Deneuville Jean-Philippe, Yushchenko Maksym, Vendeuvre Tanguy, Germaneau Arnaud, Billot Maxime, Roulaud Manuel, Sarracanie Mathieu, Salameh Najat, Rigoard Philippe
PRISMATICS Lab (Predictive Research in Spine/Neuromodulation Management and Thoracic Innovation/Cardiac Surgery), Poitiers University Hospital, Poitiers, France.
Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Poitiers, France.
Front Bioeng Biotechnol. 2021 Jun 9;9:676003. doi: 10.3389/fbioe.2021.676003. eCollection 2021.
Low back pain is a dramatic burden worldwide. Discography studies have shown that 39% of chronic low back pain patients suffer from discogenic pain due to a radial fissure of intervertebral disc. This can have major implications in clinical therapeutic choices. The use of discography is restricted because of its invasiveness and interest in it remains low as it represents a static condition of the disc morphology. Magnetic Resonance Imaging (MRI) appears to be less invasive but does not describe the biomechanical dynamic behavior of the fissure. We aimed to seek a quantitative MRI protocol combined with sagittal loading to analyze the morphological and biomechanical changes of the intervertebral disc structure and stress distribution. Proof of concept. We designed a proof-of-concept ovine study including 3 different 3.0 T-MRI sequences (T-weighted, T and T mapping). We analyzed 3 different mechanical states (neutral, flexion and extension) on a fresh ovine spine specimen to characterize an intervertebral disc before and after puncturing the anterior part of the annulus fibrosus. We used a mark tracking method to calculate the bending angles and the axial displacements of the discal structures. In parallel, we created a finite element model to calculate the variation of the axial stress and the maximal intensity shear stress, extrapolated from our experimental boundary conditions. Thanks to an original combination of specific nuclear relaxation time quantifications (T, T) of the discal tissue, we characterized the nucleus movement/deformation into the fissure according to the synchronous mechanical load. This revealed a link between disc abnormality and spine segment range of motion capability. Our finite element model highlighted significant variations within the stress distribution between intact and damaged disc. Quantitative MRI appears to provide a new opportunity to characterize intra-discal structural morphology, lesions and stress changes under the influence of mechanical load. This preliminary work could have substantial implications for non-invasive disc exploration and could help to validate novel therapies for disc treatment.
腰痛是全球范围内的一个重大负担。椎间盘造影研究表明，39%的慢性腰痛患者因椎间盘放射状裂隙而患有椎间盘源性疼痛。这可能对临床治疗选择产生重大影响。由于椎间盘造影具有侵入性，其应用受到限制，而且人们对它的兴趣仍然较低，因为它代表的是椎间盘形态的静态状况。磁共振成像（MRI）似乎侵入性较小，但无法描述裂隙的生物力学动态行为。我们旨在寻求一种结合矢状面负荷的定量MRI方案，以分析椎间盘结构的形态学和生物力学变化以及应力分布。概念验证。我们设计了一项概念验证性绵羊研究，包括3种不同的3.0 T-MRI序列（T加权、T和T映射）。我们在一个新鲜的绵羊脊柱标本上分析了3种不同的力学状态（中立、屈曲和伸展），以表征在穿刺纤维环前部之前和之后的椎间盘。我们使用标记跟踪方法来计算椎间盘结构的弯曲角度和轴向位移。同时，我们创建了一个有限元模型，以计算从我们的实验边界条件推断出的轴向应力和最大强度剪应力的变化。由于对椎间盘组织的特定核弛豫时间定量（T、T）进行了原始组合，我们根据同步机械负荷表征了髓核在裂隙中的运动/变形。这揭示了椎间盘异常与脊柱节段运动能力范围之间的联系。我们的有限元模型突出了完整椎间盘和受损椎间盘之间应力分布的显著差异。定量MRI似乎为表征机械负荷影响下的椎间盘内结构形态、病变和应力变化提供了新机会。这项初步工作可能对无创椎间盘探查有重大影响，并有助于验证新型椎间盘治疗方法。
