The significance of increased fluid signal on magnetic resonance imaging in lumbar facets in relationship to degenerative spondylolisthesis.
METHODS
Retrospective radiographic review of consecutive patients with universally applied standard.


OBJECTIVE
To define MRI findings at the facet joints that may suggest abnormal sagittal plane translation seen on standing lateral flexion-extension (SLFE) radiographs.


BACKGROUND
MRI findings, including facet joint orientation, facet joint osteoarthritis, and the presence of synovial cysts, have all been linked with degenerative spondylolisthesis (DS). MRI can also detect facet joint effusion; however, there has not been a study specifically addressing the association of facet fluid signal to degenerative spondylolisthesis (DS).


METHODS
MRI and SLFE films of all patients seen at a single institution for an orthopedic spine consultation over a 2-year period were analyzed. The presence of facet effusions, synovial cysts, increased intensity within the interspinous ligament, degenerative changes at the facets, and anterior sagittal plane translation were all recorded. The data were analyzed to determine if there was a significant association between the presence of DS and the following: facet effusion, degenerative changes of the facets, synovial cysts, increased signal in the interspinous ligament, age, and gender.


RESULTS
There were 139 patients without DS at (NegDS) and 54 with DS (PosDS) on SLFE films at L4-L5 (n = 193). PosDS patients were more likely to be older (P < 0.0001), female (P = 0.0042), have synovial cysts (P < 0.0001), have higher osteoarthritis grade (P < 0.0001), and have larger facet effusion size (P < 0.0001). For both groups, facet joint effusions were also found to be significantly larger in patients with Grade 2 or less osteoarthritis, than in patients with Grade 3 osteoarthritis. Twenty-two percent of the listheses were not detectable on supine MRI.


CONCLUSIONS
Large (> 1.5 mm) facet effusions are highly predictive of degenerative spondylolisthesis at L4-L5 in the absence of measurable anterolisthesis on supine MRI. A clinically measurable facet effusion (> or = 1 mm) suggests the need for SLFE films to diagnose degenerative spondylolisthesis that can be missed with supine positioning on MRI.
Chaput
Christopher
C
Department of Orthopedic Surgery, Scott and White Clinic and Memorial Hospital, Temple, TX 76508, USA. cchaput@swmail.sw.org
Padon
Derek
D
Rush
Jeremy
J
Lenehan
Eric
E
Rahm
Mark
M
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001175:Arthrography; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008023:Ligaments, Articular / Q000473:pathology; D016015:Logistic Models; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications* / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013168:Spondylolisthesis / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D016683:Supine Position; D013581:Synovial Cyst / Q000150:complications* / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D021801:Zygapophyseal Joint / Q000473:pathology*