What are normal radiographic spine and shoulder balance parameters among adolescent patients?

Document Type

Article

Publication Date

2-24-2020

Publication Title

Spine Deformity

Abstract

Study design: Retrospective. Objectives: To define normal values and distributions for sagittal, coronal, and shoulder balance among healthy adolescents, both for traditional radiographs and biplanar radiography. Summary of background data: Our understanding of spine balance, especially in the sagittal plane, has expanded rapidly in recent years. Additionally, there has been growing use of simultaneous biplanar radiography which requires slightly different patient positioning. However, the normal ranges of several commonly used parameters have not yet been defined, either in traditional or biplanar radiography. Methods: Radiographs were retrospectively reviewed of 273 patients aged 10–18 years seen in spine clinics at two high-volume centers and not diagnosed with any spine pathology. One center utilized traditional radiography and the other biplanar radiography. Coronal, sagittal, and shoulder balance were measured for each patient. Intra-observer reliability and normal values with distributions were reported for each parameter. Results: Intra-observer reliability was excellent (intra-class correlation coefficients ≥ 0.98). Each parameter was normally distributed at each institution based on Kolmogorov–Smirnov testing. Sagittal balance was more negative at the institution using traditional radiographs (− 3.4 ± 4.2 vs. 0.3 ± 2.2, p < 0.001). Coronal balance was statistically, but not clinically, significantly more negative at this institution (− 0.6 ± 1.4 vs. − 0.2 ± 1.0, p = 0.007). Shoulder balance was not different between institutions. The “normal” ranges (mean ± 2 standard deviations, i.e., expected to include 95% of patients) were − 2.8 to 2.0 cm for coronal balance, − 9.0 to 6.1 cm for sagittal balance, and − 1.5–2.4 cm for shoulder balance. Conclusions: In adolescents without known spine pathology, the mean coronal, sagittal, and shoulder balance is near neutral, but each parameter varies over a large range; so the average patient deviates from neutral by 1.0 ± 0.7 cm, 3.1 ± 2.6 cm, and 0.9 ± 0.7 cm, respectively. The most important difference between biplanar and traditional radiographs was a significantly more negative sagittal balance in the biplanar group which may be attributable to arm positioning. Level of evidence: Level III.

First Page

621

Last Page

627

PubMed ID

32096131

Volume

8

Issue

4

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