Facial nerve sacrifice in lateral approaches to the skull base: Simultaneous reconstruction by graft interposition.

PURPOSE: To evaluate the outcome of facial nerve (FN) cable graft interposition in lateral skull base surgery. MATERIALS AND METHODS: A group of 16 patients who underwent FN graft interposition procedure was retrospectively considered. Postoperative FN function was evaluated using the House-Brackmann (HB) grading system, the Sunnybrook Facial Grading System (SFGS), the Facial Disability Index (FDI) and the Oral Functioning Scale (OFS) questionnaires. RESULTS: 56.2% of patients had a good postoperative FN outcome (HB grade II-III). Postoperative electromyography (EMG) showed re-innervation potentials in 60% of patients; median age of these patients was significantly lower compared to who did not manifest re-innervation (p = 0.039). CONCLUSION: FN primary reconstruction remains the advisable rehabilitative option when the nerve is interrupted during lateral skull base surgeries, allowing to satisfactory postoperative results in more than half of patients. EMG confirmed the restoring of nerve conduction and it was more frequent in younger patients. The SFGS, the FDI and the OFS are important tools especially in the setting of a rehabilitation program.

Anatomical Feasibility Study of the Digastric Branch of the Facial Nerve: A Potential Donor for Facial Nerve Reanimation.

PURPOSE: The digastric branch is the second branch of the facial nerve after emerging from the stylomastoid foramen. To the best of our knowledge, few detailed anatomic studies of the digastric branch have been performed. Moreover, the use of the digastric branch for facial nerve reanimation has not been explored. MATERIALS AND METHODS: Nine sides of 5 fresh frozen cadavers were dissected for anatomic observation of the digastric branch and exploration of the feasibility of the digastric branch as a donor for facial nerve reanimation. The facial nerve trunk (FNT) and digastric branch were readily found by dissection using the tragal cartilage and tragal pointer as landmarks. The length and diameter of the digastric branch were measured, and the digastric branch was repositioned anterior to the FNT and the 2 major extracranial divisions of the FNT. RESULTS: On all sides, the digastric branch existed as a single branch and innervated only the posterior belly of the digastric muscle. The available length of the digastric branch was 13.28 ± 2.47 mm (range, 8.87 to 16.38 mm), and the mean diameter was 0.98 ± 0.31 mm (range, 0.64 to 1.64 mm). The digastric branch reached the FNT and its 2 major divisions without tension. CONCLUSIONS: The results of the present study have clarified the anatomic findings of the digastric branch in detail and the feasibility of using the digastric branch as a potential donor for facial nerve reanimation. The surgeon might consider the use of the digastric branch as a feasible donor for facial nerve reanimation based on the findings from our cadaveric study.

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.

Comprehensive approach to reestablishing form and function after radical parotidectomy.

INTRODUCTION: The reconstructive goals following radical parotidectomy include restoration of symmetry, reanimation of the face, and reestablishment of oral competence. We present our experience utilizing the anterolateral thigh (ALT) free flap, orthodromic temporalis tendon transfer (OTTT), and facial nerve cable grafting to reestablish form and function. MATERIAL AND METHODS: From 2010 to 2016, 17 patients underwent radical parotidectomy followed by immediate reconstruction. An ALT was harvested to accommodate the volume and skin defect. Additional fascia lata and motor nerve to vastus lateralis (MNVL) were obtained. Anastomosis of the ALT to recipient vessels was performed, most commonly using the facial artery and internal jugular vein. OTTT was performed by securing the medial tendon of the temporalis to orbicularis oris through a nasolabial incision. Fascia lata was tunneled through the lower lip, then secured laterally to the temporalis tendon. The MNVL was cable grafted from either the proximal facial nerve or masseteric nerve to the distal facial nerve branches. ALT fascia was suspended to the superficial muscular aponeurotic system. RESULTS: Average follow up was 19 months. Only one patient failed to achieve symmetry attributed to dehiscence of OTTT. All patients achieved oral competence and dynamic smile with OTTT activation. Facial nerve recovery was seen in 8 patients. 5 reached a House Brackman Score of 3. Two donor site seromas and two wound infections occurred. CONCLUSION: Simultaneous ALT, OTTT, and facial nerve cable grafting provides early reestablishment of facial symmetry, facial reanimation, and oral competence with minimal morbidity.

