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.

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.

The evolution of facial reanimation techniques.

This review article provides an updated discussion on evidence-based practices related to the evaluation and management of facial paralysis. Ultimately, the goals of facial reanimation include obtaining facial symmetry at rest, providing corneal protection, restoring smile symmetry and facial movement for functional and aesthetic purposes. The treatment of facial nerve injury is highly individualized, especially given the wide heterogeneity regarding the degree of initial neuronal insult and eventual functional outcome. Recent advancements in facial reanimation techniques have better equipped clinicians to approach challenging patient scenarios with reliable, effective strategies. We discuss how technology such as machine learning software has revolutionized pre- and post-intervention assessments and provide an overview of current controversies including timing of intervention, choice of donor nerve, and management of nonflaccid facial palsy with synkinesis. We highlight novel considerations to mainstay conservative management strategies and examine innovations in modern surgical techniques with a focus on gracilis free muscle transfer. Innervation sources, procedural staging, coaptation patterns, and multi-vector and multi-muscle paddle design are modifications that have significantly evolved over the past decade.

Mining the Twittersphere: Insights about Public Interest in Facial Reanimation Surgery from a Decade of Twitter Data.

Background With 500 million tweets posted daily, Twitter can provide valuable insights about public discourse surrounding niche topics, such as facial paralysis surgery. This study aims to describe public interest on Twitter relating to facial paralysis and facial reanimation surgery over the last decade. Methods Tweets containing the keywords "facial paralysis" and "Bell's palsy" posted between January 1, 2009, and January 1, 2019, were collected using Twitter Scraper. Tweets were screened by keywords relating to facial paralysis, and usage of these terms trended over time. Logistic regression was used to identify correlations between the quantity of publications per year and these terms posted on Twitter. Results 32,880 tweets were made during the study period, with no significant difference in the number of tweets per year. A very strong ( r = 0.8-1.0) positive correlation was found between time and frequency of the term "plastic surgery" and "transfer" ( p < 0.05). A strong ( r = 0.60-0.79) correlation was found between time and frequency for the following terms: "facial reanimation," "gracilis," "masseter," "plastics," "transplant" ( p < 0.05). A total of 619 studies with the keyword "facial reanimation" were published in PubMed within the study period. A very strong, positive correlation between publications per year and frequency was found for the terms "plastic surgery," "function" and "esthetic," and a strong, positive correlation was found for the "plastics," "transplant," "Botox," "surgery," "cosmetic," "aesthetic" and "injection" ( p < 0.05). Conclusions An increasing number of discussion about facial paralysis on Twitter correlates with increased publications and likely surgeon discourse on facial reanimation surgery, driving public interest.

Paediatric facial paralysis: An overview and insights into management.

The aim of this article is to provide an overview on paediatric facial paralysis, looking into aetiology, epidemiology, assessment and investigation and subsequent treatment options available. Facial paralysis describes the inability to activate the muscles of fascial expression. Overall, it affects 2.7 per 100 000 children under 10 years old and 10.1 per 100 000 children over 10 years old each year. There are many causes of facial paralysis and the outcomes and necessary treatments vary depending on the cause. The mainstays of medical management are corticosteroids and facial therapy; however, when the facial palsy persists, facial deformity surgery is an option to improve the facial symmetry, protect vision and recreate dynamic movement.

Comparison between VII-to-VII and XII-to-VII coaptation techniques for early facial nerve reanimation after surgical intra-cranial injuries: a systematic review and pooled analysis of the functional outcomes.

The surgical injury of the intracranial portion of the facial nerve (FN) is a severe complication of many skull base procedures, and it represents a relevant issue in terms of patients' discomfort, social interactions, risk for depression, and social costs. The aim of this study was to investigate the surgical and functional outcomes of the most common facial nerve rehabilitation techniques. The present study is a systematic review of the pertinent literature, according to the PRISMA guidelines. Two different online medical databases (PubMed, Scopus) were screened for studies reporting the functional outcome, measured by the House-Brackman (HB) scale, and complications, in FN early reanimation, following surgical injuries on its intracranial portion. Data on the VII-to-VII and XII-to-VII coaptation, the surgical technique, the use of a nerve graft, the duration of the deficit, and complications were collected and pooled. The XII-to-VII end-to-side coaptation seems to provide higher chances for functional restoration (HB 1-3) than the VII-to-VII (68.8% vs 60.6%), regardless of the duration of the palsy deficit, the use or not of a nerve graft, and the use of stitches or glues. However, its complication rate was as high as 28.6%, and a second procedure is then often needed. The XII-to-VII side-to-end coaptation is the most effective in providing a functional outcome (HB 1-3), even though it is associated to a higher complication rate. Further trials are needed to better investigate this relevant topic, in terms of health-related social costs and patients' quality of life.

