The "babysitter" procedure: minihypoglossal to facial nerve transfer and cross-facial nerve grafting

Current Treatments and Future Directions for Facial Paralysis

Facial palsy is a condition that affects the facial nerve, the seventh of the 12 cranial nerves. Its main function is to control the muscles of facial expression. This involves the ability to express emotion through controlling the position of the mouth, the eyebrow, nostrils, and eye closure. The facial nerve also plays a key role in maintaining the posture of the mouth and as such, people with facial paralysis often have problems with drooling, speech, and dental hygiene.Due to the devastating effects on the quality of life of individuals with facial palsy, there are a multitude of various treatment options for the paralyzed face. This article reviews current management strategies and points towards promising future directions for research in the field of facial reanimation.

Nerve Autograft: Preservation of a Lost Art

Nerve autografts involve the transplantation of a segment of the patient's own nerve to bridge a nerve gap. Autografts provide biological compatibility, support for axonal regeneration, and the ability to provide an anatomic scaffold for regrowth that other modalities may not match. Disadvantages of the autograft include donor site morbidity and the extra operative time needed to harvest the graft. Nevertheless, nerve autografts such as the sural nerve remain the gold standard in reconstructing nerve gaps, but a multitude of factors need to be favorable in order to garner reliable, consistent outcomes.

Alternative Nerve Coaptations: End-To-Side and Beyond

Modern end-to-side (ETS) nerve transfers have undergone several permutations since the early 1990's. Preclinical data have revealed important mechanisms and patterns of donor axon outgrowth into the recipient nerves and target reinnervation. The versatility of ETS nerve transfers can also potentially address several processes that limit functional recovery after nerve injury by babysitting motor end-plates and/or supporting the regenerative environment within the denervated nerve. Further clinical and basic science work is required to clarify the ideal clinical indications, contraindications, and mechanisms of action for these techniques in order to maximize their potential as reconstructive options.

"Deep masseteric triangular area to define masseter neurovascular bundle: A cadaveric study"

INTRODUCTION

Facial reanimation procedures are used in the treatment of the disorder that impairs mimetic function and jeopardizes physical and psychological health, and one of the most important instruments of these techniques is the masseteric neurovascular bundle (NVB) and proper identification at the mandibular notch level. In the current study, a triangular area (deep masseteric triangle, DMT) on the lateral surface of the masseter muscle that was identified to help reliable determination of the masseteric NVB at the mandibular notch level.

MATERIAL AND METHODS

40 parotideomasseteric region dissections were performed in 10 female and 10 male donated cadavers. Structures lateral to the masseter muscle were removed. The edge length of the masseter muscle on the zygomatic arch side was measured. After the edges of the DMT were measured, the masseteric NVB was found by dissection and its distance (depth) from the skin line was measured.

RESULTS

The mean lengths of the superior, posterior, and anterior margins were 17.3 (±4.5) mm, 25.9 (±6.2) mm, and 26.3 (±6.5) mm, respectively. The total length of the upper edge of the masseteric muscle attached to the zygomatic arch averaged 52.7 (±5.2) mm. The masseteric neurovascular bundle was detected at a depth of approximately 17 mm from the skin of the parotideamasseteric region.

DISCUSSION

The visualization of the DMT can be used as an important landmark for access to branch-free part of the masseteric nerve. Moreover, an specific approach for masseteric NVB localization can be established by drawing a line between the mandibular angle and the midpoint of the upper edge of the DMT. This technique can greatly improve the accuracy of both masseteric nerve harvesting and masseteric nerve block procedures.

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.

Novel Technologies to Address the Lower Motor Neuron Injury and Augment Reconstruction in Spinal Cord Injury

Lower motor neuron (LMN) damage results in denervation of the associated muscle targets and is a significant yet under-appreciated component of spinal cord injury (SCI). Denervated muscle undergoes a progressive degeneration and fibro-fatty infiltration that eventually renders the muscle non-viable unless reinnervated within a limited time window. The distal nerve deprived of axons also undergoes degeneration and fibrosis making it less receptive to axons. In this review, we describe the LMN injury associated with SCI and its clinical consequences. The process of degeneration of the muscle and nerve is broken down into the primary components of the neuromuscular circuit and reviewed, including the nerve and Schwann cells, the neuromuscular junction, and the muscle. Finally, we discuss three promising strategies to reverse denervation atrophy. These include providing surrogate axons from local sources; introducing stem cell-derived spinal motor neurons into the nerve to provide the missing axons; and finally, instituting a training program of high-energy electrical stimulation to directly rehabilitate these muscles. Successful interventions for denervation atrophy would significantly expand reconstructive options for cervical SCI and could be transformative for the predominantly LMN injuries of the conus medullaris and cauda equina.

Cross-Facial Nerve Grafting Used Independently in Facial Reanimation: A Narrative Review

Importance: Cross-Facial Nerve Grafting (CFNG) for facial palsy offers potential to restore spontaneous facial expression, but specific indications and associated outcomes are limited. Updates to this technique have aided in its successful employment in select cases. This review aims to explore the context in which CFNG has been successfully utilized as a primary modality. Observations: Literature review was performed auditing all studies investigating CFNG as a primary modality, which reported outcomes. A total of 326 cases reporting outcomes for primary CFNG were included. Eye closure outcomes were 83.3% successful at ages 0-18, 77.3% successful at ages 19-40, and 57.1% successful at ages 41+. Smile outcomes were 73.7% successful at ages 0-18, 81.5% successful at ages 19-40, and 52.8% successful at ages 41+. For synkinesis, 89% of cases were considered successful; 100% successful at ages 0-18, and 78.4% successful in adults. Conclusions and Relevance: CFNG may offer return of spontaneous facial function in select cases. Higher percentages of successful outcomes are observed in younger patients, when performed in two stages, and when performed earlier from the onset of FP in cases of eye closure restoration. In the modern era, CFNG has been more commonly employed as an adjunctive procedure to other reanimation techniques.

Functional Outcome of Dual Reinnervation with Cross-Facial Nerve Graft and Masseteric Nerve Transfer for Facial Paralysis

BACKGROUND

The combination of cross-facial nerve graft (CFNG) and masseteric nerve transfer (MNT) for reinnervation of facial paralysis may provide advantages of both neural sources. However, quantitative functional outcome reports with a larger number of patients are lacking in the literature. Here, the authors describe their 8-year experience with this surgical technique.

METHODS

Twenty patients who presented with complete facial paralysis (duration, <12 months) received dual reinnervation with CFNG and MNT. The functional outcome of the procedure was evaluated with the physician-graded outcome metric eFACE scale. The objective artificial intelligence-driven software Emotrics and FaceReader were used for oral commissure measurements and emotional expression assessment, respectively.

