May 31, 2018

Modifying a muscle transplant operation, surgeons at Johns Hopkins have been able to restore more natural-looking, even smiles to patients with one-sided facial paralysis resulting from stroke, brain surgery, Bell’s palsy or other conditions.

The traditional procedure for the problem transfers a section of gracilis muscle from the inner thigh to the face, but because there are so many muscles involved in smiling, it results in what plastic surgeon Kofi Boahene calls a “Mona Lisa” smile—a social smile like the subject of Leonardo da Vinci’s painting that, while symmetric, has little movement or a display of teeth.

Boahene and colleagues developed a multivector gracilis muscle flap, aiming to replace as many muscles as possible to recreate normalcy. First, they study a patient’s face, noting the angle of the smile on the nonparalyzed side, how many teeth show, and the drape of the lips, studying the vectors needed to create a fuller smile.

During the four-to-six-hour procedure, surgeons take a 3-4 cm by 10-11 cm section of gracilis muscle and tease it apart into two to three smaller strips. They lift the skin of the face and cheek from the front of the ear to the lip, and insert the muscle in two to three directions at the corner of the mouth or upper lip to the cheek and eyelid. The muscle is then connected to blood vessels, and sutures are placed around the lip in the vectors surgeons want the muscles to move. Once the positioning is good and muscle tension is adjusted, surgeons place additional sutures to hold the transplanted muscle in place and, under the microscope, connect blood vessels in the muscle to blood vessels in the neck, then connect nerves to the muscle that will stimulate it to move. Incisions are hidden in the hairline or the crease next to the ear. 

Most patients stay in the hospital for three days following surgery, and start to gain function in the transplanted muscle within four months. Over the next year, the brain rewires the new muscle to make it part of the face, and movement becomes more sophisticated, Boahene says.

A description of the procedure in the first 12 patients was published recently in JAMA Facial Plastic Surgery. On average, patients show an extra three teeth when smiling on the newly functional side of the face. The amount of gum exposed during smiling increases and differences between the corners of each side of the mouth decreases. They have since performed the procedure on more than 50 patients.

“When someone’s face is paralyzed, they look depressed,” Boahene says. “They withdraw from society, cover their mouth when they talk and you can see their confidence is gone. When they come in and say they feel a twitch in the transplanted muscle, their whole body language changes. They smile, and it makes me smile.”

Nearly every patient, whether they have experienced paralysis short-term or long-term, is a candidate, Boahene says: “I tell physicians if their patient has paralysis and is not recovering within six months to come and see us. In almost every situation, there’s an improvement we can achieve.”

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