Predictors of Superior Recovery Kinetics in Adult Cervical Deformity Correction: An Analysis Using a Novel Area Under the Curve Methodology.

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Spine (Phila Pa 1976)


washington; seattle; swedish neuro


STUDY DESIGN: Retrospective review of a prospective database.

OBJECTIVE: Identify demographic, surgical, and radiographic factors that predict superior recovery kinetics following CD corrective surgery.

SUMMARY OF BACKGROUND DATA: Analyses of cervical deformity (CD) corrective surgery use area-under-the-curve (AUC) to assess health-related quality of life (HRQL) metrics throughout recovery.

METHODS: Outcome Measures: Baseline (BL) to 1-Year (1Y) HRQL (Neck Disability Index [NDI]). CD criteria: C2-7 Cobb angle>10°, coronal Cobb angle>10°, cSVA>4 cm TS-CL>10°, or CBVA>25°. AUC normalization divided BL and postoperative outcomes by BL. Normalized scores(y-axis) were plotted against follow-up(x-axis). AUC was calculated and divided by cumulative follow-up length to determine overall, time-adjusted recovery (Integrated Health State [IHS]). IHS NDI was stratified by quartile, uppermost 25% being 'Superior' Recovery Kinetics (SRK) vs. 'Normal' Recovery Kinetics (NRK). BL demographic, clinical, and surgical information predicted SRK using generalized linear modeling.

RESULTS: 98 patients included (62 ± 10yrs, 28 ± 6 kg/m2, 65%F, CCI:0.95), 6% smokers, 31% smoking history. Surgical approach: combined (33%), posterior (49%), anterior (18%). Posterior levels fused: 8.7, anterior: 3.6, EBL: 915.9ccs, operative time: 495 min. Ames BL classification: cSVA (53.2% minor deformity, 46.8% moderate), TS-CL (9.8% minor, 4.3% moderate, 85.9% marked), horizontal gaze (27.4% minor, 46.6% moderate, 26% marked). Relative to BL NDI (Mean: 47), normalized NDI decreased at 3-months (0.9 ± 0.5, p = 0.260) and 1Y (0.78 ± 0.41, p < 0.001). NDI IHS correlated with age (p = 0.011), gender (p = 0.042), anterior approach (p = 0.042), posterior approach(p = 0.042). Greater BL PT (SRK:25.6°, NRK:17°, p = 0.002), PI-LL (SRK:8.4°, NRK:-2.8°, p = 0.009), and anterior approach (SRK:34.8%, NRK:13.3%; p = 0.020) correlated with SRK. 69.4% met MCID for NDI(

CONCLUSIONS: Superior recovery kinetics following cervical deformity surgery was predicted with high accuracy using baseline patient reported (VAS EQ5D, swallow sleep, mJOA) and radiographic factors (PT, TK, T10-L2, T12-S1, L1-S1). Awareness of these factors can improve decision-making and reduce postoperative neck disability.Level of Evidence: 3.

Clinical Institute

Neurosciences (Brain & Spine)

Clinical Institute

Orthopedics & Sports Medicine