Hypoglossal-facial nerve interpositional-jump graft for facial reanimation without tongue atrophy

Reanimation Techniques of Peripheral Facial Paralysis: A Comprehensive Review Focusing on Surgical and Bioengineering Approaches

Peripheral facial paralysis represents a disabling condition with serious psychological and social impact. Patients with peripheral facial paralysis have a disfigurement of the face with loss of harmony and symmetry and difficulties in everyday facial functions such as speaking, drinking, laughing, and closing their eyes, with impairment of their quality of life. This paralysis leads to impairment of facial expression, which represents one of the first means of communication, an important aspect of human interaction. This review aims to explore the reanimation techniques for managing peripheral facial paralysis. An analysis of static and dynamic techniques for facial reanimation is provided, including muscle flaps, nerve grafting techniques, and bioengineering solutions. Each technique showed its benefits and drawbacks; despite several options for facial reanimation, no technique has been detected as the gold standard. Therefore, each patient must be evaluated on an individual basis, considering their medical history, age, expectations, and treatment goals, to find the best and most fitting treatment.

An Updated Evaluation of the Management of Nerve Gaps: Autografts, Allografts, and Nerve Transfers

Within the past decade, there have been multiple innovations in the field of nerve surgery. In this review, we highlight critical changes and innovations that have helped advance the field and present opportunities for further study. This includes the modification and clarification of the classification schema for nerve injuries which informs prognosis and treatment, and a refined understanding and application of electrodiagnostic studies to guide patient selection. We provide indications for operative intervention based on this nerve injury classification and propose strategies best contoured for varying injury presentations at differing time points. Lastly, we discuss new developments in surgical techniques and approaches based on these advancements.

Masseteric-facial anastomosis and hypoglossal-facial anastomosis after lateral skull base and middle ear surgery

INTRODUCTION

Lateral skull base (LSB) and middle ear pathologies often involve the facial nerve (FN), and their treatment may require FN sacrifice. Cases with unidentifiable proximal stump or intact FN with complete FN palsy, necessitate FN anastomosis with another motor nerve in order to restore innervation to the mimicking musculature. The results of hypoglossal-to-facial nerve anastomosis (HFA) and masseteric-facial nerve anastomosis in patients with facial paralysis after middle ear and LSB surgeries, are presented and compared.

METHODS

Adult patients with total definitive facial paralysis after middle ear or LSB surgery undergoing facial nerve reanimation through hypoglossal or masseteric transfer anastomosis were enrolled. The facial nerve function was graded according to the House Brackmann grading system (HB). The facial function results at 3 months, 6 months, 12 months, 18 months and at the last follow up (more than 18 months) are compared.

RESULTS

153 cases of LSB and middle ear surgery presented postoperative facial palsy and underwent facial nerve reanimation surgery with HF in 85 patients (55.5%) and MF in 68 patients (44.5%). The duration of the FN palsy before reconstructive surgery was inversely associated to better FN results, in particular with having a grade III HB (p = 0.003). Both techniques had significantly lower HB scores when an interval between palsy onset and reanimation surgery was 6 months or less (MF p = 0.0401; HF p = 0.0022). Patients who underwent a MF presented significant improvement of the FN function at 3 months from surgery (p = 0.0078). At the last follow-up, 63.6% recovered to a grade III HB and 22.7% to a grade IV. On the other hand, the first significant results obtained in the HF group were at 6 months from surgery (p < 0.0001). 67.8% of patients had a grade III HB after a HF at the last follow-up, 28.8% a grade IV. FN grading at 6 months from surgery was significantly lower in the MF group compared to the HF (p = 0.0351). The two techniques had statistically similar results at later follow-up evaluations.

DISCUSSION/CONCLUTION

MF was associated to initial superior results, presenting significant facial recovery at 3 months, and significantly better functional outcomes at 6 months from surgery compared to HF. Although later results were not significantly different in this study, earlier results have an important role in order to limit the duration of risk of corneal exposure.

Surgical results for one-stage VII/VIII schwannoma resection and hemihypoglossal-facial neurorrhaphy

BACKGROUND

This retrospective study evaluated the outcomes of patients undergoing one-stage resection of VII/VIII schwannomas and hemihypoglossal-facial neurorrhaphy via the translabyrinthine approach (TLA).

METHODS

The study encompassed ten consecutive patients with unilateral hearing loss (six women, four men, mean age: 49.5 ± 12.1 years) who underwent surgery. The cohort included two patients with vestibular schwannomas (VSs), four with facial nerve schwannomas (FNSs) (two originating from the geniculate ganglion of the facial nerve and two from the cerebellopontine angle), one with VS regrowth, and three with residual VSs. Preoperative facial nerve function, assessed using the House-Brackmann (HB) scale, was Grade V in one and Grade VI in nine patients. The mean preoperative duration of facial paralysis was 7.5 ± 6.9 months.

RESULTS

All patients underwent gross total resection. Postoperatively, one patient experienced cerebrospinal fluid leaks, which were successfully managed with lumbar drains and surgical revisions. At follow-up, facial nerve function improved in all patients: HB Grade V to III in one, HB Grade VI to III in one, HB Grade VI to IV in seven, and Grade VI to V in one. No tumor recurrence was observed during the follow-up period (mean duration: 16.6 ± 9.3 months), and no patient had hemilingual atrophy.

CONCLUSION

The TLA for one-stage resection of VII/VIII schwannomas and facial nerve reconstruction is effective in treating both regrowth and residual VSs and FNSs in the cerebellopontine angle or petrosal bone in patients with severe preoperative facial palsy. This technique facilitates simultaneous tumor removal and nerve anastomosis, thereby reducing the need for multiple surgical interventions in patients with hearing loss and compromised facial nerve function.

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.

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.

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.

