Diagnostic value of various morphological features of horizontal and vertical laminar fractures for posterior ligamentous complex injury of the thoracolumbar spine as defined by MRI.

Abstract

OBJECTIVE\nTo determine the diagnostic value of the morphological features of horizontal laminar fracture (HLF) and vertical laminar fracture (VLF) for the diagnosis of posterior ligamentous complex (PLC) injury.\n\n\nMETHODS\nA retrospective review of 271 consecutive patients with acute thoracolumbar fractures presented to a level-1 trauma center between January 2014 and January 2021. Two reviewers evaluated CT and MRI images. VLFs were subclassified based on the length and depth of lamina involved, as follows: type 1-full-length complete laminar; type 2-full-length incomplete; type 3-partial-length complete or incomplete. HLFs were subclassified as follows: bilateral vs unilateral, displaced > 2 mm vs non-displaced, and lamina-only vs laminar and pedicle. We examined the diagnostic accuracy and the univariate and multivariate associations of laminar fracture subtypes with PLC injury as defined by black stripe discontinuity.\n\n\nRESULTS\nBilateral HLF, laminar and pedicle fracture, displaced HLF, and type-1 VLF yielded a high PPV for PLC injury (95, 91, 100%, 86%, respectively). Type 2 and 3 VLFs did not show significant univariate associations with PLC injury. Bilateral HLFs, laminar and pedicle fractures, and displaced HLF showed independent associations with PLC injury (AOR = 13.6, 8.4, 6, 10.3, respectively; P < 0.002). Type 1 VLF did not show a significant association with PLC (AOR = 10.3; P = 0.06).\n\n\nCONCLUSIONS\nBilateral, laminar and pedicle, and displaced HLFs, but not any VLF subtype, were independently associated with PLC injury. These findings may improve the reliability of PLC assessment by CT.