Are C1 screws needed in occipitocervical fusion for traumatic cervical spine injury?

INTRODUCTION

While C1 screws provide an additional fixation point in occipitocervical (OC) fusion, they are often skipped due to surgical feasibility. In patients undergoing OC fusion with atlantooccipital dissociation (AOD), we sought to evaluate the impact of skipping C1 screws on: (1) construct length, (2) perioperative outcomes, and (3) long-term outcomes.

METHODS

A retrospective cohort study was performed for patients with traumatic cervical injury with AOD requiring OC fusion from 2003 to 2022. The primary outcome was total levels of fusion. Perioperative outcomes included operative time, estimated blood loss, and postoperative infections. Long-term outcomes included mechanical complications and reoperation. Bivariate and multivariable linear regression controlling for age, sex, and body mass index was performed.

RESULTS

Ninety-two patients underwent OC fusion with AOD (mean age: 40.2 ± 17.2 years) with a median follow-up of 0.9 (interquartile range: 0.4-2.8) years, and 54 (58.7%) received C1 instrumentation. Instrumenting C1 led to decreased fusion levels (2.5 ± 0.8 vs. 3.8 ± 1.0, P < 0.001) but increased operative time (192.7 ± 68.8 vs. 166.3 ± 40.5 min, P = 0.032), blood loss (369.8 ± 424.8 vs. 167.0 ± 95.8 ml, P = 0.002), and postoperative infections (11.1% vs. 0.0%, P = 0.040). There was no difference in mechanical complications (1.9% vs. 2.6%, P = 1.000) or reoperation (5.6% vs. 7.9%, P = 0.688). Mechanical complications were screw loosening (50.0%), instrumentation failure (50.0%), and pseudarthrosis (50.0%). On multivariable linear regression, C1 instrumentation was independently associated with decreased levels fused (β = --1.06, 95% confidence interval = --1.56 - -0.67, P < 0.001).

CONCLUSION

In OC fusion for cervical trauma, 41% of patients did not receive C1 screws. Skipping C1 was associated with longer constructs but reduced operative time, blood loss, and infection, without affecting complication or reoperation rates, highlighting the trade-offs of skipping C1 fixation.