Mourad P D, Lazar D A, Curra F P, Mohr B C, Andrus K C, Avellino A M, McNutt L D, Crum L A, Kliot M
Applied Physics Laboratory, University of Washington, Seattle 98105, USA.
Neurosurgery. 2001 May;48(5):1136-40; discussion 1140-1. doi: 10.1097/00006123-200105000-00035.
Axonal injury in the peripheral nervous system is common, and often it is associated with severe long-term personal and societal costs. The objective of this study is to use an animal model to demonstrate that transcutaneous ultrasound can accelerate recovery from an axonotmetic injury.
The sciatic nerve of adult male Lewis rats was crushed in the right midthigh to cause complete distal degeneration of axons yet maintain continuity of the nerve. Beginning 3 days after surgery, various transcutaneous ultrasound treatments or sham treatments were applied 3 days per week for 30 days to the crush site of rats that were randomly assigned to two groups. In the preliminary experiments, there were three animals in each ultrasound group and two control animals. In the final experiment, there were 22 animals in the ultrasound group and 20 animals in the control group. Recovery was assessed by use of a toe spread assay to quantify a return to normal foot function in the injured leg. Equipment included a hand-held transducer that emitted continuous-wave ultrasound. The most successful ultrasound protocol had a spatial peak, time-averaged intensity of 0.25 W/cm2 operated at 2.25 MHz for 1 minute per application.
Rats subjected to the most successful ultrasound protocol showed a statistically significant acceleration of foot function recovery starting 14 days after injury versus 18 days for the control group. Full recovery by the ultrasound group occurred before full recovery by the control group.
Transcutaneous ultrasound applied to an animal model of axonotmetic injury accelerated recovery. Future studies should focus on identification of the mechanism(s) by which ultrasound creates this effect, as a prelude to optimization of the protocol, demonstration of its safety, and its eventual application to humans.
周围神经系统的轴突损伤很常见，且往往会带来严重的长期个人和社会成本。本研究的目的是使用动物模型来证明经皮超声可加速轴突断裂损伤的恢复。
成年雄性Lewis大鼠的坐骨神经在右大腿中部被挤压，导致轴突完全远端变性，但神经保持连续性。术后3天开始，将各种经皮超声治疗或假治疗每周3天应用于随机分为两组的大鼠的挤压部位，持续30天。在初步实验中，每个超声组有3只动物，两个对照组各有2只动物。在最终实验中，超声组有22只动物，对照组有20只动物。通过使用趾展试验评估恢复情况，以量化受伤腿部恢复正常足部功能的程度。设备包括一个发射连续波超声的手持式换能器。最成功的超声方案是空间峰值、时间平均强度为0.25W/cm²，以2.25MHz运行，每次应用1分钟。
采用最成功超声方案的大鼠在受伤后14天开始显示出足部功能恢复的统计学显著加速，而对照组为18天。超声组在对照组完全恢复之前就实现了完全恢复。
应用于轴突断裂损伤动物模型的经皮超声加速了恢复。未来的研究应集中于确定超声产生这种效果的机制，以此作为优化方案、证明其安全性并最终应用于人类的前奏。