Effectiveness of Hypoglossal-Facial Anastomosis in the Rehabilitation of Facial Paralysis Following Vestibular Schwannoma Surgery: A Systematic Review

The facial nerve plays a crucial role in facial expression and sensory functions, with irreversible injuries often demanding rehabilitation therapies, with hypoglossal-facial nerve anastomosis (HFA) being one of the treatment options. This systematic review assessed different HFA techniques for facial paralysis, particularly post vestibular schwannoma resection, focusing on effectiveness and associated morbidities. Fifteen studies, comprising a case series and a retrospective cohort, were analyzed. Techniques included end-to-end, split, side-to-side, end-to-side, and jump interpositional graft hypoglossal-facial anastomosis (JIGHFA). Positive outcomes were observed with end-to-end and side-to-side techniques, while the split technique and JIGHFA showed promise. Comparative analyses favored the 'end-to-side' approach. Shorter intervals between surgery and HFA correlated with improved outcomes. Methodological variations highlight the need for prospective studies with standardized methodologies for robust evidence and informed decision-making on optimal HFA techniques.

Hypoglossal Nerve Transfer for Facial Nerve Paralysis: A Systematic Review and Meta-Analysis

Background: Hypoglossal-facial nerve (12-7) anastomosis can restore symmetry and voluntary movement on the face in patients with facial nerve paralysis. Traditional 12-7 transfer includes direct end-to-end nerve anastomosis, sacrificing the entire hypoglossal nerve. Contemporary, end-to-side anastomosis, or split anastomosis techniques limit tongue morbidity by preserving some hypoglossal nerve. Direct outcome comparisons between these techniques are limited. Objective: To compare reported outcomes of facial movement, tongue, speech, and swallow outcomes among the different types of hypoglossal-facial nerve anastomosis schemes. Evidence Review: For this systematic review and meta-analysis, a comprehensive strategy was designed to search PubMed, Scopus, and the Cochrane Database from inception to January 2021, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, reporting guideline yielding 383 results. Any participant who underwent 12-7 transfer using any of the three techniques, with or without an interposition graft, and had documented preoperative and postoperative evaluation of facial nerve function with a validated instrument such as House-Brackmann (HB), was considered for inclusion. Secondary outcomes of synkinesis, tongue atrophy, and speech or swallowing dysfunction were also compared. Forty-nine studies met inclusion criteria, representing data from 961 total patients who underwent 12-7 transfer. Results: The proportion of good HB outcomes (HB I-III) did not differ by anastomosis type: End-to-side and end-to-end anastomosis (73% vs. 59%, p = 0.07), split and end-to-end anastomosis (62% vs. 59%, p = 0.88), and end-to-side anastomosis and split anastomosis (73% vs. 62%, p = 0.46). There was no difference in reported synkinesis rates between the anastomosis types. However, end-to-side anastomosis (z = 6.55, p < 0.01) and split anastomosis (z = 3.58, p < 0.01) developed less tongue atrophy than end-to-end anastomosis. End-to-side anastomosis had less speech/swallowing dysfunction than end-to-end anastomosis (z = 3.21, p < 0.01). Conclusion: End-to-side and split anastomoses result in similar HB facial nerve outcomes as the traditional end-to-end 12-7 anastomosis. End-to-side anastomosis has decreased complications of tongue atrophy and speech/swallow dysfunction compared to end-to-end anastomosis. In addition, split anastomosis has decreased rates of tongue atrophy compared to end-to-end anastomosis.

Dynamic Surgical Restoration of Mid and Lower Facial Paralysis: A Single-Greek-Centre Experience

Background Facial palsy detrimentally impacts an individual's quality of life due to its effects on function and appearance. There are several reconstructive surgical techniques available that aim to restore facial symmetry. Techniques such as direct neurorrhaphy, nerve grafts, dual reanimation, and reinnervation have the potential to enable varying motor functions, including the re-establishment of a dynamic smile. This study aimed to assess the outcomes of facial palsy reconstructive surgeries undertaken at a tertiary care centre for facial nerve reconstruction in Athens. Methods This study consisted of a comprehensive case series showcasing the outcomes of facial palsy reconstructive surgeries on 29 patients at our Tertiary General Oncological Anti-Cancer Hospital of Athens 'Agios Savvas'. The surgical procedures from October 2004 to December 2023 included reinnervation, nerve grafting, free muscle transfer, and myoplasties following our recommended algorithm. We categorized the patients into two groups: Group A and Group B based on the timing of the reconstruction: delayed or immediate. The House-Brackmann grading scale evaluated the degree and improvement of facial paralysis. Results In Group A, two of the seven patients exhibited activation of the mimetic musculature immediately postsurgery, while the remaining five experienced enhanced facial nerve function in the subsequent months. Adverse outcomes were temporalis dysfunction in one case and tongue atrophy in another. Conversely, in Group B, 21 of 22 patients demonstrated facial activation immediately postsurgery. Only one patient from this group did not show any facial nerve function postoperatively. Two of the 22 patients in Group B encountered complications: one with trismus and another with temporalis dysfunction. All patients were observed for a minimum of 12 months postsurgery. Conclusion With the exception of one patient, all participants showed improved postoperative results, which were satisfactory when weighed against the observed morbidity rate. While our case analysis did not reveal any clear indication of one particular technique being superior, the selection of methods should be based on several factors, and this algorithm could serve as a useful aid in that regard. A comprehensive and standardized clinical assessment of facial palsy, both before and after surgery, is crucial to establish a consensus and plan individualized therapy.

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.

Extradural contralateral S1 nerve root transfer for spastic lower limb paralysis

The current study aims to ascertain the anatomical feasibility of transferring the contralateral S1 ventral root (VR) to the ipsilateral L5 VR for treating unilateral spastic lower limb paralysis. Six formalin-fixed (three males and three females) cadavers were used. The VR of the contralateral S1 was transferred to the VR of the ipsilateral L5. The sural nerve was selected as a bridge between the donor and recipient nerve. The number of axons, the cross-sectional areas and the pertinent distances between the donor and recipient nerves were measured. The extradural S1 VR and L5 VR could be separated based on anatomical markers of the dorsal root ganglion. The gross distance between the S1 nerve root and L5 nerve root was 31.31 (± 3.23) mm in the six cadavers, while that on the diffusion tensor imaging was 47.51 (± 3.23) mm in 60 patients without spinal diseases, and both distances were seperately greater than that between the outlet of S1 from the spinal cord and the ganglion. The numbers of axons in the S1 VRs and L5 VRs were 13414.20 (± 2890.30) and 10613.20 (± 2135.58), respectively. The cross-sectional areas of the S1 VR and L5 VR were 1.68 (± 0.26) mm 2 and 1.08 (± 0.26) mm 2, respectively. In conclusion, transfer of the contralateral S1 VR to the ipsilateral L5 VR may be an anatomically feasible treatment option for unilateral spastic lower limb paralysis.

