Several techniques have been reported for smile restoration in patients with facial paralysis. When options in which a nerve other than the contralateral facial nerve is used, such as free muscle transfer with coaptation to the masseter nerve and lengthening temporalis myoplasty (LTM), the majority of these subjects can achieve a spontaneous smile without biting. The plasticity of the cerebral cortex, as well as the relative proximity of the motor centers of the smiling and chewing muscles have been considered; however, the mechanism behind this spontaneity is not well established. The aim of this study was to confirm the manifestation of spontaneity in patients who underwent LTM.
The study included 13 patients aged 12 to 74 years (mean 51.3 years), comprising 6 males and 7 females. All 13 temporalis transfer patients developed voluntary movement within 6 weeks, and 7 patients (54%) learned to smile without biting. Age affected the manifestation of spontaneous smiling (p=0.007). Neither gender nor duration of facial paralysis before the operation significantly affected spontaneity; however, females developed spontaneous smile more often than males.
