The effect of increasing motor end-plate innervation on smile activation in acute and early facial palsy.

While it has been over half a century since primary cross-facial nerve grafting was first described for facial reanimation, the outcome of this procedure, remains inconsistent and provide lesser smile excursion when compared to the likes of the masseteric nerve. However, the latter itself has limitations in terms of the lack of spontaneity and resting tone. While combinations have been attempted more proximally, we ask the question as to whether more distal nerve transfers with vascularized nerve grafts are a better option. In a retrospective review of clinical practice at our institute, 16 consecutive patients had single, double, and finally triple distal nerve transfers, close to the target facial muscle to reinnervate the motor endplates directly, over a 6-year period (2018-23). All patients had the onset of facial palsy within 18 months. Statistical analysis of the comparison between three sub-cohorts was performed using student's t-test and one-way ANOVA, respectively. Qualitatively, masseteric neurotization of a single facial nerve branch translated into smile improvement in 50% of cases, as opposed to all cases of double- and triple-neurotization of the smile muscles. In terms of upper lip elevation, single neurotization showed improvement in 25% of cases, double-neurotization in 40% of cases and triple-neurotization in 100% of cases. Upper lip elevation was also significantly better in those who had a vascularized cross-facial nerve graft (Student's t-test <0.05). In summary, increasing neural input to the motor endplates of smile muscles can significantly improve smile activation, in acute flaccid facial palsies.

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.

Facial Aberrant Reinnervation Syndrome Following Facial Nerve Injury and Recovery.

A common sequela of peripheral nerve injury is aberrant regeneration and recovery. Aberrant regeneration of injured motor nerves can affect all aspects of the nerve circuit from the motor cortex to the target muscle. A more comprehensive term for the symptoms that develop after aberrant motor neuromuscular reinnervation is aberrant reinnervation syndrome (ARS). Injury to the facial nerve followed by aberrant reinnervation results in a spectrum of symptoms that has been called many things in the literature. The authors support that this commonly encountered sequela of facial nerve injury be called facial aberrant reinnervation syndrome (FARS), a term that is more descriptive of the underlying pathophysiology and more inclusive of the clinical symptoms: facial synkinesis, facial muscle hypertonicity, and facial muscle spasm/twitching, which occur following facial nerve injury and recovery. In the following article, we present the clinical manifestations and sequelae of facial nerve injury and recovery and briefly discuss our evolving understanding of the pathophysiology and treatment of FARS.

Functional Outcomes of Single-Stage Facial Reanimation Surgery With Radical Parotidectomy.

OBJECTIVES: Facial nerve sacrifice during radical parotidectomy can impair quality of life. This study assessed the effectiveness of single-stage facial reanimation surgery performed concurrently with radical parotidectomy in restoring facial function. METHODS: A retrospective analysis was conducted on patients who underwent single-stage facial reanimation combined with radical parotidectomy. The techniques employed included selective reinnervation and orthodromic temporalis tendon transfer. Outcomes were evaluated using the modified House-Brackmann and Terzis grading systems, Emotrics facial assessment, and the Facial Disability Index (FDI). RESULTS: Among the 13 patients studied (median age, 54 years; 69% male), 10 underwent selective reinnervation. Of these, nine patients demonstrated improvement, achieving House-Brackmann grade III and Terzis grade 4 or 5. The other three patients underwent tendon transfer and achieved moderate functional outcomes. Emotrics analysis revealed balanced facial symmetry in the selective reinnervation group. Furthermore, FDI scores indicated satisfactory physical and social/well-being functions. CONCLUSION: Single-stage facial reanimation effectively restores facial function in patients undergoing radical parotidectomy. This approach offers meaningful benefits in the early recovery of facial function.

Masseteric Atrophy Following Masseteric Nerve Transfer: Radiographic Findings of Asymmetry in the Paralyzed Face?

