Significance of cell size and tissue structure in electrical trauma

High-voltage electrical trauma frequently leads to extensive and selective destruction of muscle and nerve tissue. In this paper, the mechanism of plasma membrane disruption due to the large transmembrane potentials imposed during electrical trauma is used to explain the particular susceptibility of muscle and nerve cells to damage. It is proposed that this vulnerability is partially due to the relatively large size of these cells. A distributed-parameter electric cable model of an elongated cell is used to examine the alteration of the transmembrane potential caused by a 60 Hz electric field applied parallel to the long axis of the cell. The maximum predicted transmembrane potential occurs at the ends of the cell and is strongly cell-size dependent. Theories are discussed which illustrate how this could explain the predisposition of skeletal muscle to cell membrane breakdown and rupture. The predicted effect of either close-neighboring cells in a tissue or cell contact with cortical bone is even greater induced transmembrane potentials and increased probability of rupture. This is the first hypothesis which explains the clinically-observed pattern of tissue damage resulting from electrical trauma.