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Intraosseous Fluid Sign Predicts Dynamic Vertebral Body Fracture Mobility 2013

Category General Spine Jill M. Stein, MD
Lubdha Shah, MD
Purpose Corticocancellous disruption and weakened trabecular bone due to osteoporosis or a marrow replacement process may manifest as an intraosseous fluid sign on CT and/or MRI. This may predict dynamic mobility of vertebral body fractures. Awareness of this potential vertebral collapse may affect patient management. Materials & Methods Following IRB approval, the RIS was queried for “fracture” in CT of the thoracic or lumbar spine from March 2011 to 2012. Those CT cases with acute or subacute (< 1 month) fractures and follow-up lateral upright radiographs within one week, with or without MRI, were included. Flexion-distraction injuries were excluded. The fracture type and chronicity were categorized as compression or burst and acute or subacute, respectively. The CT and MRI exams, if available, were evaluated for intraosseous fluid attenuation and signal intensity, respectively. Lateral upright radiographs within one week of the initial imaging were assessed semiquantitatively for further vertebral height loss. A Fisher’s exact test was performed. Results The study population included 17 females and 16 males with an average age of 55 years. Spinal segmental locations of the fractures were thoracic and lumbar. There were 41 fractures, of which 23 were compression fractures and 18 burst-type fractures. Of these patients, 17/41 (41%) had the fluid sign, 11 of whom (59%) demonstrated dynamic vertebral height loss on upright radiographs. All of the patients with a fluid sign and dynamic vertebral body height loss displayed less than 50% loss of height. Three cases showed dynamic vertebral height loss but did not have the fluid sign (13%). Of those patients with dynamic loss of vertebral height, the majority (93%) of patients were treated conservatively. Persistent back pain required kyphoplasty in 1 patient and spinal fixation in 2 patients. Fluid sign predictive of dynamic vertebral body mobility was found to be statistically significant (p<0.05). Conclusion Those patients with an intraosseous fluid sign on CT with or without MRI have an increased risk of dynamic mobility of the vertebral body fracture on follow-up upright radiographs compared to those patients without an intraosseous fluid sign. Vertebral body height loss was less than 50%. Radiologists need to be aware of the predictability of this dynamic vertebral body height loss, which can be suggested by the intraosseous fluid sign. References 1) Malghem J, Maldague B, Labaisse MA, Dooms G, Duprez T, Devogelaer JP, Vande Berg B. Intravertebral vacuum cleft: changes in content after supine positioning. Radiology. 1993 May;187(2):483-7. 2) Chen YJ, Lo DF, Chang CH, Chen HT, Hsu HC. The value of dynamic radiographs in diagnosing painful vertebrae in osteoporotic compression fractures. AJNR Am J Neuroradiol. 2011 Jan;32(1):121-4. 3) McKiernan F, Jensen R, Faciszewski T. The dynamic mobility of vertebral compression fractures. J Bone Miner Res. 2003 Jan;18(1):24-9. Mentored Award Question 1 No Response Question 2 No Response