Associated lumbosacral junction injuries (LSJIs) in pelvic fractures.

Objective: To study lumbosacral junction injuries (LSJIs) associated with displaced sacral fractures.

Design: Prospective.

Setting: University hospital.

Patients: Eighty-nine patients with pelvic fractures.

Interventions: All patients underwent standard x-ray examination consisting of anteroposterior and inlet and outlet views of the injury. In 50 percent of the cases, oblique views were also obtained. Computed tomography (CT) scans were obtained for all vertically unstable lesions and for fifteen of the lateral compression lesions.

Main Outcome Measures: Pelvic fractures were classified according to Tile's classification. LSJIs associated with pelvic ring fractures were classified according to Isler.

Results: Lumbosacral junction injuries, including one bilateral lesion, were found in thirteen patients. One lesion was associated with a compression fracture, and the other twelve were associated with vertically unstable fractures. In one patient, a facet fracture was associated with a contralateral sacroiliac joint dislocation. A new type of LSJI was identified in three patients: it was characterized by disruption of the annulus fibrosus associated with rising of the hemipelvis and inclination of the L5 body.

Conclusion: Lumbosacral junction injuries should be suspected in cases of transforaminal sacral fracture, especially when these fractures are displaced. In such cases, we recommend that the lumbosacral junction be evaluated with appropriate CT scans.