Marginal mandibular nerve injury is a complication that causes an aesthetic deficit that has a great impact on the patient’s perception of appearance, inevitably influencing quality of life.^1,2The reason for this deficit is loss of innervation of depressor angulioris, depressor labii inferioris, mentalis, and orbicularis oris muscles, causing inability to move the lower lip downward or laterally.³ The consequent cosmetic deficit, manifesting lower lip asymmetry and imbalance, is especially noticeable when opening the mouth and is most obvious when the patient cries.^2,4Because the condition of the neck lymph nodes is the single most important prognostic factor in carcinoma of the upper digestive airways, neck dissection has become ordinary clinical practice in head and neck oncologic surgery.⁵

The main cause of nerve injury is that the marginal mandibular nerve has a highly variable anatomy that cannot ensure reliable anatomic landmarks.

Nerve integrity monitoring (NIM) is a technique that monitors muscle activity as a reflection of nerve function during surgery. The benefits of electromyographic monitoring for nerve preservation have been well established in many ear, nose, and throat (ENT) surgeries; however, its use is still debated in other procedures. The purpose of this study will be to assess the usefulness of NIM as an aid to reduce the incidence of marginal mandibular nerve paralysis after neck dissection, also to consider its possible impact on costs and surgical time.

In our institution , among 74 patients with stage T1/T2 per primum carcinoma tongue operated for per-oral wide local excision of tongue with unilateral neck dissection within January 2017 to June 2018, there is an incidence of around 58 % patients having temporary marginal paresis in the post operative period and on follow up of minimum 3 months and more, around 32 % are still having marginal nerve paresis i.e permanent nerve paresis