Novel classification of foramen magnum meningiomas predicted by topographic position relative to neurovascular bundle

PURPOSE

Proximity to critical neurovascular structures can create significant obstacles during surgical resection of foramen magnum meningiomas (FMMs) to the detriment of treatment outcomes. We propose a new classification that defines the tumor's relationship to neurovascular structures and assess correlation with postoperative outcomes.

METHODS

In this retrospective review, 41 consecutive patients underwent primary resection of FMMs through a far lateral approach. Groups defined based on tumor-neurovascular bundle configuration included Type 1, bundle ventral to tumor; Type 2a-c, bundle superior, inferior, or splayed, respectively; Type 3, bundle dorsal; and Type 4, nerves and/or vertebral artery encased by tumor.

RESULTS

The 41 patients (range 29-81 years old) had maximal tumor diameter averaging 30.1 mm (range 12.7-56 mm). Preoperatively, 17 (41%) patients had cranial nerve (CN) dysfunction, 12 (29%) had motor weakness and/or myelopathy, and 9 (22%) had sensory deficits. Tumor type was relevant to surgical outcomes: specifically, Type 4 demonstrated lower rates of gross total resection (65%) and worse immediate postoperative CN outcomes. Long-term findings showed Types 2, 3, and 4 demonstrated higher rates of permanent cranial neuropathy. Although patients with Type 4 tumors had overall higher ICU and hospital length of stay, there was no difference in tumor configuration and rates of postoperative complications or 30-day readmission.

CONCLUSION

The four main types of FMMs in this proposed classification reflected a gradual increase in surgical difficulty and worse outcomes. Further studies are warranted in larger cohorts to confirm its reliability in predicting postoperative outcomes and possibly directing management decisions.

Acute peripheral facial paralysis caused by tegmental pontine infarction

Facial paralysis presents as unilateral mouth drooping and lagophthalmos. The main causes of peripheral facial paralysis are Bell's palsy and Ramsay-Hunt syndrome. However, rarely occurring pontine infarctions of the facial nucleus also manifest a lower motor neuron pattern of facial paralysis. We report a case of a man in his 50s who presented to the emergency department with unilateral peripheral facial paralysis. The initial diffusion-weighted images were unremarkable, and the patient was managed as per guidelines for hypertensive encephalopathy or Bell's palsy. On the 3rd day after admission, he was diagnosed with left pontine infarction and suspected infarction of the left anterior inferior cerebellar artery. We propose that in similar cases, re-examination of imaging results should be considered, as diffusion-weighted imaging is characteristically prone to generate false-negative results in patients with early onset or posterior circulation infarction.

Herpes zoster of posterior division of mandibular branch of trigeminal nerve

Herpes zoster is a disease caused by the reactivation of dormant varicella zoster virus present in the sensory root ganglion. It presents with a vesicular rash on an erythematous base similar to that seen in classical varicella, however, with only a single dermatomal distribution. The rash is usually seen throughout the affected dermatome as the dorsal root ganglia for each dermatome are clustered together. We present a case of an otherwise healthy male who developed a vesicular rash confined to the distribution of the posterior division of the mandibular nerve. Though the entire mandibular nerve arises from a single ganglion, the skin area supplied by the anterior division of the mandibular nerve was spared. This case provides evidence to show that there is anatomic segregation of cell bodies of nerves traversing anterior and posterior divisions of mandibular division in the trigeminal ganglion and that partial involvement of a sensory root ganglion is possible in immunocompetent patients.

Extracranial transport of brain lymphatics via cranial nerve in human

Extracranial waste transport from the brain interstitial fluid to the deep cervical lymph node (dCLN) is not extensively understood. The present study aims to show the cranial nerves that have a role in the transport of brain lymphatics vessels (LVs), their localization, diameter, and number using podoplanin (PDPN) and CD31 immunohistochemistry (IHC) and Western blotting. Cranial nerve samples from 6 human cases (3 cadavers, and 3 autopsies) were evaluated for IHC and 3 autopsies for Western blotting. The IHC staining showed LVs along the optic, olfactory, oculomotor, trigeminal, facial, glossopharyngeal, accessory, and vagus nerves. However, no LVs present along the trochlear, abducens, vestibulocochlear, and hypoglossal nerves. The LVs were predominantly localized at the endoneurium of the cranial nerve that has motor components, and LVs in the cranial nerves that had sensory components were present in all 3 layers. The number of LVs accompanying the olfactory, optic, and trigeminal nerves was classified as numerous; oculomotor, glossopharyngeal, vagus, and accessory was moderate; and facial nerves was few. The largest diameter of LVs was in the epineurium and the smallest one was in the endoneurium. The majority of Western blotting results correlated with the IHC. The present findings suggest that specific cranial nerves with variable quantities provide a pathway for the transport of wastes from the brain to dCLN. Thus, the knowledge of the transport of brain lymphatics along cranial nerves may help understand the pathophysiology of various neurological diseases.

MRI evaluation of cranial nerve abnormalities and extraocular muscle fibrosis in duane retraction syndrome and congenital extraocular muscle fibrosis

PURPOSE

To investigate the alterations in extraocular muscles (EOMs) by magnetic resonance imaging (MRI) among patients diagnosed with Duane retraction yndrome (DRS) and congenital fibrosis of the extraocular muscles (CFEOM), who present with various cranial nerve anomalies in an attempt to enhance the clinical diagnostic process.

METHODS

A case-control study was conducted to evaluate 27 patients with DRS and 14 patients with CFEOM. All patients underwent MRI scans of the brainstem and orbital examination. Neurodevelopmental assessments were conducted through MRI, and maximum cross-sectional area and volumes of EOMs were obtained. Three types of models were constructed using machine learning decision tree algorithms based on EOMs to predict disease diagnosis, cranial nerve abnormalities, and clinical subtypes.

