European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Case Reports
Discrepancies of MRI findings between recumbent and upright positions in atlantoaxial lesion. Report of two cases.
Two cases of atlantoaxial (A-A) instability that showed different MRI findings between supine and upright positions are presented. The upright MRI represented the findings corresponding to their symptoms. In A-A lesions, conventional MR images taken in the supine position do not always explain the pathophysiological consequences. The MR images taken in the upright position disclose the actual spinal pathophysiology with gravitational effects.
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Persons with recurrent low back pain (LBP) have been observed to have altered proprioceptive postural control. These patients seem to adopt a body and trunk stiffening strategy and rely more on ankle proprioception to control their posture during quiet upright standing. The aim of this study is to determine the effect of changing postural condition (stable and unstable support surface) on postural stability and proprioceptive postural control strategy in persons with recurrent LBP. ⋯ Persons with recurrent LBP showed significantly different postural control strategies favoring ankle muscle proprioceptive control (ratio closer to 1) instead of paraspinal muscle proprioceptive control (ratio closer to 0) for both standing without foam (ratio ankle muscle/paraspinal muscle control = 0.83) (P < 0.0001) and on foam (ratio ankle muscle/paraspinal muscle control = 0.87; P < 0.0001) compared to healthy individuals (0.67 and 0.46, respectively). It is concluded that young persons with recurrent LBP seem to use the same proprioceptive postural control strategy even in conditions when this ankle strategy is not the most appropriate such as standing on an unstable support surface. The adopted proprioceptive postural control strategy might be effective in simple conditions, however, when used in all postural conditions this could be a mechanism to undue spinal loading, pain and recurrences.
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Case Reports
The value of bilateral ipsilateral and contralateral motor evoked potential monitoring in scoliosis surgery.
Intraoperative monitoring (IOM) of the motor pathways is a routine procedure for ensuring integrity of corticospinal tracts during scoliosis surgery. We have previously demonstrated presence of ipsilateral motor evoked potentials (MEPs) during IOM for scoliosis surgery, but its significance was uncertain. In this case series, we show concurrent ipsilateral and contralateral MEP amplitude changes obtained with cortical stimulation are of value in reducing false positive observations during IOM. The use of this easily recordable MEP is thus advocated as a diagnostic adjunct to contralateral MEPs for scoliosis and spinal surgery.
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According to Lenke classification of adolescent idiopathic scoliosis (AIS), patients with type 5 curve in which the structural major curve is thoracolumbar or lumbar curve with nonstructural proximal thoracic and main thoracic curves, could be surgically treated with selective anterior thoracolumbar or lumbar (TL/L) fusion. This study retrospectively analyzed the radiographies of selective anterior TL/L fusion in 35 cases of AIS with Lenke type 5 curve. Segmental fixation with a single rigid rod through anterior thoracoabdominal approach was applied in all patients. ⋯ The TL/L curve, minor thoracic curve, and LIV title can be improved significantly, with good maintenance of sagittal contour. However, the UIVDA and LIVDA aggravate postoperatively when the trunk rebalances itself during follow-up. The degeneration of LIV disc warrants longer-term follow-up.
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Comparative Study
Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure.
Interspinous implants are used to treat lumbar spinal stenosis or facet joint arthritis. The aims of implanting interspinous devices are to unload the facet joints, restore foraminal height and provide stability especially in extension but still allow motion. The aim of this in vitro study was to compare four different interspinous implants--Colfex, Wallis, Diam and X-Stop--in terms of their three-dimensional flexibility and the intradiscal pressure. ⋯ In contrast, in flexion, lateral bending and axial rotation the values of the range of motion stayed about the values of the defect state. Similarly the intradiscal pressure after implantation was similar to that of the intact specimens in flexion, lateral bending and axial rotation but much smaller during extension. All tested interspinous implants had a similar effect on the flexibility: they strongly stabilized and reduced the intradiscal pressure in extension, but had almost no effect in flexion, lateral bending and axial rotation.