Surgical management of large lower cranial nerves schwannomas: long term results of a less aggressive resection strategy.

In an effort to reduce the high morbidity and life-threatening complications after radical resection in large schwannoma surgery, alternative strategies of nontotal resections have emerged. To evaluate the long term clinical and oncological outcome after lower cranial nerves (LCN) schwannoma surgery operated on with a cranial nerve-sparing technique. Single center retrospective cohort study of 8 consecutive patients harboring LCN schwannomas operated on between March 2005 and October 2021. The mean LCN schwannoma diameter was 33 mm (range 26-51). Seven patients (87,5%) underwent a modified retrosigmoid approach. Three patients underwent gross total resection (37,5%), 3 had received neartotal resection (mean tumor residue 0,25 cc) and subtotal resection in 2 patients who presented with an extracranial extension of the tumor (mean tumor residue 2,44 cc). Both patients had received upfront additional GKRS. The three patients who presented with preoperative CN IX & X injuries recovered within 6 months after surgery. All of the five patients freed from any preoperative CNs IX & X symptoms experienced transient (80%) or definitive (one patient) disturbances after surgery. They all improved within 6 months but one who required long term gastrostomy feeding tube. This patient harbored a schwannoma originating from the glossopharyngeal nerve, which could not be anatomically preserved during surgery. Tumor control was achieved in 100% of cases with a mean follow-up of 91 months. LCN schwannomas could be surgically removed through a less aggressive non-radical resection strategy with acceptable functional results and excellent tumor control.

Trigeminal and Glossopharyngeal Neuralgia.

Trigeminal neuralgia and glossopharyngeal neuralgia are craniofacial pain syndromes characterized by recurrent brief shock-like pains in the distributions of their respective cranial nerves. In this article, the authors aim to summarize each condition's characteristics, pathophysiology, and current pharmacotherapeutic and surgical interventions available for managing and treating these conditions.

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.

Cranial nerve involvement, visual complications and headache syndromes in Lyme disease.

PURPOSE OF REVIEW: To provide a summary of the visual manifestations and cranial neuropathies seen in Lyme disease. RECENT FINDINGS: Lyme facial palsy remains the most common manifestation of Lyme neuroborreliosis. Recent investigations show likely evidence of vagal involvement in Lyme disease. SUMMARY: The literature on Lyme neuroborreliosis continues to evolve. Lyme disease can affect nearly any cranial nerve in addition to causing various headache syndromes. The most common manifestation is Lyme disease facial palsy, occurring in up to 5-10% of patients with documented Lyme disease. Headache syndromes are common in the context of facial palsy but can occur in isolation, and more specific headache syndromes including trigeminal and geniculate neuralgias can occur rarely. Signs and symptoms indicative of vestibulocochlear nerve involvement are relatively common, although it could be that these represent other vestibular involvement rather than a specific cranial neuropathy. Optic neuritis is a controversial entity within Lyme disease and is likely overdiagnosed, but convincing cases do exist. Physicians who see any cranial neuropathy, including optic neuritis, in an endemic area can consider Lyme disease as a possible cause.

[Brain Stem and Para-Brain Stem Lesions].

Surgeries for brainstem lesions and adjacent areas needs meticulous manipulation in the profoundly deep surgical field. Moreover, it is associated with a high risk of complications pertinent to resection. The opportunity for a surgeon to amass extensive surgical experience in these lesions is limited. Additionally, the reduced tissue mobility in the brainstem, compared to other lesions, makes selecting the optimal surgical approach critical. Preoperative simulation is pivotal in surmounting these challenges. However, the limitations of preoperative simulations should be recognized in accurately depicting diminutive vessels and cranial nerves around the brainstem. Incorporating intraoperative anatomical observations and data from intraoperative monitoring into a surgical strategy is imperative. Here, we present three cases in which we believe preoperative simulation was effective; a cavernous hemangioma of the brainstem, trochlear schwannoma, and diffuse midline glioma in the pons.

Cranial Nerve Six Palsy After Vaginal Delivery with Epidural Anesthesia: A Case Report.

