A comparison of commissure excursion following gracilis muscle transplantation for facial paralysis using a cross-face nerve graft versus the motor nerve to the masseter nerve.

BACKGROUND: The microneurovascular transfer of a free muscle transplant is the procedure of choice for facial animation in a child with facial paralysis. One of the critical factors of this procedure is the selection of a motor nerve to innervate the transplanted muscle.

METHODS: From 1989 to 1999, 166 free segmental gracilis muscle transfers were performed in 121 children for facial animation. The cross-face nerve graft was used in 70 procedures (cross-face nerve graft group) to innervate the muscle by branches of the seventh nerve for the normal side. The ipsilateral masseteric nerve was used in 94 procedures (50 patients, masseter group) and the ipsilateral accessory nerve was used in two procedures (one patient). To compare the operative procedures between the first two groups, all charts were reviewed. The extent of oral commissure movement was determined by measurements taken from the tragion to the oral commissure, both at rest and with full smile. In the cross-face nerve graft group (n = 20), the extents were measured on both the normal side and the reconstructed side; in the masseter group (n = 16), they were measured on the left and right sides.

RESULTS: No significant difference was found between the two groups (p < 0.05) for the mean age at the time of muscle transplantation, for the total operation time for muscle transplantation, and for the length of the muscle used or for the fraction of circumference of the segment of gracilis muscle used. Although the operative variables were similar between two groups, the muscle excursion differed. Excursion in the cross-face nerve graft group was less than that on the right (p = 0.0006) or left (p = 0.0000) in the masseter group. It was also less than on the normal side (p = 0.0000) of the cross-face nerve graft group. Also, there was no significant difference between the left and right sides within the masseter group (p < 0.05). Furthermore, the extent of oral commissure movement in the masseter group was similar to that of the normal side in the cross-face nerve graft group (p = 0.35, p = 0.61).

CONCLUSION: These results indicate that segmental gracilis muscle transplantation using the motor nerve to the masseter nerve for facial animation in children is a very reproducible operation and provides a commissure excursion in the range of normal.