Accuracy, Reliability and Validity of a 3D Scanner for Assessing Torso Shape in Idiopathic Scoliosis.

By London Spine

Accuracy, Reliability and Validity of a 3D Scanner for Assessing Torso Shape in Idiopathic Scoliosis.

Spine (Phila Pa 1976). 2011 Oct 24;

Authors: Gorton GE, Young ML, Masso PD

Abstract
Study Design. Prospective cohort with concurrent controls.Objective. To establish accuracy, reliability and validity of the Vitronic 3D Body Scanner for evaluation of torso asymmetry in patients with idiopathic scoliosis.Summary of Background Data. Improved appearance is an important expectation of treatment for patients with scoliosis and their parents. Despite being the gold standard for quantifying outcomes, Cobb angles do not explain perception of appearance or quality of life. Surface topography is an attractive noninvasive alternative to radiography, but has not been studied in the context of patient-centered outcomes.Methods. Thirty-six adolescents with idiopathic scoliosis undergoing surgical correction had pre and postoperative radiographs and evaluation of standing posture, torso surface shape, and responses to the SRS-22 and Spinal Appearance Questionnaire. Twenty-one adolescents without scoliosis were evaluated for comparison. Scanner accuracy was assessed by scanning an object of known dimensions. Within session reliability of body shape measures constructed from scan data was assessed. Discriminant validity was assessed by examining pre to postoperative differences. Concurrent validity was examined through correlations of scan measures with radiographs, optoelectronic measures of posture, and self-report responses to the SRS-22 and SAQ.Results. Scan system measurement error was 1.74±1.56 mm. Within session reliability was excellent for the control (ICC = 0.83) and scoliosis (ICC = 0.94) groups. Medial/lateral torso shift, rotation and right/left asymmetry differed significantly among the preoperative, postoperative and control groups (ANOVA, p<0.05).. Torso asymmetry measures correlated with radiographic measures (r = 0.43-0.51), optoelectronic measures of posture and symmetry (r = 0.33-0.75), and appearance and quality of life domains of the SRS-22 (r = 0.35-0.64) and the SAQ (r = 0.48-0.67).Conclusions. The Vitronic 3D Body Scanner has sufficient accuracy, reliability and validity to monitor torso asymmetry due to scoliosis. Scan-based measures differentiate between normal and pathologic and between preoperative and postoperative body shape and show good correlation with measures of appearance and quality of life.

PMID: 22020589 [PubMed – as supplied by publisher]