BACKGROUND: This case report describes a 34-year-old woman who developed diplopia and strabismus 2 weeks after a vaginal delivery and epidural anesthesia. CASE REPORT: A 34-year-old women presented to the emergency department (ED) with continued headache and new-onset diplopia after having undergone epidural anesthesia for a vaginal delivery 2 weeks prior. During that time, she underwent two blood patches, rested supine, drank additional fluids, and consumed caffeinated products for her spinal headache. When she developed double vision from a cranial nerve VI palsy, she returned to the ED. At that time, she had a third blood patch performed, and she was evaluated by a neurologist. The medical team felt the cranial nerve VI palsy was due to the downward pull of the brain and stretching of the nerve. Magnetic resonance imaging and neurosurgical closure of the dura were considered as the next steps in treatment; however, they were not performed after being declined by the patient. All symptoms were resolved over the next 3 weeks. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case illustrates the uncommon complication of a cranial nerve VI palsy from a persistent cerebrospinal fluid leak after a dural puncture. Emergency physicians must be aware that diplopia can be a rare presenting symptom after patients undergo a lumbar puncture. Furthermore, emergency physicians should be aware of the multiple treatment options available. Knowledge of the timeline of resolution of the diplopia is necessary to make shared decisions with our patients about escalating care.

Comparison of the study performance of dental students in different subfields of neuroanatomy at the Charité - Universitätsmedizin Berlin and evaluation of the neuroanatomy course in the fourth preclinical semester.

INTRODUCTION: The dentist's main working area is the head and neck region, which is innervated by the cranial nerves. On a daily basis, dentists must administer local anaesthesia to ensure pain-free treatment and differentiate between dental pain and neuropathies to avoid mistreatment. Therefore, neuroanatomical training, especially on the cranial nerves, is of immense importance for clinical practice. In order to adopt the curriculum, it is essential to constantly evaluate the quality of the training and to investigate whether there is a correlation between the students' performance and the relevance of the subfields to their work. MATERIAL AND METHODS: To address this issue, the results of MC exams in the neuroanatomy course for dental students at Charité-Universitätsmedizin Berlin from winter semester 2014/2015 to winter semester 2019/2020 were analysed. Each question was assigned to a specific subfield of neuroanatomy. We then compared cranial nerves and cranial nerve nuclei (clinically relevant) with the remaining subfields (clinically less/not relevant) to investigate whether students performed better in anatomy subfields that are more aligned with the clinical practice of a dentist. We also conducted an anonymous survey (n=201) of the dental students. RESULTS: From winter semester 2014/2015 to winter semester 2019/2020, students performed significantly (***, p< 0.001) better on the clinically relevant questions of the MC examination than on the less/not clinically relevant questions. However, when looking at each of the eleven semesters separately, only three semesters actually performed significantly better on the clinically relevant questions. Our survey also showed that students perceived the subfield of cranial nerves and cranial nerve nuclei to be the most relevant and studied it more intensively out of their own interest. DISCUSSION: The study showed that students perceived the subfield of cranial nerves and cranial nerve nuclei to be the most relevant. However, there was no direct correlation between student performance and clinically relevant questions. Using student performance alone as an indicator of relevance is not optimal, as factors such as motivation to learn can have a significant impact. CONCLUSION: Greater clinical relevance influences what students learn more intensively out of their own interest, but does not influence the results of the MC examination in favour of the subspecialty. Based on the available evidence, it is recommended that the structure of the neuroanatomy course be reconsidered.

[Developmental History of Microvascular Decompression Surgery for Cranial Nerve Dysfunction].

Trigeminal neuralgia is characterized by severe lancinating pain in the face and hemifacial spasms displayed by continuous facial muscle twitching, which may impair a patient's quality of life. Before 1960, in the United States of America, the treatment of such symptoms was only partial rhizotomy of the cranial nerves, which resulted in postoperative complications.1, 2) Afterwards, in the late 1960s, it became evident that the etiology of symptoms was an elicited arterial compression of the cranial nerves at the "Root Entry/Exit zone." Microvascular decompression(MVD)was introduced and finally became largely popularized by Gardner and Jannetta et al.3, 4) In 1978, at the Neurosurgical Meeting in New York, I incidentally witnessed slides of MVD proposed by Jannetta, which gave me a big surprise since we were then treating such patients by old-fashioned rhizotomy. Despite much ignorance displayed even in the neurosurgical meeting, I started MVD in 1980.5) In addition, in 1998 we held an Annual Meeting of the Japan Society for Microvascular Decompression Surgery, which has become more active in the fields of microsurgical techniques, diagnosis, monitoring, and long-term follow-up studies.6-8) MVD is a functional neurosurgery and satisfactory results should entail a complete and permanent cure of symptoms without any postoperative sequelae. This makes MVD a sustainable surgery.

[Microvascular Decompression for Glossopharyngeal Neuralgia].

