Surgeons at Johns Hopkins University recently reported success in restoring the ability to smile in individuals living with partial facial muscle paralysis caused by congenital disabilities, stroke, tumors or Bell’s palsy, and patients aren’t the only ones smiling at the advancement.
“The smile is one of the most important facial expressions there is, and when people cannot smile, they are often viewed negatively by others,” said Dr. Gregory W. Chernoff, a triple-board-certified facial, plastic and reconstructive surgeon.
Prior attempts by Johns Hopkins and other surgeons used standard surgical protocols to treat patients with one-sided facial paralysis. These protocols involved transplanting muscle tissue from the thigh to the affected side of the face to pull that side up. The procedure left patients with a smirk similar to Leonardo DaVinci’s Mona Lisa and still unable to express joy.
The Johns Hopkins researchers modified the standard fix for treating patients with this form of facial paralysis by using the gracilis muscles of the thigh.
The gracilis muscle starts at the external point of the pubic bone and extends to the shinbone. The gracilis muscle is responsible for hip adduction, or moving the leg away from the body. It also assists in flexing the knee flexion.
The muscle was placed into two or three directions at the corner of the mouth or upper lip and connected to the cheek or eyelid to create a more natural smile.
Instead of just a slight smirk, the patients’ new smiles show teeth and gums on both sides of the face versus only one side.
Individuals living with one-sided facial paralysis often report feeling self-conscious about their image. They also often report feeling depressed and awkward.
“Aside from changing an individual’s appearance, one-sided facial paralysis can also cause physiological problems, such as drooling and problems blinking,” Chernoff said.
For the current study, the surgeons selected 10 women and two men between ages 20 and 64 who underwent the modified smile procedure between June 2015 and December 2016.
Before their procedures, the study authors videoed the patients and measured the angle, degree and type of smile on the unaffected side of each participant’s face.
During their smile-correction surgery, the surgeons placed the new muscles in positions that allowed them to pull up the lips to match the non-paralyzed side.
After the muscles were placed, the surgeons rerouted the blood vessels and nerves to the transplanted tissue from the non-paralyzed side of the face to bring nutrients and oxygen needed to sustain the muscles.
The procedure was done in this manner because the transplanted muscle needed signals from the nerves to contract and form the smile.
Four months after their surgical procedures, all of the participants had function in the transplanted tissue that allowed them to show three extra teeth when smiling, on average.
The amount of visible gum also increased from an average of 31.5 millimeters before their procedure to 43.7 millimeters after their surgery.
The Johns Hopkins researchers also noticed more creasing and wrinkling near the eyes when smiling in a third of the participants.
Smile asymmetry was reduced from 9.1 millimeters to 4.5 millimeters on the affected sides, which made the patients’ smiles more even and natural looking.
The Johns Hopkins researchers were excited about their success. So is Chernoff.
“Reconstructive surgery is a large part of what plastic surgeons do every day. Plastic surgery is not just about improving appearance; it is also about restoring function,” Chernoff said.
Johns Hopkins Medicine. “Surgeons transform static ‘Mona Lisa’ smiles to joyous ones.” ScienceDaily. ScienceDaily, 28 March 2018.