Is it better to stop at C2 or C3/4 in elective posterior cervical decompression and fusion?

STUDY DESIGN Retrospective cohort study. OBJECTIVE a) Compare operative variables, complications, and patient-reported outcomes (PROs) in patients with an upper instrumented vertebrae (UIV) of C2 vs. C3/4, and b) assess outcomes based on C2 screw type. SUMMARY OF BACKGROUND DATA When performing elective posterior cervical laminectomy and fusion (PCLF), spine surgeons must choose the upper instrumented vertebrae (UIV) at the subaxial cervical spine (C3/4) versus C2. Differences in long-term complications and PROs remain unknown. METHODS A single-institution, retrospective cohort study from a prospective registry was conducted. All patients undergoing elective, degenerative PCLF from 12/2010-06/2018 were included. Patients were divided into a UIV of C2 vs. C3/4. Groups were 2:1 propensity matched for fusion extending to the thoracic spine. Demographics, operative, perioperative, complications, and 1-year PRO data were collected. RESULTS 117 patients underwent elective PCLF and were successfully propensity matched (39 C2 vs. 78 C3/4). Groups were similar in fusion extending to the thoracic spine (p = 0.588). Expectedly, the C2 group had more levels fused (5.63 ± 1.89) compared to the C3/4 group (4.50 ± 0.91) (p = 0.001). The C2 group had significantly longer operative time (p < 0.001), yet no differences were seen in estimated blood loss (EBL) (p = 0.494) or length of stay (LOS) (p = 0.424). Both groups significantly improved all PROs at 1-year (EQ-5D; NRS-NP/AP; NDI). Both groups had the same percentage of surgical adverse events at 6.8% (p = 1.00. Between C2 screw type, no differences were seen in operative time, EBL, LOS, complications, or PROs. CONCLUSIONS In patients undergoing elective PCLF, those instrumented to C2 had only longer operative times compared to those stopping at C3/4. No differences were seen in EBL, LOS, 1-year PROs, and complications. Type of C2 screw had no impact on outcomes. Besides increased operative time, instrumenting to C2 had no detectable difference on surgical outcomes or adverse event rates.Level of Evidence: 3.