Examination of the back using the Bunnell scoliometer in a Belgian school population around puberty

The present study was designed to determine whether quantified clinical measurement of the back would provide arguments supporting a biomechanical cause of adolescent idiopathic scoliosis (AIS). Two hundred ninety-two healthy girls (9 to 16 years) and 191 healthy boys (11 to 18 years) were examined clinically with the use of the Bunnell scoliometer. The inter- and intraobserver measurement error was determined. The accuracy of the Bunnell scoliometer as a biomorphological measurement method is good (variation coefficient +/- 10%). The measurement error is not influenced by the site of the rib hump or the type of scoliosis, but by the magnitude of the deformity to be measured. The present study confirms that the threshold for differentiating a physiological from a pathological gibbosity is 5 degrees C, as advanced by Bunnell (1984). The Bunnell measurement shows no statistically significant differences between boys and girls, although the standard deviation of the measurement in the declive segment is larger in girls. In all spinal segments measured, the scoliometer values show the same evolution in the boys and girls of the various age groups. Although the larger standard deviation in the declive segment in girls favors the existence of a physiological scoliosis, the present study shows no evolution in the various spinal segments for the age groups studied, and therefore does not substantiate the biomechanical etiopathogenic theories for the development of AIS.