P110. Redefining cervical spine deformity classification through novel cut-offs: an assessment of the relationship between radiographic parameters and functional neurological outcomes

Abstract

BACKGROUND CONTEXT The current proposed cervical deformity (CD) classification system including cutoffs for C2-C7 sagittal vertical axis(cSVA), T1 slope minus C2-C7 lordosis (TS-CL), Chin Brow Vertical Angle (CBVA), and the modified Japanese Orthopaedic Association scale(mJOA) are based upon a modified Delphi approach and expert opinion. PURPOSE To investigate the relationship between cervical parameters and the Health Related Quality of Life (HRQL) measure, mJOA. STUDY DESIGN/SETTING Retrospective review of a prospective, consecutively enrolled CD database. PATIENT SAMPLE A total of 123 CD patients. OUTCOME MEASURES CD modifiers; HRQL Instrument: mJOA; Radiographic thresholds for moderate (M) and severe (S) deformity. METHODS Included: surgical adult CD patients (C2-C7 Cobb>10°, CL>10°, cSVA>4cm, or CBVA>25°). Radiographic parameters measured: C2-C7 lordosis (CL), T1 slope, C2-C7 SVA, TS-CL, C2-T3 angle, C2 slope, pelvic tilt (PT). Measured HRQLs: Reported mJOA scores, categorized by Tetreault et al.: 18 as none, 15-17 as mild, 12-14 as moderate and 0.05), Pearson correlations were run for all combinations. For significant correlations, linear and binary logistic regressions were performed to determine a possible threshold of radiographic measures for which the correlation with mJOA scores was most significant. A mJOA score of 14 and RESULTS A total of 123 CD patients were included (60.5±10.1 years, 65% female, 29.1±8.2 kg/m2). The average Charlson Comorbidity Index (CCI) score was 0.90. Cohort surgical factors included, by approach, 17.1% anterior, 50.4% posterior and 32.5% combined. Average anterior levels fused was 3.36, while the average posterior levels fused was 8.93, and the total average was 8.05 levels fused. The mean total operative time was 534.3 minutes, with an estimated blood loss (EBL) of 890.6 ccs. Baseline mJOA score was 13.54±2.8. Pearson correlations determined significant correlation between baseline mJOA scores and McGregor's Slope (-0.236, p=0.015), TS-CL (-0.246, p=0.006), CL (0.225, p=0.012), C2-T3 (0.180, p=0.046), C2 Slope (-0.234, p=0.009), and frailty (0.517, p 19° and 45°, x2= 7.8, p=0.005), CL (M: -21° to 3°, x2= 8.947, p=0.004; S: >3°, x2 =9.3, p=0.009), C2-T3 (M: -35° to -25°, x2 = 5.485, p=0.046; S: >-25°, x2 = 4.1, p=0.041), C2 Slope (M:33°to 49°, p=0.122; S: >49°, x2=5.7, p=0.008), and Frailty (Mild: 0.18 to 0.27, p=0.129; Severe: >0.27, p=0.002). CONCLUSIONS Novel thresholds were established for McGregor's Slope, TS-CL, C2-T3 angle, C2 Slope and frailty. Each correlated with moderate or severe neurologic myelopathy HRQL by way of mJOA score. These cut-off values can be utilized in classifying cervical deformity. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.