Masseteric nerve use in facial reanimation:

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.

The Selective Trigeminal Nerve Motor Branching Transfer: an Preliminary Clinical Application for Facial Reanimation

OBJECTIVE

To investigate the effectiveness and feasibility of selective trigeminal nerve motor branching in the repair of facial palsy.

MATERIALS AND METHODS

The clinical data of patients with advanced facial palsy from 2016 to 2021 were retrospectively analyzed, including pictures and videos before and 18 months after surgery. The House-Brackmann grading system was used to evaluate facial nerve function before and after repair, and the symmetry scale of oral commissure at rest and Terzis' smile functional evaluation scale were used to qualitatively assess the symmetry of the mouth angle and smile function. The distance of oral commissure movement was assessed to evaluate the dynamic repair effect, and the FaCE facial muscle function scale was used to assess patients' subjective perception before and after surgery.

RESULTS

A total of four patients were included in the study, all of whom showed signs of recovery of facial nerve function within six months. In all four cases, significant improvements were observed in House-Brackmann ratings, the smile function score and the symmetry scale of oral commissure at rest. Compared to the pre-operative period, the four patients demonstrated various degrees of eye-closing function recovery, and a significant improvement in oral commissure movement was observed ( P <0.001). FaCE scores also improved significantly after surgery ( P =0.019).

CONCLUSION

Concurrent selective facial nerve repair with trigeminal branch-facial nerve anastomosis resulted in eye-closing function recovery while improving static and dynamic symmetry, yielding acceptable postoperative results.

Advances in Facial Reanimation

Facial nerve paralysis is a debilitating clinical entity that presents as a complete or incomplete loss of facial nerve function. The etiology of facial nerve palsy and sequelae varies tremendously. The most common cause of facial paralysis is Bell's palsy, followed by malignant or benign tumors, iatrogenic insults, trauma, virus-associated paralysis, and congenital etiologies.

The Experience of a Facial Nerve Unit in the Treatment of Patients With Facial Paralysis Following Skull Base Surgery

: The management of facial paralysis following skull base surgery is complex and requires multidisciplinary intervention. This review shows the experience of a facial nerve (FN) unit in a tertiary university referral center. A multidisciplinary approach has led to the breaking of some old treatment paradigms. An overview of five FN scenarios is presented. For each setting a contemporary approach is proposed in contrast to the established approach. 1) For patients with an anatomically preserved FN with no electrical response at the end of surgery for vestibular schwannoma, watchful waiting is usually advocated. In these cases, reinforcement with an interposed nerve graft is recommended. 2) In cases of epineural FN repair, with or without grafting, and a poor expected prognosis, an additional masseter-to-facial transfer is recommended. 3) FN transfer, mainly hypoglossal-to-facial and masseter-to facial, are usually chosen based on the surgeons' preference. The choice should be based on clinical factors. A combination of techniques improves the outcome in selected patients. 4) FN reconstruction following malignant tumors requires a combination of parotid and temporal bone surgery, involving different specialists. This collaboration is not always consistent. Exposure of the mastoid FN is recommended for lesions involving the stylomastoid foramen, as well as intraoperative FN reconstruction. 5) In patients with incomplete facial paralysis and a skull base tumor requiring additional surgery, consider an alternative reinnervation procedure, "take the FN out of the equation" before tumor resection. In summary, to achieve the best results in complex cases of facial paralysis, a multidisciplinary approach is recommended.

Long-term outcomes of dual innervation in functional muscle transfers for facial palsy

BACKGROUND

This study describes a different approach with a 2-stage facial reanimation in patients with long-standing unilateral facial paralysis using free gracilis muscle transfer, innervated by both cross-facial nerve graft and masseteric nerve. The authors present their rationale, surgical technique, and long-term outcomes.

METHODS

Between August 2012 and March 2016, 11 patients (6 female and 5 male patients) underwent a 2-staged dually innervated gracilis muscle transfer. Patients were evaluated with physical examination and needle electromyography. A standardized assessment of preoperative and postoperative photographs and videos was performed using Terzis' smile functional grading system at 48 months following surgery and the Emotrics software to assess improvement in symmetry over a 36-month postoperative period.

