Many consider facial nerve monitoring compulsory in parotid surgery yet few do the same for the marginal mandibular nerve in a submandibular approach, even though the nerve is finer and more difficult to identify. Here a group map the nerve on the surface of the skin utilising transcutaneous stimulation, a technique commonly used by anaesthetists undertaking nerve blocks. The article reports that their transcutaneous mapping corresponds to the operative findings.
They have taken 40 patients and preoperatively mapped the course of the marginal mandibular nerve then utilised intraoperative nerve monitoring to locate the nerve and compare its position to that mapped transcutaneously.
They successfully mapped 39 out of 40 nerves. The literature reports marginal mandibular nerve injury rates of up to 17.5%. The technique described seems simple and potentially useful clinically. The variability of the marginal mandibular nerve proved a challenge and if mapping can reduce the rate of nerve injury in this cosmetically sensitive area this technique may be worth adopting.