Miller Mark Carl, Schimoler Patrick J, Shah Harsh, Kharlamov Alexander, Graham R David, Armstrong Carol, Wroblewski Andrew, Yin Yue, Tang Peter
Departments of Mechanical Engineering and Materials Science and Bioengineering, University of Pittsburgh, 633 Benedum Hall, Pittsburgh, PA, 15261, USA.
Allegheny Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, 15212, USA.
Ann Biomed Eng. 2025 Jul;53(7):1732-1739. doi: 10.1007/s10439-025-03733-y. Epub 2025 May 6.
Surgical interventions for ulnar neuropathy are typically identified as releases or decompressions. With the expectation that ulnar nerve strain contributes to cubital tunnel syndrome and with the basic hypothesis that nerve tension will most significantly increase in positions of highest elbow flexion, wrist extension, and classic sites of compression, we initiated a new experimental technique to quantify strain and tension in the ulnar nerve.
In five fresh-frozen cadaveric upper extremities from the spine to the wrist, we percutaneously placed small radiopaque spheres into the ulnar nerve using ultrasound guidance to allow tracking of ulnar nerve motion and elongation under fluoroscopy. This technique caused minimal disruption to the soft tissues tethering the nerve. In a custom jig, the forearm was fixed in space while varying elbow and wrist range of motion. After removal of the hand, we measured nerve motion and the tensions constraining the nerve using proportional techniques with application of loads at four standardized locations between the radiocarpal joint and elbow.
Means of all in situ tensions varied from 0.54 to 4.28 N. There were significant differences in these constraints tensions among the different elbow flexion angles (p = 0.020). There were differences in in situ tension at the sites of constraint but consistent strains across all four sites.
The fluoroscopic technique with percutaneous marker placement successfully allowed strain and tension measurements. The differences in tensions but consistent strains suggest that surgical repair with attention to the attachment of the nerve might restore native nerve gliding and mechanical behavior.
尺神经病变的外科手术干预通常被认定为松解或减压手术。鉴于尺神经牵张被认为会导致肘管综合征，且基于神经张力在最大程度屈肘、伸腕以及经典受压部位时会显著增加这一基本假设，我们开创了一种新的实验技术来量化尺神经中的应变和张力。
在5具从脊柱至腕部的新鲜冷冻尸体上肢中，我们在超声引导下经皮将不透射线的小珠置入尺神经，以便在荧光透视下追踪尺神经的运动和伸长情况。该技术对束缚神经的软组织造成的干扰极小。在一个定制夹具中，前臂在空间中固定，同时改变肘部和腕部的活动范围。在移除手部后，我们使用比例技术在桡腕关节和肘部之间的四个标准化位置施加负荷，测量神经运动和限制神经的张力。
所有原位张力的平均值在0.54至4.28牛之间。不同肘部屈曲角度之间的这些约束张力存在显著差异（p = 0.020）。约束部位的原位张力存在差异，但所有四个部位的应变一致。
经皮放置标志物的荧光透视技术成功实现了应变和张力测量。张力的差异但应变一致表明，关注神经附着情况的手术修复可能会恢复神经的自然滑动和力学行为。
