General Session: Adult Spinal Deformity

Presented by: L. Pimenta - View Audio/Video Presentation (Members Only)


L. Marchi(1), F. Fortti(1), R. Amaral(1), L. Oliveira(1), J. Nogueira-Neto(1), R. Jensen(1), L. Pimenta(1,2)

(1) Instituto de Patologia da Coluna, Sao Paulo, Brazil
(2) UCSD, Neurosurgery, San Diego, CA, United States


Objective: This work intent to evaluate the reliability and equivalency using the Cobb meter app in comparison to the manual measurement of sagittal alignment of the spine.

Methods: Transversal study, prospective, single-center, which were analyzed 20 panoramic X-rays films in lateral and neutral orthostatic position, in a blind and random fashion, with three independent examiners in three different timepoints. The parameters acquired were: pelvic incidence (PI), pelvic tilt (PT) and lumbar lordosis (LL). Statistical analysis were performed to measure the intraclass correlation (ICC) between the two measurement methods, besides measure the reliability inter and intra-evaluator.

Results: To reproducibility analysis, the ICC intra-evaluator, using the app, resulted in a Kappa (K) of 0.975 for pelvic incidence (PI) evaluation. To pelvic tilt (PT), the K value obtained was 0.981 and the measured K for lumbar lordosis (LL) analysis was 0.987. The inter-evaluator reproducibility evaluation, using the app, resulted in a K value of 0.917 for IP evaluation, 0.930 for VP and 0.951 for LL. For equivalency methods evaluation, comparing the app to the standard method of goniometer and dermatographic pencil, the K value found in PI measurement was 0.873, K of 0.939 for VP and 0.914 for LL. All values were significant (p< 0.001) against the null hypothesis.

Conclusion: This smartphone app is a valid and reliable instrument for angle measurement in sagittal alignment of the spine. Besides, the results show that its applicability is not inferior to the manual method with goniometer and dermatographic pencil.

Smartphone position for obtaining the parameters