Muscle Transplant Reanimates Smile Following Facial Paralysis

By modifying the gracilis muscle flap, authentic facial expressions of joy can be restored to patients with one-sided facial muscle paralysis, according to a new study.

Researchers at Johns Hopkins University School of Medicine (JHU-SOM; Baltimore, MD, USA), Ohio State University (OSU, Columbus, USA), and other institutions conducted a prospective cohort study in 12 patients with complete facial paralysis in order to determine if modifying the gracilis flap as a multivector flap with two or more paddles is an effective way of improving all components of the smile display zone, and has the potential for restoring a Duchene-type smile in such patients.

The modified procedure uses gracilis muscles from the thigh placed in two directions (and sometimes three) at the corner of the mouth or the upper lip to the cheek and eyelid so as to recreate an authentic smile that improves dental display, smile width, and correction of paralytic labial drape. The procedure also involves rerouting blood vessels and nerves to the transplanted tissue from the non-paralyzed side of the face. The premise is that when the nerves on the nonparalyzed side send a signal for the muscle to contract, forming a smile, they do so for the paralyzed side of the face as well.

The results revealed functional muscle recovery in all cases. An extra three teeth when smiling on the newly functional side of their face were revealed, with an increase in gingival scaffold exposure from 31.5 millimeters before surgery to 43.7 millimeters after surgery. In addition, wrinkling around the eyes when smiling was observed in four of the 12 people after surgery, and asymmetry was reduced from an average of 9.1 millimeters to 4.5 millimeters, making the smiles more even. The study was published on March 22, 2018, in JAMA Facial Plastic Surgery.

“Previously, the best we could hope for most of the time with surgery was a smirk where just the corners of the mouth upturn in a smile, like the one Mona Lisa has in DaVinci's famous painting. Now we're able to really restore a true smile,” said lead author Kofi Boahene, MD, of JHU-SOM. “In the past, we were restoring fake smiles, and now our patients' new smiles are so contagious that you can't help but smile back.”

Facial nerve paralysis is characterized by unilateral facial weakness, with other symptoms including loss of taste, hyperacusis, and decreased salivation and tear secretion. Other signs may be linked to the cause of the paralysis, such as vesicles in the ear, which may occur if the facial palsy is due to shingles. Causes included birth defects, stroke, trauma, tumors, or Bell's palsy.

Related Links:
Johns Hopkins University School of Medicine
Ohio State University