Bioengineering Department, Temple University, Philadelphia, Pennsylvania, United States of America.
School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, United States of America.
PLoS One. 2023 Aug 30;18(8):e0290718. doi: 10.1371/journal.pone.0290718. eCollection 2023.
Neonatal brachial plexus palsy (NBPP) results from over-stretching of the neonatal brachial plexus during complicated birthing scenarios. The lack of information on the biomechanical response of the neonatal brachial plexus complex when subjected to stretch limits our understanding of the NBPP injury mechanism. This study aims to fill that critical gap by using a neonatal piglet animal model and providing the in vivo biomechanical properties of the neonatal brachial plexus complex when subjected to stretch. Forty-seven brachial plexus levels (identified by the four brachial plexus terminal nerve branches namely musculocutaneous, median, ulnar, and radial), obtained from 16 neonatal Yorkshire piglets (3-5 days old), were subjected to stretch-induced failure. The average maximum load and corresponding strain were reported to be 16.6 ± 1.3 N and 36.1 ± 1.6%, respectively. Maximum loads reported at the musculocutaneous level were significantly lower than the median and radial levels. No differences in strains at failure were reported at all four tested levels. Proximal or distal failure locations were reported in 83% of the tests with 17% mid-length ruptures that were primarily reported at the bifurcation of the median and ulnar brachial plexus levels. Histological studies reported an overall loss of wavy pattern of the nerve fibers, an increase in nerve spacing, fiber disruptions, and blood vessel ruptures in the stretched tissue. This in vivo piglet animal study offers insight into the NBPP mechanism by reporting biomechanical, injury location, and structural damage responses in neonatal brachial plexus when subjected to stretch.
新生儿臂丛神经麻痹（NBPP）是由于复杂分娩情况下新生儿臂丛神经过度拉伸所致。由于缺乏关于新生儿臂丛神经复合体在拉伸时的生物力学反应的信息，限制了我们对 NBPP 损伤机制的理解。本研究旨在通过使用新生仔猪动物模型来填补这一关键空白，并提供新生儿臂丛神经复合体在拉伸时的体内生物力学特性。从 16 只新生约克夏仔猪（3-5 天大）中获得了 47 个臂丛神经水平（通过四个臂丛神经终末神经分支即肌皮、正中、尺侧和桡侧来识别），这些水平都经历了拉伸诱导的失效。报告的平均最大载荷和相应应变分别为 16.6 ± 1.3 N 和 36.1 ± 1.6%。报告的肌皮水平的最大载荷明显低于正中神经和桡神经水平。在所有四个测试水平上，在失效时的应变没有差异。83%的测试报告了近端或远端失效位置，17%的测试报告了中长度断裂，主要发生在正中神经和尺神经臂丛水平的分叉处。组织学研究报告说，拉伸组织中的神经纤维的波浪状模式总体丢失，神经间距增加，纤维中断和血管破裂。这项体内仔猪动物研究通过报告在拉伸时新生儿臂丛神经的生物力学、损伤位置和结构损伤反应，为 NBPP 机制提供了深入了解。
