Salvage Dynamic Smile Reanimation with Reuse of the Masseteric Nerve

Purpose/Summary: Failed dynamic smile reanimation in patients with long standing facial paralysis has devastating psychosocial ramifications and poses significant challenges for the surgeon. There are multiple approaches to salvage dynamic function in patients with failed Free Functional Muscle Transfers (FFMT), however, there is a paucity of literature to help guide the surgeon in choosing a specific salvage modality. The objective of this study is to demonstrate the feasibility, describe the surgical technique, and assess the results of one such approach that had previously not been described – the reuse of the masseter nerve to re-innervate a new FFMT.

Methods: Patients who presented between 2007 and 2017 to a single center after previously failed dynamic smile reanimation using the masseteric nerve who underwent a salvage dynamic procedure involving re-use of the masseteric nerve were analyzed. Additionally, patient demographics, history of radiation or chemotherapy, surgical techniques, and objective measurements using the MEEI Facegram software were evaluated.

Results: The average duration of palsy was 6.2 years, and the average pre-operative HB score was 6. Etiologies of palsy included one patient with Bell’s palsy, two with parotid malignancies, and one with a CN7 schwannoma, with two patients requiring radiation preoperatively. Three patients failed to achieve any motion after one-stage reanimation with a FFMT to the masseteric nerve. The fourth patient initially achieved excursion, however, due to cancer recurrence and resection of FFMT, motion was subsequently lost. In one case, neurolysis of the masseter nerve at the area of previous coaptation led to motion 8 days after surgery, while the others achieved motion an average of 4 months after re-dissection of the masseter nerve and coapation to a new FFMT. Overall this series achieved 11.32 mm of smile excursion on the paralyzed side with a 1.3 mm philtral deviation correction in repose.

Conclusion: Dynamic smile restoration with FFMT in previously failed reanimation patients is feasible. Careful patient evaluation and clear understanding of previous procedures is key to success. Use of a new donor nerve, a previously used donor nerve, and rarely, neurolysis of a previous FFMT nerve coaptation, may all provide successful reanimation.

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