PMC7447335_01
Magnetic resonance images at the initial visit.. An irregularly-shaped, isointense fragment on T1- and T2-weighted images is seen in the cerebrospinal fluid (arrowheads). Cauda equina cannot be confirmed in the axial image.
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An irregularly-shaped fragment with iso-intensity on both T1- and T2-weighted images (WI) filled the dural sac at L4-5 (Fig. 1).
Enhanced magnetic resonance images at the initial visit.. The fragment inside the dura mater shows rim enhancement (arrowheads). In addition, the posterior disc wall or the posterior longitudinal ligament at L4-5 is also enhanced by gadolinium (arrow).
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T1WI, the intradural fragment demonstrated rim enhancement (Fig. 2). The posterior longitudinal ligament (PLL) at L4-5 was also enhanced.
Computed tomography after discography at L4-5.. The contrast medium enters the intradural space but does not spread into the subarachnoid space (A: L4-5 disc level, B: Caudal part of L5 vertebra).
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The computed tomogram after the discography showed the contrast medium entering the subdural space but not into the subarachnoid space (Fig. 3), which possibly indicated that the herniation was located between the dura mater and the arachnoid.
Follow-up magnetic resonance image at 40 days, 4 months and 13 months postoperatively.. The intradural herniated mass gradually decreases after surgery. In axial planes, the mass decreases from middle to right side, and cauda equina is clearly seen (arrowheads). There is a discontinuity of dura mater at 4 months and 13 months after onset (arrows). It may indicate a dural defect through which the herniation mass passed.
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The volume of the herniation was significantly decreased at 40 days, 4 months, and 7 months after the initial examination (Fig. 4). Thirteen months after symptom onset, the patient's pain and neurological deficits had completely resolved, and no recurrence was detected by MRI (Fig. 4).