Free-flap surgery with double innervation for smiling restoration in long standing facial paralysis: a literature review.

Purpose: Currently, free-flap surgery with double innervation is considered a reliable and effective treatment in case of long standing facial paralysis. This study aimed to provide a current review of the literature (the "current state of the art") on lower third of the facial reanimation in restoring the voluntary and spontaneous smile in adult population using dual innervation free flap surgery.

Methods: We conducted a comprehensive literature review of all relevant papers by searching the electronic databases MEDLINE, Embase, Scopus, and the Cochrane Library.

Results: We included 12 retrospective studies involving 147 patients, five of which used the latissimus dorsi double innervation technique (42 patients) and seven of which investigated double innervation with a gracilis free flap (105 patients). In this review, we summarised the available data on smile recovery after free flap double innervation surgery. In half of the included studies, smiling was completely recovered.

Conclusions: Our study confirms that free flap surgery with dual innervation for long-term paralysis of the lower third of the face can guarantee comparable results using latissimus dorsi or gracilis free flaps. The best option depends on the case, taking into account the surgeon's skills and experience, as well as the patient's wishes and expectations.