Normal and disrupted lumbar longitudinal ligaments: correlative MR and anatomic study.

Abstract

The posterior and anterior longitudinal ligaments of the lumbar spine appear on magnetic resonance (MR) images as thin lines of very low signal intensity in all spin-echo sequences. They cover the periphery of the outer fibers of the anulus fibrosus on sagittal images. The lumbar spine of 17 patients with 19 disk herniations was prospectively evaluated with MR imaging, and these findings were correlated with surgical findings. At surgery the posterior ligament was found to be disrupted in eight cases and intact in 11. Absence of a low-signal peripheral line around the herniated nucleus pulposus (HNP) was the most reliable sign of ligament rupture (no false-negative or false-positive findings). The peripheral line appeared to be interrupted in four cases, two of which were falsely positive. The two false-positive cases were related to a chemical shift artifact between epidural fat and the HNP. Presence of a normal and continuous peripheral line outlining the HNP excluded ligament disruption. The overall sensitivity for detecting disruption was 100%, and the specificity was 78%.

Comparison of MR Imaging Findings between Extraligamentous and Subligamentous Disk Herniations in the Lumbar Spine

“…At the level of the disk, PLL adheres to the posterior aspect of the disk and extends laterally beyond the foramen. 5 PLL is seen as a very low-signal-intensity line with 1 layer on all MR imaging pulse sequences. When we measured its thickness at the L5-S1 intervertebral disk level on T1-weighted sagittal images, its mean thickness was approximately 9.7 mm (range, 5.4 -11.5 mm).…”

“…5 In evaluating the PLL, the T1-weighted images were more accurate than the proton attenuationweighted and T2-weighted images. 5 There are only 2 reports of PLL integrity in the lumbar HIVD on MR images.…”

“…5 In evaluating the PLL, the T1-weighted images were more accurate than the proton attenuationweighted and T2-weighted images. 5 There are only 2 reports of PLL integrity in the lumbar HIVD on MR images. 5,6 Grenier et al, 5 in a prospective study of 17 patients with 19 lumbar disk herniations, reported 100% sensitivity and 78% specificity of MR imaging in detecting PLL disruption.…”

“…[1][2][3][4] However, to the best of our knowledge, there are only 2 reports on the integrity of the PLL in lumbar HIVD on MR images. 5,6 During microscopic diskectomy from a posterior approach, the integrity of the PLL can be easily determined on the operative field. In our institute, surgeons have described the integrity of PLL on surgical records after microdiskectomy as extraligamentous or subligamentous lumbar HIVD and have discussed these findings with radiologists during conferences.…”

Reprodutibilidade intra e interobservadores da classificação de Fujiwara para degeneração do ligamento interespinhoso por meio de ressonância magnética e relação entre as lesões degenerativas do disco intervertebral e do ligamento interespinhoso

“…Dessa forma, para um diagnóstico preciso, é fundamental empregar técnicas de imagem com boa resolução que permitam visualizar não só a morfologia da coluna, mas também as variações de cada doença, de traumas ou lesões degenerativas. A melhor técnica é a ressonância magnética, que analisa com precisão os tecidos moles, em especial os discos intervertebrais e os ligamentos espinhais [12][13][14][15][16][17] . As classificações das lesões discais têm sido muito utilizadas, pois permitem comparação de casuísticas e orientam condutas clínicas.…”