Article
Defining the line between Hydromyelia and Syringomyelia. A differentiation possible based on electrophysiological and magnetic resonance imaging studies
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Published: | May 20, 2009 |
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Objective: With the frequent use of magnetic resonance imaging (MRI), patients with subtle and diffuse symptoms due to small syrinx cavities increasingly present to neurosurgical care. In this respect a dilated central canal – called hydromyelia – must be separated from patients with true syringomyelia with an underlying disorder as they do not share clinical and radiological features. We hypothesize that a differentiation of these two entities with distinct diagnostic tools is possible.
Methods: To describe the entity of hydromyelia, we excluded all patients from the syringomyelia database with any obvious cause of a syringomyelia, any objective neurological deficits on clinical examination, pathological results on electrophysiological monitoring (SSEP, MEP, silent periods) or a widening of the spinal cord cavity of more than 5 mm on MR imaging (routine acquisitions with FLAIR, T1-/T2 weighted images, CINE/CISS-studies). Life quality in patients was assessed through standardized SF-36 questionnaires and a Syringomyelia Disability Index (SDI).
Results: From 142 patients with Syringomyelia 40 patients (14 males/ 26 females) matched all criteria of a hydromyelia. With a mean age of 36.7 years (range 11-62) they almost all present with pain (82%) or dysaesthesia of the limbs, with some had an incidental finding (18%). Over a follow-up time of 36.9 months (range 6-93) there was no neurological or radiological deterioration. Moreover compared to syringomyelia, improvement of life quality with adequate conservative treatment was noticed.
Conclusions: Patients with a dilated central canal do not share any feature with patients harboring a syringomyelia. As a hydromyelia does not represent a disease with an underlying pathology, no clinical or radiological progression has been seen. With sophisticated diagnostic tools to rule out any pathology this subset of patients can be identified.