Bilateral hypoglossal nerve damage due to the use of the harmonic focus scalpel

We describe the case of a 68-year-old man who presented with an anterior floor of mouth squamous cell carcinoma and underwent bilateral neck dissection. Subsequently, the patient developed permanent bilateral hypoglossal palsies, causing significant dysphagia, dysarthria and breathing difficulties. Hypoglossal nerve damage from surgical causes is uncommon, occurring in only 0.42% of functional neck dissections. However, it is the bilateral and permanent features of this case which make it unique. This injury may have been caused by incorrect use of the Harmonic Focus scalpel. Therefore, we discuss the literature demonstrating that the Harmonic Focus scalpel causes more lateral thermal damage than alternative tools, and the widely accepted 3 mm safety limit is not enough to protect important surrounding structures. This case report aims to highlight the need for proper training and specific identification of the hypoglossal nerve to prevent this rare and debilitating complication occurring in future patients.