2-Chloroethylamine·trifluoromethanesulfonate combined with 18-crown-6: a ferroelectric with excellent dielectric switching properties.

Ferroelectric materials are not only important electronic functional materials, but also considered as the most promising intelligent basic materials, because they show good application prospects. Therefore, it is an urgent task to develop and explore new ferroelectric material systems. In addition, the most important feature of crown ethers is their ability to complex with positive ions, which is extremely useful in synthesis. We report that [NH3C2H4Cl(18-crown-6)](CF3SO3) (1) has a phase transition temperature Tc = 255 K, and there is an obvious SHG switch below Tc. At the same time, the saturation polarization value Ps = 1.25 µC cm-2 is obtained from the hysteresis loop, which directly proves the ferroelectric nature of compound 1. It is noteworthy that the second harmonic response test of compound 1 shows a symmetric transition from a non-centrosymmetric to a centrosymmetric point group, that is a symmetry break from the paraelectric phase to the ferroelectric phase. This work is expected to promote the further exploration of organic crown ether ferroelectrics and provide a way to design and synthesize organic crown ether ferroelectrics.

Zero-Dimensional Sn-Based Enantiomeric Phase-Transition Materials with High-Tc and Dielectric Switching.

The combination of chirality and phase-transition materials has broad application prospects. Therefore, based on the quasi-spherical theory and the thought strategy of introducing chirality, we have successfully synthesized a pair of chiral enantiomeric ligands (R/S)-triethyl-(2-hydroxypropyl)ammonium iodide, which can be combined with a tin hexachloride anion to obtain a pair of new organic-inorganic hybrid enantiomeric high-temperature plastic phase-transition materials: (R/S)-[CH3 CH(OH)CH2 N(CH2 CH3 )3 ]2 SnCl6 (1-R/1-S), which have a high temperature phase transition of Tc =384 K, crystallize in the P21 chiral space group at room temperature, and have obvious CD signals. In addition, compounds 1-R and 1-S have a good low-loss dielectric switch and broadband gap. This work is conducive to the research into chiral high-temperature reversible plastic phase-transition materials, and promotes the development of multi-functional phase-transition materials.

Large Spontaneous Polarization Ferroelectric Property, Switchable Second-Harmonic Generation Responses, and Magnetism in an Fe-Based Compound.

Since the switchable spontaneous polarization of ferroelectric materials endows it with many useful properties such as a large pyroelectric coefficient, switchable spontaneous polarization, and semiconductor, it has a wide range of application prospects, and the research of high-performance molecular ferroelectric materials has become a hot spot. We obtained a 0D organic-inorganic hybrid ferroelectric [(CH3)3NCH2CH2CH3]2FeCl4 (1) with well-defined ferroelectric domains and excellent domain inversion and exhibited a relatively large spontaneous polarization (Ps = 9 µC/m-2) and a Curie temperature (Tc) of 394 K. Furthermore, compound 1 belongs to the non-centrosymmetrical space group Cmc21 and has a strong second-harmonic generation signal. Interestingly, we also performed magnetic tests on 1, which confirmed that it is a magnetic material. This work provides clues for exploring the application of high-performance molecular ferroelectric materials in future multifunctional smart devices.

High-Tc 1D Phase-Transition Semiconductor Photoluminescent Material with Broadband Emission.

One dimensional (1D) organic-inorganic halide hybrid perovskites have the advantages of excellent organic cation modifiability and diversity of inorganic framework structures, which cannot be ignored in the development of multi-functional phase-transition materials in photoelectric and photovoltaic devices. Here, we have successfully modified and synthesized an organic-inorganic hybrid perovskite photoelectric multifunctional phase-transition material: [C7 H13 ONCH2 F]⋅PbBr3 (1). The synergistic effect of the order double disorder transition of organic cations and the change of the degree of distortion of the inorganic framework leads to its high temperature reversible phase-transition point of Tc =374 K/346 K and its ultra-low loss high-quality dielectric switch response. Through in-depth research and calculation, compound 1 also has excellent semiconductor characteristics with a band gap of 3.06 eV and the photoluminescence characteristics of self-trapped exciton (STE) broadband emission. Undoubtedly, this modification strategy provides a new choice for the research field of organic-inorganic hybrid perovskite reversible phase-transition photoelectric multifunctional materials with rich coupling properties.

Unusual symmetry breaking in high-temperature enantiomeric ferroelectrics with large spontaneous polarization.

