Masseteric-facial nerve neurorrhaphy: results of a case series

Facial nerve reconstruction for flaccid facial paralysis: a systematic review and meta-analysis

Objectives

To determine the functional outcome after facial nerve reconstruction surgery in patients with flaccid facial paralysis.

Methods

A systematic review and meta-analysis was performed on studies reporting outcomes after direct facial nerve suture (DFS), facial nerve interpositional graft suture (FIGS), hypoglossal-facial nerve suture (HFS), masseteric-facial nerve suture (MFS), and cross-face nerve suture (CFS). These studies were identified from PubMed/MEDLINE, Embase, and Web of Science databases. Two independent reviewers performed two-stage screening and data extraction. A favorable result was defined as a final House-Brackmann grade I-III and is presented as a ratio of all patients in percentage. Pooled proportions were calculated using random-effects models.

Results

From 4,932 screened records, 54 studies with 1,358 patients were included. A favorable result was achieved after DFS in 42.67% of the patients [confidence interval (CI): 26.05%-61.12%], after FIGS in 66.43% (CI: 55.99%-75.47%), after HFS in 63.89% (95% CI: 54.83%-72.05%), after MFS in 63.11% (CI: 38.53%-82.37%), and after CFS in 46.67% (CI: 24.09%-70.70%). There was no statistically significant difference between the techniques (Q = 6.56, degrees of freedom = 4, p = 0.1611).

Conclusions

The established facial nerve reconstruction techniques including the single nerve cross-transfer techniques produce satisfactory results in most of the patients with permanent flaccid facial paralysis. An international consensus on standardized outcome measures would improve the comparability of facial reanimation techniques.

The masseteric nerve for facial reanimation: Macroscopic and histomorphometric characteristics in 106 human cadavers and comparison of axonal ratio with recipient nerves

Peripheral facial palsy causes severe impairments. Sufficient axonal load is critical for adequate functional outcomes in reanimation procedures. The aim of our study was to attain a better understanding of the anatomy of the masseteric nerve as a donor, in order to optimize neurotization procedures. Biopsies were obtained from 106 hemifaces of fresh frozen human cadavers. Histological cross-sections were fixed, stained with PPD, and digitized. Histomorphometry and a validated software-based axon quantification were conducted. Of the 154 evaluated branches, 74 specimens were of the main trunk (MT), 40 of the anterior branch (AB), and 38 of the descending branch (DB), while two halves of one cadaver featured an additional branch. The MT showed a diameter of 1.4 ± 0.41 mm (n = 74) with 2213 ± 957 axons (n = 55). The AB diameter was 0.9 ± 0.33 mm (n = 40) with 725 ± 714 axons (n = 30). The DB diameter was 1.15 ± 0.34 mm (n = 380) with 1562 ± 926 axons (n = 30). The DB demonstrated a high axonal capacity - valuable for nerve transfers or muscle transplants. Our findings should facilitate a balanced selection of axonal load, and are potentially helpful in achieving more predictable results while preserving masseter muscle function.

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.

Facial Reanimation After Peripheral Facial Nerve Paralysis: A Single-institution Surgical Experience

Facial nerve trauma occasionally develops during oral and maxillofacial surgery. This study was aimed at enhancing the available knowledge on facial nerve reanimation correlated to surgery and proposing our surgical algorithm. We retrospectively analyzed medical records of patients who underwent facial reanimation surgery at our hospital. The inclusion criterion was surgery for facial reanimation from January 2004 to June 2021. We included 383 eligible patients who underwent facial reanimation surgery. Trauma or maxillofacial neoplasms were noted in 208 of 383 and 164 of 383 cases, respectively. In 238 of 383 cases, nerve branches were likely more vulnerable. Facial nerve anastomosis was performed in 256 patients. Sixty-eight patients received nerve grafts. In 22 patients, distal facial nerve transfer to the masseteric nerve, sublingual nerve, or contralateral facial nerve was performed. Twenty-five patients received static surgery; in most cases, the temporalis fascia flap (20/25) was used. The nerve function outcomes were HB grade I (n=17), Grade Ⅱ (n=108), Grade Ⅲ (n=118), Grade Ⅳ (n=94), and Grade V (n=46). The mean follow-up time was 4.88 ± 3.93 years. Facial paralysis caused by trauma ( P =0.000), branch injury ( P =0.000), and the primary reconstruction of facial nerve ( P =0.000) were predictive of favorable treatment outcomes. Although facial nerve injury caused by trauma was more likely, cases of interference in facial expression could be limited, and so did the injury to branches. Nerve anastomosis was prioritized if a tension-free suture was possible. Maintaining the integrity of the nerve and shortening the duration of mimetic muscular denervation were crucial.

V to VII Nerve Transfer for Smile Reanimation

Using the wording "facial reanimation," surgeons mean restoring movements to the paralyzed face. According to the condition of mimic muscle, facial palsy can be classified as recent (mimic muscle still alive) and chronic (atrophy of mimic muscle) palsy. The treatment is quite different because in the former group the mimic muscles can be still used so long as a new motor source would be connected to the damaged facial nerve. In the latter group, muscular transplantation is needed to substitute the atrophied mimic muscles of the middle part of the face. In both cases, the neural impulse that makes the muscles (mimic muscle in the former, transplanted muscle in the latter) move come from a new motor nerve. Nowadays, the masseteric nerve is widely used as a new motor source in recent facial reanimation; the same nerve has also a main role in the treatment of both chronic facial palsy where it is used as the new nervous stimulus for the new transplanted muscle and facial paresis where the nervous stimulus coming from the masseteric nerve is used to empower the stimulus coming from the injured facial nerve. The masseteric nerve can be usually connected directly to the facial nerve without the interposition of a nerve graft, with a faster reinnervation. Moreover, the use of the masseteric nerve gives no morbidity to the masticatory functions.

Smile Reanimation with Masseteric-to-Facial Nerve Transfer plus Cross-Face Nerve Grafting in Patients with Segmental Midface Paresis: 3D Retrospective Quantitative Evaluation

Facial paresis involves functional and aesthetic problems with altered and asymmetric movement patterns. Surgical procedures and physical therapy can effectively reanimate the muscles. From our database, 10 patients (18–50 years) suffering from unilateral segmental midface paresis and rehabilitated by a masseteric-to-facial nerve transfer combined with a cross-face facial nerve graft, followed by physical therapy, were retrospectively analyzed. Standardized labial movements were measured using an optoelectronic motion capture system. Maximum teeth clenching, spontaneous smiles, and lip protrusion (kiss movement) were detected before and after surgery (21 ± 13 months). Preoperatively, during the maximum smile, the paretic side moved less than the healthy one (23.2 vs. 28.7 mm; activation ratio 69%, asymmetry index 18%). Postoperatively, no differences in total mobility were found. The activity ratio and the asymmetry index differed significantly (without/with teeth clenching: ratio 65% vs. 92%, p = 0.016; asymmetry index 21% vs. 5%, p = 0.016). Postoperatively, the mobility of the spontaneous smiles significantly reduced (healthy side, 25.1 vs. 17.2 mm, p = 0.043; paretic side 16.8 vs. 12.2 mm, p = 0.043), without modifications of the activity ratio and asymmetry index. Postoperatively, the paretic side kiss movement was significantly reduced (27 vs. 19.9 mm, p = 0.028). Overall, the treatment contributed to balancing the displacements between the two sides of the face with more symmetric movements.

Bell's palsy misdiagnosis: characteristics of occult tumors causing facial paralysis

Objective

The aim of this study was to report the incidence and clinical course of a series of patients who were misdiagnosed with Bell’s palsy and were eventually proven to have occult neoplasms.

Methods

Two hundred forty patients with unilateral facial paralysis who were assessed at the facial nerve reanimation clinic, Victoria Hospital, London Health Science Centre, from 2008 through 2017 were reviewed. Persistent paralysis without recovery was the presenting complaint.

Results

Nine patients (3.8%) who were proven to have occult neoplasms initially presented with a diagnosis of Bell’s palsy. The mean diagnostic delay was 43.5 months. Four patients were proven to have skin cancers, 3 patients had parotid cancers, and 2 patients had facial nerve schwannomas as a final diagnosis. Initial magnetic resonance imaging (MRI) was performed in all 9 patients and 8 underwent a follow-up MRI. An occult tumor was identified upon review of the original MRI in one patient and at follow-up MRI in 8 patients. The mean time interval between the initial and follow-up imaging was 30.8 months. The disease status at most recent follow-up were no evidence of disease in 2 patients (22%) and alive with disease in 7 patients (78%). An irreversible, progressive pattern of facial paralysis combined with pain, multiple cranial neuropathies or history of skin cancer were predictable risk factors for occult tumors. Seven out of the 9 patients (77.8%) underwent at least one type of facial reanimation surgery, and the final subjective results by the surgeon were available for 5 patients. Three out of the 5 (60%) patients who were available for final subjective analysis were reported as Grade III according to the modified House-Brackmann scale.

