, Volume 23, Issue 6, pp 1244-1250,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 01 Apr 2014

Calculation of corrected body height in idiopathic scoliosis: comparison of four methods

Abstract

Purpose

The aim of the study was to analyze four radiographic methods of calculating the loss of body height associated with scoliosis.

Methods

Thirty patients with right thoracic idiopathic scoliosis were examined with standing postero-anterior radiographs. Cobb angles of the upper thoracic, main thoracic and lumbar curves were measured. The loss of body height due to scoliosis was measured directly on the radiographs and then calculated using the methods of Bjure, Kono, Stokes and Ylikoski, respectively. The reproducibility of calculations was tested. Detailed analysis of two patients with similar Cobb angle but different trunk height was performed.

Results

The mean Cobb angle of the main thoracic curve was 46° (21°–74°). The mean loss of body height was 23 mm (11–43 mm) calculated by method of Bjure, 7 mm (−24 to 46 mm) by Kono, 20 mm (5–47 mm) by Stokes, 14 mm (3–36 mm) by Ylikoski, versus 18 mm (3–50 mm) measured directly on radiographs. The overall difference between the loss of body heights was significant (p < 0.0001), with significant differences in pairs for: Bjure versus Kono (p < 0.0001), Stokes versus Kono (p = 0.0002), Kono versus measured (p = 0.0061) and Bjure versus Ylikoski (p = 0.0386). Strong linear correlation between the methods was found (r ≥ 0.92; p < 0.0001). High reproducibility of height loss calculations was noticed. The two patients with similar Cobb angle and different trunk height revealed similar height loss calculated, while different loss measured on radiographs.

Conclusions

There existed no overall agreement between the four methods of calculation of the loss of body height associated with scoliosis. Calculations based on the Cobb angle produced inaccuracy and could be supplemented with data considering trunk size.