Research Fellow NYU Langone Health Paterson, New Jersey, United States
Introduction: Surgical correction of CD has been associated with superior alignment and functional outcomes. It has not been determined whether intraop C2S and T1 slope and the magnitude of change from BL correlate with HRQL metrics and risks of radiographic complication.
Methods: Included: operative CD patients with pre-(BL) and 2-year(2Y) data. Paired means comparison analysis and linear regression analysis assessed the impact of absolute intraoperative/immediate postoperative (intra-op) radiographic measures or BL-normalized changes in radiographic measures on post-op outcomes. Univariate and multivariate (MVA) regression and conditional inference tree (CIT) determine radiographic thresholds. Optimal outcome defined as: 1) meeting Virk et al. good clinical outcome criteria [≥2 of the following: NDI < 20 or meeting MCID, mild myelopathy (mJOA ≥14), NRS-Neck ≤5 or improved by ≥2 points from BL], and 2) for developing DJK or DJF by 2Y.
Results: 178 CD patients met inclusion criteria (61.2±10.5yrs, 63%F, BMI 29.0±7.5kg/m2, CCI: 1.00±1.31) and underwent surgery (mean levels fused 7.5±3.7, EBL 990mL, op time 547min). By approach, 19.3% anterior-only, 44.5% posterior-only, and 36.1% combined. Mean BL radiographic parameters: C2S: 31.18° C2-C7 lordosis 0.91°, T1S 29.03°, TS-CL 25.81°, cSVA 27.07mm. Between BL and intra-op, paired analysis revealed significant mean decrease in C2S (Δ-9.30°) and TS-CL (Δ-12.03°), as well as mean increase in CL (Δ+14.06°) (all p<.001). Between 1Y and 2Y, however, there was notable decrease in C2S (Δ-3.01°, p=.001), T1S (Δ-3.15°, p=.001), CL (Δ-7.18°, p=.015), and TS-CL (Δ-3.99°, p=.001). Between BL and intra-op, absolute reduction in C2S of >13.70° (43.94%) was associated with a decrease in DJF risk (p=.041). Lastly, patients who had improvement in cSVA at 6M were significantly more likely to achieve optimal outcome by 2Y (p=.013).
Conclusion : C2 slope has been previously identified as a critical radiographic marker in adult cervical deformity surgery, yet there is a paucity of literature focused on intraoperative or immediate post-operative C2S correction. This study demonstrates that intraoperative reduction in C2S of 44% or more from BL is significantly associated with reduced risk of distal junctional failure at 2Y, though other post-operative radiographic parameters also play a crucial role in predicting catastrophic outcomes and should be assessed in tandem.
