Microvascular Compression Research Articles

A case of cerebellopontine angle meningioma presenting as neurovascular compression syndrome of the 8th cranial nerve

A 54-year-old female patient presented with paroxysmal tinnitus and vertigo for 2 years, which have repeatedly occurred while rotating her neck, and lasted about 10 seconds. An anticonvulsant medication was prescribed with a diagnosis of microvascular compression syndrome on the 8th cranial nerve and audiovestibular evaluation and magnetic resonance imaging (MRI) scan were appointed a week later. In her next visit, she reported the disappearance of paroxysmal audiovestibular symptoms after medication. In the left ear, canal paresis and abnormal auditory brainstem response were observed. In MRI, a large meningioma in the cerebellopontine angle in the vicinity of the internal auditory canal orifice was detected, that was surgically resected by a neurosurgeon. After surgical removal of the tumor, she reported continuous dizziness due to vestibular nerve injury, but the paroxysmal attack of tinnitus and vertigo disappeared without anticonvulsant medication. This case suggests that an imaging study is mandatory when diagnosing microvascular compression syndrome on the 8th cranial nerve.

Progress in study on animal models of trigeminal neuralgia.

Trigeminal neuralgia is a manifestation of orofacial neuropathic pain disorder, always deemed to be an insurmountable peak in the field of pain research and treatment. The pain is recurrent, abrupt in onset and termination similar to an electric shock or described as shooting. A poor quality of life has been attributed to trigeminal neuralgia, as the paroxysms of pain may be triggered by innocuous stimuli on the face or inside the oral cavity, such as talking, washing face, chewing and brushing teeth in daily life. The pathogenesis of trigeminal neuralgia has not been fully elucidated, although the microvascular compression in the trigeminal root entry zone is generally considered to be involved in the emergence and progression of the pain disorder. In addition, orofacial neuropathic pain restricted to one or more divisions of the trigeminal nerve might be secondary to peripheral nerve injury. Based on current hypotheses regarding the potential causes, a variety of animal models have been designed to simulate the pathogenesis of trigeminal neuralgia, including models of compression applied to the trigeminal nerve root or trigeminal ganglion, chronic peripheral nerve injury, peripheral inflammatory pain and center-induced pain. However, it has not yet been possible to determine which model can be perfectly employed to explain the mechanisms. The selection of appropriate animal models is of great significance for the study of trigeminal neuralgia. Therefore, it is necessary to discuss the characteristics of the animal models in terms of animal strains, materials, operation methods and behavior observation, in order to gain insight into the research progress in animal models of trigeminal neuralgia. In the future, animal models that closely resemble the features of human trigeminal neuralgia pathogenesis need to be developed, with the aim of making valuable contributions to the relevant basic and translational medical research.

Internal Neurolysis for Trigeminal Neuralgia: Technical Nuances and a Single-Institution Experience

Trigeminal neuralgia is a facial pain syndrome most commonly caused by a neurovascular compression (NVC) of the trigeminal nerve. Microvascular decompression (MVD) is the most durable surgical treatment; however, patients without an NVC are not candidates for this procedure. Alternative treatments such as percutaneous rhizotomy and radiosurgery are effective but with higher recurrence rates. Internal neurolysis (IN) is a less frequently used procedure that aims to provide long-term relief to patients without NVC. We present the surgical techniques for IN developed at our institution. We also discuss the technical nuances related to nerve consistency and present a new classification based on these findings. We provide pain and numbness outcomes for our cohort of patients stratified by the extent of neurolysis and nerve consistency. Patients with medically intractable trigeminal neuralgia eligible for posterior fossa exploration are eligible for MVD and possible IN. If no NVC or a mild NVC is encountered, IN is performed. We have divided the procedure into 4 main steps: opening the outer connective sheath, fascicular dissection, inside-out dissection and the fascicular irrigation technique. Trigeminal nerve consistency has been classified into 3 main types: type 1 is soft and friable; type 2 is intermediate consistency and ideal for neurolysis; and type 3 is firm and presents a more challenging dissection. In the absence of microvascular compression, we advocate for a thorough neurolysis using the techniques described in our article.

