General Session: Adult Spinal Deformity-2

Presented by: C. Jalai - View Audio/Video Presentation (Members Only)

Author(s):

P. Passias(1), C. Jalai(1), N. Worley(1), J. Scheer(2), A. Soroceanu(1), T. Protopsaltis(1), E. Klineberg(3), D. Sciubba(4), B. Neuman(5), H.J. Kim(6), D.K. Hamilton(7), J. Smith(8), V. Lafage(6), C. Ames(9), International Spine Study Group

(1) NYU Hospital for Joint Diseases, Department of Orthopaedic Surgery, New York, NY, United States
(2) Northwestern University, Department of Neurosurgery, Chicago, IL, United States
(3) University of California, Davis, Department of Orthopaedic Surgery, Sacramento, CA, United States
(4) Johns Hopkins Hospital, Department of Neurosurgery, Baltimore, MD, United States
(5) Johns Hopkins Hospital, Department of Orthopaedics, Baltimore, MD, United States
(6) Hospital for Special Surgery, Department of Orthopaedics, New York, NY, United States
(7) University of Pittsburgh Medical Center, Department of Neurological Surgery, Pittsburg, PA, United States
(8) University of Virginia, Department of Neurosurgery, Charlottesville, VA, United States
(9) University of California, San Francisco, Department of Neurosurgery, San Francisco, CA, United States

Abstract

Object: Development of new-onset cervical deformity (CD) has been observed in adult thoracolumbar deformity patients undergoing surgical treatment. However, this issue may also be important in non-operative ASD patients, yet it remains to be fully investigated in this patient group.

Methods: Retrospective review of prospective data for ASD non-operative patients. Inclusion criteria was 1-, 2-, and 3-year follow-up for non-operative ASD patients with complete demographic data. CD was defined as ≥2 of the following: T1S-CL>20°, C2-C7 SVA>40mm, or C2-C7 kyphosis>10°. Cervical alignment was defined as ≥2 of the following: T1S-CL< 20°, C2-C7 SVA≤40mm, or C2-C7 kyphosis≤0°. New onset CD patients were defined as cervically aligned at baseline. Univariate and multivariate analyses determined predictors of new onset CD at 3 time points and impact on patient-reported outcomes.

Results: 89 non-operative ASD patients with complete follow-up (mean age: 52.3 years, mean BMI: 52.8 kg/m2, 87.6% female). The baseline rate of CD of the total cohort was 38.2% (34 patients). 51.7% of patients met T1S-CL threshold, 38.2% met SVA, and 59.6% met cervical lordosis. Of the total cohort, 52.8% (47 patients) were cervically aligned at baseline. Of these patients, the incidence of new onset non-operative CD was 38.8% at 1-year, 46.8% at 2-years, 21.3% 3-years. The comparison of the sagittal profiles between patients who remained well aligned and those who developed new CD at each time point revealed no differences in global sagittal spino-pelvic parameters (thoracic kyphosis, pelvic tilt, global alignment) at any follow-up time point (p>0.05); new onset non-operative CD was only due to the cervical deformity parameters considered. Increased baseline C2 sacral slope positively predicted new onset CD in non-operative patients at 2-years (OR 1.17, p=0.001). Increased pelvic tilt (PT) at baseline was identified as significantly associated with increased risk of developing de novo non-op CD at 2 (OR: 1.11, p=0.008) and 3 (OR: 1.19, p=0.035) year follow-up. Mutlivariate measures mixed models revealed that at 1- and 20year follow-up for non-op patients, CD onset did not impact HRQoL´s in all considered categories (p>0.05). But the SRS Mental Component Score for new onset CD patients at 3-years was higher compared to aligned patients (p=0.046). At 2-year follow-up, SF-36 MCS BL-2year difference was significantly greater in new onset CD patients (3.95 vs. -2.38, p=0.025).

Conclusions: The overall new onset CD rate for non-operative patients was 35.6% over a 3 years follow-up. Baseline C2 slope severity and pelvic tilt were associated with new onset non-operative CD, and no differences in sagittal spino-pelvic parameters were correlated with new CD at any of the time points. Of the HRQL score differences considered, the mean baseline-3year SF-36 Mental Component Score among non-operative new CD patients was slightly decreased compared to aligned patients, indicating a potential clinical impact associated with deformity onset in patients receiving non-operative treatment.