Comparison of Functional Results After Cross-Face Nerve Graft-, Spinal Accessory Nerve-, and Masseter Nerve-Innervated Gracilis for Facial Paralysis Reconstruction: The Chang Gung Experience.

BACKGROUND: Using functioning free muscle transplantation (FFMT) for facial paralysis and postparalysis facial synkinesis reconstruction is our preferred technique. Gracilis was the first choice of muscle. Three motor neurotizers: cross-face nerve graft (CFNG), spinal accessory nerve (XI) and masseter nerve (V3) have been used as neurotizers for different indications. METHODS: A total of 362 cases of facial reanimation with FFMT were performed between 1986 and 2015. Of these, 350 patients with 361 FFMT were enrolled: 272 (78%) patients were treated by CFNG-gracilis, 56 (15%) by XI-gracilis, and 22 (6%) by V3-gracilis. Smile excursion score, cortical adaptation stage with tickle test for spontaneous smile, facial synkinesis, satisfaction score by questionnaire, and functional facial grading were used for outcome assessment. RESULTS: The CFNG-gracilis in a 2-stage procedure achieved most natural and spontaneous smile when longer observation (≥2 years) was followed. The single-stage procedure using the XI-gracilis has proven a good alternative. V3-gracilis provided high smile excursion score in the shortest rehabilitation period, but never obtained spontaneous smile. CONCLUSIONS: The CFNG-gracilis remains our first choice for facial paralysis reconstruction which can achieve natural and spontaneous smile. XI- or V3-gracilis can be selected as a save procedure when CFNG-gracilis fails. The V3-gracilis is indicated in some specific conditions, such as bilateral Möbius syndrome, older patients (age, >70 years), or patients with malignant disease.

End-to-side neurotization with different donor nerves for treating brachial plexus injury: an experimental study in a rat model.

INTRODUCTION: End-to-side neurotization is currently used to treat brachial plexus injury, but it is not clear which donor nerve yields the best outcome. We performed experiments to determine the optimal donor nerve. METHODS: A total of 66 male Sprague-Dawley rats were assigned to 1 of 3 groups. Group A was the control group. In Group B, the phrenic nerve was used as the donor, while the ipsilateral C7 nerve root served as the donor in Group C. The epineurial window was used in end-to-side neurorrhaphy. Behavioral observations, histology, electrophysiology, and fluorescence retrotracing were performed postoperatively. RESULTS: Fluorescence retrotracing confirmed nerve regeneration in both Groups B and C upon end-to-side neurotization. The outcome of Group B was superior to that of Group C. CONCLUSIONS: Use of the phrenic nerve as the donor nerve yielded a better outcome than use of the ipsilateral C7 nerve root.

Microsurgical reconstruction of the smile--contemporary trends.

The treatment of facial palsy is a complex and challenging area of plastic surgery. Microsurgical innovation has introduced the modern age of dynamic reconstruction for facial palsy. This review will focus on microsurgical reconstruction for smile restoration in patients with long-standing facial palsy. The most common donor muscles and nerves will be presented. The advantages and disadvantages of single-stage versus multi-stage reconstruction will be discussed. Contemporary trends will be highlighted and the authors' preferred practice outlined.

Recovery of emotional smiling function in free-flap facial reanimation.