RESULTS

Voluntary contraction of the gracilis muscle was observed in all patients at a mean of 4 months and 4 days following muscle transfer. A spontaneous smile produced without teeth clenching was developed in all patients by 18 months postoperatively. Six patients achieved excellent and 5 good results. The difference between the averaged pre- and postoperative scores was statistically significant. With Emotrics, there were significant improvements in the smile angle, upper lip elevation, commissural excursion, and commissural height, with continuous improvement over 36 months. The postoperative electromyography (EMG) confirmed dual innervation of the gracilis muscle by the facial and masseteric donor motor neural sources. We present our results at minimum 48 months postoperatively.

CONCLUSIONS

Dual innervated two-stage gracilis transfer is an effective method for reanimation in long-standing unilateral facial paralysis, providing both rapid reinnervation of the transferred muscle, together with a powerful, synchronous smile.

Masseter nerve-based facial palsy reconstruction

Facial paralysis is a devastating disease, the treatment of which is challenging. The use of the masseteric nerve in facial reanimation has become increasingly popular and has been applied to an expanded range of clinical scenarios. However, appropriate selection of the motor nerve and reanimation method is vital for successful facial reanimation. In this literature review on facial reanimation and the masseter nerve, we summarize and compare various reanimation methods using the masseter nerve. The masseter nerve can be used for direct coaptation with the paralyzed facial nerve for temporary motor input during cross-facial nerve graft regeneration and for double innervation with the contralateral facial nerve. The masseter nerve is favorable because of its proximity to the facial nerve, limited donor site morbidity, and rapid functional recovery. Masseter nerve transfer usually leads to improved symmetry and oral commissure excursion due to robust motor input. However, the lack of a spontaneous, effortless smile is a significant concern with the use of the masseter nerve. A thorough understanding of the advantages and disadvantages of the use of the masseter nerve, along with careful patient selection, can expand its use in clinical scenarios and improve the outcomes of facial reanimation surgery.

Facial nerve transfer for facial reanimation with parotidoplasty approach

BACKGROUND

Facial paralysis has a profound impact on quality of life in affected individuals, primarily through loss of verbal and nonverbal communication. Common facial nerve reanimation techniques include coaptation to the masseteric or hypoglossal nerve. Most techniques require nerve grafts to achieve a tension-free neurorrhaphy. Our report aims to show a surgical adaption to current facial reanimation procedures using a partial parotidoplasty approach in order to avoid challenges caused by interpositional nerve grafts through primary neurorrhaphy.

PATIENTS AND METHODS

The modified surgical approach was performed on four patients, aged 30-67. Length of paralysis ranged from 6 to 13 months. Cause of paralysis included one patient with Bell's palsy in one patient, prior surgery in two patients, and traumatic fracture in the remaining patient. A modified Blair approach is used to expose the parotid capsule. The facial nerve is dissected proximally toward the stylomastoid foramen and distally toward the masseter. The parotid gland substance is sectioned overlying each branch of the facial nerve using ultrasonic dissection or hemostatic scalpel, allowing mobilization of the proximal segment and upper and lower divisions of the facial nerve. The superficial lobe of the parotid is preserved in most cases. The House-Brackmann (H-B) functional scale was used to assess facial nerve function pre- and post-operatively.

RESULTS

All patients showed H-B score V or greater prior to reanimation. Follow-up was conducted at 3-, 6-, and 12-months in all patients with resultant improvement of H-B scores of I in three patients and II in the remaining patient. Only one complication was noted, with one patient developing a right postauricular hematoma that was adequately managed without sequelae. All remaining patients experienced an uncomplicated post-operative course.

CONCLUSION

Our modified approach to facial nerve reanimation works well with a planned parotidoplasty allowing for successful reanimation outcomes without the need for interpositional grafting. This technique may be considered in masseteric and hemi-hypoglossal nerve transfers for the reinnervation of facial muscles.