Chiral organic-inorganic hybrid perovskites have gained extensive research interest due to their combination of chirality and the excellent optical, electrical and spin properties of perovskite materials, especially in two-dimensional hybrid perovskites. Herein, we report two-dimensional organic-inorganic perovskite enantiomeric ferroelectric [(R)-ß-MPA]2CdCl4 (1) and [(S)-ß-MPA]2CdCl4 (2) (MPA+ =methylphenethylammonium). Their mirror relationships are verified by both circular dichroism (CD) and crystal structures. At the same time, the two exhibit very similar ferroelectricity and related properties, including high Curie temperature (343 K), large spontaneous polarization (4.65 µC cm-2), and low coercive force field (13 kV cm-1). Unusually, at room temperature the crystal phase is monoclinic with the space group C2 and above the phase transition temperature it is triclinic with the space group P1, which means that the symmetry decreases with the increase of temperature. In addition, it exhibits a flexible switchable SHG response, while [(R)-ß-MPA]2CdCl4 and [(S)-ß-MPA]2CdCl4 have wide band gaps of 4.21 and 4.26 eV, respectively, mainly contributed by inorganic CdCl6 octahedra. This discovery opens a new way for the construction of two-dimensional enantiomeric molecular ferroelectrics.

High-Temperature Phase Transition Containing Switchable Dielectric Behavior, Long Fluorescence Lifetime, and Distinct Photoluminescence Changes in a 2D Hybrid CuBr4 Perovskite.

A novel organic-inorganic hybrid perovskite crystal, [ClC6H4(CH2)2NH3]2CuBr4 (1), having experienced an invertible high-temperature phase transition near Tc (the Curie temperature Tc = 355 K), has been successfully synthesized. The phase-transition characteristics for compound 1 are thoroughly revealed by specific heat capacity (Cp), differential thermal analysis, and differential scanning calorimetry tests, possessing 16 K broad thermal hysteresis. Multiple-temperature powder X-ray diffraction analysis further proves the phase-transition behavior of compound 1. Moreover, compound 1 exhibits a significant steplike dielectric response near Tc, revealing that it can be deemed to be a promising dielectric switching material. The variable-temperature fluorescence experiments show distinct photoluminescence (PL) changes of compound 1. Further investigation and calculation disclose that the fluorescence lifetime of compound 1 can reach as long as 55.46 µs, indicating that it can be a potential PL material. All of these researches contribute a substitutable avenue in the design and construction of neoteric phase-transition compounds combining high Curie temperature and PL properties.

A multifunctional molecular ferroelectric with chiral features, a high Curie temperature, large spontaneous polarization and photoluminescence: (C9H14N)2CdBr4.

Low-dimensional chiral organic-inorganic hybrid metal halides have attracted a lot of attention in recent years due to their unique intrinsic properties, including having potential applications in optoelectronic and spintronic devices. However, low-dimensional chiral molecular ferroelectrics are very rare. In this paper, we report a novel zero-dimensional molecular ferroelectric (C9H14N)2CdBr4 (C9H14N+ = protonated 3-phenylpropylamine), which has obvious dielectric and thermal anomalies and shows a high Curie temperature at 395 K. It crystallizes in the P21 space group at room temperature, showing a strong CD signal, large spontaneous polarization (P s = 13.5 µC cm-2), and a clear ferroelectric domain. In addition, it also exhibits a flexible SHG response. The photoluminescence spectrum shows that 1 has broadband luminescence. At the same time, compound 1 has a wide band gap, which is mainly contributed to by the inorganic CdBr4 tetrahedron. The high tunability of low-dimensional chiral molecular ferroelectrics also opens up a way to explore multifunctional chiral materials.

Microvascular Decompression Alone without Rhizotomy Is an Effective Way of Treating Glossopharyngeal Neuralgia: Clinical Analysis of 46 Cases.