Conclusion

Occult facial nerve neoplasm should be suspected in patients with progressive and irreversible facial paralysis but the diagnosis may only become evident with follow-up imaging. Facial reanimation surgery is a satisfactory option for these patients.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40463-022-00591-9.

Masseteric-to-facial nerve transfer for treatment of pediatric facial paralysis: An initial report

OBJECTIVES

The indications and outcomes of masseteric-to-facial nerve transfer in pediatric patients with short-term facial paralysis is incompletely understood as compared to its use in adult patients. This report aims to retrospectively quantify outcomes with both clinician-based measurements and objective facial analysis software.

METHODS

Retrospective case series at a single institution. The Sunnybrook Facial Grading System was used for clinician-based measurements and Emotrics software for objective measurements.

RESULTS

Four pediatric patients underwent masseteric-to-facial nerve transfers from 2016 to 2018. The mean patient age at the time of surgery was 4.5 years (range = 2-7) and the mean time from paralysis onset to surgical intervention was 12.9 months (range = 10.0-16.2). The mean follow-up was 18.3 months (range = 14.5-23.6). With regards to the Sunnybrook resting nasolabial fold symmetry, 3 of the 4 patients improved from 2 (absent nasolabial fold) to 1 (less pronounced nasolabial fold). Per the Emotrics analysis, the pre- and post-operative mean absolute differences for commissure excursion between the normal functioning and paralyzed sides were 11.8 mm and 6.7 mm, respectively (p = 0.04).

CONCLUSION

The masseteric-to-facial nerve transfer technique leads to an objective improvement in dynamic smile function in select pediatric patients.

Multiple Model Evaluation of the Masseteric-to-Facial Nerve Transfer for Reanimation of the Paralyzed Face and Quick Prognostic Prediction

Facial paralysis is negatively associated with functional, aesthetic, and psychosocial consequences. The masseteric-to-facial nerve transfer (MFNT) has many advantages in facial reanimation. The aim is to evaluate the effectiveness of our MFNT technique and define the potential factors predictive of outcome. The authors conducted a retrospective review of 20 consecutive patients who underwent MFNT using the temporofacial trunk of facial nerve. Videotapes and images were documented and evaluated according to Facial Nerve Grading Scale 2.0 (FNGS2.0) and Sunnybrook Facial Grading System (FGS). The quality-of-life was obtained using the Facial Clinimetric Evaluation (FaCE) Scale. Moreover, Facial Asymmetry Index (FAI), quantitative measurement of the width of palpebral fissure, deviation of the philtrum, and angles or excursions of the oral commissure were applied to explore the effect of the transfer metrically. Multivariable logistic regression models and Cox regression were prepared to predict the effect of MFNT by preoperative clinical features. The patients showed favorable outcomes graded by FNGS2.0, and experienced significantly improved scores in static and dynamic symmetry with slightly elevated scores in synkinesis evaluated by the Sunnybrook FGS. The score of FaCE Scale increased in all domains after reanimation. The quantitative indices indicated the symmetry restoration of the middle and lower face after MFNT. Regression analysis revealed that younger patients with severe facial paralysis are preferable to receive MFNT early for faster and better recovery, especially for traumatic causes. The findings demonstrate that MFNT is an effective technique for facial reanimation, and case screening based on clinical characteristics could be useful for surgical recommendation.

Supercharging the Smile: A Novel Dual Nerve Transfer for Facial Reanimation

Facial paralysis has profound effects on the functional and psychosocial well-being of patients. Various surgical facial reanimation techniques have been described to address this devastating condition. While traditional surgical approaches have proved successful in restoring either facial tone or facial movement, newer combination nerve transfer techniques are addressing the limitations of the traditional single nerve transfer approaches.

The Masseteric-Facial Anastomosis With Intratemporal Translocation of the Facial Nerve: Step-by-Step Technique and Results

BACKGROUND

In the absence of a viable proximal nerve stump, damaged after surgical procedures around the skull base, numerous techniques for facial reanimation have been developed over time, aiming to restore baseline symmetry and active mimicry.

OBJECTIVE

To report experience using the masseteric nerve as a direct transfer to the facial nerve rerouted after intratemporal translocation. This paper illustrates the main steps of the technique and the quality of results.

METHODS

Eleven patients were treated with a masseteric direct transfer to the facial nerve. Its extratemporal rerouting toward the zygoma allowed tension-free coaptation between donor and recipient nerves.

RESULTS

Of the 11 patients, 8 had a good to excellent recovery, showing different patterns of time and scores, according to age, surgical timing, and masseteric nerve function quality. The return of activity in the frontalis muscle, never obtained after reinnervation via the hypoglossal nerve, is of particular interest. The quality of the smile can be improved with re-education and practice but remains under volitional control. A true emotional response is still lacking.