Masseteric-to-Facial Nerve Transfer and Selective Neurectomy for Rehabilitation of the Synkinetic Smile

Importance

Synkinesis is the involuntary movement of 1 area of the face accompanying volitional movement of another; it is commonly encountered in patients affected by facial palsy. Current treatments for synkinesis include biofeedback for muscular retraining and chemodenervation via the injection of botulinum toxin. Chemodenervation is effective in reducing unwanted muscle movement, but it requires a commitment to long-term maintenance injections and may lose effectiveness over time. A permanent solution for synkinesis remains elusive.

Objective

To evaluate masseteric-to-facial nerve transfer with selective neurectomy in rehabilitation of the synkinetic smile.

Design, Setting, and Participants

In this case series, 7 patients at a tertiary care teaching hospital underwent masseteric-to-facial nerve transfer with selective neurectomy for synkinesis between September 14, 2015, and April 19, 2018. The medical records of these patients were retrospectively reviewed and demographic characteristics, facial palsy causes, other interventions used, and changes in eFACE scores were identified.

Intervention

Masseteric-to-facial nerve transfer.

Main Outcomes and Measures

Changes in eFACE scores (calculated via numeric scoring of many sections of the face, including flaccidity, normal tone, and hypertonicity; higher scores indicate better function and lower scores indicate poorer function) and House-Brackmann Facial Nerve Grading System scores (range, 1-6; a score of 1 indicates normal facial function on the affected side, and a score of 6 indicates absence of any facial function [complete flaccid palsy] on the affected side).

Results

Among the 7 patients in the study (6 women and 1 man; median age, 49 years [range, 41-63 years]), there were no postoperative complications; patients were followed up for a mean of 12.8 months after surgery (range, 11.0-24.5 months). Patients experienced a significant improvement in mean (SD) eFACE scores in multiple domains, including smile (preoperative, 65.00 [8.64]; postoperative, 76.43 [7.79]; P = .01), dynamic function (preoperative, 62.57 [15.37]; and postoperative, 75.71 [8.48]; P = .03), synkinesis (preoperative, 52.70 [4.96]; and postoperative, 82.00 [6.93]; P < .001), midface and smile function (preoperative, 60.71 [13.52]; and postoperative, 78.86 [14.70]; P = .02), and lower face and neck function (preoperative, 51.14 [16.39]; and postoperative, 66.43 [20.82]; P = .046). Preoperative House-Brackmann Facial Nerve Grading System scores ranged from 3 to 4, and postoperative scores ranged from 2 to 3; this change was not significant.

Conclusion and Relevance

This study describes the application of masseteric-to-facial nerve transfer with selective neurectomy for smile rehabilitation in patients with synkinesis, with statistically significant improvement in smile symmetry and lower facial synkinesis as measured with the eFACE tool. This technique may allow for long-term improvement of synkinesis and smile. This study is only preliminary, and a larger cohort will permit more accurate assessment of this therapeutic modality.

Level of Evidence

4.

Contemporary Concepts of Primary Dynamic Facial Nerve Reconstruction in the Oncologic Patient

Transection of the facial nerve and its branches during extensive ablative procedures in the oncologic patient causes loss of control of facial mimetic muscles with severe functional and aesthetic sequelae. In such patients with advanced tumorous disease, copious comorbidities, and poor prognosis, rehabilitation of the facial nerve has long been considered of secondary priority. However, recent advances in primary facial nerve reconstruction after extensive resection demonstrated encouraging results focusing on rapid and reliable restoration of facial functions. The authors summarize 3 innovative approaches of primary dynamic facial nerve reconstruction by using vascularized nerve grafts, dual innervation concepts, and intra-facial nerve transfers.

Dual Coaptation of Facial Nerve Using Masseteric Branch of Trigeminal Nerve for Iatrogenic Facial Palsy: Preliminary Reports

OBJECTIVES

Immediate facial nerve substitution or graft technique has been used for the repair of facial nerve defects occurring as a result of tumour dissection. However, some patients report unsatisfactory outcomes, such as difficulty in maintaining resting or smiling symmetry, due to persistent flaccid facial palsy. Here we evaluated the functional outcomes of transferring the masseteric branch of the trigeminal nerve to the facial nerve adjunct to facial nerve graft.

