Selective Neurectomy for Treatment of Post-Facial Paralysis Synkinesis: A Systematic Review

The Role of Botulinum Toxin A Neuromodulator in the Management of Synkinesis in Facial Palsy

Facial palsy describes the denervation of the facial nerve leading to difficulty in facial animation and expression. Facial synkinesis is the result of complex pathological nerve regeneration following damage to the facial nerve axons. Synkinesis in facial palsy can be managed using facial neuromuscular rehabilitation, botulinum toxin neuromodulators, and surgical treatment options. Botulinum toxin A can be used as an adjunct to other treatment options to manage synkinesis. This article will explore the role of botulinum toxin A in the management of synkinesis in facial palsy including the clinical assessment, injection location (muscles targeted), dosages, treatment interval, and long-term results. It will also include surgical management options.

How to Enhance the Success of Selective Neurectomy for Facial Synkinesis by Considering the Patient's Preferences: Lesson Learned from a Retrospective Analysis of 122 Cases

BACKGROUND

Facial synkinesis can result in facial tightness, smile dysfunction, and eyelid aperture narrowing due to overactive and uncoordinated muscle activity. We hypothesized that the outcome of a selective neurectomy could rely on the patient's chief complaints.

METHODS

We retrospectively reviewed 122 patients who underwent selective neurectomy at our hospital. Preoperatively, the patients were asked nine questionnaires to identify their two major chief complaints (treatment priorities). Postoperatively, facial tightness, limited mouth movement, and eyelid aperture narrowing were measured.

RESULTS

The most common chief complaints in our series were facial tightness (n=38), eyelid narrowing (n=32), and limited mouth movement (n=28); the second most common chief complaints (second priority) were limited mouth movement (n=47), facial tightness (n=21), and eyelid narrowing (n=20). The mean score for facial tightness significantly improved from 4.3 to 1.1 in the first priority group. Among the 28 patients whose corners of the mouth constituted the top priority of surgical correction, the vertical inclination on the affected side significantly improved from 74.1 ± 7.6° to 55.5 ± 6.0°, and the horizontal angles were changed from 4.2 ± 2.7° to 2.0 ± 1.3° after selective neurectomy without statistically significant. Among the 32 patients for whom eyelid narrowing constituted the top priority, the mean eyelid narrowing score improved from 4.5 ± 1.1 to 1.5 ± 1.2.

CONCLUSIONS

Selective neurectomy can provide a significantly satisfactory outcome regarding facial tightness and eyelid aperture narrowing. The vertical inclination of the mouth corner can be significantly improved, while the improvement of horizontal angles can be suboptimal.

LEVEL OF EVIDENCE IV

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Pre-Operative Factors May Predict Outcome in Selective Neurectomy for Synkinesis

Background: While there has been great interest in offering selective neurectomy (SN) to patients with nonflaccid facial palsy (NFFP), postoperative outcomes are inconsistent. Objective: To assess overall SN outcome in NFFP patients and to examine correlation between preoperative factors and SN outcome. Methods: SN cases were retrospectively identified between 2019 and 2021. Patient factors and facial function were assessed using chart review, the Facial Clinimetric Evaluation (FaCE), the electronic clinician-graded facial function tool (eFACE), and an automated computer-aided facial assessment tool (Emotrics). Correlations between preoperative factors and patients outcome were established. Results: Fifty-eight SN cases were performed; 88% were females, and median age was 53 years (range 11-81). Outcome assessment was 8 months on average (1-24 months). Postoperatively, multiple eFACE and Emotrics parameters improved significantly, including ocular, perioral, and synkinesis metrics. In preoperative factors assessment, age >50, facial palsy (FP) duration >2 years, poor preoperative facial function, and nontrauma etiology all correlated with greater improvements compared with younger patients, those with shorter duration facial palsy, trauma etiology, and better preoperative facial function. Conclusions: SN can significantly improve facial function; we have identified several preoperative factors that correlated to outcome.

Facial Paralysis Treatment Using Selective Neurectomy: A Comprehensive Review

Facial paralysis can affect patients undergoing full mouth rehabilitation, regardless of what caused their paralysis. A procedure known as modified selective neurectomy of the facial nerve can enhance the movement of facial muscles in individuals with facial synkinesis safely and effectively. This approach is proposed as an alternative to more invasive surgical options when used independently as a treatment for incomplete facial palsy. Selective neurectomy offers a promising surgical option for managing nonflaccid facial paralysis and synkinesis, enhancing patients' quality of life. However, treatment plans should be individually tailored considering the complexity of facial paralysis and the unique needs of each patient, taking into account the timing and type of treatment. The objective of this review is to explore the use of selective neurectomy as a treatment for facial paralysis based on previously published papers.