RESULTS

Patients with bilateral CN VI abnormalities had smaller volumes of LR, MR, and IR muscles compared to those with unilateral involvement (P < 0.05). Similarly, patients with CFEOM and unilateral third cranial nerve abnormalities had a smaller maximum cross-section of the affected eye's SR compared to the contralateral eye (P < 0.05). In patients with both CN III and CN VI abnormalities, the volume of SR was smaller than in patients with CN III abnormalities alone (P < 0.05). The prediction model using EOMs volume showed a diagnostic precision of 82.5% for clinical cases and 60.1% for predicting cranial nerve abnormalities. Nonetheless, the precision for identifying clinical subtypes was relatively modest, at only 41.7%.

CONCLUSION

The distinctive volumetric alterations in EOMs among individuals exhibiting distinct cranial nerve anomalies associated with DRS or CFEOM provide valuable diagnostic insights into to Congenital Cranial Neurodevelopmental Disorders (CCDDs). MRI analysis of EOMs should thus be regarded as a crucial diagnostic modality.

Presentation of basilar artery stroke secondary to patent foramen ovale: a diagnosis made with a 'selfie'

We report the case of a woman in her late 20s, with no significant medical history, who was found unresponsive at home. Her mother revealed a 'selfie' sent to her by the patient 30 min prior to collapse which revealed bilateral ptoses. Initial brain imaging with non-contrast CT of the brain revealed nil of note. A multiphase CT angiogram revealed an acute basilar artery thrombosis. She underwent timely thrombolysis and was transferred for endovascular thrombectomy. Further evaluation with an aim to define the aetiology revealed the diagnosis of patent foramen ovale with a resultant paradoxical embolism. The differential diagnoses of unexplained rapidly evolving neurology with reduced Glasgow coma scale, and relevant appropriate investigations are discussed in this case report.

Case of infiltrative optic neuropathy with hypertrophic pachymeningitis as a manifestation of en plaque meningioma

We describe a case of infiltrative optic neuropathy with hypertrophic pachymeningitis noted on MRI of the brain, presenting a diagnostic dilemma with a wide variety of differential diagnoses to consider. Our patient is a middle-aged woman with a 20-year history of migranous-sounding headaches who was incidentally found to have worsening vision in her left eye during a routine driving test visual acuity check. Neurological examination revealed a left grade III relative afferent pupillary defect and a central scotoma with red desaturation. Subsequent MRI of her brain and anterior visual pathway revealed features suggestive of an infiltrative left optic neuropathy with hypertrophic pachymeningitis. An extended workup including diagnostic lumbar puncture and blood tests for possible autoimmune, infective and neoplastic causes proved unyielding. Eventually, an endoscopic transsphenoidal biopsy helped to clinch the diagnosis of a (meningothelial subtype) WHO grade 1 meningioma as the cause of her clinical and radiological presentation.

Somatosensory input in the context of transcranial magnetic stimulation coupled with electroencephalography: An evidence-based overview

The transcranial evoked potential (TEP) is a powerful technique to investigate brain dynamics, but some methodological issues limit its interpretation. A possible contamination of the TEP by electroencephalographic (EEG) responses evoked by the somatosensory input generated by transcranial magnetic stimulation (TMS) has been postulated; nonetheless, a characterization of these responses is lacking. The aim of this work was to review current evidence about possible somatosensory evoked potentials (SEP) induced by sources of somatosensory input in the craniofacial region. Among these, only contraction of craniofacial muscle and stimulation of free cutaneous nerve endings may be able to induce EEG responses, but direct evidence is lacking due to experimental difficulties in isolating these inputs. Notably, EEG evoked activity in this context is represented by a N100/P200 complex, reflecting a saliency-related multimodal response, rather than specific activation of the primary somatosensory cortex. Strategies to minimize or remove these responses by EEG processing still yield uncertain results; therefore, data inspection is of paramount importance to judge a possible contamination of the TEP by multimodal potentials caused by somatosensory input.

Unmasking the Common Thief: A Rare Cause of Isolated Hypoglossal Nerve Palsy

Multiple cranial nerve palsies frequently accompany hypoglossal nerve palsy, potentially indicating malignancy, such as lymphoma, nasopharyngeal carcinoma, or metastases. However, when solely the hypoglossal nerve is affected, the causes may involve Chiari malformation, arachnoid cyst, or infectious mononucleosis, suggesting a positive prognosis. Craniocervical junction tuberculosis (TB), is an uncommon cause of isolated hypoglossal nerve palsy and has been reported infrequently in the literature. Craniocervical junction tuberculosis accounts for only 0.5% of TB cases overall and 6% of extra-pulmonary TB cases. We present here one such case of a 17-year-old male of Indian origin with a subacute history of tongue deviation and neck pain. Additionally, the patient reported loss of weight and appetite. The patient had significant posterior cervical lymphadenopathy. Neurological examination revealed findings suggestive of right peripheral hypoglossal nerve involvement. Blood investigations showed lymphocytosis along with an elevated erythrocyte sedimentation rate of 45 mm/h and elevated lactate dehydrogenase levels of 325 U/L. Tuberculin skin testing was positive and sputum acid-fast staining confirmed acid-fast bacilli. Magnetic Resonance Imaging of the cervical spine revealed a soft tissue component in the prevertebral space measuring 3.5×4.8 cm with a right paraspinal component adjoining the hypoglossal canal with peripheral contrast enhancement. Histological findings on the lymph node showed granulomatous lymphadenitis, suggestive of tuberculosis. The patient was started on 4-drug anti-tubercular therapy consisting of Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol for a period of 18 months. He was subsequently followed up for 6 months till the resolution of palsy. This case emphasizes the importance of thorough evaluation and a meticulous workup to identify the underlying cause of hypoglossal nerve palsy and the importance of considering tuberculosis as a potential cause of isolated hypoglossal nerve palsy in everyday practice.

Isolated neurosarcoidosis with a primary lesion in the cauda equina

A man in his late 50s without notable medical background was admitted with subacute onset of bilateral lower extremity weakness. Blood and physiological examinations revealed no significant abnormalities. Cerebrospinal fluid (CSF) examination revealed elevated cell count and protein levels and an immunoglobulin G index of 2.01. T1-weighted MRI showed swelling and enhancement of the cauda equina. After admission, the patient developed bowel and bladder incontinence, deteriorated to manual muscle test 0 and developed right trochlear, trigeminal and facial nerve palsy. He underwent a cauda equina biopsy and was diagnosed with neurosarcoidosis. After methylprednisolone pulse therapy and corticosteroid treatment, cauda equina syndrome including lower extremity weakness and cerebral nerve palsy improved. The patient's daily activities improved to the baseline level over 2 months after discharge. Serum and CSF soluble interleukin-2 receptor levels were within the reference range and decreased with the improvement of neurological and imaging findings.

Diffusion MRI of the facial-vestibulocochlear nerve complex: a prospective clinical validation study

OBJECTIVES

Surgical planning of vestibular schwannoma surgery would benefit greatly from a robust method of delineating the facial-vestibulocochlear nerve complex with respect to the tumour. This study aimed to optimise a multi-shell readout-segmented diffusion-weighted imaging (rs-DWI) protocol and develop a novel post-processing pipeline to delineate the facial-vestibulocochlear complex within the skull base region, evaluating its accuracy intraoperatively using neuronavigation and tracked electrophysiological recordings.

METHODS

In a prospective study of five healthy volunteers and five patients who underwent vestibular schwannoma surgery, rs-DWI was performed and colour tissue maps (CTM) and probabilistic tractography of the cranial nerves were generated. In patients, the average symmetric surface distance (ASSD) and 95% Hausdorff distance (HD-95) were calculated with reference to the neuroradiologist-approved facial nerve segmentation. The accuracy of patient results was assessed intraoperatively using neuronavigation and tracked electrophysiological recordings.

RESULTS

Using CTM alone, the facial-vestibulocochlear complex of healthy volunteer subjects was visualised on 9/10 sides. CTM were generated in all 5 patients with vestibular schwannoma enabling the facial nerve to be accurately identified preoperatively. The mean ASSD between the annotators' two segmentations was 1.11 mm (SD 0.40) and the mean HD-95 was 4.62 mm (SD 1.78). The median distance from the nerve segmentation to a positive stimulation point was 1.21 mm (IQR 0.81-3.27 mm) and 2.03 mm (IQR 0.99-3.84 mm) for the two annotators, respectively.

CONCLUSIONS

rs-DWI may be used to acquire dMRI data of the cranial nerves within the posterior fossa.

CLINICAL RELEVANCE STATEMENT

Readout-segmented diffusion-weighted imaging and colour tissue mapping provide 1-2 mm spatially accurate imaging of the facial-vestibulocochlear nerve complex, enabling accurate preoperative localisation of the facial nerve. This study evaluated the technique in 5 healthy volunteers and 5 patients with vestibular schwannoma.

KEY POINTS

• Readout-segmented diffusion-weighted imaging (rs-DWI) with colour tissue mapping (CTM) visualised the facial-vestibulocochlear nerve complex on 9/10 sides in 5 healthy volunteer subjects. • Using rs-DWI and CTM, the facial nerve was visualised in all 5 patients with vestibular schwannoma and within 1.21-2.03 mm of the nerve's true intraoperative location. • Reproducible results were obtained on different scanners.

Acute Cranial Nerve VI Palsy Following Prolonged Prone Positioning in an Adolescent With Neurofibromatosis Type 1: A Rare Complication of Spinal Surgery in the Prone Position

The abducens or sixth cranial nerve provides motor innervation to the lateral rectus muscle, which abducts the ipsilateral eye with secondary innervation of the contralateral medial rectus muscle to allow for coordinated movement of both eyes. Various acute and chronic pathologic conditions, most importantly pontine infarctions and increased intracranial pressure, can result in acute sixth cranial nerve palsies. We report the uncommon occurrence of acute abducens nerve palsy following spinal fusion surgery in an 18-year-old male patient with a history of multiple neurological and orthopedic conditions. Postoperatively, the patient presented with symptoms that included left diplopia with restricted upward and downward gaze, indicative of abducens nerve palsy. The anatomy of the sixth cranial nerve is discussed, potential etiologies of sixth nerve palsy presented, and a proposed diagnostic workup reviewed. Our report emphasizes the need for comprehensive exploration of ocular symptoms following spinal surgery, given the various potential etiologies of sixth nerve palsy.

Extradural disconnection of the cavernous sinus with preservation of the internal carotid artery: indication and technique

BACKGROUND

Extradural disconnection of the cavernous sinus (CS) with preservation of the internal carotid artery (ICA) is indicated for aggressive and recurrent tumors, in patients presenting loss of oculomotor function and non-functional circle of Willis.

METHOD

Extradural resection of the anterior clinoid process disconnects the CS anteriorly. The ICA is dissected in the foramen lacerum via extradural subtemporal approach. The intracavernous tumor is split and removed following the ICA. Bleeding control of the inferior and superior petrosal and intercavernous sinuses completes posterior CS disconnection.

CONCLUSION

This technique can be proposed for recurrent CS tumors and need of ICA preservation.

A Patient with Refractory Trigeminal Neuralgia was Referred for Suspected Odontogenic Pain

Chronic pain of the face with a sudden, unilateral, and electric shock-like pain in the distribution of the trigeminal nerve is known as Trigeminal neuralgia (TN). This case report presents a patient with TN symptoms, along with concomitant tooth pain. The diagnostic process and management of the patient are discussed, emphasizing the importance of interdisciplinary collaboration for optimal patient care.

Cranial nerve VI palsy in chronic sphenoid sinusitis

Sphenoid sinusitis is a rare disease associated with life-threatening complications that can be avoided with early recognition and timely treatment. Here, we present a case of a woman in her 80s admitted for symptomatic anaemia likely secondary to a gastrointestinal bleed with left cranial nerve (CN) VI palsy incidentally discovered on physical examination. CT and MRI were suggestive of chronic left sphenoid sinusitis with possible involvement of the left cavernous sinus. Surgical treatment was deferred due to high cardiac risk for perioperative mortality and recent ischaemic stroke. Despite antibiotic treatment, the patient's CN VI palsy remained unchanged. This report contributes to the current understanding of sphenoid sinusitis by presenting a complex case of chronic sphenoid sinusitis in which urgent surgical intervention was deferred due to the patient's multiple comorbidities. Furthermore, it highlighted the importance of the CN examination and imaging modalities in diagnosing sphenoid sinusitis.

