PMC8166278_01
Preoperative radiographs showing lumbar degeneration and instability between the L2/3 segments (A, white arrow) and internal fixation to stabilize the local intervertebral space (B).
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Dynamic lumbar spine X-ray indicated instability between the L2 and L3 segments (Figure 1A). Internal fixation was used to stabilize the local intervertebral space (Figure 1B).
Sagittal T1-weighted (A) and T2-weighted (B) MR images showing posterior disc fibrous annulus rupture and loss of PLL continuity at the L2/3 level. (C) Enhanced MR image showing a "hawk-beak" sign. White arrows indicate disc herniation and associated radiographic changes.
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Sagittal T1- and T2-weighted magnetic resonance imaging (MRI) showed rupture of the posterior disc fibrous annulus and loss of continuity of the posterior longitudinal ligament (PLL) at the L2/3 level (Figure 2A and B). Sagittal gadolinium-enhanced MRI showed large disc protrusion into the ventral dural sac, which appeared as a hawk-beak sign (Figure 2C).
(A) Axial T2-weighted MR image showing the torn PLL (A, white arrow). (B) Enhanced MR image showing a ring sign (B, white arrow).
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The same was observed on axial MRI in which the PLL appeared torn in the left posterior direction, with a large mass squeezing the dura mater (Figure 3A). It also showed peripheral ring enhancement of the sequestered herniated disc (Figure 3B).
(A) A midline durotomy was performed. (B) Smooth surface with hard fragments lodged in the inner wall of the ventral dura (blue arrow). (C) Thinned round defect within the ventral dura (blue arrow). (D) Image showing the sizes of the two herniated disc fragments.
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We performed durotomy according to the preoperative plan, and nerve rootlets were squeezed out of the dorsal dural incision (Figure 4A). From the left dorsolateral view, we observed a smooth surface with hard fragments lodged in the inner wall of the ventral dura (Figure 4B). After extirpating two free fragments with sizes of approximately 1.7x0.8x0.4 and 1.0x0.5x0.4 cm3 (Figure 4D), the cauda equina nerve relaxed and the dura mater slackened. We found a thinned round defect (~8 mm in diameter) within the ventral dura (Figure 4C).
(A) Degenerated fibrocartilage (red box) and hyperplastic inflammatory granulation tissue (blue box) on histopathologic examination (50x magnification). (B) Proliferation of small blood vessels and fibroblasts accompanied by inflammatory cell infiltration (blue box, 100x magnification). (C) Degenerated fibrocartilage and nucleus pulposus tissue (red box, 100x magnification).
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Histopathologic examination of the extruded disc-like material at 50x and 100x magnification revealed that the mass contained degenerated fibrocartilage, nucleus pulposus tissue, and hyperplastic inflammatory granulation tissue (Figure 5A-C).