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.

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.

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review

BACKGROUND AND OBJECTIVES

Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse.

METHODS

A single-institution cohort study and systematic literature review of LCNS were performed.

RESULTS

Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients.

CONCLUSION

Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control-particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

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.

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.

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.

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.

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.

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.

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.

[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.

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.

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.

The Significance of Bell's Palsy That Presents as Monocranial Versus Polycranial Neuropathy: A Case Series and Systematic Literature Review

PURPOSE

To investigate the effect of Bell's palsy (BP) presenting as polycranial neuropathy (PCN) compared with BP caused by isolated facial nerve (CNVII).

METHODS

We carried out a retrospective cohort study of the medical records of all consecutive patients who were diagnosed with BP at a single tertiary referral center between 2010 and 2017. Included were patients 18 years or older who were clinically diagnosed with BP and completed 7 days of systemic steroidal treatment and at least 6 months of follow-up. The patients were divided into two groups according to whether the BP derived from a monocranial neuropathy or a PCN. Demographics and BP severity and outcome were compared between these groups. A systematic literature review using Medline via "PubMed," "Embase," and "Web of Science" was conducted.

RESULTS

In total, 321 patients with BP were enrolled. The median (interquartile range) age at presentation was 44 (33-60) years. Sex distribution showed male predominance of 57.6% (n = 185) versus 42.4% (n = 136), and 21.2% (n = 68) had PCN. The most concomitantly affected cranial nerve (CN) was the trigeminal (CNV; n = 32, 47%), followed by the glossopharyngeal nerve (CNIX; n = 14, 21%) and the audiovestibular nerve (CNVIII; n = 10, 15%). Age, House-Brackmann score on presentation, and diabetes mellitus (DM) were independent predictors for PCN etiology ( p = 0.001, p = 0.034, and p < 0.001, respectively). Each increase in 1 year of age was associated with additional odds ratio (95% confidence interval) of 0.97 (0.95-0.99) for PCN. The odds ratio (95% confidence interval) associated with DM was 8.19 (4.02-16.70). Our systematic literature review identified 1,440 patients with the PCN type of BP. The most commonly affected CN was the trigeminus (25-48%), followed by the glossopharyngeal and audiovestibular nerves (2-19% and 0-43%, respectively).

CONCLUSION

The severity of facial weakness on initial presentation among PCN patients was significantly higher compared with the monocranial neuropathy-type BP patients. The authors believe that the significant association and prevalence rate ratio between DM and PCN warrant that a patient presenting with PCN undergo screening for DM.

Comparing 1.5 T and 3.0 T MR data for 3D visualization of neurovascular relationships in the posterior fossa

BACKGROUND

Neurovascular relationships in the posterior fossa are more frequently investigated due to the increasing availability of 3.0 Tesla MRI. For an assessment with 3D visualization, no systematic analyzes are available so far and the question arises as to whether 3.0 Tesla MRI should be given preference over 1.5 Tesla MRI.

METHODS

In a prospective study, a series of 25 patients each underwent MRI investigations with 3D-CISS and 3D-TOF at 1.5 and 3.0 Tesla. For both field strengths separately, blood vessel information from the TOF data was fused into the CISS data after segmentation and registration. Four visualizations were created for each field strength, with and without optimization before and after fusion, which were evaluated with a rating system and verified with the intraoperative situation.

RESULTS

When only CISS data was used, nerves and vessels were better visualized at 1.5 Tesla. After fusion, flow and pulsation artifacts were reduced in both cases, missing vessel sections were supplemented at 3.0 Tesla and 3D visualization at 1.5 and 3.0 Tesla led to anatomically comparable results. By subsequent manual correction, the remaining artifacts were further eliminated, with the 3D visualization being significantly better at 3.0 Tesla, since the higher field strength led to sharper contours of small vessel and nerve structures.

CONCLUSION

3D visualizations at 1.5 Tesla are sufficiently detailed for planning microvascular decompression and can be used without restriction. Fusion further improves the quality of 3D visualization at 3.0 Tesla and enables an even more accurate delineation of cranial nerves and vessels.

Transmastoid/Infralabyrinthine Approach to the Jugular Foramen: 2-Dimensional Operative Video

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE

This approach is intended for tumors centered in the jugular foramen with extensions between intracranial and extracranial spaces, possible spread to the middle ear, and variable bony destruction. 1,2.

ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT

Jugular foramen paragangliomas are complex lesions that usually invade and fill related venous structures. They present complex relationships with skull base neurovascular structures as internal carotid artery, lower cranial nerves (CNs), middle ear, and mastoid segment of facial nerve. In this way, it is essential to perform an adequate preoperative vascular study to evaluate sinus patency and the tumor blood supply, besides a computed tomography scan to depict bone erosion.

ESSENTIAL STEPS OF THE PROCEDURE

Mastoidectomy through an infralabyrinthine route up to open the lateral border of jugular foramen, allowing exposure from the sigmoid sinus to internal jugular vein. Skeletonization of facial canal without exposure of facial nerve is performed and opening of facial recess to give access to the middle ear in way of a fallopian bridge technique. 2-10.

PITFALLS/AVOIDANCE OF COMPLICATIONS

If there is preoperative preservation of lower CN function, it is important to not remove the anteromedial wall of the internal jugular vein and jugular bulb. In addition, facial nerve should be exposed just in case of preoperative facial palsy to decompress or reconstruct the nerve.

VARIANTS AND INDICATIONS FOR THEIR USE

Variations are related mainly with temporal bone drilling depending on the extensions of the lesion, its source of blood supply, and preoperative preservation of CN function.Informed consent was obtained from the patient for the procedure and publication of his image.Anatomy images were used with permission from:• Ceccato GHW, Candido DNC, and Borba LAB. Infratemporal fossa approach to the jugular foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.• Ceccato GHW, Candido DNC, de Oliveira JG, and Borba LAB. Microsurgical Anatomy of the Jugular Foramen. In: Borba LAB and de Oliveira JG. Microsurgical and Endoscopic Approaches to the Skull Base. Thieme Medical Publishers. 2021.

Microscopic with Endoscopic Surgery via Subtemporal Approach for Cavernous Sinus Cholesteatomas

OBJECTIVE

The aim of this study was to retrospectively analyze the clinical data of 16 patients with cavernous sinus cholesteatomas, explore the surgical outcomes, and summarize the surgical experience.

METHODS

Patients with cavernous sinus cholesteatomas underwent surgery between June 2016 and June 2022 at the Department of Neurosurgery at the First Affiliated Hospital of Soochow University. Clinical data were obtained from all patients for analysis.

RESULTS

Common preoperative symptoms included headache, dizziness, diplopia, ptosis, and facial numbness. There were 7 patients with 2 or more symptoms. There were 13 patients with total resection and 3 patients with subtotal resection. There were 5 patients with improved postoperative symptoms, 10 patients with no significant change, and 1 patient with worse symptoms. New postoperative cranial nerve defects occurred in 4 patients. During the follow-up, all patients had favorable prognosis without progression.

CONCLUSIONS

Using "double-scope" technique, the subtemporal approach, a surgical strategy for cavernous sinus cholesteatomas, was sufficient to completely resect the tumors.

Intrinsic epidermoid cyst of the brainstem in children-review and case report

PURPOSE

The study aimed to summarize all published cases of intrinsic brainstem epidermoid cysts in a timeline to highlight the specific characteristics and individualize the disease, in addition to discussing the best treatment used.

METHODS

The scientific literature on pediatric cases of intrinsic epidermoid cysts of the brainstem was analyzed. We present the case of a 1.5-year-old male with incidental presentation, who was treated with gross total resection. We summarize all previously published cases to individualize the disease.

RESULTS

We identified 21 patients, including 10 boys and 11 girls, with a mean age of 4.85 (1-15) years at the time of surgery. The most frequent symptoms were cranial nerve palsy (71.4%), pyramidal tract deficit (57.14%), and headache (52.38%). Among the affected cranial nerves, VII was the most frequently reported in 10 patients.

CONCLUSION

Brainstem epidermoid cysts are extremely rare pathologies with relevant age involvement in young children. The treatment objective should be the maximum resection of the lesion through a careful approach and with the appropriate tools for the functional preservation of the patient.

The Natural History of Observed SDHx -Related Head and Neck Paragangliomas Using Three-Dimensional Volumetric Tumor Analysis

OBJECTIVE

Characterize the natural history and clinical behavior of head and neck paragangliomas (HNPGLs) in subjects with succinate dehydrogenase ( SDHx ) pathogenic variants using volumetric tumor measurements.

STUDY DESIGN

Cohort study.

SETTING

Tertiary academic referral center.

PATIENTS

Subjects with SDHx HNPGLs under observation for at least 6 months with 2 or more magnetic resonance imaging or computed tomography scans.

INTERVENTIONS

Diagnostic interventions include next-generation sequencing, magnetic resonance imaging, and computed tomography. Therapeutic interventions include microsurgical resection or stereotactic radiosurgery.