OBJECTIVES: To characterize the effect of facial reanimation using masseteric nerve transfer on the masseter muscle itself, examining whether there is any demonstrable atrophy postoperatively. METHODS: Electronic medical records of adult patients who underwent facial reanimation using masseteric nerve transfer at our institution over a 15-year period were reviewed. To account for the impact of postoperative radiation, randomly selected patients who underwent radical parotidectomy without nerve transfer and received postoperative radiation served as controls in a 1:1 fashion against those who underwent masseteric nerve transfer with postoperative radiation. RESULTS: Twenty patients were identified who underwent masseteric nerve transfer and had sufficient pre- and postoperative imaging to assess masseter volume (mean age 58.2, 60% female). Of the four patients who did not receive postoperative radiation, each demonstrated masseteric atrophy on the side of their nerve transfer, with a mean reduction in masseter volume of 20.6%. The remaining 16 patients were included in the case-control analysis accounting for radiation. When compared with controls, those in the study group were found to have a statistically significant difference in atrophy (p = 0.0047) and total volume loss (p = 0.0002). The overall reduction in masseter volume in the study group was significantly higher compared with the control group, at 41.7% and 16.6%, respectively (p = 0.0001). CONCLUSION: Facial reanimation utilizing masseteric nerve transfer appears to result in atrophy of the denervated masseter when compared with the contralateral muscle. This volume deficit may lead to further facial asymmetry for patients undergoing comprehensive reanimation surgery. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Changes in Perceived Emotions in Facial Paralysis Patients After Depressor Anguli Oris Excision.

OBJECTIVES: Depressor anguli oris (DAO) excision can improve clinician-graded, objective, and patient-reported smile outcomes in patients with nonflaccid facial paralysis (NFFP). However, no prior research has studied changes in perceived emotions after surgery. This study quantifies changes in perceived emotions with smiling after DAO excision in the largest case series presented to date. METHODS: Prospectively collected data from patients with NFFP who underwent DAO excision at a tertiary care facial nerve center were reviewed. Patient-reported, clinician-graded, and objective smile metrics were compared before and after surgery. Videos of faces at rest and while smiling were analyzed by artificial intelligence-derived facial expression analysis software to quantify perceived emotions. RESULTS: Sixty-eight patients underwent isolated DAO excision between August 2021 and August 2023. Patients conveyed significantly more perceived happiness with smile and at rest after surgery (p < 0.001 and p = 0.012, respectively). DAO excision improved oral commissure excursion (p < 0.001), dental show (p < 0.001), and smile angle (p < 0.001) symmetry. Patients reported significant improvements in smiling and social function after surgery. CONCLUSIONS: This study demonstrates DAO excision increases perceived happiness conveyed by patients with NFFP while smiling and at rest. It confirms improved objective, clinician-graded, and patient-reported smile outcomes after surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:4028-4035, 2024.

Is pre-operative electromyography a reliable tool in differentiating acute and chronic facial palsy? A preliminary evaluation in patients treated with triple innervation facial reanimation.

Electromyographic evaluation is a reliable tool for confirming facial palsy and assessing its severity. It allows differentiating facial paresis and paralysis, and further distinguishes acute palsies, still showing muscle fibrillations, from chronic cases. This article aims to show that EMG fibrillations might represent a better criterion to differentiate acute and chronic palsies than the standard 18-24 months' cut-off usually employed for classification and treatment purposes. We performed a cohort study using the eFACE tool for comparing triple innervation facial reanimation results in patients with EMG fibrillation treated <12 months, 12-18 months, and >18 months from paralysis onset. Patients showed a statistically significant post-operative improvement in all eFACE items, both in the whole sample and in the three groups. Only the deviation from the optimal score for the gentle eye closure item in group 2 didn't reach statistical significance (p = 0.173). The post-operative results were comparable in the three groups, as the Kruskal-Wallis test showed a difference only for the platysmal synkinesis item scores, which were significantly lower in group 3 (p = 0.025).

A Novel Approach to Facial Reanimation and Restoration Following Radical Parotidectomies.