PURPOSE: Long-standing unilateral facial palsy is treated primarily with free-flap surgery using the masseteric or contralateral facial nerve as a motor source. The use of a gracilis muscle flap innervated by the masseteric nerve restores the smiling function, without obtaining spontaneity. Because emotional smiling is an important factor in facial reanimation, the facial nerve must serve as the motor source to achieve this fundamental target. MATERIALS AND METHODS: From October 1998 to October 2009, 50 patients affected by long-standing unilateral facial paralysis underwent single-stage free-flap reanimation procedures to recover smiling function. A latissimus dorsi flap innervated by the contralateral facial nerve was transplanted in 40 patients, and a gracilis muscle flap innervated by the masseteric nerve in 10 patients. All patients underwent a clinical examination that analyzed voluntary and spontaneous smiling. RESULTS: All patients who received a latissimus dorsi flap innervated by the contralateral facial nerve and recovered muscle function (92.5%) showed voluntary and spontaneous smiling abilities. All patients who received a gracilis free flap innervated by the masseteric nerve recovered function, but only 1 (10%) showed occasional spontaneous flap activation. During those rare activations, much less movement was visible on the operated side than when the patient was asked to smile voluntarily. CONCLUSIONS: The masseteric nerve is a powerful motor source that guarantees free voluntary gracilis muscle activation; however, it does not guarantee any spontaneous smiling. Single-stage procedures that use a latissimus dorsi flap innervated by the contralateral facial nerve have a lower success rate and obtain less movement; however, spontaneous smiling is always observed.

Split hypoglossal-facial nerve neurorrhaphy for treatment of the paralyzed face.

BACKGROUND: Several methods of neural rehabilitation for facial paralysis using 12-7 transfers have been described. The purpose of this study is to report on a series for dynamic reinnervation of the paralyzed face by using a split 12-7 nerve transposition. The goals of this procedure are to minimize tongue morbidity and to provide good facial reinnervation. METHODS: Prospective case series. Melolabial crease discursion, overall facial movement, and degree of tongue atrophy and mobility were recorded. RESULTS: Thirteen patients underwent facial reanimation using a split hypoglossal-facial nerve transfer with postoperative follow-up to 58 months (range, 6-58 months). All patients achieved excellent rest symmetry and facial tone. Of 13 patients, 10 had measurable coordinated movement and discursion of their melolabial crease. Of 13 patients, 12 had mild to moderate ipsilateral tongue atrophy. The mean time to onset of visible reinnervation was 3 months. CONCLUSION: Split hypoglossal-facial nerve transposition provides good rehabilitation of facial nerve paralysis with reduced lingual morbidity. Long-term rest symmetry and potential learned movement can be achieved. This technique may provide a favorable alternative to the traditional method of complete hypoglossal sacrifice or jump grafting.

Vascular endothelial growth factor and its receptors are expressed in human nerve grafts.

Vascularization and angiogenicity of human nonvascularized nerve grafts in the second stage of facial reanimation were studied. Immunohistochemistry for endothelial markers (CD-31) and vascular endothelial growth factor (VEGF) and its receptors Flt-1 and Flk-1 was performed on distal end biopsies from 35 cross-facial nerve grafts. In grafted nonvascularized nerve, density of vascular structures (also clearly immunopositive for VEGF and both receptors) showed a mean of 166 vessels (range 78 to 267) per unit area, corresponding to control values. In addition, VEGF was expressed in axons and perineural structures. In control samples, VEGF expression was low and occurred in the myelin sheath. In nerve grafts, expression of Flt-1 and Flk-1 (less intense) was seen in axons and perineural structures. A higher density of vessels was associated with lower VEGF expression (not significant). In short, expression of VEGF and its receptors is described in human nerve grafts and compared with basic histology and p75 nerve growth factor receptor expression of the nerve graft and functional outcome of patients.

Facial nerve anastomosis in the mastoid portion using a cable graft. Case report.