MAIN OUTCOME MEASURES

Radiographic progression was defined as a 20% or greater increase in volume. Cranial nerve (CN) functional outcomes were assessed using clinical documentation.

RESULTS

A total of 19 subjects with 32 tumors met the inclusion criteria. Median radiographic follow-up was 2.2 years, and the median volumetric growth rate was 0.47 cm 3 /yr. Kaplan-Meier estimated rates of survival free of radiographic progression for all SDHx tumors at 1, 2, and 3 years were 69, 50, and 22%, respectively. No tumors developed new CN palsies during the period of observation.

CONCLUSIONS

Over intermediate-term follow-up, observation of treatment-naive SDHx -related HNPGLs did not result in new cranial neuropathy. Although indefinite observation is only appropriate for select cases, these data support an interval of observation to characterize growth rate in asymptomatic to minimally symptomatic patients, who are at high risk of treatment-related morbidity. Given the early age at diagnosis and high risk of bilateral multifocal phenotypes in SDHx HNPGL mutation carriers, these data may aid in optimizing patient tumor control and CN functional preservation. Further studies are necessary to determine whether pretreatment growth rate is correlated with clinical outcomes.

Trigeminal hybrid nerve sheath tumor - a case report and literature review

BACKGROUND

Hybrid nerve sheath tumors (HNST) contain elements of more than one established sub-type of nerve sheath tumor and have been recently recognized in the 2016 WHO classification of central nervous system tumors. While common in the peripheral nerves and extracranial branches of cranial nerves, only one case has been previously documented of an intracranial HNST arising from a cranial nerve.

CASE DESCRIPTION

We describe a large, multi-compartmental intracranial hybrid nerve sheath tumor arising from the trigeminal nerve in a 22-year-old lady who presented with clinical and radiological features suggestive of a right cerebellopontine angle mass. Histopathological examination following retrosigmoid excision of the tumor revealed histological and immunohistochemical features of a schwannoma and a perineurioma.

CONCLUSIONS

HNSTs are likely to be underreported in the intracranial region. The clinical course of these tumors and the reason for their occurrence in this location are not known.

Long-term functional outcomes and complications of microsurgical resection of brainstem cavernous malformations: a systematic review and meta-analysis

Brainstem cavernous malformations (CMs) encompass up to 20% of all intracranial CMs and are considered more aggressive than cerebral CMs because of their high annual bleeding rates. Microsurgical resection remains the primary treatment modality for CMs, but long-term functional outcomes and complications are heterogenous in the literature. The authors performed a systematic review on brainstem CMs in 4 databases: PubMed, EMBASE, Cochrane library, and Google Scholar. We included studies that reported on the long-term functional outcomes and complications of brainstem CMs microsurgical resection. A meta-analysis was performed and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The search yielded 4781 results, of which 19 studies met our inclusion criteria. Microsurgery was performed on 940 patients (mean age 35 years, 46.9% females). Most of the brainstem CMs were located in the pons (n = 475). The pooled proportions of improved, stable, and worsened functional outcomes after microsurgical resection of brainstem CMs were 56.7% (95% CI 48.4-64.6), 28.6% (95% CI 22.4-35.7), and 12.6% (95% CI 9.6-16.2), respectively. CMs located in the medulla were significantly (p = 0.003) associated with a higher proportion of improved outcome compared with those in the pons and midbrain. Complete resection was achieved in 93.3% (95% CI 89.8-95.7). The immediate postoperative complication rate was 37.2% (95% CI 29.3-45.9), with new-onset cranial nerve deficit being the most common complication. The permanent morbidity rate was 17.3% (95% CI 10.5-27.1), with a low mortality rate of 1% from the compiled study population during a mean follow-up of 58 months. Our analysis indicates that microsurgical resection of brainstem CMs can result in favorable long-term functional outcomes with transient complications in the majority of patients. Complete microsurgical resection of the CM is associated with a lower incidence of CM hemorrhage and the morbidity related to it.

Minimally invasive extraocular cranial nerve electromyography

OBJECTIVE

A reluctance to monitor extraocular cranial nerve (EOCN) function has restricted skull base surgery worldwide. Spontaneous and triggered electromyography (EMG) monitoring can be recorded intraoperatively to identify and assess potential cranial nerve injury. Determining the conductive function of EOCNs requires the collection of clear, reliable, and repeatable compound muscle action potentials (CMAPs) secondary to stimulation. EOCN EMG needle electrodes can, although infrequently, cause ocular morbidity including hematoma, edema, and scleral laceration. The aim of this study was to ascertain if minimally invasive 7-mm superficial needle electrodes would record CMAPs as well as standard 13-mm intraorbital electrodes.

