PMC9731825_01
Preoperative radiographies. Lateral and anteroposterior imaging demonstrating the severe kyphoscoliosis with the angle in the tract T5-T6 and some pre-existing malformations at cervical level.
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A three-year-old child with suspicious Shinzel-Giedion syndrome presented with a severe thoracic kyphoscoliosis with the angle in the tract T5-T6 (Fig. 1). The spine CT scan (see Fig. 1) revealed severe angular thoracic kyphosis with the angle in the tract T5-T6 which were slightly reduced in height anteriorly with a tendency to an anterior wedge shape.
Motor-evoked potential (MEPs) from the right and left side. MEPs are recorded in prone position at time prior to the alert (A), at alert (B) and after the repositioning of patient (C). At alert, note loss of responses in lower limbs and no changes in upper limbs. After the reposition of patient, there is a complete recovery of evoked potentials. Muscles illustrated from left to right were: abductor digiti minimi (ADM), iliopsoas (IP), rectus femoris (RF), tibialis anterior (TA) and adductor hallucis (AH). The top is the right side, the bottom, the left side.
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MEPs showed good morphology and reproducibility (Fig. 2A). Only bilateral ADM was preserved (Fig. 2C).
Upper limb somatosensory evoked potentials obtained by ulnar nerve stimulation at the wrist (ULSSEPs). The potentials did not change at alert and were stable during the course of surgery. Here represented the left and right side, respectively.
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Posterior tibial and median nerves SEPs were also reproducible bilaterally (Fig. 3, Fig. 4A). After twenty minutes from the beginning of the procedure, while muscles were stripped off to reveal facet and transverse processes, lower limb motor responses disappeared, immediately followed by a significant decrease (under 50% from baseline) of lower limb somatosensory potentials (Fig. 3, Fig. 4C).
Lower limb somatosensory evoked potentials obtained by tibial nerve stimulation at the ankle (LLSSEPs). They recorded in prone position (A) 20 min prior to the alert (B), at alert (C) and after the repositioning of patient (D). After the change of position of patient, a normalization of evoked potentials could be seen. Left and right side are represented, respectively.
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View of pads with patient in prone position on the surgical table. A. Gel rolls are placed one across the chest above the level of axilla and the other one across the iliac crest. B. The chest is optimally placed centered over two parallel pads.
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After supine recordings, the patient was placed prone on the surgical table, supported by gel rolls placed one across chest just above the level of axilla and one across iliac crest (see Fig. 5A). Chest was placed on parallel rolls and particular attention was paid to the neck placement, in a position with flexion limited to less than 15  from horizontal (Fig. 5B).