Idiopathic scoliosis : radiographic, neurophysiologic and psychologic aspects

Abstract

The aim of this thesis was to study brace treatment outcome, the brace effect on electromyographic muscle responses and self image, possible occurrence of somatosensory dysfunction and the descriptive power of surface topography contra radiography, in idiopathic scoliosis.

There were 64 patients in a retrospective 4.8 years brace treatment follow-up, and 39 patients in a retrospective surgically treated group, in which somatosensory evoked potentials (SEP) were studied. 74 patients were included in four prospective studies including interview questionnaire on brace effect on self image; analyses on electromyographic muscle responses on balance perturbation with and without brace; comparisons of Jenoptik-Formetric-videoraster stereography (VRS), Myrininclinometry, Bunnell-scoliometry and radiography; as well as neurophysiological tests including SEP, detailed neurological status with sensibility screening, examination of dystonia, muscle function, thermal and vibration thresholds.

Brace treatment results were good if the patient was compliant. The primary brace induced correction was the most important prognostic factor. The primary correction was equal for prefabricated braces with 0 and 15 degrees lumbar lordosis. The self-image of scoliosis patients before treatment was equal to that of a normal age-matched control group. Bracing had no negative effect on self-image.

VRS could not provide an equivalent to the radiographic Cobb angle but correlation between radiographic apex translation and VRS lateral deviation was statistically significant. Right convex thoracic curves were adequately demonstrated by VRS. Using VRS rotation(max) breakpoint of 8.5 degrees, curves larger than 25 degrees Cobb could be diagnosed with more than 95% security.

Signs of segmental muscle dystony were not found. SEP pathology, indicated in the retrospective study, could not be verified in the prospective study. The only neurophysiologic pathology was found in vibration thresholds as a side asymmetry, which however, was not correlated to the curve side. There was also an asymmetry in electromyography recordings in sternocleidomastoid, rectus abdominis and neck extensor muscles. The brace did not affect this asymmetry nor paravertebral muscle responses otherwise.