Autogenous inside-out versus standard vein and skeletal muscle-combined grafting for facial nerve repair

BACKGROUND： In the repair of nerve defects, collapse of the venous wall, as a result of vein grafting alone, could impede nerve regeneration. Therefore, vein lumens filled with muscle and nerve segments have been used to bridge nerve defects. OBJECTIVE： To compare the effects of autogenous, inside-out, vein-skeletal, muscle-combined grafting versus standard, vein-skeletal, muscle-combined grafting for the repair of facial nerve defects. DESIGN, TIME AND SETTING： A randomized, controlled, neuroanatomical, animal study was performed at the Animal Experimental Center and Laboratories of the Capital Medical University Xuanwu Hospital and the Peking Union Medical College Hospital from September 2007 to October 2008.MATERIALS： A total of 10 healthy, male, New Zealand rabbits, aged 6 months, were randomly assigned to inside-out, vein-skeletal, muscle-combined grafting and standard, vein-skeletal, muscle-combined grafting groups, with 5 rabbits in each group. METHODS： A 20-mm gap in the buccal branch of the right facial nerve was made in each animal, which was respectively repaired with inside-out, vein-skeletal, muscle-combined grafts or standard vein-skeletal muscle-combined grafts.MAIN OUTCOME MEASURES： At 6 months after implantation, evoked maximal compound muscle action potentials were recorded on bilateral facial nerves using electromyogram. Myelinated nerve fibers of the regenerating nerves were quantified using myelin sheath osmic acid staining. RESULTS： There was no significant difference between the groups in terms of ratios of bilateral amplitude and latency of compound muscle action potential （P 〉 0.05）. Moreover, morphology of regenerating nerves and quantity of myelinated nerve fibers were similar between the groups （P 〉 0.05）. CONCLUTION： Compared with standard vein grafting, the inside-out vein grafting did not significantly improve nerve regeneration. Therefore, it is not necessary to utilize inside-out vein grafting for the repair of nerve defects, in particular with the combined use of autogenous vein and skeletal muscle grafts.

Artificial facial nerve reflex restores eyelid closure following orbicularis oculi muscle denervation

To date, treatment of peripheral facial paralysis has focused on preservation of facial nerve integrity. However, with seriously damaged facial nerve cases, it is difficult to recover anatomical and functional integrity using present therapies. Therefore, the present study utilized artificial facial nerve reflex to obtain orbicularis oculi muscle （OOM） electromyography signals on the uninjured side through the use of implanted recording electrodes. The implanted electrical chips analyzed facial muscle motion on the uninjured side and triggered an electrical stimulator to emit current pulses, which resulted in stimulation of injured OOM contraction and maintained bilateral symmetry and consistency. Following signal recognition, extraction, and computer analysis, electromyography signals in the uninjured OOM resulted in complete eyelid closure, which was consistent with the voltage threshold for eye closure. These findings suggested that artificial facial nerve reflex through the use of implanted microelectronics in unilateral peripheral facial paralysis could restore eyelid closure following orbicularis oculi muscle denervation.

Classification of facial nerve aberration in congenital malformation of middle ear:Implications for surgery of hearing restoration

Objectives: Facial nerve aberration is the most troublesome situation in congenital malformations of middle ear.The aim of our study is to investigate its imaging and clinical features as well as relevant choice of surgical techniques for hearing improvement.Methods: A retrospective study involving review of clinical data of 227 patients(256 ears) with congenital middle ear anomaly was undertaken, including preoperative computed tomography(CT) data, surgical records and videos.Results: Aberration involving intratemporal facial nerve was found in 82/256 ears(32.03%) with congenital middle ear anomaly. The most common forms of aberration included overhanging over the oval window(50/82 ears, 60.98%), bifurcation(3/82 ears, 3.66%) and transverse over the promontory(3/82 ears, 3.66%), counting for 68.29%(56/82) of the cases with facial nerve aberration. Concomitant stapes malformation was found in 76/82 ears(92.68%) and atresia or stenosis of the oval window in 27/82 ears(32.93%). In 9/82 ears(10.98%) both stapes and oval window was absent. Elective surgeries for the purpose of hearing improvement included stapodotomy + piston implantation, labyrinthotomy, labyrinthotomy + total ossicular replacement prosthesis(TORP) implantation and Vibrant Soundbridge(VSB) implantation.Conclusion: The majority of facial nerve aberration in congenital malformation of middle ear involves displacement of facial nerve, in addition to concomitant malformations of the stapes and/or oval window, which may influence the choice of surgery for hearing improvement. VSB implantation may be considered as a useful option.

Repairing whole facial nerve defects with xenogeneic acellular nerve grafts in rhesus monkeys

Acellular nerve allografts conducted via chemical extraction have achieved satisfactory results in bridging whole facial nerve defects clinically,both in terms of branching a single trunk and in connecting multiple branches of an extratemporal segment.However,in the clinical treatment of facial nerve defects,allogeneic donors are limited.In this experiment,we exposed the left trunk and multiple branches of the extratemporal segment in six rhesus monkeys and dissected a gap of 25 mm to construct a monkey model of a whole left nerve defect.Six monkeys were randomly assigned to an autograft group or a xenogeneic acellular nerve graft group.In the autograft group,the 25-mm whole facial nerve defect was immediately bridged using an autogenous ipsilateral great auricular nerve,and in the xenogeneic acellular nerve graft group,this was done using a xenogeneic acellular nerve graft with trunk-branches.Examinations of facial symmetry,nerve-muscle electrophysiology,retrograde transport of labeled neuronal tracers,and morphology of the regenerated nerve and target muscle at 8 months postoperatively showed that the faces of the monkey appeared to be symmetrical in the static state and slightly asymmetrical during facial movement,and that they could actively close their eyelids completely.The degree of recovery from facial paralysis reached House-Brackmann grade II in both groups.Compound muscle action potentials were recorded and orbicularis oris muscles responded to electro-stimuli on the surgical side in each monkey.Fluoro Gold-labeled neurons could be detected in the facial nuclei on the injured side.Immunohistochemical staining showed abundant neurofilament-200-positive axons and soluble protein-100-positive Schwann cells in the regenerated nerves.A large number of mid-graft myelinated axons were observed via methylene blue staining and a transmission electron microscope.Taken together,our data indicate that xenogeneic acellular nerve grafts from minipigs are safe and effective for repairing whole facial nerve defects in rhesus monkeys,with an effect similar to that of autologous nerve transplantation.Thus,a xenogeneic acellular nerve graft may be a suitable choice for bridging a whole facial nerve defect if no other method is available.The study was approved by the Laboratory Animal Management Committee and the Ethics Review Committee of the Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University,China(approval No.2018-D-1)on March 15,2018.

A Rare Case of Suppurative Parotitis with Facial Nerve Palsy

Parotid mass causing facial nerve palsy is rare, and is associated with malignant tumours. Acute infection or abscess leading to facial nerve palsy is an extremely rare complication. A literature review revealed only 16 cases of facial nerve palsy associated with suppurative parotitis or parotid abscess. We present a case of deep parotid abscess which is complicated by facial nerve dysfunction.

Clinical Benefits of Facial Nerve Monitoring during Cerebellopontine Angle Surgery

Background: The surgery of cerebellopontine angle tumours has remarkably progressed over the last 2 decades due to improved microsurgical techniques. The primary operative goals are microscopic total removal of the tumour while securing the adjacent cranial nerves. Facial Nerve plays a critical role in facial muscles function and one’s cosmetic appearance, and its weakness can have profound implications on a patient’s quality of life. Aim of the Study: To assess the impact of monitoring techniques on the preservation of facial nerve function during cerebellopontine angle tumours surgery. Patients and Methods: This is a prospective study. This study was conducted on 30 cases (2 groups, each had 15 patients) with CPA lesions that had undergone surgical excision of these lesions performed by retrosigmoid approach (Group A: the patients were operated under continuous intraoperative facial nerve monitoring (IOFNM) and Group B: the patients were operated without IOFNM). They were operated upon in neurosurgery departments at Al-Azhar university hospitals between August 2019 and August 2021. Results: This study showed that excellent facial nerve function (HB Grade I and II) was higher in group A than group B, immediately and at 6-month post op (80% and 93% VS 53.3% and 66.7%). Intermediate (HB Grade III and VI) and Poor (HB Grade V and VI) facial nerve function was higher in group B than group A;both immediately and 6-month postop (46.7% and 33.3% VS 20% and 6.6%). However, no statistically significant P-Value between both groups. Conclusion: We concluded that IOFNM can help, but cannot guarantee, the preservation of facial nerve. Furthermore, it is merely a technical adjunct and does not replace surgical skills, knowledge of anatomy and experience.

Styloid Process Is the Robust Landmark for Identification of the Facial Nerve during Parotid Surgery

Objective: To identify the facial nerve trunk (FNT) very easily. quickly and accurately considering the styloid process as the robust anatomically consistent landmark during parotid surgery. Patients and Methods: This prospective study was conducted between January 2010 to December 2022 at a Tertiary care hospital. It included 130 patients: 84 (65%) males and 46 (35%) females with a mean age of 43.52 ± 15.63 years. Patients presented with pleomorphic adenoma (90), chronic sialectasis (05), parotid cyst (03), parotid sinus (01), mucoepidermoid carcinoma (28), adenoid cystic carcinoma (02) and squamous cell carcinoma (01) were subjected to superficial parotidectomy and total parotidectomy. The outcome was evaluated regarding the clinical success of facial nerve function that considered the location of the styloid process in the triangle technique for identification of the FNT during parotid surgery. Results: All 130 patients underwent superficial and total parotidectomy. The facial nerve trunk was successfully identified as the location of the styloid process in the triangle technique in all the patients with no intra-operative complications. Operative time ranged from 50 to 180 minutes with a mean time 90.70 ± 15.68 minutes. Dysfunction of the angle of the mouth due to the deficit of the marginal mandibular nerve (MMN) was noted in 5 patients (3.8%), 02 had difficulty in eye closure (1.5%). No patient reported surgical site infection, skin flap necrosis and hematoma in this series. Conclusion: Styloid process is the prominent robust landmark in the triangle technique for the identification of facial nerve trunk with relative ease, safety and accuracy in the parotid surgical procedure. This can be a very useful method to locate the FNT and minimize facial nerve injury during parotid surgery.

Influence of distal portion compression of facial nerve in hemifacial spasm surgery

Objective To study influence of distal portion compression of facial nerve in hemifacial spasm surgery. Methods 120 hemifacial spasm patients were undergone lateral spread response monitoring during microvascular decompression surgery. 39 patients’LSR remained after decompression of the root exit zone of the facial nerve.

Facial nerve preservation following microsurgical removal of large and huge acoustic neuroma

Objective To evaluate the long-term facial nerve funtion of patients following microsurgical removal of large and huge acoustic neuroma,and to indentify the factors that influence these outcomes. Methods A retrospective review was performed,which included 176 consecutive patients with a

Electroacupuncture promotes peripheral nerve regeneration after facial nerve crush injury and upregulates the expression of glial cell-derived neurotrophic factor

The efficacy of electroacupuncture in the treatment of peripheral facial paralysis is known, but the specific mechanism has not been clarified. Glial cell-derived neurotrophic factor(GDNF) has been shown to protect neurons by binding to N-cadherin. Our previous results have shown that electroacupuncture could increase the expression of N-cadherin mRNA in facial neurons and promote facial nerve regeneration. In this study, the potential mechanisms by which electroacupuncture promotes nerve regeneration were elucidated through assessing the effects of electroacupuncture on GDNF and N-cadherin expression in facial motoneurons of rabbits with peripheral facial nerve crush injury. New Zealand rabbits were randomly divided into a normal group(normal control, n = 21), injury group(n = 45) and electroacupuncture group(n = 45). Model rabbits underwent facial nerve crush injury only. Rabbits in the electroacupuncture group received facial nerve injury, and then underwent electroacupuncture at Yifeng(TE17), Jiache(ST6), Sibai(ST2), Dicang(ST4), Yangbai(GB14), Quanliao(SI18), and Hegu(LI4; only acupuncture, no electrical stimulation). The results showed that in behavioral assessments, the total scores of blink reflex, vibrissae movement, and position of apex nasi, were markedly lower in the EA group than those in the injury group. Hematoxylin-eosin staining of the right buccinator muscle of each group showed that the cross-sectional area of buccinator was larger in the electroacupuncture group than in the injury group on days 1, 14 and 21 post-surgery. Toluidine blue staining of the right facial nerve tissue of each group revealed that on day 14 post-surgery, there was less axonal demyelination and fewer inflammatory cells in the electroacupuncture group compared with the injury group. Quantitative real time-polymerase chain reaction showed that compared with the injury group, N-cadherin mRNA levels on days 4, 7, 14 and 21 and GDNF mRNA levels on days 4, 7 and 14 were significantly higher in the electroacupuncture group. Western blot assay displayed that compared with the injury group, the expression of GDNF protein levels on days 7, 14 and 21 were significantly upregulated in the electroacupuncture group. The histology with hematoxylin-eosin staining and Nissl staining of brainstem tissues containing facial neurons in the middle and lower part of the pons exhibited that on day 7 post-surgery, there were significantly fewer apoptotic neurons in the electroacupuncture group than in the injury group. By day 21, there was no significantly difference in the number of neurons between the electroacupuncture and normal groups. Taken together, these results have confirmed that electroacupuncture promotes regeneration of peripheral facial nerve injury in rabbits, inhibits neuronal apoptosis, and reduces peripheral inflammatory response, resulting in the recovery of facial muscle function. This is achieved by up-regulating the expression of GDNF and N-cadherin in central facial neurons.

Olfactory ensheathing cells promote nerve regeneration and functional recovery after facial nerve defects

Olfactory ensheathing cells from the olfactory bulb and olfactory mucosa have been tbund to increase axonal sprouting and pathfinding and promote the recovery of vibrissae motor performance in facial nerve transection injured rats. However, it is not yet clear whether olfactory ensheathing cells promote the reparation of facial nerve defects in rats. In this study, a collagen sponge and silicone tube neural conduit was implanted into the 6-mm defect of the buccal branch of the facial nerve in adult rats. Olfactory ensheathing cells isolated from the olfactory bulb of newborn Sprague-Dawley rats were injected into the neural conduits connecting the ends of tile broken nerves, the morphology and function of the regenerated nerves were compared between the rats implanted with olfactory ensheathing cells with the rats injected with saline. Facial paralysis was assessed. Nerve electrography was used to measure facial nerve-induced action potentials. Visual inspection, anatomical microscopy and hematoxylin-eosin staining were used to assess the histomorphology around the trans planted neural conduit and the morphology of the regenerated nerve. Using fluorogold retrograde tracing, toluidine blue staining and lead uranyl acetate staining, we also measured the number of neurons in the anterior exterior lateral f：acial nerve motor nucleus, the number of myelinated nerve fibers, and nerve fiber diameter and myelin sheath thickness, respectively. After surgery, olfactory ensheathing cells de- creased facial paralysis and the latency of the facial nerve-induced action potentials. There were no differences in the general morphology of the regenerating nerves between the rats implanted with olfactory ensheathing cells and the rats injected with saline. Between-group results showed that olfactory ensheathing cell treatment increased the number of regenerated neurons, improved nerve fiber morphology, and increased the number of myelinated nerve fibers, nerve fiber diameter, and myelin sheath thickness. In conclusion, implantation of olfactory ensheathing cells can promote regeneration and functional recovery after facial nerve damage in rats.

Scala tympani drill-out technique for oval window atresia with malformed facial nerve: A report of three cases

Objective: To report a scala tympani drill-out technique for managing malformed facial nerve covering the entire oval window(OW).Methods: Data from three cases with OW atresia, malformed stapes and abnormal facial nerve courses were reported, in which a scala tympani drill-out technique was employed with a TORP between the tympanic membrane and scala tympani fenestration for hearing reconstruction.Results: Air conduction hearing improved in two of the three cases following surgery. In the third case, there was no improvement in air conduction hearing following a canal wall up mastoidectomy and tympanoplasty. There were no vertigo, tinnitus or sensorineural hearing loss in the three cases.Conclusion: The scala tympani drill-out technique, which is basically fenestration at the initial part of the basal turn, provides a choice in hearing reconstruction when the OW is completely covered by abarrently coursed facial nerve.

Facial nerve paralysis in children

Facial nerve palsy is a condition with several implications, particularly when occurring in childhood. It represents a serious clinical problem as it causes significant concerns in doctors because of its etiology, its treatment options and its outcome, as well as in little patients and their parents, because of functional and aesthetic outcomes. There are several described causes of facial nerve paralysis in children, as it can be congenital(due to delivery traumas and genetic or malformative diseases) or acquired(due to infective,inflammatory, neoplastic, traumatic or iatrogenic causes). Nonetheless, in approximately 40%-75% of the cases, the cause of unilateral facial paralysis still remains idiopathic. A careful diagnostic workout and differential diagnosis are particularly recommended in case of pediatric facial nerve palsy, in order to establish the most appropriate treatment, as the therapeutic approach differs in relation to the etiology.

Facial reanimation with interposition nerve graft or masseter nerve transfer:a comparative retrospective study

Both interposition nerve grafts and masseter nerve transfers have been successfully used for facial reanimation after irreversible injuries to the cranial portion of the facial nerve.However,no comparative study of these two procedures has yet been reported.In this two-site,twoarm,retrospective case review study,32 patients were included.Of these,17 patients(eight men and nine women,mean age 42.1 years)underwent interposition nerve graft after tumor extirpation or trauma between 2003 and 2006 in the Ear Institute,School of Medicine,Shanghai Jiao Tong University,China,and 15 patients(six men and nine women,mean age 40.6 years)underwent masseter-to-facial nerve transfer after tumor extirpation or trauma between November 2010 and February 2016 in Shanghai Ninth People's Hospital,China.More patients achieved House-Brackmann III recovery after masseter nerve repair than interposition nerve graft repair(15/15 vs.12/17).The mean oral commissure excursion ratio was also higher in patients who underwent masseter nerve transfer than in patients subjected to an interposition nerve graft.These findings suggest that masseter nerve transfer results in strong oral commissure excursion,avoiding obvious synkinesis,while an interposition nerve graft provides better resting symmetry.This study was approved by the Institutional Ethics Committee,Shanghai Ninth People's Hospital,China(approval No.SH9 H-2019-T332-1)on December 12,2019.

Intraparotid facial nerve schwannoma: A case report

Facial nerve schwannoma occurring within the parotid gland is a rare tumour. We report a case of schwannoma within the parotid gland in a young female patient, who underwent ultrasound and magnetic resonanceimaging(MRI) and subsequent surgical excision of the lesion. The lesion showed hyperintensity on T2-weighted and diffusion-weighted MRI. There was no adjacent lymphadenopathy. Although hyperintensity on diffusionweighted MRI could suggest malignant tumours, the characteristic "string sign" provided the clue for the diagnosis of schwannoma.

Immunobiology of Facial Nerve Repair and Regeneration

Immunobiological study is a key to revealing the important basis of facial nerve repair and regeneration for both research and development of clinic treatments. The microenvironmental changes around an injuried facial motoneuron, i.e., the aggregation and expression of various types of immune cells and molecules in a dynamic equilibrium, impenetrate from the start to the end of the repair of an injured facial nerve. The concept of 'immune microenvironment for facial nerve repair and regeneration', mainly concerns with the dynamic exchange between expression and regulation networks and a variaty of immune cells and immune molecules in the process of facial nerve repair and regeneration for the maintenance of a immune microenvironment favorable for nerve repair. Investigation on microglial activation and recruitment, T cell behavior, cytokine networks, and immunological cellular and molecular signaling pathways in facial nerve repair and regeneration are the current hot spots in the research on immunobiology of facial nerve injury. The current paper provides a comprehensive review of the above mentioned issues. Research of these issues will eventually make immunological interventions practicable treatments for facial nerve injury in the clinic.

