Research Fellow NYU Langone Medical Center Paterson, NJ, US
Introduction: It has not yet been determined whether intraoperative or immediate post-operative C2 slope and the magnitude of change from baseline correlate with postoperative health-related quality of life (HRQL) metrics and radiographic complications.
Methods: Included: operative CD patients with pre-(BL) and 2-year(2Y) data. Paired means comparison analysis and linear regression assessed the impact of absolute intraoperative/immediate postoperative (intra-op) radiographic measures and 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) and underwent surgery. 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 : This study demonstrates that intra-operative reduction in C2 slope of 44% or more from baseline 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.
