Findings:
Head:
Previous suboccipital craniectomy with adequate decompression, currently without cerebellar tonsillar herniation or compression of the brain stem. No hydrocephalus or midline shift.
The brain parenchyma is unremarkable. No diffusion restriction.
The pituitary gland is normal.
The orbits, paranasal sinuses and mastoid air cells are clear.
No bony abnormality is seen.
Cervical and thoracic spine:
Previous C1 laminectomy. Underdeveloped C2/3 disc with fused posterior elements typical of a block vertebra.
Moderate dilatation of the central canal of the spinal cord extending from C1 to T10/11 levels, more prominent in the cervical and upper thoracic spinal cord.
Broad-based disc protrusion is seen at C5/6 and C6/7 without any relevant stenosis or nerve root impingement.
Scoliotic deformity of the thoracic spine with its convexity to the right is noted. The central canal and neural exit foramina are widely patent.
No paravertebral abnormality is identified.
Conclusion:
Previous suboccipital craniectomy and C1 laminectomy with adequate posterior fossa decompression without cerebellar tonsillar herniation or midbrain/cord compression. No hydrocephalus.
Large cervicodorsal syrinx extending from C1 to T10/11 level.