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

Outcomes of Free Flap Transfer in Facial Reanimation: A Review

Free functional muscle transfer is is an option for reanimating the face in chronic facial nerve paralysis. The optimal outcome in these patients is the ability to restore a spontaneous smile in response to emotion. We discuss the role of free functional muscle transfer in facial paralysis treatment, the choices of nerve used in reconstruction surgery, and the application of different types of muscle flaps in facial reanimation. In this paper, we review the relevant and up-to-date academic literature regarding the outcomes of free functional muscle flap transfer in facial paralysis patients.

Task force of the Brazilian Society of Otology - evaluation and management of peripheral facial palsy

OBJECTIVE

To review key evidence-based recommendations for the diagnosis and treatment of peripheral facial palsy in children and adults.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on peripheral facial palsy were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 main parts: (1) Evaluation and diagnosis of facial palsy: electrophysiologic tests, idiopathic facial palsy, Ramsay Hunt syndrome, traumatic peripheral facial palsy, recurrent peripheral facial palsy, facial nerve tumors, and peripheral facial palsy in children; and (2) Rehabilitation procedures: surgical decompression of the facial nerve, facial nerve grafting, surgical treatment of long-term peripheral facial palsy, and non-surgical rehabilitation of the facial nerve.

CONCLUSIONS

Peripheral facial palsy is a condition of diverse etiology. Treatment should be individualized according to the cause of facial nerve dysfunction, but the literature presents better evidence-based recommendations for systemic corticosteroid therapy.

Neurofibromatosis Type II and Facial Paralysis: Clinical Evaluation and Management

BACKGROUND

Facial paralysis secondary to neurofibromatosis type 2 (NF2) presents the reconstructive surgeon with unique challenges because of its pathognomonic feature of bilateral acoustic neuromas, involvement of multiple cranial nerves, use of antineoplastic agents, and management. Facial reanimation literature on managing this patient population is scant.

METHODS

A comprehensive literature review was performed. All patients with NF2-related facial paralysis who presented in the past 13 years were reviewed retrospectively for type and degree of paralysis, NF2 sequelae, number of cranial nerves involved, interventional modalities, and surgical notes.

RESULTS

Twelve patients with NF2-related facial paralysis were identified. All patients presented after resection of vestibular schwannoma. Mean duration of weakness before surgical intervention was 8 months. On presentation, one patient had bilateral facial weakness, 11 had multiple cranial nerve involvement, and seven were treated with antineoplastic agents. Two patients underwent gracilis free functional muscle transfer, five underwent masseteric-to-facial nerve transfer (of whom two were dually innervated with a crossfacial nerve graft), and one patient underwent depressor anguli oris myectomy. Trigeminal schwannomas did not affect reconstructive outcomes if trigeminal nerve motor function on clinical examination was normal. In addition, antineoplastic agents such as bevacizumab and temsirolimus did not affect outcomes if stopped in the perioperative period.

CONCLUSIONS

Effectively managing patients with NF2-related facial paralysis necessitates understanding the progressive and systemic nature of the disease, bilateral facial nerve and multiple cranial nerve involvement, and common antineoplastic treatments. Neither antineoplastic agents nor trigeminal nerve schwannomas associated with normal examination affected outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

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.

Comparison of Outcomes of Smile Reanimation Between Dual- Versus Single-Innervation Technique in Single-Stage Latissimus Dorsi Neuromuscular Transfer in Facial Paralysis Patients

Background: Although a dual-innervation technique has emerged in single-stage functional latissimus dorsi (LD) muscle transfer for smile reanimation, its benefits over conventional techniques have not been elucidated. Objective: To compare outcomes of dual-innervation technique with those of single-innervation. Methods: Patients with facial palsy treated with single-stage functional LD muscle transfer were identified, and categorized into two groups: single and dual innervation. Outcomes were assessed using clinical examination based on the Terzis grading system and using automated software (Emotrics). Results: Fifty-nine patients (mean age 37.6 years; male/female 30/29) were analyzed, including 40 in single (35.1 years, 23/17) and 19 in dual-innervation group (43.0 years, 7/12), with a median follow-up of 34 months (range, 9-165) (single: 41.5, 12-165, dual: 23.0, 9-41). Tumor-related paralysis was the most common etiology in both groups (overall: 45.8%, single: 40.0%, dual: 57.9%). The dual group had a significantly higher rate of cases with Terzis grade IV or V postoperatively. In the Emotrics-based evaluation, the dual group exhibited significantly enhanced improvements in smile excursion in the dynamic state compared with the single. The degree of improvement in the resting state did not differ between groups. Conclusion: The dual-innervation technique might provide promising results in achieving enhanced smile excursion.