RESULTS

The mean follow-up was 31.75 ± 23.32 months. In the eFACE score, the nasolabial fold depth and oral commissure at rest improved significantly ( P < 0.05) toward a more balanced state after surgery. Postoperatively, there was a significant decrease in oral commissure asymmetry while smiling (from 19.22 ± 6.1 mm to 12.19 ± 7.52 mm). For emotional expression, the median intensity score of happiness, as measured by the FaceReader software, increased significantly while smiling (0.28; interquartile range, 0.13 to 0.64). In five patients (25%), a secondary static midface suspension with fascia lata strip had to be performed because of unsatisfactory resting symmetry. Older patients and patients with greater preoperative resting asymmetry were more likely to receive static midface suspension.

CONCLUSION

The authors' results suggest that the combination of MNT and CFNG for reinnervation of facial paralysis provides good voluntary motion and may lessen the use of static midface suspension in the majority of patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The effect of various muscle transfer procedures on eye closure and blinking in longstanding facial palsy patients

BACKGROUND

Facial palsy causes paralytic lagophthalmos, which remarkably deteriorates a patient's quality of life. In cases where denervation time is over 18-24 months (longstanding facial palsy), a free or pedicled muscle transfer is needed to replace the denervated orbicularis oculi muscle.

PURPOSE

The purpose of this systematic review is to investigate the effect of various eye sphincter substitution procedures (free or pedicled muscle transfers) in longstanding facial palsy patients on eye closure and blink.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we performed a systematic review of the Embase, Medline, Web of Science and Cochrane Library databases and Google Scholar. Our literature search yielded 4322 articles. Following a full-text review, 4 retrospective cohort studies and 21 case series were selected for this review. Meta-analyses using R package meta (version 6.5-0) were conducted.

MAIN FINDINGS

All free and pedicled muscle transfers in this review showed an improvement in the scores and measurements on eye closure and blink. The pedicled temporalis muscle transfer was the procedure most commonly performed as eye reanimation surgery and showed consistent good results. Using the random effects model, the pooled effect of mean difference in lagophthalmos after gentle eye closure post-operatively versus pre-operatively (mm) in patients who received a pedicled (temporalis) muscle transfer was -6.19 (I2 = 85%, 95% CI: -7.89; -4.49) whereas it was -4.11 (I2 = 85%, 95% CI: -7.26; -0.95) for free (gracilis or platysma) muscle transfers. The pooled proportion of patients with complete eye closure after surgery was 0.69 (I2 = 49%, 95% CI: 0.54; 0.82) in patients who received a pedicled (temporalis) muscle transfer and 0.40 (I2 = 74%, 95% CI: 0.13; 0.74) in patients who received a free (platysma) muscle transfer.

CONCLUSIONS

Unlike smile reanimation, dynamic eye closure and blink restoration are rather neglected topics in facial reanimation. The pedicled temporalis muscle transfer is often recommended as the first treatment of choice for eye reanimation in longstanding facial palsy patients since it is a reliable, straightforward procedure, that does not require complex microsurgery. However, with the advancements in the field of microsurgery, free muscle transfers are promising therapies, which may regenerate voluntary and spontaneous blinking.

Does supercharging with cross-face nerve graft enhance smile in non-flaccid facial paralysis patients undergoing selective neurectomy?

BACKGROUND

Cross face nerve grafting (CFNG) is a well-established nerve transfer technique in facial reanimation; however, no study has assessed outcome of supercharging the smile with CFNG in patients with synkinesis. The goal of this study was to examine the smile outcome in non-flaccid facial paralysis (NFFP) patients after supercharging with CFNG during selective neurectomy.

METHODS

NFFP patients who underwent CFNG with end-to-side coaptation to a smile branch on the paralyzed side during selective neurectomy were retrospectively identified and their charts were reviewed. Pre-operative and post-operative facial function was assessed with the electronic clinician-graded facial function tool (eFACE), and an automated computer-aided facial assessment tool (Emotrics). Smile metrics were compared pre-operatively, in early post-operative time (EPO, <6 months), and late post-operative time (LPO, >9 months) when CFNG contribution would be expected.

RESULTS

Thirteen cases were performed between June 2019 and December 2021. No objective smile metrics improved following supercharging with CFNG. Oral commissure excursion improved by 1.23 points in eFACE (p = .812), and by 0.84 in Emotrtics (p = .187) from EPO to LPO. EFACE dynamic score was improved by 0.08 points from EPO to LPO (p = .969).

CONCLUSIONS

Using CFNG for supercharging the smile during selective neurectomy in NFFP patients may not enhance smile. Longer term results following supercharging and long term natural history of selective neurectomy should be assessed.

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

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

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.

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.

Triple nerve transfers for the management of early unilateral facial palsy

BACKGROUND

Early onset facial paralysis is usually managed with cross-face nerve grafts, however the low number of axons that reach the target muscle may result in weakness or failure. Multiple-source innervation, or 'supercharging', seeks to combine the advantages of different donor nerves while minimizing their weaknesses. We propose a combination of cross-face nerve grafts with local extra-facial nerve transfers to achieve earlier facial reanimation in our patients.

METHODS

A retrospective cohort including all patients with early unilateral facial palsy (<12 months evolution) who underwent triple nerve transfer between 2019 and 2021 was conducted. We performed single-stage procedure including zygomatic-to-zygomatic and buccal-to-buccal cross-face grafts, a nerve-to-masseter to bucozygomatic trunk transfer, and a mini-hypoglossal to marginal branch transfer. Results were evaluated using the clinician-graded facial function scale (eFACE).

RESULTS

Fifteen patients were included (eight females, seven males), mean age at the time of surgery was 48.9 ± 13.3 years. Palsy was right-sided in eight cases. The mean time from palsy onset to surgery was 5.5 ± 2.8 months. Patients showed improvement in static (70.8 ± 21.9 vs. 84.15 ± 6.68, p = 0.002) and dynamic scores (20 ± 16.32 vs. 74.23 ± 7.46, p < 0.001), as well as periocular (57.33 ± 15.23 vs. 74 ± 7.18, p = 0.007), smile (54.73 ± 11.93 vs. 85.62 ± 3.86, p < 0.001), mid-face (46.33 ± 18.04 vs. 95 ± 7.21, p < 0.001) and lower face scores (67.4 ± 1.55 vs. 90.31 ± 7.54, p < 0.001).

CONCLUSION

The triple nerve transfer technique using cross-face nerve grafts, the nerve-to-masseter, and the hypoglossal nerve, is an effective and reproducible technique to obtain middle and lower face reanimation in cases of early facial palsy.