A Multidisciplinary Approach in the Management of Hemifacial Spasm

Patients with hemifacial spasm are often misdiagnosed. This is a case report of a patient with eyelid myokymia who presents with worsening symptoms. Proper diagnosis of hemifacial spasm warrants an MRI revealing: microvascular compression displacing the right 7th cranial nerve at the root exit zone. The role of optometrists and different management options are discussed.

Glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor regulate the interaction between astrocytes and Schwann cells at the trigeminal root entry zone.

The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes. Its special anatomical and physiological structure renders it susceptible to nerve injury. The etiology of most primary trigeminal neuralgia is closely related to microvascular compression of the trigeminal root entry zone. This study aimed to develop an efficient in vitro model mimicking the glial environment of trigeminal root entry zone as a tool to investigate the effects of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor on the structural and functional integrity of trigeminal root entry zone and modulation of cellular interactions. Primary astrocytes and Schwann cells isolated from trigeminal root entry zone of postnatal rats were inoculated into a two-well silicon culture insert to mimic the trigeminal root entry zone microenvironment and treated with glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor. In monoculture, glial cell line-derived neurotrophic factor promoted the migration of Schwann cells, but it did not have effects on the migration of astrocytes. In the co-culture system, glial cell line-derived neurotrophic factor promoted the bidirectional migration of astrocytes and Schwann cells. Brain-derived neurotrophic factor markedly promoted the activation and migration of astrocytes. However, in the co-culture system, brain-derived neurotrophic factor inhibited the migration of astrocytes and Schwann cells to a certain degree. These findings suggest that glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor are involved in the regulation of the astrocyte-Schwann cell interaction in the co-culture system derived from the trigeminal root entry zone. This system can be used as a cell model to study the mechanism of glial dysregulation associated with trigeminal nerve injury and possible therapeutic interventions.

Microvascular Decompression for Hypoglossal Nerve Palsy Associated With Vertebral Artery: Case Report and Review of Literature

BACKGROUND AND IMPORTANCE: Hypoglossal nerve palsy is an infrequent condition that could be rarely caused by compression from nearing vasculature. Hypoglossal nerve palsy associated with vertebral artery (VA) is rarely reported. There are less than 15 cases of such conditions in the literature. CLINICAL PRESENTATION: We present a 17-year-old boy suffering from dysarthria, chewing disability, a tingling sensation, and deviation of the tongue to the right from 6 months ago. After a thorough examination, MRI was performed with clinical suspicion of hypoglossal nerve palsy, and the result showed an ectatic VA pressing against the right hypoglossal nerve. He underwent microvascular decompression surgery. On follow-up visits, he showed gradual improvement of symptoms. CONCLUSION: In cases of cranial nerve palsies, compression by adjacent vasculature should be considered as a differential diagnosis and microvascular compression should be considered as a safe definitive treatment.

Vascular Loop of Anterior Inferior Cerebellar Artery Causing Disabling Tinnitus, Vertigo, and Hearing Loss - A Review

The vascular anatomy of the anterior inferior cerebellar artery (AICA) is highly variable. In respect to the neurovascular relationship in the internal auditory canal (IAC), the AICA is intimately related with vestibulocochlear and facial nerve. Vascular loop of AICA, especially located in the IAC, is rare. This vascular loop of the IAC may result in the compression over the vestibulocochlear nerve. Microvascular compression of the eighth cranial nerve is an important cause for disabling tinnitus, vertigo, and hearing loss. Disabling tinnitus and vertigo due to intrameatal vascular loop of AICA compression, the vestibulocochlear nerve can be treated with help of drilling the internal acoustic meatus and separate the vascular loop from the vestibulocochlear nerve. The intrameatal AICA and vestibulocochlear nerve conflict produce specific pathological features and their surgical treatment is also invariably challenging. Decompression of the vestibulocochlear nerve by the opening of the IAC and transposition of the AICA is thought to be an effective treatment modality for radiologically confirmed cases with clinical presentations of unilateral sensorineural hearing loss and pulsatile tinnitus. The aim of this review article is to describe the details of vascular anatomy, etiopathology, clinical presentations, diagnosis, neurophysiology, and current treatment of the vascular loop of AICA in IAC which often pose challenge to the clinicians.

