Female, 25 years old, with tethered cord, low back pain, scoliosis. Evaluate for changes. Posterior fusion instruments are in place extending from the T4 level down to the L4 level. Associated artifact obscures portions of the spine. Evidence of additional surgery is also seen in the lumbar region where the posterior elements are absent beginning at L2 and continuing down to L5. An S-shaped scoliotic curvature of the spine is seen which is predominantly levoscoliotic in the lumbar region with perhaps a mild dextroscoliosis in the thoracic region. Sagittal alignment is within normal limits. Vertebral body heights are preserved. No evidence to suggest marrow edema or pathologic marrow replacement is seen.Findings compatible with split cord malformation (diastematomyelia) are seen. Partial separation of the hemicords begins at the T7 level. The hemicords become completely separated at T12 and then re-unite at the L2 level. No definite evidence of an intervening osseous spur is seen. Image quality is not adequate to exclude the possibility of a thin fibrous septation.Below the L2 level, the re-united cord becomes closely apposed to the dorsal thecal sac. The spinal cord is low lying and reaches at least to the L3 level. On prone imaging, the distal spinal cord and cauda equina nerve roots remain closely apposed to the dorsal thecal sac.A thin T1 hyperintense cord-like structure is evident dorsally beginning at the L4 level compatible with a fatty filum terminale. At the L5 level, there is a gap of approximately 2 cm where no definite fatty filum is seen. However, the fatty filum reappears at the S1 level (see image 12 series 1301).
1.A scoliotic curvature of the spine is demonstrated. Long segment thoracolumbar instrumented fusion has been performed.2.Absent posterior elements in the lower lumbar spine likely represent additional postoperative change though this could also potentially represent congenital dysraphism.3.Findings are seen compatible with split cord malformation. The cord begins to separate into two halves at the T7 level with complete separation evident at T12. The hemicords re-unite at the L2 level. No definite evidence of an intervening osseous spur is seen, though image quality is not adequate to exclude the possibility of a fibrous septation.4.A T1 hyperintense cord like structure in the lower lumbar spine along the dorsal thecal sac likely represents fatty infiltration of the filum terminale. It appears that there is a 2 cm long disruption in this structure which could indicate prior surgical detethering. Alternately, the filum terminale may only be intermittently fatty infiltrated.5.Multiple findings are seen suggesting tethered cord including a low-lying spinal cord, the presence of fatty infiltration of the filum terminale, and lack of cord movement on prone imaging.