We describe a case of a 52-year-old woman in whom surgery for two tumours located in the cerebellar hemisphere and in the posterior petrous bone was complicated by interruption of the facial nerve (CN VII). During the same procedure, anastomosis of CN VII, using a cable graft harvested from the great auricular nerve, was performed. Seven months later the first signs of reinnervation of the facial muscles were noticed. Two and a half years after surgery, CN VII function was assessed as grade II/III according to the House-Brackmann scale. The authors emphasize the significance of immediate repair of CN VII in modern skull base surgery but also the importance of a patient's self-training to obtain the best functional outcome of the facial reanimation. Reconstruction using the great auricular nerve has two significant advantages: first, the patient avoids further procedures for nerve repair, and second, the harvested nerve is located in direct proximity to the operation area.

Microanatomy of the Frontal Branch of the Facial Nerve: The Role of Nerve Caliber and Axonal Capacity.

BACKGROUND: A commonly seen issue in facial palsy patients is brow ptosis caused by paralysis of the frontalis muscle powered by the frontal branch of the facial nerve. Predominantly, static methods are used for correction. Functional restoration concepts include the transfer of the deep temporal branch of the trigeminal nerve and cross-facial nerve grafts. Both techniques can neurotize the original mimic muscles in early cases or power muscle transplants in late cases. Because axonal capacity is particularly important in cross-facial nerve graft procedures, the authors investigated the microanatomical features of the frontal branch to provide the basis for its potential use and to ease intraoperative donor nerve selection. METHODS: Nerve biopsy specimens from 106 fresh-frozen cadaver facial halves were obtained. Histologic processing and digitalization were followed by nerve morphometric analysis and semiautomated axon quantification. RESULTS: The frontal branch showed a median of three fascicles (n = 100; range, one to nine fascicles). A mean axonal capacity of 1191 ± 668 axons (range, 186 to 3539 axons; n = 88) and an average cross-sectional diameter of 1.01 ± 0.26 mm (range, 0.43 to 1.74 mm; n = 67) were noted. In the linear regression model, diameter and axonal capacity demonstrated a positive relation (n = 57; r2 = 0.32; p < 0.001). Based on that equation, a nerve measuring 1 mm is expected to carry 1339 axons. CONCLUSION: The authors' analysis on the microanatomy of the frontal branch could promote clinical use of cross-facial nerve graft procedures in frontalis muscle neurotization and free muscle transplantations.

Repair of whole rabbit facial nerve defects using facial nerve allografts.

PURPOSE: To investigate the feasibility of repairing whole facial nerve defects with chemically extracted acellular whole facial allografts nerves and its effect on motor conductivity recovery. MATERIALS AND METHODS: Whole nerve defects (branches and trunk) were made in 4 rabbit groups (n = 18), and the nerve defect was bridged using 1) acellular facial nerve allografts, 2) facial nerve isografts, 3) acellular peroneal nerve allografts, and 4) peroneal nerve isografts. Six months later, cell morphology, nerve microbeam distribution, angiogenesis, and collagen were observed in the distal and center of the grafts with special trichrome staining. The regenerated nerve fibers and Schwann cells in the anastomosis site were immunohistochemically stained. Nerve axon numbers and passing rates were analyzed with computer-captured images. The regenerated nerve ultrastructure was analyzed by transmission electron microscopy. RESULTS: Regenerated nerve fibers and vessels were found in the grafts, with no differences between groups A and B. Groups C and D had poor nerve continuity with little vascular regeneration. The distal segments of nerve transplants in groups A and B showed strong positive neurofilament staining, higher than in groups C and D. In groups A and B, many long spindle-shaped Schwann cells proliferated longitudinally in the nerve transplant, but less in groups C and D. Myelinated nerve fibers were found in the distal facial nerve. There were no differences between groups A and B in fiber number and myelin sheath thickness, which were much lower than normal, whereas little myelin sheath regeneration was observed in groups C and D. CONCLUSION: Chemically extracted acellular whole facial nerve allografts are feasible for repairing whole facial nerve defects.