Feasibility of an endoscope-dominated side-to-end hypoglossal-facial anastomosis: an anatomical study

Objective

A surgical simulation of an endoscope-dominated side-to-end hypoglossal-facial anastomosis was performed to evaluate the feasibility.

Methods

Eight anatomical cadaver heads (16 sides) were recruited. The steps in conventional procedures were abbreviated or omitted. A facial nerve was first harvested near its external genu and was used for a side-to-end hypoglossal-facial anastomosis. The stump of the used facial nerve was truncated and recycled immediately caudal to the facial recess in another anastomosis and then recycled again at the stylomastoid foramen. As a recycled stump becomes too short to ensure a side-to-end anastomosis, the hypoglossal nerve was transected in situ, and an endoscopic end-to-end hypoglossal-facial anastomosis was attempted. Surgical simulation and quantitative measurement methods were used to analyze the anastomosis effects of different harvested sites of the facial nerve.

Results

Several steps in the conventional procedures provide little benefit in endoscopic surgery. A facial nerve stump recycled at the stylomastoid foramen is too short to ensure a tensionless side-to-end anastomosis. An endoscopic end-to-end hypoglossal-facial anastomosis was feasible, although it required more time than the classical microsurgical anastomosis. The greater agility of an endoscope enables the conventional surgical steps to be overlapped or interweaved into the procedure.

Conclusions

The multiple surgical fields and ability to manipulate the viewpoint provided by an endoscope have brought about breakthroughs in classical surgical paradigms. In addition, it is best to choose the sites of the facial nerve harvested near the external genu. If unavailable, an alternative section site could be selected immediately caudal to the facial recess, but cannot be distal to the stylomastoid foramen. The length of the stump should be individualized and preferably optimized with a nerve stimulator.

Modified hypoglossal-facial nerve anastomosis for peripheral-type facial palsy caused by pontine infarction: A case report and literature review

Background

Peripheral-type facial palsy could be caused by a lesion in the tegmentum of the pons, such as infarction, with a rare occurrence. We herein described a case of unilateral peripheral-type facial palsy induced by dorsolateral pontine infarction and treated this patient using modified hypoglossal-facial nerve anastomosis.

Case presentation

A 60-year-old female presented with dizziness, hearing drop, diplopia, and peripheral-type facial palsy. Brain Magnetic Resonance Imaging showed a dorsolateral pontine infarction on the right side which exactly refers to the location of the ipsilateral facial nucleus or facial nerve fascicles at the pons. Subsequent electrophysiological examinations confirmed poor facial nerve function of this patient and modified hypoglossal-facial nerve anastomosis was then performed.

Conclusions

This case reminded medical practitioners not to ignore the possibility of involvement of a central cause in peripheral-type facial palsy patients. In addition, modified hypoglossal-facial nerve anastomosis served as a useful skill improvement that may help reduce hemiglossal dysfunction while restoring facial muscle function.

The Posterior Belly of Digastric Muscle as the Landmark in Facial Nerve Anastomosis Surgery: Anatomical Study and Case Illustration

OBJECTIVE

To establish a new method for fast exposure of the facial nerve and hypoglossal nerve during facial nerve anastomosis surgery.

METHODS

Dissection of 12 formalin-fixed cadaveric specimens was performed to explore the positional relationship between the posterior belly of digastric muscle (PBD) and the facial nerve and hypoglossal nerve. We retrospectively reviewed patients who underwent facial nerve reconstruction surgery between 2015 and 2020 at Xuanwu Hospital, Capital Medical University, and the optimized surgical strategy based on the PBD was proposed.

RESULTS

The trunk of the hypoglossal nerve runs across the external carotid artery after giving off the descendens hypoglossi located within the 1-cm scope deep to the junction of the tendon and belly of the PBD. The mean depth difference between the hypoglossal nerve and the junction of the tendon and belly of the PBD was 5.48 ± 2.24 mm (range, 1.88-9.27 mm). The stylomastoid foramen segment of the facial nerve was revealed after the parotid gland was dissected within the angle between the anterior margin of the mastoid tip and the inferior margin of the cartilage of the external acoustic meatus.

CONCLUSIONS

The facial nerve and hypoglossal nerve can be rapidly identified using the PBD as an anatomical landmark. The end-to-end facial-descendens hypoglossi anastomosis is a reliable facial nerve reconstruction method for patients whose facial nerve was damaged during operation.

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.

Muscle-Nerve-Nerve Grafting Improves Facial Reanimation in Rats Following Facial Nerve Injury

Nerve injury resulting in muscle paralysis from trauma or surgery is a major medical problem. Repair of such injuries with existing nerve grafting and reconstructive techniques often results in less than optimal outcomes. After previously demonstrating significant return of function using muscle-nerve-muscle (MNM) grafting in a rat facial nerve model, this study compares a variant of the technique, muscle-nerve-nerve (MNN) neurotization to MNM and interposition (IP) nerve grafting. Thirty male rats were randomized into four groups (1) control with no intervention, (2) repair with IP grafts, (3) MNM grafts and (4) MNN grafts. All groups had the buccal and marginal mandibular branches of the right facial nerve resected. Return of vibrissae movement, orientation, and snout symmetry was measured over 16 weeks. Functional recovery and muscle atrophy were assessed and quantified. All interventions resulted in significant improvement in vibrissae movement and orientation as compared to the control group (p < 0.05). The MNM and MNN groups had significantly less time to forward vibrissae movement as compared to controls (p < 0.05), and a large number of animals in the MNN group had coordinated vibrissae movement at 16 weeks. MNN and IP grafts retained significantly more muscle mass as compared to control (p < 0.05). Thus, MNN grafting is a promising adjuvant or alternative technique for reanimation for patients with unilateral peripheral nerve injury who are not candidates for primary neurorrhaphy.

