Does the method of resection affect the margins of tumours in the oral cavity? Prospective controlled study in pigs.

It is important to obtain tumour-free resection margins in patients with oral cancer. Pathological processing is known to cause tissue to shrink, which affects the reported margins, and it is postulated that the method of resection also has an effect. We marked standardised simulated lesions on the tongues of 15 live anaesthetised pigs and divided each lesion into four equal sections. They were resected each with a margin of 10mm using cutting diathermy, coagulative diathermy, Harmonic scalpel, and a conventional scalpel. After processing, the excision margins were measured. With cutting diathermy and coagulative diathermy, shrinkage of the soft tissues was minimal relative to the margin of the simulated lesion compared with the Harmonic scalpel (p=0.001) and conventional scalpel (p=0.001). Cutting diathermy and coagulative diathermy caused significant thermal damage (p=0.001). The method of resection affects the surgical margin. Diathermy resulted in thermal injury and denaturing of the underlying muscle, but there was less tissue contraction than when the Harmonic scalpel and conventional scalpel were used. The ethics committee approved the study, which was undertaken in a registered European Scientific Institute in Hamburg.