Glossopharyngeal neuralgia is an extremely rare disease. Therefore, average neurosurgeons have limited number of opportunities for surgical experience of glossopharyngeal neuralgia. The authors mentioned several important surgical steps to achieve successful surgery. The initial cerebellar retraction should be modest to avoid unexpected rupture of bridging veins. The arachnoid between the lower cranial nerves and cerebellum should be fully dissected until the root entry/exit zones of all lower cranial nerves are easily observed. The offending arteries(especially the posterior inferior cerebellar artery)are tethered using arachnoid filaments. Complete dissection of the tethering arachnoid filaments is necessary for the offending artery to be mobilized and glued to the dural surface.

Oculomotor nerve cavernous malformation: case report and operative video.

BACKGROUND: Cavernous malformations (CMs) are clusters of thin-walled sinusoidal vessels without well-defined walls. Though they can occur anywhere in the neuroaxis, cranial nerve (CN) CMs are rare. METHOD: We report a 47-year-old male with gradual CN III palsy. Initial imaging showed no significant findings, but a follow-up MRI revealed a growing lesion along CN III. Intraoperative findings confirmed a CN III CM. Diagnosing and treating CN III CM are complex. Radiological findings lack specificity, requiring consideration of various diagnoses for patients with isolated CN III palsy and abnormal radiological findings. CONCLUSION: Surgery is the gold standard, aiming for complete lesion removal while minimizing neurological complications.

Cranial Nerve Thinning Distinguishes RFC1-Related Disorder from Other Late-Onset Ataxias.

BACKGROUND: RFC1-related disorder (RFC1/CANVAS) shares clinical features with other late-onset ataxias, such as spinocerebellar ataxias (SCA) and multiple system atrophy cerebellar type (MSA-C). Thinning of cranial nerves V (CNV) and VIII (CNVIII) has been reported in magnetic resonance imaging (MRI) scans of RFC1/CANVAS, but its specificity remains unclear. OBJECTIVES: To assess the usefulness of CNV and CNVIII thinning to differentiate RFC1/CANVAS from SCA and MSA-C. METHODS: Seventeen individuals with RFC1/CANVAS, 57 with SCA (types 2, 3 and 6), 11 with MSA-C and 15 healthy controls were enrolled. The Balanced Fast Field Echo sequence was used for assessment of cranial nerves. Images were reviewed by a neuroradiologist, who classified these nerves as atrophic or normal, and subsequently the CNV was segmented manually by an experienced neurologist. Both assessments were blinded to patient and clinical data. Non-parametric tests were used to assess between-group comparisons. RESULTS: Atrophy of CNV and CNVIII, both alone and in combination, was significantly more frequent in the RFC1/CANVAS group than in healthy controls and all other ataxia groups. Atrophy of CNV had the highest sensitivity (82%) and combined CNV and CNVIII atrophy had the best specificity (92%) for diagnosing RFC1/CANVAS. In the quantitative analyses, CNV was significantly thinner in the RFC1/CANVAS group relative to all other groups. The cutoff CNV diameter that best identified RFC1/CANVAS was ≤2.2 mm (AUC = 0.91; sensitivity 88.2%, specificity 95.6%). CONCLUSION: MRI evaluation of CNV and CNVIII using a dedicated sequence is an easy-to-use tool that helps to distinguish RFC1/CANVAS from SCA and MSA-C.

Exposure of the Cavernous Sinus via the Endoscopic Transorbital and Endoscopic Endonasal Approaches: A Comparative Study.

OBJECTIVE: To compare the endoscopic transorbital approach (ETOA) and endoscopic endonasal approach (EEA) in terms of cavernous sinus (CS) exposure. METHODS: Four cadaveric heads (8 sides) were dissected. The CS was accessed using the EEA and ETOA. Stereotactic measurements of the length of the main structures exposed, angles of attack, depths of surgical corridor, and areas of exposure were obtained and compared between the approaches. An illustrative case is also presented. RESULTS: The endoscopic transorbital approach (ETOA) exposed the lateral and superior compartments of the CS without obstruction by the internal carotid artery (ICA). The EEA exposed all compartments after mobilizing the ICA. Both approaches enabled similar exposure of the cranial nerves. The depth of surgical corridor was significantly shorter with the ETOA (P < 0.01). The areas of lateral compartment exposure were similar. As the number of instruments placed into the surgical channel increased, the available angles of attack with the ETOA became smaller and were smaller than those of the EEA. In the clinical case presented, the tumor was successfully removed without complications. CONCLUSIONS: The ETOA has the advantages of a sterile surgical channel, short operation time, little patient trauma, short surgical corridor, large exposure area, and interdural pathway; moreover, it allows dissection through the interdural space without entering the neurovascular compartment of the CS. Although the space for manipulation of instruments is limited, the ETOA is suitable for treating selected tumors in the superior and lateral compartments of the CS.

