Mohs micrographic surgery (MMS) can cause nerve damage when performed near the temporal branch of the facial nerve, according to results of a recent study. In this study, researchers identified variables that appear associated with this risk in patients undergoing MMS for skin cancer in this area of the face. Results were reported in the journal Dermatologic Surgery.

“Any invasive procedure performed in the temporofrontal region of the face, including face/brow lifts and dissections in craniofacial and trauma surgery, puts the temporal nerve and its branches at risk of transection, trauma, ligation, and electrical injury,” the researchers explained in their report. MMS is often performed in this region of the face.

The study was a single-center, retrospective analysis of patient characteristics and outcomes of patients who underwent MMS from December 2010 to July 2018 in the area of the face where damage to the temporal nerve was a potential risk. The researchers based their analysis on data from electronic medical records.


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The study population included 616 patients who underwent MMS. Most of the patients (65.1%) had basal cell carcinoma, 34.1% had squamous cell carcinoma, and tumor type was listed as “other” in 0.8% of patients.

Postoperative temporal nerve dysfunction was reported in 28 patients (4.5%). Of those, nerve damage appeared to be associated with several factors. Immunosuppression (P =.0102), a higher histologic tumor risk (P <.0001), larger preoperative tumor size (P <.0001), larger postoperative tumor size (P <.0001), greater subclinical spread (P <.0001), and a greater number of MMS stages (P <.0001) were all associated with nerve damage. Age, tumor type, and tumor recurrence did not appear significantly associated with nerve damage.

The researchers also reported that tumor size, indicated by preoperative tumor size and postoperative defect size was most closely associated with temporal nerve damage. A preoperative tumor size of 3 cm or larger carried a 37.7-times greater odds of temporal nerve damage, and a postoperative defect size of 3 cm or larger carried a 40.7-times greater odds of this damage, when measuring size along the longest single dimension. However, no patients showed evidence of nerve damage with a postoperative defect size of less than 2 cm along the longest single dimension.

“To the best of the authors’ knowledge, this is the first study to characterize risk factors for temporal nerve damage from MMS, and the results will be helpful in optimizing patient expectations and outcomes after surgery in the temporofrontal region of the face,” the researchers wrote in their report.

Reference

Axibal EL, Fisher MH, Miller MD, Brown MR. Damage to the temporal branch of the facial nerve from Mohs micrographic surgery. Dermatol Surg. Published online September 13, 2022. doi:10.1097/DSS.0000000000003579