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  • A Novel Score Predicting Spine Sagittal Imbalance Based On a Lateral Cervical Plain Radiograph

    Final Number:

    Ezequiel Goldschmidt MD PhD; Federico Angriman; Bruno Ferreyro; Peter C. Gerszten MD MPH FACS; Adam S. Kanter MD; David O. Okonkwo MD, PhD; Peter G Passias MD; Justin K. Scheer; Themistocles Protopsaltis MD; Virginie Lafage PhD; Renaud Lafage; Frank Schwab MD, PhD; Shay Bess MD; Christopher P. Ames MD; D. Kojo Hamilton MD; International Spine Study Group

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2016 Annual Meeting

    Introduction: Sagittal imbalance is recognized as a significant variable that contributes to spinal deformity. Clinical outcomes after spine surgery are known to correlate with sagittal balance, which is traditionally measured by the C7-S1 plumb line as demonstrated on a 36-inch long-cassette film. Abnormal positive alignment induces compensatory changes within the cervical spine, including increased cervical lordosis and T1 slope. Patients presenting clinically with cervical pathology are not routinely assessed with long-cassette films. A validated tool that could determine the likelihood of overall spine malalignment using cervical radiographs alone would be of significant clinical value.

    Methods: A retrospective review of 930 patients that were part of a prospectively collected, multicenter adult spinal deformity database was performed. The score was developed by a multivariable logistic regression model to predict a C7 plumb line greater than +50 mm. Variables including demographics, cervical lordosis, and T1 slope were analyzed. Patients were randomized in a 2:1 fashion into either a derivation or a validation cohort.

    Results: Of the 930 patients, 384 (41.3%) had a positive sagittal balance. The final score for predicting SB greater than +50mm included: BMI >25 (1 point), age >55 years (2 points), and T1 slope >27o (2 points). A score = 4 had a specificity of 81.8% (CI95% 77.7 - 85.5%) and a sensitivity of 61.0% (CI 95% 54.6 - 67.0%). The ROC area under the curve was 0.82 (CI95% 0.78-0.85) and 0.81 (CI95% 0.76-0.86) in the derivation and validation cohorts, respectively.

    Conclusions: This large multicenter study internally validated a score to assess sagittal balance based upon cervical radiographs, BMI, and age. The preoperative awareness of abnormal sagittal balance in patients with cervical pathology might change surgical treatment and clinical outcomes. Patients with high scores would benefit from long-cassette film evaluation.

    Patient Care: The score described in this paper can be used to select patients with cervical disease that are at risk of having a pathological positive malalignment. Ordering a 36-inch long-cassette film in those patients can aid in surgical planning, defining risks and predict outcomes after surgery.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of sagittal balance and its relation to clinical outcomes after surgery 2) Discuss, in small groups, how cervical parameters correlate with the C7-S1 plumb line 3) Discuss the clinical value of a score that can predict sagittal imbalance from a cervical radiograph and it clinical use

    References: Tomé-Bermejo F, Morales-Valencia JA, Moreno-Pérez J, Marfil-Pérez J, Díaz-Dominguez E, Piñera AR, Alvarez L. Long-term Changes in Sagittal Alignment and its Clinical Implications After Cervical Interbody Fusion Cage Subsidence for Degenerative Cervical Disc Disease. A Prospective Study with Standalone Lordotic Tantalum Cages. J Spinal Disord Tech. 2015 May 25. [Epub ahead of print] PubMed PMID: 26016542. Protopsaltis TS, Scheer JK, Terran JS, Smith JS, Hamilton DK, Kim HJ, Mundis GM Jr, Hart RA, McCarthy IM, Klineberg E, et al. How the neck affects the back: changes in regional cervical sagittal alignment correlate to HRQOL improvement in adult thoracolumbar deformity patients at 2-year follow-up. J Neurosurg Spine. 2015 Aug;23(2):153-8. doi: 10.3171/2014.11.SPINE1441. Epub 2015 May 15. PubMed PMID: 25978077. Núñez-Pereira S, Hitzl W, Bullmann V, Meier O, Koller H. Sagittal balance of the cervical spine: an analysis of occipitocervical and spinopelvic interdependence, with C-7 slope as a marker of cervical and spinopelvic alignment. J Neurosurg Spine. 2015 Jul;23(1):16-23. doi: 10.3171/2014.11.SPINE14368. Epub 2015 Apr 24. PubMed PMID: 25909271 Ames CP, Smith JS, Scheer JK, Bess S, Bederman SS, Deviren V, Lafage V, Schwab F, Shaffrey CI. Impact of spinopelvic alignment on decision making in deformity surgery in adults: A review. J Neurosurg Spine. 2012 Jun;16(6):547-64. doi: 10.3171/2012.2.SPINE11320. Epub 2012 Mar 23. Review. PubMed PMID: 22443546. Sugrue PA, McClendon J Jr, Smith TR, Halpin RJ, Nasr FF, O'Shaughnessy BA, Koski TR. Redefining global spinal balance: normative values of cranial center of mass from a prospective cohort of asymptomatic individuals. Spine (Phila Pa 1976). 2013 Mar 15;38(6):484-9. doi: 10.1097/BRS.0b013e318273a1c0. PubMed PMID: 22986836.

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