Repair of ocular-oral synkinesis of postfacial paralysis using cross-facial nerve grafting.

We present the surgical techniques and results of cross-facial nerve grafting that have been developed in the repair of ocular-oral synkinesis after facial paralysis. Eleven patients with ocular-oral synkinesis after facial paralysis underwent the cross-facial nerve grafting with facial nerve transposition at a tertiary academic hospital between 2003 and 2009. The patient selection for the study was based on the degree of disfigurement and facial function parameter rating using the Toronto Facial Grading System. The procedures used were surgeries done in two stages. All cases were followed up for 2 months to 6 years after the second surgery. The degree of improvement was evaluated at 6 to 7 months after the procedures. Six of the patients were followed up for more than 2 years after the stage-two surgery and demonstrated significant reduction in the ocular-oral synkinetic movements. The Toronto Facial Grading System scores from the postoperative follow-ups increased an average of 16 points (28%), and the patients had achieved symmetrical facial movement. We concluded that cross-facial nerve grafting with facial nerve branch transposition is effective and can be considered as an option for the repair of ocular-oral synkinesis after facial paralysis in select patients.

Fascicular turnover flap in the reconstruction of facial nerve defects: an experimental study in rats.

The purpose of this study was to assess the utility of a fascicular turnover flap for facial nerve repair and to investigate its possible application in the field of facial nerve repair using a rat model of facial paralysis. Twenty-four Wistar rats were used in this study. A left vibrissal muscle palsy model was established via excision of the buccal and marginal branches through a periauricular incision. In Group 1, the nerve gap was not reconstructed. In Group 2, the nerve gap of the marginal mandibular branch was reconstructed using an autograft, and in Group 3, the gap was reconstructed using a fascicular turnover flap. At 12 weeks after the operation, the nerve regeneration was assessed based on clinical, histopathological and electrophysiological evaluations. The functional recovery of the vibrissal muscle was observed with a fascicular turnover flap. The functional recovery of whisker movement was almost same between Groups 2 and 3 (p = .57). The histopathological examinations almost same result between Groups 2 and 3 (p = .17). The compound muscle action potential after reconstruction was also almost same between Groups 2 and 3 (p = .99). We found that the fascicular turnover flap could be applied to facial nerve gap reconstruction. However, further evaluations will be necessary to clarify its indication and mechanism in human.

Facial Nerve Trauma: Clinical Evaluation and Management Strategies.

The field of facial paralysis requires the reconstructive surgeon to apply a wide spectrum of reconstructive and aesthetic principles, using a comprehensive array of surgical tools, including microsurgery, peripheral nerve surgery, and aesthetic facial surgery on the road to optimize patient outcomes. The distinct deficits created by different anatomical levels of facial nerve injury require a fundamental understanding of facial nerve anatomy. Palsy duration, followed by location and mechanism, will determine mimetic muscle salvageability, by means of either direct repair, grafting, or nerve transfers, whereas longer palsy durations will necessitate introducing a new neuromuscular unit, whether by muscle transfer or free functional muscle transplant. A thorough history, physical examination, and basic understanding of ancillary studies, emphasizing palsy duration, location, and mechanism of injury, are critical in evaluation, prognostication, and treatment strategies in traumatic facial palsy patients. The importance of ancillary and aesthetic procedures cannot be overstated. Although these do not provide motion, they constitute essential tools in the treatment of facial paralysis, providing both protective and improved aesthetic outcomes, yielding the highest impact in final surgeon and patient satisfaction, bringing our patients to smile not only on the outside, but also on the inside.

Endoscopic Transcanal Approach to Geniculate Ganglion Hemangioma and Simultaneous Facial Nerve Reinnervation: A Case Report.

