PMC9662851_01
(A) Preoperative T2-weighted MRI sagittal image demonstrated posterior compression of the spinal cord by the OYL at Th2/3. Syringomyelia was observed at C7/Th1. The dotted lines X and Y indicate the location of the axial slices in (E) and (C), respectively.
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(B) (C) The OYL (arrow) at Th2/3 compressed the spinal cord, causing severe spinal canal stenosis.
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(D) CT image showed the OYL (arrow) at Th2/3.
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(E) An intramedullary syrinx (arrow) was formed.
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MRI: magnetic resonance imaging, OYL: ossification of the yellow ligament, Th: thoracic, C: cervical, CT: computed tomography
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MR (magnetic resonance) images (Fig. 1A) and Computed tomography (Fig. 1B) at the cervical (C) and thoracic (Th) vertebral levels showed that an ossification of the yellow ligament (OYL) had severely compressed the spinal cord in the dorsal direction (Fig. 1B-D). Furthermore, the images revealed that a syringomyelia had developed at the C7-Th1 level (Fig. 1A, E), on the cranial side of the OYL.
(A) (B) CT image and its three-dimensional reconstructed image after the first operation. The Th2 lamina was opened, and the OYL was resected. Laminectomy was performed at Th2 (arrow).
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(C) T2-weighted MRI sagittal image showed a scalpel-like deformity in the spinal cord at the Th2/3 level. This "scalpel sign" is the radiological feature of arachnoid web. The dotted line shows the level of the axial image. A residual syringomyelia (arrowhead) was noted.
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CT: computed tomography, Th: thoracic, OYL: ossification of the yellow ligament, MRI: magnetic resonance imaging
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Posterior decompression was performed by laminectomy of Th2, and the OYL lesion was removed (Fig. 2A, B). However, although the cyst-like membranous lesion had cleared, it continued to compress the spinal cord dorsally, resulting in the indentation of the spinal cord that resembled a "scalpel sign" (Fig. 2C).
(A) Intraoperative microscopic image showed a tough, non-cystic, membranous tissue passing transversely and compressing the dorsal spinal cord. The membranous tissue was adhered to the intact arachnoid membrane in the upper and lower spinal cord regions. The asterisk indicates the cranial side.
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(B) Intraoperative microscopic image after total resection of the arachnoid web.
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(C) (D) Pathological examination of the resected arachnoid web revealed a tough membranous tissue with arachnoid-like epithelium.
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A tough membranous structure, which had adhered to the arachnoid membrane, was observed in the dorsal spinal cord after the dural opening (Fig. 3A). After removal of the membranous lesion, the compression of the spinal cord was fully relieved (Fig. 3B). Pathological examination of the membranous lesion identified epithelial tissue without a tumor or infectious lesion, which was consistent with an arachnoid cyst (Fig. 3C, D).
(A) T2-weighted MRI sagittal image acquired at 1 year after operation. Syrinx was remarkably shrunken. The dotted line indicates the location of the axial slice in (B).
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(B) T2-weighted MRI axial image obtained at 1 year after operation.
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MRI: magnetic resonance imaging
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After the second surgery, the syrinx shrunk further (Fig. 4).