CONCLUSION

The masseteric nerve is an excellent alternative to the hypoglossal nerve and can reinnervate the whole territory of the facial nerve rerouted after intratemporal translocation. The overall results are remarkable, but the low quality of the trigeminal nerve, eventually affected by the first surgery, may be an important limitation. Even if the patients appear more at ease in re-education than with other techniques, a fully natural facial expression remains impossible to obtain.

Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives

Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury.

Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base.

Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones.

Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.

Comparison of results utilizing one-step and two-step triple innervation techniques

A retrospective comparison between two groups of patients who underwent one-step or two-step triple innervation was performed to reveal the role of scar tissue in axonal regeneration. The surgical technique used was the same in all cases, but the first group underwent a one-time triple innervation procedure, while patients in the second group underwent delayed performance of neurorrhaphies between the distal ends of the cross-face grafts and the terminal branches of the injured facial nerve. The Wilcoxon signed-rank test for paired groups showed a statistically significant improvement in both facial symmetry and voluntary movements in both groups of patients. Separately, the Mann-Whitney test confirmed no statistically significant difference between the two groups regarding the restoration of facial symmetry and voluntary movements, and the development of postoperative synkinesis. A comparison of median values for each spontaneous parameter between the groups revealed greater effectiveness of the two-step surgery, with both blinking and laughing demonstrating better results. The greater effectiveness of the double-step technique in restoring spontaneous movements strongly supports the use of a two-stage triple innervation technique in patients with facial palsy.

Hypoglossal and Masseteric Nerve Transfer for Facial Reanimation: A Systematic Review and Meta-Analysis

Background: Hypoglossal and masseteric nerve transfer are currently the most popular cranial nerve transfer techniques for patients with facial paralysis. The authors performed a systematic review and meta-analysis to compare functional outcomes and adverse effects of these procedures. Methods: A review of online databases was performed to include studies with four or more patients undergoing hypoglossal or masseter nerve transfer without muscle transfer or other cranial nerve transposition. Facial nerve outcomes, time to reinnervation, and adverse events were pooled and studied. Results: A total of 71 studies were included: 15 studies included 220 masseteric-facial transfers, and 60 studies included 1312 hypoglossal-facial transfers. Oral commissure symmetry at rest was better for hypoglossal transfer (2.22 ± 1.6 mm vs. 3.62 ± 2.7 mm, p = 0.047). The composite Sunnybrook Facial Nerve Grading Scale was better for masseteric transfer (47.7 ± 7.4 vs. 33.0 ± 6.4, p < 0.001). Time to first movement (in months) was significantly faster in masseteric transfer (4.6 ± 2.6 vs. 6.3 ± 1.3, p < 0.001). Adverse effects were rare (<5%) for both procedures. Conclusions: Both nerve transfer techniques are effective for facial reanimation, and the surgeon should consider the nuanced differences in selecting the correct procedure for each patient.

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.

Combining an end to side nerve to masseter transfer with cross face nerve graft for functional upgrade in partial facial paralysis-an observational cohort study

BACKGROUND

Results of a single stage technique combining cross facial nerve graft(s) (CFNG) with an ipsilateral end to side nerve to masseter transfer (NTM) in incomplete facial paralysis are assessed in a retrospective cohort study. The hypothesis is that the technique can safely improve the quality of smile in these patients. End to side coaptations for the recipient facial nerve minimise the risk of iatrogenic function loss, contrasting with the end to end neurorrhaphies used in conventional babysitting procedures.

METHODS

A series of 27 patients was studied through case note review and standardised assessments. Surgical technique involves extensive exposure of the facial nerve and the NTM on the affected side and access is by bilateral preauricular incisions. End to end coaptations are made to the facial nerve on the donor side and on the recipient a standard CFNG is combined with an end to side NTM coaptation. Follow up was a minimum of 9 months from surgery.

RESULTS

Overall improvement in the Sunnybrook scale averaged 33, from a pre-operative score of 40 (p < 0.05). Average upgrade of 4.7 mm of increased movement at the modiolus was achieved (p < 0.05), 43% improvement compared to the normal side. An improved resting symmetry of 3.8 mm was achieved in relevant cases. Where eye closure was strengthened the average improvement was 5 mm of increased lid closure. The smile achieved was spontaneous in 22 of 27 cases.

CONCLUSION

The study confirms the hypothesis that CFNG with NTM transfer offers a physiological upgrade of facial movement in partial facial paralysis, applicable in both early and longstanding cases.