The role of gold weight implants in the management of paralytic lagophthalmos.

BACKGROUND: The study aims to evaluate the usage of gold weight implants and monitor complaints and comfort of patients. METHODS: A hundred and ninety-one implantations performed between January 2009 and January 2019 were analyzed. Seventy-eight patients included in this study The average age of the patients was 51.3 ± 14.5 years. Forty-five (57.7%) of them were male and 33 (42.3%) female. Patient satisfaction was measured with a questionnaire containing the most common complaints related to gold weight in the literature through telephone surveys. RESULTS: The average follow-up time was 74.5 months. Ninety-three-point-five percent of subjects had operational causes, among which the most widespread was acoustic neuroma (44.9%). The average time between facial paralysis and implantation was 141.1 days. Implantation was performed 26.6 days on average after acoustic neuroma surgery and 3.2 days on average after temporal zone malignancy surgery. Thirty-eight patients had their implants removed over either complication (n = 14) or recovery (n = 24). Recovery was the fastest after facial nerve decompression (mean= 4.75 ± 3.6 (2-10) months) and the slowest after 7-12 cranial nerve transfer (mean= 18.3 ± 8.2 (3-31) months). Twenty-six-point-nine percent (n = 21) of patients had complications, of which the most common was extrusion (n = 10). The overall satisfaction rate was 88.5% with the highest in visual acuity and the lowest in continuous requirement for artificial tear. DISCUSSION: The gold weight implantation is an effective, reversible, and easy procedure significantly reducing complaints regarding paralytic lagophthalmos. Early implementation may be beneficial for ocular complications. A dynamic facial reanimation could terminate need of implant.

Facial nerve management in patients with malignant skull base tumors.

INTRODUCTION: The course of the facial nerve through the cerebellopontine angle, temporal bone, and parotid gland puts the nerve at risk in cases of malignancy. In contrast to Bell's palsy, which presents with acute facial paralysis, malignancies cause gradual or fluctuating weakness. METHODS: We review malignancies affecting the facial nerve, including those involving the temporal bone, parotid gland, and cerebellopontine angle, in addition to metastatic disease. Intraoperative management of the facial nerve and long term management of facial palsy are reviewed. RESULTS: Intraoperative management of the facial nerve in cases of skull base malignancy may involve extensive exposure, mobilization, or rerouting of the nerve. In cases of nerve sacrifice, primary neurorrhaphy or interposition grafting may be used. Cranial nerve substitution, gracilis free functional muscle transfer, and orthodromic temporalis tendon transfer are management options for long term facial paralysis. CONCLUSION: Temporal bone, parotid gland, and cerebellopontine angle malignancies pose a tremendous risk to the facial nerve. When possible, the facial nerve is preserved. If the facial nerve is sacrificed, static and dynamic reanimation strategies are used to enhance facial function.

Long-term electrophysiological assessment after hypoglossal-facial anastomosis.

PURPOSE: To investigate and provide objective documentation of the possible differences in the axonal reinnervation process of facial muscles after hypoglossal-facial nerve anastomosis. Then, to search for the presence of the trigemino-hypoglossal reflex and determine whether it indicates better peripheral recovery. METHODS: Electrophysiological examination performed on 20 patients who had undergone VII-XII anastomosis, with follow-up periods of more than 2 years. RESULTS: The mean follow-up time after surgery was 4.1 ± 1.3 years (range 2-8 years). The degrees of axonal reinnervation for the orbicularis oculi (OOc) and orbicularis oris (OOr) were 46.91 ± 19.77 and 32.65 ± 14.85, respectively. And the difference between these muscles was statistically significant (p = 0.018) in favor of the OOc. In addition, R1 blink reflexes that were not followed by R2 components were observed in 30% of the patients. However, these 6 patients with short-latency potential did not differ from the others in terms of latency, the amplitude of compound muscle action potential (CMAP), and degree of axonal reinnervation (p > 0.05) at both muscles (OOc and OOr). CONCLUSION: The recoveries of the lower face and upper face are different after VII-XII anastomosis, and in our patients the OOc healed better. In addition, R1 blink reflexes that were not followed by R2 components were observed in 30% of the patients. However, the patients with these blink reflexes did not have better peripheral healing in their neuromuscular units, which suggests that the blink reflex is not an indicator for peripheral recovery.

