Redefining cervical spine deformity classification through novel cutoffs: An assessment of the relationship between radiographic parameters and functional neurological outcomes
Peter Gust Passias1, Katherine E Pierce1, Avery E Brown1, Cole A Bortz1, Haddy Alas1, Renaud Lafage2, Virginie Lafage2, Breton Line3, Eric O Klineberg4, Douglas C Burton5, Robert Hart6, Alan H Daniels7, Shay Bess3, Bassel Diebo8, Themistocles Protopsaltis9, Robert Eastlack10, Christopher I Shaffrey11, Frank J Schwab2, Justin S Smith12, Christopher Ames13
1 Department of Orthopaedic and Neurologic Surgery, NYU Langone Orthopedic Hospital, New York Spine Institute, New York, NY, USA
2 Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA
3 Department of Spine Surgery, Denver International Spine Center, Presbyterian St. Luke's/Rocky Mountain Hospital for Children, Denver, Colorado, USA
4 Department of Orthopaedic Surgery, University of California, Davis, Davis, USA
5 Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, KS, USA
6 Department of Orthopaedic Surgery, Swedish Neuroscience Institute, Seattle, WA, USA
7 Department of Orthopaedic Surgery, Warren Alpert School of Medicine, Brown University, Providence, RI, USA
8 Department of Orthopaedic Surgery, SUNY Downstate Medical Center, New York, NY, USA
9 Department of Orthopaedics, NYU Langone Orthopedic Hospital, New York, NY, USA
10 Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, USA
11 Departments of Neurosurgery and Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
12 Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA
13 Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA
Peter Gust Passias
Departments of Orthopaedic and Neurological Surgery, Division of Spinal Surgery, NYU Langone Medical Center, Orthopaedic Hospital – NYU School of Medicine, New York Spine Institute, 301 East 17th Street, New York, NY, 10003
Source of Support: None, Conflict of Interest: None
Purpose: The aim is to investigate the relationship between cervical parameters and the modified Japanese Orthopedic Association scale (mJOA).
Materials and Methods: Surgical adult cervical deformity (CD) patients were included in this retrospective analysis. After determining data followed a parametric distribution through the Shapiro–Wilk Normality (P = 0.15, P > 0.05), Pearson correlations were run for radiographic parameters and mJOA. For significant correlations, logistic regressions were performed to determine a threshold of radiographic measures for which the correlation with mJOA scores was most significant. mJOA score of 14 and <12 reported cut-off values for moderate (M) and severe (S) disability. New modifiers were compared to an existing classification using Spearman's rho and logistic regression analyses to predict outcomes up to 2 years.
Results: A total of 123 CD patients were included (60.5 years, 65%F, 29.1 kg/m2). For significant baseline factors from Pearson correlations, the following thresholds were predicted: MGS (M:-12 to-9° and 0°–19°, P = 0.020; S: >19° and <−12°, χ2 = 4.291, P = 0.036), TS-CL (M: 26°to 45°, P = 0.201; S: >45°, χ2 = 7.8, P = 0.005), CL (M:-21° to 3°, χ2 = 8.947, P = 0.004; S: <−21°, χ2 = 9.3, P = 0.009), C2-T3 (M: −35° to −25°, χ2 = 5.485, P = 0.046; S: <−35°, χ2 = 4.1, P = 0.041), C2 Slope (M: 33° to 49°, P = 0.122; S: >49°, χ2 = 5.7, P = 0.008), and Frailty (Mild: 0.18–0.27, P = 0.129; Severe: >0.27, P = 0.002). Compared to existing Ames- International Spine Study Group classification, the novel thresholds demonstrated significant predictive value for reoperation and mortality up to 2 years.
Conclusions: Collectively, these radiographic values can be utilized in refining existing classifications and developing collective understanding of severity and surgical targets in corrective surgery for adult CD.