Periocular management in recent facial palsy patients treated with triple innervation technique: A retrospective case series

Facial paralysis decreases eye protection mechanisms leading to ocular problems up to corneal ulceration, and blindness. This study aimed to evaluate the outcomes of periocular procedures for recent facial paralysis. Medical records of patients with unilateral recent complete facial palsy who did periocular procedures at the Maxillofacial Surgery Department of San Paolo Hospital (Milan, Italy) between April 2018 and November 2021 were retrospectively reviewed. 26 patients were included. All patients were evaluated 4 months after surgery. The first group included 9 patients who underwent upper eye lid lipofilling and midface suspension with fascia lata graft; they had no ocular dryness symptoms and no need for eye protection measures in 33.3% of cases, significant reduction of ocular symptoms and need for eye protection measures in 66.6% of patient, 0-2 mm lagophthalmos in 66.6% and 3-4 mm lagophthalmos in 33.3%. The second group of 17 patients who underwent upper eyelid lipofilling, midface suspension with fascia lata graft and lateral tarsorrhaphy, had no ocular dryness symptoms and no need for eye protection measures in 17.6% of patient, significant reduction of ocular symptoms and need for eye protection measures in 76.4% of patient, 0-2 mm lagophthalmos in 70.5%, 3-4 mm lagophthalmos in 23.5% and one patient 5,8%had 8 mm lagophthalmos and persistent symptoms. No ocular complication, cosmetic complain or donner site morbidity were reported. Upper eyelid lipofilling, midface suspension with fascia lata graft and lateral tarsorrhaphy decrease ocular dryness symptoms and need for eye protection measures and improve lagophthalmos: the association of the reinnervation with these complementary techniques is therefore highly recommended in order to immediately protect the eye.

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.

The Role of the Cross Face Nerve Graft in Facial Reanimation and Endoscopic Harvest of the Sural Nerve

Cross-face nerve grafting (CFNG) allows for spontaneous, involuntary facial movement for patients with irreversible hemifacial paralysis. This technique uses an intact contralateral facial nucleus and nerve as an input and axon source, allowing donor neural input to be routed through a nerve graft across the face. The sural nerve is well equipped for use as a nerve graft due to its length and minimal donor site morbidity. Endoscopic nerve harvest techniques allow for efficient, minimally invasive dissection that improves the integrity of the harvested nerve.

Surgical Anatomy of Temporalis Muscle Transfer with Fascia Lata Augmentation for the Reanimation of the Paralyzed Face: A Cadaveric Study

Background  The temporalis muscle flap transfer with fascia lata augmentation (FLA) is a promising method for smile reconstruction after facial palsy. International literature lacks a detailed anatomical analysis of the temporalis muscle (TPM) combined with fascia lata (FL) augmentation. This study aims to describe the muscle's properties and calculate the length of FL needed to perform the temporalis muscle flap transfer with FLA. Methods  Twenty nonembalmed male (m) and female (f) hemifacial cadavers were dissected to investigate the temporalis muscle's anatomy. Results  The calculated minimum length of FL needed is 7.03cm (f) and 5.99cm (m). The length of the harvested tendon is 3.16cm/± 1.32cm (f) and 3.18/± 0.73cm (m). The length of the anterior part of the temporalis muscle (aTPM) is 4.16/± 0.80cm (f) and 5.30/± 0.85cm (m). The length of the posterior part (pTPM) is 5.24/± 1.51cm (f) and 6.62/± 1.03cm (m). The length from the most anterior to the most posterior point (aTPMpTPM) is 8.60/± 0.98cm (f) and 10.18/± 0.79cm (m). The length from the most cranial point to the distal tendon (cTPMdT) is 7.90/± 0.43cm (f) and 9.79/± 1.11cm (m). Conclusions  This study gives basic information about the temporalis muscle and its anatomy to support existing and future surgical procedures in their performance. The recommended minimum length of FL to perform a temporalis muscle transfer with FLA is 7.03cm for female and 5.99cm for male, and minimum width of 3 cm. We recommend harvesting some extra centimeters to allow adjusting afterward.

Lower Eyelid Management in Facial Paralysis

Correction of lower eyelid retraction is necessary to restore adequate blink in paralytic lagophthalmos. A plethora of static and dynamic surgical techniques have been described for lower eyelid repositioning. This article provides an approach to management of the paralytic lower eyelid, including a summary of existing techniques, case examples, and surgical technique for in-office lower eyelid suspension using a palmaris longus tendon graft.

Reducing Risk in Facial Reanimation Surgery

Facial reanimation surgery can greatly improve quality of life, but these procedures are not without risk. Important considerations for risk reduction in facial reanimation surgery include preoperative risk-stratification, protecting patients' clinical media, clearly and thoroughly setting expectations, and intraoperative strategies to maximize technical success and minimize operative time.

'Are dynamic procedures superior to static in treating the paralytic eyelid in facial paralysis?'

BACKGROUND

Facial nerve weakness can cause deficient eye closure with reduced corneal protection. Surgical remedies can be static to oppose the levator muscle (lid loading) or dynamic procedures, which act to increase the strength of closure. This retrospective cohort study compares these groups. The hypothesis is that dynamic reconstruction has advantages over static techniques in terms of eye closure, symptomatic improvement, blink restoration, and complication rate.

METHODS

Two cohorts were compared: those treated with a gold weight insertion into the upper eyelid and those who had received dynamic reconstruction. These included temporalis transfer; cross face nerve grafting alone (CFNG) and CFNG followed by free tissue transfer. Assessments included standard photography and video; measurement of eyelid excursion including residual gap and if full eye closure was possible. The presence of the blink reflex and symptoms of dry eye was assessed.

RESULTS

Overall improvement in eye closure was similar with the gold weight compared to dynamic procedures (5.1 mm vs 5.3 mm). Dynamic procedures however gave improved results in terms of symptom relief and restoration of blink. They also had fewer complications and revision rates overall.

CONCLUSION

The study confirms the hypothesis that dynamic reconstructions of the paralysed eyelid confer advantages compared to simple lid loading techniques. Improvements in lid excursion are similar, but symptom improvement and blink restoration are significantly better. A decision regarding eyelid reanimation should be made early in the patient's journey of facial reanimation to allow for accurate planning and placement of nerve grafts at an early stage.

Congenital unilateral lower lip palsy: a case-based review

BACKGROUND

Congenital unilateral lower lip palsy (CULLP), also referred to as congenital asymmetric crying facies (ACF), is a rare condition that causes pronounced depression of the unaffected lower lip when crying, despite symmetric appearance of the mouth and lips at rest. Unlike the acquired form of ACF, CULLP is idiopathic and often involves permanent defect.

METHODS AND RESULTS

We present a case-based review of CULLP, including a thorough analysis of the relevant literature and a discussion of the exemplary case of 5-year-old patient presenting with unilateral facial asymmetry resulting from left-sided facial weakness. The patient was diagnosed with ACF at birth, and documentation from a previous neurologic consultation specifies the root cause of the asymmetry as developmental aplasia of the left depressor anguli oris muscle (DAOM). However, there is no record of electrodiagnostic testing or B-scan ultrasound imaging that would support this conclusion, and the patient's dysarthric speech may suggest lower motor neuron involvement. Botox chemodenervation of the right, unaffected side was recommended to deanimate the contralateral lower lip and achieve facial symmetry, in addition to potentially resolving some of the patient's speech difficulties.

