Article

Adolescent idiopathic scoliosis (AIS) can require surgical procedures
that have major consequences. Coronal imbalance as assessed clinically using a
plumb line is a key criterion for selecting patients to surgery. Nevertheless,
the reference standard for assessing postural balance of the trunk is gravity
line localisation within a validated frame of reference.
Recent studies have
established that the gravity line can be localised after body contour
reconstruction from biplanar radiographs.
The objective of this study was to
validate a gravity line localisation method based on biplanar radiographs in a
population with AIS then to validate gravity line position versus plumb line
position. HYPOTHESIS: Plumb line and gravity line assessments of coronal balance
correlate with each other. MATERIAL AND METHODS: A gravity line localisation
method based on biplanar radiography was validated in 14 patients with AIS versus
force platform as the method of reference. Normal plumb line and gravity line
positions were determined in 27 asymptomatic adolescents using biplanar
radiography. The results of the two methods were then compared in 53 patients
with AIS. RESULTS: The reliability of gravity line localisation in the coronal
plane based on biplanar radiography was 2.4mm (95% confidence interval). The
distance between the gravity line and the middle of the line connecting the
centres of the two femoral heads (HA) showed a strongly significant association
with plumb line position computed as the distance from the vertical line through
the middle of T1 and the centre of the S1 endplate (T1V/S): r=0.71, p<0.0001. Of
the 20 patients with plumb line results indicating coronal imbalance, 11 (55%)
had a normal gravity line-to-HA distance. Of the 33 patients with normal plumb
line results, 7 (21%) had an abnormal gravity line-to-HA distance. CONCLUSION:
The results of this study validate gravity line determination from biplanar
radiographs in a population with AIS. Plumb line position correlated
significantly with gravity line position but was less accurate for guiding surgical decisions.
CI - Copyright (c) 2018 Elsevier Masson SAS. All rights reserved.

Langue : FRANCAIS