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.

Long-Term Outcomes of Free Gracilis Muscle Transfer for Smile Reanimation in Children.

OBJECTIVE: To evaluate long-term outcomes of free gracilis muscle transfer (FGMT) for smile reanimation on smile excursion, facial symmetry, and quality of life in a cohort of children with facial palsy. STUDY DESIGN: A retrospective analysis of 40 pediatric patients who underwent FGMT for facial palsy at the Massachusetts Eye and Ear Infirmary Facial Nerve Center was performed. Preoperative and postoperative photography and videography were used to quantify smile excursion and facial symmetry. Preoperative and postoperative quality of life was assessed with the Facial Clinimetric Evaluation (FaCE) survey, a validated, patient-based instrument for evaluating facial impairment and disability. RESULTS: Of the 40 patients who underwent FGMT for facial palsy, 38 patients had complete data including preoperative and postoperative photography and videography from 3 months to 10 years following surgery; 13 cases had >5 years of follow-up. FGMT resulted in significant improvements in smile excursion within several months, with continued improvements in smile excursion and symmetry demonstrated more than 5 years later. Fifteen patients completed preoperative and postoperative FaCE surveys, which demonstrated significant improvement in quality of life scores following FGMT. CONCLUSIONS: FGMT significantly improves smile, facial asymmetry, and quality of life for years after this surgery for facial palsy.

Facial reanimation surgery in Möbius syndrome: Experience from 76 cases from a tertiary referral hospital in Latin America.

INTRODUCTION: Möbius syndrome is defined as a combined congenital bilateral facial and abducens nerve palsies. The main goal of treatment is to provide facial reanimation by means of a dynamic surgical procedure. The microneurovascular transfer of a free muscle transplant is the procedure of choice for facial animation in a child with facial paralysis. OBSERVATION: Between January 2008 and January 2017, 124 patients with the syndrome have been approached at our institution. Distribution according to Möbius Syndrome classification presents as follows: Complete Möbius syndrome (n=88), Incomplete Möbius syndrome (n=28), Möbius-Like syndrome (n=8). Seventy-nine female and 45 male patients. Sixty-one percent have undergone a microsurgical procedure (n=76), in all of them, a free gracilis flap transfer was performed. DISCUSSION: Our proposed treatment protocol for complete Möbius syndrome is determined by the available donor nerves. We prefer to use the masseteric nerve as first choice, however, if this nerve is not available, then our second choice is the spinal accesory nerve. For this purpose, all patients have an electromyography performed preoperatively. Overall, dynamic facial reanimation obtained through the microvascular transfer of the gracilis muscle have proved to improve notoriously oral comissure excursion and speech intelligibility. CONCLUSION: The free gracilis flap transfer is a reproducible procedure for patients with Möbius syndrome. It is of utmost importance to select the best motor nerve possible, based on an individualized preoperative clinical and electromyographic evaluation. To our best knowledge, this is the largest series of patients with Möbius syndrome globally, treated at a single-institution.

Outcome of a graduated minimally invasive facial reanimation in patients with facial paralysis.

Peripheral paralysis of the facial nerve is the most frequent of all cranial nerve disorders. Despite advances in facial surgery, the functional and aesthetic reconstruction of a paralyzed face remains a challenge. Graduated minimally invasive facial reanimation is based on a modular principle. According to the patients' needs, precondition, and expectations, the following modules can be performed: temporalis muscle transposition and facelift, nasal valve suspension, endoscopic brow lift, and eyelid reconstruction. Applying a concept of a graduated minimally invasive facial reanimation may help minimize surgical trauma and reduce morbidity. Twenty patients underwent a graduated minimally invasive facial reanimation. A retrospective chart review was performed with a follow-up examination between 1 and 8 months after surgery. The FACEgram software was used to calculate pre- and postoperative eyelid closure, the level of brows, nasal, and philtral symmetry as well as oral commissure position at rest and oral commissure excursion with smile. As a patient-oriented outcome parameter, the Glasgow Benefit Inventory questionnaire was applied. There was a statistically significant improvement in the postoperative score of eyelid closure, brow asymmetry, nasal asymmetry, philtral asymmetry as well as oral commissure symmetry at rest (p < 0.05). Smile evaluation revealed no significant change of oral commissure excursion. The mean Glasgow Benefit Inventory score indicated substantial improvement in patients' overall quality of life. If a primary facial nerve repair or microneurovascular tissue transfer cannot be applied, graduated minimally invasive facial reanimation is a promising option to restore facial function and symmetry at rest.