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.

End-to-Trunk Masseteric to Facial Nerve Transfer With Selective Neurectomy for Facial Reanimation

OBJECTIVE

To examine functional outcomes following end-to-trunk masseteric to facial nerve transfer in patients with chronic flaccid facial paralysis.

DESIGN

Retrospective chart review.

SETTING

Tertiary-care private practice setting.

PARTICIPANTS

Patients with complete unilateral facial paralysis of less than 24 months duration.

INTERVENTIONS

Direct end-to-trunk masseteric to facial nerve anastomosis.

OUTCOME MEASURES

Outcome measures included time to first movement, development of synkinesis, and an objective assessment of the resting tone and dynamic movement that was achieved.

RESULTS

Patient age at the time of transfer ranged from 6 to 61. Follow-up ranged from 12 to 24 months. No patients had any perioperative complications. No patient experienced significant mass movement or synkinetic facial movement with chewing. No patient had worsened chewing or swallowing. Patients have not yet recovered significant resting tone. All patients achieved smile activity when biting down with a median (interquartile range) oral commissure excursion of 7.57 mm (5.19-9.94 mm), starting 3 to 5 months after transfer.

CONCLUSIONS

End-to-trunk masseteric to facial nerve transfer is a safe and effective procedure. Patients had rapid reinnervation with good excursion and achieved a natural appearing smile. The rehabilitated smile appears better than that achieved with hypoglossal-facial nerve transfer. The procedure can be performed coincident with cross-facial nerve grafting, and in some cases may produce dynamic facial movement that obviates the need for free muscle transfer.

The Masseteric-Facial Anastomosis With Intratemporal Translocation of the Facial Nerve: Step-by-Step Technique and Results

BACKGROUND

In the absence of a viable proximal nerve stump, damaged after surgical procedures around the skull base, numerous techniques for facial reanimation have been developed over time, aiming to restore baseline symmetry and active mimicry.

OBJECTIVE

To report experience using the masseteric nerve as a direct transfer to the facial nerve rerouted after intratemporal translocation. This paper illustrates the main steps of the technique and the quality of results.

METHODS

Eleven patients were treated with a masseteric direct transfer to the facial nerve. Its extratemporal rerouting toward the zygoma allowed tension-free coaptation between donor and recipient nerves.

RESULTS

Of the 11 patients, 8 had a good to excellent recovery, showing different patterns of time and scores, according to age, surgical timing, and masseteric nerve function quality. The return of activity in the frontalis muscle, never obtained after reinnervation via the hypoglossal nerve, is of particular interest. The quality of the smile can be improved with re-education and practice but remains under volitional control. A true emotional response is still lacking.

CONCLUSION

The masseteric nerve is an excellent alternative to the hypoglossal nerve and can reinnervate the whole territory of the facial nerve rerouted after intratemporal translocation. The overall results are remarkable, but the low quality of the trigeminal nerve, eventually affected by the first surgery, may be an important limitation. Even if the patients appear more at ease in re-education than with other techniques, a fully natural facial expression remains impossible to obtain.

Reinnervation with Selective Nerve Grafting from Multiple Donor Nerves

Nerve substitution is an important tool in facial reanimation. The goal is to reinnervate the distal facial nerve and musculature using an alternative cranial nerve in order to achieve facial movement, symmetry, and tone. Multiple donor nerves have been used for nerve transfer procedures, the most common being hypoglossal, masseteric, and cross-facial nerve graft. Each donor nerve has its advantages and disadvantages. Multiinnervation uses the use of multiple donor nerves in order to leverage the benefits while balancing the pitfalls of each nerve. The nerve transfer depends on the type of nerve injury, time since injury, and patient factors.

Microanatomic analyses of extratemporal facial nerve and its branches, hypoglossal nerve, sural nerve, and great auricular nerve

OBJECTIVE

To investigate microanatomic organizations of the extratemporal facial nerve and its branches, hypoglossal nerve, sural nerve, and great auricular nerve.

METHODS

Nerve samples were dissected in 12 postmortem autopsies, and histomorphometric analyses were conducted.

RESULTS

There was no significant difference between the right and left sides of the nerve samples for the nerve area, fascicle area, number of fascicles and average number of axons. The lowest mean fascicle number was found in the hypoglossal nerve (4.9 ± 1.4) while the highest was in great auricular nerve (11.4 ± 6.8). The highest nerve area (3,182,788 ± 838,430 μm²), fascicle area (1,573,181 ± 457,331 μm²) and axon number (14,772 ± 4402) were in hypoglossal nerve (p < 0.05). The number of axons per unit nerve area was higher in the facial nerve, truncus temporofacialis, truncus cervicofacialis and hypoglossal nerve, which are motor nerves, compared to the sural nerve and great auricular nerve, which are sensory nerves (p < 0.05). The number of axons per unit fascicle area was also higher in motor nerves than in sensory nerves (p < 0.05).

CONCLUSION

In the present study, it was observed that each nerve contained a different number of fascicles and these fascicles were different both in size and in the number of axons they contained. All these variables could be the reason why the desired outcomes cannot always be achieved in nerve reconstruction.

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.

Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives

Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury.

Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base.

Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones.

Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.

Hemihypoglossal-facial nerve anastomosis: results and electromyographic characterization

INTRODUCTION

The facial nerve surgery belongs to the basic procedures during lateral skull base approaches. Its damage has serious medical and psychological consequences, and therefore mastery of reconstruction and correction techniques should belong to the repertoire of skull base surgeons. The goal of this study was to demonstrate usefulness of electromyographic follow-up in facial nerve reconstruction.

