UCSF

Background

To optimize quality of life in patients with cervical deformity (CD), there may be alignment targets to be prioritized.

Objective

To prioritize the cervical parameter targets for alignment.

Methods

Included: CD patients (C2-C7 Cobb >10^°°, C2-C7 lordosis [CL] >10^°°, cSVA > 4 cm, or chin-brow vertical angle >25^°°) with full baseline (BL) and 1-year (1Y) radiographic parameters and Neck Disability Index (NDI) scores; patients with cervical (C) or cervicothoracic (CT) Primary Driver Ames type. Patients with BL Ames classified as low CD for both parameters of cSVA (<4 cm) and T1 slope minus CL (TS-CL) (<15^°°) were excluded. Patients assessed: Meeting Minimal Clinically Important Difference (MCID) for NDI (<-15 ΔNDI). Ratios of correction were found for regional parameters categorized by Primary Ames Driver (C or CT). Decision tree analysis assessed cut-offs for differences associated with meeting NDI MCID at 1Y.

Results

Seventy-seven CD patients (62.1 years, 64%F, 28.8 kg/m²). 41.6% met MCID for NDI. A backward linear regression model including radiographic differences as predictors from BL to 1Y for meeting MCID for NDI demonstrated an R ²= 0.820 (P = 0.032) included TS-CL, cSVA, MGS, C2SS, C2-T3 angle, C2-T3 sagittal vertical axis (SVA), CL. By primary Ames driver, 67.5% of patients were C, and 32.5% CT. Ratios of change in predictors for MCID NDI patients for C and CT were not significant between the two groups (P > 0.050). Decision tree analysis determined cut-offs for radiographic change, prioritizing in the following order: ≥42.5^° C2-T3 angle, >35.4^° CL, <-31.76^° C2 slope, <-11.57 mm cSVA, <-2.16^° MGS, >-30.8 mm C2-T3 SVA, and ≤-33.6^° TS-CL.

Conclusions

Certain ratios of correction of cervical parameters contribute to improving neck disability. Prioritizing these radiographic alignment parameters may help optimize patient-reported outcomes for patients undergoing CD surgery.