Inter-Observer Reliability of Fused Time-of-Flight MR Angiography and 3D Steady State Sequence versus 3D Contrast Enhanced Images in Evaluation of Neurovascular Compression

Purpose: Is to evaluate the accuracy of fused 3D time-of-flight (TOF) MR angiography and 3D Steady-State sequence (FIESTA) versus 3D contrast-enhanced T1 weighted images in evaluation of neurovascular compression via an inter-observer agreement protocol. Methods: Patients presented with trigeminal neuralgia, tinnitus, or facial hemispasm were examined using 3D-TOF-MRA, 3D-FIESTA, and 3D contrast-enhanced T1WI of the cerebellopontine angle to assess neurovascular compression. Two independent readers assessed the location, signal alteration, offending vascular structure, and grade of neurovascular compression using fused 3D-TOF-MRA and 3D-FIESTA versus contrast-enhanced T1 weighted images. The Kappa test for interobserver agreement was done. Results: The final study cohort consisted of 56 patients (42 females and 14 males) with a mean age of 38.25 ± 1.94. AICA was the offending vessel for 32 (57.1%) patients. The most common offending nerve was the trigeminal nerve in 26 patients, followed by facial/vestibulocochlear complex in 18 patients, and solely the 8th nerve in 12 patients. All three grades of compression were encountered in this study with percentages of 48.2% (27/56), 30.3% (17/56), and 21.4% (12/56) for grades I, II, III respectively. Fused TOF and steady-state images, and contrast-enhanced images showed perfect agreement for detection of the side of compression, the relation between nerve and vascular loop, offended neural segment, and offending vessel, while showing good agreement regarding the degree of compression. Conclusion: Fused TOF and steady-state images provide sufficient data to diagnose and grade microvascular compression syndromes comparable to contrast-enhanced images.

Vasküler loop sendromunda anterior inferior serebellar arterin çapı ve vasküler loop tipinin klinik bulgular ile ilişkisi: klinik radyoloji çalışması

Objective: Tinnitus and vertigo are common audiovestibular symptoms in the population. Many diseases can lead to the appearance of these symptoms, but the exact cause can often not be determined. It has been suggested that compression of the cranial nerves by vascular structures may be the cause of various clinical manifestations. This is known as microvascular compression syndrome. Some studies have stated that vascular compression syndromes are a serious pathology, while many studies have argued that vascular compression is only a radiological finding. We aimed to contribute to the literature on vascular compression syndrome and vascular loop types, which is still a controversial topic, and to determine the location of the diameter change in the anterior inferior cerebellar artery in the compression syndrome.
 Material and Method: Patients who underwent a Magnetic Resonance Imaging (MRI) examination of Temporal Bone due to a complaint of tinnitus or vertigo were retrospectively examined. The complaints of the patients, the diameters of the anterior inferior cerebellar artery (AICA) and the types of vascular loop were evaluated in the high resolution 3D fast imaging employing steady-state acquisition (FIESTA) sequence, according to the CHAVDA classification. The statistical relationship between the age of the patients, anterior inferior cerebellar artery diameters and vascular loop types and their clinical manifestations was investigated.
 Results: A total of 52 patients were enrolled in the study, of which 28 (53.8%) were male and 24 (46.2%) were female. The mean age of all patients was 47.58±18.734 years. The mean right AICA diameters of the patients were 1.10±0.206 mm, the mean left AICA diameter was 1.11±0.253 mm. Type 1 in 29 patients, type 2 in 12 patients, type 3 vascular loop in 4 patients were observed for the right side, while type 1 in 29 patient, type 2 in 12 patients, and type 3 in 7 patients were observed for the left side. There was no significant difference between vascular loop and tinnitus on the right and left (p=0.705; p=0.335, respectively). There was no significant difference between the right vascular loop and the left vascular loop and the vertigo (p>0.999; p=0.425, respectively). There was no significant difference between the right tinnitus, left tinnitus and vertigo in terms of the diameters of the right and left AICA in the patients (p=0.782; p=0.762; p=0.408; p=0.915, respectively).
 Conclusion: Vascular compression syndromes are clinical conditions that show symptoms over cranial nerves. Although the vascular loop syndromes originating from AICA have been discussed a lot recently, it is seen that there is no definite opinion. In our study, no association of AICA diameter and vascular loop type with clinical findings was found.

Flow cytometry analysis of immune and glial cells in a trigeminal neuralgia rat model

Microvascular compression of the trigeminal root entry zone (TREZ) is the main cause of most primary trigeminal neuralgia (TN), change of glial plasticity was previously studied in the TREZ of TN rat model induced by chronic compression. To better understand the role of astrocytes and immune cells in the TREZ, different cell markers including glial fibrillary acidic protein (GFAP), complement C3, S100A10, CD45, CD11b, glutamate-aspartate transporter (GLAST), Iba-1 and TMEM119 were used in the TN rat model by immunohistochemistry and flow cytometry. On the post operation day 28, GFAP/C3-positive A1 astrocytes and GFAP/S100A10-positive A2 astrocytes were activated in the TREZ after compression injury, there were no statistical differences in the ratios of A1/A2 astrocytes between the sham and TN groups. There was no significant difference in Iba-1-positive cells between the two groups. The ratios of infiltrating lymphocytes (CD45+CD11b−) (p = 0.0075) and infiltrating macrophages (CD45highCD11b+) (p = 0.0388) were significantly higher than those of the sham group. In conclusion, different subtypes A1/A2 astrocytes in the TREZ were activated after compression injury, infiltrating macrophages and lymphocytes increased, these neuroimmune cells in the TREZ may participate in the pathogenesis of TN rat model.

Acute effects of the different relaxation periods during passive intermittent static stretching on arterial stiffness.

To clarify whether the relaxation period during stretching affects the degree of elevated shear rate and the degree of reduction of arterial stiffness, we examined relaxation duration to build an adequate stretching protocol. In Experiment 1, the changes in cardiac output, the shear rate in the posterior tibial artery, and blood volume in the calf muscle were measured during recovery (0-60 s) from a single bout of one-legged passive calf stretching in 12 healthy young men. In Experiment 2, the effects of different relaxation periods (5-, 10-, 20-, and 60-s) of passive one-legged intermittent calf stretching (30-s × 6 sets) on the femoral-ankle pulse wave velocity (faPWV) as an index of peripheral arterial stiffness were identified in 17 healthy young men. As a result, the stretched leg's shear rate significantly increased from 0 to 10th s after stretching. The muscle blood volume in the stretched leg significantly reduced during stretching, and then significantly increased during the recovery period after stretching; however, cardiac output remained unchanged during stretching and recovery. Additionally, the reduction in faPWV from the pre-stretching value in the stretched leg was significantly larger in the protocol with 10-s and 20-s relaxation periods than that in the non-stretched leg, but this did not differ in the 5-s and 60-s relaxation periods. These findings suggest that the relaxation periods of intermittent static stretching that cause a high transient increase in shear rate (via reperfusion after microvascular compression by the stretched calf muscles) are effective to reduce arterial stiffness.

Hemimasticatory spasm. Own experience of using botulinum neuroprotein type A

Нemimasticatory spasm (HMS) is a rare disorder of the nervous system, in which there are unilateral, violent spasms of the masticatory muscles innervated by the motor portion of the trigeminal nerve. The causes of HMS remain largely unexplored, but microvascular compression is most likely. Anticonvulsants, surgical treatment and botulinum therapy can be applied for the treatment of HMS.We presented a clinical case of HMS in a 38-year-old woman who had been suffering from this disease for 18 years. The diagnosis of HMS was established only 10 years after the first visit to the doctor. Spasms could occur up to several hundred times a day with a duration up to 15 seconds. The magnetic resonance imaging allowed to exclude neurovascular conflict. Electroneuromyography revealed axonal lesion of the right trigeminal motor root and spontaneous activity in the right masseter muscle. Anticonvulsant treatment was ineffective. The patient received botulinum therapy with a good treatment result.