Background: Parotidectomies are indicated for a variety of reasons. Regardless of the indication for surgery, facial reanimation may be required because of facial nerve sacrifice or iatrogenic damage. In these cases, facial restoration performed concurrently with ablative surgery is considered the gold standard, and delayed reanimation is usually not attempted. Methods: A retrospective review of all patients who underwent parotidectomies from 2009 to 2022 in a single institution was performed. Indications, surgical techniques, and outcomes of an algorithmic template were applied to these cases using the Sunnybrook, Terzis scores, and Smile Index. A comparison was made between immediate vs. late repairs. Results: Of a total of 90 patients who underwent parotidectomy, 17 (15.3%) had a radical parotidectomy, and 73 (84.7%) had a total or superficial parotidectomy. Among those who underwent complete removal of the gland and nerve sacrifice, eight patients (47.1%) had facial restoration. There were four patients each in the immediate (n = 4) and late repair (n = 4) groups. Surgical techniques ranged from cable grafts to vascularized cross facial nerve grafts (sural communicating nerve flap as per the Koshima procedure) and vascularized nerve flaps (chimeric vastus lateralis and anterolateral thigh flaps, and superficial circumflex perforator flap with lateral femoral cutaneous nerve). Conclusions: The algorithm between one technique and another should take into consideration age, comorbidities, soft tissue defects, presence of facial nerve branches for reinnervation, and donor site morbidity. While immediate facial nerve repair is ideal, there is still benefit in performing a delayed repair in this algorithm.

Quality of life after surgical treatments for facial palsy: A systematic review and meta-analysis.

BACKGROUND: Facial palsy profoundly affects patients' quality of life (QoL). We evaluated the effect of various surgical procedures on QoL using patient-reported outcome measures (PROMs) to provide evidence-based recommendations for improved care. METHODS: Embase, Medline, Web of Science, Cochrane, and CINAHL were searched for studies on QoL in patients with facial palsy who had undergone reconstructive surgery with preoperative and postoperative data from validated PROMs. After conducting the quality assessment, data were subtracted from the articles. Meta-analyses of subgroups were performed when study outcomes where compatible. RESULTS: Incorporating 24 studies (522 patients), our systematic review revealed consistent and significant QoL improvements following diverse reconstructive surgical procedures. CONCLUSIONS: Our systematic review and meta-analysis showed the positive effects of different reconstructive surgical procedures on QoL of patients with facial palsy. These results support clinicians to better inform patients about their potential outcomes, optimizing informed and shared decision-making and ultimately improving overall QoL in patients with facial palsy.

Restoring the spontaneous smile through free functional muscle transfer. A systematic review and meta-analysis of the last twenty years' experience.

BACKGROUND: The recovery of the spontaneous smile has become a primary focus in facial reanimation surgery and its major determinant is the selected neurotizer. We aimed to compare the spontaneity outcomes of the most preferred neurotization methods in free functional muscle transfer for long-standing facial paralysis. METHODS: The Embase, Ovid Medline, and PubMed databases were queried with 21 keywords. All clinical studies from the last 20 years reporting the postoperative spontaneity rate for specified neurotization strategies [cross-face nerve graft (CFNG), contralateral facial nerve (CLFN), motor nerve to the masseter (MNM), and dual innervation (DI)] were included. A meta-analysis of prevalence was performed using Freeman-Tukey double arcsine transformation, I2 statistic, and generic inverse variance with a random-effects model. Risk Of Bias In Non-randomized Studies of Interventions and Newcastle-Ottawa scale were used to assess bias and study quality. RESULTS: The literature search produced 2613 results and 473 unique citations for facial reanimation. Twenty-nine studies including 2046 patients were included in the systematic review. A meta-analysis of eligible data (1952 observations from 23 studies) showed statistically significant differences between the groups (CFNG: 0.94; 95% confidence interval [CI], 0.76-1.00, CLFN: 0.91; 95% CI, 0.49-1.00, MNM: 0.26; 95% CI, 0.05-0.54, DI: 0.98; 95% CI, 0.90-1.00, P < 0.001). In pairwise comparisons, statistically significant differences were found between MNM and other neurotization strategies (P < 0.001 in CFNG compared with MNM, P = 0.013 for CLFN compared with MNM, P < 0.001 for DI compared with MNM). CONCLUSIONS: DI- and CLFN-driven strategies achieved the most promising outcomes, whereas MNM showed the potential to elicit spontaneous smile at a lower extent. Our meta-analysis was limited primarily by incongruency between spontaneity assessment systems. Consensus on a standardized tool would enable more effective comparisons of the outcomes.

