Examination of the related factors of the C2/3 nonunion at 5 years after cervical multilevel posterior decompression and fusion using C2 pedicle screws preserving three muscles inserted at C2

Abstract

We conducted a 5-year follow-up evaluation of 26 cases who underwent C2-T1 posterior decompression and fusion surgery from 2013 to 2016. The fusion rate at C2/3 was notably low at 46% compared to other intervertebral levels. We categorized patients who achieved fusion at C2/3 within 5 years postoperatively as the Fusion group (F group: 12 cases) and those who did not as the Non-Fusion group (NF group: 14 cases). The NF group was younger, and having a larger preoperative C2-7 range of motion compared to the F group, and they had a higher proportion of C5 pedicle screw (PS) usage as a mid-cervical anchor relative to C4-6 lateral mass screws. Additionally, C2 PS loosening (5 cases) occurred in only the NF group, and there was no significant postoperative improvement in EuroQol-5 Dimension Questionnaire scores in the NF group. It is considered crucial to adopt intraoperative techniques to prevent non-fusion at C2/3 and to identify patients at high risk of non-union in advance.