CONCLUSIONS

There are several approaches, both surgical and non-surgical, to the management and correction of CULLP. These include weakening the muscles of the contralateral side or increasing muscular tension on the ipsilateral side, referred to as deanimation and reanimation procedures, respectively.

Supercharge End-to-Side Sensory Transfer to A Long Nerve Graft to Enhance Motor Regeneration in A Brachial Plexus Model—An Experimental Rat Study

Background Long nerve grafts will affect muscle recovery. Aim of this study is to investigate if supercharged end-to-side (SETS) sensory nerve transfer to long nerve graft can enhance functional outcomes in brachial plexus animal model.

Methods A reversed long nerve graft (20–23-mm) was interposed between C6 and musculocutaneous nerve (MCN) in 48 SD rats. The sensory nerves adjacent to the proximal and distal coaptation sites of the nerve graft were used for SETS. There were four groups with 12 rats in each: (A) nerve graft alone, (B) proximal SETS sensory transfer, (C) distal SETS sensory transfer, and (D) combined proximal and distal SETS sensory transfers. Grooming test at 4, 8, 12 and 16 weeks, and compound muscle action potentials (CMAP), biceps tetanic muscle contraction force, muscle weight and MCN axon histomorphologic analysis at 16 weeks were assessed.

Results Grooming test was significantly better in group C and D at 8 weeks (p = 0.02 and p = 0.04) and still superior at 16 weeks. There was no significant difference in CMAP, tetanic muscle contraction force, or muscle weight. The axon counts showed all experimental arms were significantly higher than the unoperated arms. Although the axon count was lowest in group C and highest in group D (p = 0.02), the nerve morphology tended to be better in group C overall.

Conclusion Distal sensory SETS transfer to a long nerve graft showed benefits of functional muscle recovery and better target nerve morphology. Proximal sensory inputs do not benefit the outcomes at all.

Dual-Innervated Free Gracilis Muscle Transfer for Facial Reanimation in Children

BACKGROUND

Facial palsy may have deleterious effects for pediatric patients. The most common reconstruction is 2-stage free gracilis muscle transfer (FGMT) after cross-face nerve graft (CFNG). This requires a prolonged period from time of surgery to smile. New techniques using both a CFNG and motor nerve to masseter (MNM) as dual power sources in a single-stage surgery have been described in adults. Here, we examine our experience with this technique in children.

METHODS

A retrospective study was performed examining patients who underwent dual-innervated single-stage FGMT at 2 pediatric hospitals from 2016 to 2019. Demographics, etiology, perioperative characteristics, time to mandibular and emotional smile, and Sunnybrook scores were recorded.

RESULTS

Five patients met inclusion criteria with a mean age of 11.8 (range, 8-20). Two patients had congenital facial palsy while 3 had acquired facial palsy. Four patients (80%) received dual end-to-end neural coaptations of the CFNG and MNM to the obturator nerve. One (20%) had end-to-side coaptation of the CFNG to the obturator nerve and end-to-end of the MNM to the obturator nerve. The average time to mandibular smile was 103 ± 15.4 days. The average time to emotional smile was 245 ± 48.1 days. The preoperative Sunnybrook scale was 32 ± 7.5 and improved to 55.3 ± 20.6 at 8 months postoperatively.

CONCLUSIONS

Dual-innervated FGMT is effective for facial reanimation in children with unilateral facial palsy. Patients can harness a stronger motor source (MNM) and the component of an emotional stimulus (CFNG). This approach may be the new criterion standard pediatric facial reanimation.

Reverse End-to-Side (Supercharging) Nerve Transfer: Conceptualization, Validation, and Translation

Partial nerve recovery either after expectant observation following an injury in-continuity or after nerve repair is not an uncommon occurrence. Historically, treatment strategies in these situations-late repair, revision repair, or acceptance of a mediocre result-were unsatisfying. The reverse end-to-side, or supercharging, nerve transfer was conceived to offer a more palatable option. Partially validated primarily through small animal research, supercharging has been rapidly translated to clinical practice. Many have extended the indications beyond the original intent, though the final place of this technique in the peripheral nerve surgeon's armamentarium is still yet to be determined.

The Split Hypoglossal Nerve and Cross-Face Nerve Graft for Dual Innervation of the Functional Muscle Transfer in Facial Reanimation

Facial paralysis is a disabling deformity. The affected individual is seriously affected both esthetically and functionally. Free functional muscle transfer is currently the corner stone in the management of long-standing facial nerve paralysis. Several nerve options are available to supply the free muscle transfer. These nerves can be used alone or in combination. The aim of this work is to study the possibility and results of dually innervating the free functioning muscle transfer. The dual innervation is done using the split hypoglossal nerve and cross-face nerve graft (CFNG) both sutured in an end-to-end manner to the nerve to gracilis. Twenty-nine patients with unilateral long-standing facial nerve paralysis (more than 1 y) were treated using free gracilis muscle transfer dually supplied by the split hypoglossal nerve and CFNG, both sutured in an end-to-end manner. The gained excursion after the free gracilis transfer was 9 to 29 mm (mean: 17.24 mm). A statistically significant increase ( P -value=0.0001) in the distance from where the midline crosses the lower vermilion border to commissure occurred from preoperative (mean: 16.55 mm) to postoperative setting (mean: 33.79 mm). Spontaneity was achieved in 26 patients (89.6%). In conclusion, dual innervation of the free muscle transfer using both the split hypoglossal nerve and CFNG (both sutured in an end-to-end manner to the nerve to gracilis) is a good possible option to treat long-standing cases of facial nerve paralysis. It yields adequate muscle excursion with acceptable spontaneity.

Predictors of favorable outcome following hypoglossal-to-facial nerve anastomosis for facial nerve palsy: a systematic review and patient-level analysis of a literature-based cohort

OBJECTIVE

Facial nerve palsy is a debilitating condition that can arise from iatrogenic, traumatic, or congenital causes. One treatment to improve function of the facial muscles after facial nerve injury is hypoglossal-to-facial nerve anastomosis (HFA). HFA's efficacy and predictors of its success vary in the literature. Here, the authors present a patient-level analysis of a literature-based cohort to assess outcomes and investigate predictors of success for HFA.

METHODS

Seven electronic databases were queried for studies providing baseline characteristics and outcomes of patients who underwent HFA. Postoperative outcomes were measured using the House-Brackmann (HB) grading scale. A change in HB grade of 3 points or more was classified as favorable. A cutoff value for time to anastomosis associated with a favorable outcome was determined using the Youden Index.