Hemangioma of the facial nerve (FN) is a very rare benign tumor whose origin is the vascular plexi that surround the nerve. The transpetrous, retrosigmoid, and middle cranial fossa (MCF) routes are the traditional and most widely used approaches to reach these lateral skull base neoformations. However, this very complex region can be reached through an exclusive transcanal endoscopic procedure in selected cases. One of these was a 42-year-old patient who had been presenting a worsening left FN paralysis (grade VI according to the House-Brackmann scale at the time of visit) for 22 months without a history of trauma or infection. Radiological studies showed a lesion in the region of the geniculate ganglion. A suprageniculate endoscopic approach was performed to remove the lesion, with the sacrifice of the FN and a simultaneous hypoglossal-facial anastomosis. The aim of this minimally invasive surgery is the complete excision of the disease, maintaining the hearing function intact and restoration of facial function, whenever possible, avoiding more invasive approaches.

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

BACKGROUND: Donor nerve myelinated axon counts correlate with functional outcomes in reanimation procedures; however, there exists no reliable means for their intraoperative quantification. In this article, the authors report a novel protocol for rapid quantification of myelinated axons from frozen sections, and demonstrate its applicability to surgical practice. METHODS: The impact of various fixation and FluoroMyelin Red staining strategies on resolved myelin sheath morphology from cryosections of rat and rabbit femoral and sciatic nerves was assessed. A protocol comprising fresh cryosection and rapid staining was developed, and histomorphometric results were compared against conventional osmium-postfixed, resin-embedded, toluidine blue-stained sections of rat sciatic nerve. The rapid protocol was applied for intraoperative quantification of donor nerve myelinated axon count in a cross-facial nerve grafting procedure. RESULTS: Resolution of myelinated axon morphology suitable for counting was realized within 10 minutes of tissue harvest. Although mean myelinated axon diameter appeared larger using the rapid fresh-frozen as compared to conventional nerve processing techniques (mean ± SD; rapid, 9.25 ± 0.62 µm; conventional, 6.05 ± 0.71 µm; p < 0.001), no difference in axon counts was observed on high-power fields (rapid, 429.42 ± 49.32; conventional, 460.32 ± 69.96; p = 0.277). Whole nerve myelinated axon counts using the rapid protocol herein (8435.12 ± 1329.72) were similar to prior reports using conventional osmium processing of rat sciatic nerve. CONCLUSIONS: A rapid protocol for quantification of myelinated axon counts from peripheral nerves using widely available equipment and techniques has been described, rendering possible intraoperative assessment of donor nerve suitability for reanimation.

Effects of Melatonin and Dexamethasone on Facial Nerve Neurorrhaphy.

OBJECTIVES: To investigate the effects of topical and systemic administrations of melatonin and dexamethasone on facial nerve regeneration. MATERIALS AND METHODS: In total, 50 male albino Wistar rats underwent facial nerve axotomy and neurorrhaphy. The animals were divided into 5 groups: control, topical melatonin, systemic melatonin, topical dexamethasone, and systemic dexamethasone. Nerve conduction studies were performed preoperatively and at 3, 6, 9, and 12 weeks after drug administrations. Amplitude and latency of the compound muscle action potentials were recorded. Coapted facial nerves were investigated under light and electron microscopy. Nerve diameter, axon diameter, and myelin thickness were recorded quantitatively. RESULTS: Amplitudes decreased and latencies increased in both the melatonin and dexamethasone groups. At the final examination, the electrophysiological evidence of facial nerve degeneration was not significantly different between the groups. Histopathological examinations revealed the largest nerve diameter in the melatonin groups, followed by the dexamethasone and control groups (p<0.05). Axon diameter of the control group was smaller than those of the melatonin (topical and systemic) and topical dexamethasone groups (p<0.05). The melatonin groups had almost normal myelin ultrastructure. CONCLUSION: Electrophysiological evaluation did not reveal any potential benefit of dexamethasone and melatonin in contrast to histopathological examination, which revealed beneficial effects of melatonin in particular. These agents may increase the regeneration of facial nerves, but electrophysiological evidence of regeneration may appear later.