Incidentally identified syringomyelia associated with Chiari I malformations: is early interventional surgery necessary?
OBJECTIVE
The purpose of this study was to analyze clinical data and magnetic resonance imaging (MRI) findings for patients with asymptomatic, incidentally identified syringomyelia associated with Chiari I malformations who were monitored for more than 10 years, and to clarify the natural history of these lesions.


METHODS
The clinical records of nine patients who had not been surgically treated and were regularly subjected to neurological and MRI examinations were analyzed. In MRI studies, the axial diameter of the syrinx at the widest level, the longitudinal extent of the syrinx, and the extent of tonsillar herniation into the spinal canal were analyzed. As a control, MRI findings for 11 patients with symptomatic syringomyelia associated with Chiari I malformations who had been surgically treated were also analyzed, and these MRI parameters were statistically compared between the asymptomatic and symptomatic groups.


RESULTS
One patient underwent surgery, because of neurological changes, 7 years after the first visit. None of the remaining patients demonstrated any neurological change during the follow-up period (11.2+/-0.7 yr), and all of them have been faring well without surgery. No statistically significant differences in MRI findings between the asymptomatic and symptomatic groups were observed.


CONCLUSIONS
The long-term clinical courses of patients with asymptomatic, incidentally identified syringomyelia associated with Chiari I malformations were observed to be benign. MRI parameters did not provide predictable values to recommend interventional surgery. Unless changes in neurological or MRI findings are detected, early interventional surgery is not necessary.
Nishizawa
S
S
Department of Neurosurgery, Hamamatsu University School of Medicine, Shizuoka, Japan. nisizawa@hama-med.ac.jp
Yokoyama
T
T
Yokota
N
N
Tokuyama
T
T
Ohta
S
S
D000293:Adolescent; D000328:Adult; D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000601:surgery*; D001921:Brain / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods; D012852:Sinusitis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D013595:Syringomyelia / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome