Cranial Nerve Function Research Articles

Sympathetic hyperactivity, hypertension, and tachycardia induced by stimulation of the ponto-medullary junction in humans

ObjectiveThe purpose of this study is to investigate changes in autonomic activities and systemic circulation generated by surgical manipulation or electrical stimulation to the human brain stem. MethodsWe constructed a system that simultaneously recorded microsurgical field videos and heart rate variability (HRV) that represent autonomic activities. In 20 brain stem surgeries recorded, HRV features and sites of surgical manipulation were analyzed in 19 hypertensive epochs, defined as the periods with transient increases in the blood pressure. We analyzed the period during electrical stimulation to the ponto-medullary junction, performed for the purpose of monitoring a cranial nerve function. ResultsIn the hypertensive epoch, HRV analysis showed that sympathetic activity predominated over the parasympathetic activity. The hypertensive epoch was more associated with surgical manipulation of the area in the caudal pons or the rostral medulla oblongata compared to controls. During the period of electrical stimulation, there were significant increases in blood pressures and heart rates, accompanied by sympathetic overdrive. ConclusionsOur results provide physiological evidence that there is an important autonomic center located adjacent to the ponto-medullary junction. SignificanceA large study would reveal a candidate target of neuromodulation for disorders with autonomic imbalances such as drug-resistant hypertension.

Perioperative Nimodipine to Improve Cranial Nerve Function: A Systematic Review and Meta-Analysis.

Nimodipine has emerged as a promising strategy for protection of cranial nerves following vestibular schwannoma (VS) resections. Our goal was to conduct a comprehensive analysis of clinical studies to determine the therapeutic efficacy of nimodipine in improving facial nerve and cochlear nerve function. We searched PubMed, Scopus, Cochrane Clinical Trial Registry, Clinicaltrials.gov, World Health Organization's International Clinical Trials Registry Platform, and EU Clinical Trials Registry to identify clinical studies up to May 11, 2020. We included studies evaluating perioperative administration of nimodipine as a strategy to prevent or treat facial nerve or cochlear nerve dysfunction following VS resections. Primary outcomes included preservation or recovery of House-Brackman scale for facial nerve function and Hearing and Equilibrium Guidelines for cochlear nerve function at the latest follow-up visit. Secondary outcomes included adverse events and administration strategies of nimodipine. Nine studies (603 patients) met inclusion, of which seven studies (559 patients) were included in the quantitative analysis. Overall, nimodipine significantly increased the odds of cranial nerve recovery compared with controls (odds ratio [OR] 2.87, 95% confidence intervals [CI] [2.08, 3.95]; I2 = 0%). Subgroup analysis demonstrated that nimodipine was only effective for cochlear nerve preservation (OR 2.78, 95% CI [1.74, 4.45]; I2 = 0%), but not for facial nerve function (OR 4.54, 95% CI [0.25, 82.42]; I2 = 33%). Although there is evidence supporting the perioperative role of nimodipine for VS resections, more studies are warranted to help clarify the effects of nimodipine therapy on cranial nerve preservation.

Trigger electromyography in endoscopic transnasal surgery of skull base tumors

Introduction . The development of minimally invasive technologies in recent decades has expanded the indications for the use of endoscopic transnasal transsphenoidal approaches in surgery of skull base tumors. It became possible to perform surgical interventions aimed at removing tumors of the base of the skull that spread to the area of the passage of cranial nerves (cavernous sinus, clival area, cerebello-pontine angle), which is associated with the risk of damage to certain cranial nerves. The study objective is to evaluate the effectiveness of trigger electromyography in providing anatomical and functional preservation of cranial nerves during endoscopic endonasal transsphenoidal removal of skull base tumors. Materials and methods . The study is based on statistical analysis and comparison of the results of surgical treatment of two groups of patients with various tumors of the base of the skull: the main group (30 patients with using trigger electromyography to identify cranial nerves intraoperatively) and the control group (43 patients without using this method). The effectiveness and safety of using the method of intraoperative identification of cranial nerves was evaluated based on a comparison of basic characteristics, treatment outcomes, and factors potentially affecting them. Results . Fifty-seven (57) cranial nerves were identified intraoperatively in the main group. The frequency of radical removal was 1.6 times higher in the main group (70 % vs 44.2 %, p = 0.03). When analyzing the dynamics of the state of motor cranial nerves after surgery in the main and control groups, it was shown that negative dynamics prevailed in the control group — 37.2 % vs 13.3 % (p = 0.03), and positive dynamics prevailed in the main group (37.3 % vs 13.9 %), 2.8 times (p = 0.08). Conclusion . The obtained data indicate that the use of the intraoperative identification method in endoscopic transnasal surgery of skull base tumors can positively affect the radical removal of tumors and the preservation of cranial nerve function in the postoperative period.

Триггерная электромиография в эндоскопической трансназальной хирургии опухолей основания черепа

Preserving anatomical integrity and functions of cranial nerves when removing skull base tumors is one of the significant problems of endoscopic endonasal surgery. For this purpose, it is possible to use intraoperative mapping and cranial nerves identification. The aim of the study was to evaluatе the effectiveness of trigger electromyography (T-EMG) used to prevent iatrogenic damage to the cranial nerves intraoperatively. Twenty-one patients with different skull base tumors were included in the study. Mapping and identification of cranial nerves were carried out during tumor excision, using endoscopic endonasal access. Surgeries were performed on large skull-based chordomas, neuromas of the trigeminal nerve in the cavernous sinus region, pituitary adenomas, meningiomas in the clivus and a skull-based cholesteatoma. Mapping and identification of cranial nerves were carried out using electromyography in trigger mode using bipolar and monopolar electrodes. Functional activity of cranial nerves was evaluated both before and after the operation. The effectiveness of the technique was compared with that of the control group (41 patients). In the course of surgical interventions using T-EMG in the main group of patients, 40 nerves were analyzed. In the course of the study, III, V, VI, VII, XII cranial nerves were identified intraoperatively. In 4 patients in the main group and in 13 patients in the control group, a postoperative deficit of cranial nerves was observed. We did not receive statistically reliable data that the intraoperative identification of cranial nerves using T-EMG reduces the frequency of postoperative complications in the form of a deficiency of cranial nerves (p=0.11), but the ratio of chances (0.26) testifies in favor of rarely occurring complications in main group. Trigger electromyography allows us to estimate the functional state of the cranial nerves during endoscopic endonasal operations. The method of using T-EMG is promising and requires further research.

Far Lateral Transcondylar Transtubercular Approach for Microsurgical Resection of Foramen Magnum Meningioma: Operative Video and Technical Nuances.

Surgical access to the ventral foramen magnum remains a technical challenge. With large lesions in this region compressing the brainstem and distorting the regional neurovascular relationships, formulating a surgical plan and its appropriate execution have crucial importance in achieving favorable outcomes. While the endoscopic endonasal approaches have gained increasing attention to access the clivus and the ventral brainstem, foramen magnum meningiomas are still preferred to be removed via an approach that obviates a trajectory through the nasopharyngeal mucosa. Therefore, the far lateral approach remains one of the most practical approaches for these challenging lesions. This operative video demonstrates the use of the far lateral transcondylar transtubercular approach to remove a large meningioma in the ventral foramen magnum in a 63-year-old male with progressive cervical myelopathy, presenting as spastic quadriparesis without any cranial nerve abnormality. Using a right-sided far lateral transcondylar transtubercular approach, the meningioma was exposed within the cerebellomedullary gutter engulfing the vertebral artery and distorting the course of the adjacent cranial nerves. Using the different corridors identified between the vertebral artery, spinal accessory, vagus, and hypoglossal nerves, multiple angles of attacks to the tumor were established and utilized to resect the lesion. A gross total resection was achieved and the patient was neurologically intact without any neurological deficits. This video demonstrates the importance of understanding the intricacies of neurovascular anatomy of the cervicomedullary region (i.e., the various triangles formed between these structures), and the effective use of these corridors to safely and efficiently remove a challenging ventral foramen magnum meningioma with neurovascular involvement, while preserving cranial nerve function. The surgical technique and nuances are described in a step-by-step fashion in this illustrative operative video. The link to the video can be found at: https://youtu.be/s1dFhuaRSt8 .