METHODS

We reviewed the medical records of seven patients who underwent facial reanimation surgery between 2014 and 2016. The patients were divided into two groups according to the type of facial reanimation surgery: group A, masseteric nerve innervation with interposition graft; group B, interposition graft only. The postoperative resting symmetry and dynamic movement were compared.

RESULTS

Facial contraction was first observed in group A at 4 months and in group B at 7.3 months. Most of the patients achieved reliable resting symmetry; however, one patient in group B exhibited unsatisfactory facial weakness on the affected side. Group A patients showed better dynamic movement than group B patients. Eye closure, oral excursion and oral continence were better in group A than in group B patients. Smile symmetry in both groups was similar due to hyperkinetic movement in group A patients and flaccidity in group B patients.

CONCLUSIONS

Dual innervation of the masseteric branch of the trigeminal nerve improves the dynamic movement of paralysed facial muscles and shortens the recovery period in patients with iatrogenic facial palsy.

Bacterial cellulose tubes as a nerve conduit for repairing complete facial nerve transection in a rat model

PURPOSE

Functionality of the facial nerve is cosmetically important. While many techniques have been investigated, early and effective treatment for traumatic facial nerve paralysis remains challenging. Here, we aim to examine bacterial cellulose (BC) as a new tubularization material for improving facial nerve regeneration.

METHODS

Our study was performed on 40 female Sprague Dawley rats. Rats were randomly divided into four groups, with 10 rats per group. In all rats, the main trunk of the facial nerve was completely cut 8 mm before the branching point. For repairing the facial nerve, in group 1, the nerve was left to recover spontaneously (control group); in group 2, it was repaired by primary suturing (8.0 Ethilon sutures, Ethicon); in group 3, BC tubes alone were used to aid nerve repair; and in group 4, both BC tubes and primary sutures (8.0 Ethilon sutures) were used. After 10 weeks, the facial nerve regeneration was evaluated by the whisker movement test and electrophysiologically (nerve stimulation threshold and compound muscle action potential). Nerve regeneration was assessed by calculating the number of myelinated nerve fibers, and by microscopically evaluating the amount of regeneration and fibrosis.

RESULTS

No significant difference was observed among the groups in terms of whisker movement and electrophysiological parameters (P > 0.05). We found that the numbers of regenerating myelinated fibers were significantly increased (P < 0.05) when BC tubes were used as a nerve conduit.

CONCLUSIONS

BC can be easily shaped into a hollow tube that guides nerve axons, resulting in better nerve regeneration after transection.

Facial Nerve Translocation for Low Tension Neurorrhaphy to Masseteric Nerve

INTRODUCTION

The techniques of facial reanimation are continually evolving in search of the ideal method for rehabilitating the paralyzed face. In the past, alternative cranial nerve motor nuclei have been used to power facial musculature. The trigeminal nerve is gaining popularity as a promising nerve to drive facial motion, particularly in the lower face.

OBJECTIVES

This article describes a low-tension technique of using the transposed facial nerve to the trigeminal nerve (masseteric branch) for facial reanimation.

METHODS

Six patients over 2.5 years were treated with facial nerve translocation with division at the geniculate and direct neurorrhaphy to the motor branch of the masseter. Patients were evaluated by physical examination, measurement of oral commissure excursion using MEEI FACE-gram software, video assessment, Sunnybrook Facial Grading System, Facial Disability Index, and Facial Clinimetric Evaluation Scale (FaCE).

RESULTS

Patients demonstrated early motion within 4 months postoperatively and were placed into facial physical therapy. All demonstrated improvements in oral competence, strong oral commissure excursion with good symmetry, speech improvements, and variable results in facial tone. Synkinesis to the smile antagonists in the lower face was noted and treated with chemodenervation in three of six. No upper division synkinesis was noted.

CONCLUSION

The motor branch of the trigeminal nerve is an effective option for facial reanimation via facial nerve translocation and end-to-end neurorrhaphy. Variable results in facial tone were noted with excellent oral commissure excursion. This procedure is safe in the reoperated mastoid.

