Morphological changes elicited in skeletal muscle by a Nd: YAG laser scalpel and electrocautery during surgical reduction of the human tongue

Summary A Nd:YAG laser scalpel was used for the surgical reduction of a human hyperplastic tongue. This instrument combines a fine cutting precision with haemostatic properties, whereby loss of blood is minimized and the surgeon's field of view unimpeded by flooding from the damaged capillary bed. The coagulative properties of Nd:YAG laser light are, however, insufficient to effect blood flow stasis in larger calibre vessels (arteries > 2 mm; veins > 3–5 mm), such as those located at the base of the tongue. For this purpose, bipolar diathermy (electrocautery) was employed. The ultrastructural changes incurred by skeletal muscle fibres using these two ‘heat’ sources were compared. The damage profile elicited using each modality was similar: coagulation of myofilamentous proteins leads to destruction of fibrillar architecture with concomitant loss of periodic banding; on moving away from the wound margin, characteristic features are gradually restored. As the severity of these heat-induced effects decreases, there is a corresponding increase in superimposed dislocation and tearing phenomena induced by post-treatment swelling.