Neurodevelopmental Outcome in Extremely Low Birth Weight Infants at 2-3 Years of Age.

Background and objectives: The aims of this study were to examine the relationship between neurological outcomes at 3- and 6-months corrected age with the neurodevelopmental outcome at 3 years of age; to identify the perinatal/neonatal risk factors for poor neurodevelopmental outcomes at 3 years of age. Materials and methods: In our single-centre longitudinal cohort study, of the 73 consecutive infants admitted to our Neonatal Intensive Care Unit (NICU), 49 infants (80%) received both Hammersmith Infant Neurological Examination (HINE) at 3- and 6-months corrected age and Bayley–III neurodevelopmental assessment at 2–3 years chronological age. At 3 months follow up, 8.2% had suboptimal scores (below 10th percentile) on the HINE. At 6 months follow up, 4.1% had suboptimal scores (below 10th percentile) on the HINE. The means(±SD) for Bayley-III cognitive, language, and motor subscales were (96.3 ± 9.8), (99.9 ± 11.9), (93.2 ± 9.9). Results: At 3 months corrected age, higher total HINE scores and subscores for function of cranial nerves, posture, tone, were associated with better cognitive scores while poorer scores for function of cranial nerves, posture, movements, tone, and total HINE score were associated with lower motor scores. Infants with a HINE subscore of function of cranial nerves in the suboptimal range have three times higher odds of having a motor delay. Infants with a HINE subscore of function of cranial nerves in the suboptimal range have more than two times higher odds of having a language delay. At 6 months corrected age, poorer scores for function of cranial nerves, movements, tone, reflexes, and total HINE score were associated with worse Bayley-III motor scores whilst infants who have a total HINE score and a subscore of reflexes in the suboptimal range have four and seven times, respectively, higher odds of having a motor delay. Conclusions: Early identification of infants at risk for adverse long-term outcomes is essential in introducing early intervention therapies for optimizing neurodevelopmental outcomes.

Midline Suboccipital Subtonsillar Approach in Semisitting Position for Resection of Jugular Tubercle Meningioma: 2-Dimensional Operative Video.

We present a case of a large jugular tubercle meningioma that was removed through a midline suboccipital subtonsillar approach in semisitting position. The patient is a 49-year-old woman with chronic, medication-resistant cephalgias but devoid of any subjective focal neurological deficit. On magnetic resonance imaging (MRI), an extra-axial lesion, originating from the left jugular tubercle was discovered. There was significant obliteration of the peripontine cisternal space, and compression of the adjacent pontomedullary junction; the lesion also extended into the left jugular foramen.On physical exam, an absent gag reflex was noted on the left, as well as a moderate deviation of the uvula to the contralateral side (partial Vernet's syndrome).A gross-total resection was achieved, histopathology confirmed a World Health Organization (WHO) grade I angiomatous meningioma with a low-proliferation index. The patient was discharged home 4 days after surgery with intact function of the lower cranial nerves (CN) following immediate and complete resolution of the preexisting partial CNs IX and X deficits. At 2-year follow-up, there was no indication of intradural residual or recurrence.In summary, the midline suboccipital subtonsillar approach is a simple and effective tool with limited morbidity in the armamentarium for the microsurgical management of pathologies residing in the posterior cranial fossa or the craniocervical junction.Major limitations exist for lesions extending above the internal acoustic canal or those of fibrous consistence featuring widespread adhesion to the ventral brainstem or vascular encasement. Provided the necessary anesthesiological precautions and intraoperative procedures the semisitting position is safe and effective. The link to the video can be found at: https://youtu.be/bbVXagwhDCo .

