional open surgery for Hangman’s fracture using transpedicular lag-screw fixation, during the period of July 2013~November 2014, eight patients received minimally invasive percutaneous novel transpedicular lag-screw fixation assisted by O-arm(6 male, 2 female), who were, according to the Levine-Edwards classification, divided as follows: type I fracture, three cases; type II, four cases; type IIa, one case. All patients underwent preoperative mouth-open and lateral views and CT scan reconstruction of cervical spine to understand the fracture classification, direction of fracture line and fracture displacement. Besides, MRI was also taken to evaluate the existence and severity of the spinal cord injury, as well as C2-3 discoligamentous. Skull traction was conventionally used for 3-5 days before operation, and bedside photograph was taken to assess the reduction of fracture, especially for patients with severe fracture displacement. The patient was operated in prone position, and the position of the skin entry point was beside the C2 spinous process with the distance of 3.0cm. Under monitoring of O-arm, guide pin was placed to the optimum entry point of screw and its trajectory was also defined with satisfaction. Two appropriate length of transpedicular lag screws designed for hangman’s fracture were inserted simultaneously pulling over the guide pins separately using the matching tools, making sure again all screws were satisfactory in position under O-arm monitor. The general condition, as well as spinal cord injury, was concerned after operation. Patients were permitted to ambulate with soft collar the day after surgery, unless contraindicated by their general condition. Plain x-rays were performed at postoperative 1, 3, 6 months and final visit, including mouth-open and lateral views. Additional dynamic lateral views and CT scan were also performed at three-month postoperatively to assess the fracture healing and location of screws. Clinical outcomes were evaluated using Neck Disability Index(NDI) scores and Visual analogue Scale(VAS) scores during preoperative and postoperative follow up period. Furthermore, complications, patient satisfaction and range of motion, including flexion-extension and axial rotation were also investigated at the final follow-up.Results Eight patients were observed for an average of 10.5 months, ranging from 6-18 months, and suffered from neither implant-related complications postoperative nor spinal cord injury or vertebral artery preoperative. The average operation time was 75min(50~120min). Beside one patient with pelvic fracture need brake on the bed strictly, the ambulation time of other 7 patients wearing soft collar was 2.0±1.41(d). All patients achieved solid fusion at 3-6 months, and screws were satisfactory in position. The VAS scores of postoperative 1 day, then 1, 3, 6 months and final follow-up were lower than preoperative VAS score. The differences of preoperative and each visit follow-up VAS scores were statistically significant(P<0.001). However, the differences of VAS scores at each postoperative visit were no significant(P>0.001). Furthermore, the NDI scores of postoperative 1, 3, 6 months and final follow-up were also lower than preoperative NDI score. The differences of preoperative and each visit follow-up NDI scores were statistically significant(P<0.001). Finally, all patients regained the satisfactory range of motion of cervical spine, and the patient satisfaction was as high as to 9.38±0.74.Conclusion Percutaneous novel C2 transpedicular lag-screw fixation assisted by O-arm is an effective, safe, simple and reliable technique for hangman’s fracture. |
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