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Summary: Background: Atraumatic subarachnoid haemorrhage (SAH) is associated with high morbidity and mortality. Proposed mechanisms for red blood cell (RBC) clearance from the subarachnoid space (SAS) are erythrolysis, erythrophagocytosis or through efflux along cerebrospinal fluid (CSF) drainage routes. We aimed to elucidate the mechanisms of RBC clearance from the SAS to identify targetable efflux pathways. Methods: Autologous fluorescently-labelled RBCs along with PEGylated 40 kDa near-infrared tracer (P40D800) were infused via the cisterna magna (i.c.m.) in female reporter mice for lymphatics or for resident phagocytes. Drainage pathways for RBCs to extracranial lymphatics were evaluated by in vivo and in situ near-infrared imaging and by immunofluorescent staining on decalcified cranial tissue or dural whole-mounts. Findings: RBCs drained to the deep cervical lymph nodes 15 min post i.c.m. infusion, showing similar dynamics as P40D800 tracer. Postmortem in situ imaging and histology showed perineural accumulations of RBCs around the optic and olfactory nerves. Numerous RBCs cleared through the lymphatics of the cribriform plate, whilst histology showed no relevant fast RBC clearance through dorsal dural lymphatics or by tissue-resident macrophage-mediated phagocytosis. Interpretation: This study provides evidence for rapid RBC drainage through the cribriform plate lymphatic vessels, whilst neither fast RBC clearance through dorsal dural lymphatics nor through spinal CSF efflux or phagocytosis was observed. Similar dynamics of P40D800 and RBCs imply open pathways for clearance that do not impose a barrier for RBCs. This finding suggests further evaluation of the cribriform plate lymphatic function and potential pharmacological targeting in models of SAH. Funding: Swiss National Science Foundation (310030_189226), SwissHeart (FF191155).

Background and objective: Gross total resection of skull base meningioma is so challenging due to its relevant high morbidity. Gamma knife radiosurgery is concerned by providing a favorable therapeutic option in the management of SBM. This study aims to evaluate the neurological outcome after GKRS as an adjuvant or primary treatment for SBM according to their locations. Methods: This retrospective cross-sectional study consisted of 108 patients with SBM who underwent GKRS as an adjuvant or primary treatment. We found 40 patients with cavernous sinus meningioma (CSM), 36 patients with petroclival meningioma (PCM), and 22 patients with cerebellopontine angle meningioma (CPM). 81.1% of whom were female (n = 90) with a median age of 52.68 years. The mean tumor volume was 4.5 cm3 and the mean marginal dose was 13 Gy. Results: Tumor control was achieved in 96.4 % of patients at a median follow-up of 38.4 months. Over all 17 of 108 patients (15.6%) report improvement in their neurological symptoms. Patients with CPM demonstrated lower rates of neurological symptoms improvement compared to patients with PCM and CSM. Deterioration of neurological symptoms after GKRS developed in 11 patients (10.1%) which was more reported by patients with CSM than the others. The most improvement in cranial nerve deficit was in CN Ⅵ, Ⅴ, VIII among patients with CSM, PCM, and CPM respectively. Conclusion: GKRS is acceptable as a primary or adjuvant treatment for SBM by providing an appreciable rate of improvement in neurological symptoms.

Introduction: Paralytic strabismus, a type of strabismus caused by paralysis of one or more extraocular muscles, can lead to a variety of ocular and psychosocial sequelae. Etiology varies in different types of paralytic strabismus. Numerous studies have shown that ocular motor cranial nerve palsies have a variety of causes including vascular disease, head trauma, intracranial tumour or aneurysm and inflammatory disorders.Materials and Methods: A cross-sectional study was conducted at a tertiary eye hospital to evaluate Paralytic squint by Neuroimaging in patients presenting to the Squint department of Sarojini Devi Eye Hospital Hyderabad from June 2021 to May 2022. Paralytic strabismus cases with limitation of ocular motility were enrolled and a detailed examination was performed to know the etiology. Results: 190 patients (1.35%) were diagnosed with paralytic strabismus. Ischemia constituted to be the major cause of paralytic strabismus i.e. (42.1%) followed by trauma (20%). The 3rd cranial nerve was the most commonly involved (34.73%), followed by the 6th cranial nerve (32.63%). Multiple cranial nerves were involved in 20% of cases. The 3rd CN was involved, primarily due to ischemia in both males and females while the 6th CN was affected with trauma, neoplasm, and ischemia being prominent causes. Conclusion: The study showed that ischemia, trauma and idiopathy are some of the major etiologies of paralytic strabismus with male predominance. The cranial nerve involvement also varied with the etiology of paralytic strabismus.

Abstract Objective The management of lesions involving the cavernous sinus remains a formidable challenge. To optimize care for patients with tumors extending into this skull base region a detailed understanding of the surrounding osteology as well as neural and vascular relationships is requisite. This thesis examines the gross anatomy of the region and highlights important surgical implications drawn from these as well as previously published studies. Methods A review of the historical scientific, anatomic, clinical, and surgical literature extending to the present (1992) relating to the cavernous sinus has been performed and discussed. Additionally, the author has performed and described cadaveric dissections revealing novel details about the macroscopic (dural and neurovascular anatomic relationships) and microscopic structure of the cavernous sinus. A series of cases of cavernous sinus pathologies that were addressed in an interdisciplinary surgical approach at the author's institution is also reported. Results Included in this report is a comprehensive review of the embryology of the cavernous sinus and its associated neurovascular structures. Cadaveric dissections have also revealed novel details about dural/meningeal compartments of the cavernous sinus as well as well as associated arterial, venous, and neural relationships. Microscopic observations also reveal novel fundamental insights into the components and structure of the cavernous sinus. Clinical examples from 20 patients illustrate the critical importance for clinical application of cavernous sinus anatomic knowledge to the surgical treatment of pathologies in this region. Conclusion The cavernous sinus is a tripartite venous osteomeningeal compartment intimately neighboring vital structures including the optic tracts, pituitary gland, cranial nerves III, IV, V, V, VI, and the internal carotid artery. Surgical management of cavernous sinus lesions has and continues to evolve with increasing anatomic and clinical study as well as advancements in diagnostic and surgical methodologies. Level of Evidence NA.

Malignant otitis externa (MOE) also known as skull base osteomyelitis or necrotizing otitis externa, is a rare inflammatory and infectious condition mainly caused by Pseudomonas Aeruginosa, mainly affects elderly, diabetic and immunocompromised patients. Due to the rapidity of development, it is associated with a high rate of motility/morbidity. In this case report, we describe a rare neurological presentation in a 58-year-old male patient, diabetic, who presented with onset of right otitis externa associated with otalgia, otorrhea, and ipsilateral headache. The auricular swab was positive for Pseudomonas Aeruginosa, the necrotizing inflammation evolved rapidly with progressive clinical involvement of right cranial nerves VII, V, X (Right recurrent laryngeal nerve), III, IV, VI. The role of imaging was to confirm the initial oto-mastoid involvement and to specify the extent of the lesion. CT-scan assessed bone involvement and the MRI delineated the extent of the inflammatory pathology. During the first months of his recovery, the patient contracted SARS-COV-2 infection, which induced a clinical and radiological worsening of the initial pattern in relation to the hypoxemic states achieved in the course of interstitial pneumonia. Finally the patient was treated with Meropenem 1 g ev per day. At the end of treatment, the patient presents almost complete resolution of pathology on both clinical and radiological bases. The aim of this manuscript is to report the management and treatment of a rare case of MOE co-infected with SARS-COV-2.

Abstract Background Conductive anaesthesia of the nerves around the head is one of the methods of intraoperative pain relief (under deep anaesthesia but before proceeding with the procedure). Performing this procedure on primates is especially challenging for the veterinarian, due to their cranial anatomy and topography, which has more in common with the human skull than with the skulls of other animals. Knowledge of key bony structures, including cranial foramina, is essential for effective anaesthesia of the cranial nerves. Results In this study, the differences in the topography of the cranial foramina in eight selected species of primates were examined: Angola colobus (Colobus angolensis), Celebes crested macaque (Macaca nigra), L’Hoest’s monkey (Allochrocebus lhoesti), baboon (Papio cynocephalus), buff-bellied capuchin (Sapajus xanthosternos), black-and-white ruffed lemur (Varecia variegata), crowned lemur (Eulemur coronatus), and a ring-tailed lemur (Lemur catta) coming from the Wroclaw Zoological Garden (Poland). The cranial nerves running through the foramina have also been described and their anaesthesia techniques against bone points have been tested to relieve post-operative pain in the area of the head supplied by these nerves. Conclusion The tests carried out show differences in the topography of the cranial foramina, and therefore also differences in the methods of injection, so the results obtained in this study may be useful in veterinary medicine, especially for practising veterinarians.