RESULTS

Nineteen articles with 157 patients met the inclusion criteria. The mean follow-up length was 27.4 months, and the mean time to anastomosis after initial injury was 16 months. The end-to-side and end-to-end anastomosis techniques were performed on 84 and 48 patients, respectively. Of the 130 patients who had available preoperative and postoperative HB data, 60 (46.2%) had a favorable outcome. Time from initial injury to anastomosis was significantly different between patients with favorable and unfavorable outcomes (7.3 months vs 29.2 months, respectively; p < 0.001). The optimal cutoff for time to anastomosis to achieve a favorable outcome was 6.5 months (area under the curve 0.75). Patients who underwent anastomosis within 6.5 months of injury were more likely to achieve a favorable outcome (73% vs 31%, p < 0.001).

CONCLUSIONS

HFA is an effective method for restoring facial nerve function. Favorable outcomes for facial nerve palsy may be more likely to occur when time to anastomosis is within a 6.5-month window.

Contribution and safety of the side-to-end hypoglossal-to-facial transfer in multidisciplinary facial reanimation

BACKGROUND

This study evaluates facial and tongue function in patients undergoing side-to-end hypoglossal-to-facial transfer (HFT) with additional techniques.

METHODS

Thirty-seven patients underwent a side-to-end HFT. Twelve had additional cross-face grafts, and 9 had an additional masseter-to-facial transfer. Facial was assessed with House-Brackmann (HB), Sunnybrook Facial Grading Scale (SFGS), and eFACE. Martins scale and the Oral-Pharyngeal Disability Index (OPDI) were used to assess tongue function.

RESULTS

Ninety-four percent of cases reached HB grades III-IV. Mean total SFGS score improved from 16 ± 15 to 59 ± 11, while total eFACE score from 52 ± 13 to 80 ± 5. Dual nerve transfers were a predictor for a better eFACE total score p = 0.034, β = 2.350 [95% CI, 0.184-4.516]), as well as for a higher SFGS total score (p = 0.036, β = 5.412 [95% CI, 0.375-10.449]). All patients had Martin's grade I. Mean postoperative OPDI scores were 84 ± 17 (local physical), 69 ± 16 (simple and sensory motor components), 82 ± 14 (complex functions), and 73 ± 22 (psychosocial).

CONCLUSIONS

The side-to-end HFT offers predictable facial function outcome and preserves tongue function in nearly all cases. Dual nerve transfers appear to improve the final outcome.

A Comprehensive Approach to Facial Reanimation: A Systematic Review

Purpose: To create a systematic overview of the available reconstructive techniques, facial nerve grading scales, physical evaluation, the reversibility of paralysis, non-reconstructive procedures and medical therapy, physical therapy, the psychological aspect of facial paralysis, and the prevention of facial nerve injury in order to elucidate the gaps in the knowledge and discuss potential research aims in this area. A further aim was to propose an algorithm simplifying the selection of reconstructive strategies, given the variety of available reconstructive methods and the abundance of factors influencing the selection. Methodological approach: A total of 2439 papers were retrieved from the Medline/Pubmed and Cochrane databases and Google Scholar. Additional research added 21 articles. The primary selection had no limitations regarding the publication date. We considered only papers written in English. Single-case reports were excluded. Screening for duplicates and their removal resulted in a total of 1980 articles. Subsequently, we excluded 778 articles due to the language and study design. The titles or abstracts of 1068 articles were screened, and 134 papers not meeting any exclusion criterion were obtained. After a full-text evaluation, we excluded 15 papers due to the lack of information on preoperative facial nerve function and the follow-up period. This led to the inclusion of 119 articles. Conclusions: A thorough clinical examination supported by advanced imaging modalities and electromyographic examination provides sufficient information to determine the cause of facial palsy. Considering the abundance of facial nerve grading scales, there is an evident need for clear guidelines regarding which scale is recommended, as well as when the postoperative evaluation should be carried out. Static procedures allow the restoral of facial symmetry at rest, whereas dynamic reanimation aims to restore facial movement. The modern approach to facial paralysis involves neurotization procedures (nerve transfers and cross-facial nerve grafts), muscle transpositions, and microsurgical free muscle transfers. Rehabilitation provides patients with the possibility of effectively controlling their symptoms and improving their facial function, even in cases of longstanding paresis. Considering the mental health problems and significant social impediments, more attention should be devoted to the role of psychological interventions. Given that each technique has its advantages and pitfalls, the selection of the treatment approach should be individualized in the case of each patient.

Spinal motor neuron transplantation to enhance nerve reconstruction strategies: Towards a cell therapy

Nerve transfers have become a powerful intervention to restore function following devastating paralyzing injuries. A major limitation to peripheral nerve repair and reconstructive strategies is the progressive, fibrotic degeneration of the distal nerve and denervated muscle, eventually precluding recovery of these targets and thus defining a time window within which reinnervation must occur. One proven strategy in the clinic has been the sacrifice and transfer of an adjacent distal motor nerve to provide axons to occupy, and thus preserve (or "babysit"), the target muscle. However, available nearby nerves are limited in severe brachial plexus or spinal cord injury. An alternative and novel proposition is the transplantation of spinal motor neurons (SMNs) derived from human induced pluripotent stem cells (iPSCs) into the target nerve to extend their axons to occupy and preserve the targets. These cells could potentially be delivered through minimally invasive or percutaneous techniques. Several reports have demonstrated survival, functional innervation, and muscular preservation following transplantation of SMNs into rodent nerves. Advances in the generation, culture, and differentiation of human iPSCs now offer the possibility for an unlimited supply of clinical grade SMNs. This review will discuss the previous reports of peripheral SMN transplantation, outline key considerations, and propose next steps towards advancing this approach to clinic. Stem cells have garnered great enthusiasm for their potential to revolutionize medicine. However, this excitement has often led to premature clinical studies with ill-defined cell products and mechanisms of action, particularly in spinal cord injury. We believe the peripheral transplantation of a defined SMN population to address neuromuscular degeneration will be transformative in augmenting current reconstructive strategies. By thus removing the current barriers of time and distance, this strategy would dramatically enhance the potential for reconstruction and functional recovery in otherwise hopeless paralyzing injuries. Furthermore, this strategy may be used as a permanent axon replacement following destruction of lower motor neurons and would enable exogenous stimulation options, such as pacing of transplanted SMN axons in the phrenic nerve to avoid mechanical ventilation in high cervical cord injury or amyotrophic lateral sclerosis.

Facial reanimation using the hypoglossal nerve and ansa cervicalis: a short-term retrospective analysis of surgical outcomes

Background

Transferring the hypoglossal nerve to the facial nerve using an end-to-end method is very effective for improving facial motor function. However, this technique may result in hemitongue atrophy. The ansa cervicalis, which arises from the cervical plexus, is also used for facial reanimation. We retrospectively reviewed cases where facial reanimation was performed using the ansa cervicalis to overcome the shortcomings of existing techniques of hypoglossal nerve transfer.