Muscle transposition and free muscle transfer in facial nerve reanimation

PURPOSE OF REVIEW

This review highlights recent advances in facial reanimation surgery particularly related to muscle transposition and free functional muscle transfer (FFMT).

RECENT FINDINGS

FFMT and muscle transposition are mainstays in the treatment of chronic facial paralysis. Recent literature evaluates single versus dual innervated FFMT, reanimation of the periocular region and lower lip depressors, and indications for such methods over gold standard FFMT techniques. New donor sites for muscle transposition and FFMT are also described.

SUMMARY

Gracilis FFMT (GFMT) continues to be the gold standard in dynamic facial reanimation for patients with chronic facial paralysis. Muscle transposition should be considered in older patients, those medically unfit for long operative procedures, and individuals who prefer more immediate results. With respect to FFMT, described nerve coaptation patterns, surgical stages, and donor muscle choice vary. Standardization of data reporting and outcome measures is needed in future studies.

Embellishing Emotrics for a More Complete Emotion Analysis: Addition of the Nasolabial Fold

Background: The nasolabial fold (NLF) greatly contributes to facial aesthetics; changes to NLF depth and vector are disfiguring in patients with facial paralysis (FP). NLF parameters are integral to clinician-graded outcomes, but automated programs currently lack NLF identification capabilities. Objective: To incorporate an automated NLF identification and quantification function into the facial landmark program, Emotrics, and to compare new Emotrics-derived NLF data to clinician-graded electronic facial paralysis assessment (eFACE) data for accuracy. Methods: Photographs of 135 patients with FP were marked bilaterally, using identification markers manually placed on each NLF. A machine learning model was trained to automatically localize the markers using these data. Once Emotrics accurately identified the NLF and its corresponding vector, photographs of 20 additional patients who underwent facial reanimation procedures were assessed by the algorithm. Results: The enhanced Emotrics algorithm successfully identified the NLF, and measured the vector from midline, in a series of patients with FP. NLF vector data closely matched corresponding eFACE parameters. Furthermore, changes in NLF presence and vector were detected following facial reanimation procedures. Conclusion: The Emotrics program now provides critical NLF data, providing objective parameters for clinicians interested in changing NLF dynamics after FP.

Gracilis Muscle-Free Flap Objective Improvement of Oral Commissure Excursion in Facial Palsy Reanimation Surgery: Systematic Review and Meta-Analysis

Background: Facial palsy patients face significant challenges. Gracilis free flap transfer is a key procedure in facial reanimation. Objective: This study aims to analyze oral commissure excursion improvement after gracilis free flap transfer and the differences regarding donor nerve: cross-facial nerve graft (CFNG), hypoglossal or spinal accessory nerves, motor nerve to masseteric (MNTM), and most recently, double anastomosis using both the MNTM and CFNG. Methods: A systematic review and meta-analysis were conducted of studies reporting oral commissure excursion improvement after free gracilis muscle transfer. Pooled proportions were calculated using a random-effects model. Results: Eighteen studies, 453 patients, and 488 free gracilis flaps were included. The mean change in perioperative oral commissure excursion was 7.0 mm, for CFNG 7.2 mm, for MNTM 7.7, and for double anastomoses 5.5 mm. Conclusions: There is a significant improvement in oral commissure excursion after gracilis muscle-free flap. Unfortunately, we could not make definitive conclusions regarding the optimal choice of donor nerve.

Quantitative analysis of facial symmetry and animation following intraoral orthodromic temporalis transfer in facial paralysis

This study aimed to quantitatively analyze the degree and vector of commissure excursion following intraoral orthodromic temporalis transfer. Patients with unilateral facial paralysis who underwent intraoral temporalis transfer were included. Intra-oral coronoidectomy was followed by submucosa tunneling through two vertical intraoral incisions to fixate the temporalis tendon to the perioral location. Oral commissure excursion, upper lip and commissure height differences, and smile angle were measured. Postoperatively, the symmetry of commissure excursion improved in repose (affected side: 114.6 ± 7.0 mm, non-affected side: 115.2 ± 4.9 mm, p = 0.134), while asymmetry arose in smiling (affected side: 30.7 ± 3.4 mm, non-affected side: 34.5 ± 4.4 mm, p = 0.001). Furthermore, the postoperative smile angle demonstrated insufficient vertical movement on the affected side during smiling (affected side: 115.6 ± 5.8°, non-affected side: 118.4 ± 4.9°, p = 0.002) but no significant difference in repose (p = 0.134). Within the limitations of the study it seems that intraoral orthodromic temporalis transfer yields excellent resting symmetry, but smile asymmetry may occur owing to insufficient oral commissure excursion. Nevertheless, as a minimally invasive surgery, this technique can obviate visible scars and benefit patients wishing for the same and can have excellent resting symmetry.

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.