Abstract Background Tuberculous meningitis, a rare but severe form of extrapulmonary tuberculosis, frequently affects cranial nerves. While nerves III, VI and VII are commonly involved, involvement of caudal cranial nerves is rarely described. Here, we report a rare case of bilateral vocal cord palsy secondary to caudal cranial nerve involvement in tuberculous meningoencephalitis, that occurred in Germany, a country with low tuberculosis incidence. Case presentation A 71-year-old woman was transferred for further treatment of hydrocephalus as a complication of presumed bacterial meningitis with unknown pathogen at that time. Because of decreased consciousness, intubation was performed and an empiric antibiotic therapy with ampicillin, ceftriaxone and acyclovir was initiated. Upon admission to our hospital, an external ventricular drainage was placed. Cerebrospinal fluid analysis revealed Mycobacterium tuberculosis as the causative pathogen, and antitubercular treatment was initiated. Extubation was possible one week after admission. Eleven days later, the patient developed inspiratory stridor that worsened within a few hours. Flexible endoscopic evaluation of swallowing (FEES) revealed new-onset bilateral vocal cord palsy as the cause of respiratory distress, which required re-intubation and tracheostomy. The bilateral vocal cord palsy persisted despite continued antitubercular therapy on the follow-up examination. Conclusion Considering the aetiology of infectious meningitis, cranial nerve palsies may be suggestive for tuberculous meningitis as underlying disease given their rarity in other bacterial forms of meningitis. Nevertheless, intracranial involvement of inferior cranial nerves is rare even in this specific entity, as only extracranial lesions of inferior cranial nerves have been reported in tuberculosis. With this report of a rare case of bilateral vocal cord palsy due to intracranial involvement of the vagal nerves, we emphasize the importance of timely initiation of treatment for tuberculous meningitis. This may help to prevent serious complications and associated poor outcome since the response to anti-tuberculosis therapy may be limited.

Abstract Introduction Nose‐to‐brain (N2B) insulin delivery has potential for Alzheimer's disease (AD) therapy. However, clinical implementation has been challenging without methods to follow N2B delivery non‐invasively. Positron emission tomography (PET) was applied to measure F‐18‐labeled insulin ([18F]FB‐insulin) from intranasal dosing to brain uptake in non‐human primates following N2B delivery. Methods [18F]FB‐insulin was prepared by reacting A1,B29‐di(tert‐butyloxycarbonyl)insulin with [18F]‐N‐succinimidyl‐4‐fluorobenzoate. Three methods of N2B delivery for [18F]FB‐insulin were compared – delivery as aerosol via tubing (rhesus macaque, n = 2), as aerosol via preplaced catheter (rhesus macaque, n = 3), and as solution via preplaced catheter (cynomolgus macaque, n = 3). Following dosing, dynamic PET imaging (120 min) quantified delivery efficiency to the nasal cavity and whole brain. Area under the time‐activity curve was calculated for 46 regions of the cynomolgus macaque brain to determine regional [18F]FB‐insulin levels. Results Liquid instillation of [18F]FB‐insulin by catheter outperformed aerosol methods for delivery to the subject (39.89% injected dose vs 10.03% for aerosol via tubing, 0.17% for aerosol by catheter) and subsequently to brain (0.34% injected dose vs 0.00020% for aerosol via tubing, 0.05% for aerosol by catheter). [18F]FB‐insulin was rapidly transferred across the cribriform plate to limbic and frontotemporal areas responsible for emotional and memory processing. [18F]FB‐insulin half‐life was longer in olfactory nerve projection sites with high insulin receptor density compared to the whole brain. Discussion The catheter‐based liquid delivery approach combined with PET imaging successfully tracked the fate of N2B [18F]FB‐insulin and is thought to be broadly applicable for assessments of other therapeutic agents. This method can be rapidly applied in humans to advance clinical evaluation of N2B insulin as an AD therapeutic. Highlights for [18F]FB‐insulin passage across the cribriform plate was detected by PET. Intranasal [18F]FB‐insulin reached the brain within 13 min. [18F]FB‐insulin activity was highest in emotional and memory processing regions. Aerosol delivery was less efficient than liquid instillation by preplaced catheter. Insulin delivery to the cribriform plate was critical for arrival in the brain.

Introduction Cranial nerve involvement in polyarteritis nodosa(PAN) is underrecognized and rarely reported. The aim of this article is to review the available literature and present an example of oculomotor nerve palsy in the course of PAN. Material and Methods Evaluation of texts describing the analyzed problem using the terms “polyarteritis nodosa”, “nerve”, “oculomotor”, “cranial nerve” and “cranial neuropathy” for searching the PubMed database was done. Only full-text articles in English language with titles and abstracts were included in the analysis. As a guideline for the analysis of articles, the methodology described in the Principles of Individual Patient Data systematic reviews (PRISMA-IPD) was used. Results After screening articles only 16 reported cases of PAN with cranial neuropathy were included in the analysis. In 10 the cranial neuropathy was reported as the initial manifestation of PAN with optic nerve involvement as the most frequent (62.5%); among these cases the oculomotor nerve was in-volved in 3 cases. Treatment with glucocorticosteroids and cyclophosphamide was the most com-mon. Conclusions Although cranial neuropathy, especially oculomotor nerve palsy is a rare first neurological manifesta-tion of PAN, this clinical problem should be considered in the differential diagnosis. Especially patients with peripheral neuropathy, general symptoms, skin lesions and hepatitis B virus infection should be evaluated for cranial nerve involvement in the course of vasculitis. In the case of unclear involvement of the cranial nerves, PAN should also be considered in the differential diagnosis as the cause of symptoms and the first manifestation of the disease.

Abstract Introduction NEUROG1 gene is yet to be associated with a set of human phenotypes in the OMIM database. Three cases have previously been diagnosed with cranial dysinnervation due to biallelic variants in the NEUROG1 gene. This is the fourth and a novel report of a sibling pair harboring a homozygous variant in the NEUROG1 gene with autism as an additional phenotype. A brief review of the literature in conjunction with a genotype–phenotype correlation has been described. A potential hypothesis for the presence of the autistic phenotype in the present case has also been elucidated. Case presentation A female aged 6 years and 9 months born to endogamous and phenotypically healthy parents was diagnosed with global developmental delay, autism spectrum disorder, hearing loss, corneal opacity and no eye blinking. Her MRI of the brain revealed mild peritrigonal white matter hyperintensity, and MRI and CT scan of the temporal bones showed abnormal cranial nerves. The proband’s younger sister, aged 4-years, was similarly affected. Whole exome sequencing was performed in the proband, which revealed a novel homozygous, likely pathogenic, truncating frameshift variant, c.228_231dup (p.Thr78ProfsTer122) in exon 1 of the NEUROG1 gene (ENST00000314744.4). Segregation analysis by Sanger sequencing showed the proband and her younger sister to be homozygotes and their parents to be heterozygous carriers. Conclusion This is the fourth report across the globe with a variant identified in the NEUROG1 gene to be associated with cranial dysinnervation phenotype. An additional phenotype of autism in two female siblings was a novel observation. We provide a hypothetical framework which could explain the pleiotropic effect of a dysfunctional NEUROG1 protein leading to autism and posit it as a candidate for diagnosis of autism spectrum disorder with congenital cranial dysinnervation disorder.

Neurofibromatosis (NF) type 2 is a rare neurological, autosomal dominant and genetic disorder. It is caused by a mutation in the tumor suppressor gene, called NF2 gene. The disorder results in several benign tumors of the nervous system. These typically include vestibular schwannomas, meningiomas, and ependymomas. Multiple cranial nerve abnormalities affect the brain, spinal cord, nerves, and skin and cause significant morbidity in patients. We describe a 20-year-old patient, with a family history of brain tumors, with symptoms of left sided third nerve palsy. Magnetic Resonance Imaging (MRI) of the brain and orbits revealed a small sized cavernous sinus meningioma and bilateral vestibular schwannomas. As per the differential diagnosis and optimal resolution brain imaging, NF2 was diagnosed. The patient was referred for specific treatment to the neuro-oncology unit. The case is distinct as the patient presented with a parasellar meningioma leading to third nerve palsy besides bilateral vestibular schwannomas. Manchester criteria and high contrast MR imaging proved more beneficial in our patient for the diagnosis of a wider clinical spectrum of NF2.