Cavernous venous malformations in and around the central nervous system. Part 2: Intradural.

Cavernous venous malformations (CavVMs) account for a spectrum of lesions with a shared pathogenesis. Their anatomical location dictates their clinical features and surgical treatment. Extradural and dura-based CavVMs were discussed in Part 1 of this review. In this part, intradural CavVMs are discussed, encompassing malformations growing within the intradural space without direct dural involvement. In addition to classic intra-axial CavVMs, cranial nerve CavVMs, intraventricular CavVMs, and intradural extramedullary spinal CavVMs are discussed in this group, given the similar natural history and specific management challenges. Herein the authors focus on critical clinical aspects of and surgical management of these malformations based on their location and discuss optimal surgical approaches at each of these anatomical locations with illustrative cases. The commonalities of the natural history and surgical management that are dictated by anatomical considerations lend to a new location-based taxonomy for classification of CavVMs.

Extra-axial cranial nerve enhancement: a pattern-based approach.

Cranial nerve enhancement is a common and challenging MRI finding that requires a meticulous and systematic evaluation to identify the correct diagnosis. Literature mainly describes the various pathologies with the associated clinic-radiological characteristics, while the radiologist often needs a reverse approach that starts from the radiological findings to reach the diagnosis. Therefore, our aim is to provide a new and practical pattern-based approach to cranial nerve enhancement, which starts from the radiological findings and follows pattern-driven pipelines to navigate through multiple differential diagnoses, guiding the radiologist to reach the proper diagnosis. Firstly, we reviewed the literature and identified four patterns to categorize the main pathologies presenting with cranial nerve enhancement: unilateral linear pattern, bilateral linear pattern, unilateral thickened pattern, and bilateral thickened pattern. For each pattern, we describe the underlying pathogenic origin, and the main radiological features are displayed through high-quality MRI images and illustrative panels. A suggested MRI protocol for studying cranial nerve enhancement is also provided. In conclusion, our approach for cranial nerve enhancement aims to be an easy tool immediately applicable to clinical practice for converting challenging findings into specific pathological patterns.

Spinal procedures, pneumocephalus, and cranial nerve palsies: A review of the literature.

Purpose: Minimally invasive and surgical spine procedures are commonplace with various risks and complications. Cranial nerve palsies, however, are infrequently encountered, particularly after procedures such as lumbar punctures, epidural anesthesia, or intrathecal injections, and are understandably worrisome for clinicians and patients as they may be interpreted as secondary to a sinister etiology. However, a less commonly considered source is a pneumocephalus which may, in rare cases, abut cranial nerves and cause a palsy as a benign and often self-resolving complication. Here, we present the case of a patient who underwent an intrathecal methotrexate infusion for newly diagnosed non-Hodgkin's T-cell lymphoma and subsequently developed an abducens nerve palsy due to pneumocephalus. We highlight the utility of various imaging modalities, treatment options, and review current literature on spinal procedures resulting in cranial nerve palsies attributable to pneumocephalus presenting as malignant etiologies.

A comprehensive study on the arterial vasculature of the brain in water buffalo (Bubalus bubalis): Clinical correlates.

The present study was designed to provide a comprehensive analysis of the anatomical aspects of arterial blood vasculature in the water buffalo brains. Fifty cranial cavities of adult water buffaloes were opened via both the dorsal and ventral approaches and the arteries were exposed and photographed. The buffalo rostral epidural rete mirabile generally resembled that of large ruminants. The oculomotor, abducent and trigeminal nerves were intimately associated with the rostral rete. Similar to the majority of ruminants, the arterial circle of the brain was heart-shaped in buffalos and presented all collateral blood vessels as mentioned in the previous literature. The study further revealed that the cranial nerve roots were closely related to the arterial circle of the brain and could be used as indicators for differentiating various branches of the arterial circle of the brain. In addition to the usual variations of the arterial circle of the brain, a bihemispheric rostral cerebral artery along with an aplastic rostral cerebral artery were reported for the first time. The deviant behaviour of the rostral cerebral artery forms a baseline to study various clinical conditions of the blood vasculature in the buffalo brain. The rostral choroidal, middle cerebral and the caudal cerebral arteries constantly were emerged as single vessels without any variations. In conclusion, the anatomy of the arterial vasculature of the buffalo brain observed in the present study provided evidence of its morphological resemblance to other species of the Bovini tribe.

