Damage to the Temporal Branch of the Facial Nerve From Mohs Micrographic Surgery

Background: The temporal branch of the facial nerve is at risk of damage during Mohs micrographic surgery (MMS). This complication leads to motor deficit in the ipsilateral upper face with resultant functional and cosmetic impairment.

Objective: To identify patient, tumor, and surgical risk factors associated with temporal nerve damage.

Materials and methods: A single-institution, retrospective review of MMS cases involving anatomic sites within the temporal nerve danger zone was performed. Risk factors were compared between cases with and without nerve damage.

Results: Of 616 cases within the danger zone, 28 (4.5%) had postoperative nerve dysfunction. Variables significantly associated with dysfunction included patient immunosuppression, tumor size, aggressive tumor histology, recurrent tumors, high degree of subclinical spread, and greater average number of Mohs stages. Preoperative tumor size and postoperative defect size of ≥3 cm resulted in a ×37 and ×40 increased odds of nerve damage, respectively. Sex, age, and basal versus squamous cell carcinoma were not significantly associated with temporal nerve damage. No patients with a postoperative defect size measuring <2 cm had nerve damage.

Conclusion: The overall risk of damage to the temporal nerve during MMS is low, but there are certain risk factors that warrant increased counseling about this potential complication.