The purpose of this study was to review the diagnostic accuracy of MRI in detecting perineural spreading (PNS) of head and neck tumors using histopathological or surgical evidence from the afflicted nerve as the reference standard. Previous studies in the English language published in the last 30 years were searched from PubMed and Embase databases. We included studies that used magnetic resonance imaging (MRI) (with and without contrast enhancement) to detect PNS, as well as the histological or surgical confirmation of PNS, and that reported the exact numbers of patients required for assessing diagnostic accuracy. The outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Heterogeneity was assessed with the Higgins inconsistency test (I2). P-values smaller than 0.05 were considered statistically significant. A total of 11 retrospective studies were found, reporting 319 nerve samples from 245 patients. Meta-analytic estimates and their 95% confidence intervals were as follows: sensitivity 0.85 (0.70–0.95), specificity 0.85 (0.80–0.89), PPV 0.86 (0.70–0.94), and NPV 0.85 (0.71–0.93). We found statistically significant heterogeneity for sensitivity (I2 = 72%, p = 0.003) and PPV (I2 = 70%, p = 0.038), but not for NPV (I2 = 65%, p = 0.119) or specificity (I2 = 12%, p = 0.842). The most frequent MRI features of PNS were nerve enlargement and enhancement. Squamous cell carcinoma and adenoid cystic carcinoma were the most common tumor types, and the facial and trigeminal nerves were the most commonly affected nerves in PNS. Only a few studies provided examples of false MRI diagnoses. MRI demonstrated high diagnostic accuracy in depicting PNS of cranial nerves, yet this statement was based on scarce and heterogeneous evidence.

Miller-Fisher syndrome (MFS), defined as a rare variant of Guillain-Barré syndrome (GBS), is characterized by the classic triad of ataxia, areflexia, and ophthal-moplegia. It is a demyelinating polyneuropathy resulting from a deregulated autoimmune response secondary to infection by viruses and bacteria. SMF and GBS have been described during the COVID-19 pandemic. There are some reports in the literature of GBS after vaccination for COVID-19. In contrast, reports of post-vaccination FMS for SARS-CoV-2 are scarce in the literature. A 75-year-old patient is presented who consults for asthenia, adynamia, and difficulty swallowing that progresses to respiratory distress. She refers to the application of the Sputnik V vaccine as an important antecedent. During the hospital stay, the diagnosis was made by electromyography and nerve conduction study of GBS variant SMF. The objective is to expose a post-vaccination SMF to SARS-CoV-2 with the biological Sputnik V and highlight the importance of this background for surveillance in clinical practice and future research.

Key Clinical Message This case report highlights the importance of considering scrub typhus as a differential diagnosis for acute encephalitis with cranial nerve palsy in the region of the tsutsugamushi triangle. Abstract Scrub typhus is a zoonotic rickettsiosis caused by the bacterium Orientia tsutsugamushi. This disease is endemic to a region called the tsutsugamushi triangle that extends from Southeast Asia to the Pacific Ocean. We report a 17‐year‐old girl from western Nepal who presented with fever, headache, vomiting, and altered sensorium, as well as bilateral lateral rectus palsy, dysphagia, regurgitation of food, dysarthria, and left‐sided upper motor neuron type facial palsy. Following laboratory and imaging tests, the patient was diagnosed with scrub typhus and was treated successfully with high‐dose dexamethasone and doxycycline. This case highlights the importance of considering scrub typhus in the differential diagnosis of encephalitis with cranial nerve palsy, especially in the region of the tsutsugamushi triangle. It also emphasizes the need for timely diagnosis and treatment of scrub typhus to prevent the development of various complications and ensure earlier recovery of patients.

ABSTRACT: Intracranial tumors occurring in specific brain regions, such as the cerebellopontine angle, may be associated with cranial nerve dysfunction and dysphagia in humans and animals. Although dysphagia is a known risk factor for pneumonia, only postoperative pneumonia has been investigated in veterinary medicine. This study aimed to describe the clinical and pathological features of dogs with untreated intracranial meningiomas and concomitant pneumonia. Data from post-mortem examination registries from 2011 to 2021 were used (n=23). The frequency of pneumonia and other characteristics were compared between dogs with meningiomas in the ventral rhombencephalon region (VR group; n=13) and those with meningiomas in other intracranial sites (OIS group; n=10). The frequency of pneumonia was higher in the VR group than in the OIS group (n=5 vs. n=0; P=0.039). Plaque-like lesions were also more common in the VR group than in the OIS group (P=0.012). Dogs with concomitant pneumonia had cerebellopontine angle (n=3) and basilar meningiomas (n=2), mainly plaque-like lesions extending to or from other brain areas. In dogs with concomitant pneumonia, meningiomas had invasive (n=5) and compressive (n=3) growth behaviors and nerve roots involved in the swallowing process were frequently affected. Microscopically, these meningiomas were classified as atypical (n=4) and meningiomas (n=1). The reported clinical signs included anorexia (n=3), adipsia (n=1), and dysphagia (n=1). Our findings suggest untreated dogs with ventral rhombencephalon meningiomas may develop cranial nerve damage and aspiration pneumonia.

Abducens nerve palsy is a common ocular motor paralysis with a broad set of etiopathogenetic causes. Magnetic resonance imaging is a key diagnostic technique to investigate organic causes of sixth nerve palsy, as it allows a detailed representation of the course of the nerve, particularly in its intracisternal tract. Anatomical variants of the sixth cranial nerve comprise duplications and fenestrations in various traits. Anatomical variants of cerebellar arteries have also been described. We report the case of a patient with abducens nerve palsy presumably related to a neurovascular conflict due to a peculiar anatomical variant, which consists in a cerebellar artery passing through the intracisternal duplication of the abducens nerve.

Doctors of various specialties face orofacial pain in their practice: dentists, maxillofacial surgeons, neurologists, otorhinolaryngologists, therapists, traumatologists, ophthalmologists, psychotherapists, physiotherapists, aesthetic medicine doctors, neurosurgeons, anesthesiologists, plastic surgeons and other specialists. The novel coronavirus infection (COVID-19) pandemic, spread by the SARS-CoV-2 virus, has become a challenge for all medical specialties and health care systems around the world. We searched the literature for the period from the beginning of the pandemic until June 15, 2022, on the study of the association of orofacial pain with a new coronavirus infection COVID-19 in the electronic search engines PubMed and Scopus. An analysis of the sources found indicates an increase in the frequency of various types of orofacial pain during the COVID-19 pandemic, which is due both to the SARS-CoV-2 infection itself and to a complex of biopsychosocial factors directly related to the pandemic. A number of used drugs, primarily non-steroidal anti-inflammatory drugs, can cause a number of side effects that complicate both dental treatment and negatively affect concomitant comorbid pathology. In this regard, the issues of drug safety and pharmacological "correction" of side effects – protective or protector therapy – become relevant. The use of the universal gastro- and enteroprotector rebamipide is especially important during the pandemic of a new coronavirus infection (COVID-19).

Medical history, disease onset, clinical symptoms, and results of neuroimaging of 14 glossopharyngeal schwannoma patients, who were exa­mined and treated in the Subtentorial Neurooncology Department of the State Institution, Romodanov Institute of Neurosurgery of the NAMS of Ukraine (8 patients) and the Neurosurgery Department No. 2 of the Municipal Enterprise, Mechnikov Dnipropetrovsk Regional Clinical Hospital of Dnipropetrovsk Regional Council (6 patients) in 2018 to 2021 have been analyzed in details. The study inclusion criteria were as follows: patient’s age over 18, pre­sence of unilateral primary glossopharyngeal nerve schwannoma. Our study showed that most of clinical signs and symptoms of the glossopharyngeal nerve schwannoma are associated with otolaryngological disorders (such as hearing loss, tinnitus, hoarseness, or dizziness) or cerebellar disorders (such as ataxia, nystagmus, or dizziness). Neuroimaging cerebellopontine angle tumors diagnosis must include brain computed tomography (with mandatory assessment of the state of jugular foramen and internal auditory canal) and IV contrast brain magnetic resonance tomography and inclusion of high-resolution sequences, gradient echo (3D CISS, DRIVE, TRUFFI, B-FFE) with the aim of better visualization and differentiation of various cerebellopontine angle cranial nerves. The study demonstrates the com­plexity of a reliable preoperative diagnosis when using standard diagnostic tools. Preoperative jugular foramen and cerebellopontine angle tumors diagnosis should be based on a systematic approach and include a comparison of results of comprehensive clinical and instrumental examination and neuroimaging studies.

