Are C1 Screws Needed in Occipitocervical Fusion for Traumatic Cervical Spine Injury?

Introduction: In occipitocervical (OC) fusion, while C1 screws provide an additional fixation point for fusion, C1 is often skipped due to surgical feasibility. For patients undergoing OC fusion for traumatic cervical injury, we sought to evaluate the impact of skipping C1 screw 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 requiring OC fusion from 2003-22. The primary outcome was total number of instrumented levels. Perioperative outcomes included operative time, estimated blood loss, and length of stay. Long-term outcomes included mechanical complications and reoperation. Descriptive, bivariate and multivariate statistics were performed.

Results: 160 patients underwent OC fusion, with a mean age of 48.5 ± 20.9-years, and mean follow-up of 1.9 ± 2.7 years. C1 screws were skipped in 92 patients (57.5%). The no C1-screw group had longer overall constructs (3.9±1.2 vs. 3.4±0.9,p=0.009) and more instrumented cervical levels (2.8±1.0 vs. 1.4±0.8,p=0.013). Patients without C1-screws had shorter surgery (167.9±51.3min vs. 191.5±68.4min, p=0.025), less blood loss (185.2±182.6cc vs. 344.0±388.6cc, p=0.003), decreased postoperative infections (2.2% vs. 11.8%, p=0.019), but significantly higher mechanical complications (12.1% vs 3.1%,p=0.047). Similar rates of reoperation (7.6% vs. 7.4%,p=0.952) were seen in both groups. Mechanical complications leading to reoperation were seen in 4 (33.3%) patients, of which 2 (16.7%) had pseudarthrosis. There was no significant difference in pain (7.6% vs 7.4%,p=0.422) at last follow-up. On multivariable logistic regression C1 instrumentation was an independent risk factor for postoperative infection (OR=7.75, 95%CI=1.29-46.50,p=0.025); however, the risk of mechanical complications in patients without C1 instrumentation lost significance of multivariable analysis (OR=0.54, 95%CI=0.23-1.24,p=0.540).

Conclusion :: In patients undergoing OC fusion for cervical trauma, 58% did not have C1 screws. While skipping C1 screws were associated with less operative time, decreased blood loss, and decreased infection, skipping C1 led to more levels fused and an increased risk of mechanical complications but not reoperation. These mixed results highlight the pros and cons of skipping C1 screws in OC fusion for traumatic cervical spine injury.