This study aimed to verify the accuracy of the DIERS Formetric Scan when assessing vertebral rotation of the apical vertebrae in Adolescent Idiopathic Scoliosis (A.I.S) patients, to determine whether the DIERS Formetric Scans can be used instead of or alongside radiographs when assessing A.I.S patients.

Both the radiographs and the DIERS Formetric Scans of 60 Preoperative A.I.S patients. All patients included in our study had predominant thoracic curves using the Lenke classification method, Cobb angle range 33° – 85°. Each radiograph was categorised into groups according to the severity of Nash-Moe rotation score of the apical vertebrae. Three groups were formed Nash-Moe +1 (20 patients), Nash-Moe +2 (27 patients), Nash-Moe +3 (13 patients). Each result was then compared to the maximal rotation analysed by the DIERS Formetric Scan, which took place on the same day as the radiographs. The results were then assessed using a Pearson Correlation Coefficient and a One-Way ANOVA with Post-Hoc Tukey HSD Analysis.

The Nash-Moe +1 Group scored a mean maximal rotation of 14.65° ±6.56 (11.82 – 17.48) (95% Confidence Interval), Nash-Moe +2 mean maximal rotation was 19.6° ±7.1 (16.92 – 22.28) and Nash-Moe +3 scored 21.53° ±8.9 (16.99 – 26.37). The Pearson Correlation Coefficient of this assessment was +0.342 (p value 0.07) demonstrating a weak positive correlation. The One-Way ANOVA analysis with Post-Hoc Tukey HSD analysis. The results of this analysis was an F value score of +4.115 (p Value 0.021) for the overall One-Way ANOVA test. The Post-Hoc Tukey HSD tests demonstrate that there is a statistical difference between Group 1 and Group 3 (p value 0.030) but there is no statistical difference between Group 1 and Group 2 (p value 0.068) as well as no statistical difference between Group 2 and Group 3 (p value 0.716).

DIERS Formetric Scan assessment of vertebral rotation shows a positive correlation with the Nash-Moe method. This allows us to rely on the Formetric scans and thus a possible reduction in radiographs when assessing A.I.S, this reduces the exposure to ionising radiation in A.I.S patients.