Study design: Report of 2 cases.
Objective: To report the usefulness of time-spatial labeling inversion pulse magnetic resonance imaging (T-SLIP MRI) for detection of the communicating hole(s) of spinal extradural arachnoid cysts (SEACs).
Summary of background data: SEACs normally communicate with the subarachnoid space via small communicating hole(s) in the dura. It is necessary to identify the accurate locations of these communicating hole(s) before attempting to close them through limited laminotomy/laminectomy. Myelocomputed tomography or conventional MRI may fail to detect the locations of the hole(s) because they comprise small dural defects.
Methods: Case 1: A 33-year-old female presented with an SEAC at the T11–L2 vertebral level. Case 2: An 82-year-old female presented with an SEAC at T12–L4 vertebral level.
Results: Case 1: T-SLIP MR image of the left parasagittal plane (not the midsagittal or right parasagittal plane) revealed cerebrospinal fluid flow from the subarachnoid space into the cyst at L1. After limited laminotomy at T12–L1 and partial cyst resection, we identified 2 contiguous dural holes immediately medial to the left L1 pedicle; this corroborated the preoperative T-SLIP MRI findings. The holes were sutured. Postoperative conventional MR image confirmed significant cyst shrinkage. Case 2: T-SLIP MR image revealed a curved line at the L1 pedicle in the right parasagittal plane. After L1 laminectomy and partial cyst resection, a dural hole was identified L1 pedicle, which was in agreement with the preoperative T-SLIP MRI findings. After surgery, the lower extremity pain disappeared. Postoperative conventional MR image revealed significant cyst shrinkage.
Conclusion: T-SLIP MRI is useful for detection of the communicating hole(s) of SEACs.
Level of evidence: N/A.