METHODS

Conventionally, the authors have monitored EOCN function with intraorbital placement of paired 13-mm needle electrodes into three extraocular muscles: medial rectus, superior oblique, and lateral rectus. A prospective case-control study was performed using shorter (7-mm) needle electrodes. A single minimally invasive electrode was placed superficially near each extraocular muscle and coupled with a common reference. CMAPs were recorded from the minimally invasive electrodes and compared with CMAPs recorded from the paired intraorbital electrodes. The presence or absence of CMAPs was analyzed and compared among EMG recording techniques.

RESULTS

A total of 429 CMAPs were analyzed from 71 EOCNs in 25 patients. The experimental setup yielded 167 true-positive (39%), 106 false-positive (25%), 17 false-negative (4%), and 139 true-negative (32%) responses. These values were used to calculate the sensitivity (91%), specificity (57%), positive predictive value (61%), and negative predictive value (89%). EOCN electrodes were placed in 82 total eyes in 58 patients (CMAPs were obtained in 25 patients). Twenty-six eyes showed some degree of edema, bruising, or bleeding, which was transient and self-resolving. Three eyes in different patients had complications from needle placement or extraction including conjunctival hemorrhage, periorbital ecchymosis, and corneal abrasion, ptosis, and upper eyelid edema.

CONCLUSIONS

Because of artifact contamination, 106 false-positive responses (25%), and 17 false-negative responses (4%), the minimally invasive EMG technique cannot reliably record CMAP responses intraoperatively as well as the intraorbital technique. Less-invasive techniques can lead to an inaccurate EOCN assessment and potential postoperative morbidity. EOCN palsies can be debilitating and lifelong; therefore, the benefits of preserving EOCN function outweigh the potential risks of morbidity from electrode placement. EMG monitoring with intraorbital electrodes remains the most reliable method of intraoperative EOCN assessment.

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.

Unclassified clinical presentations of chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

To assess the ability of the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) clinical criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) to include within their classification the whole spectrum of clinical heterogeneity of the disease and to define the clinical characteristics of the unclassifiable clinical forms.

METHODS

The 2021 EAN/PNS clinical criteria for CIDP were applied to 329 patients fulfilling the electrodiagnostic (and in some cases also the supportive) criteria for the diagnosis of CIDP. Clinical characteristics were reviewed for each patient not strictly fulfilling the clinical criteria ('unclassifiable').

RESULTS

At study inclusion, 124 (37.5%) patients had an unclassifiable clinical presentation, including 110 (89%) with a typical CIDP-like clinical phenotype in whom some segments of the four limbs were unaffected by weakness ('incomplete typical CIDP'), 10 (8%) with a mild distal, symmetric, sensory or sensorimotor polyneuropathy confined to the lower limbs with cranial nerve involvement ('cranial nerve predominant CIDP') and 4 (1%) with a symmetric sensorimotor polyneuropathy limited to the proximal and distal areas of the lower limbs ('paraparetic CIDP'). Eighty-one (65%) patients maintained an unclassifiable presentation during the entire disease follow-up while 13 patients progressed to typical CIDP. Patients with the unclassifiable clinical forms compared with patients with typical CIDP had a milder form of CIDP, while there was no difference in the distribution patterns of demyelination.

CONCLUSIONS

A proportion of patients with CIDP do not strictly fulfil the 2021 EAN/PNS clinical criteria for diagnosis. These unclassifiable clinical phenotypes may pose diagnostic challenges and thus deserve more attention in clinical practice and research.

Proton beam radiation therapy for vestibular schwannomas-tumor control and hearing preservation rates: a systematic review and meta-analysis

OBJECTIVE

Proton beam therapy is considered, by some authors, as having the advantage of delivering dose distributions more conformal to target compared with stereotactic radiosurgery (SRS). Here, we performed a systematic review and meta-analysis of proton beam for VSs, evaluating tumor control and cranial nerve preservation rates, particularly with regard to facial and hearing preservation.

METHODS

We reviewed, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) articles published between 1968 and September 30, 2022. We retained 8 studies reporting 587 patients.