Abstract Background One of the largest outbreaks of rhinosinocerebral mucormycosis (RSCM) occurred in India close to the second wave of the SARS-CoV-2 infection. RSCM is a rare infection caused by several fungal species occurring in immunocompromised subjects. Mucor shows a high propensity to invade the central nervous system. There have been limited studies, mostly isolated case reports, on the neurological manifestations of RSCM. The outbreak of mucormycosis infection was thus the most opportune to study the neurological manifestations and cranial nerve involvement in mucormycosis in greater depths. Aim of the study The purpose of the study was to investigate and review the involvement of cranial nerves in a series of cases of rhinosinocerebral mucormycosis associated with the novel coronavirus disease caused by SARS-CoV-2. Results It was a retrospective cross-sectional study of seven patients who were undergoing treatment of RSCM with a recent history of coronavirus disease caused by SARS-CoV-2 infection within the last 3 months. Patients with cranial nerve involvement were identified by magnetic resonance imaging (MRI) at a single institution. Demographic details of the patients, clinical presentation, imaging, microbiological and pathological findings were recorded. All subjects had two or more cranial nerves affected by fungal infection. The most commonly involved cranial nerve was found to be the optic nerve followed by the trigeminal nerve and its branches. We document three cases with extensive involvement of the inferior alveolar branch of the mandibular division of the trigeminal nerve (V3), a previously unreported finding. In one case, in addition to the second and fifth cranial nerves, the third, fourth, sixth, seventh, eighth, and twelfth cranial nerves were involved without any sensory or motor long tract involvement, suggestive of Garcin syndrome secondary to intracranial abscesses and skull base osteomyelitis due to invasive fungal infection. This case is of rare occurrence in the literature, and our study provides one such example. Conclusion Cranial nerve involvement in patients of mucormycosis tends to have a poor prognosis, both cosmetic and functional. Radical surgeries and aggressive medical management is needed in such cases to improve the outcome.

Forming a vertebrate head involves the meticulous integration of multiple tissue types during development. Prenatal alcohol exposure is known to cause a variety of birth defects, especially to tissues in the vertebrate head. However, a systematic analysis of coordinated defects across tissues in the head is lacking. Here, we delineate the effects of ethanol on individual tissue types and their integration during craniofacial development. We found that exposure to 1% ethanol induced ectopic cranial muscle and nerve defects with only slight effects on skeletal pattern. Ectopic muscles were, however, unaccompanied by ectopic tendons and could be partially rescued by anesthetizing the larvae before muscle fibers appeared. This finding suggests that the ectopic muscles result from fiber detachment and are not due to an underlying muscle patterning defect. Interestingly, immobilization did not rescue the nerve defects, thus ethanol has an independent effect on each tissue even though they are linked in developmental time and space. Time-course experiments demonstrated an increase in nerve defects with ethanol exposure between 48hpf-4dpf. Time-lapse imaging confirmed the absence of nerve pathfinding or misrouting defects until 48hpf. These results indicate that ethanol-induced nerve defects occur at the time of muscle innervation and after musculoskeletal patterning. Further, we investigated the effect of ethanol on the neuromuscular junctions of the craniofacial muscles and found a reduced number of postsynaptic receptors with no significant effect on the presynaptic terminals. Our study shows that craniofacial soft tissues are particularly susceptible to ethanol-induced damage and that these defects appear independent from one another. Thus, the effects of ethanol on the vertebrate head appear highly pleiotropic.

Garcin syndrome is characterized by progressive unilateral multiple cranial nerve palsy without the presence of intracranial hypertension. In this case, we present a patient who experienced lower cranial nerve (CN 9–12) involvement attributed to post-mucormycosis osteomyelitis of the skull base. The osteomyelitis resulting from mucormycosis led to the development of Garcin syndrome, which manifested as progressive paralysis of the cranial nerves. It is important to recognize this rare complication and consider it in the differential diagnosis when evaluating patients with lower cranial nerve palsy following mucormycosis-related skull base osteomyelitis.

Vision is a complex sense that is widely represented in the cortex and involves multiple pathways that can be affected by conditions amenable to surgical treatment. From a neurosurgical point of view, the treatment of major lesions affecting the optic nerve, such as tumours, intracranial hypertension, trauma and aneurysms, can be approached depending on the segment to be worked on and the surrounding structures to be manipulated. Therefore, surgical manipulation of the visual pathway requires a detailed knowledge of functional neuroanatomy. The aim of this review is to present the functional and microsurgical anatomy of the second cranial nerve, through illustrations and cadaveric dissections, to support the choice of the best surgical approach and avoid iatrogenic injuries. For this purpose, a literature search was performed using the PubMed database. Additionally, cadaveric dissections were performed on adult cadaver heads fixed with formaldehyde and injected with coloured silicone.

Careful phenotype analysis of genetically altered mouse embryos/fetuses is vital for deciphering the function of pre- and perinatally lethal genes. Usually this involves comparing the anatomy of mutants with that of wild types of identical developmental stages. Detailed three dimensional information on regular cranial nerve (CN) anatomy of prenatal mice is very scarce. We therefore set out to provide such information to be used as reference data and selected mutants to demonstrate its potential for diagnosing CN abnormalities. Digital volume data of 152 wild type mice, harvested on embryonic day (E)14.5 and of 18 mutants of the Col4a2, Arid1b, Rpgrip1l and Cc2d2a null lines were examined. The volume data had been created with High Resolution Episcopic Microscopy (HREM) as part of the deciphering the mechanisms of developmental disorders (DMDD) program. Employing volume and surface models, oblique slicing and digital measuring tools, we provide highly detailed anatomic descriptions of the CNs and measurements of the diameter of selected segments. Specifics of the developmental stages of E14.5 mice and anatomic norm variations were acknowledged. Using the provided data as reference enabled us to objectively diagnose CN abnormalities, such as abnormal formation of CN3 (Col4a2), neuroma of the motor portion of CN5 (Arid1b), thinning of CN7 (Rpgrip1l) and abnormal topology of CN12 (Cc2d2a). Although, in a first glimpse perceived as unspectacular, defects of the motor CN5 or CN7, like enlargement or thinning can cause death of newborns, by hindering feeding. Furthermore, abnormal topology of CN12 was recently identified as a highly reliable marker for low penetrating, but potentially lethal defects of the central nervous system.

Twelve pairs of cranial nerves control the sensory and motor functions of the head and neck region, with exception of the tenth nerve, the vagus nerve which also is responsible for the parasympathetic and viscerosensory innervation of the thoracoabdominal organs. MRI is the cornerstone in the study of cranial nerves. Next to the traditional sequences that depict general anatomical findings and pathological changes, two additional sequences should be included in every imaging protocol for cranial nerves. High-resolution steady-state free precession is important for the visualization of the cisternal courses of the cranial nerves. These sequences have a high spatial resolution and additionally show dark cranial nerves against a background of bright CSF. Three-dimensional T1-weighted GE sequences, preferentially with fat suppression, provide a good evaluation of nerve enhancement. The twelve cranial nerves are individually discussed from the intra-axial segments to the distal extracranial branches. There is a specific emphasis on the connections between different cranial nerves. Finally, new imaging techniques are highlighted.

Prof. Madjid Samii is an internationally recognized neurosurgeon who has conquered the highest levels of 21st-century neurosurgery. Born in Iran, he decided to take medical courses at the University of Mainz, Hanover, Germany. He earned his medical degree in 1963, marking the highest achievable score, and started his residency, guided by Emeritus Professor Dr Kurt Schurmann. Numerous various surgeries and studies that reshaped the field of neurosurgery describe his career. Starting with a publication regarding a new technique, pneumencephalotomography, he has steadily been ascending, studying and writing about cranial nerves, developing the surgery of the skull base and proving that the transnasal approach is preferred in clivus chondromas. Prof. Madjid Samii founded, 1990, the Foundation of National and Continental Skull Base Societies, and since 2001, he has been the Honorary President of the World Federation of Neurosurgery Societies(WFNS). Not only was he successful in his scientific path, but he also gave an example for the future generation of what astonishing results can be obtained with hard work, commitment, and a leader's spirit. He wanted to take worldwide neurosurgery to a whole new level, so he came up with an idea, the concept of an international neuro-excellence centre, which quickly became the reality of the International Neuroscience Institute of Hanover.

Prof. Madjid Samii is an internationally recognized neurosurgeon who has conquered the highest levels of 21st-century neurosurgery. Born in Iran, he decided to take medical courses at the University of Mainz, Hanover, Germany. He earned his medical degree in 1963, marking the highest achievable score, and started his residency, guided by Emeritus Professor Dr Kurt Schurmann. Numerous various surgeries and studies that reshaped the field of neurosurgery describe his career. Starting with a publication regarding a new technique, pneumencephalotomography, he has steadily been ascending, studying and writing about cranial nerves, developing the surgery of the skull base and proving that the transnasal approach is preferred in clivus chondromas. Prof. Madjid Samii founded, 1990, the Foundation of National and Continental Skull Base Societies, and since 2001, he has been the Honorary President of the World Federation of Neurosurgery Societies(WFNS). Not only was he successful in his scientific path, but he also gave an example for the future generation of what astonishing results can be obtained with hard work, commitment, and a leader's spirit. He wanted to take worldwide neurosurgery to a whole new level, so he came up with an idea, the concept of an international neuro-excellence centre, which quickly became the reality of the International Neuroscience Institute of Hanover.