Masseter-to-Facial Nerve Transfer for Reanimation of a Patient With Long-Term Facial Paralysis

Facial paralysis is a condition caused by a wide variety of etiologies, including neurologic, congenital, infectious, neoplastic, systemic, and iatrogenic causes. A patient suffering from long-term facial paralysis, with minimal innervation detected through electroneurography, who was successfully reanimated by performing a masseter-to-facial nerve transfer, was presented in this study. Facial paralysis had been caused after resection of an acquired middle ear cholesteatoma more than 5 years before.

Management of the facial nerve in parotid cancer: preservation or resection and reconstruction

PURPOSE

Management of the facial nerve is instrumental in the surgical treatment of parotid cancer.

METHODS

A literature search was conducted using PubMed and ScienceDirect database. A total of 195 articles were finally included into the analysis, based on relevance, scientific evidence and actuality.

RESULTS

In the majority of cases the facial nerve is not involved by tumor. In these cases, identification and preservation of the nerve, in addition to complete tumor removal, are essential for successful surgery. When the nerve is infiltrated by tumor, the affected portion of the nerve must be resected as part of radical parotidectomy. Primary nerve reconstruction or other reanimation techniques give the best long-term functional and cosmetic results. A comprehensive diagnostic evaluation with current imaging and electrophysiological studies will provide the surgeon with the best knowledge of the relationship of the facial nerve to the tumor. Several standardized methods are helpful in finding, dissecting and preserving the nerve during parotid cancer surgery. When radical parotidectomy is indicated, the initial diagnostic work-up can assist in defining the need for adjuvant postoperative therapy and facial reanimation. The aim of rehabilitation is to restore tone, symmetry, and movement to the paralyzed face.

CONCLUSIONS

The surgical management of facial paralysis has undergone many improvements in recent years. This review gives an overview of recent advances in the diagnostic work-up, surgical techniques and any necessary rehabilitation of the facial nerve in parotid cancer surgery.

Facial Rehabilitation: Evaluation and Treatment Strategies for the Patient with Facial Palsy

This article describes the most widely used clinician-graded and patient-reported outcome measures, and describes facial rehabilitation strategies for acute and chronic facial palsy, and rehabilitation following dynamic facial reanimation surgery. The multimodality rehabilitation of the facial palsy patient is determined by the extent of facial nerve injury, specific functional deficits, the presence of synkinesis, and the patient's individual goals. Appropriate intervention, including patient education, soft tissue mobilization, neuromuscular reeducation, and chemodenervation, decreases facial tension and improves facial muscle motor control, physical function, facial expression, and quality of life.

[Rehabilitation of facial palsy and vertigo in patients with vestibular schwannoma]

BACKGROUND

Facial palsy and vertigo, as symptoms of vestibular schwannoma (VS) or consequences of its therapy, have a significant impact on patients' quality of life.

OBJECTIVE

This review analyzed current literature on the topic and deduced recommendations for rehabilitation of facial palsy and vertigo.

METHODS

The present review describes a PubMed-based search of the literature of the past 10 years.

RESULTS

There is no evidence-based drug therapy for the treatment of acute facial palsy after VS surgery. Several surgical procedures for facial nerve reconstruction, muscle transfer, and static techniques have been established. Physiotherapeutic movement therapy, optimally with biofeedback, seems to improve facial function in patients with post-paralytic syndrome. Botulinum toxin injections are the method of choice for synkinesis treatment. For treatment of acute and chronic vertigo in patients with VS, the same antivertiginous drugs as for other vertigo patients are used. If the patient shows retained vestibular stimulation function, preoperative intratympanic gentamycin therapy followed by compensation training is a promising approach to decreasing postoperative vertigo. Good vestibular rehabilitation comprises intensive and regular movement training, preferably with real-time feedback and therapy control.

CONCLUSION

There are several conservative, surgical, or combined conservative-surgical treatment options for individualized facial nerve rehabilitation of VS patients, as confirmed by clinical studies. In cases of acute vertigo, standard antivertiginous pharmacotherapy is indicated. In cases of acute and also of chronic vertigo, intensive balance and movement training relieves complaints.