RESULTS

Overall rate of tumor control (both stability and decrease in volume) was 95.4% (range 93.5-97.2%, p heterogeneity= 0.77, p<0.001). Overall rate of tumor progression was 4.6% (range 2.8-6.5%, p heterogeneity < 0.77, p<0.001). Overall rate of trigeminal nerve preservation (absence of numbness) was 95.6% (range 93.5-97.7%, I2 = 11.44%, p heterogeneity= 0.34, p<0.001). Overall rate of facial nerve preservation was 93.7% (range 89.6-97.7%, I2 = 76.27%, p heterogeneity<0.001, p<0.001). Overall rate of hearing preservation was 40.6% (range 29.4-51.8%, I2 = 43.36%, p heterogeneity= 0.1, p<0.001).

CONCLUSION

Proton beam therapy for VSs achieves high tumor control rates, as high as 95.4%. Facial rate preservation overall rates are 93%, which is lower compared to the most SRS series. Compared with most currently reported SRS techniques, proton beam radiation therapy for VSs does not offer an advantage for facial and hearing preservation compared to most of the currently reported SRS series.

Utility of Dual Monitoring of the Lower Cranial Nerve Motor-Evoked Potentials Threshold Level Criterion to Predict Swallowing Function in Skull Base and Brainstem Surgery

PURPOSE

Evaluate the value of bilateral final/baseline threshold level changes of lower cranial nerve MEPs in postoperative swallowing function deterioration prediction.

METHODS

Bilateral lower cranial nerve motor-evoked potentials (MEPs) were recorded in 51 patients who underwent treatment for skull base and brainstem tumors. Corkscrew-like electrodes were positione 2 cm below C3/C4 and Cz. The MEPs were recorded from different muscle groups, including the posterior pharyngeal wall muscle, tongue muscle, genioglossus muscle, and cricothyroid muscle through paired needle electrodes. Swallowing function was assessed clinically using the Mann Assessment of Swallowing Ability score before and after the procedure at 7 days, 1 month, and 3 months.

RESULTS

Bilateral final/baseline threshold level increases in lower cranial nerve MEPs under the dual monitoring were significantly correlated with postoperative swallowing function deterioration ( r = 0.660 at 7 days, r = 0.735 at 1 month, and r = 0.717 at 3 months; p < 0.05). Bilateral final/baseline threshold level changes of more than 20% were recorded in 23 of the 51 patients, with 21 patients experiencing swallowing function deterioration postoperatively. The other 28 patients had bilateral threshold level changes of less than 20%, with 26 patients maintaining or improving their swallowing function, and 12 of those patients presented transient deterioration of swallowing function in the early postoperative period.

CONCLUSIONS

Dual monitoring of lower cranial nerves and their different muscle groups MEPs was a safe and effective way to predict postoperative swallowing function. An increase in bilateral final/baseline threshold level change of more than 20% was predictive of permanent swallowing deterioration, especially in patients with poor swallowing function preoperatively.

[Isolated IgG4 hypertrophic pachymeningitis with cranial nerve involvement]

IgG4-related (IgG4-RD) disease is a relatively newly identified, chronic autoimmune disorder that can affect any organ system. The disease is relatively rare. It has mostly systemic presentation, however it can also appear in isolated form in one single organ. In our report, we demonstrate an elderly male patient’s case with IgG4-RD presented in the form of diffuse meningeal inflammation and hypertrophic pachymeningitis with one-sided cranial nerve and intraventricular involvement.

CLINICAL-AND-FUNCTIONAL ASSESSMENT OF THE EARLY POSTOPERATIVE OUTCOME OF SURGICAL TREATMENT OF PATIENTS WITH VESTIBULAR SCHWANNOMA

