Surgical outcomes of foramen magnum decompression for syringomyelia associated with Chiari I malformation: relation between the location of the syrinx and body pain.
BACKGROUND
There have been few reports about the relation between the morphology of syrinxes and body pain in syringomyelia associated with Chiari I malformation. To investigate this phenomenon, the relation between the location of the syrinx and body pain before and after foramen magnum decompression (FMD) were evaluated.


METHODS
The subjects were 20 patients with Chiari I malformation associated with syringomyelia who underwent FMD. The morphology of the syrinxes was classified into three types - enlarged type, which was a distended syrinx at the central spinal cord; deviated type, which was a deviated syrinx posterolaterally within the spinal cord; central type, which was a small syrinx at the central canal of the spinal cord - based on axial magnetic resonance imaging (MRI). Preoperative and postoperative clinical symptoms and the body pain were evaluated by the Japanese Orthopaedic Association (JOA) score and a visual analogue scale (VAS) prospectively.


RESULTS
Preoperative and postoperative JOA scores showed no statistically significant differences between the three syrinx types. Intensity of body pain evaluated by the VAS showed that patients with a deviated-type syrinx on pre- and postoperative MRI tended to be associated with more intense pain than the other two types.


CONCLUSIONS
It was indicated that pain before and after surgery is more intense when the syrinx is deviated toward the spinal dorsal horn as seen on MRI.
Ono
Atsushi
A
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Numasawa
Takuya
T
Wada
Kanichiro
K
Yokoyama
Toru
T
Takeuchi
Kazunari
K
Suetsuna
Futoshi
F
Ueyama
Kazumasa
K
Toh
Satoshi
S
D000328:Adult; D000368:Aged; D001139:Arnold-Chiari Malformation / Q000150:complications / Q000601:surgery*; D001270:Cervical Atlas / Q000601:surgery; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D005539:Foramen Magnum / Q000601:surgery*; D006801:Humans; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D011446:Prospective Studies; D013595:Syringomyelia / Q000145:classification* / Q000209:etiology / Q000601:surgery*; D055815:Young Adult