Clinical Benefit of Crenolanib, with or without Salvage Chemotherapy, in Multiply Relapsed, FLT3 Mutant AML Patients after Prior Treatment with Gilteritinib

Clinical Benefit of Crenolanib, with or without Salvage Chemotherapy, in Multiply Relapsed, FLT3 Mutant AML Patients after Prior Treatment with Gilteritinib

Multimodal outcome assessment after surgery for brainstem cavernous malformations.

The object of this study was to assess outcome after surgery for brainstem cavernous malformations (BSCMs) using functional, health-related quality of life (HRQOL), and psychological surveys to analyze the interrelation of these measurements, and to compare HRQOL and anxiety and depression scores with those in a healthy population. The authors performed a cross-sectional outcome study of all patients surgically treated for BSCM in their department between January 1, 2003, and December 31, 2019. They assessed functional outcome via the modified Rankin Scale (mRS), health-related quality of life (HRQOL) via the SF-36 and 9-item Life Satisfaction Questionnaire (LISAT-9), cranial nerve and brainstem function using a questionnaire, symptom-based psychological outcome via the Hospital Anxiety and Depression Scale (HADS), and timepoint of a return to previous employment. They analyzed the correlation between absolute (mRS score ≤ 2) and relative (postoperative deterioration in initial mRS score) outcome endpoints and the interrelation of the outcome measures and performed a comparison of HRQOL and HADS scores with findings in a healthy population. Seventy-four patients were eligible for inclusion in the study. HRQOL was impaired after surgery for BSCM compared to that in a healthy population. This impairment was substantial in patients with an unfavorable functional outcome (mRS > 2) but was also present in those with a favorable outcome (mRS ≤ 2) in selected domains. Psychological impairment was negligible in patients with a favorable outcome and grave in those with an unfavorable outcome. LISAT-9 results revealed that brainstem and cranial nerve symptoms reduce satisfaction mainly in self-care abilities for both unfavorable and favorable outcome patients. Among the brainstem and cranial nerve symptoms, balance impairment showed the most significant impact on HRQOL. Absolute outcome endpoints were superior to relative outcome endpoints in reflecting impairment in HRQOL after surgery. The study data can improve patient counseling and decision-making in BSCM treatment and may function as a benchmark. The authors report outcomes after BSCM surgery in high detail, emphasizing the specific impact of cranial nerve and brainstem symptoms on HRQOL. When reporting BSCM surgery outcome, absolute outcome endpoints should be applied.

An Update on Idiopathic Hypertrophic Cranial Pachymeningitis for the Headache Practitioner.

We aim to review idiopathic hypertrophic cranial pachymeninigitis (IHCP), describe common head pain patterns and features associated with the disorder, suggest potential classification of head pain syndromes based on the recently published International Classification of Headache Disorders-3, explore pathophysiology found to be associated with cases of IHCP, and indicate common treatment for the disorder. It is suggested that a subset of IHCP is an IgG4-related autoimmune disorder. Patients with IHCP were found to have elevated cerebrospinal fluid (CSF) protein and lymphocytic pleocytosis. Corticosteroids are a mainstay of treatment. Other immunosuppressive agents and steroid sparing agents as add-on therapy may have utility in the treatment of cases refractory to corticosteroids alone. Clinical manifestations of IHCP depend upon the location of the inflammatory lesions and compression of the adjacent nervous system structures. Headache and loss of cranial nerve function were the most common presenting features of hypertrophic cranial pachymeninigitis. Several headache diagnoses may result from IHCP. Gadolinium-enhanced MRI is the standard imaging modality for diagnosing. Although the pathophysiology is poorly understood, many cases of hypertrophic pachymeninigitis (HP) are thought to be closely related to inflammatory disorders. Cases of HP previously thought to be idiopathic may have IgG4 pathophysiology. CSF and serological studies are helpful. Treatment involves immunosuppressive agents. Advancement in neuroimaging, assays, tests, and further delineation of inflammatory disorders affecting the nervous system may provide further insight to the etiology of cases of HP previously considered and diagnosed as idiopathic.