BACKGROUND: Microvascular decompression (MVD) has been the right choice for glossopharyngeal neuralgia (GPN) patients. However, whether glossopharyngeal/vagal nerve root rhizotomy should be combined with MVD is still controversial. OBJECTIVE: To evaluate whether glossopharyngeal/vagal nerve root rhizotomy during MVD is necessary for the treatment of GPN. METHODS: We performed a retrospective study of 46 GPN patients who underwent MVD surgery alone in our hospital, and their patient demographics, clinical presentations, and intraoperative findings are shown. The immediate and long-term follow-up outcomes were investigated to show the treatment's efficiency and safety; the outcome was also compared with our previous study. The relevant literature was reviewed to show complications for GPN patients undergoing glossopharyngeal/vagal nerve root rhizotomy with MVD. RESULTS: The most common offending vessel was the posterior inferior cerebellar artery (60.9%). 100% of the patients were pain-free (score of I on the Barrow Neurological Institute pain intensity [BNI-P] scale) immediately after MVD surgery, while 1 patient relapsed with occasional pain 12 months after the operation (score of III on the BNI-P scale). Poor wound healing and hearing loss were found in 1 case each. No complications related to the glossopharyngeal nerve/vagal nerve were reported. Some surgical techniques, such as thorough exploration of the CN IX-X rootlets, full freeing from arachnoid adhesions, and usage of a moist gelatin sponge, can improve the success rate of the operation. CONCLUSIONS: MVD alone without rhizotomy is an effective and safe method for patients with GPN.

Surgical Treatment of Hemifacial Spasm Caused by the Compression of Internal Auditory Canal of Facial Nerve.

OBJECTIVE: To make out the way to distinguish the offending vessels compressed the internal auditory canal part of the facial nerve. METHODS: The hemifacial spasm patients were treated of microvascular decompression surgery with neurophysiologic monitoring. The patients were found that the internal auditory canal of the facial nerves was fully compressed, and the records of surgery monitoring were analyzed. RESULTS: All the patients were recorded the delay incubation period in electromyography monitoring, and all patients were hemifacial spasm free finally. CONCLUSION: Some hemifacial spasms were caused by internal auditory canal compression, so during the operation, the authors should explore the whole course of the facial nerve and compress the internal auditory canal part with the aid of neurophysiologic monitoring.

Operative Complications of Microvascular Decompression for Hemifacial Spasm: Experience of 1548 Cases.

BACKGROUND: Although microvascular decompression (MVD) surgery is considered the gold standard treatment for hemifacial spasm, there are some MVD-related complications. METHODS: We retrospectively reviewed 1548 patients with hemifacial spasm who underwent retromastoid suboccipital craniectomy with MVD from January 2009 to June 2013. All patients were followed for >2 years. RESULTS: Excellent and good results were 92.5% and 4.2%, respectively. Postoperative complications were recorded in 16.09% (n = 249). There was no MVD-related mortality. After MVD surgery, the most frequent complications were occipital sensory disturbance (7.3%), facial nerve palsy (9.7%), and hearing impairment (3.5%). Other complications were as follows: cerebrospinal fluid leakage (n = 24), poor healing wound (n = 14), lower cranial nerve palsy (n = 12), wound infection (n = 4), and hemorrhage (n = 2). CONCLUSIONS: MVD operation is a safe treatment for hemifacial spasm. Facial nerve palsy is the most common MVD-related complication; preservation of the lesser occipital nerve during MVD surgery can decrease the rate of occipital sensory disturbance. Permanent or serious complications are comparatively rare in MVD surgery.

Utility of Brainstem Trigeminal Evoked Potentials in Patients With Primary Trigeminal Neuralgia Treated by Microvascular Decompression.

OBJECTIVE: To investigate the characteristics of brainstem trigeminal evoked potentials (BTEP) waveform in patients with and without trigeminal neuralgia (TN), and to discuss the utility of BTEP in patients with primary TN treated by microvascular decompression (MVD). METHODS: A retrospective review of 43 patients who underwent BTEP between January 2016 and June 2016, including 33 patients with TN who underwent MVD and 10 patients without TN. Brainstem trigeminal evoked potentials characteristics of TN and non-TN were summarized, in particular to compare the BTEP changes between pre- and post-MVD, and to discover the relationship between BTEP changes and surgical outcome. RESULTS: Brainstem trigeminal evoked potentials can be recorded in patients without trigeminal neuralgia. Abnormal BTEP could be recorded when different branches were stimulated. After decompression, the original W2, W3 disappeared and then replaced by a large wave in most patients, or original wave poorly differentiated improved in some patients, showed as shorter latency and (or) amplitude increased. Brainstem trigeminal evoked potentials waveform of healthy side in patients with trigeminal neuralgia was similar to the waveform of patients without TN. In 3 patients, after decompression the W2, W3 peaks increased, and the latency, duration, IPLD did not change significantly. Until discharge, 87.9% (29/33) of the patients presented complete absence of pain without medication (BNI I) and 93.9% (31/33) had good pain control without medication (BNI I-II). CONCLUSION: Brainstem trigeminal evoked potentials can reflect the conduction function of the trigeminal nerve to evaluate the functional level of the trigeminal nerve conduction pathway. The improvement and restoration of BTEP waveforms are closely related to the postoperative curative effect.

