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Snake eye appearance - residue of compressive myelopathy post surgical decompression

Case contributed by Chris O'Donnell
Diagnosis certain

Presentation

Previous operation - fusion of cervical vertebra. Now radiculopathy and numbness in both hands.

Patient Data

Age: 70 years
Gender: Male

The patient has had previous surgical intervention at C6/7 by way of anterior discectomy and fusion. There has been reasonable decompression of the spinal canal at this level, however, the cord is atrophic and contains foci of increased T2 signal at the level of the C6/7 disc on either side of midline (snake eye appearance) together with further similar abnormal T2 signal within the cord at the level of the C6 vertebral body.  Appearances are indicative of compressive myelomalacia.

At C5/6 (level above surgery) there is substantial canal stenosis due to broad-based disc bulging producing at least moderately severe cord compression. A central disc protrusion at C4/5 also causes moderate anterior cord encroachment.

At C3/4 there is gross central disc extrusion with very severe cord compression. Subtle cord parenchymal T2 brightening indicative of edema. This is a very substantial finding and will likely require surgical intervention.

Case Discussion

Snake eye appearance (SEA) is a result of severe long-standing compression of the cervical spinal cord (usually due to spondylosis or ossification of the posterior longitudonal ligament).  It is characterized by cystic necrosis leading to cystic myelomalacia and is thought to have an ischemic (venous) as well as compressive etiology.  The cystic change is symmetrical and involves the mid-cord grey matter, conferring a poor prognosis by way of muscle weakness recovery following surgical decompression.

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