Chiari I malformation accompanied by assimilation of the atlas, Klippel-Feil syndrome, and syringomyelia: case report.
BACKGROUND
Chiari I malformation, accompanied by superposed bony anomaly of the craniovertebral junction, is comparatively rare. We report a case of Chiari I malformation accompanied by assimilation of the atlas, Klippel-Feil syndrome, and syringomyelia.


METHODS
The patient was a 61-year-old woman demonstrating numbness of the extremities, sensory impairment, muscular weakness, and tendon hyper-reflexia. X-ray images and CT scans demonstrated assimilation of the atlas to the occipital bone, C2 and C3 fusion, abnormal passage of the vertebral arteries, and an anomalous bony mass on the right lateral mass of the atlas protruding into the spinal column. The odontoid process was also deviated to the left. Magnetic resonance images demonstrated bilateral descent of the cerebellar tonsils and syringomyelia extending from C6 to T8. Computed tomographic scans with the head rotated to the right demonstrated increased narrowing of the vertebral column caused by the right lateral mass of the atlas, and MR images confirmed exaggerated deformation of the spinal cord at the same region. This deformation manifested no neurologic symptoms, and we therefore performed foramen magnum decompression and duraplasty using Gore-Tex (W.L. Gore & Associates, Inc., Flagstaff, AZ). In the early postoperative period, neurologic symptoms improved.


CONCLUSIONS
We believe it is important that a treatment plan for Chiari I malformation accompanied by bony anomaly of the craniovertebral junction be determined based on morphologic investigation of the region supplemented by dynamic imaging-based evaluation of instability, or a careful inspection for atypical passage of the vertebral arteries, a frequent site of complication.
Kagawa
Masahiro
M
Department of Neurological Surgery, Kagawa University, Miki-cho, Kagawa, 761-0793, Japan. mku@oak.dti.ne.jp
Jinnai
Takahiro
T
Matsumoto
Yoshihito
Y
Kawai
Nobuyuki
N
Kunishio
Katsuzo
K
Tamiya
Takashi
T
Nagao
Seigo
S
D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D001270:Cervical Atlas / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D019299:Decompression, Surgical; D005260:Female; D005539:Foramen Magnum / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006801:Humans; D007714:Klippel-Feil Syndrome / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D013595:Syringomyelia / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed