Independence of Facial Movements from the Tongue Following Hypoglossal-to-Facial Nerve Transfer Using the Plasticity Grading Score.

Background

Nerve transfers can restore lost motor function in cases of facial palsy, with recovery reliant on brain plasticity enabling volitional control.

Objective

To quantify clinical and treatment factors influencing independent facial motor recovery after hypoglossal-to-facial nerve transfer.

Methods

Patients with complete unilateral facial palsy who underwent hypoglossal (resultsXII) to facial (CNVII) nerve transfer were analyzed. Brain plasticity was graded using a 4-point Plasticity Grading Scale (PGS). Patient variables, including age, sex, surgical timing, follow-up duration, and rehabilitation quality, were recorded and analyzed for their relationship with PGS scores.

Results

Sixty-six patients were included, with a median age of 45 years, of which 62% were male. Plasticity was classified as poor in 53% and absent in 41% of patients. No patient achieved complete independence of facial muscles from tongue movements. Higher PGS scores were associated with earlier surgical intervention (≤6 months post-trauma; p = 0.008), younger age (p = 0.001), and adherence to rehabilitation at a specialized neurorehabilitation center (p = 0.002).

Conclusions

Brain plasticity after hypoglossal-to-facial nerve transfer is often limited, failing to achieve independence of facial muscles from the donor nerve. Early intervention, younger age, and specialized rehabilitation enhanced functional recovery.