Qualitative and Quantitative Analysis of Smile Excursion in Facial Reanimation: A Systematic Review and Meta-analysis of 1- versus 2-stage Procedures

Evaluation of the Patient with Facial Palsy: A Multidisciplinary Approach

This article aims to provide an overview of the management of facial palsy within a multidisciplinary team setting and discusses considerations used to develop patient-specific management plans. The national landscape of facial function services is also discussed including suggestions on what may enable a more equitable and sustainable service for the future.

Novel Method of Dual-innervated Free Gracilis Muscle Transfer for Facial Reanimation: A Case Series

Background

Dynamic facial reanimation is the gold standard treatment for a paralyzed face. The use of the cross-face nerve graft (CFNG) in combination with the masseteric nerve to innervate the free gracilis muscle has been reported to provide both spontaneity and strong neural input. We report a case series of dual innervation, using a novel method where the branch to masseter is coapted to the side of the CFNG.

Methods

Eight patients received free gracilis muscle transfer using the new dual innervation method between September 2014 and December 2017. The CFNG, which was performed nine months prior, was sutured in an end-to-end fashion to the obturator nerve. A nerve graft was coapted to the ipsilateral masseteric nerve and then sutured in an end-to-side fashion to the CFNG proximal to its coaptation to the obturator nerve.

Results

All patients recovered smile function with and without teeth clenching around the same time period. Smiles without teeth clenching appeared later in two of eight patients and earlier in one of eight patients, being noted at an average of 8.25 months of follow-up versus 7.6 months. The estimate of true attainment is limited by the spacing of follow-up dates. Average follow-up time was 36.07 months (range: 10-71.5). FACE-Gram software smile analysis with and without biting demonstrated similar excursion on average (7.64 mm versus 8.6 mm respectively, P = 0.93), both of which are significantly improved from preoperation.

Conclusion

This novel method of a dual-innervated free gracilis muscle transfer offers a viable technique that achieves a symmetric, strong, and emotional smile.

The Emerging Role of Artificial Intelligence Tools for Outcome Measurement in Facial Reanimation Surgery: A Review

Importance: Surgeons treating facial paralysis with reanimation surgery measure the outcomes of surgery and adjust treatment to each patient's needs. Our objective is to review the current subjective facial paralysis assessment tools and the emerging computer-based objective analysis, which may involve artificial intelligence. Observations: In recent years, many new automated approaches to outcome measurement in facial reanimation surgery have been developed. Most of these tools utilize artificial intelligence to analyze emotional expression and symmetry of facial landmarks. Other tools have provided automated approaches to existing clinician-guided scales. Conclusions: Newly developed computer-based tools using artificial intelligence have been developed to both improve existing clinician-graded scales and provide new approaches to facial symmetry and emotional expressivity analysis.

Donor nerve selection in free gracilis muscle transfer for facial reanimation. A systematic review and meta-analysis of clinical outcomes

BACKGROUND

One of the critical factors in facial reanimation is selecting the donor nerve. The most favored neurotizers are the contralateral facial nerve with a cross-face nerve graft (CFNG) and motor nerve to the masseter (MNM). A relatively new dual innervation (DI) method has shown successful results. This study aimed to compare the clinical outcomes of different neurotization strategies for free gracilis muscle transfer (FGMT).

METHODS

The Scopus and WoS databases were queried with 21 keywords. Three-stage article selection was performed for the systematic review. Articles presenting quantitative data for commissure excursion and facial symmetry were included in meta-analysis, using random-effects model. ROBINS-I tool and Newcastle-Ottawa scale were used to assess bias and study quality.

RESULTS

One hundred forty-seven articles containing FGMT were systematically reviewed. Most studies indicated CFNG as the first choice. MNM was primarily indicated in bilateral palsy and in elderly. Clinical outcomes of DI studies were promising. 13 studies including 435 observations (179 CFNG, 182 MNM, 74 DI) were eligible for meta-analysis. The mean change in commissure excursion was 7.15 mm (95% CI: 4.57-9.72) for CFNG, 8.46 mm (95% CI: 6.86-10.06) for MNM, and 5.18 mm (95% CI: 4.01-6.34) for DI. In pairwise comparisons, a significant difference was found between MNM and DI (p = 0.0011), despite the superior outcomes described in DI studies. No statistically significant difference was found in resting and smile symmetry (p = 0.625, p = 0.780).

