Traumatic bilateral facet dislocation of lumbar spine: “double facet sign”

Traumatic bilateral facet dislocation of lumbar spine: “double facet sign”

The Spine Journal 13 (2013) 1705–1707 Traumatic bilateral facet dislocation of lumbar spine: ‘‘double facet sign’’ A 72-year-old man was admitted to ...

773KB Sizes 1 Downloads 46 Views

The Spine Journal 13 (2013) 1705–1707

Traumatic bilateral facet dislocation of lumbar spine: ‘‘double facet sign’’ A 72-year-old man was admitted to the emergency department after a high-impact motor vehicle accident. On admission, he was conscious but confused and hemodynamically unstable. He was paraplegic, and the bulbocavernous reflex was absent. Chest and abdominal computed tomography (CT) revealed multiple rib fractures, lung contusion, hemo-and pneumothorax, bilateral complete L1–L2 facet dislocation, and fractures of the right transverse process, spinous process of L1, and anterior upper end plate of L2. The axial CT scan showed that the superior articular facet of L2 appeared ‘‘naked’’ (Fig. 1). It was called ‘‘naked facet sign’’ in such a case [1]. The opposing articulating surfaces should be clearly seen at the same axial level when the joint is intact bilaterally. However, naked facet sign is when inferior facets related to the involved zygapophyseal joints are optimally visualized on a section above the one in which the superior facets related to the same joint are best. It signifies vertical distraction of inferior articular process and dislocation. In addition, axial CT scan showed nonopposing articular facets at the disc level between L1 and L2 (Fig. 1). It was shown as if inferior articular facet of L1 or superior articular facet of L2 was doubled. Thus, we called it a ‘‘double facet sign.’’ This is

1529-9430/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.07.477

because the L1 inferior articular facet became located in the anterior of the L2 superior articular facet. He was stabilized with transfusion and chest drain placement. Magnetic resonance imaging revealed severe stenosis at L2 with disruption of the anterior longitudinal ligament and posterior ligamentous complex (Fig. 2). Surgery was performed 3 days after injury. We found ruptured capsules of the zygapophyseal joints and the supra-and interspinous ligaments, partial rupture of the ligamentum flavum, and bilateral locked L1–L2 facet joints. Reduction of the dislocation required resecting the superior facet of L2. A posterior fusion with rod and pedicle screw fixation from T12–L3 was performed.

Reference [1] O’Callaghan JP, Ullrich CG, Yuan HA, Kieffer SA. CT of facet distraction in flexion injuries of the thoracolumbar spine: the ‘‘naked’’ facet. AJR Am J Roentgenol 1980;134:563–8.

In-Hoo Ra, MD Woo-Kie Min, MD, PhD Department of Orthopedic Surgery Kyungpook National University Hospital 130 Dongdeok-ro, Jung-gu Daegu 700-721, South Korea FDA device/drug status: Not applicable. Author disclosures: I-HR:Nothing to disclose.W-KM: Nothing to disclose.

1706

I.-H. Ra and W.-K. Min / The Spine Journal 13 (2013) 1705–1707

Fig. 1. (Left) Sagittal computed tomography (CT) scan shows locked facets on L1–L2. The dotted line is the level of cross-section. (Middle Top) It seemed as if one of the inferior articular facets of L1 (upper arrows) or superior articular facets of L2 (lower arrows) was ‘‘doubled’’ at the disc level between L1 and L2 on axial CT scan. (Middle Bottom) The axial CT scan showed that the superior articular facet of L2 appeared ‘‘naked’’ (arrows). (Right) Threedimensional CT reconstruction shows bilateral locked facets (both arrows).

I.-H. Ra and W.-K. Min / The Spine Journal 13 (2013) 1705–1707

Fig. 2. T2-weighted sagittal magnetic resonance imaging shows a disruption of the anterior longitudinal ligament (left arrow) and posterior ligamentous complex (right arrow).

1707