gms | German Medical Science

Objective: C2 transpedicular screw fixation is a new technique that has not yet gained routine use in subaxial cervical spine instrumentation. We describe the technique, accuracy of placement and complications after transpedicular C2 pedicle screw fixation without neuronavigation.

Methods: Patients operated by C2 pedicle screw fixation, using a cannulated screw-rod-system were identified from the surgical logbook of the department. Clinical data were extracted retrospectively from the patients’ charts. Pedicle screw placement accuracy was assessed on postoperative CT scans according to Gertzbein and Robbins [1].

Results: 23 patients were included in the study. The mean age of the patients was 56±22.4 years. 52.2% of them were female. 16 patients had suffered trauma, four patients suffered from degenerative disease, two patients from inflammations and one had metastatic disease. In these 23 patients 42 C2 transpedicular screws were inserted. In all cases the cranial and medial surfaces of the isthmus of C2 were prepared intraoperatively in order to achieve optimal visual orientation before insertion of the screws. Lateral fluoroscopy was additionally used. The postoperative CT findings showed a Gertzbein & Robbins grade I pedicle screw insertion accuracy in 52.4%, a grade II in 28.6%, a grade III in 9.5%, a grade IV in 7.1%, and a grade V in 2.4%. In 3 patients (13%) a postoperative angiography was performed to exclude vertebral artery affection, because of a gross penetration of the screw into the vertebral artery canal (Gertzbein & Robbins grade III and IV). One patient was revised for screw replacement, due to a compression of the vertebral artery. As the sole hardware failure, screw pull out occurred in 8.7% of the cases. These were revised. Other complications attributable to screw placement did not occur. A multiple regression analysis showed a correlation of suboptimal screw insertion with the affection of the vertebral artery canal (p<0.001).

Conclusions: Careful surgical technique is necessary to avoid a vertebral artery injury in C2 pedicle screw fixation. However, a slight opening of the vertebral artery canal (Gertzbein & Robbins ≤ grade III) does not seem to put the artery at risk.