Evolution of Triple Innervation Technique in the Treatment of Facial Paralysis

Background

The aim of this study is to compare the traditional triple innervation technique with a new version, designed to reduce eye-mouth synkinesis. To reduce unpleasant synkinesis, the authors proposed changing the connection between the masseteric nerve and the injured facial nerve, analyzing the outcome in terms of reduction of synkinesis and power of contraction of the mimic muscle. The traditional technique conveys the quantitative stimuli from the masseteric nerve to the temporofacial branch and from the hypoglossal nerve (30%) to the cervicofacial branch. Traditionally, the stimulus coming from the masseteric nerve is directed in that way to both the orbicularis oculi and the great zygomatic muscle, leading to eye-mouth synkinesis. The evolved technique connects the masseteric nerve more distally on the branch directed to the great zygomatic muscle and the hypoglossal nerve (30%) to the main trunk of the injured facial nerve. Long-term follow-up could be interesting to check what happens to the eye without the stimulus coming from the masseteric nerve.

Methods

Exactly 32 patients were included, subdivided into two groups based on the type of surgical technique. Static symmetry, voluntary movements, and synkinesis were evaluated with eFACE software.

Results

Both techniques allowed to obtain excellent outcomes: pre- and post-operative parameters showed a statistically significant improvement in both groups and no differences between the two groups, except in palpebral fissure width forced eye closure, in oculo and midfacial synkinesis: a significant reduction of synkinesis was evident in the evolved version group.

Conclusions

The new triple innervation offers significant improvements in reducing synkinesis, ocular and mid-facial muscle spasm, leading to a more relaxed tone at rest.