Methods

The records of 15 patients who underwent hypoglossal nerve transfer were retrospectively reviewed. Three methods were used: facial reanimation with hypoglossal nerve transfer (group 1), facial nerve reanimation using the ansa cervicalis (group 2), and sural nerve interposition grafting between the hypoglossal nerve and facial nerve (group 3). In group 1, the ansa cervicalis was coapted to neurotize the distal stump of the hypoglossal nerve in a subset of patients. Clinical outcomes were evaluated using the House-Brackmann (H-B) grading system and Emotrics software.

Results

All patients in group 1 (n = 4) achieved H-B grade IV facial function and showed improvements in the oral commissure angle at rest (preoperative vs. postoperative difference, 6.48° ± 0.77°) and while smiling (13.88° ± 2.00°). In groups 2 and 3, the oral commissure angle slightly improved at rest (group 2: 0.95° ± 0.53°, group 3: 1.35° ± 1.02°) and while smiling (group 2: 2.06° ± 0.67°, group 3: 1.23° ± 0.56°). In group 1, reduced tongue morbidity was found in patients who underwent ansa cervicalis transfer.

Conclusion

Facial reanimation with hypoglossal nerve transfer, in combination with hypoglossal nerve neurotization using the ansa cervicalis for complete facial palsy patients, might enable favorable facial reanimation outcomes and reduce tongue morbidity. Facial reanimation using the ansa cervicalis or sural nerve for incomplete facial palsy patients did not lead to remarkable improvements, but it warrants further investigation.

Seminal Studies in Facial Reanimation Surgery: Consensus and Controversies in the Top 50 Most Cited Articles

ABSTRACT

Facial paralysis can impair one's ability to form facial expressions that are congruent with internal emotion. This hinders communication and the cognitive processing of emotional experience. Facial reanimation surgery, which aims to restore full facial expressivity is a relatively recent undertaking which is still evolving. Due in large part to published techniques, refinements, and clinical outcomes in the scientific literature, consensus on best practice is gradually emerging, whereas controversies still exist.Taking stock of how the discipline reached its current state can help delineate areas of agreement and debate, and more clearly reveal a path forward. To do this, the authors have analyzed the 50 seminal publications pertaining to facial reanimation surgery. In longstanding cases, the free gracilis transfer emerges as a clear muscle of choice but the nerve selection remains controversial with prevailing philosophies advocating cross facial nerve grafts (with or without the support of an ipsilateral motor donor) or an ipsilateral motor donor only, of which the hypoglossal and nerve to masseter predominate. The alternative orthodoxy has refined the approach popularized by Gillies in 1934 and does not require the deployment of microsurgical principles. Although this citation analysis does not tell the whole story, surgeons with an interest in facial reanimation will find that this is a good place to start.

A supportive donor nerve for long-term facial paralysis: Anatomical analysis of the posterior auricular nerve and micro-anatomical comparison with zygomatic nerve

BACKGROUND

The posterior auricular nerve (PAN) is an inspiring candidate for the additional axonal source in long-term facial paralysis to improve the functional results of the cross-facial nerve (FN) graft technique. However, no studies have analyzed the PAN's axonal load and its microscopic anatomy to assess its utilization in facial reanimation. The present study aims to examine the anatomical and microscopic features of the PAN to analyze its feasibility as a donor nerve.

METHODS

The bilateral facial side of 14 fresh frozen adult human cadavers was examined for the study. The PAN's anatomical course was recorded, and nerve specimens from the PAN and zygomatic nerve (ZN) were obtained to compare their microscopic anatomy and axon counts using a light microscope and transmission electron microscope.

RESULTS

The PAN's average branching distance and its course length were 5.8 ± 2.69 mm and 59.2 ± 5.85, respectively. The mean number of myelinated axons was 600.28 ± 69.97 in the PAN and 728.85 ± 166.31 in the ZN. This difference between the two nerves was statistically significant (p = 0.002). However, considering the gender variable, the mean axon counts of PAN and ZN were statistically similar for face sides and their average. Furthermore, the ultrastructural anatomy of both nerves was similar in electron microscopic evaluation.

CONCLUSIONS

The present study confirms that the PAN is a proper candidate to be a supportive donor nerve due to its isolated site, consistent anatomical course, convenient ultrastructural anatomy as well as axonal load.

[Babysitter nerve transfer from the thenar branch to the deep terminal branch of the ulnar nerve : An option to preserve the intrinsic hand muscles in proximal lesions of the ulnar nerve]

Operationsziel

Ziel dieser Operation ist eine frühzeitige Innervation der intrinsischen Handmuskulatur durch Fasern des N. medianus, um einer irreversiblen Atrophie des Muskelgewebes vorzubeugen. Der Nerventransfer erfolgt mittels Babysitter-Interponat, welches jeweils End-zu-Seit an Spender- und Empfängernerv koaptiert wird. Der Eingriff wird kombiniert mit einer proximalen Rekonstruktion des N. ulnaris.

Indikationen

Hochgradige Läsionen des N. ulnaris ohne spontane Regeneration, insbesondere bei proximaler Läsionshöhe und/oder später Patientenvorstellung.

Kontraindikationen

Irreversible Denervation der intrinsischen Muskulatur; Schwäche oder Ausfall des R. thenaris.

Operationstechnik

Der Zugang erfolgt über dem beugeseitigen Handgelenk durch eine longitudinale Inzision. Der R. profundus des N. ulnaris sowie der R. thenaris des N. medianus werden nach Spalten des Retinaculum flexorum dargestellt. Es erfolgt eine Verbindung der beiden Nerven über ein autologes Interponat, welches jeweils in End-zu-Seit-Manier über ein epineurales Fenster an den Spender- (R. thenaris) und den Empfängernerv (R. profundus) koaptiert wird. Dies ermöglicht die zeitgerechte Regeneration einiger motorischer Medianusaxone in die intrinsische Muskulatur, um einer irreversiblen Degeneration vorzubeugen. Aufgrund der End-zu-Seit-Nervennaht wird der Schaden des Spendernervs auf ein Minimum reduziert. Durch die gleichzeitig durchgeführte Rekonstruktion des N. ulnaris auf Höhe der Läsion wird im späteren Verlauf auch eine autochthone Reinnervation der intrinsischen Muskulatur ermöglicht.

Weiterbehandlung

Postoperativ werden Laschen eingebracht und ein steriler Handverband angelegt. Erster Verbandswechsel und Zug der Laschen am ersten postoperativen Tag, Nahtentfernung in der Regel nach 2 Wochen. Bereits nach 1 Woche kann die ergotherapeutische Beübung zum Erhalt der Gelenkbeweglichkeit erfolgen. Nach den ersten Zeichen der motorischen und/oder sensiblen Reinnervation erfolgt eine zielgerichtete Physiotherapie zum Wiedererlernen der alltäglichen Handfunktion.

