 Again seen are remote postoperative findings related to prior laminectomies at T8 to T12. Again seen is displacement of the thoracic cord anteriorly at T8 to T11-T12 disk space. There are septations within the thecal sac with suggestion of posterior arachnoid cyst in this region. There is severely diminished caliber of the lower thoracic cord with linear low T2 signal abnormality at T9 and mid T11 where the cord caliber is markedly thinned (up to 3 mm) and abuts the ventral surface of the spinal canal. Conus is not clearly demarcated given the extent distal cord myelomalacia and clumping of the cauda equina nerve roots. Appearance is unchanged. No thoracic syrinx. There is normal alignment of the thoracic spine with a benign homogeneous osseous marrow signal. Small central disk protrusion at T9-T10 and mild disk bulges at T10-T11 and T11-T12 are noted. Findings are not significantly changed from prior study. Prone images demonstrate mild anterior motion of the mid thoracic cord. No significant change is seen in the anterior positioning of the lower thoracic cord at T9-T10 and T10-T11 as well as the proximal cauda equina nerve roots at T11-T12, which may be dorsally tethered.
Again seen is evidence of intradural septations in the lower thoracic spinal canal and formation of arachnoid cysts. The severely myelomalacic lower thoracic cord appears plastered anteriorly to the ventral dural margin from T9-T10 to T10-T11 which may be related to the posterior arachnoid cyst or ventral scarring. Ventral transdural herniation not excluded. More inferiorly, the clumped upper cauda equina nerve roots at T11-T12 approximate the dorsal dural surface and do not demonstrate anterior motion on the prone sequence suggesting tethering. Overall no significant change since 12/20/2014.