MATERIAL AND METHODS

A total of 16 patients underwent hemihypoglossal-facial anastomosis between 2005 and 2017. Most of the primary lesions came from vestibular schwannoma surgery. All patients were examined with electromyography and scored according to the House-Brackmann and IOWA grading scales. Function of the tongue has been evaluated.

RESULTS

Ten patients achieved definitive House-Brackmann grade 3 score (62.5%). We did not observe any association with the patient's age, previous irradiation and the etiology of the damage. Electromyography showed pathological spontaneous activity after the first surgery. Incipient regeneration potentials were detected in 4-17 months (average 7.6) and reached maximum in 6.5-18 months (average 16). Electromyographic assessment of the effect of tongue movement showed better mimic voluntary activity by swallowing or by moving the tongue up. There was no relationship between the start of activity and the interval to achieving maximal activity.

CONCLUSION

Hemihypoglossal-facial nerve anastomosis is a safe procedure and it is an optimal solution for cases lacking a proximal stump or in the case of reconstruction in the second stage. Electromyography can predict initial reinnervation activity after reconstructive procedures. During subsequent follow-up it can help to discover insufficiently recovering patients, however clinical characteristics are crucial.

Tissue-engineered nerve guides with mesenchymal stem cells in the facial nerve regeneration

Nerve guides with mesenchymal stem cells have been investigated in the rat facial nerve defect model to promote peripheral nerve regeneration and shorten recovery time to improve patients' quality of life. A 7-mm facial nerve gap experimental rat model is frequently employed in facial nerve regeneration studies. Facial nerve regeneration with nerve guides is evaluated by (1) assessing myelinated fiber counts using toluidine blue staining, (2) immunohistological analysis, (3) determining the g-ratio (axon diameter/total outer diameter) of regenerated nerve on transmission electron microscopic images, (4) retrograde nerve tracing in the facial nucleus, (5) electrophysiological evaluations using compound muscle action potential, and (6) functional evaluations using rat facial palsy scores. Dental pulp and adipose-derived stem cells, easily harvested using a minimally invasive procedure, possess characteristics of mesenchymal tissue lineages and can differentiate into Schwann-like cells. Cultured dental pulp-derived cells can produce neurotrophic factors, including nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor. These neurotrophic factors promote peripheral nerve regeneration and afford protection against facial motor neuron death. Moreover, artificial nerve guides can maneuver axonal regrowth, and dental pulp-derived cells and adipose-derived Schwann cells may supply neurotrophic factors, promoting axonal regeneration. In the present review, the authors discuss facial nerve regeneration using nerve guides with mesenchymal stem cells.

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.

Modern Management of Facial Nerve Disorders

Facial paralysis is a devastating condition, encompassing a spectrum of disorders, with resultant psychosocial, functional, and aesthetic sequelae. With this in mind, an individualized treatment approach based on the cause, pattern, and duration of palsy is necessary. Treatment options include pharmacologic agents, corneal protective interventions, physical therapy, and surgical procedures. The use of steroids and antivirals in the setting of idiopathic facial paralysis or virus-associated facial paralysis is well supported. Despite the diversity of surgical interventions described, there is a lack of consensus regarding optimal treatment. This article provides an overview of the current management of facial paralysis. Medical, surgical, and physical treatment options are discussed with a review of the relevant literature.

Split hypoglossal facial anastomosis for facial nerve palsy due to skull base fractures: A case report

Introduction

Traumatic brain injury (TBI) is the most prevalent causes of morbidity and mortality worldwide. The biomechanics of primary TBI involve a direct impact, practically extended to the base of the skull, and most of the skull base fractures (SBF) are identified in anterior and medial cranial fossa. Furthermore, those predicted in the medial area are related to fissures from temporal bones.

Presentation of case

We report two cases of right facial nerve palsy initiated by SBF's, which were diagnosed and treated at our institution. The 3D CT evaluation in our first case showed a longitudinal fracture of the right petrosal bone, which was longitudinal and transverse for the second case. Two cases of facial nerve palsy were managed with split hypoglossal facial anastomosis to restore functional reanimation. All patients were adequately achieved after the procedure, and the hypoglossal nerve function was preserved.

Conclusion

Split hypoglossal facial anastomosis technique was used to treat patients with facial nerve paralysis resulting from SBF's. This was to achieve good recovery outcome, in terms of facial reanimation and preservation of tongue function.

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A skull base fracture (SBF) is about 4% of all cases Traumatic brain injury (TBI).

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SBF which frequently occurs in the petrous part of the temporal bone, is implicated in facial nerve palsy.

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Split hypoglossal facial anastomosis technique showed good recovery of facial reanimation with HB scale assessment.

Pediatric facial reanimation: An algorithmic approach and systematic review

Facial palsy has a broad clinical presentation and the effects on psychosocial interaction and facial functions can be devastating. Pediatric facial palsy, in particular, introduces unique familial and technical considerations as anatomy, future growth potential, and patient participation influence treatment planning. Though some etiologies of pediatric facial palsy are self-limiting, congenital and long-standing facial palsies pose difficult challenges that require a combination of surgical, adjunctive, and rehabilitative techniques to achieve facial reanimation. Given the spectrum of ages and symptom severity, as well as the various surgical options available for facial palsy, a tailored approach needs to be developed for each child to restore facial balance and function. Here, we review the etiologies, workup, and treatment of pediatric facial palsy and present our novel algorithmic approach to treatment.

Using the Post-Descendens Hypoglossal Nerve in Hypoglossal-Facial Anastomosis: An Anatomic and Histologic Feasibility Study

BACKGROUND

Hypoglossal-facial anastomosis (HFA) is a popular facial reanimation technique. Mobilizing the intratemporal segment of the facial nerve and using the post-descendens hypoglossal nerve (ie, the segment distal to the take-off of descendens hypoglossi) have been proposed to improve results. However, no anatomic study has verified the feasibility of this technique.

OBJECTIVE

To assess the anatomic feasibility of HFA and the structural compatibility between the 2 nerves when the intratemporal facial and post-descendens hypoglossal nerves are used.

