Defining the line between hydromyelia and syringomyelia. A differentiation is possible based on electrophysiological and magnetic resonance imaging studies.
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, 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 (n = 142) 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 6 mm on MRI [routine acquisitions with FLAIR, T1/T2-weighted images, Cine and CISS (constructive interference in steady-state) studies]. Life quality was assessed through SF-36 questionnaires and an individualized questionnaire for the clinical history, pain and alternative therapies.


RESULTS
Forty patients (15 males/25 females) matched the criteria of a hydromyelia. With a mean age of 36.7 years (range 11-62), they almost all presented with pain (79%) or dysaesthesia of the limbs, with some having been an incidental finding (10%). Over a follow-up time of 36.9 months (range 6-93) there was no neurological or radiological deterioration.


CONCLUSIONS
Patients with a hydromyelia do not share clinical or radiological characteristics with patients harbouring a true syringomyelia. As 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.
Roser
Florian
F
Department of Neurosurgery, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. f.roser@gmx.de
Ebner
Florian H
FH
Sixt
Carolin
C
Hagen
Jennifer Müller V
JM
Tatagiba
Marcos S
MS
D000293:Adolescent; D000328:Adult; D002574:Cervical Vertebrae; D002648:Child; D003937:Diagnosis, Differential; D018450:Disease Progression; D004558:Electric Stimulation / Q000379:methods; D004568:Electrodiagnosis / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D010147:Pain Measurement / Q000379:methods; D011788:Quality of Life; D012678:Sensation Disorders / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D013116:Spinal Cord / Q000473:pathology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D013595:Syringomyelia / Q000175:diagnosis* / Q000503:physiopathology; D013904:Thoracic Vertebrae; D055815:Young Adult