In vivo characterisation of 3D intervertebral disc strains

下背痛是全球残疾的主要原因，估计每年花费NHS 5亿英镑。椎间盘退变和腰痛之间存在联系，这表明退变可能是一个促成因素。识别这种情况的患者并不简单，特别是当椎间盘退变而没有任何疼痛时。最初，腰痛患者采用保守治疗，但对于那些需要手术的患者，椎骨融合是最常见的手术，尽管越来越多的全或部分椎间盘置换技术被认为可以保留关节的运动。这些手术的结果相对较差，在10年内接受腰椎融合术的患者中，多达20%需要翻修手术。改善患者选择对于使用这些治疗获得良好的临床结果非常重要，但是目前可用的工具（通常是磁共振成像（MRI）或X射线）在做出临床决策之前提供的椎间盘功能信息很少。定量评估椎间盘内变形的能力将提供一种独特的工具，使治疗能够针对适当的患者，从而改善结局。最近的进展已经取得了在测量人类尸体标本的椎间盘变形相结合的技术称为数字体积相关（DVC）和MR图像捕获的高分辨率研究扫描仪（9.4T）。该技术的工作原理是通过获得两组图像的相同的标本，一个卸载，一个加载。然后在两组图像之间跟踪图像内的三维图案，使得可以计算变形和应变。这项研究的结果显示了巨大的潜力，但当该工具可以用于临床时，真实的突破将会到来，这是目前不可能的，因为研究MRI扫描仪的孔径小于10 cm。这项研究将在临床MRI扫描仪（即每家医院用于成像患者的扫描仪）中使用DVC，以创建一种测量椎间盘变形的非侵入性临床方法。这种新的诊断工具将允许更好的分层治疗。它还将为健康和退化椎间盘的复杂机制提供新的见解，这些信息将指导未来的手术治疗和医疗器械设计。

Low back pain is the leading cause of disability worldwide and is estimated to cost the NHS £500 million annually. A link has been found between degeneration of the intervertebral discs and low back pain, suggesting degeneration may be a contributing factor. Identifying patients where this is the case is not straight forward, particularly as it is possible to have degenerate discs without experiencing any pain at all.Initially, patients with low back pain are treated conservatively, but for those who require surgery, fusion of the vertebrae is the most common procedure, although increasingly total or partial disc replacement technologies are considered to preserve motion at the joint. Outcomes from these procedures are relatively poor, with revision surgeries required in as many as 20% of patients who undergo a lumbar fusion within 10 years. Improving patient selection is important for good clinical outcomes using these treatments, however the tools currently available (usually Magnetic Resonance Imaging (MRI) or X-ray) provide little information of how the disc is functioning before a clinical decision is made. The ability to assess quantitatively the deformations within discs would provide a unique tool to allow treatments to be targeted towards appropriate patients and therefore improve outcomes. Recent advances have been made in measuring disc deformations in human cadaveric specimens by combining a technique called Digital Volume Correlation (DVC) and MR images captured with a high-resolution research scanner (9.4T). The technique works by obtaining two sets of images of the same specimen, one unloaded, and one loaded. Three dimensional patterns within the images are then tracked between the two sets of images such that deformations and strains can be calculated. Results from this study show huge potential but a real breakthrough will come when the tool can be used clinically, this is not currently possible because the bore of research MRI scanners is less than 10cm in diameter.This study will utilise DVC in clinical MRI scanners (that is, scanners used in every hospital to image patients) to create a non-invasive clinical method of measuring intervertebral disc deformations. This novel diagnostic tool will allow better stratification in treatment. It will also provide fresh insight into the intricate mechanics of healthy and degenerate discs, information that will guide future surgical treatments and medical device designs.