The Role of 3D Tractography in Skull Base Surgery: Technological Advances, Feasibility, and Early Clinical Assessment with Anterior Skull Base Meningiomas.

Objective The aim of this study is to determine feasibility of incorporating three-dimensional (3D) tractography into routine skull base surgery planning and analyze our early clinical experience in a subset of anterior cranial base meningiomas (ACM). Methods Ninety-nine skull base endonasal and transcranial procedures were planned in 94 patients and retrospectively reviewed with a further analysis of the ACM subset. Main Outcome Measures (1) Automated generation of 3D tractography; (2) co-registration 3D tractography with computed tomography (CT), CT angiography (CTA), and magnetic resonance imaging (MRI); and (3) demonstration of real-time manipulation of 3D tractography intraoperatively. ACM subset: (1) pre- and postoperative cranial nerve function, (2) qualitative assessment of white matter tract preservation, and (3) frontal lobe fluid-attenuated inversion recovery (FLAIR) signal abnormality. Results Automated 3D tractography, with MRI, CT, and CTA overlay, was produced in all cases and was available intraoperatively. ACM subset : 8 (44%) procedures were performed via a ventral endoscopic endonasal approach (EEA) corridor and 12 (56%) via a dorsal anteromedial (DAM) transcranial corridor. Four cases (olfactory groove meningiomas) were managed with a combined, staged approach using ventral EEA and dorsal transcranial corridors. Average tumor volume reduction was 90.3 ± 15.0. Average FLAIR signal change was -30.9% ± 58.6. 11/12 (92%) patients (DAM subgroup) demonstrated preservation of, or improvement in, inferior fronto-occipital fasciculus volume. Functional cranial nerve recovery was 89% (all cases). Conclusion It is feasible to incorporate 3D tractography into the skull base surgical armamentarium. The utility of this tool in improving outcomes will require further study.

“Interdural” Surgical Strategy for Lower Cranial Nerve Neurinomas—A Report of 14 Cases

We describe the dural relationships and its surgical implications for large lower cranial nerve (CN) neurinomas. The study is based on surgical experience with 14 cases. During the period January 2014 to December 2019, 14 consecutive cases with large lower CN neurinomas were surgically treated with the aim of radical tumor resection. There were 9 males and 5 females, ranging in age from 17 to 65 years. All patients were operated in a single stage. The principal surgical observation was that the entire extent of tumor, which included intracranial, jugular fossa, and extracranial components, was within the "dural" confines and the tumor adjoining critical neural and vascular structures was displaced around the dome of the tumor. Radical surgical resection was achieved in all cases. During the follow-up period that ranged from 3 to 71 months (average 32 months), no symptomatic recurrence was observed and no patient needed reoperation. At the time of last clinical follow-up, the lower CN function in all patients was better than at the time of presentation. The "dural" cover of the lower CN neurinomas forms a strong and reliable plane of compartmentalization and allows safe tumor resection.

The Role of Serotonin in Singultus: A Review.