METHODS

The facial and hypoglossal nerves were exposed bilaterally in 10 sides of 5 cadaveric heads. The feasibility of a side-to-end (ie, partial end-to-end) HFA with partial sectioning of the post-descendens hypoglossal nerve and the mobilized intratemporal facial nerve was assessed. The axonal count and cross-sectional area of the facial and hypoglossal nerves at the point of anastomosis were assessed.

RESULTS

The HFA was feasible in all specimens with a mean (standard deviation) 9.3 (5.5) mm of extra length on the facial nerve. The axonal counts and cross-sectional areas of the hypoglossal and facial nerves matched well. Considering the reduction in the facial nerve cross-sectional area after paralysis, the post-descendens hypoglossal nerve can provide adequate axonal count and area to accommodate the facial nerve stump.

CONCLUSION

Using the post-descendens hypoglossal nerve for side-to-end anastomosis with the mobilized intratemporal facial nerve is anatomically feasible and provides adequate axonal count for facial reanimation. When compared with use of the pre-descendens hypoglossal nerve, this technique preserves C1 fibers and has a potential to reduce glottic complications.

Functional Outcome and Quality of Life After Hypoglossal-Facial Jump Nerve Suture

Background: To evaluate the face-specific quality of life after hypoglossal-facial jump nerve suture for patients with long-term facial paralysis.

Methods: A single-center retrospective cohort study was performed. Forty-one adults (46% women; median age: 55 years) received a hypoglossal-facial jump nerve suture. Sunnybrook and eFACE grading was performed before surgery and at a median time of 42 months after surgery. The Facial Clinimetric Evaluation (FaCE) survey and the Facial Disability Index (FDI) were used to quantify face-specific quality of life after surgery.

Results: Hypoglossal-facial jump nerve suture was successful in all cases without tongue dysfunction. After surgery, the median FaCE Total score was 60 and the median FDI Total score was 76.3. Most Sunnybrook and eFACE grading subscores improved significantly after surgery. Younger age was the only consistent independent predictor for better FaCE outcome. Additional upper eyelid weight loading further improved the FaCE Eye comfort subscore. Sunnybrook grading showed a better correlation to FaCE assessment than the eFACE. Neither Sunnybrook nor eFACE grading correlated to the FDI assessment.

Conclusion: The hypoglossal-facial jump nerve suture is a good option for nerve transfer to reanimate the facial muscles to improve facial motor function and face-specific quality of life.

Side-to-End Hypoglossal-Facial Neurorrhaphy for Treatment of Complete and Irreversible Facial Paralysis after Vestibular Schwannoma Removal by Means of a Retrosigmoid Approach: A Clinical and Anatomic Study

BACKGROUND

Facial paralysis secondary to a complete and irreversible anatomic or functional lesion of the facial nerve (FN) causes severe functional and psychological disorders for the patient. A large number of surgical techniques have therefore been developed for FN repair. Our objective was to propose a surgical FN reanimation protocol for patients with irreversible anatomic or functional postsurgical injury of the FN in the cerebellopontine angle after vestibular schwannoma resection.

METHODS

The clinical study included a total of 16 patients undergoing side-to-end hypoglossal-facial neurorrhaphy (SEHFN) since 2010, in which the FN injury was always secondary to vestibular schwannoma surgery in the cerebellopontine angle using a retrosigmoid approach. All patients had complete clinical facial paralysis at the time of the SEHFN. The anatomic study was conducted using 3 heads and necks (6 SEHFN).

RESULTS

Twelve months after surgery, FN function assessment with the House and Brackmann scale showed 2 patients with grade II, 13 patients with grade III, and only 1 patient with grade IV, and after 2 years, 4 patients had grade II, 11 patients had grade III, and 1 patient had grade IV. The average length of the anastomotic translocation portion of the FN in the anatomic study was 34.76 mm.

CONCLUSIONS

Side-to-end epineural suture of the FN, mobilizing its mastoid segment on the hypoglossal nerve with partial section of the dorsal aspect of the hypoglossal nerve, is a safe anatomic surgical technique for FN reanimation with outstanding clinical results.

Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery

BACKGROUND

The facial nerve and its branches are at risk of injury during dermatologic surgery. Few publications in the dermatologic literature discuss facial nerve injury and management.

OBJECTIVE

To review facial nerve injury and management, including static and dynamic repair techniques, and to review outcomes in facial nerve reconstruction.

METHODS

Two detailed literature reviews were performed using PubMed. First, articles reporting facial nerve injury and/or management in the dermatologic literature were identified. In addition, articles pertaining to outcomes in facial nerve reconstruction with a minimum of 20 patients were included.

RESULTS

Fifty-three articles reporting outcomes in facial nerve reconstruction were identified and consist of retrospective reviews and case series. Most patients achieve improvement in facial symmetry and movement with nerve repair.

CONCLUSION

Timing of facial nerve repair is an important consideration in management of facial nerve injury, with earlier repairs achieving better outcomes. Facial nerve repair does not result in normal facial movement, and improvements may require a year or more to be realized. Many options exist for facial nerve reconstruction, and patients with long-standing facial nerve injuries may still benefit from treatment.

[Update on diagnostics and microsurgical treatment of vestibular schwannoma]

Vestibular schwannomas are primary benign tumors of the cerebellopontine angle originating either from the superior or the inferior vestibular nerve. Hearing deterioration is the leading symptom, which is why the widespread name for this tumor is acoustic neuroma. Due to the widespread availability of magnetic resonance imaging (MRI), the diagnosis of vestibular schwannoma is frequently made in an early stage of the disease. In these cases a wait and scan policy is recommended. If the tumor grows, the therapeutic options are stereotactic radiotherapy or microsurgical tumor operation. Young patient age, functional hearing ability, persistent dizziness, cystic tumor consistence and large space-occupying tumor size are in favor of surgery via the retrosigmoid, transmeatal approach. In experienced hands excellent results in terms of functional preservation of the facial nerve and the cochlear nerve and radical tumor resection can be obtained.

