Prioritization of realignment associated with superior clinical outcomes for surgical cervical deformity patients

Katherine E Pierce; Peter Gust Passias; Avery E Brown; Cole A Bortz; Haddy Alas; Renaud Lafage; Oscar Krol; Dean Chou; Douglas C Burton; Breton Line; Eric Klineberg; Robert Hart; Jeffrey Gum; Alan Daniels; Kojo Hamilton; Shay Bess; Themistocles Protopsaltis; Christopher Shaffrey; Frank A Schwab; Justin S Smith; Virginie Lafage; Christopher Ames; International Spine Study Group

doi:10.4103/jcvjs.jcvjs_26_21

Prioritization of realignment associated with superior clinical outcomes for surgical cervical deformity patients

J Craniovertebr Junction Spine. 2021 Jul-Sep;12(3):311-317. doi: 10.4103/jcvjs.jcvjs_26_21. Epub 2021 Sep 8.

Authors

Katherine E Pierce^{1

2}, Peter Gust Passias^{1

2}, Avery E Brown^{1

2}, Cole A Bortz^{1

2}, Haddy Alas^{1

2}, Renaud Lafage³, Oscar Krol^{1

2}, Dean Chou⁴, Douglas C Burton⁵, Breton Line⁶, Eric Klineberg⁷, Robert Hart⁸, Jeffrey Gum⁹, Alan Daniels¹⁰, Kojo Hamilton¹¹, Shay Bess¹², Themistocles Protopsaltis¹³, Christopher Shaffrey^{14

15}, Frank A Schwab³, Justin S Smith¹⁶, Virginie Lafage³, Christopher Ames⁴; International Spine Study Group

Affiliations

¹ Department of Orthopaedic, New York Spine Institute, NYU Langone Orthopedic Hospital, New York, NY, USA.
² Departments of Neurologic Surgery, New York Spine Institute, NYU Langone Orthopedic Hospital, New York, NY, USA.
³ Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA.
⁴ Department of Neurological Surgery, University of California, San Francisco, CA, USA.
⁵ Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, KS, USA.
⁶ Department of Spine Surgery, Denver International Spine Center, Presbyterian St. Luke's/Rocky Mountain Hospital for Children, Denver, CO, USA.
⁷ Department of Orthopaedic Surgery, University of California, Davis, CA, USA.
⁸ Department of Orthopaedic Surgery, Swedish Neuroscience Institute, Seattle, WA, USA.
⁹ Norton Leatherman Spine Center, Louisville, KY, USA.
¹⁰ Department of Orthopaedic Surgery, Warren Alpert School of Medicine, Brown University, Providence, RI, USA.
¹¹ Department of Neurological Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
¹² Department of Spine Surgery, Denver International Spine Clinic, Presbyterian St. Luke's/Rocky Mountain Hospital for Children, Denver, Colorado, USA.
¹³ Department of Orthopaedics, NYU Langone Orthopedic Hospital, New York, NY, USA.
¹⁴ Department of Neurosurgery, Duke University Medical Center, Durham, NC, USA.
¹⁵ Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
¹⁶ Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA.

Abstract

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.

Keywords: Cervical deformity; prioritization; realignment.