Predicting Resting Oral Commissure Tone Outcomes Following Masseter Nerve Transfer in Facial Reanimation

Objective: To quantify the degree of oral commissure resting tone improvement in patients undergoing masseter to facial nerve transfer. Methods: A retrospective cohort study was completed in a tertiary academic medical practice. Consecutive cases of masseter nerve transfer patients within a patient database were evaluated from 6/2012 to 9/2017. Inclusion criteria were patients >18 years of age, with complete unilateral paralysis, receiving a masseter to facial nerve transfer, with at least 12 months of recovery, and possessing complete pre- and postoperative data. Patients were excluded if a simultaneous adjunctive procedure was performed so that tone could not be attributed to masseter transfer alone. The main outcome measure was the facial asymmetry index (FAI): the measured difference in distance between the medial canthus and oral commissure of the healthy and paralyzed sides. Results: Twenty-nine patients met inclusion and exclusion criteria and were further analyzed for this study. The oral commissure symmetry improved from 4.7 ± 2.8 mm preoperatively to 2.2 ± 2.3 mm postoperatively. In multivariate analysis, the preoperative FAI was the only significant predictive factor for improvement in commissure symmetry at rest (r = 0.589). This suggests that for each 1.0 mm of worse preoperatively oral commissure asymmetry, the improvement postoperatively was 0.6 mm. Age, gender, body mass index, side of paralysis, duration of paralysis, and recipient branch of facial nerve were not significant predictors in a multivariate analysis. Conclusion: Masseter to facial nerve transfer yields an estimated 60% correction in the oral commissure asymmetry. This estimation may be helpful in determining if adjunctive procedures should be utilized.

Hypoglossal-Facial Side-to-End Neurorrhaphy With Concomitant Masseteric-Zygomatic Nerve Branch Coaptation and Muscle Transfer for Facial Reanimation: Technique and Case Report

BACKGROUND

Hypoglossal-facial direct side-to-end neurorrhaphy has become widely used for facial reanimation in patients with irreversible facial nerve damage. Although this procedure achieves good restoration of facial function, it has disadvantages such as mass movement and lack of spontaneity.

OBJECTIVE

To present a new facial reanimation technique using hypoglossal-facial direct side-to-end neurorrhaphy with concomitant masseteric-zygomatic nerve branch coaptation and secondary muscle transfer to reduce mass movement and achieve a spontaneous smile in patients with facial paralysis.

METHODS

This article describes a novel facial reanimation technique that employs hypoglossal and masseteric nerve transfer combined with secondary vascularized functional gracilis muscle transfer.

RESULTS

Details of the technique are reported in a patient with complete facial paralysis after brain surgery. The hypoglossal nerve was partially served and connected to the mastoid segment of the facial nerve by side-to-end anastomosis to restore facial symmetry. A nerve supplying the masseter muscle was coapted with a zygomatic branch by end-to-end anastomosis to restore voluntary movement of the oral commissure, as well as to assist with eye closure. A cross face sural nerve graft was connected to zygomatic branches on the healthy side. In the second stage, a vascularized functional gracilis muscle graft was transplanted using the cross face nerve graft as the donor nerve to restore a natural smile.

CONCLUSION

Hypoglossal-facial neurorrhaphy with concomitant masseteric-zygomatic nerve branch coaptation and muscle transfer is an alternative facial reanimation technique that reduces mass movement and achieves a natural smile.

Orbicularis Oculi Muscle Reinnervation Confers Corneal Protective Advantages over Static Interventions Alone in the Subacute Facial Palsy Patient

BACKGROUND

Corneal protection is a priority in flaccid facial palsy patients. Denervation of the orbicularis oculi muscle results in weak palpebral closure and predisposes patients to severe corneal sequelae. While periorbital static procedures enhance corneal coverage in repose, voluntary closure is only regained through dynamic reinnervation of the muscle. This study aims to elucidate the added effect of dynamic reinnervation of the orbicularis oculi muscle on long-term corneal integrity as well as on dynamic closure of the palpebral aperture.

METHODS

Retrospective review was performed on two groups of complete palsy patients: those who received solely periorbital static procedures and those who underwent concomitant orbicularis oculi muscle reinnervation and static lid procedures. Only patients with complete ophthalmic examinations were included. Corneal punctate epithelial erosions in addition to static and dynamic palpebral measurements were serially assessed preoperatively and postoperatively.

