Background: Patients with facial paralysis experience
functional and cosmetic problems related to facial muscles
inactivity. Free micro neurovascular functional muscle transfer
offers the best prospect for restoring both voluntary and
emotional facial expressions. The transferred muscle replaces
some of the paralyzed muscles, mainly the lip elevators. If
the lip depressors are not replaced, asymmetry of the mouth
persists. This study investigates splitting of the latissimus
dorsi muscle to replace lip elevators and depressors in different
vectors to reanimate the smile.
Methods: We studied 10 latissimus dorsi muscle specimens
obtained from five fresh cadavers. Intramuscular dissection
for the branches of the nerve and blood vessels was performed.
A radio-opaque lead oxide mixture was injected to obtain
radiograms. Splitting of the muscle was done parallel to the
muscle fibers and neurovascular branches. The nerve pedicle
was split into two fascicles by intrafascicular dissection along
its whole length.
Results: We split all muscle specimens into neurologically
independent segments with each segment containing one of
the main branches of the neurovascular bundle. Splitting of
the whole length of the thoracodorsal nerve into two branches
was performed in all specimens.
Conclusions: This study suggests that the latissimus dorsi
muscle is suitable for segmental splitting into completely
independent muscle slips that can be rotated into entirely
different vectors to reanimate the smile, including both upward
and downward pulls on the oral commissure.