Topography of cranial foramina and anaesthesia techniques of cranial nerves in selected species of primates (Cebidae, Cercopithecidae, Lemuridae) - part I - osteology

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.

The rule of five: A novel anatomical landmark for approaching cavernous sinus content

BACKGROUND

The main objective of this study is to enhance neurosurgeons' anatomical knowledge by providing specific anatomical references of the cavernous sinus (CS). However, it is essential to clarify that our study does not seek to establish an absolute intraoperative rule due to the inherent anatomical variability that must be considered.

METHODS

Fifty-three cadaveric specimens were procured from the Forensic Institute (Bogotá) and subjected to dissection through an extradural approach. The measurements were taken in two distinct phases. The first phase involved the measurement of various anatomical structures in 25 specimens with respect to the anterior and posterior clinoids. The second phase, which was conducted 5 years later, involved the measurement of the distance between the foramen rotundum and the foramen ovale in 28 specimens using the L&W tools microcaliper.

RESULTS

In 25 specimens, a perpendicular imaginary line was drawn from the lateral tip of the anterior clinoid to the floor of the medial fossa. This facilitated access to the Parkinson's triangle, which is located between the IV cranial nerve and the ophthalmic V1 nerve, revealing a constant distance of 5 mm between the lateral tip of the anterior clinoid and the IV cranial nerve. Furthermore, in 28 specimens, the mean distance from the foramen rotundum to the foramen ovale was found to be 1.3 cm bilaterally.

CONCLUSION

The rule of five is a valuable tool for comprehensively understanding the anatomy of the CS, providing a reference point for the different normal anatomical structures within the CS.

Stylohyoid fracture resulting in facial paralysis

A female patient in her early 30s was referred to the otology clinic for progressive left facial paralysis. Two weeks prior to the onset of the paralysis, she had heard a loud cracking sound when drinking water. A CT scan showed a left styloid fracture near the stylomastoid foramen, compressing the facial nerve. Varicella IgG and IgM were negative, but the patient was started on a tapering course of steroids and valacyclovir. Approximately 1 month after the original incident, her left facial nerve paralysis improved. This report describes the unusual cause of facial paralysis and discusses the importance of history taking and imaging studies.

Bilateral vocal cord palsy as complication of CNS tuberculosis

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.

Skull base osteomyelitis: A case report of Garcin syndrome due to mucormycosis in COVID pandemic

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.

Probabilistic tractography of the extracranial branches of the trigeminal nerve using diffusion tensor imaging

PURPOSE

The peripheral course of the trigeminal nerves is complex and spans multiple bony foramen and tissue compartments throughout the face. Diffusion tensor imaging of these nerves is difficult due to the complex tissue interfaces and relatively low MR signal. The purpose of this work is to develop a method for reliable diffusion tensor imaging-based fiber tracking of the peripheral branches of the trigeminal nerve.

METHODS

We prospectively acquired imaging data from six healthy adult participants with a 3.0-Tesla system, including T2-weighted short tau inversion recovery with variable flip angle (T2-STIR-SPACE) and readout segmented echo planar diffusion weighted imaging sequences. Probabilistic tractography of the ophthalmic, infraorbital, lingual, and inferior alveolar nerves was performed manually and assessed by two observers who determined whether the fiber tracts reached defined anatomical landmarks using the T2-STIR-SPACE volume.

RESULTS

All nerves in all subjects were tracked beyond the trigeminal ganglion. Tracts in the inferior alveolar and ophthalmic nerve exhibited the strongest signal and most consistently reached the most distal landmark (58% and 67%, respectively). All tracts of the inferior alveolar and ophthalmic nerve extended beyond their respective third benchmarks. Tracts of the infraorbital nerve and lingual nerve were comparably lower-signal and did not consistently reach the furthest benchmarks (9% and 17%, respectively).

CONCLUSION

This work demonstrates a method for consistently identifying and tracking the major nerve branches of the trigeminal nerve with diffusion tensor imaging.

Idiopathic hypertrophic pachymeningitis in a patient with a history of diffuse large B cell lymphoma

A man in his early 70s with a 4-year history of diffuse large B cell lymphoma (DLBCL) was admitted to our hospital with diplopia and achromatopsia. Neurological examination revealed visual impairment, ocular motility disorder and diplopia on looking to the left. Blood and cerebrospinal fluid investigations showed no significant findings. MRI revealed diffusely thickened dura mater and contrast-enhanced structures in the left apical orbit, consistent with hypertrophic pachymeningitis (HP). We performed an open dural biopsy to distinguish the diagnosis from lymphoma. The pathological diagnosis was idiopathic HP, and DLBCL recurrence was ruled out. Following methylprednisolone pulse and oral prednisolone therapy, his neurological abnormalities gradually receded. Open dural biopsy played an important role not only in diagnosing idiopathic HP but also in relieving the pressure on the optic nerve.

Giant cell arteritis presenting with unilateral sixth nerve palsy

Giant cell arteritis (GCA) usually presents with headache, scalp tenderness and raised inflammatory markers. GCA presenting with a clinically evident cranial nerve palsy is rare and may result in a delayed or missed diagnosis if not suspected. We present the rare case of a woman in her 70s with histologically confirmed GCA presenting with a unilateral sixth nerve palsy, which responded to treatment with high-dose oral prednisolone.

Oculomotor nerve palsy as an extraintestinal manifestation of Crohn's disease

Patients with inflammatory bowel disease (IBD) may present with extraintestinal manifestations. Neurological symptoms associated with IBD are infrequent. Thus, any unexplained neurological symptom that occurs in patients with IBD should raise the suspicion of a link between the two disorders. We report a case of a man in his 60s, who was diagnosed with Crohn's disease and developed ptosis and diplopia. Neurological examination revealed oculomotor nerve palsy, sparing the pupil. MRI and magnetic resonance angiography of the brain were insignificant and no other cause was determined. He was treated with oral corticosteroids and symptoms gradually subsided. Cranial nerve palsies associated with IBD have been rarely reported. They usually involve the optic and acoustic nerve and are attributed to a common dysimmune base. This is the first reported case of oculomotor nerve palsy (III cranial nerve) associated with IBD. Clinicians treating patients with IBD should be alert for unusual neurological complications and treat them appropriately.