The thalamus in trigeminal neuralgia: structural and metabolic abnormalities, and influence on surgical response

BackgroundMedically-refractory trigeminal neuralgia (TN) can be treated successfully with operative intervention, but a significant proportion of patients are non-responders despite undergoing technically successful surgery. The thalamus is a key component of the trigeminal sensory pathway involved in transmitting facial pain, but the role of the thalamus in TN, and its influence on durability of pain relief after TN surgery, are relatively understudied. We aimed to test the hypothesis that variations in thalamic structure and metabolism are related to surgical non-response in TN.MethodsWe performed a longitudinal, peri-operative neuroimaging study of the thalamus in medically-refractory TN patients undergoing microvascular decompression or percutaneous balloon compression rhizotomy. Patients underwent structural MRI and MR spectroscopy scans pre-operatively and at 1-week following surgery, and were classified as responders or non-responders based on 1-year post-operative pain outcome. Thalamus volume, shape, and metabolite concentration (choline/creatine [Cho/Cr] and N-acetylaspartate/creatine [NAA/Cr]) were evaluated at baseline and 1-week, and compared between responders, non-responders, and healthy controls.ResultsTwenty healthy controls and 23 patients with medically-refractory TN treated surgically (17 responders, 6 non-responders) were included. Pre-operatively, TN patients as a group showed significantly larger thalamus volume contralateral to the side of facial pain. However, vertex-wise shape analysis showed significant contralateral thalamus volume reduction in non-responders compared to responders in an axially-oriented band spanning the outer thalamic circumference (peak p = 0.019). Further, while pre-operative thalamic metabolite concentrations did not differ between responders and non-responders, as early as 1-week after surgery, long-term non-responders showed a distinct decrease in contralateral thalamic Cho/Cr and NAA/Cr, irrespective of surgery type, which was not observed in responders.ConclusionsAtrophy of the contralateral thalamus is a consistent feature across patients with medically-refractory TN. Regional alterations in preoperative thalamic structure, and very early post-operative metabolic changes in the thalamus, both appear to influence the durability of pain relief after TN surgery.

Névralgies de la face

Facial nevralgias are rare but debilitating paroxystic or chronic pains. Consensual diagnostic criteria can help to establish the diagnosis, but misleading presentations exist. Trijeminal neuralgia has a pic incidence in women in theirs 1950s. Patients complains of lightning pain in the territory of a branch of the trijeminal nerve. The nerve lesion is most often secondary to a microvascular compression. The pain is triggered by a light sensation on a small area of the face. Pain are severe and sometimes confused with a dental affection. Pharmacotherapy is primarily based on carbamazepine/oxcarbazepine. Microvascular decompression is offered to patients not sufficiently controlled medically. Cluster headache is more common in young men. The pain last 30minutes to one hour is periorbital. Region and is accompanied by cranial autonomic symptoms. Cluster attacks have a circadian and circumannual rhythmicity. The pathyphysiology is nor fully understood. Intranasal/subcutaneous triptan or high concentration oxygen inhalation are the mainstay of acute treatment. Prevention of cluster recurrence is based on verapamil or lithium administration. Postherpetic neuralgia is defined of the persistence of pain 3 months after a herpes zoster rash. The prevalence of the disease increased with age. It presents as a chronic neuropathic pain that must be treated with appropriate medications. Other facial nevralgias have been described such as occipital or glossopharyngeal nevralgia. Due to their significant impact on quality of life, awareness of the entities is critical an early and to avoid misdiagnosis.

Magnetic resonance neurography in the management of trigeminal neuralgia: a cohort study of 55 patients

To explore the usefulness of magnetic resonance neurography (MRN) in the diagnosis and management of trigeminal neuralgia (TN). In total, 55 patients clinically diagnosed with TN were imaged with 3.0-T magnetic resonance imaging. Images were reconstructed to show the full course of the trigeminal nerve. Clinical findings included mean duration of symptoms (41.99 months) and mean visual analog scale pain intensity (5.98). Final diagnoses were microvascular compression (19), inflammation (21), microvascular compression with inflammation (5), normal (5), tumor (1), peripheral nerve injury (2), and multiple sclerosis (2). MRN had substantial impact on diagnosis and treatment in 56.4% of cases. A total of 33 patients underwent intervention for pain. MRN had substantial impact on 54.5% of the treated patients. The correlation between MRN results and intervention response was excellent in 19 patients (57.6%) and moderate in 14 (42.4%). Pain was reduced after surgery or interventional procedure in most cases (75.8%). MRN is suitable for the diagnosis of clinical TN with beneficial impact on diagnosis and clinical management and moderate-to-excellent correlation with intervention response. Diagnosis of TN should focus not only on microvascular compression but also on the conditions of the peripheral branches of the trigeminal nerve.

