The diagnostic accuracy of community spine radiology for adolescent idiopathic scoliosis brace candidates

Abstract

Purpose: The study aims to establish the diagnostic accuracy of community spine x-rays for brace candidates. Methods: A review of adolescent idiopathic scoliosis patients seen for initial visit at a tertiary care pediatric hospital was conducted (n = 170). The index test was the pre-referral community spine x-ray interpreted by a community radiologist. Measures of diagnostic accuracy for the index test were determined against the reference standard if images were obtained within 90 days (n = 111). The reference standard was the 3-foot standing EOS spine x-ray evaluated by spine specialists. Diagnostic criterion for a brace candidate was dichotomized by Cobb angle range (25–40°) according to Scoliosis Research Society criteria. Risser stage was not included given significant missing data in index reports. To mitigate the uncertainty around true progression, sensitivity analyses were conducted on a sub-sample of data when index test was within 60 days of the reference standard (n = 67). Results: Accuracy of the community spine x-ray to detect a brace candidate was 65.8% (95% CI 56.2–74.5). Sensitivity of the index test was 65.4% with a false negative rate of 34.6%. Specificity was 66.1% with a false positive rate of 33.9%. Positive and negative predictive values were 63.0% and 68.4%, respectively. Of the total number of brace candidates (n = 52), 32.7% were missed because of underestimation in Cobb angle (95% CI 21.5–46.2). The proportion of missed brace candidates because of underestimation was unchanged with 60-day data (p = 0.37). Conclusions: Inaccuracies in community spine radiology may lead to missed opportunities for non-operative treatment.