Delayed repair of facial nerve trauma: an experimental study in guinea pigs.

CONCLUSION

The curative effect in the group where facial-facial anastomosis (FFA) was delayed for 7 days was similar to that in the immediate FFA group and had a better repair within 60 days.

OBJECTIVE

Due to the uncertainty about optimal timing of delayed facial nerve repair, we designed an experimental study in guinea pigs to find out the cut-off duration for delayed nerve repair.

METHODS

In this study, 64 male guinea pigs were randomly divided into 8 groups: normal, immediate FFA, and delayed FFA for 7, 14, 21, 30, 60, and 90 days (n = 6). Two months after suture of the nerves, the passing rate of myelinated fibers growing from the proximal to the distal stumps was calculated.

RESULTS

The passing rates of myelinated fibers in the groups with immediate FFA and FFA delayed for 7 days were significantly higher than those in other delayed FFA groups and the difference was statistically significant (p < 0.05), whereas the passing rates of the groups where FFA was delayed for 60 and 90 days were apparently lower than those of the immediate FFA and other delayed FFA groups. Under the electron microscope, regenerated fibers of the groups with immediate FFA and FFA delayed for 7 days were very similar to the normal myelinated fibers.