Results of Atypical Hemifacial Spasm with Microvascular Decompression: 14 Case Reports and Literature Review.

BACKGROUND: Few studies have examined atypical hemifacial spasm (AHFS), and the mechanism of AHFS remains unclear. In this study, we examined the etiology, prognosis, and treatment of AHFS. METHODS: We retrospectively analyzed the clinical data for 14 consecutive patients that underwent microvascular decompression (MVD) for AHFS between January 2014 and December 2015. Clinical features, outcomes, and complications were evaluated. RESULTS: The incidence of AHFS is 1.52%. There were no significant differences in sex, age, side and duration between the typical hemifacial spasm and AHFS. During the follow-up period, the effective rate of MVD for patients with AHFS was 92.3%. Three patients developed delayed facial nerve palsy postoperatively, 1 patient experienced occipital sensory disturbance, and 1 patient suffered hearing loss. CONCLUSIONS: Most of the cases of AHFS studied here were caused by neurovascular conflict in zone IV of the facial nerve distal to the root entry zone. MVD surgery is the first choice treatment for AHFS.

Electromyographically Guided Nerve Combing Makes Microvascular Decompression More Successful in Hemifacial Spasm with Persistent Abnormal Muscle Response.

BACKGROUND: Microvascular decompression (MVD) of the facial nerve monitored intraoperatively by abnormal muscle response (AMR) activity is a common treatment for hemifacial spasm. AMR frequently persists after MVD, however, for which electromyography (EMG)-guided nerve combing sometimes is recommended. Because no research regarding the success of EMG-guided nerve combing has been published, we compared the effectiveness of nerve combing after MVD with simple MVD in cases including persistent AMR. METHODS: A retrospective study of 127 cases of hemifacial spasm treated with persistent AMR after MVD treatment occurring between January 2011 and June 2015 was conducted. Among the 127 total cases, EMG-guided nerve combing was used in 72 patients and simple MVD in 55 patients. RESULTS: For simple MVD, success rates at 1 day, 7 days, 1 month, 3 months, and 1 year after surgery were all approximately 80%; the success rates of MVD with nerve combing were significantly greater (P < 0.05) than those of simple MVD, by 15.83%, 15.4%, 17.22%, 17.65%, and 17.65%, respectively. The incidence rates of facial palsy in simple MVD were 12.73%, 14.55%, 10.91%, 3.64%, and 1.82%, respectively; those in the nerve combing group were 27.78% (P < 0.05 vs. simple MVD), 33.33% (P < 0.05), 25.00% (P = 0.05), 5.55% (P > 0.05), and 2.78% (P > 0.05), respectively. CONCLUSIONS: In cases of hemifacial spasm with persistent AMR after MVD, EMG-guided nerve combing significantly improved the success rate of the operation. Although it also significantly increased the incidence of postoperative facial palsy over the short term (up to 1 week), incidences in the long term were not significantly different.

The Effects of Dual Abnormal Muscle Response Monitoring on Microvascular Decompression in Patients with Hemifacial Spasm.

BACKGROUND: Microvascular decompression (MVD) is the most useful treatment for hemifacial spasm (HFS). During MVD surgery, traditional abnormal muscle response (tAMR) is widely used to monitor success in decompressing the facial nerve. Dual AMR (dAMR) is a new monitoring method used during MVD for HFS. We compared the sensitivities and reliabilities of tAMR and dAMR. METHODS: We performed a retrospective study of 1301 cases of HFS treated using MVD between January 2014 and March 2016. Among the 1301 cases, 587 patients underwent tAMR monitoring and 714 underwent dAMR monitoring. RESULTS: Typical abnormal muscle response (AMR) waveforms were observed in 484 patients (82.5%) in the tAMR group and in 688 patients (96.4%) in the dAMR group (P < 0.05). AMR waveforms disappeared in 459 patients in the tAMR group and in 655 patients in the dAMR group during MVD. One day, 7 days, 1 month, and 3 months after MVD surgeries with AMR disappearance, the effective rate of MVD was 95.0%, 94.3%, 94.5%, and 95.0%, respectively, in the tAMR group. The corresponding rates were 97.7%, 96.9%, 97.3%, and 98.0% in the dAMR group (P < 0.05). One day, 7 days, 1 month, and 3 months after MVD surgeries with AMR persistence, the effective rate of MVD was 68.0%, 64.0%, 64.0%, and 64.0%, respectively, in the tAMR group. The corresponding rates were 90.9%, 87.9%, 87.9%, and 90.9% in the dAMR group (P < 0.05). CONCLUSIONS: AMR monitoring provides valuable neurosurgical guidance during MVD for HFS. dAMR monitoring has better sensitivity and reliability than tAMR monitoring.