RESULTS

Of 272 facial palsy patients, 26 fit the inclusion criteria. Eleven patients underwent combined muscle reinnervation involving facial-to-masseteric nerve coaptation in addition to static eye procedures, and 15 patients underwent solely static interventions. Analysis revealed a 65.3 percent lower mean punctate epithelial erosion score in reinnervation patients as compared with static patients when evaluated at more than 9 months postoperatively (p < 0.01). Reinnervation patients were also found to have 25.3 percent greater palpebral aperture closure (p < 0.05) and 32.8 percent higher closure velocity (p < 0.01) compared with static patients.

CONCLUSION

In patients with subacute facial palsy, dynamic reanimation of the orbicularis oculi muscle with concomitant static interventions provides lasting corneal protection not seen in patients who receive solely static interventions.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Masseteric-Facial Nerve Anastomosis: Surgical Techniques and Outcomes-A Pilot Indian study

Masseteric-facial anastomosis has gained popularity in recent days compared to the facial-hypoglossal anastomosis. Masseteric nerve has numerous advantages like its proximity to the facial nerve, stronger motor impulse, its reliability, low morbidity in harvesting and sacrificing the nerve and faster re-innervation that is achievable in most patients. The present case series demonstrate the surgical technique and the effectiveness of the masseteric nerve as donor for early facial reanimation. Between January 2017 and February 2019, 6 patients (2 male, 4 female) with iatrogenic unilateral complete facial paralysis (grade VI, House Brackmann scale) who underwent masseteric-facial nerve anastomosis were included in the study. The time interval between the onset of paralysis and surgery ranged from 4 to 18 months (mean 8.5 months). In all patients pre-operative electromyography had facial mimetic muscle fibrillation potentials. All patients underwent end to end anastomosis except for one patient where greater auricular interposition graft was used. In all cases, the facial muscles showed earliest sign of recovery at 2-5 months. These movements were first noticed on the cheek musculature when the patients activated their masseter muscle. Eye movements started appearing at 6-9 months (in 3 cases) and forehead movements at 18 months (in 1 case). According to the modified House-Brackmann grading scale, one patient had Grade I function, two patients had Grade II function, and three had Grade V function. There was no morbidity except one patient who underwent interposition graft had numbness in the ear lobule. None of the patients could feel the loss of masseteric nerve function. Masseteric facial nerve anastomosis is a versatile, powerful early facial dynamic reanimation tool with almost negligible morbidity compared to other neurotization procedures for patients with complete facial nerve paralysis.

Masseteric Nerve Transfer for Facial Nerve Paralysis: A Systematic Review and Meta-analysis

Importance

A review of the role of masseteric nerve transfer is needed to guide its use in facial reanimation.

Objective

To systematically review the available literature, and, when applicable, analyze the combined outcomes of masseteric nerve transfer to better define its role in reanimation and to guide further research.

Data Sources

Two independent researchers conducted the review using PubMed-NCBI and Scopus literature databases for studies on masseteric nerve transfer for facial nerve paralysis.

Study Selection

Studies that examined masseter nerve transfer with additional cranial nerve transposition/coaptation or muscle flap were excluded.

Data Extraction and Synthesis

Literature review and data extraction followed established PRISMA guidelines. Two researchers extracted data independently.

Main Outcomes and Measures

The main planned outcomes for the study were quantitative results of facial nerve movement after nerve transfer including oral commissure movement and time to nerve recovery.

Results

A total of 13 articles met inclusion criteria with a total of 183 patients undergoing masseteric nerve transfer. From those studies, there were a total of 183 patients who underwent masseteric nerve transfer. There were 85 men and 98 women with a mean (SD) age of 43 (12.2) years and mean (SD) follow up examination after surgery of 22 (7.6) months. Mean (SD) duration of nerve paralysis was 14 (6) months. Most common cause of paralysis was cerebellopontine angle tumors (81%). Six studies coapted the masseteric nerve to the main facial nerve trunk, whereas 7 used distal branches (buccal or zygomatic). Four studies used interposition nerve grafts with great auricular nerve. Two measures, improvement in oral commissure excursion and length from reanimation to facial movement, were measured consistently across the studies. Pooled analysis showed time from surgery to first facial movement, described in 10 studies, to be 4.95 months (95% CI, 3.66 to 6.24). Distal branch coaptation improved time to recovery vs main branch coaptation, 3.76 vs 5.76 months (95% CI, -0.33 to 4.32), but mean difference was not significant. The use of interposition graft significantly delayed time of nerve recovery, 6.24 vs 4.06 months (95% CI, 0.20 to 4.16). When controlled for main trunk coaptation only, interposition nerve graft delayed recovery but difference was no longer statistically significant, 6.24 vs 4.75 months (95% CI, -0.94 to 3.92). Reported complications were minor and rare occurring in only 6.5% (12 of 183) of patients.

