38. Prioritization of realignment associated with superior clinical outcomes for surgical cervical deformity patients

Abstract

BACKGROUND CONTEXT Many patients are unable to undergo a major cervical deformity corrective surgery due to deformity severity, age, comorbidities, and overall frailty status. In order to optimize quality of life in patients with cervical deformity, there may be alignment targets to be prioritized. PURPOSE To prioritize the cervical parameter targets for alignment. STUDY DESIGN/SETTING Retrospective review of a multicenter prospective cervical deformity database. PATIENT SAMPLE Seventy-seven patients undergoing cervical deformity (CD) corrective surgery. OUTCOME MEASURES Cervical regional alignment parameters: cervical sagittal vertical axis(cSVA), cervical lordosis(CL), T1 Slope minus CL(TS-CL), chin brow vertical angle(CBVA), McGregor's slope(MGS), C2-T3 plumb line(C2-T3 SVA), C2-T3 angle, C2 Slope. Health-related quality of life measures: NDI. METHODS Included:CD patients (C2-C7 Cobb>10°, CL>10°, cSVA>4cm, or CBVA>25°) with full baseline (BL) and 1-year (1Y) radiographic parameters and NDI scores; patients with cervical or cervicothoracic Primary Driver Ames type. Patients with BL Ames classified as low CD for both parameters of cSVA( RESULTS Seventy-seven CD patients included (62.1yrs, 64%F, 28.8kg/m2). Average CCI: 0.94, 7% current smokers. By approach, anterior: 19.4%, posterior: 41.6%, combined approach: 39%. Mean anterior levels fused: 3.5, posterior: 8.3, total: 7.5. Average op time: 553.1min; mean EBL: 1128.1ccs. 41.6% met MCID for NDI. A backwards linear regression model including radiographic differences as predictors from BL to 1 year for meeting MCID for NDI demonstrated an R2 of 0.820 (p=0.032) included TS-CL, cSVA, MGS, C2SS, C2-T3 angle, C2-T3 SVA, CL. By primary Ames driver, 67.5% of patients were categorized as C, and 32.5% as CT. Ratios of change in predictors for MCID NDI patients (BL -1Y) for C driver patients: 260.8% MGS, 140.3% CL, 121.2% C2-T3 angle, 49.6% C2 slope, 41.1% cSVA, 20.5% TS-CL, 3.1%C2-T3 SVA. While correction in CT driver patients included: 168.7% CL, 93% MGS, 70.8% C2-T3 angle, 31.1% cSVA, 27.5% C2 slope, 24.9% TS-CL, 13.7% C2-T3 SVA. The ratios were not significant between the two groups(p>0.050). Decision tree analysis determined cut-offs for radiographic change, prioritizing in the following order (based upon ordinal regression values): a correction ≤42.5°C2-T3 angle (OR: 5.667[1.074-29.891], p=0.041), -31.76°C2 slope (OR: 3.2 [0.852-12.026], p=0.085), >-11.57mm cSVA (OR: 3.185[1.137-8.917], p=0.027), >-2.16° MGS (OR: 2.724[0.971-7.636], p=0.057). CONCLUSIONS Certain ratios of correction of cervical parameters contribute to improving neck disability. Specific cut-offs of radiographic differences from baseline to 1 year were found prioritizing C2-T3 angle, followed by cervical lordosis, C2 slope, C2-C7 plumb line, and McGregor's slope, all strongly associated with meeting the minimal clinically important difference for the neck disability index score. Prioritizing these radiographic alignment parameters will optimize patient-reported outcomes for patients undergoing cervical deformity surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.