Marginal mandibular nerve injury during neck dissection of level IIa, and the influence of different types of dissection: diathermy versus cold knife

Introduction: Postoperative injury of the marginal mandibular branch of the facial nerve is considered a complication in neck dissection and can be related to different factors including traction, devascularisation or conduction block due to diathermy. Material and Methods: A prospective, crossover study including patients treated via bilateral selective neck dissection level IIa during a 12-month period, was performed to evaluate efficacy of the Hayes-Martin manoeuvre to prevent nerve injury during use of cold or monopolar diathermy dissection. Results: 20 patients met the inclusion criteria (40 neck dissections). Just one case of right temporal MMN weakness in the postoperative period was observed (1/40 = 2.5%). There were no cases of permanent marginal mandibular nerve weakness when using the Hayes-Martin manoeuvre. Conclusion: he Hayes-Martin manoeuvre is a safe method to preserve MMN during neck dissection level IIa, regardless of the type of dissection.