Ergebnisse

Diese Technik wurde bisher an 3 Patienten mit hochgradiger Läsion des N. ulnaris vorgestellt. Bei einer Follow-up-Zeit von 6 Jahren konnten alle Patienten Muskelkraft von ≥ M3 erlangen, mit allgemein gutem bis exzellentem Ergebnis anhand der modifizierten Bishop Rating Scale.

[Nerve transposition (nerve transfer): development and principles]

This review article presents the history, indications and techniques for the usual nerve transpositions in the upper extremities. By means of nerve transposition paralyzed muscles are reinnervated using dispensable donor motor axons. Many standard operations on the upper extremities are attributable to concepts of German-speaking surgeons and orthopedists. The reliable return of function by the short-range and selective motor reinnervation using nerve transfer results in a renaissance of these techniques. The spectrum of applications has been substantially extended in recent years. In order to achieve an optimal result, a subtle microsurgical technique is necessary. In this way excellent results can be achieved even for complex proximal nerve injuries.

Strategies to Improve Cross-Face Nerve Grafting in Facial Paralysis

Cross-face nerve grafting enables the reanimation of the contralateral hemiface in unilateral facial palsy and may recover a spontaneous smile. This chapter discusses various clinically applicable strategies to increase the chances for good functional outcomes by maintaining the viability of the neural pathway and target muscle, increasing the number of reinnervating nerve fibers and selecting functionally compatible donor nerve branches. Adopting those strategies may help to further improve patient outcomes in facial reanimation surgery.

Peripheral Nerve Healing: So Near and Yet So Far

Peripheral nerve injuries represent a considerable portion of chronic disability that especially affects the younger population. Prerequisites of proper peripheral nerve injury treatment include in-depth knowledge of the anatomy, pathophysiology, and options in surgical reconstruction. Our greater appreciation of nerve healing mechanisms and the development of different microsurgical techniques have significantly refined the outcomes in treatment for the past four decades. This work reviews the peripheral nerve regeneration process after an injury, provides an overview of various coaptation methods, and compares other available treatments such as autologous nerve graft, acellular nerve allograft, and synthetic nerve conduits. Furthermore, the formation of neuromas as well as their latest treatment options are discussed.

Combined Sequential Bilateral Hypoglossal-to-facial and Masseter-to-facial Transfers for Bilateral Facial Paralysis

Bilateral facial paralysis is a challenging situation requiring complex management. Surgical treatment can include nerve transfers, mainly masseter-to-facial, or muscle transfers, gracilis free flap, or temporalis transposition. Deciding on the surgical option depends on the duration of the paralysis and the feasibility of facial muscles. We present the case of a 10-year-old child with permanent bilateral facial paralysis after brainstem tumor surgery. The patient was treated with bilateral simultaneous hypoglossal-to-facial transfer followed by bilateral simultaneous masseter-to-facial 12 months later. After 23 months of follow-up and specific physical therapy, she has good and symmetric resting tone, complete eye closure, moderate bilateral smile excursion, mild lip pucker movement, and good oral competence. The combination of these two nerve transfers, when possible, gives the opportunity of restoring movement taking the best of each technique, with acceptable results and no significant clinical deficits in the donor sites.

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

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

Facial Nerve Repair: Bioengineering Approaches in Preclinical Models

Injury to the facial nerve can occur after different etiologies and range from simple transection of the branches to varying degrees of segmental loss. Management depends on the extent of injury and options include primary repair for simple transections and using autografts, allografts, or conduits for larger gaps. Tissue engineering plays an important role to create artificial materials that are able to mimic the nerve itself without extra morbidity in the patients. The use of neurotrophic factors or stem cells inside the conduits or around the repair site is being increasingly studied to enhance neural recovery to a greater extent. Preclinical studies remain the hallmark for development of these novel approaches and translation into clinical practice. This review will focus on preclinical models of repair after facial nerve injury to help researchers establish an appropriate model to quantify recovery and analyze functional outcomes. Different bioengineered materials, including conduits and nerve grafts, will be discussed based on the experimental animals that were used and the defects introduced. Future directions to extend the applications of processed nerve allografts, bioengineered conduits, and cues inside the conduits to induce neural recovery after facial nerve injury will be highlighted.

Fascicular Turnover Flap: An Approach for Facial Nerve Reconstruction

ABSTRACT

Facial nerve injuries are a common complication associated with parotidectomy. These functionally debilitating injuries are conventionally treated with nonvascularized nerve grafting; however, this reconstructive modality produces moderate donor site morbidity and has limited efficacy for repairing large defects. In addition, nonvascularized nerve grafts are highly susceptible to radiotherapy and require a well-vascularized wound bed to produce adequate therapeutic results. The fascicular turnover flap, described by Koshima et al, utilizes a single fascicle to bridge two nerve endings that are in series with no donor site morbidity. Although studies have demonstrated this technique's efficacy, there is a paucity of data regarding its use in patients undergoing facial nerve reconstruction. Herein, we describe our early clinical experience using the fascicular turnover flap to reconstruct branches of the facial nerve in patients undergoing extensive parotidectomy. Our patients underwent successful reconstruction of the nerve defects produced by parotidectomy using the fascicular turnover flap. Despite postoperative radiotherapy, both patients demonstrated complete functional recovery at six months postoperatively. Although formal head-to-head studies are needed to compare the outcomes of this technique versus conventional nerve grafting for facial nerve reconstruction, our preliminary experiences suggest that the fascicular turnover flap is a viable modality of reconstruction with great potential.

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

BACKGROUND

This study describes a different approach with a 2-stage facial reanimation in patients with long-standing unilateral facial paralysis using free gracilis muscle transfer, innervated by both cross-facial nerve graft and masseteric nerve. The authors present their rationale, surgical technique, and long-term outcomes.

METHODS

Between August 2012 and March 2016, 11 patients (6 female and 5 male patients) underwent a 2-staged dually innervated gracilis muscle transfer. Patients were evaluated with physical examination and needle electromyography. A standardized assessment of preoperative and postoperative photographs and videos was performed using Terzis' smile functional grading system at 48 months following surgery and the Emotrics software to assess improvement in symmetry over a 36-month postoperative period.

RESULTS

Voluntary contraction of the gracilis muscle was observed in all patients at a mean of 4 months and 4 days following muscle transfer. A spontaneous smile produced without teeth clenching was developed in all patients by 18 months postoperatively. Six patients achieved excellent and 5 good results. The difference between the averaged pre- and postoperative scores was statistically significant. With Emotrics, there were significant improvements in the smile angle, upper lip elevation, commissural excursion, and commissural height, with continuous improvement over 36 months. The postoperative electromyography (EMG) confirmed dual innervation of the gracilis muscle by the facial and masseteric donor motor neural sources. We present our results at minimum 48 months postoperatively.

CONCLUSIONS

Dual innervated two-stage gracilis transfer is an effective method for reanimation in long-standing unilateral facial paralysis, providing both rapid reinnervation of the transferred muscle, together with a powerful, synchronous smile.