Free anterolateral thigh flap and masseter nerve transfer for reconstruction of extensive periauricular defects: Surgical technique and clinical outcomes.

BACKGROUND: Radical tumor ablation in the periauricular area often results in extensive soft tissue defects, including facial nerve sacrifice, bone and/or dura defects. Reconstruction of these defects should aim at restoring facial reanimation, wound closure, and facial and neck contours. We present our experience using free anterolateral thigh flap (ALT) in combination with masseter nerve to facial nerve transfer in managing complex defects in the periauricular area. METHODS: Between 2011 and 2015 six patients underwent a combined procedure of ALT flap reconstruction and masseter nerve transfer, to reconstruct extensive, post tumor resection, periauricular defects. The ALT flap was customized according to the defect. For smile restoration, the masseter nerve was transferred to the buccal branch of the facial nerve. If the facial nerve stump was preserved, interposition of nerve grafts to the zygomatic and frontal branches was performed to provide separate eye closure. The outcomes were analyzed by assessing wound closure, contour deformity, symmetry of the face, and facial nerve function. RESULTS: There were no partial or total flap losses. Stable wound closure and adequate volume replacement in the neck was achieved in all cases, as well as good facial tonus and symmetry. The mean follow-up time of clinical outcomes was 16.8 months. Smile restoration was graded as good or excellent in four cases, moderate in one and fair in one. CONCLUSION: Extensive periauricular defects following oncologic resection could be adequately reconstructed in a combined procedure of free ALT flap and masseter nerve transfer to the facial nerve for smile restoration.

Body proportions as possible predictors for free gracilis one-stage facial reanimation.

BACKGROUND: Gracilis muscle and its motor nerve belongs to most commonly used flap for facial reanimation. However, it is performed in two steps, which is time consuming. One stage technique can be also performed, but the length of the motor nerve cannot be currently determined before surgery. AIM: The present study was conducted in order to evaluate the body composition on the length and suitability of the motor nerve of gracilis muscle for one stage facial reanimation. METHODS: The gracilis flaps along with the motoric nerve were dissected from 20 fresh cadavers (6 females, 14 males). The length of the lower extremity from superior iliac anterior spine to the bottom of the heel and BMI were measured. Regression analysis of lower extremity length and BMI to the actual length of the motor nerve of gracilis flap was performed. RESULTS: The linear regression analysis showed a positive correlation between the length of the lower limb and the size of the motor nerve length (r = 0.5060, p < 0.05), as well as between the BMI and the size of the motor nerve length (r = 0.5073, p < 0.05). Also, the males had longer motor nerve when compared to females by 13 % (p < 0.05). No difference between females and males in BMI was observed. CONCLUSION: The length from the superior iliac anterior spine, BMI and gender seemed to be potential factors that could help to predict the length of the gracilis flap motor nerve for the one stage facial reanimation. However, further studies evaluating other anatomical factors and validating the possible prediction rule for one stage reanimation success are needed (Fig. 3, Ref. 14).

A new paradigm in facial reanimation for long-standing palsies?

BACKGROUND: A chance observation of return of excellent facial movement, after 18 months following the first stage of cross-face nerve grafting, without free functional muscle transfer, in a case of long-standing facial palsy, lead the senior author (RBA) to further investigate clinically. PATIENTS AND METHODS: This procedure, now christened as cross-face nerve extension and neurotization, was carried out in 12 patients of very long-standing facial palsy (mean 21 years) in years 1996-2011. The mean patient age and duration of palsy were 30.58 years and 21.08 years, respectively. In patients, 1-5 a single buccal or zygomatic branch served as a donor nerve, but subsequently, we used two donor nerves. The mean follow-up period was 20.75 months. RESULTS: Successive patients had excellent to good return of facial expression with two fair results. Besides improved smile, patients could largely retain air in the mouth without any escape and had improved mastication. No complications were encountered except synkinesis in 1 patient. No additional surgical procedures were performed. CONCLUSION: There is experimental evidence to suggest that neurotization of a completely denervated muscle can occur by the formation of new ectopic motor end plates. Long-standing denervated muscle fibres eventually atrophy severely but are capable of re-innervation and regeneration, as validated by electron microscopic studies. In spite of several suggestions in the literature to clinically validate functional recovery by direct neurotization, the concept remains anecdotal. Our results substantiate this procedure, and it has the potential to simplify reanimation in longstanding facial palsy. Our work now needs validation by other investigators in the field of restoring facial animation.

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.

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.

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.

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.