Future treatment options for facial nerve palsy: a review on electrical stimulation devices for the orbicularis oculi muscle.

Facial nerve palsy can cause diminished eyelid closure (lagophthalmos). This occurs due to functional deficits of the orbicularis oculi muscle, potentially leading to sight-threatening complications due to corneal exposure. Current management options range from frequent lubrication with eye drops, to the use of moisture chambers and surgery. However, achieving functional restoration may not always be possible. Recent efforts have been directed towards the support of orbicularis oculi muscle function through electrical stimulation. Electrical stimulation of the orbicularis oculi muscle has been demonstrated as feasible in human subjects. This article offers a comprehensive review of electrical stimulation parameters necessary to achieve full functionality and a natural-looking eye blink in human subjects. At present, readily available portable electrical stimulation devices remain unavailable. This review lays the foundation for advancing knowledge from laboratory research to clinical practice, with the ultimate objective of developing a portable electrical stimulation device. Further research is essential to enhance our understanding of electrical stimulation, establish safety standards, determine optimal current settings, and investigate potential side effects.

Research trends and perspectives on immediate facial reanimation in radical parotidectomy (Review).

For patients diagnosed with advanced malignant parotid tumour, radical parotidectomy with facial nerve sacrifice is part of the treatment. Multiple surgical techniques have been developed to cure facial paralysis in order to restore the function and aesthetics of the face. Despite the large number of publications over time on facial nerve reanimation, a consensus on the timing of the procedure or the donor graft selection has remained to be established. Therefore, the aim of the present study was to conduct a bibliometric analysis to identify and analyse scientific publications on the reconstruction of the facial nerve of patients who underwent radical parotidectomy with facial nerve sacrifice. The analysis on the topic was conducted using the built-in tool of the Scopus database and VOSviewer software. The first 100 most cited articles were separately reviewed to address the aim of the study. No consensus was found regarding the recommended surgical techniques for facial nerve reanimation. The most used donor cranial nerves for transfer included the following: Masseteric branch of the V nerve, contralateral VII nerve with cross-face graft, the XI nerve and the XII nerve. The best timing of surgery is also controversial depending on pre-exiting pathology and degree of nerve degeneration. However, most of the clinical experience suggests facial nerve restoration immediately after the ablative procedure to reduce complications and improve patients' quality of life.

Extra- and intramuscular innervation of the masseter: Implications for facial reanimation.

PURPOSE: Irreversible facial paralysis results in significant functional impairment. The motor nerve to the masseter is a reconstructive option, but despite its clinical importance, there are few parametric anatomic studies of the masseteric nerve. The purpose of this study was to investigate the extra- and intramuscular innervation of the masseter in 3D to determine the relationship of the nerve to the muscle heads and identify landmarks to aid identification. MATERIALS AND METHODS: The nerve was dissected throughout its entire course in eight formalin-embalmed cadaveric specimens (mean age 84.9 ± 12.2 years). The nerve was digitized at 1-2 mm intervals using a MicroScribe™ digitizer and modeled in 3D in Autodesk® Maya®. RESULTS: Two or three extramuscular nerves were found to enter the deep head (DH) of the masseter: one main "primary" nerve (n = 8) and one (n = 4) or two (n = 4) smaller primary nerve(s). The main primary nerve supplied both the deep and superficial heads, whereas the smaller primary nerve(s) only supplied the DH. Surgical landmarks for masseter nerve localization were quantified. CONCLUSIONS: Comprehensive mapping of the innervation of the masseter muscle throughout its volume revealed neural partitioning that could provide a basis for safety planning for muscle flaps and donor nerve identification and explain why masseter functional loss is not incurred by donor nerve sacrifice. Quantified landmarks correlate to previous studies and support the constant anatomy of this nerve. Our results provide a basis to optimize surgical approaches for donor nerve and muscle flap surgery.