Neuroanaesthetic challenges in a pregnant patient with a huge cerebellopontine angle meningioma

Intracranial malignancy among pregnant women is extremely rare. Neuroanaesthesia for such high-risk patients demands extreme precautions. Our patient presented with a huge right cerebellopontine angle meningioma during the first trimester of her pregnancy. We share our valuable perianaesthetic challenges in managing her tumour-debulking surgery and a brief review of intracranial neoplasm during pregnancy.

Third cranial nerve palsy due to COVID-19 infection

We report a case of a previously healthy man in his 40s who presented with mild SARS-CoV-2 infection (COVID-19) concomitant with acute onset of left third cranial nerve palsy with restricted supraduction, adduction and infraduction. Our patient did not present any history of hypertension, hyperlipidaemia, diabetes mellitus or smoking. The patient recovered spontaneously without any antiviral treatment. To our knowledge, this is the second report of third cranial nerve palsy spontaneously resolved without any risk factors of vascular disease, specific image findings, nor any possible causes other than COVID-19. In addition, we reviewed 10 other cases of third cranial nerve palsy associated with COVID-19, which suggested that the aetiology varies greatly. As a clinician, it is important to recognise COVID-19 as a differential diagnosis for third cranial nerve palsy. Finally, we aimed to encapsulate the aetiologies and the prognosis of the third cranial nerve palsy associated with COVID-19.

Commentary and review of the literature

Vasospasm after resection of skull base tumors is a rare complication that often produces relevant ischemic sequelae. This review of the literature reports a number of published experiences that can help determine the potential causes of vasospasm after cerebello-pontine angle (CPA) tumor and -in particular-vestibular schwannoma (VS) resection, the ways to prevent it, and the methods to obtain the correct diagnosis. The cause appears to be multifactorial and the surgical approach may contribute to the pathogenesis of vasospasm. Neurosurgeons must pay attention to detect possible vasospasm at an early stage of cerebello-pontine. Cerebral blood flow measurement and transcranial Doppler are useful monitoring tools. Intra-operative prevention of vasospasm during CPA tumor resection with papaverine hydrochloride (PPV) seems to play a relevant role. In particular, PPV is a direct-acting vasodilator used to manage vasospasm during various neurosurgical operations. There is large uncertainty about intracisternal PPV dose-related efficacy and side effects. Dilution of PPV in saline prior to application is recommended to avoid complications. In our experience, in line with the literature, we use a pure PPV without excipients 60 mg/2 ml diluted in 20 cc of 0,9% saline solution (0,3%) to prevent Hearing Loss during Posterior Fossa Microvascular Decompression for Typical Trigeminal Neuralgia and other cranial nerves potentially involved during VS and other CPA tumor resection. The aim of this commentary is to analyze and discuss the role of diluted intracisternal PPV for microvascular protection of cranial nerves during CPA tumor surgery.

3D CRANI, a novel MR neurography sequence, can reliable visualise the extraforaminal cranial and occipital nerves

OBJECTIVES

We aim to validate 3D CRANI, a novel high-field STIR TSE, MR neurography sequence in the visualisation of the extraforaminal cranial and occipital nerve branches on a 3-T system. Furthermore, we wish to evaluate the role of gadolinium administration and calculate nerve benchmark values for future reference.

METHODS

Eleven consecutive patients underwent MR imaging including the 3D CRANI sequence before and immediately after intravenous gadolinium administration. Two observers rated suppression quality and nerve visualisation using Likert scales before and after contrast administration. Extraforaminal cranial and occipital nerves were assessed. Nerve calibers and signal intensities were measured at predefined anatomical landmarks, and apparent signal intensity ratios were calculated.

RESULTS

The assessed segments of the cranial and occipital nerves could be identified in most cases. The overall intrarater agreement was 79.2% and interrater agreement was 82.7% (intrarater κ = .561, p < .0001; interrater κ = .642, p < .0001). After contrast administration, this significantly improved to an intrarater agreement of 92.7% and interrater agreement of 93.6% (intrarater κ = .688, p < .0001; interrater κ = .727, p < .0001). Contrast administration improved suppression quality and significant changes in nerve caliber and signal intensity measurements. Nerve diameter and signal intensity benchmarking values were obtained.

CONCLUSION

3D CRANI is reliable for the visualization of the extraforaminal cranial and occipital nerves. Intravenous gadolinium significantly improves MR neurography when applying this sequence. Benchmarking data are published to allow future assessment of the 3D CRANI sequence in patients with pathology of the extraforaminal cranial and occipital nerves.

KEY POINTS

• MR neurography using the 3D CRANI sequence is a reliable method to evaluate the extraforaminal cranial and occipital nerves. • Gadolinium contrast administration significantly improves suppression quality and nerve visualisation. • Benchmarking values including apparent signal intensity ratios and nerve calibers depend on contrast administration and might play an important role in future studies evaluating extraforaminal cranial and occipital neuropathies.

Current advances in the surgical treatment of glossopharyngeal neuralgia

Glossopharyngeal neuralgia (GPN) is a neurological condition characterized by paroxysmal, stabbing-like pain along the distribution of the glossopharyngeal nerve that lasts from a couple of seconds to minutes. Pharmacological treatment with anticonvulsants is the first line of treatment; however, about 25% of patients remain symptomatic and require surgical intervention, which is usually done via microvascular decompression (MVD) with or without rhizotomy. More recently, the use of stereotactic radiosurgery (SRS) has been utilized as an alternative treatment method to relieve patient symptoms by causing nerve ablation. We conducted a systematic review to analyze whether MVD without rhizotomy is an equally effective treatment for GPN as MVD with the use of concurrent rhizotomy. Moreover, we sought to explore if SRS, a minimally invasive alternative surgical option, achieves comparable outcomes. We included retrospective studies and case reports in our search. We consulted PubMed and Medline, including articles from the year 2000 onwards. A total of 36 articles were included for review. Of all included patients with glossopharyngeal neuralgia, the most common offending artery compressing the glossopharyngeal nerve was the posterior inferior cerebellar artery (PICA). MVD alone was successful achieving pain relief immediately postoperatively in about 85% of patients, and also long term in 65-90% of patients. The most common complication found on MVD surgery was found to be transient hoarseness and transient dysphagia. Rhizotomy alone shows an instant pain relief in 85-100% of the patients, but rate of long-term pain relief was lower compared to MVD. The most common adverse effects observed after a rhizotomy were dysphagia and dysesthesia along the distribution of the glossopharyngeal nerve. SRS had promising results in pain reduction when using 75 Gy radiation or higher; however, long-term rates of pain relief were lower. MVD, rhizotomy, and SRS are effective methods to treat GPN as they help achieve instant pain relief and the decrease use of medication. Patients with MVD alone presented with less adverse effects than the group that underwent MVD plus rhizotomy. Although SRS may be a viable alternative treatment for GPN, further studies must be done to evaluate long-term treatment efficacy.