Conclusions and Relevance

The masseteric nerve was found to be a good option for nerve transfer in this patient population, and showed favorable results in both time to nerve recovery and improvement in oral commissure excursion.

Level of Evidence

NA.

Facial Nerve Trauma: Clinical Evaluation and Management Strategies

The field of facial paralysis requires the reconstructive surgeon to apply a wide spectrum of reconstructive and aesthetic principles, using a comprehensive array of surgical tools, including microsurgery, peripheral nerve surgery, and aesthetic facial surgery on the road to optimize patient outcomes. The distinct deficits created by different anatomical levels of facial nerve injury require a fundamental understanding of facial nerve anatomy. Palsy duration, followed by location and mechanism, will determine mimetic muscle salvageability, by means of either direct repair, grafting, or nerve transfers, whereas longer palsy durations will necessitate introducing a new neuromuscular unit, whether by muscle transfer or free functional muscle transplant. A thorough history, physical examination, and basic understanding of ancillary studies, emphasizing palsy duration, location, and mechanism of injury, are critical in evaluation, prognostication, and treatment strategies in traumatic facial palsy patients. The importance of ancillary and aesthetic procedures cannot be overstated. Although these do not provide motion, they constitute essential tools in the treatment of facial paralysis, providing both protective and improved aesthetic outcomes, yielding the highest impact in final surgeon and patient satisfaction, bringing our patients to smile not only on the outside, but also on the inside.

Anatomical study of the masseteric and obturator nerves: Application to face transplant and reanimation procedures

The masseteric nerve (MN) and the anterior branch of the obturator nerve (ON) that innervate the transferred gracilis muscle have proved highly efficient for reanimating paralyzed facial muscles when muscle transfer is required. Previous researchers have published the total axonal load for myelinated fibers in both nerves. However, the real motor axonal load has not been established. We performed the study on 20 MN and 13 ON. The segments of the MN and the ON were embedded in paraffin, sectioned at 10 μm, and stained following a standard immunohistochemical procedure using anti-choline acetyltransferase to visualize the motor fibers. The MN has a higher axonal load than the ON. There were statistically significant differences between the axonal load of the proximal segment of the MN and the ON. These findings confirm that end-to-end anastomoses between the MN and the ON should preferably use the proximal segment. However, MN neurotomy should ideally be performed between the proximal and distal segments, preserving innervation to the deep fascicles. Our results show that the MN is ideal as a donor motor nerve for reinnervating transplanted muscle for dynamic reanimation of the paralyzed face. The neurotomy should ideally be performed between the first and second collateral branches of the MN. Clin. Anat. 32:612-617, 2019. © 2019 Wiley Periodicals, Inc.

A comparative retrospective study: hypoglossofacial versus masseterofacial nerve anastomosis using Sunnybrook facial grading system

INTRODUCTION

The aim of our study is to compare the functional results between two surgical techniques for reanimation of facial paralysis: hypoglossal-to-facial versus masseteric-to-facial nerve anastomosis.

METHODS

This is a retrospective study of 13 patients treated for complete facial paralysis in two medical tertiary centers. The patients were classified into two groups. First group: masseteric-to-facial nerve anastomosis. Second group: hypoglossofacial nerve anastomosis. Sunnybrook facial grading system was used to evaluate the functional results. The mean scores were compared using Mann-Whitney test. The correlation between the age at surgery, the delay in time from the onset of the facial paralysis to the time of surgery and the results of Sunnybrook scores was studied using correlation and linear regression.

RESULTS

No significant statistical difference was found between the mean of total score of the two groups (first group = 38 ± 4.898, second group = 37.83 ± 4.956). All the patients treated by hypoglossofacial nerve anastomosis presented with hemiglossal atrophy. We found slight superiority for the masseterofacial nerve anastomosis in dynamic movements, whereas at rest the hypoglossofacial anastomosis is slightly better. All the differences were not statistically significant. No correlation was found between the age at surgery (age range included 32-73 years) and post-operative results. No correlation was found between the delays up to 24 months from the onset of the facial paralysis and post-operative results.

CONCLUSION

Our study showed that both types of anastomosis are effective with comparable results. The masseterofacial nerve anastomosis is preferred when possible to avoid the hemiglossal atrophy and its complications.

