Introduction: Development of new-onset cervical deformity (CD) has been noted in adult thoracolumbar deformity patients. This study identifies predictors of new CD and determines impact on patient-reported outcomes in nonop patients.
Methods: 1, 2, and 3yr f/u was available for non-op ASD patients. CD was defined as =2 of the following: T1S-CL>20°, C2- C7 SVA>40mm, or C2-C7 kyphosis>10°. Cervical alignment was defined as =2 of the following: T1S-CL<20°, C2- C7 SVA=40mm, or C2-C7 kyphosis=0°. Univariate and multivariate analyses determined new CD predictors at 3 time points and impact on HRQOLs (ODI, PCS, MCS, all SRS).
Results: 89 non-op patients had complete follow-up (mean age: 52.3 yrs, 87.6% female). Pre-op rate of CD was 38.2%, with 51.7% of them meeting cSVA threshold, 38.2% T1S-CL, and 59.6% for CL. Incidence of new CD was 40.7%, 42.5%, 51.1% at 1, 2, and 3yrs, respectively, versus 60.9% at 3yrs post-op. The comparison of sagittal profiles between patients who remained well aligned and those who developed new CD revealed no differences in global sagittal spino-pelvic parameters (thoracic kyphosis, pelvic tilt, global alignment) at any follow-up time point (p>0.05); new CD was only due to CD parameters. Increased BL C2-slope positively predicted new CD in patients at 2yrs (OR 1.17, p=0.001). Both patients with and without new onset CD improved in MCS BL-3yr scores, but new CD improved slightly less (newCD mean: 0.28, noCD mean: 0.41, p=0.005).
Conclusions: Overall non-op new CD rate was 44.8%, similar to that of op patients (63%). BL C2 slope severity predicted new CD, and no differences in sagittal spino-pelvic parameters were associated with new CD at any time points. Of the HRQOL score differences considered, only the mean baseline-3yr SF-36 Mental Component Score among non-op new CD patients was slightly decreased compared to aligned patients, indicating potential clinical impact associated with deformity onset.
Patient Care: This study will help improve patient care by identifying important potential predictors of new onset cervical deformity in nonoperative patients and the potential clinical impact of this new deformity.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) further understand new onset CD in nonoperative patients, 2) identify increased baseline C2 slope as a predictor of new onset CD, 3) understand the potential impact of HRQOL associated with new onset CD.