The Feasibility of Using the Posterior Auricular Branch of the Facial Nerve as a Donor for Facial Nerve Reanimation Procedures: A Cadaveric Study

PURPOSE

Facial nerve paralysis can result in critical complications, including those to the visual, respiratory, and digestive systems. The facial nerve has been reanimated using various nerves, but the posterior auricular nerve (PAN) branching off the facial nerve has not been explored for this purpose.

MATERIALS AND METHODS

Ten sides from 6 fresh-frozen adult cadavers were used for dissection of the PAN to explore its potential as a donor for facial nerve reanimation. The facial nerve trunk (FNT) and PAN were consistently and readily identified by deep dissection using the tragal cartilage and tragal pointer as landmarks. The PAN was transected at the point of insertion of its innervated muscles. Its length and diameter were measured, and it was transposed anteriorly to the FNT and its 2 major extracranial divisions.

RESULTS

The PAN was observed on all sides. Its available length was 27.11 ± 5.02 mm and its mean diameter was 0.85 ± 0.20 mm. In all specimens, the PAN readily reached the FNT and its 2 major divisions without tension.

CONCLUSION

No previous study has explored the use of the PAN as a donor for facial nerve reanimation. Based on the present cadaveric study, surgeons might consider it for this purpose.

Neurorrhaphy for Facial Reanimation with Interpositional Graft: Outcome in 23 Patients and the Impact of Timing on the Outcome

OBJECTIVE

Neurorrhaphy with interpositional graft is a practical technique to achieve facial reanimation when the continuity of the facial nerve is interrupted and a large gap between the proximal and distal stump exists. The aim of this study was to report long-term outcomes of neurorrhaphy for facial reanimation with interpositional graft. The roles of some variable factors in the outcome of neurorrhaphy with interpositional graft were also evaluated and compared.

METHODS

A retrospective case series from a single tertiary referral center comprised 23 patients with facial nerve interruptions who underwent neurorrhaphy with interpositional graft using either end-to-end anastomosis or end-to-side hypoglossal-facial technique. Preoperative data (age, sex, primary lesion, interval from paralysis to surgery, facial nerve function), intraoperative data (surgical approach, graft and type of neurorrhaphy), and postoperative data (facial nerve function) were collected and analyzed.

RESULTS

Mean follow-up time was 26.6 ± 11.9 months. Patients who underwent neurorrhaphy for facial reanimation within 1 year after onset of facial paralysis were more likely to achieve House-Brackmann grade ≤3 compared with patients who underwent neurorrhaphy >1 year after onset of facial paralysis (odds ratio = 23.85, P = 0.04). No other factors were associated with improved outcomes.

CONCLUSIONS

Early neurorrhaphy with interpositional graft (≤1 year) for facial reanimation resulted in better final facial nerve function outcomes compared with a delayed procedure.

Surgical anatomy of ovine facial and hypoglossal nerves for facial nerve reconstruction and regeneration research: An experimental study in sheep

BACKGROUND

The lack of a clinically relevant animal model for facial nerve research is a challenge. The goal of this study was to investigate the anatomy of the ovine facial and hypoglossal nerves to establish a clinically relevant facial nerve research model.

MATERIALS AND METHODS

Six cadaver female Merino sheep (33.5 ± 3 kg, approximately 3 years old) and three anesthetized female Merino sheep (30 ± 3 kg, approximately 3 years old) were used. In cadaver sheep, a right side preauricular to submandibular incision was made. Dimensions of the face, neck, and length of facial nerve were measured. In anesthetized sheep, each facial nerve branch and hypoglossal nerve in the right side was stimulated. The number of myelinated fibers was analyzed histologically.

RESULTS

The facial nerve exited the stylomastoid foramen and divided into upper and lower branches. The lower branch then subdivided into buccal and marginal mandibular branches. The hypoglossal nerve was observed behind the digastric posterior belly. Stimulation revealed the temporal, zygomatic, buccal, marginal mandibular, and cervical branch innervated the forehead, orbicularis, upper lip and nasal, lower lip, and platysma, respectively. The number of myelinated fibers of the main trunk, upper, buccal, lower branch, and hypoglossal nerve was 11 350 ± 1851, 4766 ± 1000, 5107 ± 218, 3159 ± 450, and 7604 ± 636, respectively. The length of the main trunk was 9.2 ± 1.5 mm, and distance of the marginal mandibular branch to the facial artery was 94 ± 6.8 mm.

CONCLUSIONS

Due to the similarity in nerve anatomy and innervation, the ovine model can be used as a clinically relevant and suitable model for facial nerve research.

Axonal supercharged interpositional jump-graft with a hybrid artificial nerve conduit containing adipose-derived stem cells in facial nerve paresis rat model

PURPOSE

Interpositional jump-graft (IPJG) technique with the hypoglossal nerve for supercharging can be applied in a facial nerve paresis case. In IPJG, an autologous nerve is required, and the donor site morbidity is unavoidable. Biodegradable nerve conduits are made from polyglycolic acid (PGA) and used recently without donor site complications after providing autologous grafts. Hybrid artificial nerve conduits with adipose-derived stem cells (ASCs) also attract attention as a nerve-regeneration enhancing agent. This study examined the effect of hybrid artificial nerve conduit on IPJG.

MATERIALS AND METHODS

A total of 34 Lewis rats were used and divided into 4 groups by the bridge materials: autograft (n = 8), PGA nerve conduit (n = 8), hybrid PGA nerve conduit with ASCs (n = 8), and the nontreated control groups (n = 8). ASCs were collected from 2 rats and cultured. The animals were assessed physiologically and histopathologically at 13 weeks after surgery.

RESULTS

In compound muscle action potential, the amplitude of hybrid PGA group (3,222 ± 1,779 μV) was significantly higher than that of PGA group (1,961 ± 445 μV, P < .05), and no significant difference between hybrid PGA and autograft group. All treated groups showed a myelinated nerve regeneration with double innervation in hypoglossal and facial nerve nuclei for vibrissal muscle.