Objective To investigate the effect of neurophysiological monitoring in extended endoscopic transsphenoidal surgery for cavernous sinus and clivus tumors. Methods We monitored the oculomotor nerve, trochlear nerve, trigeminal nerve and abducent nerve in 18 patients with cavernous sinus and clivus tumors by recording the free⁃electromyography (f⁃EMG) and triggered⁃electromyography (t⁃EMG) from August 2019 to December 2020. Two needle electrodes were inserted percutaneous into the levator palpebrae superioris muscle, superior oblique muscle, extraocular rectus muscle and masticatory muscle. To evaluate spontaneous muscle activity and complex muscle action potentials after cranial nerve stimulation. We evaluated the safety of cranial nerves and provided objective information for neurosurgeon. Results All the 18 patients with cavernous sinus and clivus tumors were treated by extended endoscopic transsphenoidal surgery, including 10 pituitary adenomas, 5 chordomas, 2 craniopharyngiomas and one cystic schwannoma. Total resection rate achieved 9/18, subtotal resection rate was 4/18, and partial resection rate was 5/18. There was no postoperative internal carotid artery (ICA) injury and cerebrospinal fluid leakage. A total of 20 oculomotor nerves, 3 trochlear nerves, 27 trigeminal nerves and 26 abducent nerves were recorded. There were one patient with left abducent nerve palsy and one patient with right abducent nerve paresis before surgery. The median follow⁃up time was 8.63 months, postoperative brain nerve injury occurred in 2 patients, the brain nerve injury rate was 2/18, all of which recovered 3 months after surgery. No patients with postoperative impaired trigeminal nerve function. Conclusions Monitoring of oculomotor nerve, trochlear nerve, trigeminal nerve and abducent nerve in extended endoscopic transsphenoidal surgery for cavernous sinus and clivus tumors is a safe and effective method. By monitoring and evaluating intraoperative f ⁃ EMG and t ⁃ EMG, neurosurgeons can adjust surgical procedures and strategies during tumor resection and reduce cranial nerve injuries.

Sensorineural hearing loss (SNHL) has been reported rarely in patients with meningeal carcinomatosis (MC). We summarized the clinical data of eight MC patients with SNHL and 35 patients reported from publications. In the eight patients with SNHL, the medium onset age was 48 (range from 37 to 66) years and six (75%) were male. Seven (87.5%) suffered from headaches as the initial symptom, and they experienced SNHL during the first two months after the occurrence of headaches (0.5 to 2 months, average 1.5 months). The audiogram configuration was flat in three patients (37.5%) and showed total deafness in five patients (62.5%). The damage of cranial nerves VI (abducens) was observed in six patients (75%), and four patients (50%) had cranial nerves VII (facial) injury during the disease course. The percentage of damage of cranial nerves was higher than the patients without SNHL (VIth, 75.0% vs. 13.3%, p = 0.002 and VIIth 50.0% vs. 6.7%, p = 0.012). Four (50%) patients suffered from lung adenocarcinoma as primary tumor, two (25%) experienced stomach adenocarcinoma, one had colon cancer, and one patient was unknown. The symptom of SNHL improved after individualized therapy in four patients (focal radiotherapy and chemotherapy for three patients and whole brain radiotherapy for one patient), but all passed away from 2 to 11 months after diagnosis. Total deafness and flat hearing loss in audiogram were the common types of SNHL resulting from MC. MC patients with SNHL were more likely to suffer from the damage of other cranial nerves, especially to cranial nerves VI and VII. Treatment might improve SNHL, but not improve the case fatality rate.

Abstract Background Several investigations were carried out during the pandemic, demonstrating a number of neurological symptoms linked to coronavirus disease 2019 (COVID‐19) infection. Objectives The goal of this review is to discuss COVID‐19 disease's neurological signs and squeals. Methodology From December 2019 to May 2020, data were retrieved from PubMed, Scopus, and ScienceDirect, as well as a manual search using Google Scholar. COVID‐19, neurological symptoms, cranial nerves, motor system were among the key phrases utilized in the search. Results The intensity of respiratory involvement increases the likelihood of neurological symptoms and consequences. According to some research, it might range from 34% to 80%. The central and peripheral neural systems are both affected, resulting in cranial nerve palsies and limb paralysis. Conclusion COVID‐19 neurologic complications are key drivers of patient severity and mortality. Headache, convulsions, mental and psychic disorders, delirium, and insomnia are just some of the symptoms that the virus can cause. The olfactory nerve is the most commonly damaged cranial nerve, resulting in anosmia. Stroke (mostly infarction), encephalitis, meningitis, Guillain–Barre syndrome, relapse of multiple sclerosis, and transverse myelitis are all symptoms and squeals.

Objective To summarize the clinical features and outcomes of patients with rhinocerebral mucormycosis involving cranial nerve. Methods and Results Eight pathologic confirmed cases of rhinocerebral mucormycosis with cranial nerves involvement since February 2012 to January 2020 were collected and evaluated. All patients were diagnosed at Beijing Tongren Hospital, Capital Medical University. The main clinical manifestations were headache, eye and face swelling. In addition to the paranasal sinuses, the ocular motor nerve, extraocular muscle, meninges, brain parenchyma, optic nerve, cerebrovascular and vestibulocochlear nerve were also involved. There were 5 patients with the primary disease of type 2 diabetes mellitus, one patient with acute leukemia receiving chemotherapy, one patient with severe aplastic anemia receiving immunosuppressive therapy, and one patient with craniocerebral trauma. Six patients were confirmed by pathological biopsy of paranasal sinus mucosa, the other 2 patients underwent brain parenchymal biopsy and temporal muscle biopsy respectively. In addition to one patient with meningeal involvement who gave up treatment and finally died, the other 7 patients received amphotericin B (one case was combined with posaconazole) or amphotericin B liposome antifungal therapy. Among them 4 patients underwent simultaneous transnasal endoscopic radical lesion removal treatment and 3 patients with brain parenchymal involvement died despite of active treatment. Conclusions The mortality of rhinocerebral mucormycosis with brain parenchyma involvement is extremely high. For patients with sinusitis with immunocompromised state, if there is acute progression of cranial nerve involvement, swelling around the eyes and headache, attention should be paid to the identification of the disease, and antifungal drugs and combined surgery treatment should be given early. Pathological biopsy of the affected mucosal tissue is the first choice for quick diagnosis.

Abstract Background Neurolymphomatosis involving the cranial nerves (CNs) is rare. We sought a better understanding of the primary disease sites and patterns of spread in neurolymphomatosis of the orbit and retro-orbital cranial nerves. Methods Patients with lymphoma and MRI evidence of neurolymphomatosis of CN II, III, IV, V1, or V2 were retrospectively reviewed. Demographics and primary disease site and sites of neurolymphomatosis on MRI were recorded. Wilcoxon rank sum test was used to compare number of sites of neurolymphomatosis with lymphoma type and survival. Results The study included 18 patients. The most frequent types of lymphoma were diffuse large B-cell (DLBCL) (n = 9) and marginal zone (n = 3). In 9 patients, lymphoma presented as a mass (n = 7) or infiltrative disease (n = 2) directly involving the orbit; in 6, a maxillofacial mass spread directly to CNs; and in 3, lymphoma at remote sites spread to orbital CNs. Overall, 81 sites of neurolymphomatosis were noted. The most common sites were the maxillary nerve (V2) including at the infraorbital fissure or foramen rotundum (17 patients; 19 nerves), pterygopalatine fossa (16 patients; 19 nerves), and cavernous sinus (9 patients; 12 nerves). Number of sites of neurolymphomatosis was significantly lower for DLBCL than for other lymphoma types (p = 0.007). Number of sites of neurolymphomatosis did not affect survival (p = 0.26). The mean interval between the pathologic diagnosis and MRI documentation of the full extent of neurolymphomatosis was 39 days after pathologic diagnosis. Conclusions Based on our study results, neurolymphomatosis in the orbit appears to be frequently associated with an orbital and/or maxillofacial mass and commonly involves CN V2, the pterygopalatine fossa, and the cavernous sinus. DLBCL may be associated with fewer sites of neurolymphomatosis than other lymphomas. In patients with lymphoma, a systematic search for neurolymphomatosis is imperative for early detection.

