MR abnormalities of the intervertebral disks and adjacent bone marrow as predictors of segmental instability of the lumbar spine.
OBJECTIVE
To assess whether MR abnormalities of the intervertebral disks and adjacent bone marrow can predict segmental instability of the lumbar spine as diagnosed on functional radiographs.


METHODS
A consecutive review was made of 60 patients examined with MR imaging and with lateral flexion and extension views of the lumbar spine. Sagittal T1- and T2-weighted images were evaluated blindly with regard to abnormalities of the intervertebral disk and the adjacent bone marrow. Segmental instability was diagnosed when a.p. translation of 3 mm or more was present on the functional radiographs. Moreover, the presence of osteophytes was evaluated on lateral standard radiographs.


RESULTS
Of a total of 300 segments, 32 (10.7%) were unstable. Anular tears were the most relevant MR finding. Their sensitivity, specificity, and positive and negative predictive values for segmental instability were 18.8%, 97.0%, 42.9% and 90.9%. The corresponding values for traction osteophytes were 12.5%, 98.1%, 44.4% and 90.4%. Abnormalities of bone marrow were not significantly related to segmental instability (p=0.35).


CONCLUSIONS
Functional radiographs should be considered in patients with anular tears or traction osteophytes. No correlation was found between segmental instability and abnormalities of bone marrow adjacent to the endplates.
Bräm
J
J
Department of Diagnostic Radiology, Orthopedic University Clinic Balgrist, Zurich, Switzerland.
Zanetti
M
M
Min
K
K
Hodler
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D007593:Joint Instability / Q000175:diagnosis* / Q000209:etiology; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011859:Radiography; D015203:Reproducibility of Results; D013122:Spinal Diseases / Q000175:diagnosis* / Q000209:etiology; D013128:Spinal Osteophytosis / Q000175:diagnosis