Cavernous sinus and jugular thromboses, base of skull osteomyelitis and cranial nerve palsies: catastrophic complications of sphenoid sinusitis

Sphenoid sinusitis is a clinically important entity as it may be associated with catastrophic complications including cavernous sinus thrombosis (CST), cerebral abscess or infarction, meningitis, base of skull osteomyelitis and cranial nerve palsies. We report a case of occult sphenoid sinusitis presenting as Streptococcus intermedius bacteraemia, bilateral jugular vein and CST, cranial nerve palsy and base of skull osteomyelitis.

Concurrent facial and trigeminal nerve palsies in a child following COVID-19 vaccination with the Pfizer vaccine

We present the case of a teenaged boy who attended our Ear, Nose and Throat Emergency clinic with a left-sided lower motor neuron (LMN) facial nerve paralysis associated with sensory loss in the distribution of the ophthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve. This happened 3 days following a first dose of the Pfizer-BioNTech BNT162b2 vaccine. He had a House-Brackmann grade V facial palsy, with marked inability to close the left eye. He was treated with a 10-day course of oral steroids and referred to ophthalmology for eye care. He had an MRI scan of the head, which revealed no space occupying lesions or other abnormalities. Over the 6-week period of follow-up, the patient's V1 and V2 sensation gradually resolved, along with improvement of his LMN facial nerve palsy to House-Brackmann grade 3. Despite the potential temporal relationship, it is not possible to establish a causal relationship between the patient's symptoms and the Pfizer-BioNTech BNT162b2 vaccine, thus further research is required.

Delayed onset peripheral facial nerve palsy after dental extraction: a case report and literature review

Peripheral facial nerve palsy (PFP) is a rare occurrence after dental extraction. Early onset PFP after the procedure can be caused by trauma and/or local anesthesia, whereas delayed onset PFP has more speculative etiologies. The latter has a certain affiliation to Bell's palsy and is therefore primordially treated with corticosteroids and long-term follow-up is often warranted. This article reports a unique case of a 30-year-old woman developing a delayed onset right-sided PFP after local intraoral anesthetic injection for molar extraction. Facial nerve injury was objectified with signs of denervation and neuritis and the patient was treated with nonsteroidal anti-inflammatory drug, corticosteroids, vitamin B supplements and mime therapy. After nine months, the patient showed an improvement of the facial muscle activity and went from a grade IV to a grade III on the House-Brackmann grading scale.

A novel case of two siblings harbouring homozygous variant in the NEUROG1 gene with autism as an additional phenotype: a case report

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.

[Midface traumatology: one focus-more than two specialist disciplines?]

Midface fractures are a common occurrence and may be associated with other injuries. It is important to perform diagnosis and treatment planning on an interdisciplinary basis. CT is the gold standard diagnostic modality. Classification according to the pattern of fracture is via the LeFort and other systems. Treatment objectives are anatomic repositioning to preserve the function of the eyes, the infraorbital nerve, and facial symmetry, as well as to preserve masticatory function. The number of surgical access routes should be minimized and incisions of the facial skin avoided wherever possible.

Surgical approach for traumatic chiasmal syndrome and complete third nerve palsy following severe head trauma

Traumatic chiasmal syndrome and traumatic third nerve palsies are rare entities usually caused by severe, high-speed, closed-head road accidents that require a thorough diagnostic work-up and complex medical and surgical management. This report presents the case of a young adult who was involved in a motorcycle accident and sustained blunt frontal head trauma, resulting in optical chiasmal syndrome and complete unilateral third nerve palsy. Ophthalmological examination demonstrated a right complete ptosis, a downward and outward position of the right eye with a fixed and dilated pupil, and bitemporal hemianopsia. In addition, funduscopy revealed bilateral optical nerve atrophy. After stabilisation and during follow-up, strabismus surgery was performed with improvement of ocular alignment in the primary position. Subsequently, eyelid surgery was carried out with good amplification of the visual field, particularly on the left side. Although challenging, surgical intervention in these cases should be considered for both functional and cosmetic reasons.

Neck pain and absence of cranial nerve symptom are clues of cervical myelopathy mimicking stroke: Two case reports

BACKGROUND

Cervical myelopathy is a potential stroke imitator, for which intravenous thrombolysis would be catastrophic.

CASE SUMMARY

We herein present two cases of cervical myelopathy. The first patient presented with acute onset of right hemiparesis and urinary incontinence, and the second patient presented with sudden-onset right leg monoplegia. The initial diagnoses for both of them were ischemic stroke. However, both of them lacked cranial nerve symptom and suffered neck pain at the beginning of onset. Their cervical spinal cord lesions were finally confirmed by cervical computed tomography. A literature review showed that neck pain and absence of cranial nerve symptom are clues of cervical myelopathy.

CONCLUSION

The current report and the review remind us to pay more attention to these two clues in suspected stroke patients, especially those within the thrombolytic time window.

