Clinical study Analysis of accuracy of kyphotic angle measurement for vertebral osteoporotic compression fractures Sang Won Lee a , Jae Taek Hong a, * , Byung Chul Son a , Jae Hoon Sung a , Il Sub Kim a , Chun Kun Park b a Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea b Department of Neurosurgery, Kangnam St. Marys’ Hospital, The Catholic University of Korea, Seoul, Korea Received 6 March 2006; accepted 6 August 2006 Abstract A reliable and reproducible measurement technique for the sagittal contour in vertebral fractures is paramount to clinical decision- making. This study was designed to determine the most reliable measurement technique in osteoporotic vertebral compression fracture. Fifteen lateral radiographs of thoracic and lumbar fractures were selected and measured on two separate occasions by three spine sur- geons using six different measurement techniques (centroid, Harrison posterior tangent method and 4 different types of modified Cobb method). The radiograph quality was assessed and the center beam location was determined. The inter- and intraobserver variance of the Cobb method 4 and the Harrison posterior tangent method were significantly lower than for the other four methods. The intraobserver correlation coefficients were the most consistent using the Cobb method 4 (0.982), followed by the Harrison posterior tangent method (0.953) and Cobb method 1 (0.874). The intraobserver agreement (% of repeated measures within 5° of the original measurement) ranged from 42% to 98% for each technique for all three observers, with the Cobb method 4 showing the best agreement (97.8%) followed by the Harrison posterior tangent method (93.7%). The Cobb method 4 and Harrison posterior tangent method, when applied to measuring the kyphosis, were reliable and had a similar small error range. The Cobb method 4 showed the best overall reliability. The centroid method and the other Cobb methods using a fractured endplate did not produce an accurate result due to inter- and intraobserver differences in determining the baseline. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Osteoporosis; Vertebral compression fracture; Kyphotic angle; Modified Cobb method; Harrison posterior tangential method; Centroid method 1. Introduction Osteoporosis is a major health issue for the elderly, and the incidence of vertebral compression fracture-related se- quela is expected to increase as the general population ages. Therefore, osteoporotic compression fractures of the thora- columbar vertebrae are becoming an increasing part of the practice of all spine surgeons. 1–3 Having a reliable and reproducible measurement tech- nique is essential when making clinical decisions regarding the treatment of thoracolumbar spine deformities. 4,5 Because there are few reliability studies for measuring the thoracolumbar kyphosis in an osteoporotic vertebral compression fracture, 6 this study examined the reliability and clinical utility of kyphosis determination using six dif- ferent radiographic methods. The six methods for kyphotic angle measurement were compared statistically. 2. Materials and methods Fifteen lateral radiographs of thoracic and lumbar oste- oporotic vertebral compression fractures were selected and 0967-5868/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2006.08.005 * Corresponding author. Present address: 93-6 Chi-dong Paldal-ku Suwon 442-723 Korea. Tel.: +82 31 249 7190; fax: +82 31 245 5208. E-mail address: jatagi15@paran.com (J.T. Hong). www.elsevier.com/locate/jocn Journal of Clinical Neuroscience 14 (2007) 961–965