CONCLUSION

This study showed the effectiveness of IPJG with a hybrid PGA conduit especially in physiological examination.

The surgical management of bilateral facial paralysis: case report

Background

Unilateral total facial palsy is a debilitating condition that can affect an individual's physical, social and emotional wellbeing. When this occurs bilaterally, the severity of impact is extreme, with significant cosmetic disfigurement and functional morbidity. A variety of facial reanimation techniques have been used for unilateral facial weakness of varying House–Brackmann grades, and these are also applicable in bilateral cases. In bilateral cases, it is difficult to gauge successful improvement in comparison to the contralateral side, which also is afflicted.

Case report

This paper presents our experience with a bilateral facial paralysis patient who had a complex otological history. The patient, who presented with bilateral debilitating grade VI facial palsy, achieved a good result from bilateral facial reanimation with sequential hypoglossal–facial anastomosis. This is considered a reasonable option in cases of bilateral facial paralysis.

Hemihypoglossal-Facial Nerve Anastomosis for Facial Nerve Reanimation: Case Series and Technical Note

BACKGROUND

Hypoglossal nerve injury may result in swallowing and speech problems. To reduce this morbidity and allow the performance of the hypoglossal-facial nerve anastomosis bilaterally, a technique that includes partial splitting of the hypoglossal nerve and skeletonization of the facial nerve within the mastoid process has been applied. The aim of this study is to present clinical results regarding the facial and hypoglossal nerves after the procedure.

METHODS

Prospectively collected data from 56 consecutive patients who underwent hemihypoglossal-facial nerve anastomosis (HHFA) were analyzed. The outcome was correlated with epidemiologic data, initial disease, the presence of neurofibromatosis type 2, previous radiosurgery, and the time between nerve injury and reconstructive surgery.

RESULTS

Forty-eight (84%) patients achieved satisfactory outcomes; 8 of them (14%) showed some improvement, and in 1 patient (2%) there was no improvement during long-term observation. The result at follow-up was not related to the time interval between the 2 procedures. However, recovery times for facial tonicity were statistically significantly longer if the procedure was performed after 12 months (P = 0.044). There was no statistically significant association between patient age (P = 0.96) or sex (P = 0.13) and facial nerve function. HHFA resulted in no or minimal tongue atrophy without deviation in 53 patients (93%), and the remainder had mild hemiatrophy with tongue deviation <30 degrees.

CONCLUSIONS

HHFA is an effective technique for facial nerve reanimation with acceptable morbidity related to tongue function. Patients with a longer duration of facial palsy still have a good chance for restoration of facial movement but require longer recovery periods.

[Surgical indications and complications management in vestibular schwannoma]

BACKGROUND

Recent surgical treatment concepts for patients with vestibular schwannoma (VS) require an interdisciplinary approach as well as recognition and mastering of complications.

OBJECTIVE

This paper provides an overview of indications, as well as possible options for function preservation and management of complications in the surgical resection of these tumors.

METHODS

Up-to-date treatment concepts and surgical indications were differentiated according to size and extent of tumors. The frequency of important complications was extracted from the literature. Technical options to avoid and correct complications were compiled from personal experience and review of the literature.

RESULTS

Complications unrelated to cranial nerves are not infrequent, particularly in older patients. Small and medium-sized tumors that do not reach the fundus and cochlear fossa can be completely removed with good chances of hearing preservation. As long as these tumors do not grow, patients benefit from observation. Large tumors are overrepresented in surgical series compared to their prevalence. Postoperative facial nerve function correlates to tumor volume. Hearing preservation in these tumors is rare. Intraoperative electrophysiological techniques are valuable for attempted preservation of cranial nerve function. Persistent facial palsies can be remedied by dynamic and static interventions for facial rehabilitation.

CONCLUSION

Mortality and morbidity associated with surgical treatment of VS are very acceptable. Surgical concepts should be custom-tailored to the individual patient in order to ensure high quality of life.

End-to-end and end-to-side neurorrhaphy between thick donor nerves and thin recipient nerves: an axon regeneration study in a rat model

During nerve reconstruction, nerves of different thicknesses are often sutured together using end-to-side neurorrhaphy and end-to-end neurorrhaphy techniques. In this study, the effect of the type of neurorrhaphy on the number and diameter of regenerated axon fibers was studied in a rat facial nerve repair model. An inflow-type end-to-side and end-to-end neurorrhaphy model with nerve stumps of different thicknesses (2:1 diameter ratio) was created in the facial nerve of 14 adult male Sprague-Dawley rats. After 6 and 12 weeks, nerve regeneration was evaluated in the rats using the following outcomes: total number of myelinated axons, average minor axis diameter of the myelinated axons in the central and peripheral sections, and axon regeneration rate. End-to-end neurorrhaphy resulted in a significantly greater number of regenerated myelinated axons and rate of regeneration after 6 weeks than end-to-side neurorrhaphy; however, no such differences were observed at 12 weeks. While the regenerated axons were thicker at 12 weeks than at 6 weeks, no significant differences in axon fiber thickness were detected between end-to-end and end-to-side neurorrhaphy. Thus, end-to-end neurorrhaphy resulted in greater numbers of regenerated axons and increased axon regeneration rate during the early postoperative period. As rapid reinnervation is one of the most important factors influencing the restoration of target muscle function, we conclude that end-to-end neurorrhaphy is desirable when suturing thick nerves to thin nerves.

Diagnostics and therapy of vestibular schwannomas - an interdisciplinary challenge

Vestibular schwannomas (VS) expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100,000 vestibular schwannoma represent 6-7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function. Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options - watchful waiting, microsurgery and stereotactic radiation - should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several articles and reviews have been published on the topic of vestibular schwannoma. On the occasion of the 88^th annual meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck surgery a special volume of the journal "HNO" will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases that outline examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and comorbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient's preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process. We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient's quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient's dependence on social welfare. Pathognomonic bilateral vestibular schwannomas that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions. Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlear and auditory brainstem implants.