Equivalent values between anterior vertebral height, wedge ratio, and wedge angle in osteoporotic vertebral fractures.

Abstract

Vertebral mobility (V-mobility) has been used to diagnose fresh osteoporotic vertebral fractures (OVFs), and determine or predict bone union by setting cutoff values for these purposes. V-mobility is defined as the difference in shape of vertebral bodies between lateral radiographs taken in weight-bearing and non-weight-bearing positions. The parameters for V-mobility have varied in previous reports among anterior vertebral height (Ha, mm), wedge ratio (WR, %), and wedge angle (WA, degrees). The present study aimed to clarify WR and WA equivalent to Ha of 1.0mm, and to compare the reported cutoff values for V-mobility presented as Ha, WR, or WA. Lateral radiographs of 446 normal vertebrae (grade 0) and 146 deformed vertebrae (grade 1-3) from T11 to L2 were obtained from 183 female patients aged > 60years. WR (%) values equivalent to Ha of 1.0mm were calculated by Ha (1.0mm)/Hp × 100 (Hp: posterior vertebral height). Corresponding WA values were calculated by trigonometric function using vertebral dimensions. The mean WR values equivalent to Ha of 1.0mm in the vertebrae from T11 to L2 were 3.2%, 3.2%, 3.5%, and 3.7% for grades 0, 1, 2, and 3, respectively, and the corresponding WA values were 1.6°, 1.6°, 1.5°, and 1.4°. The equivalent values for V-mobility presented as Ha, WR, and WA were obtained. The mean WR and WA values equivalent to Ha of 1.0mm in grade 1-3 vertebrae were 3.5% and 1.5°, respectively.