Use of the iPhone for Cobb angle measurement in scoliosis

Shaw, Matthew J., Adam, Clayton J., Izatt, Maree T., Licina, Paul, & Askin, Geoffrey N. (2011) Use of the iPhone for Cobb angle measurement in scoliosis. European Spine Journal, 21(6), pp. 1062-1068.

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Purpose: The Cobb technique is the universally accepted method for measuring the severity of spinal deformities. Traditionally, Cobb angles have been measured using protractor and pencil on hardcopy radiographic films. The new generation of mobile phones make accurate angle measurement possible using an integrated accelerometer, providing a potentially useful clinical tool for assessing Cobb angles. The purpose of this study was to compare Cobb angle measurements performed using an Apple iPhone and traditional protractor in a series of twenty Adolescent Idiopathic Scoliosis patients.

Methods: Seven observers measured major Cobb angles on twenty pre-operative postero-anterior radiographs of Adolescent Idiopathic Scoliosis patients with both a standard protractor and using an Apple iPhone. Five of the observers repeated the measurements at least a week after the original measurements.

Results: The mean absolute difference between pairs of iPhone/protractor measurements was 2.1°, with a small (1°) bias toward lower Cobb angles with the iPhone. 95% confidence intervals for intra-observer variability were ±3.3° for the protractor and ±3.9° for the iPhone. 95% confidence intervals for inter-observer variability were ±8.3° for the iPhone and ±7.1° for the protractor. Both of these confidence intervals were within the range of previously published Cobb measurement studies.

Conclusions: We conclude that the iPhone is an equivalent Cobb measurement tool to the manual protractor, and measurement times are about 15% less. The widespread availability of inclinometer-equipped mobile phones and the ability to store measurements in later versions of the angle measurement software may make these new technologies attractive for clinical measurement applications.

Impact and interest:

39 citations in Scopus
27 citations in Web of Science®
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ID Code: 48852
Item Type: Journal Article
Refereed: Yes
Additional Information: Springer Online First publication
Keywords: scoliosis, Cobb angle, iPhone, smartphone, measurement variability, Apple iPhone, spinal deformity
DOI: 10.1007/s00586-011-2059-0
ISSN: 0940-6719
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > BIOMEDICAL ENGINEERING (090300) > Biomechanical Engineering (090302)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > CLINICAL SCIENCES (110300) > Orthopaedics (110314)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2011 Springer
Copyright Statement: The original publication is available at SpringerLink
Deposited On: 26 Feb 2012 22:58
Last Modified: 24 Aug 2014 02:37

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