Female, 32 years old, with Chiari malformation status post decompression, history of spinal AVM resection. Although the history indicates prior Chiari decompression, no definite related surgical changes are seen. If a suboccipital craniectomy was performed, the amount of bone removed was small. The posterior arch of C1 remains in place.The cerebellar tonsils descend up to 5 mm below the level of the foramen magnum. However, they are not particularly peglike in morphology and there seems to be adequate surrounding CSF space. On cine flow imaging, robust biphasic CSF flow is seen both dorsally and ventrally through the foramen magnum.Postoperative findings are again seen consistent with laminotomy from approximately T11-12 through L2-3. The distal conus and nerve roots of the cauda equina in this area are closely opposed to the dorsal thecal sac which may indicate tethering or adhesions. However, the appearance of these findings is unchanged. No evidence of any new or discrete lesion is seen. The nerve roots of the distal cauda equina also demonstrate a somewhat clumped morphology but this too is unchanged. Please note that a portion of the lower thoracic spine was inadvertently omitted from axial T2 imaging, though the relevant postoperative areas are included.Spinal alignment is anatomic. Vertebral body height and morphology are within normal limits. Marrow signal characteristics are unremarkable. No significant compromise of the spinal canal or neural foramina is detected. A small central disc protrusion at T8-9 is unchanged.
1.Findings are seen compatible with a Chiari I malformation as the cerebellar tonsils do descend up to 5 mm below the level of the foramen magnum. However, tonsillar morphology is within normal limits and there is no evidence of crowding or significant effacement of the CSF spaces. Adequate biphasic flow is seen ventrally and dorsally.2.Although the history indicates prior Chiari decompressive surgery, definitive postoperative findings are not identified. Perhaps a very small suboccipital craniectomy was performed. The posterior arch of C1 remains in place.3.Postoperative findings are again seen in the lower thoracic and upper lumbar spine related to treatment for a spinal AVM. Tethering of the conus and cauda equina to the dorsal thecal sac is unchanged. Likewise, clumping of the more distal cauda equina nerve roots is unchanged and may reflect the sequela of prior arachnoiditis. No new lesions are seen.