Introducción: Among the broad range of symptoms of the Guillain-Barré Syndrome (GBS), patients can present craniofacial manifestations. Consequently, the participation of the dental surgeon in the evaluation of the stomatognathic system using a multidisciplinary approach model is very important. Objective: To identify the craniofacial and neurological manifestations of the Guillain-Barré Syndrome in patients from three hospitals in the district of Lambayeque, Peru, in 2019. Material and Methods: A descriptive, prospective, and cross-sectional study was carried out in 59 patients diagnosed with GBS by means of a clinical evaluation carried out by previously calibrated neurologists (k=0.911). Additionally, an oral evaluation of the oral hygiene index, the periodontal status, and the oral pH was carried out. Data were processed using frequency distribution tables. Results: 44.07% of the patients presented at least one functional alteration, such as unilateral limitation for facial expressions (25.42%), dysphagia (18.64%), alteration in phonation (11.86%), and loss of the sense of taste (6.78%), showing involvement of the corresponding cranial nerves. In addition, unfavorable conditions oforal hygiene and acid pH were observed in some cases, which proved adverse for the periodontal structures of the patients. Conclusion: The study found craniofacial manifestations of GBS, such as cases of unilateral facial palsy, dysphagia, difficulty in phonation, and loss of the sense of taste, due to the alteration of the cranial nerves that command these functions. In addition, poor oral hygiene, and the presence of acidic pH in some patients created an adverse environment for the integrity of the periodontal structures.

Neck pain (NP) is the second most common musculoskeletal disorder. Spinal cysts (SCs) are cystic dilatations of the synovial sheaths in joints and tendons. SCs are extremely rare in the cervical spine. Typically, patients are unaware of having an SC due to its asymptomatic nature; however, when cervical SC extends, its volume could compress the surrounding structures, such as the hypoglossal nerve. Isolated hypoglossal nerve palsy (HNP) is very rare and typically presents with unilateral atrophy of the musculature of the tongue and contralateral tongue deviation. Often, patients with HNP also report occipital/neck pain. A 75-year-old man with occipital/neck pain as a primary complaint. Although difficult to observe because of the filtering facepiece two mask, difficulties in articulation and sialorrhea during the interview were noticed. These latter were cues to consider CN examination that revealed CN XII palsy. This prompted a referral for further examination that revealed an SC compressing the right hypoglossal canal. The patient was not considered a surgical candidate and was managed conservatively. This case report outlines the relevant findings relating to the triage of a rare isolated hypoglossal nerve palsy from the physiotherapist’s perspective within a complex setting because of the COVID-19 pandemic. Although referred with a diagnosis of cervical radiculopathy, our case highlights that skilled physiotherapists may play a fundamental role in both the recognition and, when applicable, subsequent novel management of a non-musculoskeletal presentation.

Carlos Suárez,1,2 Fernando López,1– 3 William M Mendenhall,4 Simon Andreasen5– 7†, Lauge Hjorth Mikkelsen,7 Johannes A Langendijk,8 Stefano Bondi,9 Juan P Rodrigo,1– 3 Leif Bäck,10 Antti A Mäkitie,10– 12 Verónica Fernández-Alvarez,13 Andrés Coca-Pelaz,1– 3 Robert Smee,14 Alessandra Rinaldo,15 Alfio Ferlito16 1Instituto de Investigación Sanitaria del Principado de Asturias and CIBERONC, ISCIII, Oviedo, Spain; 2Instituto Universitario de Oncología del Principado de Asturias, Universidad of Oviedo, Oviedo, Spain; 3Department of Otorhinolaryngology, Hospital Universitario Central de Asturias, Oviedo, Spain; 4Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, USA; 5Department of Otorhinolaryngology Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark; 6Department of Otorhinolaryngology and Maxillofacial Surgery, Zealand University Hospital, Køge, Denmark; 7Department of Pathology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; 8Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; 9Department of Otorhinolaryngology-Head and Neck Surgery, San Raffaele Hospital, Vita-Salute University, Milan, Italy; 10Department of Otorhinolaryngology - Head and Neck Surgery, University of Helsinki, Helsinki University Hospital, Helsinki, Finland; 11Research Program in Systems Oncology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; 12Division of Ear, Nose and Throat Diseases, Department of Clinical Sciences, Intervention and Technology, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden; 13Vascular Surgery Department, Hospital Universitario Central de Asturias, Oviedo, Spain; 14Department of Radiation Oncology, The Prince of Wales Cancer Centre, Sydney, NSW, Australia; 15University of Udine School of Medicine, Udine, Italy; 16International Head and Neck Scientific Group, Padua, Italy†Simon Andreasen passed away on February 28, 2020Correspondence: Carlos SuárezInstituto de Investigación Sanitaria del Principado de Asturias and CIBERONC, ISCIII, Avenida de Roma s/n, Oviedo 33011, SpainEmail csuareznieto@gmail.comFernando LópezDepartment of Otorhinolaryngology, Hospital Universitario Central de Asturias, Avenida de Roma s/n, Oviedo 33011, SpainEmail flopez_1981@yahoo.esAbstract: The aim of this review is to analyze the latest trends in the management of non-vestibular skull base and intracranial schwannomas in order to optimize tumor control and quality of life. Non-vestibular cranial nerve schwannomas are rare lesions, representing 5– 10% of cranial nerve schwannomas. Management decisions should be individualized depending on tumor size, location and associated functional deficits. Generally, large sized schwannomas exerting significant mass effect with increased intracranial pressure are treated surgically. In some cases, even after optimal skull base resection, it is not possible to achieve a gross total resection because tumor location and extent and/or to reduce morbidity. Thus, subtotal resection followed by stereotactic radiosurgery or fractioned radiotherapy offers an alternative approach. In certain cases, stereotactic radiosurgery or radiotherapy alone achieves good tumor control rates and less morbidity to gross total resection. Finally, given the slow growth rate of most of these tumors, observation with periodic radiographic follow-up approach is also a reasonable alternative for small tumors with few, if any, symptoms.Keywords: schwannoma, head and neck, cranial nerves, non-vestibular, skull base

Surgery of the base of the skull requires knowledge of the topography of the internal carotid artery, cavernous sinus, cranial nerves of the sellyar and paraclinoid regions. Equally important is knowledge of the topography and structure of the dura mater (CSF) at the base of the skull, CSF duplicates, cerebellar ligaments, meningeal membranes (tank membranes of the brain base, carotid oculomotor membrane of the proximal carotid ring) and carotid rings in neurooncology and vascular neurosurgery. The article presents the results of the study of the structure of TMO in the selvary and paraselar regions.

Because of the inherent complex anatomy and functional arrangement of the cranial nerves (CNs), neuroimaging of cranial neuropathy is challenging. With recent advances in magnetic resonance imaging (MRI) techniques, the cause of cranial neuropathy can now be detected in many cases. As an active multidisciplinary team member of cranial neuropathy, it is essential for the neuroradiologist to be familiar with the detailed anatomy of the CNs on MRI. This review contains the basic MRI anatomy of CNs III–XII according to a segmental classification from the brain stem to the extracranial region. The optimal imaging options to best evaluate the specific segment of the CNs will also be discussed briefly.

Abstract Objective To estimate the prevalence and significance of cranial nerve (CN) imaging abnormalities in patients with hereditary neuropathy and discuss clinical implications. Methods We retrospectively analyzed data from patients at four tertiary academic medical centers with hereditary neuropathy diagnoses who had undergone gadolinium‐enhanced magnetic resonance imaging (MRI) of the brain or skull base between 2004 and 2018. MRI scans, as well as computed tomography imaging when available, were reviewed and bivariable analysis was performed to identify predictors of CN abnormalities on imaging. Results Among 39 patients meeting study criteria, 11 had clinical CN deficits (28%) and 8 had CN abnormalities on imaging (21%). Of the patients with CN abnormalities on imaging, half had CN deficits (4/8) and only a quarter had imaging abnormalities of the CNs with the deficits (2/8). Imaging abnormalities were found in varied CNs, including CNs III, V, VII, and the VII/VIII complex in the internal auditory canal. MRI obtained for the purpose of evaluating CN deficits had a statistically significant increased likelihood of containing CN imaging abnormalities. However, CN deficits themselves were not predictive of imaging abnormalities. Conclusion Thickening and enhancement of CNs on MRI may be found in approximately 1/5 of patients with hereditary neuropathies and are inconsistently associated with clinical deficits. These imaging findings should not be mistaken for neoplastic and infectious processes as they may be manifestations of the patients' underlying genetic neuropathy. Level of Evidence 4.

