Prospective cohort study.
To study whether there is a sequential pattern in the posterior ligamentous complex (PLC) rupture caused by deforming traumatic forces by analyzing magnetic resonance (MR) images in a consecutive prospective cohort of patients with traumatic vertebral fracture.
PLC plays an important role in vertebral stability. However, the sequence in which the different components of the PLC tear, in the face of traumatic forces, has not been yet described.
Prospective study of 74 consecutive vertebral acute traumatic fractures analyzed using radiography and magnetic resonance imaging (MRI) (FS-T2-w/short-tau inversion-recovery [STIR] sequences). Fracture morphology was classified according to the AO classification. Integrity of each PLC component—facet capsules, interspinous ligament (ISL), supraspinous ligament (SSL), and ligamentum flavum (LF)—was assessed and classified as intact, edema, or disruption. ISL edema was further subdivided depending on the extension (>50%/<50%). We analyzed the association between MRI signal and the AO progressive scale of morphological damage.
AO type A1/A2 fractures associated with only facet distraction. A3 fractures showed additional ISL edema, usually less than 50%, with neither SSL nor LF disruption. Type B1 fractures associated with facet distraction, ISL edema or disruption, and low rate of SSL/LF disruptions; B2 fractures increased SS/LF disruption rates. Type C fractures associated with facet fracture or dislocation and ISL, SSL, or LF complete rupture. We found high association (P < 0.001) between AO progressive scale and MRI signal.
MRI analysis showed that posterior distraction forces begin in the facets and extend throughout the ISL, starting at its posterosuperior margin (finally disinserting the SSL superiorly) and traveling diagonally toward anteroinferior border, finally tearing the LF.
MR images correlated with AO progressive scale of morphological damage, which showed a progressive orderly rupture sequence among the different PLC components as traumatic forces increased.
A prospective cohort of acute traumatic fractures was studied by magnetic resonance imaging. Images show a progressive orderly rupture sequence among the different posterior ligamentous complex components as traumatic forces increase. Distraction begins at the facets, extends throughout the interspinous ligament, and ends up rupturing the supraspinous ligament and finally the ligamentum flavum.
From the Spine Unit, Department of Orthopaedic Surgery, Hospital Universitario de Getafe, Madrid, Spain
Address correspondence and reprint requests to Javier Pizones, MD, PhD, Department of Orthopaedic Surgery, Hospital de Getafe, Carretera de Toledo Km. 12.5, 28905 Madrid, Spain; E-mail: email@example.com
Acknowledgment date: July 7, 2011. First revision date: October 4, 2011. Second revision date: November 9, 2011. Acceptance date: November 12, 2011.
The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.
No funds were received in support of this work.
No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.