Snake-Eye Myelopathy and Surgical Prognosis: Case Series and Systematic Literature Review

Abstract

The prognostic value of “snake-eyes” sign in spinal cord magnetic resonance imaging (MRI) is unclear and the correlation with different pathological conditions has not been completely elucidated. In addition, its influence on surgical outcome has not been investigated in depth. A literature review according to PRISMA (Preferred reporting items for systematic review and meta-analysis protocols) guidelines on the prognostic significance of “snake-eyes” sign in operated patients was performed. Clinical, neuroradiological, and surgical data of three institutional patients, were also retrospectively collected. The three patients, with radiological evidence of “snake-eyes” myelopathy, underwent appropriate surgical treatment for their condition, with no new post-operative neurological deficits and good outcome at follow-up. The literature review, however, reported conflicting results: the presence of “snake-eyes” sign seems a poor prognostic factor in degenerative cervical myelopathy, even if some cases can improve after surgery. “Snake-eyes” myelopathy represents a rare form of myelopathy; pathophysiology is still unclear. The frequency of this myelopathy may be greater than previously thought and according to our literature review it is mostly a negative prognostic factor. However, from our experience, prognosis might not be so dire, especially when tailored surgical intervention is performed; therefore, surgery should always be considered and based on the complete clinical, neurophysiological, and radiological data.

Keywords

• snake-eye
• owl sign
• Hirayama disease
• degenerative cervical myelopathy (DCM)