Factors Promoting a Good Outcome in a Second Microvascular Decompression Operation When Hemifacial Spasm is Not Relieved After the Initial Operation.

BACKGROUND: Microvascular decompression (MVD) has become the best treatment for hemifacial spasm (HFS); however, some patients do not obtain complete relief after the initial MVD. We analyzed a group of patients who underwent a second MVD, to identify the factors that prevented relief after the initial MVD and those that promote the success of the second procedure. METHODS: Of a group of 1400 patients with typical primary unilateral HFS treated with MVD between January 2014 and October 2015, we focused on 42 patients with poor postoperative outcomes. All patients underwent abnormal muscle response (AMR) monitoring again the day after surgery. Of those patients, 35 underwent a second MVD surgery within a week. We analyzed their AMRs after each operation. RESULTS: After the first operation, AMR was positive in 40 patients and negative in 2 patients. The latter 2 patients reported spontaneous relief within 1 week. Among the 40 positive patients, 35 and 4 patients underwent a second MVD within a week and 6-11 months, respectively. Thirty-nine patients reported relief after the second MVD; 1 patient remained unchanged at follow-up (<12 months). CONCLUSIONS: When initial MVD does not provide relief, a repeat MVD should be performed as soon as possible. In 2/42 cases, relief was delayed enough that AMR had a false-negative result. Combinative monitoring of AMR and Z-L responses was important in identifying the real cause of HFS.

Microvascular Decompression for Trigeminal Neuralgia: Zone Exploration and Decompression Techniques.

OBJECTIVE: The aim of this study is to introduce zone exploration of the trigeminal nerve and decompression techniques for different types of vasculars. METHODS: The trigeminal nerve was sectioned into 5 zones. Zone 1, 2, 3, 4 was located at the rostral, caudal, ventral, and dorsal part of the nerve root entry zone (REZ) respectively, and zone 5 was located at the distal of the nerve root. This study contained 86 patients with trigeminal neuralgia underwent microvascular decompression. Every zone was exposed through preoperative imaging. During the operation, offending vessels were explored from zone 1 to zone 5, and different decompression techniques were used for different types of vessels. RESULTS: Through zone exploration, the sensitivity of preoperative imaging was 96.5% and specificity was 100%. Location of the neurovascular conflict was in the zone 1 in 53.5% of the patients, zone 2 in 32.6%, zone 3 in 45.3%, zone 4 in 29.1%, and zone 5 in 34.9%. In total, 2 zones were both involved in 59.3%, and 3 zones were involved in 18.6%. All offending arteries were moved away and interposed with Teflon sponge. Offending veins of 11 patients were too small to interpose, and coagulated and cut was adopted. The other offending veins were interposed with wet gelatin and Teflon sponge, respectively. CONCLUSIONS: Zone exploration is helpful in finding offending vessels and adequate decompression can be achieved by choosing different methods according to different types of offending vessels.

Management of vessels passing through the facial nerve in the treatment of hemifacial spasm.

BACKGROUND: In hemifacial spasm, it is extremely rare to find a vessel passing through the facial nerve. In this study, we present our experience of the surgical treatment of four such patients. METHODS: From January 2010 to Match 2015, we treated 2,576 hemifacial spasm patients with microvascular decompression in our department. Of these, four had an intraneural vessel. Intraoperative findings and treatment were recorded, and postoperative outcomes were analyzed. RESULTS: In three patients, the intraneural vessel was the anterior inferior cerebellar artery, which we wrapped with small pieces of wet gelatin and Teflon sponge. A small vein found in the fourth patient was treated with facial nerve combing. Complete decompression was achieved and abnormal muscle response disappeared. Three patients got an excellent result and one patient got a good result. One patient had postoperative facial paralysis, which improved over 10 months of follow-up. CONCLUSION: If an artery passes through the facial nerve, it can be decompressed by wrapping the vessel with wet gelatin and Teflon sponge. If a vein passes through the facial nerve, combing can be used. Intraoperative abnormal muscle response monitoring is very helpful in achieving complete decompression.

