Figure 1. Computed tomography scan of pelvis.
Figure 2. Sagittal MRI of spine.
A 56-year-old man presents to the emergency department with severe lower back pain after a fall off a 10-foot ladder 3 days ago. He denies any weakness or numbness in his lower extremities or any bowel or bladder changes. On physical examination, his motor strength and light touch sensation are intact in his lower extremities. He has pain to palpation over the L1 region of his spine with moderate paraspinous spasm. Computed tomography scan of his abdomen and pelvis reveals an L1 burst fracture with bony retropulsion (Figure 1). He also has a pedicle fracture on the left at L1 and a nondisplaced T12 spinous process fracture. Sagittal magnetic resonance imaging (MRI) is shown in Figure 2.
Submit your diagnosis to see full explanation.
A burst fracture is a severe compression fracture that results in disruption of the vertebral body endplate and posterior cortex of the vertebral body. A severe axial force with flexion causes compression of the anterior and middle columns of the spine that can lead to retropulsion of bony fragments into the spinal canal. Stable fractures without neurologic compromise can be treated conservatively with or without a thoracic lumbar sacral orthosis (TLSO) and early mobilization. However, a burst fracture is considered unstable if the patient has neurologic deficits and/or disruption of the posterior column.1,2
Evidence of a posterior column injury may include displaced fractures through the lamina, pedicles, or facet joints; widening of the interspinous distance; and edema in the posterior ligament complex on MRI. Unstable burst fractures are prone to further vertebral height collapse and bony retropulsion with normal axial loading. Severity of kyphosis, vertebral body compression, and the amount of canal compromise also play a role in surgical decision-making.1,2
This patient in this case has a posterior column involvement with a pedicle fracture and injury to the posterior ligament complex (with T12 spinous process fracture). He underwent a T11-L3 posterior instrumented fusion (2 levels above and below the fracture).
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Mikles MR, Stchur RP, Graziano GP. Posterior instrumentation for thoracolumbar fractures. J Am Acad Orthop Surg. 2004;12(6):424-35. doi:10.5435/00124635-200411000-00007
2. Woo JH, Lee HW, Choi HJ, Kwon YM. Are “unstable” burst fractures really unstable? J Korean Neurosurg Soc. 2021;64(6):944-949. doi:10.3340/jkns.2021.0080