Bell's palsy is defined as facial nerve weakness, usually on one side, for which there is no known cause. The facial nerve is responsible for controlling the muscles of facial expression, including the muscles that open the eyes and move the lips. A person with Bell's palsy typically has an asymmetrical smile because the side with the facial nerve weakness is unable to move the lips the same way as the unaffected side.
Surgical Suspension
One problem that a person with Bell's palsy develops is that he is unable to elevate the corner of his mouth to form a smile. Surgical procedures exist that place a sling under the skin to suspend the corner of the mouth affected by Bell's palsy in an elevated position. The sling can be connected to a muscle or bone on the affected side. When the person smiles, the opposite side comes up and the smile looks even. Surgeons can use tissue from other parts of the body or synthetic materials to form the sling.
Facial Reanimation
Facial reanimation techniques move muscle and nerve from another part of the body and attach the two in such a way that the person with Bell's palsy is able to control how her lip moves. The nerve is connected to a functional part of the facial nerve, and the muscle is connected to the corner of the mouth, so that when the nerve tells it to contract, it can elevate the corner of the mouth. The procedure is complicated, and requires multiple steps and considerable recovery time. But when successful, it allows a person to control the movement of that part of her face.
Nerve Grafts
Several different nerve grafts have been attempted to restore motion of the lips in order to correct the crooked smile in patients with Bell's palsy. Surgeons usually use sensory nerves from other parts of the body as the nerve grafts. The nerve typically is connected to the functional facial nerve on the opposite side of the face. The other end is connected to the muscle that elevates the corner of the mouth on the Bell's palsy side.
References
- "Clinical Pediatrics"; Facial Nerve Palsy in the Pediatric Population; Josef Shargorodsky; May 2010
- "Clinical and Experimental Otolaryngology"; Surgical Treatment of Facial Paralysis; Ritvik Mehta; March 2009