Clinical perspectives of anterior inferior cerebellar artery: a review

<p class="abstract">The anterior inferior cerebellar artery arises at the cerebellopontine angle (CPA), usually from the lower one third of the basilar artery. However, the vascular anatomy of the anterior inferior cerebellar artery (AICA) is highly variable. In respect to the neurovascular relationship in the internal auditory canal (IAC), the AICA is intimately related with vestibulocochlear and facial nerve. Microvascular compression of the vestibulocochlear nerve by AICA is an important etiology for tinnitus, hearing loss and vertigo. The vascular loop or aneurysm of the AICA will compress the vestibulocochlear nerve in the internal auditory canal. The AICA loop should be separated from the vestibulocochlear nerve. Magnetic resonance angiography (MRA) is helpful to reveal the vascular pathology of the AICA and confirm the causes for disabling otological symptoms. After confirmation of the vascular pathology of AICA, surgery is usually planned. The intrameatal AICA and vestibulocochlear nerve conflict produce specific pathological features and their surgical treatment is also invariably challenging. The objective of this review article is to discuss the details of vascular anatomy, etiopathology, clinical presentations, diagnosis, neurophysiology and current treatment of the vascular anomalies of AICA in IAC which often pose challenge to the clinicians.</p>

Abstract 14381: Patient-specific Fluid Structure Interaction Simulations of Anomalous Origins of Right Coronary Arteries in Adults Correlate With Measured Instantaneous Wave-free Ratio

Introduction: Anomalous coronaries are associated with ischemia and sudden death, but the recommendation to undergo surgery is often uncertain, especially for asymptomatic individuals with an anomalous aortic origin of the right coronary artery (AAORCA). For risk stratification, dobutamine-stress instantaneous wave-free ratio (iFR) is increasingly used. Meanwhile, advances in fluid-structure interaction (FSI) modeling have enabled the simultaneous simulation of blood flow and tissue deformation that may elucidate the mechanism of ischemia in AAORCA. Hypothesis: We hypothesized that the iFR simulated by patient-specific FSI models of AAORCA correlates with the measured iFR at rest and dobutamine-stress, and the hemodynamic mechanism is mainly due to the intramural geometry. Methods: Using the Simvascular software package, we constructed 6 FSI models of the AAORCA which encompassed the aortic root, the intramural course (if present), and coronary outlets coupled to lumped parameter networks that included the dynamic microvascular compression. Each model was customized to the patients’ computed tomography angiography, vitals, and cardiac output. Results: All 6 AAORCAs had an interarterial course, and all but one had an intramural course. Measured iFRs ranged from 0.98 to 0.95 at rest, and from 0.95 to 0.80 with dobutamine-stress. The FSI model yielded realistic pressures and flows waveforms (Fig. 1). After we tuned the resistances to achieve flow rates at stress to be triple those at rest, the FSI simulations adequately matched the measured iFR (r = 0.85, RMSE = 0.04). Conclusions: Patient-specific FSI modeling is a promising non-invasive tool to assess the hemodynamic effects of AAORCA including the intramural course. However, the iFR’s sensitivity to the flow rate suggests a future role for quantitative stress-perfusion imaging to augment the iFR measurements for AAOCA risk stratification.

Brain‐derived neurotrophic factor and Glial cell line‐derived neurotrophic factor expressions in the trigeminal root entry zone and trigeminal ganglion neurons of a trigeminal neuralgia rat model

Microvascular compression on the trigeminal root entry zone (TREZ) is the main etiology of trigeminal neuralgia (TN) patients. To investigate brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in the trigeminal ganglion (TG) and TREZ, immunofluorescence staining and Western blot were used in a rat TN model. Both BDNF and GDNF were observed in the TG neurons and TREZ. The expression of the BDNF dimer in the TG was increased in the TN group, while GDNF expression was decreased after compression injury. The BDNF dimer/pro-BDNF ratio in the TREZ of the TN group was higher than that in the sham group, but the GDNF expression in the TREZ was significantly lower than that in the sham group. These results suggested that compression injury in the TREZ of rats induced dynamic changes in BDNF and GDNF in both the TG and TREZ, and these changes are involved in the nociceptive transmission of the TN animal model.

