Prioritization of Realignment Associated With Superior Clinical Outcomes for Cervical Deformity Patients

Abstract

Objective: To prioritize the cervical parameter targets for alignment.Methods: Included: cervical deformity (CD) patients (C2–7 Cobb angle > 10°, cervical lordosis > 10°, cervical sagittal vertical axis [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 cervical lordosis (TS–CL) ( < 15°) were excluded. Patients assessed: meeting minimum clinically important differences (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 cutoffs for differences associated with meeting NDI MCID at 1Y.Results: Seventy-seven CD patients (mean age, 62.1 years; 64% female; body mass index, 28.8 kg/m2). Forty-one point six percent of patients met MCID for NDI. A backwards linear regression model including radiographic differences as predictors from BL to 1Y for meeting MCID for NDI demonstrated an R2 of 0.820 (p = 0.032) included TS–CL, cSVA, McGregor’s slope (MGS), C2 sacral slope, C2–T3 angle, C2–T3 SVA, cervical lordosis. 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 2 groups (p > 0.050). Decision tree analysis determined cutoffs for radiographic change, prioritizing in the following order: ≥ 42.5° C2–T3 angle, > 35.4° cervical lordosis, < -31.76° C2 slope, < -11.57-mm cSVA, < -2.16° MGS, > -30.8-mm C2–T3 SVA, and ≤ -33.6° TS–CL.Conclusion: 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.

Odontoid Incidence: A Novel Cervical Parameter Influencing Cervical Alignment From Top to Bottom

“…29,30 As with PI and LL, the greater the T1S, the larger CL is necessary in order to balance the head for harmonious alignment. 17,23,24,31 Therefore, T1S-CL describes the compensation between the cervical alignment and upper thoracic alignment. 19 If there is insufficient CL to match a given T1S in a patient, C2 will tilt forward to increase C2S.…”

“…19 Additionally, C2S has been shown to correlate with patient-reported outcomes and with T1S-CL, C0-2 angle, cSVA, CL, and T1S. 19,31 Cervical alignment is influenced by global sagittal alignment through compensatory mechanisms. [1][2][3][4][5]28 But what limits the alignment in the rostral end?…”

“…Nevertheless, the T1S-CL has been proposed as a parameter analogous to PI–LL to better define cervical alignment [ 29 , 30 ]. As with PI and LL, the greater the T1S, the larger CL is necessary in order to balance the head for harmonious alignment [ 17 , 23 , 24 , 31 ]. Therefore, T1S–CL describes the compensation between the cervical alignment and upper thoracic alignment [ 19 ].…”

“…If there is insufficient CL to match a given T1S in a patient, C2 will tilt forward to increase C2S [ 19 ]. Additionally, C2S has been shown to correlate with patient-reported outcomes and with T1S–CL, C0–2 angle, cSVA, CL, and T1S [ 19 , 31 ].…”

Clinical Impact and Correlations of Odontoid Parameters Following Multilevel Posterior Cervical Fusion Surgery

“…4 Analogous to the aforementioned PI-LL, a greater mismatch in T1 slope (T1S) minus cervical lordosis (CL; T1S-CL) is associated with a greater degree of cervical malalignment and worse health-related quality of life (HRQoL) outcomes. [5][6][7][8][9] To simplify the assessment of cervical malalignment, a novel parameter-C2 slope (C2S), which is mathematically approxi-…”