A new medical procedure is literally giving people suffering from facial paralysis a reason to smile again.

Reconstructive surgeons at the Johns Hopkins University School of Medicine in Baltimore have developed a medical procedure called temporalis tendon transfer therapy that uses the muscle used for chewing to address the physical and emotional impact of facial paralysis.

The results are published in the July/August issue of Archives of Facial Plastic Surgery and they represent a breakthrough for reconstructive medicine.

"What we basically do with this procedure is we reroute a muscle that is typically used for chewing. We disconnect it from the jaw and we connect it to the muscles around the mouth to achieve two goals: one being to improve symmetry of the face, the other to return the ability to smile," said Dr. Patrick Byrne who leads the team at Johns Hopkins.

Byrne said the technique is relatively simple to do and is minimally invasive. While the procedure does not fully restore facial muscle function, patients are able to regain a range of motion and the ability to smile again through physical therapy.

Before the development of the temporalis tendon transfer surgery procedure, the approach to addressing facial paralysis used a different part of the same muscle, but the procedure often left patients with a facial deformity.

Facial paralysis is the loss of voluntary muscle movement that occurs primarily on one side of the face and can be caused by stroke, brain tumours and a condition called Bell's palsy.

As well as a highly visible physical improvement, the benefits of temporalis tendon transfer therapy can significantly impact the emotional well-being of an individual who undergoes the procedure.

"The fascinating thing about the face is that we all know that our emotions are expressed through our face," Byrne said.

"What is equally true is that the expression we have on our face affects our emotions. If you can't smile people tend to be depressed and when they can smile their mood changes and this is pretty well documented."