Extraforaminal with or without foraminal disk herniation: reliable MRI findings.
OBJECTIVE
The purpose of our study was to evaluate spinal MR images for extraforaminal disk herniation with or without foraminal disk herniation to determine the reliable MRI findings.


METHODS
Thirty-five patients with extraforaminal with or without foraminal disk herniation confirmed at radiculography or surgery between March 2005 and July 2007 underwent spinal MRI. We assessed the morphologic features of the disk, changes in nerve root thickness, epidural fat obliteration surrounding the nerve root, and displacement of the nerve root in the foraminal and extraforaminal zones.


RESULTS
Mixed disk herniation was found in 23 patients, and purely extraforaminal herniation was found in 12 patients. Focal eccentricity of the disk contour was identified in 32 patients (91%). Change in the nerve root thickness was found in 30 patients (86%). The nerve roots were displaced in 22 patients (63%), and the original location was maintained in nine patients (26%). Differentiation between the disk and the nerve root was poor in four of the 35 patients (11%). Obliteration of the epidural fat surrounding the nerve root was present in all patients.


CONCLUSIONS
The presence of extraforaminal with or without foraminal disk herniation should be ascertained on the basis of the following MRI findings: focal eccentricity of the disk contour, obliteration of epidural fat surrounding the nerve root, change in the thickness of the nerve root, and displacement of the nerve root.
Lee
In Sook
IS
Department of Radiology, School of Medicine, Pusan National University, Medical Research Institute, 1-10 Ami-Dong, Seo-Gu, Busan, Republic of Korea.
Kim
Hak Jin
HJ
Lee
Jung Sub
JS
Moon
Tae-Yong
TY
Jeon
Ung Bae
UB
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged