Spinal subdural hygroma.

A spinal subdural hygroma is a rare entity. In this review, we try to contribute to the pooling of current knowledge about spinal subdural hygroma, from embryology and physiology until radiological detection and treatment. The relevant articles in the literature regarding spinal subdural hygroma were reviewed, using a sensitive search strategy on Internet databases. A spinal subdural hygroma is associated with trauma, iatrogenic causes, spontaneous intracranial hypotension headache, and probably meningitis. MR imaging is the golden standard for diagnosis. Treatment of the hygroma is almost always conservative and surgery is seldom necessary, however treating the underlying cause is important. The physiology, in spite of numerous suggestions and hypotheses in literature, remains unclear. The prevalence of spinal subdural hygroma is also still unknown. Only a few articles deal with spinal subdural hygroma, because it is an uncommon entity, without specific symptoms. Probably it is often not diagnosed because of the frequent association with other cranial or spinal pathologies and the need for high-resolution imaging. More research is required to examine the prevalence, importance, and pathophysiology of spinal subdural hygroma.