Facial Paralysis Discussion and Debate

This article examines 6 questions about facial paralysis answered by 3 experts in their field of facial plastic surgery. The topics covered include routine assessment, neuromuscular training, nonsurgical management, and the future of this field. All the authors answered these questions in a "How I do it" manner to provide the reader with a true understanding of their thoughts and techniques. This article provides a practical resource to all physicians and practitioners treating patients with facial paralysis on some of the most common questions and issues.

Use of the masseteric nerve to treat segmental midface paresis

Segmental midface paresis with or without synkinesis reflects incomplete recovery from Bell's palsy, operations on the cranial base or parotid, or trauma, in 25%-30% of cases. To correct the deficit, the masseteric nerve was used to deliver a powerful stimulus to the zygomatic muscle complex, with the addition of a cross-face sural nerve graft to ensure more spontaneous smiling. By doing this, the orbicularis oculi muscle continues to have an appropriate stimulus from the facial nerve, and the zygomatic muscle complex is separately innervated, which considerably reduces synkinesis between the two muscle compartments. For those patients with muscular contractures of the midface, the new healthy neural stimulus relaxes muscles at rest. From January 2011 to March 2017, 20 patients presented with segmental facial paresis of the midface and were operated on using this new technique. All patients were evaluated before and after operation using Clinician-Graded Electronic Facial Paralysis Assessment (eFACE), and they showed considerable postoperative improvements in static, dynamic, and synkinetic variables. Our proposed use of the masseteric nerve to treat segmental facial paresis produces favourable results, but our initial data require confirmation by further studies.

Mixed facial reanimation technique to treat paralysis in medium-term cases

Recent facial paralyses, in which fibrillations of the mimetic muscles are still detectable by electromyography (EMG), allow facial reanimation based on giving new neural stimuli to musculature. However, if more time has elapsed, mimetic muscles can undergo irreversible atrophy, and providing a new neural stimulus is simply not effective. In these cases function is provided by transferring free flaps into the face or transposing masticatory muscles to reinstitute major movements, such as eyelid closure and smiling. In a small number of cases, patients affected by paralysis are referred late - more than 18 months after onset. In these cases, reinnervating the musculature carries a high risk of failure because some or all of the mimetic muscles may atrophy irreversibly while axonal ingrowth is taking place. A mixed reanimation technique to address this involves a neurorrhaphy between the masseteric nerve and a facial nerve branch for the orbicularis oculi, to ensure a stronger innervation to that muscle, associated with the transposition of the temporalis muscle to the nasiolabial sulcus. This gives good symmetry in the rest of the midface, while smiling movement is achievable, but not guaranteed. This one-time facial reanimation is particularly indicated for those who refuse major free-flap surgery or when that may be risky, as in previously operated and irradiated fields. More extensive procedures based on utilizing a free flap to recover smiling, while adding a cross-face nerve graft to restore blinking, may be proposed for motivated patients. Between 2010 and 2015, five patients affected by complete unilateral facial palsy underwent this technique in the Maxillofacial Surgery Department, San Paolo Hospital (Milan, Italy). Symmetry of the middle-third of the face at rest and recovery of smiling was quite good. Complete voluntary eyelid closure was obtained in all cases. Combining temporalis flap rotation and a masseteric-to-orbicularis-oculi-facial-nerve branch neurorrhaphy seems to be a valid solution for those medium-term referred patients.

Differential Reanimation of the Midface and Lower Face Using the Masseteric and Hypoglossal Nerves for Facial Paralysis

BACKGROUND

Hypoglossal nerve transfer is frequently employed to reanimate the paralyzed facial muscles after irreversible proximal facial nerve injury. However, it can cause significant postoperative synkinesis because it involves the reinnervation of the whole mimetic musculature using a single motor source.

OBJECTIVE

To describe our experience with differential reanimation of the midface and lower face using separate motor sources in patients with short-term facial paralysis after brain surgery.

METHODS

Seven patients underwent combined nerve transfer (the masseteric nerve to the zygomatic branch and the hypoglossal nerve to the cervicofacial division of the facial nerve) and cross-facial nerve grafting with the aim of achieving a spontaneous smile. The median duration of paralysis before surgery was 7 mo and follow-up ranged from 7 to 31 mo (mean: 18 mo). For evaluation, both physical examination and video analysis were performed.

RESULTS

In all patients, reanimation of both the midface and the lower face was successful. A nearly symmetrical resting lip was achieved in all patients, and they were able to voluntarily elevate the corners of their mouths without visible synkinesis and to close their eyes while biting. No patient experienced impairment of masticatory function or tongue atrophy.

CONCLUSION

Differential reanimation of the midface and lower face with the masseteric and hypoglossal nerves is an alternative method that helps to minimize synkinetic mass movement and morbidity at the donor site.