Facial reanimation using free partial latissimus dorsi muscle transfer: single versus dual innervation method, a...

Though dual innervation method has emerged in single-stage functional latissimus dorsi (LD) muscle transfer for smile reanimation, its advantages over the single innervation technique remain controversial, particularly regarding spontaneous smiling and long-term functional outcomes.

To systematically analyze functional recovery, smile spontaneity, and long-term outcomes in facial reanimation using Free Partial Latissimus Dorsi Muscle Transfer (Partial LD transfer), comparing single- versus dual-innervation techniques.

A systematic literature search was conducted following PRISMA guidelines, identifying studies comparing single versus dual innervation methods for free partial latissimus dorsi muscle transfer in facial reanimation. Inclusion criteria were retrospective studies evaluating smile spontaneity, functional outcomes, and donor-site morbidity in patients with unilateral facial paralysis.

Of the 257 potential articles assessed, 15 studies, including 304 patients with long-standing unilateral facial paralysis met the inclusion criteria. Patients receiving single innervation predominantly developed voluntary smiles; however, spontaneous smiles were rarely achieved (range: 0%-10%). In contrast, the dual innervation group consistently showed higher rates of spontaneous smiles (range: 23%-100%), suggesting a better profile compared to single innervation. Dual innervation was also associated with better smile excursion and natural smile restoration.

The dual innervation technique results in superior spontaneous smile recovery compared to single innervation, providing better functional outcomes in facial reanimation for patients with long-standing facial paralysis. However, further prospective, comparative studies using standardized outcome measures are needed to clearly define the magnitude of these differences.