Do the newly proposed realignment targets bridge the gap between radiographic and clinical success in adult cervical deformity corrective surgery.

HYPOTHESIS

The myelopathy-based cervical deformity (CD) thresholds will associate with patient-reported outcomes and complications.

MATERIALS AND METHODS

This study include CD patients (C2-C7 Cobb > 10°, CL > 10°, cervical sagittal vertical axis > 4 cm, or CBVA > 25°) with BL and 1-year (1Y) data. Modifiers assessed low (L), moderate (M), and severe (S) deformity: CL (L: >3°; M:-21° to 3°; S: <‒21°), TS-CL (L: <26°; M: 26° to 45°; S: >45°), C2-T3 angle (L: >‒25°; M:-35° to-25°; S: <‒35°), C2 slope (L: <33°; M: 33° to 49°; S: >49°), MGS (L: >‒9° and < 0°; M: ‒12° to ‒9° or 0° to 19°; S: < ‒12° or > 19°), and frailty (L: <0.18; M: 0.18-0.27, S: >0.27). Means comparison and ANOVA assessed outcomes in the severity groups at BL at 1Y. Correlations found between modifiers assessed the internal relationship.

RESULTS

One hundred and four patients were included in the study (57.1 years, 50%, 29.3 kg/m). Baseline S TS-CL, C2-T3, and C2S modifiers were associated with increased reoperations ( < 0.01), while S MGS, CL, and C2-T3 had increased estimated blood lost (>1000ccs, < 0.001). S MGS and C2-T3 had more postop DJK (60%, = 0.018). Improvement in TS-CL, C2S, C2-T3, and CL patients had better numeric rating scale (NRS) back (<5) and EuroQOL 5-Dimension questionnaire (EQ5D) at 1 year ( < 0.05). Improving the modifiers correlated strongly with each other (0.213-0.785, < 0.001). Worsened TS-CL had increased NRS back scores at 1 year (9, = 0.042). Worsened CL had increased 1-year modified Japanese Orthopedic Association (mJOA) (7, = 0.001). Worsened C2-T3 had worse NRS neck scores at 1 year ( = 0.048). Improvement in all six modifiers (8.7%) had significantly better health-related quality of life (HRQL) scores at follow-up (EQ5D, NRS, and Neck Disability Index).

CONCLUSIONS

Newly proposed CD modifiers based on mJOA were closely associated with outcomes. Improvement and deterioration in the modifiers significantly impacted the HRQL.