Iaf. Stokes et al., CHANGES IN SHAPE OF THE ADOLESCENT IDIOPATHIC SCOLIOSIS CURVE AFTER SURGICAL-CORRECTION, Spine (Philadelphia, Pa. 1976), 19(9), 1994, pp. 1032-1038
Study Design. The effect of spinal instrumentation in idiopathic scoli
osis was studied in 21 patients who had Harrington instrumentation and
15 who had Wisconsin-Drummond instrumentation. Objective. Radiographs
were analyzed to determine if the frontal and transverse plane shape
of the scoliosis curve was changed by surgery, with and without segmen
tal fixation. Summary of Background Data. Previous reports were based
on frontal plane measurements of the curve (Cobb angle). The study rep
orts correction in the frontal plane (Cobb angle) and transverse plane
(apical vertebral rotation), as well as the regional distribution of
the correction. Methods. Radiographs before surgery, soon after, and b
etween 5 and 48 months after surgery were marked and digitized to meas
ure the regional distribution of the frontal plane shape and transvers
e plane vertebral rotation. Results. Despite improvement in the magnit
ude of the deformity, the scoliosis curve shape remained almost consta
nt postoperatively. There was minimal correction of the apical vertebr
a axial rotation in either group. Conclusion. This study documents tha
t although the Harrington and Wisconsin-Drummond instrumentation syste
ms decrease the Cobb angle, they do not change the shape of the curve
or correct apical vertebra axial rotation. Newer instrumentation desig
ns need to look beyond the Cobb angle as the only measure of outcome.