Usefulness of cyst-subarachnoid shunt using syringo-subarachnoid shunt tube for symptomatic enlarging ventriculus terminalis: A case report and review of the literature

Abstract

Background: The ventriculus terminalis (VT) is a cystic embryological remnant of the conus medullaris that usually regresses after birth. This structure rarely persists into adulthood and may produce neurological symptoms. We recently encountered three cases of symptomatic enlarging VT.

Case description: The three female patients were 78, 64, and 67 years old. Symptoms included pain, numbness, motor weakness, and frequent urination that gradually worsened. Magnetic resonance imaging revealed cystic dilatations of slow growing VT. These patients showed marked improvement after cyst-subarachnoid shunt using a syringo-subarachnoid shunt tube.

Conclusion: Symptomatic enlarging VT is an extremely rare cause of conus medullaris syndrome and the optimal treatment strategy remains unclear. Surgical management may thus be appropriate for patients with symptomatic enlarging VT.

Keywords: Cyst-subarachnoid shunt; Enlarging ventriculus terminalis; Slow growing; Symptomatic case; Syringosubarachnoid shunt tube.

Figure 1:

Results of magnetic resonance imaging (MRI). (a) T2-weighted sagittal image from 12 years before this presentation shows cystic dilatation of the conus medullaris. (b-1) T1-weighted image. (b-2) T1-weighted image with gadolinium enhancement. (b-3) T2-weighted image. (c) Postoperative T2-weighted images obtained 3 years after surgical treatment reveal regression of the dilatation without evidence of relapse (white bold arrow).

Figure 2:

Cystic dilation of the ventriculus terminalis from an intraoperative view. (a and b) On opening the dura, the expanded conus began herniating outward under pressure, which was relieved by fenestration. (c) Cystsubarachnoid shunt was created using a syringo-subarachnoid shunt tube (diameter: 1.2 mm, length: 40 mm). Black asterisk: Cyst wall, black star: Cauda equina, black arrow: Syringo-subarachnoid shunt tube.

Figure 3:

Preoperative sagittal and axial spinal magnetic resonance imaging demonstrating a cystic lesion near the conus medullaris. (a) Sagittal T1-weighted image with non-contrast sequence. (b) Sagittal T2-weighted image. (c) Axial T2-weighted image. (d) Postoperative sagittal T2-weighted image 2 years after surgery reveals complete regression of the dilation (white bold arrow).

Figure 4:

Sagittal and axial magnetic resonance imaging on admission demonstrating a cystic lesion near the conus medullaris. (a) Sagittal T1-weighted image with non-contrast sequence. (b) Sagittal T2-weighted image. (c) Axial T2-weighted image. (d) Postoperative sagittal T2-weighted image 1 year after surgery shows complete regression of the dilation (white bold arrow).