The incidence of vestibular schwannoma (VS) increased largely within the last 50 years from 1,5 cases per 100 thousand persons to 4,2 (for the last decade). The approaches to the management of VS patients vary significantly in different medical centers and different countries. The search for the consensus in selecting strategy of VS treatment based on systemic clinical-and-functional assessment of treatment outcome is topical nowadays. The aim of study - to analyze the clinical-and-functional early postoperative outcome of the surgical treatment of vestibular schwannoma depending on the stage of the disease. The findings of the examination and the outcomes of the surgical treatment of 27 VS patients were retrospectively analyzed. The patients were treated at the Department of Subtentorial Neurosurgery of the State Institution "Romodanov Institute of Neurosurgery of the NAMS of Ukraine" in 2018-2019. According to Koos classification, three groups of the patients were delineated for the analysis of the results of the study, namely, group 1 (Koos II) - 8 (29,6 %) patients; group 2 (Koos III) - 6 (22,2 %); and group 3 (Koos IV) - 13 (48,2 %). The complex clinical examination, in particular clinical-and-instrumental otoneurological examination and the evaluation of the neurological status according to the Scale for the assessment of the functional treatment outcome were performed preoperatively and early postoperatively. The data were statistically processed. In the patients with small tumors (group 1, Koos II), the socially useful hearing on the affected side was preserved preoperatively necessitating the caution for selecting the treatment strategy in these patients. When pre- and postoperative clinical symptoms were compared in group 1, the statistically significant worsening of the hearing to the socially non-useful, the unilateral subjective tinnitus, the dysfunction of the facial nerve, the decreased sense of taste/loss of taste on the anterior 2/3 of the tongue on the affected side were found. Upon the surgical treatment, the rate of the neurological deficit increased, and the severity grade of the neurological deficit increased by about 10 points. The overall preoperative score in group 3 (Koos IV) was significantly different from that in other groups. The progression of the disease to the stage of Koos IV results in the neurological deficit that is equivalent by the set of the neurological symptoms and their severity to that in early postoperative period in patients with Koos III. In group 3, the rate of the dysfunction of the facial nerve and the caudal group of the cranial nerves increased postoperatively with concomitant decreased sense of taste/loss of taste on the anterior 2/3 of the tongue on the affected side and statocoordinatory impairments. The overall preoperative score differed significantly between all groups. In group 3, the postoperative overall score did not differ from preoperative one, although the postoperative overall score in group 3 (Koos ІV) differed significantly from that in other two groups. The proposed scale for the assessment of the functional outcome of the VS treatment is versatile and represents the integral element of the systemic assessment of the clinical-and-functional status of VS patient. There are good reasons to integrate proposed scale into the general scheme of the medical care for VS patients allowing for the objective assessment of the otoneurological patterns in the patients in the dynamics of the treatment. The analysis of our own findings and the literature data proved the relevance of the problem requiring further task-oriented scientific inquiry. The important aspects of the problem relate to the optimization and improvement of the diagnostic and treatment strategy according to the principles of individualization and multimodality allowing for increasing the level of consensus and improving the functional outcome of the treatment.

Part III: Arachnoid Membranes, Cranial Nerves, and Surgical Implications

BACKGROUND Anatomical dissections play an irreplaceable role in the training of new generations of effective neurosurgeons, especially when addressing skull base lesions is required.The Authors describe an inter-laboratory dissection study aimed at improving the knowledge of a complex region of the skull base. The anterior and middle incisural spaces are of remarkable anatomical and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purposes of this study are to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.METHODS Thirteen anatomical specimens, including five injected specimens, were dissected in this study. In the formalin-fixed specimens, vessels were injected with colored silicone.RESULTS The anatomical study focused on the description of the relationships between bony dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.CONCLUSIONS Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases. The high-definition pictures reported in this study could represent useful support to understand the anatomy of this complex region.Finally, our study could provide guidance to neurosurgical centers in which resources are limited that are either planning to establish their own cadaver dissection laboratory or failed to do so because of the supposed high-costs.

A Case of Intratemporal Rhabdomyosarcoma in a Child Presenting with VIIth, IXth, and Xth Cranial Nerve Paralysis

OBJECTIVE

Rhabdomyosarcoma is the most common soft tissue tumor in children, with average age of onset being 5 years, and approximately 70% cases diagnosed below 10 years of age. It accounts for 37% of primary head and neck malignancies in children. Chemotherapy with surgery, and radiation is selected as the primary treatment. We report a rare case of rhabdomyosarcoma in the temporal bone presenting with glossopharyngeal and vagus nerve paralysis as well as facial palsy.

CASE REPORT

The patient was a 6-year-old boy, and his initial symptom was dizziness followed by facial palsy and hoarseness. Although a severe type of otitis media was suspected in the first clinic, CT and MRI showed a temporal bone tumor with parameningeal extension. Biopsy with cortical mastoidectomy revealed an embryonal-type rhabdomyosarcoma. Pretreatment re-excision was abandoned because of parameningeal involvement. The tumor disappeared after a series of chemotherapy, however, meningeal dissemination occurred, and he eventually died even after an additional administration of anti-cancer agents and intensive modulated radiation therapy.

CONCLUSION

In the case of facial palsy concomitant with other cranial nerve paralysis, care must be taken into neoplastic origin. Early image diagnosis may offer a chance of complete resection in addition to chemoradiotherapy.