Perineural spread (PNS) represents the tumor’s ability to disseminate along nerves. The aim of this article is to review the relevant literature about the PNS in head and neck tumors (HN). The important information for imaging analysis is summarized in a diagnostic flow-chart. The pathogenesis, clinical signs, prognostic importance, and technical considerations for computer tomography and magnetic resonance imaging are briefly discussed. The anatomical pathways of the cranial nerves (CNs) and the main check-points are synthesized. Most commonly affected nerves are the trigeminal and facial, although any of the CNs may be involved. The described imaging features represent important clues for an optimal differential diagnosis. PNS worsens the prognosis and significantly changes the treatment, thus radiologists should be aware of this entity and be able to find it on imaging in the appropriate clinical context.

The involvement of cranial nerves is being increasingly recognised in COVID-19. This review aims to summarize and discuss the recent advances concerning the clinical presentation, pathophysiology, diagnosis, treatment, and outcomes of SARS-CoV-2 associated cranial nerve mononeuropathies or polyneuropathies. Therefore, a systematic review of articles from PubMed and Google Scholar was conducted. Altogether 36 articles regarding SARS-CoV-2 associated neuropathy of cranial nerves describing 56 patients were retrieved. Out of these 56 patients, cranial nerves were compromised without the involvement of peripheral nerves in 32 of the patients, while Guillain-Barre syndrome (GBS) with cranial nerve involvement was described in 24 patients. A single cranial nerve was involved either unilaterally or bilaterally in 36 patients, while in 19 patients multiple cranial nerves were involved. Bilateral involvement was more prevalent in the GBS group (n=11) as compared to the cohort with isolated cranial nerve involvement (n=5). Treatment of cranial nerve neuropathy included steroids (n=18), intravenous immunoglobulins (IVIG) (n=18), acyclovir/valacyclovir (n=3), and plasma exchange (n=1). The outcome was classified as “complete recovery” in 21 patients and as ”partial recovery” in 30 patients. One patient had a lethal outcome. In conclusion, any cranial nerve can be involved in COVID-19, but cranial nerves VII, VI, and III are the most frequently affected. The involvement of cranial nerves in COVID-19 may or may not be associated with GBS. In patients with cranial nerve involvement, COVID-19 infections are usually mild. Isolated cranial nerve palsy without GBS usually responds favorably to steroids. Cranial nerve involvement with GBS benefits from IVIG.

Introduction: The evolution of cavernous sinus meningiomas (CSMs) might be unpredictable and the efficacy of their treatments is challenging due to their indolent evolution, variations and fluctuations of symptoms, heterogeneity of classifications and lack of randomized controlled trials. Here, a dedicated task force provides a consensus statement on the overall management of CSMs. Research question: To determine the best overall management of CSMs, depending on their clinical presentation, size, and evolution as well as patient characteristics. Material and methods: Using the PRISMA 2020 guidelines, we included literature from January 2000 to December 2020. A total of 400 abstracts and 77 titles were kept for full-paper screening. Results: The task force formulated 8 recommendations (Level C evidence). CSMs should be managed by a highly specialized multidisciplinary team. The initial evaluation of patients includes clinical, ophthalmological, endocrinological and radiological assessment. Treatment of CSM should involve experienced skull-base neurosurgeons or neuro-radiosurgeons, radiation oncologists, radiologists, ophthalmologists, and endocrinologists. Discussion and conclusion: Radiosurgery is preferred as first-line treatment in small, enclosed, pauci-symptomatic lesions/in elderly patients, while large CSMs not amenable to resection or WHO grade II-III are candidates for radiotherapy. Microsurgery is an option in aggressive/rapidly progressing lesions in young patients presenting with oculomotor/visual/endocrinological impairment. Whenever surgery is offered, open cranial approaches are the current standard. There is limited experience reported about endoscopic endonasal approach for CSMs and the main indication is decompression of the cavernous sinus to improve symptoms. Whenever surgery is indicated, the current trend is to offer decompression followed by radiosurgery.

Aim. CEAE is an effective method of ischemic stroke prevention. However, as any invasive treatment method, CEAE is associated with a risk of complications in the early and late postoperative periods. One of the possible complications is intraoperative injury of cranial nerves.Material and Methods. From 2008 to 2014 in the department of vascular surgery in Pletnev City Hospital in Moscow, 172 patients with hemodynamically significant ICA stenosis who suffered ischemic stroke or TIA underwent surgery.Results. In the early postoperative period, 7 episodes of cranial nerve injury (4.0%) were detected. The following cranial nerves were most often damaged during surgery: the terminal branches of the facial nerve (VII), the hypoglossus nerve (XII), the glossopharyngeal nerve (IX), and the vagus nerve (X). Injuries were associated with coagulation damage or compression of nerves. In one case, the intersection of the hypoglossus nerve was recorded. In all cases except this one, nerve damage was reversible.Conclusion. It is impossible to avoid cranial nerves injury during carotid endarterectomy. However, the number of such complications can be reduced by the measures described in this article.

Abstract Occipital condylar fractures (OCFs) causing delayed onset lower cranial nerve paralysis (LCNPs) are rare. We present a 7‐year‐old Friesian horse with delayed onset dysphagia caused by vagus nerve (CNX) paralysis and suspicion of glossopharyngeal nerve (CNIX) paralysis developed several days after a minor head injury. Endoscopic examination revealed right laryngeal hemiplegia and intermittent dorsal displacement of the soft palate. An area of submucosal hemorrhage and bulging was appreciated over the dorsal aspect of the medial compartment of the right guttural pouch. Radiological examination of the proximal cervical region showed rotation of the atlas and the presence of a large bone fragment dorsal to the guttural pouches. Occipital condyle fracture with delayed onset cranial nerve paralysis was diagnosed. Delayed onset cranial nerve paralysis causing dysphagia might be a distinguishable sign of OCF in horses. Delayed onset dysphagia after head injury should prompt equine clinicians to evaluate the condition of the atlanto‐occipital articulation and skull base.

Abstract Background With increasing treatment options available, neuroendocrine tumor has become a chronic disease and may present later on with atypical manifestation of disease spread once resistant to treatment. Case presentation A 74-year-old white British woman undergoing treatment for metastatic well-differentiated neuroendocrine tumor for the past 9 years presented with a brief history of mild frontal headache, and progressive left ptosis and ocular palsy. She had no visual loss, and had neither speech nor motor deficit. At the outset, it was crucial to exclude acute or missed stroke. An urgent magnetic resonance imaging of her head revealed an unusual skull base metastasis extending into the cavernous sinus, with no peritumoral edema. Following discussion at a specialist neuro-oncology meeting and a neuroendocrine tumor multidisciplinary team meeting, she proceeded to have conventional fractionated radiotherapy followed by subsequent palliative chemotherapy. Conclusions Intracranial metastasis is rare in patients with neuroendocrine tumor, particularly in those with well-differentiated histology; skull base metastasis is even more uncommon. Management of intracranial metastasis from a rare tumor should always be discussed in a specialist multidisciplinary meeting. Surgery or radiotherapy, including stereotactic radiosurgery, should be considered in skull base metastases. Hormonal abnormalities may occur following radiotherapy to skull base metastases and should be monitored closely in the first few months post treatment.

Abstract The human body has 12 pairs of cranial nerves that control motor and sensory functions of the head and neck. The anatomy of cranial nerves is complex and its knowledge is crucial to detect pathological alterations in case of nervous disorders. Therefore, it is necessary to know the most frequent pathologies that may involve cranial nerves and recognize their typical characteristics of imaging. Cranial nerve dysfunctions may be the result of pathological processes of the cranial nerve itself or be related to tumors, inflammation, infectious processes, or traumatic injuries of adjacent structures. Magnetic resonance imaging (MRI) is considered the gold standard in the study of the cranial nerves. Computed tomography (CT) allows, usually, an indirect view of the nerve and is useful to demonstrate the intraosseous segments of cranial nerves, the foramina through which they exit skull base and their pathologic changes. The article is a complete pictorial overview of the imaging of cranial nerves, with anatomic and pathologic descriptions and great attention to illustrative depiction. We believe that it could be a useful guide for radiologists and neuroradiologists to review the anatomy and the most important pathologies that involve cranial nerves and their differential diagnosis.