CONCLUSIONS

CFNG is the most preferred neurotizer, and MNM is a reliable second option. Outcomes of DI studies are promising, but more comparison studies are needed to draw conclusions. Our meta-analysis was limited by incompatibility of the assessment scales. Consensus on a standardized assessment system would add value to future studies.

A Ready-to-Use Grading Tool for Facial Palsy Examiners-Automated Grading System in Facial Palsy Patients Made Easy

BACKGROUND

The grading process in facial palsy (FP) patients is crucial for time- and cost-effective therapy decision-making. The House-Brackmann scale (HBS) represents the most commonly used classification system in FP diagnostics. This study investigated the benefits of linking machine learning (ML) techniques with the HBS.

METHODS

Image datasets of 51 patients seen at the Department of Plastic, Hand, and Reconstructive Surgery at the University Hospital Regensburg, Germany, between June 2020 and May 2021, were used to build the neural network. A total of nine facial poses per patient were used to automatically determine the HBS.

RESULTS

The algorithm had an accuracy of 98%. The algorithm processed the real patient image series (i.e., nine images per patient) in 112 ms. For optimized accuracy, we found 30 training runs to be the most effective training length.

CONCLUSION

We have developed an easy-to-use, time- and cost-efficient algorithm that provides highly accurate automated grading of FP patient images. In combination with our application, the algorithm may facilitate the FP surgeon's clinical workflow.

The sternohyoid muscle flap for new dynamic facial reanimation technique: Anatomical study and clinical results

BACKGROUND

Long-term facial nerve palsy has a highly negative impact on patients' quality of life. In 2016, Alam reported one case of facial reanimation with the sternohyoid muscle after publishing a preclinical study in 2013. Despite the potentially ideal characteristics of this muscle for reanimation of facial palsy, this technique is still not widely used. The objective of our description of cases was to present the clinical results obtained with the surgical procedure and the study on cadavers to confirm the anatomical findings.

METHODS

This work describes the anatomical study of the vascular and nervous pedicle of the sternohyoid muscle compared with clinical results from a series of patients with long-term facial paralysis who underwent facial reanimation between June 2016 and September 2019, through the insertion of the sternohyoid muscle into the masseteric nerve.

RESULTS

The anatomical study was conducted in eight human hemi-necks. In five cases (62%), the vascular pedicle was provided by the superior thyroid artery, and the entrance of the ansa cervicalis to the muscle was constant 1.8 cm from the distal insertion. This series included ten patients who underwent the surgery technique of facial reanimation using the sternohyoid muscle, with a 90% (n = 9) of reinnervation; 100% (n = 10) of flaps were viable, and none of the patients showed complications in the donor area.

CONCLUSIONS

The sternohyoid muscle showed itself as a reliable muscle as a free flap in facial reanimation, and alternative to the gracilis flap. The surgical technique was safe, without any complications, with excellent excursion, recovery, and aesthetic results.

Acute Peripheral Facial Palsy: Recent Guidelines and a Systematic Review of the Literature

BACKGROUND

This study reviews recent literature on facial palsy guidelines and provides systematic reviews on related topics of interest.

METHODS

An electronic database search was performed to identify recent guidelines dealing with facial nerve palsy, systematic reviews and recent meta-analysis published between 2011 and 2019 (inclusive). The literature search used the search terms "Bell's palsy," "Ramsay-Hunt syndrome," "Facial palsy," "Facial paralysis," "Facial paresis," "Guideline," "Meta-analysis," "Systematic review," and "Randomized controlled trial." Only studies written in English were used.

RESULTS

The characteristics of treatment trends for facial palsy have been reviewed over the past decade. The most prominent change noted may be the shift from the conventional House-Brackmann facial nerve grading system to the Sunnybrook and eFACE systems. In addition, the results of serial meta-analyses indicate increasing agreement with the use of surgical decompression of the facial nerve. Beyond steroids or combined steroid-antiviral treatment, various novel drugs and treatments have been tried. For long-standing facial paralysis and postparetic synkinesis sequelae after facial palsy, facial reanimation has been highlighted and the necessity of new paradigms have been raised.

CONCLUSION

For peripheral facial paralysis, various changes have been made, not only in the facial nerve grading systems, but also in medical treatments, from surgical procedures to rehabilitation, during the last decade.

Impact of increasing age on functioning free muscle transplantation for facial palsy reconstruction

BACKGROUND

Management of facial paralysis in older patients is controversial. The purpose of this study is to evaluate the impact of increasing age on functioning free muscle transplantation (FFMT).