Feasibility of Upper Cranial Nerve Sonication in Human Application via Neuronavigated Single-Element Pulsed Focused Ultrasound

Sonicating deep brain regions with pulsed focused ultrasound using magnetic resonance imaging-guided neuronavigation single-element piezoelectric transducers is a new area of exploration for neuromodulation. Upper cranial nerves such as the trigeminal nerve and other nerves responsible for sensory/motor functions in the head may be potential targets for ultrasound pain therapy. The location of upper cranial nerves close to the skull base poses additional challenges when compared with conventional cortical or middle brain targets. In the work described here, a series of computational and empirical testing methods using human skull specimens were conducted to assess the feasibility of sonicating the trigeminal pathway near the sphenoid bone region. The results indicate a transducer with a focal length of 120 mm and diameter of 85 mm (350 kHz) can deliver sonication to upper cranial nerve regions with spatial accuracy comparable to that of focused ultrasound brain targets used in previous human studies. Temperature measurements in cortical bone and in the skull base with embedded thermocouples yield evidence of minimal bone heating. Conventional pulse parameters were found to cause reverberation interference patterns near the cranial floor; therefore, changes in pulse cycles and pulse repetition frequency were examined for reducing standing waves. Limitations and considerations for conducting ultradeep focal targeting in human applications are discussed.

Then there were 12: The illustrated cranial nerves from Vesalius to Soemmerring

In the second century ce, Galen described seven pairs of cerebral nerves. He did not name the nerves, nor did he illustrate his work. Galen's descriptive texts survived until the mid-sixteenth century, when anatomists, influenced by the artistic and scientific revolution of the Renaissance, began a reformation in anatomical research. They closely observed their own dissected material and conveyed their results not only in words but commonly by lavish drawings. Many of the great anatomists reexamined the cerebral nerves, adding descriptive text or changing the classification. In 1778, Thomas Soemmerring (1755-1830) named 12 pairs of cerebral nerves upon which the modern cranial nerve nomenclature is based. Soemmerring matched his text with clear, decisive illustrations. This article describes the works of some of the great artists in the period from Vesalius to Soemmerring and how they used illustration to supplement and provide clarity for their textual descriptions of the cranial nerves.

[Ophthalmic manifestations in COVID-19-associated multiple mononeuropathy of the cranial nerves (clinical observation)]

Clinical manifestations of the new coronavirus infection can vary greatly and affect different organs and systems. Despite the lack of convincing data on the possible direct damage to the structures of the eyeball by the SARS-CoV-2 virus, indirect involvement of the organ of vision both in the acute period of the disease, during the period of convalescence, and as a part of the post-COVID syndrome is common in clinical practice. The condition of the ocular surface is not given much attention during the treatment of the main disease, especially in severe cases, which can lead to serious complications and visual acuity loss after recovery. Timely measures can prevent the loss of visual acuity. This article presents a description and discusses a rare case of multiple neuropathy of the cranial nerves associated with COVID-19, with bilateral involvement of the olfactory (I), trigeminal (V), facial (VII) and sublingual (XII) nerves, as well as the right optic nerve (II), which required staged rehabilitation.

On old Olympus? Oliver Wendell Holmes and the origin and evolution of a mnemonic couplet for the cranial nerves

A mnemonic couplet to help students learn the names of the cranial nerves has been in use in the United States since the mid-nineteenthth century. The original in iambic tetrameter is attributed to Oliver Wendell Holmes, Sr. Using a systematic search, more than 40 variants have been identified and, where possible, ordered in time. Variations depended in part on evolving preferred names for individual cranial nerves, regional geographic features, and idiosyncratic choices. Some inferior variants ignored critical features of the original (e.g., meter, number of poetic feet, or even the rhyme). Others strove to have a memorable couplet with the basic features of the original but without resorting to disparaging phrases. However, with the modern names for the cranial nerves, few of the extant versions of the mnemonic make sense, or preserve iambic tetrameter and rhyme, while avoiding derogatory or lewd expressions. Two new versions are suggested that meet these constraints.

A guide to cranial nerve testing for musculoskeletal clinicians

BACKGROUND

Neurological examination in musculoskeletal practice is a key element of safe and appropriate orthopedic clinical practice. With physiotherapists currently positioning themselves as advanced first line practitioners, it is essential that those who treat patients who present with neck/head/orofacial pain and associated symptoms, should have an index of suspicion of cranial nerve (CN) dysfunction. They should be able to examine and determine if CN dysfunction is present, and make appropriate clinical decisions based upon those findings.

METHODS

This paper summarizes the functions, potential impairments of the nerves, associated conditions, and basic skills involved in cranial nerve examination.

RESULTS

A summary of cranial nerve examination is provided, which is based on the function of the nerves, This is intended to facilitate clinicians to feel more confident at understanding neural function/impairment, as well as performing and interpreting the examination.