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

TWIST1, a gene associated with Saethre-Chotzen syndrome, regulates extraocular muscle organization in mouse

Heterozygous loss of function mutations in TWIST1 cause Saethre-Chotzen syndrome, which is characterized by craniosynostosis, facial asymmetry, ptosis, strabismus, and distinctive ear appearance. Individuals with syndromic craniosynostosis have high rates of strabismus and ptosis, but the underlying pathology is unknown. Some individuals with syndromic craniosynostosis have been noted to have absence of individual extraocular muscles or abnormal insertions of the extraocular muscles on the globe. Using conditional knock-out alleles for Twist1 in cranial mesenchyme, we test the hypothesis that Twist1 is required for extraocular muscle organization and position, attachment to the globe, and/or innervation by the cranial nerves. We examined the extraocular muscles in conditional Twist1 knock-out animals using Twist2-cre and Pdgfrb-cre drivers. Both are expressed in cranial mesoderm and neural crest. Conditional inactivation of Twist1 using these drivers leads to disorganized extraocular muscles that cannot be reliably identified as specific muscles. Tendons do not form normally at the insertion and origin of these dysplastic muscles. Knock-out of Twist1 expression in tendon precursors, using scleraxis-cre, however, does not alter EOM organization. Furthermore, developing motor neurons, which do not express Twist1, display abnormal axonal trajectories in the orbit in the presence of dysplastic extraocular muscles. Strabismus in individuals with TWIST1 mutations may therefore be caused by abnormalities in extraocular muscle development and secondary abnormalities in innervation and tendon formation.

Cranial Nerve Anatomy

The 12 cranial nerves (CNs) all have important functions. All, except the accessory nerve, arise solely within the cranial vault. We will discuss each CN function along with its entire CN course. The modality of choice for evaluation of the CN itself is typically MRI, however, CT is very important to access the bony foramina and CN boundaries..

Monitoring surgery around the cranial nerves

Intraoperative neurophysiologic monitoring (IONM) of cranial nerve (CN) function is an essential component in multimodality monitoring of surgical procedures where CNs are at risk for injury. In most cases, IONM consists of localizing and mapping CNs and their pathways, and monitoring of CN motor function during surgery. However, CN VIII, which has no motor function, and is at risk for injury in many surgical procedures, can be easily and accurately monitored using brainstem auditory evoked potentials. For motor CNs, the literature is clear that function can be safely and adequately performed using basic electromyographic (EMG) techniques, such as recording of continuous EMG activity and electrically evoked compound muscle actions potentials. Newer techniques, such as corticobulbar motor evoked potentials and reflex studies, show good potential for a greater degree of functional assessment but require further study to determine their clinical utility. EMG remains the basic clinical neurophysiologic technique with the greatest clinical research supporting its utility in IONM of motor CN function and should be used as part of a comprehensive multimodality IONM protocol. Understanding the physiologic basis of EMG and the changes associated with altered motor function will allow the practitioner to alter surgical course to prevent injury and improve patient safety.

[Radiation therapy of malignant salivary gland tumors]

Due to their rarity, histologic heterogeneity, and localization, treatment of malignant salivary gland tumors requires an interdisciplinary approach. First-line treatment includes complete tumor resection. Postoperative radiation therapy is advised in patients with risk factors, i.e., incomplete tumor resection, high-grade tumors, or perineural invasion. Definitive radiation therapy is only advised for inoperable tumors because of significantly lower local control and survival rates when compared to combined surgery and radiation therapy. In radiation oncology, modern techniques such as intensity-modulated radiation therapy (IMRT) or particle therapy with heavy ions (i.e., C12) have led to improved outcomes in the treatment of head and neck tumors, especially of adenoid cystic carcinomas. Given the biological and physical benefits of particles, particle therapy, particularly carbon ion radiation, is a promising therapeutic approach for salivary gland tumors that will be further investigated in prospective clinical studies.

Vestibular neuronitis after COVID-19 vaccination

A woman in her 50s presented with acute vertigo and vomiting within 72 hours of receiving the Pfizer-BioNTech COVID-19 vaccine. The only neurological deficit was an impaired vestibulo-ocular reflex with horizontal nystagmus. The patient was subsequently diagnosed with vestibular neuronitis. She was managed symptomatically with prochlorperazine and betahistine, and underwent vestibular rehabilitation for 6 weeks. She made a full recovery and experienced no further symptoms. She received the second dose of the vaccine without complications.

This case demonstrates a temporal association between COVID-19 vaccination and vestibular neuronitis. Neurological adverse events are rare but recognised side effects of COVID-19 vaccines and healthcare professionals should be aware of them. This ensures timely management of patients with such presentations. Treatment should be the same as for non-vaccine-associated vestibular neuronitis. The nature of the relationship between COVID-19 vaccination and vestibular neuronitis remains unclear and patients therefore require investigations to exclude other recognised causes of vestibular neuronitis.

Enhancement of cranial nerves in Lyme neuroborreliosis: incidence and correlation with clinical symptoms and prognosis

PURPOSE

Symptoms of cranial neuritis are a common presentation of Lyme neuroborreliosis (LNB). Imaging studies are scarce and report contradictory low prevalence of enhancement compared to clinical studies of cranial neuropathy. We hypothesized that MRI enhancement of cranial nerves in LNB is underreported, and aimed to assess the prevalence and clinical impact of cranial nerve enhancement in early LNB.

METHODS

In this prospective, longitudinal cohort study, 69 patients with acute LNB were examined with MRI of the brain. Enhancement of cranial nerves III-XII was rated. MRI enhancement was correlated to clinical findings of neuropathy in the acute phase and after 6 months.

RESULTS

Thirty-nine of 69 patients (57%) had pathological cranial nerve enhancement. Facial and oculomotor nerves were most frequently affected. There was a strong correlation between enhancement in the distal internal auditory canal and parotid segments of the facial nerve and degree of facial palsy (gamma = 0.95, p < .01, and gamma = 0.93, p < .01), despite that 19/37 nerves with mild-moderate enhancement in the distal internal auditory canal segment showed no clinically evident palsy. Oculomotor and abducens nerve enhancement did not correlate with eye movement palsy (gamma = 1.00 and 0.97, p = .31 for both). Sixteen of 17 patients with oculomotor and/or abducens nerve enhancement had no evident eye movement palsy.