Nimodipine-mediated re-myelination after facial nerve crush injury in rats.

This study aimed to investigate the mechanism of nimodipine-mediated neural repair after facial nerve crush injury in rats. Adult Sprague-Dawley rats were divided into three groups: healthy controls, surgery alone, and surgery plus nimodipine. A facial nerve crush injury model was constructed. Immediately after surgery, the rats in the surgery plus nimodipine group were administered nimodipine, 6 mg/kg/day, for a variable numbers of days. The animals underwent electromyography (EMG) before surgery and at 3, 10, or 20 days after surgery. After sacrifice, nerve samples were stained with hematoxylin and eosin (H&E) and luxol fast blue. The EMG at 20 days revealed an apparent recovery of eletroconductivity, with the surgery plus nimodipine group having a higher amplitude and shorter latency time than the surgery only group. H&E staining showed that at 20 days, the rats treated with nimodipine had an obvious recovery of myelination and reduction in the number of infiltrating cells, suggesting less inflammation, compared with the rats in the surgery only group. Luxol fast blue staining was relatively even in the surgery plus nimodipine group, indicating a protective effect against injury-induced demyelination. Staining for S100 calcium-binding protein B (S-100ß) was not evident in the surgery alone group, but was evident in the surgery plus nimodipine group, indicating that nimodipine reversed the damage of the crush injury. After a facial nerve crush injury, treatment with nimodipine for 20 days reduced the nerve injury by mediating remyelination by Schwann cells. The protective effect of nimodipine may include a reduction of inflammation and an increase in calcium-binding S-100ß protein.

Delayed relief of hemifacial spasm after microvascular decompression: can it be avoided?

BACKGROUND: Although microvascular decompression (MVD) surgery has been widely accepted as an effective treatment for hemifacial spasm (HFS), delayed relief cases have been frequently reported. Therefore, the value of an immediate redo MVD should be discussed. METHODS: This study included 1,435 HFS patients who underwent MVD with intraoperative abnormal muscle response (AMR) monitoring from 2011 through 2013 at XinHua Hospital. These cases were analyzed retrospectively with emphasis on the postoperative outcomes and introaperative findings. RESULTS: After MVD, 1,384 HFS patients obtained relief immediately. The 51 unrelieved patients underwent AMR monitoring again the next day; this was positive in 48 and negative in 3 patients. These three patients with negative AMR obtained relief spontaneously within a week. Among the 48 positive patients, 31 and 11 were underwent redo MVD within a week and 5-22 months, respectively, and all achieved relief after the second operation. Of the six remainig patients, two obtained relief within 2 months and 4 remained unchanged in the up-to-3-year's follow-up period. In redo MVDs, insufficient decompression of the facial nerve accounted for the failure. Finally, in this database, the immediate postoperative cure rate was 96.4 %; with earlier redo MVD, the final cure rate could be increased to 99.9 %. CONCLUSIONS: Despite being a reasonable remedy for HFS in the hands of an experienced neurosurgeon, sometimes small vessels can be missed while managing the main offending arteries during MVDs, which might account for the delayed relief. Therefore, reexamination of the AMR is necessary for unimproved patients; if a positive result is recorded, an immediate redo MVD is suggested.

The mechanism of hemifacial spasm: a new understanding of the offending artery.

Although neurovascular confliction was believed to be the cause of hemifacial spasm (HFS), the mechanism of the disorder remains unclear to date. Current theories, merely focusing on the facial nerve, have failed to explain the clinical phenomenon of immediate relief following a successful microvascular decompression surgery (MVD). With the experience of thousands of microvascular decompression surgeries and preliminary investigations, we have learned that the offending artery may play a more important role than the effect of merely mechanical compression in the pathogenesis of the disease. We believe that the attrition of neurovascular interface is the essence of the etiology, and the substance of the disease is emersion of ectopic action potentials from the demyelinated facial nerve fibers, which were triggered by the sympathetic endings from the offending artery wall. In this paper, we put forward evidence to support this hypothesis, both logically and theoretically.