Photogrammetry: an accurate and reliable tool to detect thoracic musculoskeletal abnormalities in preterm infants

Abstract Objective To analyse the accuracy and reproducibility of photogrammetry in detecting thoracic abnormalities in infants born prematurely. Design Cross-sectional study. Setting The Premature Clinic at the Federal University of São Paolo. Participants Fifty-eight infants born prematurely in their first year of life. Outcome measures Measurement of the manubrium/acromion/trapezius angle (degrees) and the deepest thoracic retraction (cm). Digitised photographs were analysed by two blinded physiotherapists using a computer program (SAPO; http://SAPO.incubadora.fapesp.br ) to detect shoulder elevation and thoracic retraction. Physical examinations performed independently by two physiotherapists were used to assess the accuracy of the new tool. Results Thoracic alterations were detected in 39 (67%) and in 40 (69%) infants by Physiotherapists 1 and 2, respectively (kappa coefficient = 0.80). Using a receiver operating characteristic curve, measurement of the manubrium/acromion/trapezius angle and the deepest thoracic retraction indicated accuracy of 0.79 and 0.91, respectively. For measurement of the manubrium/acromion/trapezius angle, the Bland and Altman limits of agreement were −6.22 to 7.22° [mean difference ( d ) = 0.5] for repeated measures by one physiotherapist, and −5.29 to 5.79° ( d = 0.75) between two physiotherapists. For thoracic retraction, the intra-rater limits of agreement were −0.14 to 0.18 cm ( d = 0.02) and the inter-rater limits of agreement were −0.20 to −0.17 cm ( d = 0.02). Conclusion SAPO provided an accurate and reliable tool for the detection of thoracic abnormalities in preterm infants.