Age-related outcomes of facial reanimation surgery using gracilis free functional muscle transfer innervated by the masseteric nerve: A retrospective cohort study.

BACKGROUND: The free functional muscle gracilis transfer is an established approach in facial reanimation surgery; however, the significance of its neurotization and the patient's age is still inconclusive. Several donor nerves are available for facial reanimation using the free functional gracilis muscle transfer. OBJECTIVE: This retrospective cohort study investigates whether the masseteric nerve is an equally reliable donor nerve in both older and younger patients. METHODS: We included 46 patients (13-71 years, male and female) who underwent nerve-to-masseter (NTM)-driven free functional muscle transfer (FFMT) between January 2008 and December 2019. Patients were distributed into three cohorts according to their age at surgery. We assessed the facial symmetry before and after surgery using the pupillo-modiolar angle. Commissure height and excursion deviation were measured with the Emotrics software. Patient-reported outcome measurements were taken using the Facial Clinimetric Examination (FaCE) scale. RESULTS: All patients had successful flap innervation, except for one patient in the middle-aged cohort (31-51 years). The postoperative facial symmetry at rest, smiling, and laughing was analyzed with the pupillo-modiolar angle and the Emotrics software and showed similar results between all cohorts. The FaCE scale showed similar scores for the middle-aged (31-51 years) cohort and the senior cohort (52-71 years). The social function score in the senior cohort was higher than in the middle-aged cohort, without statistical significance. One patient in the middle-aged (31-51 years) cohort and the senior cohort (52-71 years), respectively, underwent emergency revision due to impaired flap perfusion and could be salvaged. CONCLUSIONS: NTM-driven FFMT for facial reanimation is a safe and reliable procedure across all age groups of patients.

The surgical anatomy of the deep temporal nerve: A cadaveric study.

BACKGROUND: The aims of this study were to investigate the surgical anatomy of the deep temporal nerve (DTN) and find (fixed/static) anatomical landmarks that could be used during surgery to localise the DTN branches. METHODS: Ten hemifaces of Dutch cadavers were dissected at the Department of Anatomy of the Radboudumc. Landmarks and measurements of interest were number of branches of the DTN, distance from the tragus to the DTN, and distance from the cranial and caudal parts of the posterior root of the zygomatic bone until the DTN. RESULTS: In this cadaveric study, 10 hemifaces were dissected (male, n = 6 [60%]; female, n = 4 [40%]) with an equal left/right side division. The number of deep temporal branches varied from 2 (30%) to 3 (70%) per side. The mean distance to the tragus varied from 40 to 53 mm, with a mean distance of 44.3 ± 4.4 mm. The mean distance from the cranial part of the posterior root of the zygomatic bone to the DTN varied from 29 to 35 mm, with a mean distance of 31.3 ± 2.1 mm. The distance from the caudal part of the posterior root of the zygomatic bone to the DTN varied from 8 to 17 mm, with a mean distance of 13.4 ± 3.4 mm. CONCLUSION: This study investigated the surgical anatomy and landmarks used for identification of the DTN and its branches. It suggested using firm landmarks for nerve identification, such as the posterior root of the cranial and/or the caudal zygomatic bone.

A Rare Case of Muco-epidermoid Carcinoma Parotid in a 6-Year-Old Girl and Review of Literature.