CONCLUSION

This paper illustrates that CN testing can be performed quickly, efficiently and without the need for complicated or potentially unavailable equipment. An understanding of the CN's function and potential reasons for impairment is likely to increase the frequency of CN testing in orthopedic clinical practice and referral if positive findings are encountered.

Primary Extranodal NK/T-Cell Lymphoma Presenting as Neurolymphomatosis Involving Multiple Cranial Nerves: A Case Report

Neurolymphomatosis (NL) is a rare condition caused by the lymphomatous or leukemic infiltration of nerves and manifests as neuropathy. Most often, NL is associated with B-lineage non-Hodgkin lymphoma (NHL) and only infrequently occurs in conjunction with T- or NK-lineage NHL. Extranodal NK/T-cell lymphoma (ENKTL)-associated NL is exceedingly unusual, with only 9 cases described in the English language literature, in addition to our case. Diagnosis of NL is challenging, as the entity can mimic neuropathies of more common etiologies, and an adequate biopsy may be difficult to obtain. Timely diagnosis demands a high index of suspicion, especially for patients without a history of hematologic malignancy. We expand upon a unique case of NL exclusively involving cranial nerves and cauda equina nerve roots, as the initial manifestation of ENKTL, and contextualize our findings within the framework of previously reported NK/T-lineage NL cases.

Sonographic Multifocal Cranial Nerve Enlargement in Multifocal Acquired Demyelinating Sensory and Motor Neuropathy

Multifocal enlargements with the alteration of a normal fascicular pattern are considered to be sonographic peripheral nerve features in multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), a subtype of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We herein present the case of an 18-year-old patient with MADSAM in whom intensive sonological assessments revealed multifocal nerve enlargement within clinically affected cranial nerves. Our case demonstrated that, if systematically investigated with ultrasound, morphological changes similar to those in the peripheral nerves may be detected in a large proportion of clinically affected cranial nerves in MADSAM, boosting the future applications of cranial nerve ultrasound in CIDP.

[Patient treated for severe Covid-19 with paralysis of cranial nerves]

Patients with Covid-19 can experience neurological complications, for example cranial nerve palsy. We present a case with a patient treated for severe Covid-19 infection. She was intubated for 16 days and was ventilated in the prone-position for several hours a day during her care in the intensive care unit (ICU). She developed paralysis of the left facial nerve, observed while intubated. After extubation the patient was hoarse and had dysphagia and examination showed paralysis of the left hypoglossal nerve with the tongue deviating to the left and of the left vagus nerve causing a paralysis of the left vocal cord. It is impossible to know whether the paralysis of the three cranial nerves was due to direct damage by the Covid-19 virus or due to compression of the nerves during the ICU care. As facial nerve palsy has been shown to be more common in patients with Covid-19, we believe that the paralysis in our patient was due to a combination of both.

CRANIAL NERVE HYPERFUNCTION SYNDROMES. MODERN APPROACHES TO DIAGNOSIS AND TREATMENT (REVIEW)

In this article, we reviewed neurovascular conflicts of most cranial nerves with characteristic clinical syndromes and analyzed preferred treatment strategies, including surgical methods. We conducted literature review using the Pubmed database, selecting articles on cranial nerves compression syndromes, published for 10 years (from 2010 to 2020). The analysis covered all articles with information on the etiology, pathogenesis, clinical findings, diagnosis, differential diagnosis, neuroimaging, and pathomorphological assessment, as well as treatment strategies for such pathology, including surgical methods. After identifying all the articles that met the inclusion criteria and deleting duplicate data, 58 literature sources on cranial nerves compression syndromes associated with neurovascular conflict were selected. Cranial nerves compression syndromes are a complex interdisciplinary problem, often poorly understood and undetectable by neurologists. Literature sources describe cases of neurovascular conflicts with all cranial nerves except for the olfactory one. A blood vessel (an artery, less often a vein), typically in the area where a nerve root exits the brain stem acts as a compressing agent. Clinical findings are diverse and associated with nerve hyperfunction. The most common manifestations are trigeminal neuralgia, glossopharyngeal neuralgia, and hemifacial spasm. Currently, implementation of standard cranial nerve neuroimaging protocol using high-field high-power MR scanners, MR angiography, and DVI tractography into the diagnosis allows to timely detect neurovascular conflict and determine treatment tactics. Neurosurgical intervention should be considered in case of failure or poor tolerance of conservative treatment. In most cases, the operation of choice is microvascular decompression, the essence of which is to separate the compressing vessel from the nerve and insert a sponge between the nerve and the vessel.