The Spine Journal 14 (2014) 1060–1062
Cauda equina and conus medullaris avulsion with herniation after midlumbar chance fracture A 19-year-old woman arrived to our Level 1 trauma center 2 days after a motor vehicle rollover on the US-Mexico border. The patient’s examination revealed absent sensation to light touch and pinprick below T11, 0/5 motor function in bilateral lower extremities (including 0/5 function in bilateral iliopsoas), absent rectal tone, and no appreciable bulbocavernosus reflex. Initial computed tomography revealed an L3 vertebral fracture extending from the anteroinferior end plate through the middle column and posterior vertebral cortex. Bilateral pars interarticularis fractures are noted with the widening of the L2–L3 spinous process interspace (Fig. 1). The patient’s initial imaging did not reveal any significant canal compromise or fragment retropulsion (Fig. 1). Magnetic resonance imaging Short Inversion Time Inversion Recovery (STIR) and T2 sequences revealed complete disruption of the posterior ligamentous complex at the L2– L3 level and a linear hyperintensity within the cord at the T11–T12 level with absent cauda equina nerve roots distally (Fig. 2). Caudal to this lesion, significant intradural hematoma extends posteriorly and dorsally out of the L2–L3 interspace. At this same level, spinal nerve roots are seen extruded into the interspinous space (Fig. 2). In the setting of her complete neurologic injury and the need for continued care of her intra-abdominal injuries, she was indicated for L2–L4 posterior spinal instrumentation (Fig. 3). She did not display any further progression or resolution of her neurologic injuries at 3-month follow-up. In this case, our patient’s clinical examination was indicative of a severe spinal cord injury level at least three levels cranial to the initial radiographic findings. Distraction about the L3 vertebral fracture likely caused the observed neural element disruption, compared with previously described cases citing distal peripheral nerve traction after lower extremity and sacral/pelvic fractures [1–4]. The varied clinical presentation of these injuries requires meticulous clinical
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examination documentation and correlation with imaging studies. In the setting of a compromised posterior ligamentous complex, evaluation for herniation of the neural elements is also prudent.
References [1] Mossey JJ, Nashold BS, Osborn D, Friedman AH. Conus medullaris nerve root avulsions. J Neurosurg 1987;66:835–41. [2] Harris WR, Rathbun JB, Wortzman G, Humphrey JG. Avulsion of lumbar roots complicating fracture of the pelvis. J Bone Joint Surg Am 1973;55:1436–42. [3] Murata Y, Lee M, Mimura M, et al. Partial avulsion of the cauda equina associated with a lumbosacral fracture-dislocation: a case report. J Bone Joint Surg Am 1999;81:1450–3. [4] Finney LA, Wulfman WA. Traumatic intradural lumbar nerve root avulsion with associated traction injury to the common peroneal nerve. Am J Roentgenol 1960;84:952–7.
Bryan K. Lawson, MDa Joel W. Jenne, MDa Christopher J. Koebbe, MDb a Department of Orthopaedics and Rehabilitation Brooke Army Medical Center 3551 Roger Brooke Drive JBSA Fort Sam, Houston TX 78234-6200, USA b Department of Neurological Surgery Brooke Army Medical Center 3551 Roger Brooke Drive JBSA Fort Sam, Houston TX 78234-6200, USA FDA device/drug status: Not applicable. Author disclosures: BKL: Nothing to disclose. JWJ: Nothing to disclose. CJK: Nothing to disclose. Case report approved by the Brooke Army Medical Center Institutional Review Board. No grants or corporate support was used in conducting this study. The views expressed herein are those of the authors and do not reflect the official policy or position of Brooke Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Army, the Department of Defense, or the US Government.
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Fig. 1. (A–C) Left parasagittal, central, right parasagittal computed tomographic (CT) images obtained on presentation, revealing L3 flexion distraction injury with bilateral pars fractures and intraspinous widening. (D) Axial CT image at the L3 vertebral level revealing minimal canal narrowing.
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Fig. 2. (A and B) Sagittal magnetic resonance imaging (MRI) Short Inversion Time Inversion Recovery (STIR) sequence revealing linear hyperintensity within the spinal cord at T11–T12 (yellow arrow), intradural hematoma extending from the L1–L2 interspace (white arrow), and extruded neural elements through the compromised posterior ligamentous complex at L2–L3. (C and D) Sagittal/axial T2 MRI sequence displaying the absence of cauda equina nerve roots distal to the thoracolumbar junction with extruded neural elements (red arrows).
Fig. 3. Postoperative anteroposterior (Left) and lateral (Right) plain radiographs after posterior spinal instrumentation.