Mucoepidermoid carcinoma (MEC) is the commonest malignant salivary gland tumor affecting the parotid gland in adults and children. In children and adolescents, there is a peak incidence in the second decade. We came across a 6-year-old girl with intermediate-grade MEC parotid gland, which is very unusual below 10 years of age. A global literature search revealed only 3 other similar cases in children below 10 years of age. She presented with a 2-year history of left parotid gradually increasing hard swelling involving the overlying skin and underlying sternocleidomastoid muscle which was confirmed on a contrast-enhanced computed tomography (CECT) scan of the face and neck as well as a core biopsy to be a MEC left parotid. The patient underwent a left radical parotidectomy sacrificing the main trunk of the facial nerve while carefully preserving its distal branches along with a left selective neck dissection (SND) followed by facial reanimation using primary neurorrhaphy. Histopathology confirmed an intermediate-grade MEC pT4aN2bMx with close deep lobe margin warranting adjuvant radiotherapy. Albeit very rare, salivary gland neoplasms may occur in children in the first decade of life. Appropriate planning regarding oncological resection with/without facial reanimation, appropriate rehabilitation followed by adjuvant treatment based on histopathology ensures a good prognosis.

Optimizing the results of facial animation surgery: Botulinum toxin injection into free functional gracilis flap transfer.

Although neuromuscular gracilis transplantation is the best choice for facial reanimation in patients with congenital or inveterate palsy, the results are not completely satisfactory. Ancillary procedures developed to achieve better symmetry of the smile and reduce the hypercontractility of the transplanted muscle have been reported. However, the intramuscular injection of botulinum toxin has not been described for this purpose. Patients undergoing gracilis injections of botulinum toxin after facial reanimation surgery between September 1, 2020, and June 1, 2022, were retrospectively enrolled in this study. We collected photographs taken before and 20-30 days after injection and compared the symmetry of the face using software. Nine patients with a mean age of 23.56 years (range, 7-56 years) were enrolled. Reinnervation of the muscle was provided by the contralateral healthy facial nerve via a sural cross-graft (four patients), by the ipsilateral masseteric nerve (three cases), and by the contralateral masseteric and facial nerve (two). Using Emotrics software, we identified differences in the commissure excursion discrepancy of 3.82 mm, the smile angle discrepancy of 0.084°, and the dental show discrepancy of 1.49 mm; the average difference in the commissure height deviation was 2.26 mm (P = 0.02), and those in the upper- and lower-lip height deviation were 1.05 mm and 1.49 mm, respectively. Gracilis injection of botulinum toxin after gracilis transplantation is a safe and feasible procedure that could be applicable to all patients with asymmetric smiles related to excessive transplant contraction. It yields good esthetic results with little to no related morbidity.

Artificial intelligence-based numerical analysis of the quality of facial reanimation: A comparative retrospective cohort study between one-stage dual innervation and single innervation.

This study aimed to investigate the difference in facial reanimation surgery using functional gracilis muscle transfer between the masseteric nerve alone and its combined use with cross face nerve graft (CFNG), which has not been explored before. A novel analysis method based on artificial intelligence (AI) was employed to compare the outcomes of the two approaches. Using AI, 3-dimensional facial landmarks were extracted from 2-dimensional photographs, and distance and angular symmetry scores were calculated. The patients were divided into two groups, with Group 1 undergoing one-stage CFNG and masseteric nerve dual innervation, and Group 2 receiving only masseteric nerve. The symmetry scores were obtained before and 1 year after surgery to assess the degree of change. Of the 35 patients, Group 1 included 13 patients, and Group 2 included 22 patients. The analysis revealed that, in the resting state, the change in the symmetry score of the mouth corner showed distance symmetry (2.55 ± 2.94, 0.52 ± 2.75 for Group 1 and Group 2, respectively, p = 0.048) and angle symmetry (1.21 ± 1.43, 0.02 ± 0.22 for Group 1 and Group 2, respectively, p = 0.001), which were significantly improved in Group 1, indicating a more symmetric pattern after surgery. In the smile state, only the angle symmetry was improved more symmetrically in Group 1 (3.20 ± 2.38, 1.49 ± 2.22 for Group 1 and Group 2, respectively, p = 0.041). Within the limitations of the study it seems that this new analysis method enabled a more accurate numerical symmetry score to be obtained, and while the degree of mouth corner excursion was sufficient with only the masseteric nerve, accompanying CFNG led to further improvement in symmetry in the resting state.