Kerensky Max J, Paul Abhijit, Routkevitch Denis, Hersh Andrew M, Kempski Leadingham Kelley M, Davidar A Daniel, Judy Brendan F, Punnoose Joshua, Williams Autumn, Kumar Avisha, Lehner Kurt, Smith Beth, Son Jennifer K, Azadi Javad R, Shekhar Himanshu, Mercado-Shekhar Karla P, Thakor Nitish V, Theodore Nicholas, Manbachi Amir
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
HEPIUS Innovation Laboratory, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Commun Med (Lond). 2024 Jan 5;4(1):4. doi: 10.1038/s43856-023-00430-6.
Tension in the spinal cord is a trademark of tethered cord syndrome. Unfortunately, existing tests cannot quantify tension across the bulk of the cord, making the diagnostic evaluation of stretch ambiguous. A potential non-destructive metric for spinal cord tension is ultrasound-derived shear wave velocity (SWV). The velocity is sensitive to tissue elasticity and boundary conditions including strain. We use the term Ultrasound Tensography to describe the acoustic evaluation of tension with SWV.
Our solution Tethered cord Assessment with Ultrasound Tensography (TAUT) was utilized in three sub-studies: finite element simulations, a cadaveric benchtop validation, and a neurosurgical case series. The simulation computed SWV for given tensile forces. The cadaveric model with induced tension validated the SWV-tension relationship. Lastly, SWV was measured intraoperatively in patients diagnosed with tethered cords who underwent treatment (spinal column shortening). The surgery alleviates tension by decreasing the vertebral column length.
Here we observe a strong linear relationship between tension and squared SWV across the preclinical sub-studies. Higher tension induces faster shear waves in the simulation (R = 0.984) and cadaveric (R = 0.951) models. The SWV decreases in all neurosurgical procedures (p < 0.001). Moreover, TAUT has a c-statistic of 0.962 (0.92-1.00), detecting all tethered cords.
This study presents a physical, clinical metric of spinal cord tension. Strong agreement among computational, cadaveric, and clinical studies demonstrates the utility of ultrasound-induced SWV for quantitative intraoperative feedback. This technology is positioned to enhance tethered cord diagnosis, treatment, and postoperative monitoring as it differentiates stretched from healthy cords.
脊髓张力是脊髓拴系综合征的一个特征。不幸的是，现有检测方法无法量化脊髓整体的张力，使得对拉伸的诊断评估不明确。一种潜在的用于评估脊髓张力的非侵入性指标是超声衍生剪切波速度（SWV）。该速度对包括应变在内的组织弹性和边界条件敏感。我们使用术语“超声张力成像”来描述利用SWV对张力进行的声学评估。
我们的解决方案“超声张力成像脊髓拴系评估（TAUT）”用于三项子研究：有限元模拟、尸体实验台验证和神经外科病例系列研究。模拟计算给定拉力下的SWV。诱导产生张力的尸体模型验证了SWV与张力的关系。最后，在接受治疗（脊柱缩短）的脊髓拴系综合征患者术中测量SWV。手术通过缩短脊柱长度来减轻张力。
在临床前的子研究中，我们观察到张力与SWV平方之间存在很强的线性关系。在模拟模型（R = 0.984）和尸体模型（R = 0.951）中，更高的张力会诱导更快的剪切波。在所有神经外科手术中SWV均降低（p < 0.001）。此外，TAUT的c统计量为0.962（0.92 - 1.00），能检测出所有脊髓拴系情况。
本研究提出了一种评估脊髓张力的物理性临床指标。计算研究、尸体实验研究和临床研究之间的高度一致性证明了超声诱导SWV用于术中定量反馈的实用性。这项技术能够增强脊髓拴系的诊断、治疗及术后监测，因为它能区分拉伸的脊髓和健康的脊髓。