The use of dopamine receptor blockers for chronic singultus treatment is based—at least partially—on circular thinking: chlorpromazine is FDA-approved for hiccups, chlorpromazine is a neuroleptic, neuroleptics are dopamine receptor blockers, and therefore hiccup is due to dopaminergic dysfunction. Chlorpromazine interacts with high affinity with a multitude of receptors and ion channels. This promiscuity is the basis for many of the therapeutic effects and adverse drug reactions of this drug. While an involvement of dopamine is certain, it is by no means clear that dopaminergic dysfunction is the hallmark of singultus. The common denominator of most remedies for transient hiccup is their ability to activate the vagus nerve. Both afferent and efferent vagal activity and the central integration of the Xth cranial nerve function are modulated, inter alia, via serotonergic mechanisms; beneficial (therapeutic) effects for hiccup are to be expected from serotonin (5-HT) receptor subtype ligands that enhance vagal activity. Taken together, it appears that the ability to increase vagus output is mainly associated with 5-HT1A, 5-HT3, and 5-HT7 agonists and with 5-HT2C antagonists. The plausibility of the serotonergic singultus hypothesis is examined against available pharmacokinetic, pharmacodynamic, and clinical data for a number of drugs.

Acute leukoencephalopathy in an adult

A 35-year-old unmarried man living alone was brought to the emergency department with acute abdominal pain mainly in the epigastric region. He could not provide any detailed history regarding his...

Petroclival meningiomas: the risk of post-operative cranial nerve deficits among different surgical approaches-a systematic review and meta-analysis.

The surgical resection of petroclival meningiomas (PCMs) remains a challenge. Both the relationship with neurovascular structures and the deep location of the tumor can affect the extent of resection and the rate of post-operative morbidity. The authors performed a systematic review and meta-analysis of the literature examining the rate of new cranial nerve (CN) deficits after resection of PCM. A systematic search of two databases was performed for studies published between 1990 and 2018. Random-effect meta-analysis was used to pool the rate of post-operative CN deficits, mortality rate, and rate of radical resection. We included twelve studies and 334 patients harboring PCM. The overall rate of complete resection was 68% (95% CI 57.9-78.2%; p < 0.01; I2= 83%). The rate of early and late post-operative CN deficits was the following: 3.8 and 2.7% (III CN), 6.6 and 3% (IV), 7.3 and 5.5% (V CN), 8 and 3.6% (VI CN), 8.9 and 8.9%% (VIII), and 4 and 2.7% (IX-XI CNs) (I2= 0%, and p < 0.01 for all analyses). The risk of post-operative deficit of the IV CN was higher among the petrosal group (7.6%; I2= 0% vs 2.1%; I2= 0%), whereas the impairment of VII CN function was higher among retrosigmoid group (16.6%; I2= 64.6% vs 11.4%; I2= 52.8%), but it was transient in the majority of cases. This systematic review and meta-analysis provides a detailed overview of post-operative CN deficits ensuing surgical resection of PCMs. These findings should be acknowledged when counseling patients with PCMs regarding the more appropriate approach for their tumor.

Transvenous Onyx Embolization of Carotid-Cavernous Fistulas: Mid- and Long-Term Outcomes.

Objective Endovascular treatment of carotid-cavernous fistulas (CCFs) has been consistently shown to give excellent results and is currently the mainstay of treatment of these complex vascular pathologies. Onyx is currently the most widely used agent, but there has been concern over high rates of cranial nerve (CN) deficits seen in patients with CCF treated with Onyx and paucity of data on long-term outcomes. Methods This is a retrospective analysis of patients who underwent transvenous Onyx embolization between 2011 and 2018. The data collected included demographics, comorbidities, presenting symptoms, CCF morphology, degree of obliteration, procedure-related complications, clinical outcomes, and follow-up. Results A total of seven patients (five females) were included. The median age was 66 years (range: 15-79 years). Median duration of symptoms before treatment was 4 weeks (range: 1-24 weeks). There were three direct and four indirect CCFs. Barrow classification is as follows: A-3; B-3; C-0; and D-1. Immediate complete occlusion was achieved in all cases. There was also one case of immediate postoperative change in CN function (new partial CN VI deficit) that resolved completely at 1-month follow-up. The mean length of stay was 3 days (±2). The preoperative extraocular movement CN deficits had the following outcomes: three resolved; two improved; and one persisted. Proptosis, chemosis, conjunctival injection, and tinnitus were resolved in all patients. The median follow-up was 34 months (range: 10-91 months). Conclusion Transvenous Onyx embolization is a safe and effective treatment of CCFs when technical aspects to reduce complications are performed diligently. Our technique demonstrates safety of the Onyx as a stand-alone embolization for the treatment of CCF.

