1996 Volume 45 Issue 1 Pages 73-77
We experienced two cases of extradural arachnoid cysts in the thoracolumbar region.
Case 1: A 13-year-old female suffered from low back pain and progressive weakness of her lower limbs. MRI and myelogram showed a cystic lesion located in the posterior part of the spinal canal which was compressing the spinal cord at the Th12-L3 level. Cine MRI revealed turbulence in the cyst and spinal fluid flow between the subarachnoid space and cyst. We confirmed that the extradural arachnoid cyst communicated with the subarachnoid space. After extirpation of the cyst and closure of the communicating fissure, complete motor recovery was seen and the patient's low back pain disappeared.
Case 2: A 65-year-old female suffered from low back pain and was unable to walk due to palsy of her lower limbs. Although an arachnoid cyst at the Th11-L2 level was suspected from MRI and myelogram, neither turbulence in the cyst nor communication flow was seen in tine MRI. Fluid aspiration improved the palsy of her lower limbs, however MRI taken 3 days later revealed accumulation of fluid and the palsy exacerbated after 3 weeks. Surgery was performed, at which time it was found that the arachnoid cyst communicated with the subarachnoid space. The cyst was extirpated and the connecting pedicle ligated. Complete motor recovery was seen 3 months after surgery.
