Transmission electron microscopy study of acute laser welds in dura mater and peripheral nerves

Abstract

In order to elucidate the mechanism of laser tissue welding, transmission electron microscopy (TEM) was used to investigate the ultrastructural changes of dura mater and peripheral nerves after CO2 laser welding. Dura mater and the epineurium of peripheral nerves were welded with a CO2 laser, both with and without the additional use of a protein solder (egg white). The specimens were immediately examined using TEM. It appeared that the tissues underwent specific alterations following laser welding and that three different welds could be distinguished: (1) welds in which collagen-to-collagen bonding occurs; (2) welds in which tissue debris forms a coagulated mass between the tissue interfaces; and (3) welds in which coagulated solder is melted on and between the collagen fibrils, forming a solid bridge between the tissue edges. These three different mechanisms have their own implications for pre-clinical and clinical practice.