Negative regulation of gamma-aminobutyric acid type A receptor on free calcium ion levels following facial nerve injury

Previous studies have demonstrated that muscarinic, and nicotinic receptors increase free Ca2＋ levels in the facial nerve nucleus via various channels following facial nerve injury. However, intracellular Ca2＋ overload can trigger either necrotic or apoptotic cell death. Gamma-aminobutyric acid （GABA）, an important inhibitory neurotransmitter in the central nervous system, exists in the facial nerve nucleus. It is assumed that GABA negatively regulates free Ca2＋ levels in the facial nerve nucleus. The present study investigated GABA type A （GABAA） receptor expression in the facial nerve nucleus in a rat model of facial nerve injury using immunohistochemistry and laser confocal microscopy, as well as the regulatory effects of GABAA receptor on nicotinic receptor response following facial nerve injury. Subunits α1, α3, α5, β1, β2, δ, and γ3 of GABAA receptors were expressed in the facial nerve nucleus following facial nerve injury. In addition, GABAA receptor expression significantly inhibited the increase in nicotinic receptor-mediated free Ca2＋ levels in the facial nerve nucleus following facial nerve injury in a concentration-dependent fashion. These results suggest that GABAA receptors exhibit negative effects on nicotinic receptor responses following facial nerve injury.

Muscarinic receptor-mediated calcium changes in a rat model of facial nerve nucleus injury

The muscarinic receptor modulates intracellular free calcium ion levels in the facial nerve nucleus via different channels. In the present study, muscarinic receptor-mediated free calcium ions levels were detected by confocal laser microscopy in the facial nerve nucleus following facial nerve injury in rats. There was no significant difference in muscarinic receptor expression at the affected facial nerve nucleus compared with expression prior to injury, but muscarinic receptor-mediated free calcium ion levels increased in the affected side following facial nerve injury （P 〈 0.01）. At day 30 after facial nerve injury, 50 pmol/L muscarinic-mediated free calcium ion levels were significantly inhibited at the affected facial nerve nucleus in calcium-free artificial cerebrospinal fluid, and the change range was 82% of artificial cerebrospinal fluid （P 〈 0.05）. These results suggest that increased free calcium ion concentrations are achieved by intracellular calcium ion release, and that the transmembrane flow of calcium ions is also involved in this process.

Application of a venous conduit as a stent for repairing rabbit facial nerve injury