Integrating 3D Animated Videos in Case‐Based Study of Cranial Nerve Pathology

The structures and functions of cranial nerves are essential topics in the gross anatomical study of the head and neck. Cranial nerves with complicated pathways carry multiple modalities and exhibit several symptoms when injured. Conventionally, the course and branching patterns of these nerves are taught using two‐dimensional resources with limited perspective and depth. Three‐dimensional anatomical applications allow us to map the pathways of cranial nerves toward their peripheral targets to reinforce understanding of complex spatial relationships. We created a series of animated videos through the 3D4Medical Complete Anatomy application to demonstrate the courses and modalities of three challenging cranial nerves (CN), VII, IX and X. These videos cater to flipped learning, a student‐centered pedagogical approach. Here we describe the methodology and effectiveness of integrating 3D‐animated videos into a flipped classroom paradigm to enhance understanding of cranial nerve pathways, functions, and pathologies. Forty students participated in two flipped sessions (20 students per session) administered as a series of clinical cases studies. Students were expected to watch the cranial nerve animation videos prior to the session. Class time was devoted to small‐group discussion and application of knowledge through case‐based learning and formative assessments. Each of the answer choices were reviewed following discussion of the case. Individual student performances (n = 34) were determined using pre‐ and post‐test scores. Pre‐ and post‐test scores were compared using the non‐parametric Wilcoxon signed rank test, as differences do not follow a normal distribution. Our results indicate an overall significant improvement in performance between pre‐ and post‐assessment scores (p = 0.036, one‐sided). Students (n = 31) completed a post‐session survey exploring the effectiveness of instruction, pre‐work material and case‐based approach. Based on a modified Likert scale of 1–5, students found the 3D‐animation videos effective (score of 5, 64.5%; score of 4, 12.9%) in preparing for the session and future exam. Students found the case‐based approach, discussion and instruction to be highly effective (score of 5, 96.8%; score of 4, 3.2%), which strongly supports the use of this pedagogical method. We conclude that flipped, case‐based sessions integrating 3D‐animated videos are an effective method for enhancing understanding of cranial nerve structure, function and pathology.

Cranial Nerve Development, Distribution, and Function

Human evolution has produced a prodigious brain and fashioned an elaborate mechanism of convolution and gyrification to fit the neural tissue inside a rigid boney chamber. Critical systems, from olfaction and vision, to control of muscles for articulated speech, have been concentrated in the head, through a set of cranial nerves and their nuclei, located mainly in the brainstem. This presentation will trace the development, describe the distribution, and explore the functions of those cranial nerves.Early in development, dorsal and ventral columns emerge in the gray matter of the neural tube. Dorsally, the alar plate differentiates into sensory regions in both the spinal cord (dorsal horns) and the brainstem (sensory nuclei). The ventral portion of the neural tube, the basal plate, is the source of motor structures including the spinal cord ventral horn and brainstem motor nuclei. Bilaterally, a longitudinal furrow in the wall of the central canal, the sulcus limitans, divides the alar and basal plates and establishes the spatial segregation of motor and sensory neuronal systems. As the embryo elongates it differentiates into a five‐vesicle structure that is the progenitor of forebrain cerebral hemispheres and diencephalon, and brainstem midbrain, pons, and medulla.With the formation of the five‐vesicle embryo, the lumen of the central canal begins to elaborate rostrally to form the ventricular system. The lateral ventricles expand within the core of the cerebral hemispheres, and the third ventricle opens on the midline with the diencephalon forming its walls. The cerebral aqueduct is the ventricular correlate of the midbrain, connecting the third and fourth ventricles. The fourth ventricle is roughly pyramidal, tapering upward as it receives the cerebral aqueduct, being broadest at the pons‐medulla junction, and tapering again caudally to become continuous with the central canal of the spinal cord. The sulcus limitans persists in the walls of the fourth ventricle, separating alar plate derivative sensory nuclei dorsolaterally from the basal plate‐derived motor nuclei ventromedially. This effectively establishes the layout of brainstem cranial nerve nuclei. Functionally related nuclear columns are distributed throughout the rostro‐caudal length of the brainstem in consistent relative locations.Cranial nerves (CN) I (olfactory) and II (optic) are the only cranial nerves that have no brainstem nuclei, and their circuity is in the forebrain. Nuclei of CN III, the oculomotor nerve, and CN IV, the trochlear nerve occupy the midbrain. Cranial nerves V (trigeminal), VI (abducens) and the motor nucleus of CN VII (facial motor) are found in the pons, and CNn VIII (vestibulocochlear), IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal) develop in the medulla. Extensive cephalization of the brain and cranial nerves has shaped our facial morphology. The functions of the cranial nerves are well known, and predictable and diagnostic deficits appear after injuries.