Application of complete endoscopic technique in microvascular decompression related tovertebrobasilar artery compression

Objective: To study the operative method, special technique and curative effect of complete neuroendoscopic microvascular decompression(MVD) related to vertebrobasilar artery compression. Methods: Thirteen patients with functional cranial nerve disease caused by vertebrobasilar artery as direct or indirect responsible vessel accepted complete endoscopic MVD, including 11 patients with hemifacial spasm and 2 patients with trigeminal neuralgia. The procedure and curative effect of endoscopic surgery were analyzed retrospectively. Results: All procedures of complete neuroendoscopic MVD were successfully completed.Intraoperative observation by endoscope showed that 6 cases were oppressed directly by vertebral artery, 2 cases were oppressed directly by basilar artery, 5 cases were combined oppressed by displaced basilar artery and other vessels (1 case was superior cerebellar artery and 4 cases were anterior inferior cerebellar artery). During the operation, Teflon sheets was placed directly into the compression point in 2 cases, the "Pre-placed" technique was used to place Teflon sheets in 7 cases, and the "Set up bridge" technique was used to place Teflon sheets in 4 cases. Follow-up for 8-38 months,the symptoms disappeared completely in 12 cases and improved in 1 case. No deaths and severe complications occurred, such as postoperative bleeding, cerebellar infarction and intracranial infection. Conclusion: MVD related to vertebrobasilar artery compression can be performed by complete neuroendoscopic technique, which can achieve sufficient decompression effect and curative effect.Flexible use of the special technology of placing Teflon sheets by single-hand under endoscope, such as the "Pre-placed" and "Set up bridge" technique, is an important technical guarantee for the successful completion of endoscopic MVD.

Immunohistochemical analysis of histone H3 acetylation in the trigeminal root entry zone in an animal model of trigeminal neuralgia.

The trigeminal root entry zone (TREZ) is a transitional zone between the central nervous system (CNS) and peripheral nervous system (PNS), adjacent to the brainstem. Microvascular compression of the TREZ has been considered to be the primary etiology in most cases of trigeminal neuralgia (TN), but whether epigenetic regulation is involved in the pathogenesis of TN is still unclear. Therefore, this study was designed to investigate the epigenetic regulation of histone H3 acetylation in the TREZ in an animal model of TN. An animal model of TN was established, and adult male Sprague-Dawley rats were randomly assigned to a TN group with trigeminal nerve root compression, sham operation group, TN+HDACi group (TN plus selective histone deacetylase inhibitor injection into the TREZ), or TN+Veh group (TN plus vehicle injection into the TREZ). To measure the length of the central portion of the TREZ from the junction of the trigeminal nerve root entering the pons to the interface of the dome-shaped CNS-PNS transitional zone, immunofluorescent staining of glia and glial nuclei was performed using glial fibrillary acidic protein (GFAP) antibody and DAPI, respectively. To investigate the acetylation of histone H3 within the TREZ in a TN animal model group and a sham operation group, localization of histone H3K9, H3K18, and H3K27 acetylation was examined via immunohistochemical staining methods. Measurements of the CNS-PNS transitional zone in the TREZ revealed that the average length from the junction of the trigeminal nerve root connecting the pons to the glial fringe of the TREZ in the TN group was longer than that in the sham operation group (p < 0.05) and that the interface gradually migrated distally. Cells that stained positive for acetylated histone H3K9, H3K18, and H3K27 were distributed around both sides of the border of the CNS-PNS junction in the TREZ. The ratio of immunoreactive H3K9-, H3K18- and H3K27-positive cells in the TN group was obviously higher than that in the sham operation group on postoperative days 7, 14, 21, and 28 (p < 0.05). These results suggested that chronic compression of the trigeminal nerve root may be involved in the pathogenesis of TN in an animal model by influencing the plasticity of the CNS-PNS transitional zone and the level of histone acetylation in the TREZ.