Tendon-Sparing Extraocular Muscle Enlargement Associated With Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an inflammatory, sensorimotor polyneuropathy. It has presented with a variety of orbital and neuro-ophthalmic manifestations, including cranial nerve hypertrophy and a single case of extraocular muscle enlargement. The authors present a second case of tendon-sparing, extraocular muscle enlargement, resulting in new-onset diplopia and strabismus in a teenager with CIDP. The workup ruled out alternative causes of extraocular muscle enlargement, such as hyperthyroidism, inflammation, or malignancy. As with other cases of CIDP, management involved a combination of immunoglobulin therapy and anti-inflammatory medications. The patient experienced resolution of his symptoms, and radiologic improvement was noted in the muscle enlargement. As many CIDP patients have a favorable treatment response and long-term prognosis, awareness of this rare disease with an early and accurate diagnosis is important.

Traumatic cavernous sinus syndrome - A peculiar presentation of multiple cranial nerve neuropathies following a minor head injury: Case report and literature review.

BACKGROUND: In patients with traumatic head injuries, the percentage of cranial nerve injuries (CNI) range from4.3 to 17.6% in which majority are isolated CNI[1-5].In present literature, moderate to severe types of head injuries are often studied which may result in a lack of representation and description of CNI associated with minor head injuries (MHI). Alongside this peculiar case of a traumatic cavernous sinus syndrome (CSS) that is non-thrombotic and non-fistulous in nature, this paper aims to analyse traumatic CNI in non-severe head injuries and the surrounding literature. CASE REPORT: A 65-year-old man who had sustained a minor head injury was found to have CNI of III, IV and VI.Brain imaging showed scattered traumatic subarachnoid haemorrhage and a non-displaced right zygomatic arch fracture. Despite the short course of high dose dexamethasone, he showed only partial recovery of his CNI after one year. CONCLUSION: We present a case of traumatic CSS likely secondary to tractional injury from a MHI. Injury to the extraocular nerves wasfound to be one of the more commonly observed combination of CNI from the literature review conducted. In patients with MHI, multiple CNI is less common. Hence, consideration should be given to work upfor secondary causes such as tumours. There is presently no known clear identifiable pattern of CNI associated with MHI. CT brain findings of skull base fractures and early onset of cranial nerve palsies are generally associated with worse outcomes. More remains to be studied about tractional CNI in non-severe head injuries.

The value of 3D high-resolution IR-prepared fast spoiled gradient-recalled MRI in the diagnosis of meningeal carcinomatosis involving the cranial nerves.

PURPOSE: The purpose of this study was to investigate the clinical utility of three-dimension (3D) high-resolution inversion recovery (IR)-prepared fast spoiled gradient-recalled (SPGR) magnetic resonance imaging (MRI) in the diagnosis of cranial nerve meningeal carcinomatosis (MC). METHODS: A total of 114 patients with MC from January 2015 to March 2020 were enrolled and their MRIs were analyzed retrospectively. All patients underwent MRIs before being administered a contrast agent. Both a 2D conventional MRI sequence and a 3D IR-prepared fast SPGR high-resolution T1-weighted (BRAVO) scan sequence were measured after contrast agent administration. The characteristics of MC and the involved cranial nerves were then examined. RESULTS: Among the 114 MC patients, 81 (71.05%) had cranial nerve enhancement on contrast-enhanced 3D-BRAVO imaging, while only 41 (35.96%) had image enhancement on conventional MRI. The contrast-enhanced 3D-BRAVO displayed stronger image contrast enhancement of the cranial nerves than the conventional MRI (P < 0.001). Furthermore, detection rates for the facial and auditory nerves, trigeminal nerve, oculomotor nerve, sublingual nerve, optic nerve, glossopharyngeal/vagal/accessory nerve, and abductor nerve on contrast-enhanced 3D-BRAVO imaging were 58.77%, 47.37%, 9.65%, 8.77%, 5.26%, 3.51%, and 0.88%, respectively. We found a statistically significant difference between the affected facial and auditory nerves, as well as the trigeminal nerve, oculomotor nerve, sublingual nerve, and optic nerve. CONCLUSION: In MC, contrast-enhanced 3D-BRAVO imaging displayed the cranial nerves more effectively than 2D conventional enhanced MRI. The facial, auditory, and trigeminal nerves are the primary nerves involved in MC, and improved scanning of these nerves would aid in the early detection and treatment of MC.