PMC4929096_01
a Preoperative frontal X-ray of the right 95  thoracic scoliosis. b Postoperative frontal X-ray after index procedure. c Postoperative frontal X-ray after revision procedure and screw removal
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Fig1
The decision was made to decrease the intensity of correction by contouring the rods (Fig. 1b).
Results of sensitive evoked potentials (SEP) after stimulation of both posterior tibial nerves at various times of the surgery. a Results during screws placement, b results during first rod insertion, c results during second rod insertion and spinal curve correction showing a decrease of cortical amplitudes and increase of latencies, d results at the end of the surgical procedure with improved amplitudes and normal latencies
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Fig2
SEP responses decreased considerably. SEP amplitudes decreased 90 %, while latencies increased significantly (Fig. 2).
CT scan showing the gross misplacement of the pedicle screw, which crossed the center of the vertebral canal on axial (a), coronal (b) and sagittal (c) planes. d Same sagittal plane of spinal MRI showing an increased diameter of the syrinx adjacent to a left T5 pedicle screw crossing the spinal canal
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Fig3
Axial, sagittal and coronal planes of a thoracolumbar CT scan confirmed the gross misplacement of the pedicle screw, which crossed the center of the vertebral canal (Fig. 3a-c). Spinal MRI was performed to check the C6 to T7 syringomyelia, which showed an increased diameter of the syrinx adjacent to a left T5 pedicle screw crossing the spinal canal (Fig. 3d).
SEP monitoring showing altered responses at 6 months (b), with decreased amplitudes and increased latencies compared to preoperative values (a). SEP control at final
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Fig4
SEP monitoring showed altered responses, with decreased amplitudes and increased latencies (Fig. 4). SEP explorations performed at final follow-up showed similar responses to those performed before the initial surgery for scoliosis correction (Fig. 4), and final MRI confirmed the stability of syringomyelia.