Lim Amanda, Protsenko Dmitry E, Wong Brian J F
Department of Biomedical Engineering, The Beckman Laser Institute and Medical Clinic, University of California, Irvine, Irvine, CA 92697, USA.
J Biomech Eng. 2011 Sep;133(9):094502. doi: 10.1115/1.4004916.
Transforming decades' old methodology, electromechanical reshaping (EMR) may someday replace traditionally destructive surgical techniques with a less invasive means of cartilage reshaping for reconstructive and esthetic facial surgery. Electromechanical reshaping is essentially accomplished through the application of voltage to a mechanically deformed cartilage specimen. While the capacity of the method for effective reshaping has been consistently shown, its associated effects on cartilage mechanical properties are not fully comprehended. To begin to explore the mechanical effect of EMR on cartilage, the tangent moduli of EMR-treated rabbit septal and auricular cartilage were calculated and compared to matched control values. Between the two main EMR parameters, voltage and application time, the former was varied from 2-8 V and the latter held constant at 2 min for septal cartilage, 3 min for auricular cartilage. Flat platinum electrodes were used to apply voltage, maintaining the flatness of the specimens for more precise mechanical testing through a uniaxial tension test of constant strain rate 0.01 mm/s. Above 2 V, both septal and auricular cartilage demonstrated a slight reduction in stiffness, quantified by the tangent modulus. A thermal effect was observed above 5 V, a newly identified EMR application threshold to avoid the dangers associated with thermoforming cartilage. Optimizing EMR application parameters and understanding various side effects bridge the gap between EMR laboratory research and clinical use, and the knowledge acquired through this mechanical study may be one additional support for that bridge.
机电重塑（EMR）改变了数十年的旧方法，有朝一日可能会用一种侵入性较小的软骨重塑方法取代传统的破坏性手术技术，用于面部整形和美容手术。机电重塑本质上是通过对机械变形的软骨标本施加电压来完成的。虽然该方法有效重塑的能力一直得到证实，但其对软骨力学性能的相关影响尚未完全了解。为了开始探索EMR对软骨的力学影响，计算了经EMR处理的兔鼻中隔软骨和耳廓软骨的切线模量，并与匹配的对照值进行比较。在两个主要的EMR参数，即电压和施加时间之间，前者在2 - 8V之间变化，后者对于鼻中隔软骨保持恒定在2分钟，对于耳廓软骨保持恒定在3分钟。使用扁平铂电极施加电压，通过0.01mm/s恒定应变率的单轴拉伸试验保持标本的平整度，以便进行更精确的力学测试。在2V以上，鼻中隔软骨和耳廓软骨的刚度都略有降低，用切线模量来量化。在5V以上观察到热效应，这是一个新确定的EMR应用阈值，以避免与软骨热成型相关的危险。优化EMR应用参数并了解各种副作用弥合了EMR实验室研究与临床应用之间的差距，通过这项力学研究获得的知识可能是对这座桥梁的又一项支持。
