PMC9534567_01
Preoperative computed tomography (CT) myelography and magnetic resonance imaging (MRI) images. (A-C) CT myelography showed syringomyelia (arrows) and dorsal shift of the spinal cord (arrowheads) due to arachnoiditis in the dorsal leptomeninges. (D-F) T2-weighted MRI without contrast showed syringomyelia (arrows) and a dorsal shift of the spinal cord (arrowheads) due to arachnoiditis in the dorsal leptomeninges. B, T7; C, T9; E, T7; and F, T9.
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Spinal magnetic resonance imaging (MRI) and computed tomography (CT) myelography showed syringomyelia at the T5-T8 level and dorsally tethered spinal cord at the T8-T10 level (Fig. 1).
Surgical findings and intraoperative ultrasound images (Arrow, arachnoiditis ossificans; arrowhead, dura matter; asterisk, spinal cord). Intraoperative sagittal ultrasound image showing hyperintense structures with acoustic shadowing on the dorsal spinal cord (arrow). The spinal cord with syringomyelia can be partially identified (A). After opening the dura matter (arrowhead), the dorsal surface of the spinal cord was covered with arachnoiditis ossificans (arrow) (B-D). The ossified lesion was removed as far as possible without compressing the spinal cord (E). Then, the flow of spinal fluid can be detected by intraoperative sagittal ultrasound imaging (F).
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Intraoperative ultrasound (IOU) revealed a hyperechoic lesion with acoustic shadowing, which blocked the view of the spinal cord, on the dorsal surface of the spinal cord (Fig. 2A). Hard ossified tissue was visualized on the dorsal surface of the spinal cord when the dura mater was incised (Fig. 2B, C). They were also removed, and arachnoidolysis was additionally performed (Fig. 2D, E). At the final stage of surgery, the IOU showed a clear image of the untethered and well-decompressed spinal cord and restoration of CSF pulsation, while the syrinx of the spinal cord was unchanged (Fig. 2F).
Histopathological findings and postoperative computed tomography (CT) and magnetic resonance imaging (MRI) images. Histopathological examination shows ossified tissue along with the bone marrow tissue and scattered epithelial-like cells without atypia around the bone tissue (Hematoxylin & Eosin staining; original magnification: x100) (A). T6-8 laminoplasty, T9 partial laminectomy, and removal of the arachnoiditis ossificans were performed. Postoperative CT shows calcified lesions on the dorsal spinal cord above and below the surgical levels (arrowheads) (B-D). T2-weighted MRI shows an improvement in syringomyelia and a dorsal shift of the spinal cord (E-G). B, T5; C, T7; E, T5; and F, T7.
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A cluster of cells with round, nonatypical nuclei existed around the bone tissue (Fig. 3A). Postoperative CT scans showed a residual ossified lesion on the dorsal surface of the spinal cord at upper and lower levels outside the surgical field (Fig. 3B-D). Postoperative MRI showed the disappearance of syringomyelia and successful untethering of the dorsally tethered spinal cord (Fig. 3E-G).