PMC3157089_01
Sagittal (a) and axial (b) T1-weighted MR scans demonstrate an elongated, narrow head with relative flattening of the basal angle and suboccipital bone. Note the crowding of the cervicomedullary junction consistent with a mild Chiari malformation. The subdural hematomas seen on a prior study have resolved
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F1
Imaging included an MR scan of the head which demonstrated dolichocephaly as noted on the clinical examination as well as the presence of the known ventriculoperitoneal shunt [Figure 1].
Sagittal T2-weighted MR scans of the cervical spine demonstrate anomalous right (a) and left (b) vertebral arteries (arrows) dorsal to and impressing into the cord substance. Note the T2 signal change in the adjacent cord. Again seen is the crowding and tonsilar herniation at the cervicomedullary junction consistent with a mild Chiari malformation. No syrinx was present. (c) Axial T2-weighted image of the C1-2 interspace demonstrating anomalous vertebral arteries deforming the dorsal spinal cord. T2-signaling abnormality in the dorsal cord is evident
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F2
There was no syrinx in the spinal cord [Figure 2].
Intraoperative photographs of the dorsal cervicomedullary junction. The cerebellar tonsils and an anomalous posterior inferior cerebellar artery can be seen on the left (rostral). (a) The right (single arrow) and left (double arrows) vertebral arteries can be seen penetrating the dura at C1-2 and passing dorsal to the spinal cord until they nearly touch at midline. They then turn rostrally and anteriorly. (b) After the mobilization of the right vertebral artery, the impression left by the artery in the cord substance can be readily observed (arrows)
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F3
The most striking finding, however, was the course of the vertebral arteries [Figure 3] which entered the cervical canal at the C1-2 level laterally and immediately compressed the dorsal and lateral aspects of the spinal cord on both sides as they converged toward the midline.