PATIENTS AND METHODS

Twenty-nine facial paralysis patients over 50 years old received FFMT. A separate group of patients aged 41-50 years old were included as control. Outcome assessments included use of the SMILE evaluation system for excursion, a cortical adaptation scoring system for brain plasticity, and a subjective satisfaction assessment score. Meta-analysis of literature over the past 50 years was also performed to examine the impact of older age.

RESULTS

The mean change in excursion movement was 13.39 ± 5.49 mm. Weakest excursion was found in the oldest age group (11.74 ± 4.84 mm, p = .097), in concordance with the meta-analysis. There was significant difference between the three different neurotizers (p = .036). Excursion and satisfaction score were significantly worse in the older cohort with the cross face-nerve graft FFMT.

CONCLUSIONS

FFMT is a viable option in the elderly patient group but performs weaker in excursion. The choice of neurotizer is dependent on the patient's goals and the suitable age at which the benefits outweigh the risks.

Reuse of the Masseteric Nerve for Dynamic Reanimation in Facial Palsy Patients with Previously Failed One-Stage Dynamic Smile Reanimation

Failed primary dynamic smile reanimation procedures present significant challenges for the patient and surgeon alike. This is particularly true in older patients with a history of previous neck dissection and radiation therapy who underwent previous reconstruction with a free functional muscle transfer innervated with an ipsilateral masseter nerve. The objective of this study was to demonstrate feasibility, describe surgical technique, and assess results of reusing the masseter nerve to reinnervate a new free functional muscle transfer. Patients presenting between 2007 and 2017 to a single center after previously failed dynamic smile reanimation using the masseteric nerve who underwent a salvage dynamic procedure involving reuse of the masseteric nerve were analyzed for demographics, history of radiation therapy or chemotherapy, surgical techniques, and objective measurements using the MEEI Facegram software. The average age was 50 years, the average duration of palsy was 6.2 years, and the average preoperative House-Brackmann score was 6. Causes of palsy included Bell palsy in one, parotid malignancies in two, and a seventh cranial nerve schwannoma in one patient, with two patients requiring radiation therapy preoperatively. Three patients failed to achieve any motion after the first reanimation, and the fourth patient initially achieved excursion; however, because of cancer recurrence and resection of free functional muscle transfer, motion was subsequently lost. Average smile excursion after salvage was 11.32 mm and philtral deviation correction was 1.3 mm. Reusing the masseter nerve for dynamic smile restoration with free functional muscle transfer in previously failed reanimation patients is feasible and may provide successful reanimation. Careful patient evaluation and clear understanding of previous procedures are essential for success. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

A Rapid Protocol for Intraoperative Assessment of Peripheral Nerve Myelinated Axon Count and Its Application to Cross-Facial Nerve Grafting

BACKGROUND

Donor nerve myelinated axon counts correlate with functional outcomes in reanimation procedures; however, there exists no reliable means for their intraoperative quantification. In this article, the authors report a novel protocol for rapid quantification of myelinated axons from frozen sections, and demonstrate its applicability to surgical practice.

METHODS

The impact of various fixation and FluoroMyelin Red staining strategies on resolved myelin sheath morphology from cryosections of rat and rabbit femoral and sciatic nerves was assessed. A protocol comprising fresh cryosection and rapid staining was developed, and histomorphometric results were compared against conventional osmium-postfixed, resin-embedded, toluidine blue-stained sections of rat sciatic nerve. The rapid protocol was applied for intraoperative quantification of donor nerve myelinated axon count in a cross-facial nerve grafting procedure.

RESULTS

Resolution of myelinated axon morphology suitable for counting was realized within 10 minutes of tissue harvest. Although mean myelinated axon diameter appeared larger using the rapid fresh-frozen as compared to conventional nerve processing techniques (mean ± SD; rapid, 9.25 ± 0.62 μm; conventional, 6.05 ± 0.71 μm; p < 0.001), no difference in axon counts was observed on high-power fields (rapid, 429.42 ± 49.32; conventional, 460.32 ± 69.96; p = 0.277). Whole nerve myelinated axon counts using the rapid protocol herein (8435.12 ± 1329.72) were similar to prior reports using conventional osmium processing of rat sciatic nerve.

CONCLUSIONS

A rapid protocol for quantification of myelinated axon counts from peripheral nerves using widely available equipment and techniques has been described, rendering possible intraoperative assessment of donor nerve suitability for reanimation.