Chiari malformation, 6 months post decompression, new neck pain and headache. There are postsurgical changes of Chiari 1 decompression with suboccipital craniectomy and removal of the posterior arch of C1. There is a CSF signal intensity fluid collection in the surgical bed consistent with a pseudomeningocele and has decreased in size since 7/24/2015, currently measuring approximately 16 x 35 mm (sagittal plane), previously 33 x 57 mm. The cerebellar tonsils abut the dorsal aspect of the dura which may be related to scarring, with diminished CSF flow dorsally at the foramen magnum. There remains good biphasic CSF flow ventrally at the foramen magnum. CSF flow sequence also demonstrates flow extending into the pseudomeningocele. The cervical spinal cord has normal signal characteristics and overall morphology. No evidence of syrinx.Vertebral body heights and alignment in the cervical spine are normal. Bone marrow signal is within normal limits. Trace disc bulges are present. There is however no spinal canal or neural foraminal stenosis at any level.
1. Postoperative changes of Chiari decompression. There remains diminished CSF flow dorsally at the foramen magnum. The cerebellar tonsils abut the dorsal dural margin, possibly related to scarring.2. Decrease in size of pseudomeningocele compared to 7/24/2015.