Multicenter database review of consecutive adult spinal deformity (ASD) patients.
The aim of this study was to identify associations between changes in spinopelvic parameters and cervical alignment after thoracolumbar arthrodesis for ASD.
Reciprocal cervical changes occur after instrumented thoracic spinal arthrodesis. The timing and relationship of these changes to sagittal alignment and upper instrumented vertebra (UIV) selection are unknown.
In 171 ASD patients treated with thoracolumbar arthrodesis from 2008 to 2012, we assessed changes from baseline to 6-week, 1-year, and 2-year follow-up in C2-C7 sagittal vertical axis (SVA), T1 slope, and C2-C7 lordosis. We used multivariate models to analyze associations between these parameters and UIV selection (T9 or distal vs. proximal to T9) and changes at each time point in thoracic kyphosis (TK), lumbar lordosis (LL), C7-S1 SVA, pelvic incidence, pelvic tilt, and sacral slope.
Two-year changes in C2-C7 SVA and T1 slope were significantly associated with baseline to 6-week changes in TK and LL and with UIV selection. Baseline to 2-year changes in C2-C7 lordosis were associated with baseline to 6-week changes in C7-S1 SVA (P = 0.004). Most changes in C2-C7 SVA occurred during the first 6 weeks postoperatively (mean 6-week change in C2-C7 SVA: 2.7 cm, 95% confidence interval [CI]: 0.7–4.7 cm; mean 2-year change in SVA: 2.3 cm, 95% CI: −0.1 to 4.6 cm). At 2 years, on average, there was decrease in C2-C7 lordosis, most of which occurred during the first 6 weeks postoperatively (mean 6-week change: −3.2°, 95% CI: −4.8° to −1.2°; mean 2-year change: –1.3°, 95% CI: − 3.2° to 0.5°).
After thoracolumbar arthrodesis, reciprocal changes in cervical alignment are associated with postoperative changes in TK, LL, and C7-S1 SVA and with UIV selection. The largest changes occur during the first 6 weeks and persist during 2-year follow-up.
Level of Evidence: 3
In patients who undergo thoracolumbar arthrodesis for adult spinal deformity, changes in cervical sagittal radiographic parameters are associated with thoracolumbar radiographic changes and upper instrumented vertebra selection.
∗The Johns Hopkins University School of Medicine, Baltimore, MD
†University of California Davis, Sacramento, CA
‡Hospital for Special Surgery, New York, NY
§Washington University, St. Louis, MO
¶San Diego Center for Spinal Disorders, San Diego, CA
||NYU Hospital for Joint Diseases, New York, NY
∗∗Rocky Mountain Hospital for Children, Denver, CO
††University of Pittsburgh, Pittsburgh, PA
‡‡University of California San Diego, San Diego, CA
§§University of California San Francisco, San Francisco, CA.
Address correspondence and reprint requests to Brian J. Neuman, MD, Johns Hopkins University, 601 N Caroline St, JHOC 5241, Baltimore, MD 21287; E-mail: firstname.lastname@example.org
Received 11 February, 2019
Revised 4 April, 2019
Accepted 5 June, 2019
The manuscript submitted does not contain information about medical device(s)/drug(s).
The International Spine Study Group received financial support for the research, authorship, and/or publication of this article, in the form of funding form DePuy-Synthes Spine, K2 M, NuVasive, Orthofix, and Biomet.
Relevant financial activities outside the submitted work: board membership, consultancy, grants, royalties, payment for lecture, stocks.