CONCLUSIONS

MRI cranial nerve enhancement is common in LNB patients, but it can be clinically occult. Facial and oculomotor nerves are most often affected. Enhancement of the facial nerve distal internal auditory canal and parotid segments correlate with degree of facial palsy.

Unilateral glossodynia as a harbinger of an occult cerebellopontine angle tumour

A woman in her late 80s with severe bronchomalacia was referred to a tertiary orofacial pain clinic for unexplained right unilateral glossodynia of progressive and continuous evolution for the past 8 months, spreading to the ipsilateral labiomental region, associated with ipsilateral hypoacusia. Local and general clinical examinations were unremarkable and routine blood work could not reveal any underlying systemic disease explaining the glossodynia and burning/pricking labiomental pain. Suspecting a painful trigeminal neuropathy secondary to a space-occupying lesion, a cerebral MRI was prescribed, revealing an ipsilateral cerebellopontine angle lesion, compatible with either a schwannoma or meningioma. This lesion invaded the root entry zones of cranial nerves V and VIII explaining the patient's oral pain and hypoacusia. Following a neurosurgical consultation where surgical treatment was rejected, her pain was successfully managed by topical pregabalin mouthwashes, to prevent any risk of respiratory depression related to her underlying severe bronchomalacia.

A Crafty Approach for Learning the Topographical Anatomy of the Cranial Nerves

Certain neuroanatomical relationships can be complex for students to visualise and understand. This article describes creation of a simple and cheap model to help students more easily learn the relationships of the cranial nerves to each other and to the different regions of the central nervous system (forebrain and brainstem).

Marinus of Alexandria: Galen's anatomical forefather, or: How do you solve a problem like Marinus?

Marinus of Alexandria is-with the exception of Hippocrates-the most commended ancient anatomist in the Galenic corpus, and the man to whom Galen attributes the resurgence of anatomy itself. Working in the first century C.E., he dramatically influenced the course of the history of medicine in two main ways: firstly, he made great strides in anatomical discovery, expounded in an extensive anatomical textbook that attracted much contemporary praise; secondly, he produced considerable expertise around the ancient world through teaching and didactic enterprise. Marinus generated significant renown and respect from these endeavours, which greatly benefitted future generations of medical scholars, including the infamous Galen himself, who even openly admits as such. However, despite Marinus' enormous influence on Galenic anatomy, a body of scientific knowledge that reigned supreme and untouchable for more than a millennium, he today fails to command a level of recognition befitting his epochal achievements. This article explores the factors contributing to his underrated reputation amidst incredibly mixed scholarly opinion, in contrast to the available evidence of the discoveries and innovations of a man who proved so inspirational to the most famous of ancient authors.

Acute-onset paralytic strabismus in toddlers is important to consider as a potential early sign of late-infantile Metachromatic Leukodystrophy

OBJECTIVES

Metachromatic leukodystrophy (MLD) is a fatal lysosomal storage disease characterized by progressive demyelination within the central and peripheral nervous system. Rapid diagnosis is crucial in view of evolving therapeutic options. Strabismus has anecdotally been described as a feature in children with MLD. Our first aim was to examine the prevalence of strabismus as an early or even presenting sign of MLD in two nationwide cohorts. Second, we aimed to investigate the temporal relation between the onset of strabismus and gross motor deterioration, other early onset eye movement disorders and brain white matter abnormalities.

METHODS

Clinical records of 204 MLD patients at the University Children's Hospital Tubingen and Amsterdam University Medical Center were reviewed on the presence of strabismus and other eye movement disorders. Gross motor deterioration and white matter abnormalities on brain MRI were evaluated by using the Gross Motor Function Classification in MLD and MLD LOES score, respectively.

RESULTS

We identified strabismus as an early sign in MLD patients with the late-infantile form, with a prevalence of 27% (N = 17). The onset of strabismus preceded gross motor symptoms and brain white matter abnormalities in 71% and 46% respectively of the cases. Important characteristics were an acute-onset paralytic esotropia, partly accompanied by other eye movement abnormalities, and gadolinium enhancement of the cranial nerves.

CONCLUSIONS

Acute-onset paralytic strabismus in toddlers should be considered a potential early sign of late-infantile MLD and might result from early cranial nerve involvement. Brain MRI with gadolinium contrast may facilitate early diagnosis.

Hyperintense areas in the cisternal segments of the cranial nerves: a magnetic resonance imaging study

PURPOSE

The study aimed to explore hyperintense areas in the cisternal segments of the cranial nerves using magnetic resonance imaging (MRI).

METHODS

Seventy outpatients underwent thin-sliced, coronal constructive interference steady-state (CISS) sequence and sagittal T2-weighted MRI following conventional MRI examination.

RESULTS

With the coronal CISS sequence, hyperintense areas were located in the central parts of the olfactory bulbs in 65.7% of patients. For the intracranial optic nerve and optic chiasm, hyperintense areas were detected in 98.6% of the CISS sequences and 100% of the T2-weighted images. In the optic tract, hyperintense areas were detected in 51.4% of cases. In 35% of the patients who underwent the CISS sequence, the intracranial optic nerves were considerably compressed by the internal carotid and anterior cerebral arteries, with hyperintense areas similar to those in patients without vascular compression. Hyperintense areas of the cisternal segments of the oculomotor nerve and trigeminal root were identified in 52.9% and 87.1% of the patients, respectively.

CONCLUSIONS

The hyperintense areas found within the cisternal segments of the cranial nerves delineated on the coronal CISS sequence and sagittal T2-weighted imaging may indicate the intracranial part of the glymphatic pathway through the cranial nerves. The cranial nerves may function as part of the glymphatic pathway.

Meningiomas

Meningiomas arise in various locations. Convexity tumors are relatively simple to remove. Skull base tumors and tumors adjacent to the major cerebral veins and venous sinuses can be very difficult to extirpate. Attempts at radical resection can lead to serious morbidity. The combination of bulk reduction using microsurgery followed by GKNS gives greatly improved survival and very low morbidity. With smaller tumors, GKNS may be used as the primary treatment. Increasing numbers of asymptomatic meningiomas are demonstrated either as an unexpected finding or as a residual or recurrent tumor after surgery. In all of these situations, GKNS gives a better result than observation or reoperation.