Assessment of injury to the posterior ligamentous complex in thoracolumbar spine trauma

Background contextPosterior ligamentous complex (PLC), consisting of supraspinous ligament (SSL), interspinous ligament (ISL), ligamentum flavum (LF), and the facet joint capsules is thought to contribute significantly to the stability of thoracolumbar spine. Currently, no consensus exists on radiographic imaging parameters that may indicate injury to the posterior ligamentous complex.PurposeTo identify imaging parameters that may suggest a disruption of the PLC of the thoracolumbar spine.Study desing/settingA survey analysis of members of the Spine Trauma Study Group.Patient sampleNone.Outcomes measuresCompilation of survey results.MethodsAn extensive review of the literature from 1949 to the present was performed to identify key radiographic elements that have been suggested as indicators of PLC injury. Twelve items identified as such were placed on a survey and sent to the members of the Spine Trauma Study Group. They were asked to rank the items from most important to least important, and the results were complied for analysis.ResultsTwenty-eight surveys were returned for final analysis. Fifty-percent (14/28) of the members ranked “vertebral body translation” on plain radiographs as the most important factor in determining disruption of PLC. Plain radiographic sings were ranked higher than computed tomography or magnetic resonance imaging indicators, and history of the mechanism ranked lowest. The members were also given freedom to add other criteria that they felt were important in determining PLC integrity. “Interspinous spacing 7 mm greater than that of level above or below on antero posterior plain X-rays” was the only new category that was suggested.ConclusionPlain radiographic findings were felt to be most helpful in determining PLC injury by the members of the Spine Trauma Study Group. Physical examination findings and history of the mechanism of injury were ranked lower than imaging studies. Future analysis should focus on indicators of PLC injury when plain radiographic findings are either subtle or not present.