Chinese consensus for mild hypothermia brain protection

Mild hypothermia, as an effective method of brain protection, has been applied in the treatment of severe craniocerebral injury, cardiac surgery and the patients after cardiopulmonary resuscitation. Although relevant guidelines, and draftsor suggestions are available in different countries, the clinical practice in this field is still obscure in China. For this reason, experts from cardiology and cardio-surgery, neurology and neurosurgery, intensive care unit, cardiopulmonary bypass, anesthesia, emergency have been organized to write Chinese consensus for mild hypothermia brain protection according to the characteristics of the mild hypothermia technology, application field, operation method and common problems etc. in conjunction with Cerebral Protection in Cardiac Intensive Care Group and Neural Intensive Nursing and Rehabilitation Group, which belong to Neural Regeneration and Repair Committee of Chinese Research Hospital Association. The consensus aims to promote the postoperative cranial nerve function in patients with rehabilitation, and it will be helpful to guide the clinical practice.

Hypofractionated Robotic Stereotactic Radiosurgery for Vagal Paragangliomas: A Novel Treatment Strategy for Cranial Nerve Preservation.

To provide the first description of hypofractionated stereotactic radiosurgery (SRS) and evaluate tumor control and safety for vagal paragangliomas (VPs), which begin at the skull base but often have significant extracranial extension. Retrospective chart review. Tertiary-referral neurotology and neurosurgery practice. Five VPs in 4 patients (all male, ages 15-56 years) underwent SRS between 2010 and 2018. Outcome measures included tumor dimensions on serial imaging, cranial nerve function, and radiation side effects. CyberKnife hypofractionated SRS was performed. The prescription dose was 24 or 27 Gy (maximum dose 33.4 Gy; range, 29.3-35.5 Gy) delivered in 3 equal fractions. The mean isodose line was 79% (range, 76%-82%). Four VPs were treated primarily, and 1 tumor underwent SRS to treat regrowth 2 years after microsurgical subtotal resection via the modified infratemporal fossa approach. The treatment volume ranged from 8.81 to 86.3 cm3 (mean, 35.7 cm3). All demonstrated stable size (n = 3) or regression (n = 2) at last follow-up, 63 to 85 months after SRS (mean, 76 months). One patient had stable premorbid vocal fold paralysis from a prior ipsilateral glomus jugulare tumor resection. All others demonstrated normal vagal function following SRS. Treatment-related side effects, including dysgeusia (n = 1), mucositis (n = 1), and neck soft-tissue edema (n = 2), were self-limited. Hypofractionated SRS appears to be both safe and effective for treating VPs, including large-volume and predominantly extracranial tumors, while preserving vagal function. SRS should be considered as a cranial nerve preservation option, especially in settings of contralateral lower cranial nerve deficits or in those with multiple paragangliomas risking both vagal nerves.