Lower Lip Reanimation: Experience Using the Anterior Belly of Digastric Muscle in 2-stage Procedure

Supplemental Digital Content is available in the text.

Background:

Lower lip depression was historically regarded a neglected area of facial paralysis, but, with refinement of techniques, has gained increasing attention. We present the first detailed description and evaluation of a 2-stage technique, using first cross facial nerve graft and then the anterior belly of digastric muscle (ABDM), innervated by the cross facial nerve graft, to restore dynamic and spontaneous lower lip depression.

Methods:

Retrospective analysis of 2-stage lower lip reanimations between 2010 and 2018 was performed. Demographics, etiology, and operative details were recorded. Videos were graded pre/postoperatively using a 5-point Likert scale by 21 independent observers. Objective changes of symmetry were analyzed using Photogrammetry (Emotrics).

Results:

Twenty-seven patients were identified (median age 34.9 years, range 6–64). The mean duration between the 2 stages was 15.1 months. Follow-up ranged from 18–72 months. There were minor complications in 4 patients, and 1 case was abandoned due to insufficient length of anterior belly of digastric muscle. Average peer-reviewed scores improved from 2.1 to 3.2 (P < 0.05). Emotrics did not show improvement in static symmetry (P > 0.05). However, during open-lip smiling, lower lip height improved significantly (P < 0.05) whilst dental show improvements approached significance (P < 0.08). Lower lip symmetry was also improved during lower lip depression, as shown by improvements in lower lip height (P < 0.05), smile angle, and dental show (both P < 0.05).

Conclusions:

These results show the safety and efficacy of 2-stage lower lip reanimation using anterior belly of digastric muscle transposition. This procedure is our choice for longstanding lower lip paralysis and provides coordinated spontaneous lower lip depression, thus enhancing the overall perioral animation and smile.

End-to-Side Anterior Interosseous Nerve Transfer: A Valuable Alternative for Traumatic High Ulnar Nerve Palsy

BACKGROUND

The prognosis of high ulnar nerve injury is poor despite nerve repair or grafting. Anterior interosseous nerve (AIN) transfers provide a satisfactory recovery. However, the efficacy of end-to-side (ETS) AIN transfer and optimal timing in Sunderland grade IV/V of high ulnar nerve injury is lacking.

OBJECTIVE

The goals were to compare the outcomes of high ulnar nerve injury managed with ETS AIN transfers with those managed with conventional procedures (nerve repair or graft only) and identify differences between early and delayed transfers.

METHODS

Patients with isolated high ulnar nerve injury (Sunderland grade IV/V) from 2010 to 2017 were recruited. Patients with conventional treatments and AIN transfers were designated as the control and AIN groups, respectively. Early transfer was defined as the AIN transfer performed within 8 weeks postinjury. Outcomes were measured and analyzed by the British Medical Research Council (BMRC) score, grip strength, and pinch strength.

RESULTS

A total of 24 patients with high ulnar nerve injury (Sunderland grade IV/V) were included. There were 11 and 13 patients in the control and AIN groups, respectively. In univariate analysis, both early and delayed AIN transfers demonstrated significantly better motor recovery among BMRC score and strength of grip and pinch at 12 months (P < 0.05). No statistical significance was found between early and delayed transfer. In multivariate analysis, both early and delayed transfers were regarded as strong and independent factors for motor recovery of ulnar nerve. Compared with the control, early [odds ratio (OR), 1.83; P < 0.001] and delayed (OR, 1.59; P < 0.001) transfers showed significant improvement with regard to BMRC scores. The pinch strength in early (OR, 31.68; P < 0.001) and delayed (OR, 26.45; P < 0.001) transfers was also significantly better.

CONCLUSION

The ETS AIN transfer, in either early or delayed fashion, significantly improved intrinsic motor recovery in high ulnar nerve injuries classified as Sunderland grade IV/V. The early transfer group demonstrated a trend toward better functional recovery with less downtime.

Progress in facial reinnervation

Facial nerve injury often results in facial paralysis, which seriously affects the patients both aesthetically and functionally. Facial nerve reinnervation methods, including direct anastomosis, nerve graft, nerve transposition, cross-facial nerve graft, and combined surgeries, have recently become a hot topic with many new procedures being explored. This study summarizes the relevant literatures and discusses the scope of application, advantages, and disadvantages of the different methods. The treatment options or combined surgeries for facial nerve reinnervation should be individualized for specific patients to achieve the best reanimation outcome with good static symmetry, facial tone, and spontaneous, natural, symmetrical, and strong facial movements.

Masseter nerve-based facial palsy reconstruction

Facial paralysis is a devastating disease, the treatment of which is challenging. The use of the masseteric nerve in facial reanimation has become increasingly popular and has been applied to an expanded range of clinical scenarios. However, appropriate selection of the motor nerve and reanimation method is vital for successful facial reanimation. In this literature review on facial reanimation and the masseter nerve, we summarize and compare various reanimation methods using the masseter nerve. The masseter nerve can be used for direct coaptation with the paralyzed facial nerve for temporary motor input during cross-facial nerve graft regeneration and for double innervation with the contralateral facial nerve. The masseter nerve is favorable because of its proximity to the facial nerve, limited donor site morbidity, and rapid functional recovery. Masseter nerve transfer usually leads to improved symmetry and oral commissure excursion due to robust motor input. However, the lack of a spontaneous, effortless smile is a significant concern with the use of the masseter nerve. A thorough understanding of the advantages and disadvantages of the use of the masseter nerve, along with careful patient selection, can expand its use in clinical scenarios and improve the outcomes of facial reanimation surgery.

Masseter-to-Facial Cranial Nerve Anastomosis: A Report of 30 Cases

BACKGROUND

Facial nerve paralysis (FP) is a possible complication of cerebellopontine angle tumor surgery. Several donor nerves have been used in the past for facial reanimation. We report the results of 30 cases of masseter-to-facial anastomosis.

OBJECTIVE

To prospectively evaluate the efficacy of V to VII anastomosis after FP.

METHODS

In a prospective study, we included 30 consecutive patients with FP (20 women and 10 men) whose mean age was 48.8 yr (32-76 yr). In almost all cases, FP developed after cerebellopontine angle tumor surgery (29 patients), whereas in one case, FP occurred after skull base trauma. Pre- and postoperative evaluation of facial nerve function was performed using the House-Brackmann (HB) scale and the Sokolovsky scale, as well as by electromyography. Follow-up ranged from 11 to 51 mo and averaged 22 mo.

RESULTS

All patients achieved functional recovery of the facial nerve from VI to either III or IV HB degree. Patients with short time FP showed significantly better postoperative recovery.

CONCLUSION

The results of the V to VII anastomosis demonstrate a significant improvement of facial nerve function and virtually no complications.