Overview of Facial Plastic Surgery and Current Developments

Facial plastic surgery is a multidisciplinary specialty largely driven by otolaryngology but includes oral maxillary surgery, dermatology, ophthalmology, and plastic surgery. It encompasses both reconstructive and cosmetic components. The scope of practice for facial plastic surgeons in the United States may include rhinoplasty, browlifts, blepharoplasty, facelifts, microvascular reconstruction of the head and neck, craniomaxillofacial trauma reconstruction, and correction of defects in the face after skin cancer resection. Facial plastic surgery also encompasses the use of injectable fillers, neural modulators (e.g., BOTOX Cosmetic, Allergan Pharmaceuticals, Westport, Ireland), lasers, and other devices aimed at rejuvenating skin. Facial plastic surgery is a constantly evolving field with continuing innovative advances in surgical techniques and cosmetic adjunctive technologies. This article aims to give an overview of the various procedures that encompass the field of facial plastic surgery and to highlight the recent advances and trends in procedures and surgical techniques.

The effective stimulating pulse for restoration of blink function in unilateral facial nerve paralysis rabbits, verified by a simple FES system

The trains of 200 ms biphasic square pulses with the width of 9 ms delivered at 50 Hz were found to be the most suitable and effective mean as stimulation in FES system of restoring the blink function in unilateral facial nerve paralysis rabbit model. FES system is a reliable tool for these patients. Facial paralysis affects thousands of people every year. Many will have long term facial difficulties and the loss of the ability to blink the eye, which can lead to potential loss of the eye. Although many treatments exist, no one approach corrects all the deficits associated with the loss of orbicularis oculi function. FES is a means of providing movement in paralysed muscles to assist with practical activities and one possible way of restoring blink and other functions in these patients. Although some previous researches had investigated the effect of simple FES system on restoration of paralyzed facial muscles, there is still controversy about the appropriate details of the most effective stimulating pulses, such as the frequency, wave pattern and pulse width. Our aim is to find out the parameters of the most appropriate and effective stimulatin verify it by a simple FES system. 24 healthy adult male New Zealand white rabbits were accepted the surgery of right side facial nerve main trunk transaction under general anesthesia as the unilateral facial nerve paralysis models. The platinum tungsten alloy electrodes were implanted in orbicularis oculi muscle. The parameters of stimulus pulses were set to a 200 ms biphasic pulse with different waveforms (square, sine and triangle), different frequencies (25, 50, 100 Hz) and different widths from 1 to 9 ms. Next, we set up a simple FES system to verify the previous results as the stimulus signal. We observed the movement of the both sides of eyelid when eye blink induced by different kinds of pulses. In all animals, the three kinds of waveforms pulse with frequency of 25 Hz could not evoke the smooth blink movement. But the pulses with frequency of 50 and 100 Hz can achieve this effect. The voltage threshold of the square pulse was lower than that of the sine pulse and triangle pulse. With the increase of pulse width from 1 to 9 ms, the voltage threshold decreased gradually. The voltage threshold of the pulse with frequency of 100 Hz was obviously lower than that of 50 Hz. But the amount of total charge of the stimulation pulse of 100 Hz was significantly more than that of 50 Hz. In addition, when the FES system was turned on, the eye blink on the affected side with the stimulation pulses that were set by the previous step results was successfully aroused by the blink movement as a trigger on the contralateral.

Motor Nerve Transfers

Brachial plexus and peripheral nerve injuries are exceedingly common. Traditional nerve grafting reconstruction strategies and techniques have not changed significantly over the last 3 decades. Increased experience and wider adoption of nerve transfers as part of the reconstructive strategy have resulted in a marked improvement in clinical outcomes. We review the options, outcomes, and indications for nerve transfers to treat brachial plexus and upper- and lower-extremity peripheral nerve injuries, and we explore the increasing use of nerve transfers for facial nerve and spinal cord injuries. Each section provides an overview of donor and recipient options for nerve transfer and of the relevant anatomy specific to the desired function.