Anatomical variations and functional outcomes of the marginal mandibular nerve in neck dissection for head and neck malignancies: A prospective study.

BACKGROUND

The marginal mandibular nerve (MMN) is vulnerable during neck dissection for head and neck cancer. This study documents its anatomical variations and evaluates postoperative functional and quality-of-life outcomes.

METHODS

A prospective observational study was conducted with fifty-one patients undergoing neck dissection for primary head and neck malignancy. Preoperative and postoperative assessments carried out at 1 and 3 months after surgery included clinical evaluation of lip symmetry, electromyography (EMG) of the depressor anguli oris, and quality-of-life (QoL) using FACT-H&N and Distress Inventory for Cancer (DIC) version-2 questionnaire. Intraoperative MMN anatomy was systematically recorded.

RESULTS

MMN was identified in all the 51 neck dissections carried out. Mean number of branches was 1.05 ± 0.23, and mean distance from the mandibular border was 1.67 mm. Lip asymmetry was observed in over 50% of patients at 1 month, decreasing to 20% at 3 months. EMG showed complete denervation in 13 patients at 1 month, which continued till 3 months with no recovery, the branch was sacrificed in 11 of these for oncological clearance. FACT-H&N scores and DIC2 scores improved at 6 months follow-up.

CONCLUSION

Meticulous identification and preservation of the MMN minimize transient dysfunction, with most patients achieving functional recovery and QOL improvement by 3 months.