BACKGROUND： Recently, many investigators have tried to use natural biomaterials, such as, artery, vein, decalcified bone, etc., as conduits for nerve repair. However, immunological rejection of conduits made of natural biomaterials limits their application. Therefore, it is essential to identify more suitable types of biomaterials. OBJECTIVE： To observe the characteristics of a bioengineering processing method using venous conduit as a stent for repairing facial nerve injury. DESIGN： A controlled observational experiment. SETTING： Animal Laboratories of the Third Hospital Affiliated to Sun Yat-sen University and the 157 Hospital. MATERIALS： Thirty-three male New Zealand rabbits of pure breed, weighing 1.5 to 2.0 kg, were provided by Medical Experimental Animal Room of Sun Yat-sen University. The protocol was carried out in accordance with animal ethics guidelines for the use and care of animals. Venous conduits and autogenous nerves were transplanted into the left and right cheeks, respectively. Eleven animals were chosen for anatomical observations at 5, 10 and 15 weeks after surgery. METHODS： This experiment was carried out in the Animal Laboratories of the Third Hospital Affdiated to Sun Yat-sen University and the 157 Hospital between May and November 2006. After animals were anesthetized, 15 mm of retromandibular vein was harvested for preparing a venous conduit. Approximately 3 cm of low buccal branch of facial nerve was exposed. A segment of 1.2 cm nerve was resected from the middle, and a gap of 1.5 cm formed due to bilateral retraction. The prepared venous conduit of 1.5 cm was sutured to the outer membrane of the severed ends of the nerve. Muscle and skin were sutured layer by layer. Using the same above-mentioned method, the low buccal branch of right autogenous facial nerve was resected, and the left facial nerve segment from the same animal was transplanted using end-to-end neurorrhaphy for control. MAIN OUTCOME MEASURES： （1）Post-operatively, food intake, vibrissae activity and wound healing of each animal were observed daily. （2） Animals were anesthetized at 5, 10 and 15 weeks after operation for observing the structural change of the venous conduit, the appearance of regenerated nerve, and the relationship between conduit and peripheral muscle tissue. （3） The action potential and latency of bilateral nerves of animals were measured by electrophysiologic examination, and nerve conduction velocity was calculated. （4）Neural myelination and neurite growth were observed by histological staining using an optical microscope. RESULTS： Thirty-three New Zealand rabbits were involved in the final analysis. （1）Immediately following the operation, vibrissae activity and orbicularis otis muscle activity of the upper lip on venous conduit side were more prominent, and their amplitudes of movement were larger as compared with autogenous nerve side. （2） At postoperative 10 weeks, by visual inspection, we found that on the venous conduit side, the venous conduit exhibited membrane structure which encased regenerated nerve. Regenerated nerve adhered to the muscle edge of orbicularis oris muscle. Muscle and nerve could be separated with a forceps. The muscle of musculus orbicularis oris of rabbit was darker and thicker as compared with autogenous nerve side. After the venous conduit was longitudinally split, the regenerated nerve and nerves at two the severed ends were connected together. When compared with postoperative 5 weeks, the connected nerve was thickened, texture was tough and its middle part was thicker than its two ends. On the autogenous nerve side, the regenerated nerve stem was enwrapped by scar tissue. It was bulky and adhered to peripheral muscle. Its neural profile structure was unclear. The two stomas were obviously enlarged. （3）At postoperative 10 weeks and 15 weeks, nerve action potentials could be elicited from both the venous conduit and autologous nerve side. The mean nerve conduction velocity on the venous conduit side was greater than that of the autologous nerve side. （4）At postoperative 10 weeks, using histochemical staining, it was found that in the venous conduit, regenerated medullated nerve fibers were densely distributed, with well split facial nerve structure, while on the autologous nerve side, nerve fibers were sparsely scattered, with immature medullated nerve structure. CONCLUSION： Biological natural venous conduit processed by bioengineering technology overcomes the tissue inflammatory reactions and connective tissue reactions caused by natural biomaterials. It is more conducive to promote neural regeneration and functional recovery than autologous nerve transplantation.

Agmatine promotes expression of brain-derived neurotrophic factor in brainstem facial nucleus in the rat facial nerve injury model

BACKGROUND： Studies have shown that agmatine can reduce inhibition of neuronal regeneration by increasing cyclic adenosine monophosphate and brain-derived neurotrophic factor （BDNF） in the hippocampus of morphine-dependent rats. The hypothesis that agmatine exerts similar effects on facial nerve injury deserves further analysis. OBJECTIVE： To study the effects of peritoneal agmatine injection on BDNF levels in the rat brainstem after facial nerve injury. DESIGN, TIME AND SETTING： A controlled animal experiment was performed at the Department of Otolaryngology-Head and Neck Surgery at the Second Affiliated Hospital, Chongqing University of Medical Sciences （Chongqing, China）, between October and December in 2007. MATERIALS： Twenty-four male Sprague-Dawley rats were randomly divided into a control, a lesion, and an agmatine treatment group, with eight rats in each group. Bilateral facial nerve anastomosis was induced in the lesion and agmatine treatment groups, while the control group remained untreated. A rat BDNF Enzyme-linked immunosorbent assay kit was used to measure BDNF levels in the brainstem facial nucleus. METHODS： Starting on the day of lesion, the agmatine group received a peritoneal injection of 100 mg/kg agmatine, once per day, for a week, whereas rats in the lesion group received saline injections. MAIN OUTCOME MEASURES： BDNF levels in the brainstem containing facial nucleus were measured by ELISA. RESULTS： Twenty-four rats were included in the final analysis without any loss. Two weeks after lesion, BDNF levels were significantly higher in the lesion group than in the control group （P 〈 0.01）. A significant increase was noted in the agmatine group compared to the lesion group （P 〈 0.01）. CONCLUSION： Agmatine can substantially increase BDNF levels in the rat brainstem after facial nerve injury.