Introduction Jugular foramen is one of the most fascinating foramina of the human skull. It is a complex, irregular bony canal located between the occipital bone and petrous part of the temporal bone. Many important structures, like 9th, 10th, 11th cranial nerves, meningeal branch of occipital and ascending pharyngeal arteries, internal jugular vein, and inferior petrosal sinus, are passing through it. The jugular fossa has a septum and a dome. The septum divides the foramen into two compartments: anteromedial compartment (pars nervosa) and posterolateral compartment (pars vascularis). The dome contains superior bulb of internal j’ugular vein. The architecture of the foramen varies in size, shape, and laterality besides differences related to sex and race. The morphometric measurements of j’ugular foramen are very important for neurosurgeries and head and neck surgeries. Objectives The aim of the present study is to study the morphology of jugular foramen along with its dimensions, compartments, presence of partial or complete septa and dome. Materials and Methods A total number of 60 jugular foramina were examined from 30 adult dry human skulls of unknown age and sex from the Department of Anatomy, PSG Institute of Medical Sciences and Research, Coimbatore. Measurements were taken using Digital Vernier calipers. Results were analyzed statistically. Results The length, width, and surface area of jugular foramen of right side were measured and compared with the left side. Length and width of the jugular foramen was significantly higher on the right side. The presence of partial septum was found in 27 skulls (90%) on the right side and 29 skulls (99.7%) on the left side, respectively. Dome was present in 100% of the jugular foramina on the right side and 90% of the jugular foramina on the left side. Separate opening for inferior petrosal sinus was found in eight skulls (27%) on the right side and four skulls (13%) on the left side. Conclusion This study provides a clear understanding of anatomy of jugular foramen and supports the reported morphometric variations. The morphometric variations of jugular foramen in the parameters of the skull are probably due to ethnic and racial factors. Knowledge of these variations is important for neurosurgeons and radiologists who deal with space occupying lesions of the structures surrounding jugular foramen. This study may be helpful for ENT surgeons while performing middle ear surgeries.

Abstract The glossopharyngeal nerve (GPN) is a rarely considered cranial nerve in imaging interpretation, mainly because clinical signs may remain unnoticed, but also due to its complex anatomy and inconspicuousness in conventional cross-sectional imaging. In this pictorial review, we aim to conduct a comprehensive review of the GPN anatomy from its origin in the central nervous system to peripheral target organs. Because the nerve cannot be visualised with conventional imaging examinations for most of its course, we will focus on the most relevant anatomical references along the entire GPN pathway, which will be divided into the brain stem, cisternal, cranial base (to which we will add the parasympathetic pathway leaving the main trunk of the GPN at the cranial base) and cervical segments. For that purpose, we will take advantage of cadaveric slices and dissections, our own developed drawings and schemes, and computed tomography (CT) and magnetic resonance imaging (MRI) cross-sectional images from our hospital’s radiological information system and picture and archiving communication system. Teaching Points • The glossopharyngeal nerve is one of the most hidden cranial nerves. • It conveys sensory, visceral, taste, parasympathetic and motor information. • Radiologists’ knowledge must go beyond the limitations of conventional imaging techniques. • The nerve’s pathway involves the brain stem, cisternal, skull base and cervical segments. • Systematising anatomical references will help with nerve pathway tracking.

For years, generations of medical students were taught that in stroke, “;In a upper motor neuron (UMN) lesion, the upper part of the face is spared because this part of the face has bilateral representation while in a lower motor neuron (LMN) lesion, both parts of the face are involved.” Is this explanation apt ? Most of the fibers of the corticospinal tract decussate to the opposite side. But only 50% of the corticobulbar fibers decussate, meaning the muscles they supply receive fibers from both motor cortex (bilateral representation). Bilateral representation in the cortex is a perfect example of symmetry in the human body. An exception to this rule would be the lower part of the face which receives fibers from the contralateral cortex alone (unilateral representation). This goes against the general rule and so this represents the first paradox of the cranial nerves. The second paradox is entirely man made and is reversible. Should it not be, “;In a UMN lesion of the facial nerve, only the contralateral lower half of the face is affected, because this part of the face has unilateral representation only” and not “;In a UMN lesion of the facial nerve, the contralateral upper part of the face is spared because this part of the face has bilateral representation.” After all, is not bilateral representation the rule and unilateral representation the exception ?.

Background and objectives: A flipped classroom concept involves inverting the classroom teaching activities. Here, the learner learns the ‘core’ concepts before the class, usually at home, reading and watching an online video, at his will. The aim of current study was to evaluate the effectiveness of flipped classroom for teaching concepts in anatomy. The subject chosen was cranial nerves. Methodology: Ninety-two students participated in this study. Four topics from cranial nerves were selected for the project. Regular lecture classes were taken for first two topics. Flipped classroom was used for the next two. Videos intended for flipped classroom were made available to all students through WhatsApp platform and blog post 48 hours prior to class. Assessment was by MCQs - 25 from topics covered by conventional method and 25 from flipped classroom topics. Score of 50% was considered as pass. Number of students in pass and fail category were compared through chi- square test. Results: Mean scores after regular and flipped classes were 12.92 (SD ± 3.13) and 13.41 (SD ± 3.38) respectively. Fifty eight students passed after flipped classroom teaching and 47 students passed after regular class. The number of students passing after flipped class as compared to regular class is statistically significant. Perceptive rating of flipped classroom concept was 4.15 out of 5 in comparison to traditional methods. Conclusion: Flipped classroom is effective in learning anatomy. Studies pursued for longer duration with broader subject coverage are suggested.

History of present illness: A 53-year-old male presents to a local community emergency department complaining of sore throat, difficulty swallowing, hoarseness of voice and odynophagia progressively worsening for 5 days. He states symptoms started two weeks ago with intractable hiccups and a bitter taste in the back of his tongue when eating. At that time, he saw his primary care provider and was subsequently prescribed chlorpromazine and omeprazole for presumed gastroesophageal reflux. His symptoms improved transiently, but then started to have difficulty swallowing his own secretions, at which point he presented to the emergency department. Significant findings: On exam, the patient was sitting upright while holding an emesis basin filled with saliva. His voice was noticeably hoarse. Examination of the head and neck revealed vesicular eruptions on the left scalp in the V1 dermatome and on the left mastoid process (Images 1 and 2). Physical exam also shows vesicular eruptions on the left posterior oropharynx that did not cross midline (Image 3). There was also a mass seen in the left peritonsillar area suspicious for peritonsillar abscess. There was slight deviation of the uvular to the right. His vital signs were temperature of 99.0F; heart rate, 75 beats/min; blood pressure, 135/80 mm Hg; and respiratory rate, 16 breaths/min. Oxygen saturation was 99% on room air. Due to concern for deep neck space infection, a computed tomography (CT) scan of the neck and soft tissue was done with intravenous (IV) contrast. The CT neck with IV contrast (image 4) shows a left parapharyngeal mass causing mild airway shift to the right. The mass measures approximately 5cm in length and 2cm in diameter. Radiology commented this is most likely an inflammatory process of the peritonsillar tissue, but he could not rule out a malignant process. Discussion: A clinical diagnosis of Varicella zoster virus (VZV) was made based on the skin findings. In this case the glossopharyngeal (cranial nerve 9), vagal (cranial nerve 10), 2ndand 3rdcervical nerves (C2, C3) were affected. Glossopharyngeal zoster will cause odynophagia, dysgeusia, and loss of the ipsilateral gag reflex.6 Vagal nerve zoster causes hoarseness of voice, difficulty swallowing, and rarely, intractable hiccups. During hiccups, the afferent nerve pathway travels along the vagus and phrenic nerve fibers. The phrenic nerve (C3-C5) serves as the primary efferent pathway.4 Our patient presented with odynophagia and dysgeusia in relation to cranial nerve (CN) 9 as well as hoarseness and intractable hiccups in relation to CN10. The mass-occupying lesion seen on CT is adjacent to the left external carotid and internal jugular veins. This most likely represents inflammatory swelling of CN 10, which passes anatomically through the carotid sheath. Herpes occipitocollaris (vertebral nerves C2 and C3) involves the posterior scalp, mastoid process, and auricle.7 Branches of these nerves communicate with CN 7 and CN 10, often causing symptoms related to these nerves as well. Disseminated zoster is defined as 20 or more vesicles outside of the primary and adjacent dermatomes, which our patient did not have.8 Our patient’s dysphagia was likely due to a combination of CN 9 palsy and pain from the peritonsillar mass. Given the degree of dysphagia and complaint of bitter taste sensation in the posterior tongue, CN 9 was most likely involved.6 His hiccups were a prodromal symptom of zoster infection caused by vagal nerve irritation. To date only six cases are documented.4 The diagnosis is difficult to make if the dermatologic manifestations are not apparent early on in the disease process. This patient was treated with 125mg IV solumedrol, 60mg intramuscular (IM) ketorolac, and 4mg IV morphine. After treatment, the patient’s pain improved and was able to tolerate PO intake and handle secretions. Otolaryngology (ENT) was consulted and recommended the patient be discharged home with valacyclovir 1g orally twice daily, prednisone 40mg orally daily, and 4% viscous lidocaine with follow up in two days. When speaking with ENT months later, I was informed the patient continued to improve with medical treatment and symptoms had fully resolved. A repeat CT was not done due to resolution of symptoms attributed to acute zoster infection. Topics: Herpes Zoster, infectious disease, cranial nerves, head and neck